Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: batdog on December 27, 2001, 09:31:00 AM
-
How do you gents feel about it? Is it complex,easy,modeled well now? Do you fly it much? How do you fly it..E,angles, both? Just some general talk here.
I personaly have been flying it alot this tour. I love it. I doubt many remember that when I first came here to AH I tried my beloved P-38 but well... it was beyond me it seemed and the fragilty of it made matters worse.
It seem now that after flying AH for abit (8 or 9 months?) I'm finaly able to fly my favorite WW2 plane decently. The fix for the damage model has helped considerbly.
I like to fly a mix of E and angles with it. It seems to be able to turn w/planes that are faster well for the most part. Some of this is fuel load of course. It zooms well and in a shallow climb goes like a bat outta hell. The guns seem good as well. I'm actually doing decently in my K/D ratio in it as well... considering I quess I enjoy T&B-ing in it alot...lol
Like I said just bored at work and feel like "chewing the cud" w/other gents out there about my favorite ride.
xBAT
--------------------------------------------------------------------------------
-
It only needs to have the dive flaps fixed. And a J & F model :D
I fly it as a turnfighter vs planes I cant outrun and as an E/Angles fighter vs those I cant out-turn.
-
Yea..same TAC. A GREEN P-38J would be nice...
xBAT
-
Hmm, I've encountered with tac's P-38 few times and I could swear I heard jet engines ;)
vector
-
Hey, it IS green aint it?. Since they havent put me green ride in, I have to look for the pleasure somewhere else.
And in this one you can hear the shrieking screams of the cons over the whine of the Jumo engines.
"sheeeeee *jet whine* eeeeeeeet" *pow*" :D :D :D
-
p38 rules
-
P-38 is an awesome plane, but you have to be an awesome pilot.
Its not like the Jug, that no matter how good a pilot you are, it will still be a toejam plane.
the P-38 is great in the hands of a good pilot, better than a pony, typhoon, hellcat, or corsair, imo.
-
Well I have replys from 3 of the most well known 38 sticks in AH and certainly some of the best if not the best. I've several members of my squad who have flown it this tour and a couple who fly it alot regardless. They do VERY well in it. I think you can safely say the SA is a big deal in a 38..more so than several other planes. This is prob why I had such a rough time in it earlier and still do now and then. By SA I dont just mean knowing whats around you but also understanding how YOUR plane stacks up vrs others. I mean if you decide to turn w/a brown colored spitfire dont be surprised when you go boom.
More comments,ideas?
xBAT
-
i do horrible in the p38...but i try real hard :) the only conflicts i run into with it are the nose guns. i cant hit watermelon unless its a flat shot. snapshots are almost impossible for me in this plane
-
I think the nose guns are abit wierd feeling at first. But after you fly it abit you seem to pick up on it. Snap shots seem abit harder in it but then again my gunnery skills arent all that. They seem to pack a good punch though if and when you get a good hit in, even w/out the one hispano.
xBAT
P.S. Your 38 flying seems fine to me. You've 20 more kills than deaths in it. I think most have a hard time breaking even in it.
[ 12-28-2001: Message edited by: batdog ]
-
I find the 38 now annoyingly durable (being a P51 driver mainly). I don't find I have much problem turnfighting them (except for the excessive ammo consumption) until they drag me to their friends though (which is what happens when you spend 10 minutes pumping ammo into them), or flail the stick so that I plow into them.
On the lighter side, I do enjoy the odd jaunt in a 38. However, it dosen't seem to enjoy me flying it.
-
Manxer, the P-51 was the least durable of any allied fighter.
(http://www.warbirdsresourcegroup.org/URG/images/p38-37.jpg)
Only a jug or a bomber would be able to take something like this and come home. A p51 hit like this would be a splat over the Ruhr.
In my opinion, the 38 now is modeled just about right on its damage. You can hit a 109 or a p47 or a spitfire with the 38's NOSE guns in the fuselage and it will still take a good hose to bring them down. Same with a pony. And its the same with the 38. The reason why the 38 seems so durable is because it doesnt have flimsy wing to snap off easily as other fighters have...because the 38 IS a wing with 2 tails.
-
Well the improved durablity had made all the difference in the P-38 to me. Its on par w/history I think now. I bet several die hard 38 sticks (TAC,Fester,etc)who have endured the 38 thoughout its AH path will testify about how frustratingly easy it was to kill in earlier versions. The most novice stick could just get a couple of pings in often and see the 38 lose its tail and fall back-ass-wards to earth. Even those whom seemed to dislike the allied plane set would comment on this at times. HiTech,Pyro and crew corrected this in the last version :)
xBAT
-
Hm... there was a USAF comparison on vulnerability of their fighters based on statistics and interviews of the pilots. Results were something like that the P-47 was the best and the P-38 and P-51 were about equall. Japanese rated the P-38 as most vulnerable and the F4U as most difficult to shoot down.
gripen
-
Hehe... the Japanese rated the 38 as the most vunerable? For some reason that seems wierd considering how well the 38 seemed to do vrs their plane set. Then again you have to look at what its competing against as well I quess.
The 38 in AH isnt as tough as the f4u or the 47. It does lose more parts than it use to though... ie when its hit it doesnt lose the rear end section 80 percent of the time.
xBAT
[ 12-28-2001: Message edited by: batdog ]
-
Some people complain about visibility and SA in the P-38L, I find it great. But maybe because I'm used to it.
The cockpit layout is very nice, and all around views are good, though you have to move the plane a little for better views in some angles.
As for the nose guns, I find them awesome. But then again I consider myself a great shot, in part because of my accurate HOTAS and rudder control. You get close to me in and you are going down. Its that simple, its a sniper. Its harder to hit with a concentrated burst, but when you get the hang of it, its better than the spread guns of other yankee planes. Specially if you get used to aim at specific plane parts, like the wings, tails, or my favorite; the cockpit. For shooting down bombers, aim for the wingtips.
[ 12-28-2001: Message edited by: Animal ]
-
Im still trying to get a handle on the 38. I fly it most of the time and usually get shot down. I still think its the best plane jsut trying to get a feel for how to fly it.
I have tried TnB fighting with it but I am either pciking the wrong plane to try this against or just stink at it (probably some of both). I have just started experimenting ith E fighting (BnZ) so dont have good opinion of this with the 38 yet. I have noticed that in a shallow climb it outclimbs anything and that the shallow climb combined with a BnZ attack makes the 38 pretty tough to catch by equal E or even slightly higher E fighters.
Anyone who can give me some other pointers or wouldnt mind spending some time helping someone get a better grip on this plane feel free to send me an e-mail or note.
Everyhting I have read about the 38 sasys it was the toughest lane of all the great WWII fighters to learn how to fly. Once mastered though it was one of the best if not the best fighter of WWII.
-
Heck after they toughened it up I still tried to kill other 38's with a spray of 50 cal expecting to see it break apart.
pre-fix you would hit with a spray and watch it lose a wing and see its tails flop away from it.
now it doesnt. You have to HIT it with a good burst to smack it down. Just like ANY other plane.
Im not sure about that durability thing of the 51 and 38 being equal.
Compare loss rate of 51 vs 38. The 38 lost a lot less planes than the p51, and the 38 saw action longer than the 51 and earlier, facing the best pilots the LW and the IJA/N had. Not bad for a plane twice as complex to fly for a recruit and with so many operational problems.
Also look at its K/D ratio. In the toughest times, vs the toughest enemy pilots, the 38 dished out much more grief than it received.
[ 12-28-2001: Message edited by: Tac ]
-
TAC, the P51 was not the least durable fighter. Its radiator was vulnerable, but thats it. I have a picture of a P51 with the pilot standing in a hole in the wing made from flak. Also, the P51s engine was capable of running without the radiator when raw fuel was pumped into the engine via the primer pump. Some pilots knew about this and were able to safely return to base after suffering radiator damage.
-
Least durable allied fighter. The zero I think was the least durable of them all :)
-
Does any one here bother trying to operate the two engines independantly at all?
When?
Why?
How?
And does it make a difference?
Any one know if pilots were trained to operate the engines independantly?
I'm suspicious that engine management (or lack there of) is one reason why sims never seem (in the eyes of 38 lovers) to do the 38 justice. Comments?
-
TAC,
Funny you should mention the K/D of the P-38 and the P-51. I have never seen detailed K/D numbers for each plane. Can you post that data if you have it?
For some reason the Navy/Marine birds and the RAF have far more detailed information available via the web as far as source documents. AAF birds which get far more notority IE. P-51, P-47 and P-38 are all but impossible to get your hands on those types of docs. Conspiracy?? :o
-
I used to have my dual throttle help me in doing tight turns Seeker, but since I upgraded to win2k I lost that ability in my stick :( *sniff*.
Single engine management helps a lot if you losing a wingtip, you can compensate and keep control of the craft.
F4udoa, I believe widewing posted that info earlier this year. It should be on this forum.
"Conspiracy??"
Dunno, Skully would disagree ;) :)
-
Tac,
I wonder on what statistics your claims are based? Generally P-38s and P-51s (RAF Mustangs) started operations about same time at spring 1942 and actually the Mustang saw serious combat earlier. And in the 8th AF the P-38 joined in combat just two months before the P-51B and from March 1944 the P-51 was more numerous than the P-38 (actually earlier if we count 354th FG). BTW the P-51 reached much better claim/loss (note word "claim") ratio right from the beginning in the 8th AF. About losses it should be also noted that if there is much more P-51s in combat (like in the ETO and later also in the MTO from June 1944 and against Japan from January 1945) then there is certainly more losses, there were not so much combat losses in Alaska or Latin America...
gripen
-
Originally posted by fdiron:
TAC, the P51 was not the least durable fighter. Its radiator was vulnerable, but thats it. I have a picture of a P51 with the pilot standing in a hole in the wing made from flak. Also, the P51s engine was capable of running without the radiator when raw fuel was pumped into the engine via the primer pump. Some pilots knew about this and were able to safely return to base after suffering radiator damage.
Ah, I don't think you'd get very far without coolant regardless of how much you operated the primer. Moreover, it seems like a good way to foul the spark plugs. If you had a minor leak, then I suppose anything you could do to reduce cylinder head temperature is beneficial, to a point. However, a solid hit to the radiator core or a partial severing of a Prestone line will result in powered flight that can be estimated in minutes. Very few minutes.
One disadvantage of having the radiator mounted behind the cockpit is the long lines required to circulate the coolant to and from the engine. This increases the likelihood of damage should the aircraft be hit. Inasmuch as most damage tended to be found aft of the cockpit, this also raises the odds of damage to the coolant system.
The same problem troubled the P-38, but it had that insurance engine, with which to get home.
My regards,
Widewing
-
Originally posted by gripen:
Tac,
I wonder on what statistics your claims are based? Generally P-38s and P-51s (RAF Mustangs) started operations about same time at spring 1942 and actually the Mustang saw serious combat earlier. And in the 8th AF the P-38 joined in combat just two months before the P-51B and from March 1944 the P-51 was more numerous than the P-38 (actually earlier if we count 354th FG). BTW the P-51 reached much better claim/loss (note word "claim") ratio right from the beginning in the 8th AF. About losses it should be also noted that if there is much more P-51s in combat (like in the ETO and later also in the MTO from June 1944 and against Japan from January 1945) then there is certainly more losses, there were not so much combat losses in Alaska or Latin America...
gripen
I agree. P-38 losses operating with the 8th AF were consistantly higher per sortie than for the P-51, with several exceptions that can be discounted due to non-combat related events. Indeed, there are a myriad of reasons for this, but the fact is indisputable that air combat losses were less per sortie for the Mustang. Most of those reasons have been expounded on here in the past. I will limit my comments to this: Once the P-38L began to arrive in the ETO, the kill Vs loss ratio just about equalized between the two types. In North Africa and the MTO, the P-38 performed much better than in the ETO. We need not discuss the SWPA as this was a vastly different type of airwar than that found in Europe.
I'm afraid that TAC is mixing his apples and oranges.
My regards,
Widewing
-
Then indeed I was. Thanks for the info widewing :)
<F> all you pony drivers ;) :D
-
Hi everyone,
since we already had apples and oranges, I'd like to add some pears now ;-)
According to K. H. Regnat's "North American P-51 Mustang", the A-36 Apache squadrons in Europe flew 23400 sorties, dropping 7248 t of bombs, scoring 84 air-to-air kills and another 14 air-to-ground aircraft kills, but losing 177 aircraft themselves.
That's equal to a 682 lbs of bombs per sortie, and a loss rate of just 0.76%. I'd tend to think that in an overall WW2 context, this was a rather low loss rate, but it would be highly interesting to see comparable figures for other fighter bombers!
Regards,
Henning (HoHun)
-
HoHun,
362nd FG (P-47s) of the Ninth Air Force, from June to October 1944, flew 6,488 sorties and lost 59 aircraft (0.91% loss rate) and 54 pilots. Their losses were apparently slightly higher than average.
(Over the same period, the 362nd was credited with 49 kills, 2 probables and 11 enemy aircraft damaged.)
-
Hi guys, nice thread!
When I log on, I decide I want to fly a P-38. Looking at the map, how do I decide where to go? I've been flying the P-51 for a while now, so I look for a big gob of enemy and get some alt then slash through them. This doesn't work with the P-38(for me anyway).
Also, I don't think anyone mentioned Dive-bombing. Air to mud is not really my thing, but I try to stay competent. Any tips?
-
Originally posted by Tac:
Then indeed I was. Thanks for the info widewing :)
<F> all you pony drivers ;) :D
It is sometimes hard to understand exactly why the P-38 suffered hard times in the ETO if all that is examined is the operational record.
There was nothing fundamentally wrong with the P-38 as flown by the 8th AF. Pilots who had previous combat experience in the type had the utmost confidence in the big fighter. There were mechanical issues relating to a lack of cockpit heat, excessive cooling of the intake air in the intercoolers (P-38J). Leaking and inefficient intercoolers (P-38H). Frozen turbocharger regulators and a complex engine management system were other little ditties that made life difficult for 8th AF P-38 jocks. Add to this the bad judgement that plagued 8th leadership. P-38 groups were given none of the formalized training that was later supplied to the P-51 groups entering the theater. In an insane hurry to resume deep penetrations into Germany, the 55th and 20th Fighter Groups were committed recklessly to high altitude, long range missions for which they had never trained for or had time to debug their aircraft and correct the inevitable gremlins that were sure to turn up. So, they suffered disproportionally during the first two months of operations. Then things got worse. As the P-38H fighters were replaced by the new J models, engines started blowing up with great regularity. Replacement pilots were assigned from the general pool, with very few ever having flown a P-38 or attended a stateside RTU for the type. Mission schedules demanded max efforts and pilots were being worn down to a frazzle. Maintenance crews worked around the clock just trying to keep the battle-weary fighters operational, and had virtually no time to tackle the mechanical problems that were threatening to ground half of the available aircraft. Eaker turned a deaf ear to the requests for technical assistance citing the P-38's good performance in the MTO. Finally, the USAAF had enough of Eaker and replaced him with Doolittle, who then proceeded to do much. He ordered an investigation into the problems being experienced by the P-38 Groups. When he finally had answers, he implemented changes, which included special fuel for the Lightnings to minimize detonation. He took the recommendations of his combat pilots and went to Lockheed with them. Gradually, the P-38J was being made combat fit. However, Doolittle couldn't wait for the new P-38L. The P-51 was proving to be the solution to the long range escort problem, and he determined to switch over the entire 8th Fighter Command to the Mustang.
When the new L model arrived, it had simplified engine controls, working heat, dive flaps and hydaulically boosted ailerons. Indeed, the big fighter was all it should have been six months earlier. Yes, it was still burdened with a low critical Mach.
Yes, it still required nearly twice the fuel and maintenance manhours. However, it was now capable of being flown by less experienced pilots and gradually regained some of its early war stature. Sent to fly with the 9th AF, the Lightning provided great service, usually flying down low where it really shined.
As I see the P-38, it was a design ahead of its time, but so badly managed that it did not reach its peak until after its time had passed.
Of course, in the Pacific, things were greatly different. Different mission, different environment, different enemy. Even when the P-51D became available to General Kenney's 5th AF, he preferred the P-38. Why?
Simple reasoning. Unlike Europe, where if you suffer a failure or battle damage, you can bailout over dry ground, this was not
usually an option in the SWPA. Even if you were fortunate enough to parachute onto dry land, no one wanted to be taken prisoner by the Japanese. Kenney found that his pilots were far more comfortable with two engines. When they were more comfortable, they were also more aggressive. He liked the fact that the P-38 could lift more ordnance, and could suffer more battle damage than the Mustangs. With no measureable advantage in actual combat performance, Kenney was inclined to stick with the fighter that had done the job so well for so long. Eventually, Mustangs made inroads simply due to the limited number of replacement P-38s. However, it was never as popular with the SWPA pilots as the P-38. Although the ground crews found that one engine and related systems sure made their lives easier.
Remember, a well flown P-38 was a match for any enemy. Which, I suppose, is what everyone is finding out on AH.
My regards,
Widewing
[ 12-29-2001: Message edited by: Widewing ]
-
Well, there were couple things fundamentally wrong with the P-38; the concept was wrong and aerodynamics sucked. In practice there were also lot of technical problems which made situation even worse.
The twin engine concept with turbocharged engines was very expensive and also mainteance nightmare; actually advanced P-38 develoments were based on mechanically supercharged engines. The twin engine concept also caused poor acceleration in the roll specially at low speed; the P-38 was a high speed energy fighter as it was used in Pacific.
The aerodynamic problems were more serious; critical mach number was low specially under g load at high altitude. Also Clmax dropped fast when mach number increased. The P-38 was not particularly maneuverable at high altitude.
With redesigned wing, tail and fuselage the P-38 might have been a good but very expensive long range high altitude escort fighter, something like DH Hornet couple years later. But with original aerodynamics the P-38 was destined to low altitude operations; actually even 5th AF knew this, they choosed the P-51 for escort missions.
BTW all this have been discused several times here...
gripen
-
But with original aerodynamics the P-38 was destined to low altitude operations; actually even 5th AF knew this, they choosed the P-51 for escort missions.
Are we talking about the B-29 escort missions over Japan here? Those were flown by Seventh Air Force...
-
Originally posted by gripen:
Well, there were couple things fundamentally wrong with the P-38; the concept was wrong and aerodynamics sucked. In practice there were also lot of technical problems which made situation even worse.
I see, you disagree with Kelly Johnson about concept and aerodynamics. Even though Johnson was lead designer of the F-104, U-2 and SR-71, and by extension, should have at least a journeyman's understanding of the science, right?
Hmm, let's see, can you name any other twin engine interceptors (or twin fighters of any kind) that offered performance even remotely close to the XP-38, circa 1938-39?
Perhaps you don't understand the specification that the P-38 was required to meet. It required a rapid rate of climb, high speed and good endurance. None of these could be met with the normally aspirated engines in existance at the time (1936-37). So, it was determined to use the new Allison V-1710, but to have the power required at altitude, Johnson elected to incorporate the new GE turbosupercharger. Gee, he couldn't have been far off the mark as the aircraft exceeded every requirement.
As to the aerodynamics, I suppose you are commenting on the the airfoil section. Well, Johnson knew that this aircraft would need to carry considerable fuel. Where to put that fuel was the issue. He elected to put in the wing, and selected an airfoil design already in use on the Electra. Perhaps not the best choice, but one he believed to be adequate. Several years later Johnson admitted that they never believed that severe compressibility problems would ever be an issue when they did the initial design. Lockheed wasn't the only aircraft manufacturer to find this out the hard way.
As it was, Johnson and his team had originally looked at six different configurations, rejecting one after another for various reasons until only the twin boom design remained. Preferring a much thinner airfoil (chord/thickness ratio), Johnson tried to find the internal volume to pack in 400 gallons of avgas. After weeks of hard work, that produced no easy solution, Johnson was forced to make a decision as the drop-dead date approached. He scrapped the thin wing and (with management's blessing) selected the NACA 23016 section for the inner wing, and the NACA 4412 section for the outer wing. Essentially, this was the same as the Electra. It is also generally believed to be the first fighter to use metal covering on all control surfaces.
Meant to meet the requirements of specification X-608 (the content of which was leaked to Johnson 6 months before being officially released), Johnson was confident that it would win the competition hands down.
On April 13, 1937, Johnson submitted his aerodynamic study to the Air Corps. They reviewed his data, and forwarded it to NACA,
which endorsed the engineering.
So, if you find fault in the aerodynamics, you do so only with the hindsight advantage of 65 years of development in the science of aerodymanics since Johnson first penned the concept in the Fall of 1936.
The twin engine concept with turbocharged engines was very expensive and also mainteance nightmare; actually advanced P-38 develoments were based on mechanically supercharged engines. The twin engine concept also caused poor acceleration in the roll specially at low speed; the P-38 was a high speed energy fighter as it was used in Pacific.
You have overlooked the simple fact that this was the only viable solution with the then available powerplants (1936-37).
However, Johnson tried to take advantage of the new Rolls Royce Merlin engine (in 1941), but the Air Corps, and later, the War Production Board were having none of it.
The aerodynamic problems were more serious; critical mach number was low specially under g load at high altitude. Also Clmax dropped fast when mach number increased. The P-38 was not particularly maneuverable at high altitude.
I think that everyone is aware of the P-38's Mach limits. You also need to understand that the original design was intended to be a high-speed bomber interceptor, and maneuverability at high altitude was not an issue at that time.
With redesigned wing, tail and fuselage the P-38 might have been a good but very expensive long range high altitude escort fighter, something like DH Hornet couple years later. But with original aerodynamics the P-38 was destined to low altitude operations; actually even 5th AF knew this, they choosed the P-51 for escort missions..
As I've explained, a redesign was not going to happen. Recall that the WPB rejected Lockheeds request to close down the production line for two weeks while they make the required tooling changes to incorporate the lower RPM Hamilton-Standard propeller. What chance existed for a major redesign? None. By the way, the P-38 WAS a good high altitude escort fighter. It just wasn't the best. If it was so bad, why did the P-38 maintain a better than 2:1 kill/loss ratio, even during its most troubled 8th AF days in the ETO?
The Hornet benefitted from 7 more years of aviation development, most of it in the war years with the associated rapid advances in engines and aerodynamics. So, this is not a fair example. Although, you may wish to re-examine the layout of the P-82 Twin Mustang. Even with 7 years of technological advances, North American still elected a twin-engine, twin-boom design. Before you point out that they did not incorporate the central pilot gondola, have a look at the F-82s that actually served and take note of that massive radar pod, right there between the engines. Of course, there were other aircraft that used this basic layout as well, with the P-61 and XF-11 coming to mind.
As to the use of the P-51 in the 5th AF, you need to have a look at the force composition of the 5th. Mustangs did not arrive until 1945, and they did not replace the P-38, but rather the P-47Ds then in service. Towards the end of the war, the 5th AF and 13th AF merged to become the Far Eastern Air Force (FEAF). Kenney never gave up his Lightnings, for reasons already expounded upon. The Air Force that first re-equipped with the Mustang (in the Pacific) was the 7th, which went to war at Saipan with P-47Ds. Later, their new Mustangs would escort the B-29s to Japan, along with the P-47N. Kenney's Lightnings were busy working over Formosa and the coast of China from bases in the PI.
My regards,
Widewing
-
I am curious how to read the dive chart in the pilots manual, it seems to taper off at the top as the G's increase, and I do understand that the more G's pulled the airfoil suffers worse compressablility, however it seems the straight lines represent 2G's or more depending on the altitude and as the placarded speed is lowered more G's are pulled. for example the 420 placarded limit at 10,000ft goes up beyond the 4 g line, the 360 placarded limit at 20,000ft goes to about 3 gs and the 290 placarded limit at 30,000ft runs to about the 2g line. my question is why is this chart printed in this fasion and what does it imply? a quick link for reference
http://www.zenoswarbirdvideos.com/More_P-38_Stuff.html (http://www.zenoswarbirdvideos.com/More_P-38_Stuff.html)
thanks
[ 12-29-2001: Message edited by: bolillo_loco ]
-
Originally posted by bolillo_loco:
I am curious how to read the dive chart in the pilots manual, it seems to taper off at the top as the G's increase, and I do understand that the more G's pulled the airfoil suffers worse compressablility, however it seems the straight lines represent 2G's or more depending on the altitude and as the placarded speed is lowered more G's are pulled. for example the 420 placarded limit at 10,000ft goes up beyond the 4 g line, the 360 placarded limit at 20,000ft goes to about 3 gs and the 290 placarded limit at 30,000ft runs to about the 2g line. my question is why is this chart printed in this fasion and what does it imply? a quick link for reference
http://www.zenoswarbirdvideos.com/More_P-38_Stuff.html (http://www.zenoswarbirdvideos.com/More_P-38_Stuff.html)
thanks
[ 12-29-2001: Message edited by: bolillo_loco ]
Since I have several P-38 manuals handy, I'll try to answer your question. Instructions for the use of the Figure 25 dive chart are in the manual.
Basically, any combination of speed and G loading that moves above or to the right of the respective curve will induce buffeting. The reason the curves roll off to the right is that buffeting can be induced at zero G if the airspeed exceeds critical Mach. Remember, the chart indexes speed, load and altitude. This is why it provides three curves for 10k, 20k and 30k.
Does this help any?
My regards,
Widewing
-
Say what you will guys, but here are the facts.
The P38 was one of the best early-mid war planes there was. And it was outstanding in the Pac fighting what were in essence second rate Japanese aircraft.
But put it against any of the front line fighters of the late war and it losses.
Sorry, but thats the facts. Live with it.
-
Yeah Verm, and pilot accounts (both allied and axis) where sensationalist lies.
-
There's nothing wrong with the airfoils on the P-38. The naca 230xx is the same series used on the F6f, F4u, Fw-190, etc and the 4412 has probably the best Lift/Drag of any airfoil out there. The problem with the lower critical mach number comes from having more surface area covered by propwash. If there is any thrust being made, air is accelerated. If the airflow is being restricted through the prop disc, then it tends to flow *around* the high resistence areas into other flow areas and when you put more air into a volume, it's pressure and velocity increase (put your thumb over the end of a hose spraying water), so there's no way around it with a multi-engined design except to put the engines behind the rest of the airframe. But, the benefits of that design, with it's counter-rotating props would seem to outweigh the negatives. No torque, multi-engine reliability, tricycle landing gear, more efficient thrust are all on the plus side. With the way the props rotated, the upflow on the inner wing section caused it to stall first, allowing a higher taper ratio, moving the mean chord closer to the center line, reducing bending loads on the spar and structural weight requirements. Even the higher aspect ratio stabilizer reduces trim drag. The fowler flaps are brilliant. So it had a large wingspan and slower rate of roll, that's about the ONLY negative thing aerodynamically speaking.
I think I'd rather fly a P-38 1000 miles from home than a 51, for sure. Of course, the P-47 is the first choice! :D
-
not really widewing, let me explain it a bit farther
with the dive chart that states 420 mph ias at 10,000ft, the way I read the chart/graph it means about 4-5G's may be pulled before buffeting begins, at 360mph ias at 20,000ft it looks like just a little under 4G's may be pulled and at 290 mph ias at 30,000ft just over 2 g's may be pulled before buffeting will be encountered, this is with out dive flaps extended of course.
at least that is what the chart looks to say to me, but please feel free to correct me.
-
The P38 was one of the best early-mid war planes there was. And it was outstanding in the Pac fighting what were in essence second rate Japanese aircraft.
But put it against any of the front line fighters of the late war and it losses.
I don't know about that, Vermillion. Sure, an early-mid war P-38F or G is no match for a late-war fighter. The early-war P-38s were quite different from the late-war P-38s, though.
I've cited "Corky" Smith before (12-victory ace with the 80th FS, "Headhunters") on the relative merits of the P-38--here's a more complete quote:
"The P-38 was the finest fighter aircraft in the theater--P-51s came in when the war moved into the Philippines. I flew the P-51 after the war over a two year period. A good ship--but could only better the P-38 at altitudes over 20,000 feet. It was well suited for the European theater where high altitude combat was predominant--In the Pacific the bombers flew at tree-top level. Plus, the twin prop of the 38 would bring us home on one when we got shot up. If we had been flying the P-51, many of us would not have made it back. I came home five times with one engine shot out. Lucky, I guess."
In general, the accounts I've read seem to favour the P-38 at medium and low altitudes, the P-51 at high altitudes and the P-47 at very high altitudes.
-
Originally posted by bolillo_loco:
not really widewing, let me explain it a bit farther
with the dive chart that states 420 mph ias at 10,000ft, the way I read the chart/graph it means about 4-5G's may be pulled before buffeting begins, at 360mph ias at 20,000ft it looks like just a little under 4G's may be pulled and at 290 mph ias at 30,000ft just over 2 g's may be pulled before buffeting will be encountered, this is with out dive flaps extended of course.
at least that is what the chart looks to say to me, but please feel free to correct me.
Yep, that's how I read it too. However, I can only wonder about the value of this chart, inasmuch as to my understanding, the P-38 didn't have a G meter. So how could you use the chart without some reference other than the seat of your pants?
My regards,
Widewing
-
Mach number relates to the true airspeed. As altitude gets higher, the TAS will be lower for any given mach number. What that chart says:
420 ias @ 10k = 489 tas = M 0.666
360 ias @ 20k = 493 tas = M 0.697
290 ias @ 30k = 473 tas = M 0.697
As for the g limits, that's the flight envelope of the plane. You can't pull more G's without stalling, but the angle of attack is the same.
The 1G stall speed works out to 205-210 mph ias according to those values (at all heights), so it shows that the maximum lift coefficient is greatly reduced at Mach 0.7.
-
Widewing
re: the ability of the P51 to fly on the primer when radiator damaged.
"Ah, I don't think you'd get very far without coolant regardless of how much you operated the primer. Moreover, it seems like a good way to foul the spark plugs. If you had a minor leak, then I suppose anything you could do to reduce cylinder head temperature is beneficial, to a point. However, a solid hit to the radiator core or a partial severing of a Prestone line will result in powered flight that can be estimated in minutes. Very few minutes."
If you have or can get a copy of "Death Squadron" by Grover C. Hall jr, start read of this subject at page 363 where apparently
John Godfrey returned from near Berlin to England using this primer tactic.
Dont mean to dispute your seemingly vast knowledge of the subject.
:)null
-
Guppy,
I don't know about the P-38 being considered superior than the P-51 below 20K. In the Joint Fighter Conferance in 1944 a poll of fighter pilots from the Navy, Marines, AAF, RAF and contractors including Lockeed the question was asked which Fighter A/C was the best below 25K the P-38L received 0% of the vote. By contrast the P-51D received 29% of the vote, second to the XF8F. These were not Ensigns and First Leutenants making the evaluation. These were Combat pilots and experianced test pilots.
As a side note the Marines Nickname for the P-38 was "High altitude Foxholes".
-
Then If I have read the chart right, with out dive flaps you may be at 10,000ft going 420 mph ias and pull out at up to 4 to 5 G's before the A/C will experience buffeting.
Isn't this similar to the dive speed restrictions placed on the Corsair? The corsair would not have had as much problems due to the fact that it operated mostly at altitudes of 20,000ft and below and also it did not pick up speed as quickly as the 38 did in a dive.
I remember the dive and dive recovery section in america's hundred thousand went into great detail for the corsair. it gave 1 G dive limits, 3 G's, and more.
if the placarded limit of 420 mph ias and 4-5 g's pull out with out dive flaps, what is the 1G limit for this plane at 10,000 ft with out dive recovery flaps? It would be higher than 420 mph ias.
thank you.
-
if the placarded limit of 420 mph ias and 4-5 g's pull out with out dive flaps, what is the 1G limit for this plane at 10,000 ft with out dive recovery flaps? It would be higher than 420 mph ias.
Yes, it probably would be, but you won't be recovering from that dive. A 4G pullout at 500 mph TAS will take over 4000 ft to recover and a 2G pullout = 8000 ft, so there appears to be a margin of error built in to the limits to account for terrain height and whatnot. One could probably dive up to 500 ias at say 2500 ft and be able to pull out at the 7G airframe limit within one wingspan of the water, but I doubt anyone ever tested that! :)
-
Originally posted by Bonden:
Widewing
re: the ability of the P51 to fly on the primer when radiator damaged.
"Ah, I don't think you'd get very far without coolant regardless of how much you operated the primer. Moreover, it seems like a good way to foul the spark plugs. If you had a minor leak, then I suppose anything you could do to reduce cylinder head temperature is beneficial, to a point. However, a solid hit to the radiator core or a partial severing of a Prestone line will result in powered flight that can be estimated in minutes. Very few minutes."
If you have or can get a copy of "Death Squadron" by Grover C. Hall jr, start read of this subject at page 363 where apparently
John Godfrey returned from near Berlin to England using this primer tactic.
Dont mean to dispute your seemingly vast knowledge of the subject.
:)null
I have referred the source to several friends who own and fly Mustangs, or who have extensive time in the type. However, I suspect that Mr. Hall has made an error, or he has been misinterpreted. I'll post what I learn here.
My regards,
Widewing
-
Well, there was not much wrong (except price) with the concept of the P-38 if it had been used just as a high-speed bomber interceptor. But during war the AF wanted a long range and high altitude air superiority fighter and for this the concept of the P-51 was far better. And V-1710s with turbos were not particularly good choice; problems still continued at 1944.
I wonder where I have disagreed about aerodynamics with Kelly Johnson? He and his team knew problems and possible solutions very well and they certainly knew that there was no quick and easy fix. And it was not just the profiles but also the fuselage and wing center section between booms which caused a big part of the problems as proved with the modified P-38 with revised fuselage and wing center section and wind tunnel tests.
And no, the P-38 was not a good high altitude fighter. It could not be used as energy fighter at high altitude due to compressebility problems. In horizontal plane it was not particularly maneuverable at high altitude due to limitations of the airframe (Clmax dropped fast when mach number increased) and poor roll acceleration. In all these areas the P-51 was much better at high altitude. BTW the P-51 was THE escort fighter of the USAF, against Germany and also against Japan.
About flight envelopes and Clmax values it should be noted that I posted some useful links some time ago, too lazy to link them here again...
gripen
-
F4UDOA,
Yeah, the P-38L didn't do well at the Pax. River conference. I've only skimmed the report, but I got the impression many pilots were unimpressed with the Lightning's quirks (terrible cockpit layout, greater inertia than single-engined types, and so on).
As regards the "high-altitude foxhole" reference, I'll post an excerpt of an interview with a then-Marine major on Guadalcanal.
"The 38s' first deployment forward to Guadalcanal was before I arrived, I think, in late 1942. That initial deployment was not a success. I don't mean to cast any aspersions at all, but I think that some of the pilots who brought the P-38s up there the first time didn't have the confidence in the aircraft that the later pilots did. When I arrived, some of them would be drifting back to Guadalcanal a half an hour before the strike part of a mission returned or had even been heard from. I'm sure that the air corps pilots of that day heard about it, but other pilots, marine, navy, etc., referred to the P-38 as a 'high altitude foxhole.'
...
"In any case, I attributed the initial situation to a hurried transition and the lack of time for confidence-building... later, it was a total turn-around--about the best airplanes and the best pilots we had."
-
thank you wells, so with the dive flaps the 420 mph ias for a 4-5G pull out may be exceeded by 20 mph ias according to the pilots manual, this means 440 mph ias and a 4-5G pull out at 10,000ft, isn't this similar to the performance of the F4U-1D according to america's hundred thousand?
In the PTO during most of the war didn't most fighters operate from short unimproved airfields? wouldn't that make the P-38 better suited than the mustang to take off from short strips with heavy loads? also they seemed to make better use of the range of the P-38 in the PTO than the ETO so that with the use of better cruise control methods and 310 gallon drop tanks the 38 actually had more endurance than the P-51D. was or wasn't range and lifting ablity more critical in the PTO?
even in the MTO when bombing the oil fields in rumania, 38s carried one 1,000lb bomb to the target, could the P-51D fly all that distance and carry a 1,000lb bomb load over that distance and still return?
grippen, I do enjoy reading the links you post and other information. I hope to soon purchase some more books and the ones you pointed out to me
Tim Mason: The Secret Years
David Birch: Rolls Royce and the Mustang
Ken Delve: The Mustang Story
Jeffrey Ethell: Mustang - a Documentary History
can somebody explain what all these numbers mean?
http://naca.larc.nasa.gov/reports/1947/naca-rm-a7f09/index.cgi?page0022.gif (http://naca.larc.nasa.gov/reports/1947/naca-rm-a7f09/index.cgi?page0022.gif)
thanks. :)
-
Here's the F4u graph:
(http://www.iaw.com/~general6/f4u_limits.jpg)
-
Originally posted by Widewing:
I have referred the source to several friends who own and fly Mustangs, or who have extensive time in the type. However, I suspect that Mr. Hall has made an error, or he has been misinterpreted. I'll post what I learn here.
My regards,
Widewing
Ok, I have had several responses, and I found the original story as related by Jim Goodson, who flew with Godfrey.
The damage received to Godfrey's Mustang was from flak. Apparently a coolant line was nicked by a shell splinter and developed a relatively minor leak. Typically, a fighter like the Mustang would get into trouble once the cooling system pressure began to fall. If it falls too far, the Glycol will boil in the cylinder head, raising the temperature rapidly. Add to that a slight leak, and you have the makings of big trouble.
Goodson relates that he had used his primer pump to keep cylinder head temps down after taking a hit in his oil cooler. He barely made it back to Britain from the easten edge of France. However, he was flying a P-47D-10 at the time, which has an air-cooled R-2800 radial engine. This motor can survive at high temps much longer than a Merlin. My experience with radials is based upon over 2,000 hours of flying in aircraft powered by the R-2800 and R-1820 as Flight Engineer and Crew Chief.
Godfrey was advised to try the primer to keep the cylinder temps within limits. He did so and managed to get to the North Sea.
However, his hand was in severe pain and the coolant level had dropped to a point where pumping raw fuel into the cylinders was no longer of any value. As the engine began to knock and seize up, he prepared to bail out and stood up in the cockpit, Just then, he spotted the coast of England ahead. His engine quit shortly thereafter and he dead-sticked into a meadow just in from the coast.
In this case, Godfrey suffered a minor leak. Had he lost most of his coolant, he would have watched the engine seize within minutes.
Now, here's what Dudley Henriques has to say. Dudley has about 5,000 hours in Mustangs, having owned a few.
"I've heard this story several times. I wouldn't recommend it!!!
:-))
Excessive overheat in the 51 can mean big time trouble. 121c degrees is the magic number. Anything over 110c is suspect. With a maximum overheat you get a pop off valve release and plenty of white smoke past your ears. With the rad switch on auto, the flap opening is controlled by coolant temp. You can over ride and hold it open for a short time if it's set on auto and see if that brings the temp down. If that fails, and it most likely will at that point, you have a big problem going!! On the right side of the seat you have an emergency coolant flap release you can yank, but once you do, this can't be reset in flight...it's a one shot deal. This extends the coolant flap opening.The problem with the flap release is that if the actuator hasn't failed, you now have to use higher power settings to compensate for the open door. It's a bit tricky.
Bottom line on overheat in the 51 is that if it's an actuator failure or anything else morting the coolant system, I'd go through the procedure above and get the damn thing on the ground in one hell of a hurry! :-) I don't know about Godfrey, but if it was me, I'd give a lot of thought to using that damn sensitive primer on an already excessively hot and running Merlin.
:-))))"
Gene Greisell adds:
" A Merlin suffering a total coolant loss had, as you said, very few minutes to live. Between 30 seconds to 2 minutes before it seized, IIRC. A slow leak - as you suggested - might - allow, with a combination of low power gliding and rich mixture (and flapping ones arms out the cockpit maybe), to achieve a considerable range, but somehow I don't think 400 nmiles could be made unless the leak is so insignificant as to be barely noticeable."
You can read Goodson's account of these two events in his book, Tumult in The Clouds.
My regards,
Widewing
[ 12-30-2001: Message edited by: Widewing ]
-
Hey thanks a bunch wells!
-
Thanks Wells, BTW Clmax data from the report of the joint fighter conference results suprisingly similar envelopes.
gripen
-
is it possible that the P38 was even worse in diving than the charts would you make think? I mean they talk about speed limits in IAS but when i look at the flight operation chart from zenoswarbirdvideos:
(http://www.zenoswarbirdvideos.com/Images/P-38/38FOIC.gif)
you can see that the error between IAS and TAS is high. Even near ground (bottom left corner) for continous power it IAS is 12mph higher than TAS (314 / 302). The trend is that with more speed the error becomes larger.
And at high altitude the error is extrem: in 30k IAS = 252MPH, this is afaik 414mph TAS according to standard conversion tables (factor 1,644) - BUT the chart says TAS = 388MPH. This is an error of 26mph. And for full power (wep) the error would raise maybe to 35-40mph. And at 500mph and high mach numbers....
Of course the dive tables speak about IAS because itīs useful for the pilot - this is what he can read from the instrument. But with this large error the mach limit looks imo higher than it has been in reality. AND itīs imo the reason why you can read a lot of excellent speed claims from P38 pilots. They knew about standard conversion factors, but i think few of them did know about the error of the speed indicator, escepially with increasing mach number
niklas
[ 12-31-2001: Message edited by: niklas ]
-
Been watching this thread I can see its gone full circle from AH to a lesson in history, which is a good thing really.
I am NO expert but from what I've read the 38 was an awesome ride that was basicly pushed right into combat w/out much if anything know about many of the "problems" it was to face..ie critical Mach numbers, high alt performance etc. When WW2 hit the P-38 was handsdown the most advanced concept of a fighter we had I think.
The war dept wanted planes so the 38 was thrust into service. It was the first plane to do those high alt long range escorts w/mostly novice pilots to it.
The P-38 required a good amount of familiarization I think as well being a high performance TWIN engined fighter. Those poor pilots that where thrust into it from the first part of the war simply had to fiqure it out on thier own in combat. The 8th airforce had no training in place for these pilots. I wonder how many more would of perhaps lived if they'd had some foresight.
The 38 was very succesful in the Med and PAC theater. WHY was it better there? Well the alt of the fights had alot to do with it as the Euro theater brought about the unknown at the time problems of high alt, long range escorting w/basicly unproven engines at that alt.
I hear people say the 38 faced inferior planes in the PAC. The first years of the 38's fight in the PAC the Japanese where anything BUT inferior. They had many of the best pilots in the world and the Zero was still a formiable plane. In the Med theater they faced german 109's and Fw's. The held thier own at a miniuim.
Basicly the P-38 was a plane that under trying circumstances held its own. Due to the time of the war and how it was going against us it wasnt afforded several things that could of made it much better, much earlier... ie engines (perhaps Merlins), Paddle Props (ie the lost K version), etc.
xBAT
P.S. (edited) Looks like Widewing already said alot of this...lol.
[ 12-31-2001: Message edited by: batdog ]
-
bolillo_loco,
Well, symbols are described in page two of the that NACA document. Shortly those graphs gives windtunnel data about relations between angle of attack and lift coefficient (left side of the graphs) and relations between lift coefficient and pitching moment coefficient (right side of the graphs) at several mach numbers and various configurations.
About dive flaps and flight envelope it should be noted that at high mach numbers those flaps extended the envelope. In the case of the P-47 dive flaps increased maneuverability above about mach 0.6 and below this speed dive flaps actually restricted maneuverability if controll forces were not the limiting factor. I don't know exact value for the P-38 but based on data on those couple NACA documents, similar mach number appears to be around mach 0.5-0.6.
About loadings of the planes it should noted that a bigger and more powerfull plane can certainly carry a given weight (say a 1000lbs bomb or what ever) much easier than a smaller and less powerfull plane. The P-38 was certainly better than the P-51 in this area.
Generally all WWII era airspeed indicators were quite unaccurate but there was somekind of primitive mach meter in the late P-38 models.
IMHO the P-38 was a good plane for pretty much everykind of tasks at below say 20k if the pilots knew the limitations of the plane and used right tactics (but even in the Pacific and Mediterranean pilots learned this hardway in the beginning). But above that altitude... well, think yourself.
gripen
-
Widewing:
"Goodson relates that he had used his primer pump to keep cylinder head temps down after taking a hit in his oil cooler. He barely made it back to Britain from the easten edge of France. However, he was flying a P-47D-10 at the time, which has an air-cooled R-2800 radial engine".
Book says they were in Mustangs. Just relayin what I've read. Perhaps the author did get it wrong or misinterpreted but, I would be disappointed to have to add grains of salt to every WW2 account I have read!
Anyway, appreciated your reply. It's a good read. ("Death Squadron") none the less. :)
regards
-
bollilo_loco,
You do realize that that the F4U chart is in Knots not MPH?
At 10,000Ft the restriction is roughly 425Knots or 490MPH IAS. That is not the same as the P-38 even with dive flaps.
Also the airspeed correction chart for the P-38 indicates an error in airspeed increasing as speed increases.
At 356MPH IAS the CAS is 340MPH
AT 377MPH IAS the CAS is 360MPH
So you can see an error in airspeed increasing with speed showing a minimum error of -20MPH at 420IAS really being 400MPH CAS.
The F4U also has an error in this regard
At 280Knts IAS the CAS is 287Knts
At 300Knts IAS the CAS is 308Knts
Showing an increase in CAS by +1 KNt for ever 10Knts. So 420KNTS IAS in the F4U is really closer to 430KNTS TAS or 500MPH.
Thanks
-
Originally posted by Bonden:
Widewing:
"Goodson relates that he had used his primer pump to keep cylinder head temps down after taking a hit in his oil cooler. He barely made it back to Britain from the easten edge of France. However, he was flying a P-47D-10 at the time, which has an air-cooled R-2800 radial engine".
Book says they were in Mustangs. Just relayin what I've read. Perhaps the author did get it wrong or misinterpreted but, I would be disappointed to have to add grains of salt to every WW2 account I have read!
Anyway, appreciated your reply. It's a good read. ("Death Squadron") none the less. :)
regards
Goodson originally used the primer pump to cool the engine while flying his beat-up P-47D. Godfrey used the primer pump to cool his leaking Mustang on the suggestion of another pilot who knew of Goodson's experience several months earlier.
Godfrey was flying a P-51B. So, the book is correct on that.
My regards,
Widewing
-
yes I realize that the corsair chart is in knots, could somebody please post the corsair dive restriction speeds in mph ias/tas for 1G 3Gs and 5Gs at 10,000ft from america's hundred thousand?
since the 38 is restricted to 440 IAS with dive recovery flaps at 10,000ft for what looks like a 5G pull out and not 1 G, it looks like it was not that far behind the corsair at all.
I have read where others have stated that the 47 and 51 pilot could dive from high altitude and compress, then just wait to hit dense air and the plane would recover. I do not believe this statement because when reading the pilots manual, they gave quite a few pull out charts for 350mph ias and 450 mph ias and different angles of attack that one would need to begin pull out. It also stated that once the plane encountered compressablility one had to recognize the warning signs early and reduce power and wait to recover. There are quite a few graphs and warnings about compressability in the P-51 manual. This would lead me to believe that none of the ww2 a/c including the 51 were safe in high speed dives from hi ias and hi altitude. they just didnt recover on their own from these altitudes on their own the pilot really had to know what to do not to make the dive worse.
what I am saying is that take a 47/51 to 30,000ft and make a power dive beginning from an airspeed of 400 mph tas, you should not recover. The fact that so many rumors surrounded the 38 most likely terrified pilots and they were very careful not to dive too fast may be one reason why less 38's were lost in dives vs 47's or 51's.
mechanical reliability, anybody who has Roger Freemans book on the mustang, turn to the back and read all the mechanical problems and restrictions that were placed on the 51 due to mechanical problems, it looks like the 51, 47, and 38 all had about the same about of problems in this area, ie a lot.
thanks
-
also on the speed chart if you look to the far right colum it says ias is 161 and the tas is 168. also in the chart if it says the ias at 252 is really 377 tas how do you know how tas was measured?
-
IAS is converted to CAS (instrument installation error)
CAS is converted to EAS (equivalent airspeed is corrected for compressibility)
Then, EAS is converted to TAS
In Aces High, IAS = CAS, or so I thought Pyro mention at one time.
-
bolillo_loco,
First it should be noted that you can easily do speed conversions with that chart yourself, so please...
The P-51 could be recovered from dive when desired even if it was at compressebility speeds. But increased g load at compressebility speeds caused increased buffeting which could damage plane so that's why manual recommended that plane should be dived to the lower altitudes where it came out of compressebility self. Anyway, a skilled pilot could recover the P-51 anytime if he wanted that and it was pretty much same with the F4U and P-47 (if elevator lockup did not exist, or with dive flaps on later models). BTW I believe I have told all this to you before...
About problems of the P-51 it should be noted that there are several books (I have seen Freeman's book too) which lists problems including mission aborts (again help yourself) and so on... there were problems but these were solvable or tolerable and it's same with the P-47. But in the case of the P-38 problems were never fully solved and if there were less P-38s than P-51s and P-47s then there were certainly less diving accidents too. Generally the P-51 and P-47 were far better high altitude fighters than the P-38.
BTW I wonder if you have a somekind of obsession about the P-38 because you continously try to bend all data to favor it...
gripen
-
IF the 51 recovers all by itself and so does tne P-47 then why do the pilots manuals for these respective a/c and or training films show graphs and flim clips of what happens when you start a power dive (full throttle all the way down) and do not reduce power the plane will fly into the ground? there is a film at zenos which shows the altitude needed to recover from a downward maneouver at high speeds. at very high speeds and high altitude the 47 will not recover from the split s, atleast that is what the film clip shows.
It seems that the L version solved early problems and or brought the probles of the earlier 38s up to the standards of other a/c of the day.
I pointed out how Freeman's book showed many of the problems that the 51 had and not all of these were fixed by wars end. airframe failures due to excessive gs either in combat maneuvers or pull outs plauged the 51 till the end of the war, atleast that is what Roger Freeman's book states. Seems the 51D gained too much weight for the airframe. this is understandable since it was not as big as either a 47 or a 38.
I am not bending information. I am only restating what I have read. when I made mention of martin caiden's and warren bodie's books it was said that both the authors were questionable. I guess roger freemans books are not any good either.
Is name calling next?
thanks.
-
Hi Bolillo_loco,
>I have read where others have stated that the 47 and 51 pilot could dive from high altitude and compress, then just wait to hit dense air and the plane would recover.
Don't mix the P-47 and the P-51 here: The P-47 did indeed have history of compressiblity-induced "graveyard dives" just like the P-38. The P-51 did not.
As quoted by you, the statement is not correct: The P-51 would not recover by itself, but after diving at constant true air speed to a lower altitude where the Mach number for this air speed was lower, it was fully controllable once again.
>I do not believe this statement because when reading the pilots manual, they gave quite a few pull out charts for 350mph ias and 450 mph ias and different angles of attack that one would need to begin pull out.
The P-51 manual makes it quite clear that the only danger in high-speed diving with the Mustang is failing to pull up in time to avoid hitting the ground.
The P-38 (and the P-47, too) are in a much more dangerous category: They will destroy themselves in mid-air if they get too fast. They'd develop a pitching-down moment much more powerful than the pilot's controls to counter it, forcing the aircraft into a negative-G (outside) loop that would quickly exceed the structural limits of the airframe.
Any P-38 attempting to go to the P-51's maximum possible Mach number would end up as a cloud of debris even before hitting the ground - dive brakes or not.
Regards,
Henning (HoHun)
-
bolillo_loco,
I wonder who has claimed that the P-51 or P-47 recovers all by itself? I quess you have missunderstood something now, actually a lot believe or you are trying to bend data to favor the P-38 again...
The L version did not fix aerodynamic problems mentioned before and it's reliability at high altitude was never really tested in service because it was used mostly as a fighter bomber.
All mentioned planes could damaged or even destroyded with too high g load including the P-38. With correct fuel management and trim use g loads were not a problem for the P-51. BTW I have pointed this out couple times before...
So far I have not said anything about Freeman's credibility (but you have). Also I have not questioned Bodie's credibility but questioned his claim about 1725hp rating as the standard. Caiden's credibility is an another story but I'm not alone in that case...
gripen
-
The P-38 is one of the few planes in the arena that has a sizeable advantage in at least one category against virtually every other aircraft.
No matter what it goes up against.. it can do at least one thing better.
AKDejaVu
-
well then I am sorry I misunderstood you grippen I have been known to do that and my misunderstanding of data and the way I pose questions is not always the best way I am sure.
but keep the stuff coming any way I enjoy reading what you all of you people have to say, hohun, wells, widewing, and f4udoa to mention a few. :) atleast I am not drunk anymore and ranting and raving.
what I am trying to understand is since the 38 dive chart is G rated it looks to be just a bit but not too far behind the corsair for similar g load pull outs. I do understand that if both planes were at 30,000 ft at the same speed the 38 would suffer more from compression due to the fact that the 38 will pick up speed much more quickly than the F4UD. I get the opinion that some believe that at 20,000 ft from low to medium ias that if you dove a 38 it would just compress and go into the ground or break up in mid air, but then again I could be wrong.
-
bolillo_loco,
Well, seems that your serie of missunderstandings still continue; those flight envelopes just gives us buffeting (or stall or tuck under or what ever) boundary. In practice this means that forexample the F4U started to buffet at high speeds when limits were reached but pull out was still possible. Also I don't know if the P-38 was much better than the F4U in the dive acceleration.
gripen
-
HoHun,
Does the P-51 manual say anything about the possibility of the Mustang shedding wings in a high-speed dive and pullout? I seem to recall a thread about that on these boards, some time ago.
-
Hi Bolillo_loco,
>I get the opinion that some believe that at 20,000 ft from low to medium ias that if you dove a 38 it would just compress and go into the ground or break up in mid air, but then again I could be wrong.
I'm beginning to share Gripen's impression that you're falling victim to selective perception when it comes to the P-38. Here's what I actually wrote:
"Any P-38 attempting to go to the P-51's maximum possible Mach number would end up as a cloud of debris even before hitting the ground - dive brakes or not."
The advantage of a P-38 in a dive is better initial acceleration (i. e. higher specific excess power at slow speed). The disadvantages are lower top speed, lower critical Mach number, and a negative pitching moment in a dive.
What happens if a P-38 goes into a diving contest with the P-51 from equal, low speed? First, it will have the advantage of higher specific excess energy and accelerate faster. Knowning that, the P-51 pilot will put his nose down sharpy. At high altitude and low speed, the thrust to weight ratio of a propeller fighter may be 1:5 (high estimate in favour of the P-38).
If you're going straight down - which the Mustang pilot will - the "thrust to weight ratio" of gravity is 1. The benefit of propeller thrust is comparatively small that way, and the benefit of the P-38's higher specific excess power is even smaller. What's more, diving straight down will result in rapid acceleration so that the P-38 will leave its region of superiority very quickly. Besides, with increasing speed, the thrust provided by the propeller will drop, making it pretty much insignificant in comparison to the "thrust" provided by gravity.
In short, the "better initial dive acceleration" observed in a low G pushover is a good estimate of specific excess power for this flight situation, but in an all-out combat dive, it means little.
Now we have two aircraft going steeply down at high speed. As soon as each of them reaches the level top speed for the altitude, it starts losing energy. The P-38 is slower, so its acceleration will begin to fall back behind that of the P-51. Soon, the P-38 will reach its critical Mach number, which means a dramatic drag rise, so it will fall back behind the P-51 even more. Extending the dive recovery flaps now will add yet more drag, and let the P-51 pull away even further. When the P-38 comes up against the maximum allowable Mach number with dive brakes extended, it can't hold the dive angle or it will enter a negative-G loop overstressing the structure. So the P-38 will have to break off chase of the P-51 that's far ahead by now anyway.
Even worse: The steeper the dive is, the more allowance the P-38 pilot has to make for the additional acceleration during the pull-out process. The above sequence is probably only possible for fairly shallow dives - in a vertical dive, the P-38 pilot would have to begin the pull-out very early to make sure he doesn't exceed the maximum Mach number with dive brakes extended in the pull-out. Due to the uncontrollable nose-down moment this would stop the pull-out and push the plane into the dive again - and into self-destruction.
The P-38 certainly was a very successful fighter in several theatres, but with regard to high-speed diving, it was simply crippled. Not due to bad design, I'm sure - in fact, the P-38 was a very advanced and sophisticated aircraft in many areas.
Widewing summed it up pretty well:
"So, if you find fault in the aerodynamics, you do so only with the hindsight advantage of 65 years of development in the science of aerodymanics since Johnson first penned the concept in the Fall of 1936. "
The British aerodynamicist Sir Morien Morgan stated the same in greater detail:
"Looking back, I think that the greatest problem at the end of the 1930s was that it was extremely difficult to visualize what combat would be like in the new monoplane fighters; the only air fighting experts we had were from the First World War and that had been twenty years earlier. I think we all paid too much attention to the behaviour of an aeroplane flying on a calm sunny day and harmonizing the controls so that they could do nice aerobatic displays; we seemed to miss the importance of handling at speeds around the maximum permissable, in fast dives. Before the war, I remember, people thought that it was rather an academic exercise to scream downhill at one's maximum permissable speeds."
Regards,
Henning (HoHun)
-
Hi Guppy,
>Does the P-51 manual say anything about the possibility of the Mustang shedding wings in a high-speed dive and pullout?
It warns several times against pulling out abruptly. Since the manual considers 4 G "about what the average pilot can withstand without blacking out", I'd say their main concern was G-induced loss of consciousness.
Regards,
Henning (HoHun)
-
Originally posted by Guppy:
HoHun,
Does the P-51 manual say anything about the possibility of the Mustang shedding wings in a high-speed dive and pullout? I seem to recall a thread about that on these boards, some time ago.
S!
I recall reading somewhere that even P-47 pilots been warned not to add too much manual trim to get out of the compressions, it'd broke the airframe.
-
I have never read in the pilots manual about sheading wings for a 51D in a dive. I do remember reading it in Roger Freemans book. I believe it was caused by the clips that held the ammo and gun access doors in place as well as the landing gear bay doors. it resulted in a few cases of complete wing loss in hi speed dives. so a temporary 450 mph dive speed limit was placed on the mustang.
I never intended to say that the 38 was able to dive to mach .8 and if anybody mis-read that I am sorry.
what I would like to know is could somebody explain why in a dive from 20,000ft to 10,000 ft where recovery was performed why america's hundred thousand says the P-38 would out accelerate the mustang and be the first one at that altitude.
this could be for the mustangs with the fabric covered elevators. the fabric would buldge and cause porpoising. this began at mach .75 the manual I read clearly stated that you had to reduce power or this condition would worsen and become vilotently dangerous if power was not reduced.
so basically grippen and hohun what you are telling me is that a mustang could enter a powerdive from 30,000 or maybe even 40,000ft at true airspeeds of 400 mph and dive full power straight down and recovery could be done when ever the pilot felt like it, providing of course there is enough altitude for the pull out. the pilot need not fear crashing into the ground nor reduce power because the mustang could be safely flown to (I believe one of you two stated mach .86 safely)
so if this is true the section on dive and dive recovery for the P-51 in americas hundred thousand is wrong when it stated that after dives at mach .79, .80, .81, and .83 the tests were stopped because they felt it was no longer safe to proceed any further and that the mustang had recived considerable airframe damage and the a/c had to be written off?
these are questions, thanks.
[ 01-01-2002: Message edited by: bolillo_loco ]
-
Hi Bolillo_loco,
>I never intended to say that the 38 was able to dive to mach .8 and if anybody mis-read that I am sorry.
What I said was quite clear:
"Any P-38 attempting to go to the P-51's maximum possible Mach number would end up as a cloud of debris even before hitting the ground - dive brakes or not."
You answered:
"I get the opinion that some believe that at 20,000 ft from low to medium ias that if you dove a 38 it would just compress and go into the ground or break up in mid air, but then again I could be wrong. "
If someone misread something here, it was you.
Unfortunately, I have to point out that it was not the first time I felt inadequately paraphrased by you.
>so basically grippen and hohun what you are telling me is that [...]
No, it's not.
Have you thought about using direct quotes? Quite a common technique in online fora, and it helps to prevent misunderstandings.
Regards,
Henning (HoHun)
-
Here is an excerpt from a test at Elgin Field on a Mock Combat of a P-38J and a P-51B. It pretty much says all that has been questioned and answered already.
The turning circle of the p-51B is smaller than that of the p-38J-5, at all altitudes. It has a far faster rate of aileron roll through all speeds. The p-51B accelerates rapidly away from the p-38J in a dive, after reaching speeds of 325 I.A.S. With both planes in formation at cruising speed in level flight, when full power is applied, the p-38J will pull several hundred feet out in front before the p-51B can reach maximum acceleration and overtake the p-38J. With slight advantage in altitude, the p-51B can jump the p-38J successfully and engage in combat, due to its superior diving and top speed. The p-51B can evade being jumped by the p-38J, if it is seen in time, by dropping the nose and diving away. If the p-38J has built up its speed in a dive and is not seen in time, the p-51B can turn sharply into the p-38J and evade its fire. The p-38J cannot follow the p-51B at high diving speed at altitude, due to its lower limits of allowable diving speeds. At high speed, it is impossible for the p-38J to keep its sights on the p-51B due to the p-51B's rapid rate of aileron roll, allowing it to reverse its direction of turn faster than the p-38J can follow.
I hope this can help.
-
Thanks F4UDOA, it's the same report I quoted some time ago, actually all USAF comparisons I have seen state pretty clearly that the P-51 had better dive acceleration than the P-38. Maybe at low altitude and if dive angle is very low the P-38 might have a initial advantage but so far I have not seen real world test which support this.
bolillo_loco,
The dive capability comparison in the AHT appears to be based on the calculations just like level flight accelerations (exhaust thrust and propeller efficiency are not counted nor drag at given Cl/speed/weight combination).
The fabric covered elevator was not a big problem if the plane was trimmed nose heavy and correct control techniques were used (see The Mustang Story p. 116 and AHT p.345), Borsodi did his dive tests with fabric covered elevators. BTW I have told this before...
No one has claimed that full throttle vertical dive with 400mph TAS starting speed from 30-40k all way down would have been safe with the P-51. Borsodi made 32 dives and reached mach 0.86. In that mach 0.86 dive radiator damaged but the plane was under control all the time. What I have stated is that the P-51 could start dive from high altitude at high speed and enter compressebility speeds (above mach 0.75) and recover safely if correct control techniques were used (please consult those references).
The Wright field test claimed in the AHT is a good example about phenomena I described above ie it was not recommended to pull out from dive if the plane was allready in the compressebility speeds because buffeting would increase when g load increases and might damage plane. And again it should be noted that during this test many dives were made and the plane stayed under control all the time.
And it was certainly possible to broke wings of the P-51 during the pull out if correct control techniques (nose down trim) and fuel management (not too much fuel in the fuselage tank) were not used. But it was same with pretty much all other planes too.
HoHun,
I believe that Kelly Johnson and his team did best they can with the aerodynamics of the P-38. There just was not enough knowledge when the P-38 was designed and it appears that there was a bit plain bad luck. This (http://naca.larc.nasa.gov/reports/1947/naca-rm-a7c24/index.cgi?page0023.gif) graph explains pretty well what went wrong. The wing itself without fuselage does pretty well at Cl 0.1; up to about mach 0.75 there is no tuck under and at Cl 0.2 tuck under starts at about mach 0.72. But everything changes with standard fuselage ie tuck under starts around mach 0.67 depending on Cl. With revised fuselage tuck under starts at low Cl values around mach 0,7 and this was confirmed with a modified plane which did safely more than Mach 0.7. So with a different fuselage the P-38 might have been much safer in dive but there would have been still problems under higher g loads.
The Clmax qualities of the wing is another story but I don't know how much of the drop is caused by the fuselage and wing center section. Probably Johnson and his team were aware about Clmax drop but they were designing a interceptor after all, not a dog fighter.
gripen
-
Another follow-up on coolant loss in a Mustang.
Vlado Lenoch wrote back with the following:
"I believe this story wasn't completely accurate or totally complete. I believe
that Godfrey experienced a partial coolant loss if any at all. Using the
primer is rather a common remedy for a carb. failure.
However, I once had a complete loss of main coolant in the Merlin. This
happened unbeknownst to me, on the ground and at idle power never exceeding
1200 rpm. The engine essentially froze in 7 minutes. We only had to change
the heads for a repair. We couldn't turn the prop by hand after shutdown. We
had a massive leak in a lower coolant line fitting. I can't imagine this
happening to Godfrey in the air and making it back home to England. (When I
close my eyes on this one, molten metal comes to view!!).
On another problem/failure, I had a loose coolant temperature probe, which is
located on top of the engine. I flew for a several hours until I found the
problem. I lost a couple of quarts of coolant and saw no cockpit indication of
any problem. I was very irritated at not being able to find the leak right
away. The airshow crowds loved my antics searching for the leak, because I
took off the cowling each time giving everyone time to study the powerplant! I
have painted my engine blocks yellow since then, so leaks can be spotted
faster. (I know, I know....it really looks good, once you get used to it!!
Trust me!! The bees love it in the summer!!)"
Vlado owns a P-51D, "Moonbeam McSwine", which makes the national airshow tour every year. He also owns and flys a Lockheed T-33.
All responses were posted to the rec.aviation.military newsgroup where I posed the question.
My regards,
Widewing
-
thanks guys for the explanations and the time it took to type partial data from reports.
hohun, my computer skills are even more limited than my knowledge of ww 2 a/c. I really do not know how to reply with quotes, but I will make it a point to learn. thanks for showing me my errors.
[ 01-01-2002: Message edited by: bolillo_loco ]
-
Originally posted by bolillo_loco:
I really do not know how to reply with quotes,
It's the right hand button with the two quote marks as an icon running along the top of every post.
-
How in the heck did my post about the 38 w/in AH suddenly turn into a pissing contest between the P-51 and P-38?
Go drink some left over egg-nog and let it die.
xBAT
-
Hi Batdog,
>Go drink some left over egg-nog and let it die.
If you don't want to read it, don't read it.
Regards,
Henning (HoHun)
-
I can't say how the P-38 flew before I started AH 3 campaigns ago but I can say it is modeled more realistically than the P-38 in Air Warrior and is a much better ride in AH. As some of you ex-AWer's know, AW had pretty much castrated the P38 for playability issues.
Don't know about anyone else but I didn't find the P-38 to complex to fly in AH, maybe it was because I've flown the thing for the past 8 years exclusively in AW. The only problem I had in transitioning over was the couple of weeks it took to get used to the new flight model. SA is a lot easier in the P38 in AH than it was in AW, that's due to being able to modify the views.
I took a lot of flak in AW for only flying one plane but I've had a life long fascination with the P-38 and at least for me, no other plane comes close to providing me the enjoyment I get from flying the Lightning.
As for fighting styles, I've found out that a mix of E and TnB fighting has worked best for me. Like TAC mentioned earlier, I usually use E tactics on planes that turn better than I do and a blend of E and TnB tactics on faster planes like the 190 and Runstang. With those planes, I use E tactics (even if I have lower E) to get them to burn their E state enough that they are either forced to run or turn fight. One thing that has helped me a lot is that I've been able to use the same tactics I used in AW in AH, with the exception of dragging Dweebfires to the deck and out turning them in a turn fight. Found out my first day in AH, dragging Dweebfires to the deck to turn fight them was a quick way to get back to HQ.
My only problem now is my gunnery. It's improved a hell of a lot since I started AH but I'm still missing some very easy shots that I should be able to make without any troubles. I'm sure with time that will get better but it's frustrating saddling up on a Laffer 200yrds on front of you and all your shots either go long or wide.
Originally posted by batdog:
How do you gents feel about it? Is it complex,easy,modeled well now? Do you fly it much? How do you fly it..E,angles, both? Just some general talk here.
I personaly have been flying it alot this tour. I love it. I doubt many remember that when I first came here to AH I tried my beloved P-38 but well... it was beyond me it seemed and the fragilty of it made matters worse.
It seem now that after flying AH for abit (8 or 9 months?) I'm finaly able to fly my favorite WW2 plane decently. The fix for the damage model has helped considerbly.
I like to fly a mix of E and angles with it. It seems to be able to turn w/planes that are faster well for the most part. Some of this is fuel load of course. It zooms well and in a shallow climb goes like a bat outta hell. The guns seem good as well. I'm actually doing decently in my K/D ratio in it as well... considering I quess I enjoy T&B-ing in it alot...lol
Like I said just bored at work and feel like "chewing the cud" w/other gents out there about my favorite ride.
xBAT
--------------------------------------------------------------------------------
-
Originally posted by HoHun:
Hi Batdog,
>Go drink some left over egg-nog and let it die.
If you don't want to read it, don't read it.
Regards,
Henning (HoHun)
Well... considering it was a thread I DID start I feel I have some "right" to make a comment. Maybe you should start a new thread w/your topic and go from there.
xBAT
-
Well, IMHO part of the discussion has been about flying qualities of the real P-38 at high altitude. I believe everybody wants realistic simulation, so what's wrong with it?
gripen
-
Baaaa... on 3rd and 4th thoughts...what does it REALLY matter. Go ahead and discuss away. As long as it stays civil.
I have a Chicken Pot Pie I need to eat. :)
xBAT
[ 01-03-2002: Message edited by: batdog ]
-
sorry for partakiing in the hijacking of your original thread batdog.
-
Hi Batdog,
>Well... considering it was a thread I DID start I feel I have some "right" to make a comment. Maybe you should start a new thread w/your topic and go from there.
We're right on the topic you defined in the subject line. If there's something specific you'd like to learn about the P-38, maybe you should start a new thread with a specific subject and go from there.
Regards,
Henning (HoHun)
-
Well.. no. The fact is I started this thread to discuss the P-38 w/in AH as is. It degressed to a technical discussion that has little to do w/impressions of the plane w/in AH. If you fly it w/in AH I wished to chew the fat so to speak.
BUT upon further reflection IF you had bothered to read my post below that you will see I realized that it didnt matter and any info at this point is good information.
xBAT
-
Hi Batdog,
>BUT upon further reflection IF you had bothered to read my post below that you will see I realized that it didnt matter and any info at this point is good information.
Glad to see you're happy again :-)
Thread creep is unavoidable I'm afraid, but you could try to turn that into an advantage by posting something that encourages it to creep into the desired direction :-)
For example, after the detailed discussion of the real P-38's dive characteristics, do you think Aces High has modelled it correctly?
How does the AH P-38's dive compare to that of the other planes mentioned in this thread in your opinion?
Regards,
Henning (HoHun)