Author Topic: Thinking about me P-38 as I'm bored at work...  (Read 2633 times)

Offline bolillo_loco

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Thinking about me P-38 as I'm bored at work...
« Reply #75 on: January 01, 2002, 11:32:00 AM »
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 ]

Offline HoHun

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Thinking about me P-38 as I'm bored at work...
« Reply #76 on: January 01, 2002, 11:58:00 AM »
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)

Offline F4UDOA

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Thinking about me P-38 as I'm bored at work...
« Reply #77 on: January 01, 2002, 01:22:00 PM »
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.

Offline gripen

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Thinking about me P-38 as I'm bored at work...
« Reply #78 on: January 01, 2002, 04:17:00 PM »
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 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

Offline Widewing

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Thinking about me P-38 as I'm bored at work...
« Reply #79 on: January 01, 2002, 04:37:00 PM »
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
My regards,

Widewing

YGBSM. Retired Member of Aces High Trainer Corps, Past President of the DFC, retired from flying as Tredlite.

Offline bolillo_loco

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Thinking about me P-38 as I'm bored at work...
« Reply #80 on: January 01, 2002, 07:21:00 PM »
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 ]

Offline Seeker

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Thinking about me P-38 as I'm bored at work...
« Reply #81 on: January 01, 2002, 08:42:00 PM »
Quote
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.

Offline batdog

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Thinking about me P-38 as I'm bored at work...
« Reply #82 on: January 02, 2002, 06:08:00 AM »
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
Of course, I only see what he posts here and what he does in the MA.  I know virtually nothing about the man.  I think its important for people to realize that we don't really know squat about each other.... definately not enough to use words like "hate".

AKDejaVu

Offline HoHun

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Thinking about me P-38 as I'm bored at work...
« Reply #83 on: January 02, 2002, 12:06:00 PM »
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)

Offline akak

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Thinking about me P-38 as I'm bored at work...
« Reply #84 on: January 02, 2002, 05:22:00 PM »
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.


 
Quote
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


--------------------------------------------------------------------------------

Offline batdog

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Thinking about me P-38 as I'm bored at work...
« Reply #85 on: January 03, 2002, 07:40:00 AM »
Quote
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
Of course, I only see what he posts here and what he does in the MA.  I know virtually nothing about the man.  I think its important for people to realize that we don't really know squat about each other.... definately not enough to use words like "hate".

AKDejaVu

Offline gripen

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Thinking about me P-38 as I'm bored at work...
« Reply #86 on: January 03, 2002, 07:56:00 AM »
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

Offline batdog

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Thinking about me P-38 as I'm bored at work...
« Reply #87 on: January 03, 2002, 09:26:00 AM »
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 ]
Of course, I only see what he posts here and what he does in the MA.  I know virtually nothing about the man.  I think its important for people to realize that we don't really know squat about each other.... definately not enough to use words like "hate".

AKDejaVu

Offline bolillo_loco

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Thinking about me P-38 as I'm bored at work...
« Reply #88 on: January 03, 2002, 11:17:00 AM »
sorry for partakiing in the hijacking of your original thread batdog.

Offline HoHun

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Thinking about me P-38 as I'm bored at work...
« Reply #89 on: January 03, 2002, 01:15:00 PM »
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)