What happened to LW?

[Widewing]

Originally posted by Karnak

There is something I would like to point out about the dive acceleration that people keep talking about.  You seem to think that it was much different than it was.  I recall that somebody, Widewing I think, posted text from the USA's comparitive flight trials of the A6M2 against various USN ans USAAF fighters.  The American fighters pulled away from the A6M2 in a dive as you'd expect, however the actual distances gained on it were not nearly so large as you would expect.  I don't remember the numbers so I won't post guesses, but I do remember it totally changed my take of things like the RAF's description of the Fw190's diving capability compared to the Spitfire Mk IX's.

That was from the TAIC test of the F6F-5 and A6M5. Initial dive acceleration was about equal. However, thereafter the F6F rapidly pulled away.

During this testing a maximum speed of 335 mph was recorded for the Zero and 409 mph for the F6F-5. Virtually every captured Zero tested displayed a max speed below that claimed by Mitsubishi. I recall something close to 318 mph for the A6M2. TAIC used independent air speed measuring equipment (independent of the aircraft's pitot system).

My regards,

Widewing

[milian]

Terminal Velocity does NOT rely totally on mass.

lol, terminal velocity has everything to do with mass!

normally, in level flight, drag = thrust, at terminal velocity, drag = weight.  Typically, at terminal velocity, the prop produces no thrust but an excess amount of drag.

(Remember the 2 cannonball test from the tower in Pisa as well as the feather and hammer on the moon, - remember Newton)

double LOL.  That is NOT mass, that is DENSITY!

But the feather and hammer is a good point, but not on the moon where there is no air resistance.  The heavier object WILL fall faster if the air resistance is in a non-negligable ratio to weight.  Sure, if you drop a 1 lb bowling ball and a 10 lb bowling ball where air resistance is .00001 ounce, sure, you will not notice a difference.  But if air resistance was at 1 lb, perhaps like tying the same size parachute to each, the heavier object WILL fall faster.

Such is terminal velocity, at very high speeds just think of the drag created by the airframe as a small parachute.  

Not sure if there is a crossing point, but if it is, it is not at top speed.

usually at best climb speed, for the spit 1, it is 140 mph, the 109 is 155 mph.  You will not that the climb speed in the spit is given as 170 mph, this IS NOT the best climb speed, 140 mph was found to be too slow for controlability and for cooling in the radiator.  

if we can find out the root cause of the Fw's low-speed handling/spin and acceleration woes

it's in the stall speed, plain and simple.  Test it yourself.  Take a 190 and decelerate while keeping the climb rate close to 0, and find out the speed where you can no longer keep a 0 climb rate.  Then try it with a P-51, they should have just about the same stall speed.  Then try it with a Spit, there shouldn't be more than a 10-15 mph difference.  Fixing the stall speed in the 190 will fix most all it's problems.  

As for the acceleration, you have to go way back here:

http://homepage.eircom.net/~frontacs/WBStored/Engines.html

The 190 could produce up to 300lbs of exhaust thrust to give you an idea of how significant it could be to top speed.

One big benefit of the mechanically driven supercharger is that the exhaust can be used to augment thrust. Trust me, this is a much bigger deal than it sounds. It doesn't give much of a performance boost to low end acceleration or climb, but it does have a big effect on top speed.

hmm, let's see, 300lbs of exhaust thrust at top end, but "doesn't give a performance boost to low end acceleration" . . .

geez, umm, let me guess, exhaust thrust is added at the top end of the 190 which means it nerfs the low end performance . . . and since there is no exhaust thrust figures given on the Spit or the Pony, it's not included. jeebus crispus, talking about "cheary" picking the data.

[Crumpp]

but I do remember it totally changed my take of things like the RAF's description of the Fw190's diving capability compared to the Spitfire Mk IX's.

I have those trials too, Karnak.  The point is not how little the difference was when measured side by side.

If you read the rest of the report, the point is those small difference add up to HUGE advantage in actual combat.  

At no point could the Zeke follow any of the US fighters in the verticle during mock combats.

During this testing a maximum speed of 335 mph was recorded for the Zero and 409 mph for the F6F-5. Virtually every captured Zero tested displayed a max speed below that claimed by Mitsubishi. I recall something close to 318 mph for the A6M2. TAIC used independent air speed measuring equipment (independent of the aircraft's pitot system).

What do you expect Widewing??  How many Mitsubishi mechanics or Zeke crewchiefs did the TAIC employ?  None....

Why people expect a foriegn power during wartime to be able to know the intricacies of an enemy design is beyond me.  It simply does not pass the common sense test.

Additionally the conditions of the South Pacific are some of the harshest in the world on mechanical equipment.  The humid salty air can corrode metal in a very short time.  It was not uncommon for all combatants to lose power on their aircraft after a short period of time in the field under those conditions.  You cannot expect any aircraft to be maintained in top condition for very long in primative conditions in harsh enviroments.  

It is easy to spot the maintenance mistakes made in the allied FW 190 test's by being familiar with maintenance requirements of the aircraft.

All the best,

Crumpp

[Crumpp]

The greater the drag the lower the acceleration and hence the lower the climb rate.

That is not true according to the results of flight-testing.  The greater the drag, the steeper the angle of climb and slower the best climb speed.

Both the P 51 and the FW 190 have less drag than the Spitfire. Yet the Spitfire out climbs them.

Both the P51 and the FW-190 climb at a faster best climb speed and shallower angle than the Spitfire.

Interesting phenomena with the FW-190 too.  The FW-190G8 has much higher drag than the FW-190A8 and is heavier.  The FW-190G8's climb rate is substantially greater.  It climbs at a slower speed but much steeper angle.  The FW-190G8 is also slower than the FW-190A8.  It has more drag.

In the climbing test of the FW-190A8 with Zustatzkraftstoffbehälter, the climb rate at low altitudes with the drop tank actually increases dramatically as well.  The angle steepens and best climb speed slows way down.

All the best,

Crumpp

[Krusty]

Well in AH that isn't modeled. I've tested many aircraft to see if changing the speed will help boost climb rates. In AH you have a +/- 10 mph margin (using autoclimb) where you'll be about the same ROC as default climb speed. If you reduce it (say in a spit from 170 to 130, say in a 109 from 155 to 110) you will only get a short boost as the nose rises, but once the plane quickly settles into steady climb your ROC is much worse than it was at default climb rate.

In AH, that is.

[Widewing]

Originally posted by Crumpp

What do you expect Widewing??  How many Mitsubishi mechanics or Zeke crewchiefs did the TAIC employ?  None....

Why people expect a foriegn power during wartime to be able to know the intricacies of an enemy design is beyond me.  It simply does not pass the common sense test.

Additionally the conditions of the South Pacific are some of the harshest in the world on mechanical equipment.  The humid salty air can corrode metal in a very short time.  It was not uncommon for all combatants to lose power on their aircraft after a short period of time in the field under those conditions.  You cannot expect any aircraft to be maintained in top condition for very long in primative conditions in harsh enviroments.  

I have no idea why you must argue with everyone about everything....

I am merely reporting what the tests revealed, moreover Saburo Sakai told an interviewer that the maximum speed of the A6M2 was just 315 mph.

You should also note that skilled engine mechanics can tune virtually any engine, especially when TAIC had captured manuals for the Zero and its Sakae radial. Let's go further and understand that TAIC was staffed by some of the Navy's best aero engineers. I'd wager that the Japanese personnel responsible for maintaining that Zero never had it running better than TAIC did, and likely not even as well.

As to the effects of deploying aircraft at sea, there's nothing you can tell me about that. Why? Because I was the senior Petty Officer responsible for maintaining several Grumman recip aircraft (C-1A) deployed aboard the USS Saratoga during Med deployments. Basic maintenance will keep powerplants running at full power. We never saw a loss of power in any of our R-1820s. They ran like Swiss watches.

My regards,

Widewing

[Squire]

You think maybe the navies of the world had some experience dealing with the sea air on aircraft?

All the combatants in the Pacific understood full well what was required to keep a/c and engines running properly.

Just as they understood what was required to maintain engines in the freezing cold and dust of the Eastern Front, or the dust of the Med and other regions.

All combat a/c suffered from hard use, no matter where they were deployed <.

Furthermore, you seem to think that allied mechanics were just plain stupid. That they couldnt change out plugs, or perform maintenance on an engine (theirs or anybody elses), just because they weren't certified by BMW or Mitsubishi, "wow its a radial engine never SEEN one before Billy".

TAIC can't do it huh? what did they do, drive to some gas station along a state highway and recruit from there? "Come on pard, hyuk yuk, well throw in a case of lucky strikes for ya too...hell ya, bring the pig, yeehaw!"

[Crumpp]

I have no idea why you must argue with everyone about everything....

Not arguing with everyone, just you Widewing.  Just you when you make erroneous assumptions or silly statements such as the massive contribution to the war effort the P47M made.

Facts are you are extremely biased and your post is another "axis data cannot be trusted" implication.

You should also note that skilled engine mechanics can tune virtually any engine,

Sure that is why Toyota racing hires Ford factory mechanics.

Tell that to the RAE.  They got ONE BMW801 to run smoothly.  Then the Germans changed mixture regulations, plugs, and fuel composition.

I'd wager that the Japanese personnel responsible for maintaining that Zero never had it running better than TAIC did, and likely not even as well.

Based on what?  Your opinion contrary to common sense?

I am merely reporting what the tests revealed, moreover Saburo Sakai told an interviewer that the maximum speed of the A6M2 was just 315 mph.

Please read before you start refuting:

Additionally the conditions of the South Pacific are some of the harshest in the world on mechanical equipment. The humid salty air can corrode metal in a very short time. It was not uncommon for all combatants to lose power on their aircraft after a short period of time in the field under those conditions. You cannot expect any aircraft to be maintained in top condition for very long in primative conditions in harsh enviroments.

I would hardly call a Carrier "primative" conditions and I certainly expect Saburo Sakai to have experienced a drop in performance from the primative island airfields he operated from for much of his IJNAF career.

All the best,

Crumpp

[Angus]

Ok WW3 on the forum...again
Milian (somehow I find your writing familiar....oh, your not ??):
"--------------------------------------------------------------------------------
Terminal Velocity does NOT rely totally on mass.
--------------------------------------------------------------------------------



lol, terminal velocity has everything to do with mass!

normally, in level flight, drag = thrust, at terminal velocity, drag = weight. Typically, at terminal velocity, the prop produces no thrust but an excess amount of drag.


quote:
--------------------------------------------------------------------------------
(Remember the 2 cannonball test from the tower in Pisa as well as the feather and hammer on the moon, - remember Newton)
--------------------------------------------------------------------------------



double LOL. That is NOT mass, that is DENSITY!"



Boulderdash!
Hammer vs feather is mass to mass - on the moon where there is no air. So, the feather falls like the hammer.
The cannonballs have exactly the same shape and are solid through, the mass pr cubic is the same. Their aerodynamic shape is the same. They fall the same. At terminal velocity one might extend - in that case the bigger one, for it has more mass against the frontal area - but there we are again, at an aerodynamic issue.

And Crumpp: I am not sure WTF is going on, but basically you are spending your time on the forum arguing with practically everybody! Even me!!!

[Crumpp]

Furthermore, you seem to think that allied mechanics were just plain stupid. That they couldnt change out plugs, or perform maintenance on an engine (theirs or anybody elses), just because they weren't certified by BMW or Mitsubishi, "wow its a radial engine never SEEN one before Billy".

Spend a nickle and call an aircraft engine mechanic to get his opinion.  Ask him about different fuels and developing full boost.

http://www.motobende.de/

Addtionally get the reports from the PRO or NASM archives on German fuel development, mixture settings, etc....

Funny It seems it took mechanical engineers studying the motor to get the correct mixture and plug combination with this Kommandogerät.  We ran into similar problems rebuilding our Kommandogerät to function properly.  It took much more than Billy Bob on the flightline.

Here is one that the RAE never flew, only bench tested:
 

Unfortunately, BMW changed the Kommandogerät fuel injection system to reduce the harshness of gear change.  The antiknock protection of C3 was also changed putting the RAE right back at square one with their BMW801 engine knowledge because the Kommandogerät operation and plug requirements completely changed.

http://img126.potato.com/img.php?loc=loc246&image=9cc_Alkane_Ratio.jpg

Not to mention the fact that BMW produced six different versions of the BMW801D2 that had completely different motor set ups:

http://img125.potato.com/img.php?loc=loc51&image=05d_different_motors.jpg

All the best,

Crump

[Crumpp]

And Crumpp: I am not sure WTF is going on, but basically you are spending your time on the forum arguing with practically everybody! Even me!!!

Because folks keep posting idiotic ideas to defend the status quo irregardless of the facts.

Such AS:

terminal velocity has everything to do with mass!

Terminal velocity has absolutely NOTHING to do with MASS.  Drag effects it but not mass....

The answer to the question (doesn't a more massive object accelerate at a greater rate than a less massive object?) is absolutely not! That is, absolutely not if we are considering the specific type of falling motion known as free-fall. Free-fall is the motion of objects which move under the sole influence of gravity; free-falling objects do not encounter air resistance. More massive objects will only fall faster if there is an appreciable amount of air resistance present.

Basic physics.....

http://www.glenbrook.k12.il.us/gbssci/phys/Class/1DKin/U1L5e.html

all the best,

Crumpp

[Angus]

Lol that quote was from.....whatever his name is

[Angus]

Ah, yes Milian. (this time)
But Crumpp....you sometimes post something wrong as well and get corrected.....

[Crumpp]

But Crumpp....you sometimes post something wrong as well and get corrected.....

Sure I do.  I am human too and certainly do not know everything.

All the best,

Crumpp

[HoHun]

Hi Widewing,

>I'd wager that the Japanese personnel responsible for maintaining that Zero never had it running better than TAIC did, and likely not even as well.

Hm, probably somewhat off-topic in a Luftwaffe thread, but have a look at the different Allied test results and TAIC estimates I collected and complied into one chart:



Quite obviously, it's impossible that all of the tested aircraft were running at standard (manufacturer guaranteed) performance. I'm not even sure that at least one did.

>Let's go further and understand that TAIC was staffed by some of the Navy's best aero engineers.

Well, the interesting thing about the test results and the TAIC intelligence charts is that as far as the A6M is concerned, the performance reported by TAIC exceeds the performance tested by TAIC.

(Not that I'd suggest using the TAIC performance estimates as final word on the issue - they're often inconsistent in themselves, and in the case of the A6M do not match the TAIC intelligence data on the engines, which in turn has issues of its own.)

A6M performance really is a tough nut, and I don't believe anyone has cracked it yet.

Regards,

Henning (HoHun)