Flaps, flaps, & flaps.

[Crumpp]

"MANEUVERING FLAPS SHOULD BE EXTENDED ONLY LONG ENOUGH TO COMPLE PARTICULAR MANEUVER AND THE BE RETRACED IMMEDIATELY"  

Is exactly what Lockheed says.

http://www.jamesreese.org/hangarflying/Issue6.htm

Prolonged usage had a detrimental effect on turn performance.

Is absolutely true as with any flap.

loss of maneuvering options with the loss of speed

All effect turn.  As you lose speed you lose angle in the bank.  As your bank decreases your turn radius increases.

All the best,

Crumpp

[Ack-Ack]

Originally posted by agent 009
Well here's a turn question. Which would outturn which betwen a Yak 3 & a Tony. I know, hard to figure. below 350, the Tony could outturn MK 9 Spit.

You can compare the performance of the Ki-61 to that of the bf109E or the C.202.  When the Ki-61 was first seen by U.S. pilots some pilots reported them as "bf109Es with Japanese markings flown possibly flown by German pilots", while some others reported it as the C.202.  It wasn't until the Allies finally got their hands on a crashed Ki-61 that these two myths were laid to rest.


ack-ack

[Murdr]

Just to clearify, Lockheed test pilot Ray Meskinmen said "MANEUVERING FLAPS SHOULD BE EXTENDED ONLY LONG ENOUGH TO COMPLE PARTICULAR MANEUVER AND THE BE RETRACED IMMEDIATELY"

Crumpp said "Prolonged usage had a detrimental effect on turn performance."

If Ray Meskinmen would have said "LOOK BOTH WAYS BEFORE CROSSING THE STREET".  Crumpp would be arguing that your eyesight would go bad for failing to follow the directions on how to use your eyes.  In either case, the warning pertains to exterior factors.  

I have seen a 38 pilots describe his 360 deg, under 90mph turn for a victory on a george as a "controled stall".  In that particular instance, that 38 pilot said he would never have tried that if there wasnt only 2 of them and 12 of us.  Pilots like McGuire often got into slow speed dogfights despite the fact that he preached otherwise to his subortanants.  While most fighters have to contend more and more with tourque as speeds decline, the 38 with its counter-rotating props does not.  Appearently that is "nothing special".  While it wasnt the reccomeded, or even the smartest tactic, the 38 could do it when called upon.

[Crumpp]

Torque has nothing to do with it.  It's just the science of how planes fly, Murdr.  


The P 38 is not exempt from physics, no matter how much you want it to be!!

As Lockheed says:

"MANEUVERING FLAPS SHOULD BE EXTENDED ONLY LONG ENOUGH TO COMPLE PARTICULAR MANEUVER AND THE BE RETRACED IMMEDIATELY"

All the best,

Crumpp

[dtango]

Regarding the loss of speed due to flaps and effect on turn performance, I was trying to make clear in an earlier response care needs to be taken on how the aerodynamics is characterized.

Use of flaps does not automatically mean a loss of airspeed that reduces the turn performance of an aircraft.

The case is only true if the turn (typically a sustained turn) bleeds more energy than can be made up by the power-available of the aircraft.

The case exists where with flaps extended you are able to fly the aircraft where Power-Available=Power-Required to maintain a sustained turn with higher turn rate & lower radius only achievable with maneuver flaps deployed (Ps=0 curve on an EM plot).  

Planes like the P-38 with a large excess power-available margin have a broader range of the flight envelope where this case exists.

Tango, XO
412th FS Braunco Mustangs

[Crumpp]

Planes like the P-38 with a large excess power-available margin have a broader range of the flight envelope where this case exists.

Where does the P 38 have more of an excess of power than most WWII fighters?


The flaps will raise the CLmax, power available stays the same EXCEPT more is needed to overcome the additional drag at low speeds.

This is exactly why Lockheed recommends the flaps be used for short periods of time.  Same goes with any manuvering flap.

"MANEUVERING FLAPS SHOULD BE EXTENDED ONLY LONG ENOUGH TO COMPLE PARTICULAR MANEUVER AND THE BE RETRACED IMMEDIATELY"

http://www.jamesreese.org/hangarflying/Issue6.htm

Use of flaps does not automatically mean a loss of airspeed that reduces the turn performance of an aircraft.

True.  In the case of the P 38 Lockheed warns both in writing and in film that use of flaps does rob speed in the P -38.

Don't be caught with your flaps down for any length of time in combat; the reason being that with maneuvering flaps down you can unknowingly get down to such low speeds that all the power in the world won't do you much good should you need sudden acceleration.

Loss of speed = decrease in bank and subsequent loss of turn radius.  

All the best,

Crumpp

[agent 009]

Hi Humble. Basing it on an article I read by Clive Killer caldwell. Tony was 1st Japanese plane at or near 400 mph. also 1st one to give US planes some competition in the dive.

 on Japanese planes are often way off. George for example according to Sakai was over 400 mph. but it is almost always listed at much less.

[Murdr]

Wow, time for the strawman review so quickly?  Must be some kind of record.

You attributed your own statment as a representation of what is stated in a specific publication from Lockheed.

I politely pointed you to the reference that you couldnt locate.  Without addressing the validity of your attributed statment, I pointed out it was not specifically representative of what was stated.

You replied with a direct quote from said publication, followed by quotes from posts.

I replied in clearification so that the casual reader did not misinterprate which quote is from which source.  Made a saterical comment.  THEN went on to touch on points of discussion by others in the thread.

You replied with material supporting the validity of your original statment, which if you were paying attention I did not attack in the first place.  Simualtaniously ignoring my point regarding low speed stability relative to 0 net torque vs + net torque, in similar fasion of ignoring Meskimen's caviot regarding not getting so slow that you cannot accelerate out of trouble when needed.

[Crumpp]

There is no strawman, Murdr.  You tried to point out with nothing except your desires  how you want the P 38's flaps to work.

The quotes are from Lockheed.  The science is from aerodynamics.  

Simualtaniously ignoring my point regarding low speed stability relative to 0 net torque vs + net torque, in similar fasion of ignoring Meskimen's caviot regarding not getting so slow that you cannot accelerate out of trouble when needed.

Torque has nothing to do with the discussion on sustained turning with the maneuver flaps extended.  Your desire to be able to fly around in tight little circles with your maneuver flaps down for extended periods of time without penalty is contrary to the instructions put out by Lockheed and aerodynamics.

The key was do the maneuver flaps drop the airspeed.  According to Lockheed, YES they do.  The flaps are to be used for short periods of time to complete a maneuver.  Leave them down and your airspeed goes.

All the best,

Crumpp

[Murdr]

Originally posted by Crumpp
There is no strawman, Murdr.  You tried to point out with nothing except your desires  how you want the P 38's flaps to work.

Oh yea? Where is the quote of me from this thread to support that?

[dtango]

Where does the P 38 have more of an excess of power than most WWII fighters?

 
Let's be clear.  I never said it had more excess power than MOST WW2 fighters.  However you can get a gauge of excess-power-available by the max rate of climb performance of an aircraft, the P-38 being one of the best in this aspect for US aircraft.  Aircraft like the bF109-G10 & G6 like we have in AH are similar in terms of having a large excess-power-available margin.
 
Your statements are all true for given part of the flight envelope, but only for given parts of the envelope.   You need to remember the other parts of the performance envelope.  
 
The recommendations from Lockheed etc. are all good but don't address the case where you fly a sustained turn with no energy/speed loss.  Their assumptions are for given conditions where you continue to bleed energy.

The flaps will raise the CLmax, power available stays the same EXCEPT more is needed to overcome the additional drag at low speeds.

Assuming you're flying:
     (a) in a sustained turn
     (b) at CLmax
 
yes you will have more induced drag to overcome (low speed itself doesn't cause the additional drag).  The question is how much and what impact it has on turn performance.  

There is a point where you can fly at sustained turn CLmax flaps extended where power-available equals power-required.  Yes you might have a marginally lower turn rate vs. clean configuration but because of the lower airspeed achievable to maintain flight your turn radius is significantly reduced.

Tango, XO
412th FS Braunco Mustangs

[Crumpp]

yes you will have more induced drag to overcome (low speed itself doesn't cause the additional drag). The question is how much and what impact it has on turn performance.

Exactly.  Facts are Lockheed says in the case of the P 38 do not do it.

Why?

Power available will have a hard time overcoming drag.  This means the drag of the flaps was close too the minium power required for level flight.  Your not going to be able to a turn very tight when your power available is expended just maintaining level flight.

I would say it's a safe scientific bet that turn radius is effected in the P38.

Don't you think Lockheed would have told their pilots to keep them down if it was not detrimental to performance?

I certainly do not see them holding back performance enhancing "secrets" or giving out bad advice to their end users.

Looks to me like they were intended to be used for short periods of time to gain gun solution and quickly retracted as Lockheed recommends.

All the best,

Crumpp

[Ack-Ack]

Originally posted by Crumpp
Your desire to be able to fly around in tight little circles with your maneuver flaps down for extended periods of time without penalty is contrary to the instructions put out by Lockheed and aerodynamics.


Crumpp

Crumpp show one post by Murdr or myself that states that in this thread?  In fact, show a post in any thread where Murder and I advocate that.  Have fun searching because you'll never find one.  Why is it that when we happened to discuss flaps or the P-38 you and Kweassa get all bent out of shape?  No offense, but you and Kweassa are just pulling things out for the sake of argument without any substance to it.  

So let's recap, here are the facts:

1) Majority of P-38 pilots did use their flaps while in combat, not just an "elite" few like Kweassa suggested.


ack-ack

[Crumpp]

I have seen a 38 pilots describe his 360 deg, under 90mph turn for a victory on a george as a "controled stall". In that particular instance, that 38 pilot said he would never have tried that if there wasnt only 2 of them and 12 of us. Pilots like McGuire often got into slow speed dogfights despite the fact that he preached otherwise to his subortanants. While most fighters have to contend more and more with tourque as speeds decline, the 38 with its counter-rotating props does not. Appearently that is "nothing special". While it wasnt the reccomeded, or even the smartest tactic, the 38 could do it when called upon.

An attempt to justify continious flap usage.

BTW, a stall will greatly increase you turn radius as the aircraft is no longer flying the turn vector.  Watch the P38 handling video.  Best turn is achieved at CLmax, as dtango points out.  Drop off on the backside of the lift curve and you are no longer at CLmax.

All the best,

Crumpp

[Murdr]

Originally posted by Ack-Ack
Why is it that when we happened to discuss flaps or the P-38 you and Kweassa get all bent out of shape?  

O, me, me, pick me.

Because, we use them in the same manner in which they were sometimes used in combat, and its not fair because the USAAF, and McGuire, and Lockheed said not to, and their German engineers didnt give them the same ability.