Flaps, flaps, & flaps.

[bunch]

Originally posted by niklas
nice image. Let´s consider it based on some measurments though they write drag estimations.

It confirms what i said about the drawbacks of a fowler:
- It has the highest lift
- It has much more drag than a split or plain flap
this can be seen by the L/D value, which is equivalent to cl/cd . Becaue the fowler has approx. 50% higher Cl value, with same value of Lift to drag the CD (drag coefficient) must be also 50% higher than that of a plain or split flap!!!!! And i bet at lower deflections the plain and split flap have way better L/D values!

- the pitch down moment
The fowler has by far the highest momentum coefficient Cm. Imagine: in a 4G turn your weight is 4 times higher, thus the moment due to the backshift of COL!! you have to compensate this by your elevator, in case of a fowler i doubt that you are strong enough at 250mph!

But P-38 in AH are ridicolous anyway, even without flaps they already have lift coefficients of over 1.6....  Though you never should forget that wing area includes the area covered by the body and engine cells, and a twin fighter has three intersections where no lift is actually produced. So effective wing area is lower, what in turn means that when you base the lift on effective wing area the corresponding lift coefficient without flaps of the P-38 in AH is probably 20% higher than for any other fighter lol.
Lol you can hang 70° banked in a turn below 150mph with flaps that has nothing to do with reality.

niklas

Propwash over the wings produce lift Lol
Lol Propwash over the rudders increase rudder authority Lol
Lol you write one side of the issue when you obviously know both lol
Lol eat less bacon, read more lololololololololololololoolo lloloo
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[niklas]

Propwash - upwards on one side, down on the other. Don´t overestimate the influence. Turbulent airflow in any case.
Oh and i measured the Cl with engine power as low as possible.

But ok, propwash explains everything in case of the P38 in AH, and Baron Münchhausen didn´t lie when he got out of the sump by pulling on his own hairs as we all know...

niklas

[Crumpp]

The line has to be drawn somewhere, and very clearly. And that line, as HTC sees fit, is the flight manuals. Crumpp's being mentioning 109s or 190s using flaps upto 400mph, except there's currently no real documented technical evidence that it's possible - and that's why I can't support it. I'd love to see it, but if the planes I like must remain under its documented limits, there is no ther way.

We can start with the 109:

But ok, propwash explains everything in case of the P38 in AH, and Baron Münchhausen didn´t lie when he got out of the sump by pulling on his own hairs as we all know...

That's the standard line the P 38 fans through out.  The CLmax for the P38 is pretty unremarkable according to the NACA.  

http://naca.larc.nasa.gov/reports/1946/naca-tn-1044/index.cgi?page0036.gif

All the best,

Crumpp

[Ack-Ack]

Originally posted by Crumpp


That's the standard line the P 38 fans through out.  The CLmax for the P38 is pretty unremarkable according to the NACA.  


All the best,

Crumpp

Standard line of the P-38 fans?  Care to elaborate?


ack-ack

[Crumpp]

Standard line of the P-38 fans? Care to elaborate?

I have heard that line given many times Ack-Ack.  Twin-engine aerodynamics has some unique properties.

 A propeller creates thrust by accelerating a large mass of air.  Those portions of the wing located directly behind the propeller, are exposed to this accelerated air, and as a result
create more lift than those portions exposed only to the free flow of the atmosphere.

http://www.globalsecurity.org/military/library/report/1985/TMC.htm

The P 38's CL max is certainly on the low side in spite of this phenomenon.  Granted induced lift is more pronounced at low speed. I imagine it puts the CL max with the flaps down at around average to slightly below average for a WWII fighter.

All the best,

Crumpp

[Ack-Ack]

Originally posted by Crumpp
I have heard that line given many times Ack-Ack.  Twin-engine aerodynamics has some unique properties.

 

http://www.globalsecurity.org/military/library/report/1985/TMC.htm

The P 38's CL max is certainly on the low side in spite of this phenomenon.  Granted induced lift is more pronounced at low speed. I imagine it puts the CL max with the flaps down at around average to slightly below average for a WWII fighter.

All the best,

Crumpp

Heard what line many times?   It is true that the lack of torque is one of the reasons for its gentle stall characteristics and can also aid the Lightning in a slow speed fight against a plane with torque in AH.  In the reported duel betweel Lowell and a Spitfire pilot, Lowell used a maneuver called the "Cloverleaf" that took advantage of the lack of torque on the P-38 to get an angle on the Spitfire at low speeds because due to torque at the speeds they were fighting at, made it difficult for the Spitfire to gain an angle on Lowell.  The Lightnings lack of torque also aids it in it's vertical ability since it doesn't have to waste E fighting torque as it zooms up.  So yes, you can say that the lack of torque on the P-38 does have some benefits over planes with torque.


ack-ack

[TimRas]

Originally posted by niklas

But P-38 in AH are ridicolous anyway, even without flaps they already have lift coefficients of over 1.6
niklas

Niklas, Crumpp,
If you are claiming that the lift coefficient is wrong, then the (clean) stall speed of the the AH P-38 must be wrong too ?

[Ack-Ack]

Stall speed of the P-38 was 75mph IAS and once in a stall it was very gentle and extremely easy to get out of.  


ack-ack

[niklas]

IAS is not TAS at higher AoA IAS, TAS is always higher. You only can offer the pilot an IAS value because that is the only value he can read from his instruments, but TAS is higher, especially if you do it in a kind of little zoom like in all those zeno videos (lol they knew why they did it that way...And of course every aircraft has a very gentle stall, strange, they were all trainings videos for newbies, maybe it was mentioned so often to give them confidence and take their fear away? I can´t remember a single high speed stall demonstrated in those videos.... Didn´t some P-38 fell out of the sky during manoevers at airshows btw ???)
Even flaps out can influence the airflow so IAS is way off from TAS. External ordinance can change IAS too (FockeWulf mention it)!

niklas

[Ack-Ack]

Ummm...I think I know the difference between Indicated and True Airspeeds. Someone asked what the stall speed was and I gave the answer in indicated air speed, since that is the speed measurement I use when I fly.  External ordnance can also influence TAS since it's adding drag, not just IAS.  


And I really do hate to burst your bubble (well, maybe not) but the P-38 did have a very gentle stall characteristic and that's an undisputable fact.  And that gentle stall characteristic was helped by having no torque to contend with.  For example, the stall characteristics of the P-38 is far better than the Spitfire.


Enjoy...


ack-ack

[MENDEZ]

wow i have just read this whole thread and have stinging eye sydrome:eek:  I think im going to become a 38 jock as you guys put it. I 've been impessed by how pellik shots me down with so much ease 479th

[Crumpp]

What is the aircraft configuration for that stall speed?

All the best,

Crumpp

[BUG_EAF322]

Wait guys when u are in ma im gonna threaten u to punch and bash and challenge to the DA.

I hate arrogant P38 drivers.

Look at my charts they show it so clearly.


The p38 suks and every threath about it im gonna say the word, Just as Kurt Tank does every day he speaks to me and im his chosen one.

torque and fowlerflaps don't have anything to with fligh charistics.

A 2000HP single engined planes flys just as easy as a cessna 172.

And training movies where pure propaganda

Im not paranoid

P38 drivers are just cheaters and HTC just got it wrong.

all the best( i really mean that)

[Crumpp]

Lets look at some typical fighter CLmax's under various conditions:

P51D in high speed flight in various altitudes:

http://naca.larc.nasa.gov/reports/1951/naca-tn-2525/index.cgi?page0013.gif

http://naca.larc.nasa.gov/reports/1951/naca-tn-2525/index.cgi?page0014.gif

http://naca.larc.nasa.gov/reports/1951/naca-tn-2525/index.cgi?page0015.gif

http://naca.larc.nasa.gov/reports/1951/naca-tn-2525/


F6F Hellcat in landing configuration and level flight clean condition:

http://naca.larc.nasa.gov/reports/1948/naca-tn-1639/index.cgi?page0020.gif

http://naca.larc.nasa.gov/reports/1948/naca-tn-1639/index.cgi?thumbnail11#start


In all honesty, the CLmax of the P38 in landing configuration is just plain average to below average for a WWII fighter.  Given it's other aerodynamic characteristics I think Dean's assessment in AHT is dead on.

SOME expert pilots could get a very tight turn out of the P38 by using it's stall characteristics or asymmetrical power.  Your average pilot could not hope to turn the plane that well. Even with flaps down the P38's turn rate was at best average for a WWII fighter.  It was outstanding that a twin engine fighter could even come close to single engine performance and the P 38 is the only fighter to hold this distinction.

All the best,

Crumpp

[Widewing]

Within the prespective of the game, the P-38 is more than a match for the Luftwaffe guys.

Let's look at the P-38J, a mid 1943 aircraft versus all the 109s, 110G-2 and 190s.

P-38J has 68 kills of the 109F-4 and has been killed 43 times.

P-38J has 43 kills of the 109G-2 and has been killed 27 times.

P-38J has 75 kills of the 109G-6 and has been killed 48 times.

P-38J has 265 kills of the 109G-10 and has been killed 245 times.

P-38J has 339 kills of the 110G-2 and has been killed 122 times.

P-38J has 93 kills of the 190A-5 and has been killed 75 times.

P-38J has 156 kills of the 190A-8 and has been killed 108 times.

P-38J has 255 kills of the 190D-9 and has been killed 226 times.

P-38J has 41 kills of the 190F-8 and has been killed 9 times.

Overall, the P-38J has a 1.47:1 K/D against the entire plane set. That's pretty dang good among non-perked fighters.

Looking at the P-38G (my favorite), we see a 1.15:1 K/D against the plane set, which is very good considering this is a mid 1942 fighter.

As for the P-38L, it fares poorly compared to the other two, and not because it is in any way inferior. It's primary use is as a bomb truck, due to hauling 2k in bombs and 10 rockets. Most of the hooples flying the L on "stupidcide missions" exist about as long as a gnat's fart and couldn't fight their way out of a retirement home restroom anyway. As a result, the P-38L shows a 0.73:1 K/D.

I enjoy the P-38s, they are certainly capable.

My regards,

Widewing