Strange P-40 stuff

[Widewing]

I've seen some guys mention that the AH2 P-40s can deploy their flaps (first notch) at 350 mph.

One might think that is rather fast, but the reality of it is that the P-40s, specifically the P-40E (actually tested) can deploy flaps at much, much higher speeds than that.

FLS and I tested the P-40E in the TA and discovered the following:

At 3,000 feet, you can deploy flaps to the first setting at 422 mph TAS/398 mph IAS.

Diving from 15,000 feet, leveling at 8,000 feet flaps deploy at:

1st setting: 440 mph TAS
2nd setting: 320 mph TAS
3rd setting: 265 mph TAS
4th setting: 215 mph TAS
Full Flaps: 198 mph TAS/171 mph IAS

Note that the P-40's pilot's manual states that max speed for full flaps is 140 mph IAS at any altitude.

We also checked deployment of the 1st setting at 16,000 feet, which was 450 mph TAS/341 mph IAS.

The above is something that needs to be looked at.

Also, when taking off from a 20k field in the TA, full throttle produces just a 2" increase in MAP from idle (from 10" to 12"). If you let the plane slowly roll, when it attains 5 mph the MAP jumps to 34". You can engage WEP to get 34" MAP to get rolling sooner. However, once rolling, even at 5 mph, you can disengage WEP and maintain 34" MAP. That should be looked into as well.

In addition, I cannot find any reference to a War Emergency Power rating for the V-1710-39 engine in the P-40E. As far as I can determine, WEP capability did not arrive until the V-1710-73 engine in the P-40K. P-40Ns also had a WEP rating.

My regards,

Widewing

[Debonair]

Was there anything on the pre-WEP P-40s like the wire gate on the throttle that early Spitfires had?

[HoHun]

Hi Widewing,

>1st setting: 440 mph TAS
>2nd setting: 320 mph TAS
>3rd setting: 265 mph TAS
>4th setting: 215 mph TAS
>Full Flaps: 198 mph TAS/171 mph IAS

That looks quite realistic if you compare it to Messerschmitt data from a graph sheet titled "Me 109E - Zulässige Geschwindigkeit in Abhängigkeit vom Klappenausschlag - nach Jocher 25.7.40" ('Me 109E - Permissible speed in dependence on flap deflection - according to Jocher 25.7.40').

I'm quoting the "n = 6" ('6 G') and "n = 0" curves here.

Flap deflection - 6-G speed - 0-G speed
10° - 770 km/h - n/a
20° - 474 km/h - 490 km/h
30° - 356 km/h - 360 km/h
40° - 292 km/h - 298 km/h

I don't know the exact angles of flap deflection for your P-40 data, but even your relative interval widths follow the same pattern as for the real-world Messerschmitt data, so your P-40 data looks good in my opinion.

>In addition, I cannot find any reference to a War Emergency Power rating for the V-1710-39 engine in the P-40E. As far as I can determine, WEP capability did not arrive until the V-1710-73 engine in the P-40K. P-40Ns also had a WEP rating.

A friendly P-40 researcher who dug into the Australian archives suggested that 44" Hg @ 3000 rpm were the maximum for the standard V-1710-39, though I have found a mention of 45" Hg, too. (For the P-40N, the maximum appeared to be a more generous 57" Hg.)

Regards,

Henning (HoHun)

[DiabloTX]

Well, this begs the obvious question, why in God's name would someone feel the need to deploy flaps at 350kts other than to avoid terminal dive speed?

[TimRas]

Hohun, I think WW's point is:

Originally posted by Widewing
Note that the P-40's pilot's manual states that max speed for full flaps is 140 mph IAS at any altitude.

From a 109 thread:

Originally posted by Pyro
I'm not sure where it came to be thought otherwise, but our flap speed standard has always been based on the figures attained in the pilots manual whenever possible.  It has nothing to do with where the flaps would really be damaged because that's beyond knowing for most planes

[Reynolds]

NNNOOOO!!!!! PLEASE DONT MAKE MY P-40 HARDER TO FLY!!!

[gripen]

I'm not sure if flaps give any real advantage at high speeds because the flaps tend to give nose down effect and maneuverability might not be limited by lift but other limits like pilot's ability sustain acceleration, elevator authority, structural limits etc.

Maybe braking the speed is most noticeable effect.

gripen

[Reynolds]

Originally posted by gripen

Maybe braking the speed is most noticeable effect.

gripen

Thats what I use them for. To ditch speed. fast.

[DiabloTX]

Originally posted by Reynolds
Thats what I use them for. To ditch speed. fast.

In a P-40, do you really think that's a good idea?  I guess in extreme situations but in that particular plane, given a situation, speed is everything.  It least that's how I flew it.

[Reynolds]

Originally posted by DiabloTX
In a P-40, do you really think that's a good idea?  I guess in extreme situations but in that particular plane, given a situation, speed is everything.  It least that's how I flew it.

Emergency landing at a capped field.

Pilotwound, no ammo, several kills. The quicker I lose speed, the quicker I land, and the sooner I get out of harms way with a few more perk points than can otherwise be expected.

[bj229r]

It (1 notch flaps) seems to me that it makes do a split S faster---argh, I hope that wep isnt gonna be removed...E cant compete with a spitV in EA as it is-- the only advantage it has is MARGINAL higher speed

[Widewing]

Originally posted by bj229r
It (1 notch flaps) seems to me that it makes do a split S faster---argh, I hope that wep isnt gonna be removed...E cant compete with a spitV in EA as it is-- the only advantage it has is MARGINAL higher speed

The first P-40K-1s were visually indentical to the P-40E, they just had a more powerful engine. Later, about 500 P-40Ks (-10 and later) were built with the extended rear fuselage seen on the P-40N series. On the P-40K-5, Curtiss introduced a dorsal fillet to the rudder to improve low-speed stability in the longitudinal axis.

Therefore, all HTC has to do is redesignate the P-40E as the P-40K-1.

That, and adjust the P-40B's speed and acceleration... It's currently modeled more like the heavier P-40C, which had revised internal fuel tanks, more armor and provision for a single drop tank (but, not a bomb).

With just 10 hp less, and 800 lb lighter, the P-40B was a bit faster than the P-40E. Likewise, the P-40C was 400 lbs heavier than the P-40B and had the added drag of the fuel tank shackles.

My regards,

Widewing

[Krusty]

P40s are first generation models for AH. It's a given that they have very buggy flight models compared to the remodeled p51s, spits, 47s, 109s, etc.

No doubt they will receive detailed bug fixes and updates as they are "remodeled", as will the ki67s, the d3as, and all the other "first generation" models we have.

[Treize69]

Hopefully when they get to the P-40s they'll add the P-40K and P-40N while improving the B (rename it C?) and E FMs alongside the visual upgrades.

[Col. Flashman]

Not only would I like to see the P-40 Performance Specs & Handling Capabilites revised to the Proper & Historically Accurate ones, but I'd also wish that All Models be represented.

They operated best between Sea Level  & 15,000', around 350mph IAS, performance started badly falling off above this Alt.,  w/o the Supercharger that the Brass Hats had removed.

P-40 no armour or self sealing fuel tanks w/ 2 50s & 4 30s.
P-40B engine upgrade, 1st of the armour & outside coated self-sealing tanks 1/2 way through production.

P-40B/C hybred 100 air frames w/o engines purchased by the Chinese Gov., that the Brits didn't want, for the AVG, as these had Hand fitted Engines because of being out of assembly line specs, placed in storage. These were then Ballanced/Blue Printed & Ported/Polished giving them a Major boost in HP & why the AVG did so well against the Nips outside of the Tactics used.

P-40C engine upgrade, more armour & the 1st of the inside coated self-sealing fuel tanks.
P-40D engine upgrade, heavier, 1st w/ 50 Cals wing mounted, 4 total
P-40E engine upgrade, heavier, 1st w/ 6 50s
P-40F engine upgrade, heavier, experamented w/ wing mounted 20mms
etc.

I'd also like to see the incorperation of Historical Battle Field Mods on the B & E models, such as what some of the FEAF pilots did to thier ships in the Philippians fighting the Nips starting in Dec. of '41 through May of '42.

I've researched WWII Pursuit Ships & Fighters for over 30 years & read thousands of Pilot Combat Reports & those Pilots Personal Statements regarding these A/C, as the Models of most of the A/C flown here are nothing close to the actual Performance capabilities.