p38 dive recovery flaps revisited

[df54]

 

   1- auto trim  -
  off
   2- manual trim-set for straight and level flight 
   3- dive flaps extended.

   No pitch up. Everything i have read states that with dive recovery flaps extended the nose would pitch up 10 to 15 degrees. Is this correct. If so why not in ah flight model

[Ack-Ack]

The dive flaps are modeled correctly for the P-38L in AH.  Search for previous posts on this subject matter.


ack-ack

[Tordon22]

It's only like 8 posts down.

-Zap

[Traveler]

 

   1- auto trim  -
  off
   2- manual trim-set for straight and level flight 
   3- dive flaps extended.

   No pitch up. Everything i have read states that with dive recovery flaps extended the nose would pitch up 10 to 15 degrees. Is this correct. If so why not in ah flight model

Dive flaps on the P38 when extended or when retracted have no effect on pitch as far as I can tell.  I there is a change in pitch when extending wing flaps, there is a noticeable change in pitch when wing flaps are extended or retracted.   

[Ack-Ack]

Dive flaps on the P38 when extended or when retracted have no effect on pitch as far as I can tell.  I there is a change in pitch when extending wing flaps, there is a noticeable change in pitch when wing flaps are extended or retracted.   

There is also a nose up pitch when using the dive flaps. 


ack-ack

[Guppy35]

Cartoon P38G pilots don't need dive flaps!

[Widewing]

There is also a nose up pitch when using the dive flaps. 


ack-ack

The problem, ack-ack, is that most guys deploy the recovery flaps after they are already too fast and too low or worse, in auto-trim. Assuming they are in manual trim, a 4g pull-out needs at least 4k altitude at 500 mph. So, they still auger.

What ack-ack says is true, the recovery flaps work as they should, but you need to be in manual trim and you need to get them deployed prior to the onset of buffeting so that you begin the pull-out before you go faster than 500 mph.


My regards,

Widewing

[Ruah]

I thought the P38 Dive breaks were similar to those on gliders - that pop up and disrupt airflow over the wing - slowing it down.  I know that the air-breaks finally allowed P38 pilots to chase after german planes who used to escape from 38s through steep dives. . .

[Delirium]

I thought the P38 Dive breaks were similar to those on gliders - that pop up and disrupt airflow over the wing - slowing it down. 

Those dive brakes were dive flaps, a completely different animal.

The dive flaps on the 38 were designed to maintain elevator control, without them, in a high speed dive the air would move away from the tail and limiting control surface authority.

[Ack-Ack]

LOL!  df54 still doesn't believe they work, so he's posted on the Ubisoft/IL2 forums instead.  What is even funnier is that most on that thread have no clue about the P-38.  One guy claims the L didn't have dive recovery flaps, another guy claims that they acted like speed breaks at low altitude.  Even Crumpp throws in his two cents (and as usual is incorrect).

quote:
With all sue respect to the AH people they are inherently wrong, no need to check history books, just a logic check; if the plane does not pitch up or does not slow down then how does it recover?


It depends and IIRC this is covered in the P38 POH.

If you put the dive brake down first and then dive, there is no pitch up. You never reach compressibility and without a configuration change we have no pitching moment.

If you enter the dive and then put down the brake you will get a pitching moment.

All the best,

Crumpp

Only one person in that entire thread seems to have a clue and the rest just don't seem very bright.

[Stryker]

The dive flaps are modeled correctly for the P-38L in AH.  Search for previous posts on this subject matter.

if so, why do i still go into compressibility with the flaps down in the L? even diving with the throttle back

[Ack-Ack]

if so, why do i still go into compressibility with the flaps down in the L? even diving with the throttle back

Because you're not deploying them at the correct time.  There is nothing wrong with the dive flaps, if anyone has issues with the dive flaps, it stems from operator error.


ack-ack

[OOZ662]

LOL!  df54 still doesn't believe they work, so he's posted on the Ubisoft/IL2 forums instead.

Why'd you have to post that, Ack-Ack? Being a link, I inherently had to click on it...now I feel such pity for the WWII world.

[Delirium]

if so, why do i still go into compressibility with the flaps down in the L? even diving with the throttle back

The dive flaps aren't a guarantee against compression either, even without throttle nose low the 38 is going to pick up speed real fast. Try cross controlling/side slipping in addition to diving... if you find yourself compressing often, you need to re-examine how you are flying the 38.

[Mar]

I don't do much research, however I do know a little about the 38L's dive flaps. They were never designed to slow down the plane, only disrupt airflow where it was thought to be the most compressablility occuring so that airflow over the tail could be restored to a point that the plane could pull out of a high speed dive.

There is always the possiblility that I'm wrong, but they don't act any other way in the game either.