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3ra_DSLam
04-24-2004, 08:37 AM
I've read that pilots had a button that engaged dive flaps and they used it before entering the dive...is this true? in AeP I use it when I need it, but usually at the end of the dive when compressibility appears.

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http://www.p-38online.com/dive.html

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3ra_DSLam
04-24-2004, 08:37 AM
I've read that pilots had a button that engaged dive flaps and they used it before entering the dive...is this true? in AeP I use it when I need it, but usually at the end of the dive when compressibility appears.

Last sentence of this link:

http://www.p-38online.com/dive.html

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JG7_Rall
04-24-2004, 11:26 AM
Interesting...never knew that

I guess if you want a slower dive with control all the way through it you should engage them before diving. But you can still engage them safely after compressibility and pull up fast enough. Also, dive flaps tend to pitch you up, so I don't know how great that'd be for diving.

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3ra_DSLam
04-25-2004, 01:39 AM
From the pilot handbooks:

"DIVE RECOVERY FLAPS
The airplane without these flaps becomes very nose heavy and starts to buffet above diagram dive speeds (Dia.2.). The dive recovery flaps which are installed under the wings between the booms and tile ailerons restore the lift to this portion of the wing and thus cause the uncontrollable nose heaviness to occur at a higher speed. The flaps also add some drag to the airplane which in conjunction with the higher allowable dive speed permits safer dives at a much steeper diving angle. The dive recovery flaps should be extended before starting the dive or immediately after the dive is started before a buffeting speed has been reached. If the airplane is buffeting before the dive recovery flaps are extended the buffeting will momentarily increase and then diminish. With these flaps extended, the nose heaviness is definitely reduced but the diving speed should never be allowed to exceed the placard by more than 15 or 20 mph. With the dive recovery flaps extended before entering the dive, angles of dive up to 45 degrees may be safely accomplished. Without dive recovery flaps extended the maximum angle for extending dives is 15 degrees. Diving characteristics are better with power off than power on."

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Tully__
04-25-2004, 02:54 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by E111_DSLam:
Better with power off? http://ubbxforums.ubi.com/images/smiley/blink.gif

http://www.sarriacity.net/dslam/imagenes/DSLam2.jpg <HR></BLOCKQUOTE>

Gravity is a very powerful force for heavy aircraft http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif

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|CoB|_Spectre
04-25-2004, 05:41 AM
I've been flying the 38 a great deal lately (mostly all online co-op) and favor the L-model for the obvious benefit derived from the dive flaps. I don't have a rigid criteria for when I use them (before the dive vs during the dive), but I look at them, and all flap settings, as a tool to extract the performance you need for the particular situation. They can be used like wheelbrakes-for-the-airborne when you need to slow down to stay out of compressibility, to keep from overshooting an adversary or reducing speed quickly to shorten your landing approach. The pitch-up that initially comes with the dive flap extension can be used to more rapidly bring the nose to where you want it (i.e., on a target, away from the ground, etc). I have found extended dive flaps to exacerbate stalls, so now the first thing I do when hard maneuvering leads to a stall is to ensure the dive flaps are retracted before initiating stall recovery. I have used the dive flaps on many occasions to save my bacon from impacting terrain as well as getting out of the way of a firing bandit on my six. I've always viewed flaps, whether regular or special use types such as dive flaps, as secondary flight controls to be employed for greater control over your airplane. Judicious use of the dive flaps (sometimes just bumping them quickly out, then back in) will add significant maneuvering capability to the P-38L, not just for anti-compressibility.

worr
04-25-2004, 05:46 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by E111_DSLam:
I've read that pilots had a button that engaged dive flaps and they used it before entering the dive...is this true? <HR></BLOCKQUOTE>

Yes. They would engage it before the dive. This was as a precaution.

Worr, out

3ra_DSLam
04-25-2004, 05:58 AM
No Tully, gravity affects the same way everything. It's inertia; momentum against "air" that gives heavy planes the advantadge in not loose so much speed, but acceleleration is the same (unpowered) 9,8m/s each second.
thx for the answers, didn't know about deploy way of dive flaps...

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Aaron_GT
04-25-2004, 09:34 AM
" Diving characteristics are better with power off than power on."

Better with power off?
Salute!"

It probably means that you are less likely
to go over the placard speed so quickly with
power off. This assumes that you want to lose
altitude quickly, I suppose.

Most WW2 prop fighters have a level acceleration
of around 1 to 3 m/s/s so gravity is a bigger
acceleration.

In terms of dive, a=F/m, where F=mg+T-D where
D is drag, T is thrust fromthe engine. So a=g-T/m-D/m. Bigger things tend
to have larger drag, but less drag per unit
mass. (For a sphere of constant density,
drag scales with surface area, or r^2, and
mass with r^3, so D/m scales as 1/r. For
non-spherical planes it's going to be a little
different of course :-)).

lil_labbit
04-25-2004, 10:01 AM
Well if you're that interested in the p38 http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif
Try this link:

http://www.zenoswarbirdvideos.com/P38.html

There's a 35 minute instruction video for P38 there http://ubbxforums.ubi.com/infopop/emoticons/icon_biggrin.gif and loads of other stuff.

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Abbuzze
04-25-2004, 11:02 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by E111_DSLam:
From the pilot handbooks:

"DIVE RECOVERY FLAPS
Diving characteristics are better with power off than power on."

Better with power off? http://ubbxforums.ubi.com/images/smiley/blink.gif
Salute!

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Where ist the problem?? The solution is "characteristics" nothing mentioned about performance, lower speed in a dive means- better handling thats it!

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