Maneuvering flaps on the P38

[Traveler]

It's not a wish...you should try to read your posts from the point of view of what other people see...it reads like an accusation of intentional error for just a single aircraft, when in reality it's not...all of the aircraft share the same programming consolations incorporated by HTC...I've looked through 51 pages of your posts and I don't see a single post in the Aircraft and Vehicles section where more knowlegeable people tend to address such discussions as you have brought up here. Now if you had posed this and the landing gear issue in that section, you would have gotten some useful information that you could then use to post a legitimate wishlist inquiry that would start with "Can we get the..." or "I would like the..."

As for the 50% at 250mph being a useful setting...that is not a maneuver setting...if you read the POH there was a flap control setting on the flap lever labeled "maneuver" and further investigation reveals that setting limited the deployment to 8 degrees as a "maneuver" setting which was engineered for high speed combat maneuverability and supposedly allowed the P-38s to out turn 109s...the 50% flap deployment was used primarily for take offs on fields with less than ideal conditions for normal take off without flaps (from various pilot testimonials)...in the G model the flaps were reinforced so that the flaps could be deployed to 50% at speeds up to 250mph without damage......there are a whole bunch of people in AH who fly the 109s and would love just 5 degrees of flap over 200 mph.



I'm not a P-38 fan so I'm not going to do all the research for you, but what I have learned from discussions on these boards regarding some similarly perceived irregularities on other aircraft...is that what we want may not always be possible without a lot of work from a small staff of people who do a lot to create as good a product as any available and interact with their customers.

Murdr I believe posted the most authoritative response about maneuvering flaps or combat flaps for the AH P38 flap model.  I’m not sure about your 8 degree solution.  Murdr suggested either the second notch or third notch of flaps as being the closest solution to the ½ flap Combat setting documented in the POH. 

I have seen the 8 degree number mentioned and Ack – Ack offered a digram, however, it would be in direct contrast with the solution offered by Murdr.  I’m also not sure what the original source of that 8 degree diagram is.  What I did see was a document that mentioned that when you select the first notch of flaps in the P38 that the flaps move back and down at an 8 degree angle.    I believe the angle is in reference to the cord line of the wing.

What would be interesting is to know what the square footage is of the flap area represented by the ½ flaps settings in the POH to compare with the flaps in AH for each notch of flaps.

I’ve been looked on line for a document but have found nothing yet. 

My reason for posting in the WishList was because I was making a wish.

[gyrene81]

My primary source is a scanned copy of an authentic P-38H, P-38J, P-38L-1 Army Pilots Flight Operating Instructions manual in PDF format...the rest was obtained by using various search syntaxes on google...a lot of history buffs out there...and some interesting archival info from aircraft museums and former pilots.

(2) FLAPS.—The flaps are a Lockheed modified
Fowler type.

(a) CONTROLS.—Flap action is controlled by
the lever (figure 7-2) on the right-hand side of the
cockpit. When the lever is placed to UP, DOWN, or
MANEUVER, the flaps will automatically stop at the
desired position. The lever should be returned to
CLOSED as soon as the end position is reached. The
control will not go to the DOWN position until the
trigger on the lever is lifted through the notch just for-
ward of the CLOSED position.
Note
When using maneuvering flaps, the flap lever
must be left in the MANEUVER position. If
it is moved even slightly forward and then
returned to MANEUVER, the flaps will ex-
tend completely. (This condition is corrected
on late airplanes.)

The only thing I haven't been able to find is what the actual angle is for full flap deployment on P-38s...there was one hint that the modfied fowler flaps had a 40 degree maximum angle of deployment but I haven't found any military or manufacturing specifications that verify that. The 8 degree maneuver flap setting came from 3 other sources including a pictorial writeup by a former pilot and an aircraft museum website.




Sorry but this is hardly written in the context of "wish":

The flaps are not modeled correctly for the P38 series.  AAF 51-127-1 show the airspeeds and degrees of flap that could be used on the P38, including maneuvering flap or combat flaps that could be use at airspeeds up to 250 MPH.  The first 50% or ½ flaps was considered maneuvering flaps.  The current model has the flaps settings at 20% increments or 5 notches of flap represent full flaps .   With the current model you can’t set ½ or 50% flaps.  You can set flaps at 250MPH but the percentage of flaps is not modeled correctly.

The p38 flaps were actuated with a handle that set the flaps in motion via hydro and electric pump.  The motor was started and stopped by that handle so the pilot could set any value of flap he wished to.  There was a ident stop for ½ flap to help the pilot quickly set combat flaps.

Presently in the current P38 model we are left with just  a 40% setting and thus lose the benefit of that additional 10% in lift and reduced stall speed .  The first ½ flap setting in the P38 provided additional lift and reduced stall speed.  The current flap setting does not model the combat flaps setting correctly.

If the P38 aircraft are modeled correctly then the inability to set combat flaps at 50% puts the P38 driver at a disadvantage. 

A little more like "I'm getting owned in my P-38 and I don't like it...AH is to blame..."

[Traveler]

My primary source is a scanned copy of an authentic P-38H, P-38J, P-38L-1 Army Pilots Flight Operating Instructions manual in PDF format...the rest was obtained by using various search syntaxes on google...a lot of history buffs out there...and some interesting archival info from aircraft museums and former pilots.

I think I used the same PDF as reference.

The only thing I haven't been able to find is what the actual angle is for full flap deployment on P-38s...there was one hint that the modfied fowler flaps had a 40 degree maximum angle of deployment but I haven't found any military or manufacturing specifications that verify that. The 8 degree maneuver flap setting came from 3 other sources including a pictorial writeup by a former pilot and an aircraft museum website.

I'm not sure, but I thnk the 40 degree maximun angle refers to the angle between the cord line of the wing and flap.




Sorry but this is hardly written in the context of "wish":  it really was written in the context of a wish, honest, no hidden agenda

A little more like "I'm getting owned in my P-38 and I don't like it...AH is to blame..."  not really , I'm not a score geek, I don't care when I get shot down or by whom as long as its fun, I donl't complain about HO's or being picked or ganged or killed one on one

[gyrene81]

I'm not sure, but I thnk the 40 degree maximun angle refers to the angle between the cord line of the wing and flap.

That is entirely possible Traveler...I'm betting Stoney or someone like that has some dusty manual laying around to verify it.

gyrene81,

Ki-84 only has two flap positions.  I am sure there are other aircraft that vary as well.

I never noticed that Karnak...guess I never had a reason to drop flaps in that plane before.

[LLogann]

Think of the Brits......... Hurri & Spit with only 1, either down or up. 

I never noticed that Karnak...guess I never had a reason to drop flaps in that plane before.

[kvuo75]

That is entirely possible Traveler...I'm betting Stoney or someone like that has some dusty manual laying around to verify it.




I never noticed that Karnak...guess I never had a reason to drop flaps in that plane before.

have to be pretty slow to get them out, but it can get quite fun against f4u's, 80mph stall fights!

[Traveler]

Badboy provided the following:

If you are trying to do some calculations, increased values of coefficient of lift with the Fowler flaps extended were always based on the area of the basic wing. So if you have Lift and Drag polars for the P-38's Fowler flaps the calculations should be done based on the 327.5 square ft. However, the area of the extended Fowler flaps on the P-38 is 42.6 square ft.

Hope that helps.

Badboy
 
Thanks, so 42.6 square feet divided by ½  is 21.3 Square feet or the amount of flap described by the POH that yields the best benefits of increased lift and reduces stall speed for the Combat or Maneuvering flaps.

In AH that 42.6 square feet is divided into 5 equal segments of 8.52 Square feet each.

Hit the “Q” key one time and you get 8.52 Square feet of flap
Hit the “Q” key again and you have 17.04 Square feet deployed
The third tap of the “Q” key gives you a total of 25.56 Square feet. 
Fourth Notch of flaps provides you with a total of 34.08 Square feet of flap
Fifth Notch of flaps provides you with a total of   42.6  Square feet

So the closest flap setting within the game to the POH recommended combat flaps setting is either the second or third notch.  Which is what Murdr provided in his response.  He suggested the second notch for airspeeds between 225 and 250 and the third for speeds below 225.

[Badboy]

So the closest flap setting within the game to the POH recommended combat flaps setting is either the second or third notch.

The flap positions in the game are at 0, 0.2, 0.4, 0.6, 0.8 and 1.

The 0.5 setting clearly falls between 0.4 and 0.6 the second and third position.

So the area wasn't needed to arrive at that conclusion.

Badboy

 

[Traveler]

The flap positions in the game are at 0, 0.2, 0.4, 0.6, 0.8 and 1.

The 0.5 setting clearly falls between 0.4 and 0.6 the second and third position.

So the area wasn't needed to arrive at that conclusion.

Badboy

  

I  wanted to know what the Square footage of flap area for each flap notch position was.  So I needed to know the total area of the flap.

[hitech]

Gentlemen, you are assuming facts that do not happen in AH.

We simply put the degrees and coefficients in for each flap stop.

So what degree is displayed may or may not match what the real plane displays for degrees for the same coefficients. For instance the first stop of the p38 may be displaying 10 degrees, but really be the 8 deg coefficients.

The only thing degrees really do is control the rate at which the flaps move. We put in a degree per sec rate, and then each flap stops degrees.

HiTech

[FLS]

You waited 4 pages to tell us that?   

It looks so good we get confused. Badboy would you post EM diagrams for all the 38's at all flap positions please?   

[Badboy]

I  wanted to know what the Square footage of flap area for each flap notch position was.  So I needed to know the total area of the flap.

Why?

I already explained you wouldn't need it if you wanted to do lift/drag calculations and you didn't need it for the calculation you presented... So I'm curious what you want it for?

Badboy

[Badboy]

Badboy would you post EM diagrams for all the 38's at all flap positions please?

Yep, here is a current P-38L EM diagram.

It is a bit cluttered, because there are four diagrams in one. Since the first three flap settings were under discussion I've only overlaid the EM diagrams for those positions. The diagram has good resolution but may not display well in your browser, it might be better to download it and display it in a graphics package that will make it easier to read.



This clearly shows the effect of flaps on maneuverability, and you can see that the turn radius and instantaneous turn rate is improved continuously as each notch of flaps is employed. For example, you can see that at 200mph the instantaneous turn rate increases by more than 7dps with 3 notches of flaps and the turn radius drops from over 800ft to below 650ft.

However, you will notice that the sustained turning ability increases with the first and second notch, but then levels off and drops very slightly by the third. This would suggest that over this range of the envelope, the aerodynamic efficiency peaks somewhere between the 2nd and 3rd notch. It is also interesting to note that when the flaps are deflected by one notch, the Ps performance of the P-38 improves at all speeds below 215mph. Which setting you would choose to use in combat, and indeed, if you should deflect the flaps even more, would depend on the situation and type of fight you are in.

But now you can see how the flaps effect the maneuverability of the P-38, you can judge for yourself.

Hope that helps...

Badboy

[FLS]

Thank you Badboy.  Interesting that aerodynamic efficiency peaks where Traveler speculated the maneuver flap setting would be even though HiTech posted that we can't assume that is the 50% position mentioned in the POH.

[maddafinga]

Totally a hijack here, but Badboy, do you have one of these for the K4 by any chance?  No biggie if not, but I'd be interested to study one. 

Thanks.