Flaps usage in real combat

[Brent Haliday]

Some airplanes have information in pilots manuals and/or flight-test data that give flap deployment speeds for different settings of flaps.  My guess is that HTC does not pick flap-deployment speeds arbitrarily but instead based on information they have.

Here's a video of using flaps in one model of 109 -- doesn't look like it would be too easy during a dogfight.  http://www.youtube.com/watch?v=qcMjhihuuX8&feature=player_embedded  In AH, all we have is the keyboard, so it's easier in the game than in real life, but then flaps are restricted to several discrete settings, rather than continuously variable on the 109 that has continuously-variable deployment.

All you need is one "safe" deployment speed/deflection relationship to get the safe force load, from that you can adjust the other variables to match the forceload.  Since the flaps are the same size and the internal structure and mechanics are the same then it would be quite unreasonable to assume that the safe forceload would change.  You could easily do the math if you we're doing lift and drag calculations, and you could cross check your work with published data from other aircraft that have the low deflection deployment speeds in their POH.  After all the forces are the same and the structures are either identical or very very similar.  Better IMO then pretending that if it is not spelled out specifically then it can not be figured out.

[LCADolby]

Me 109 F/G:
"- Did pilots like the slats on the wings of the 109?
Yes, pilots did like them, since it allowed them better positions in dogfights along with using the flaps. These slats would also deploy slightly when the a/c was reaching stall at higher altitudes showing the pilot how close they were to stalling.....this was also useful when you were drunk "
- Franz Stigler, German fighter ace. 28 victories.

I can attest to those slats being useful while drunk!  

[Brooke]

No, full flaps wouldn't even be useful in real life combat. "Combat flaps" however could be achieved with a couple of cranks on that wheel.

Yes, I agree that a little bit of flaps in combat looks possible.

[Brooke]

All you need is one "safe" deployment speed/deflection relationship to get the safe force load, from that you can adjust the other variables to match the forceload. . . .

Perhaps, unless there is data (like on US planes) showing safe speeds at different deflections.  Then you don't need to guess -- you just use the real data.  It is not necessarily OK to assume a flap mechanism can take the same force at different deflections -- so that's one significant assumption you otherwise make -- as how far various parts of the mechanism are extended, moment arms, etc. are going to change as deflection changes.  Also, computing torque on the flaps might not be as easy as you think and thus end up being another significant estimation/assumption.

As long as there is data on what speed that first notch of flaps can be deployed at, that's the main thing; and for that, what matters most is if you can pop them when in a stallturn with flaps up.  So the 109 is fine there.

That's the big disadvantage of some planes -- that you can be doing a stall turn flaps up and not be able to deploy a notch of flaps but have to slow down first (which means weakening your turn to deploy them).  How many planes are in that category?  Maybe the FW 190, the A-20, not sure what else; and they are probably there because of data that says "don't deploy any flaps above X speed".

[icepac]

Angle of incidence is fixed....like with bolts and stuff and can not be changed.  An exception being the F8U Crusader.

I don't mean that the static angle of incidence of the entire wing changes like the f8 crusader but rather that the change of shape of the wing by the flaps changes the angle of incidence which is calculated relative to the fuselage.

[Brent Haliday]

Perhaps, unless there is data (like on US planes) showing safe speeds at different deflections.  Then you don't need to guess -- you just use the real data.  It is not necessarily OK to assume a flap mechanism can take the same force at different deflections -- so that's one significant assumption you otherwise make -- as how far various parts of the mechanism are extended, moment arms, etc. are going to change as deflection changes.  Also, computing torque on the flaps might not be as easy as you think and thus end up being another significant estimation/assumption.

As long as there is data on what speed that first notch of flaps can be deployed at, that's the main thing; and for that, what matters most is if you can pop them when in a stallturn with flaps up.  So the 109 is fine there.

That's the big disadvantage of some planes -- that you can be doing a stall turn flaps up and not be able to deploy a notch of flaps but have to slow down first (which means weakening your turn to deploy them).  How many planes are in that category?  Maybe the FW 190, the A-20, not sure what else; and they are probably there because of data that says "don't deploy any flaps above X speed".

We will need to disagree,  I have confidence that designers of combat aircraft design flight control surfaces appropriately, and knew how to use safety factors.
so IMO the "significant estimation/assumption" would that a structure less exposed to the forces it was designed tested and safety certified to withstand, would get weaker in the process of deployment when as stated it is less exposed to the force it was designed to withstand.  

BTW does anybody know of an overspeed damage report on a fighter flap system in WW2 ?

[Brooke]

We will need to disagree,  I have confidence that designers . . .

OK, but really, what difference does it make?  All that really matters is if you can drop that first notch of flaps in a turnfight or not, and only a handful of aircraft can't.

Do you have any data that a FW 190 could drop 10 deg of flaps at, say, 200 mph instead of 175 (or whatever it is right now in the game)?

If not, are you saying that the FW 190 should be able to drop flaps at 200 mph anyway, regardless of what data says?

[Drano]

If not, are you saying that the FW 190 should be able to drop flaps at 200 mph anyway, regardless of what data says?

I think without actually answering this direct question now at least twice that's exactly what he's saying.

Just sayin! 

[Guppy35]

What it really comes down to is someones favorite cartoon airplane doesn't perform as they believe it should so it must be a modeling problem.

Why not just enjoy the pretend fighter pilot world for what it is.  As I've said before.  This discussion comes up every so often.  More often then not it's really nothing more then a veiled Luftwhine.

[Brent Haliday]

OK, but really, what difference does it make?  All that really matters is if you can drop that first notch of flaps in a turnfight or not, and only a handful of aircraft can't.

Do you have any data that a FW 190 could drop 10 deg of flaps at, say, 200 mph instead of 175 (or whatever it is right now in the game)?

If not, are you saying that the FW 190 should be able to drop flaps at 200 mph anyway, regardless of what data says?

FYI the 190 has no speed warnings for it's maneuver, flight, or take off settings, which like the 109 were also not fixed for a specific degree of deflection BTW.  Just an over and under speed warning for the landing fully deployed setting.

  So the question is, do you guys have any data saying it can't deploy 10 degrees of flap safely at a higher speed than it can safely deploy them at 60 degrees?

So I think that most other operators did not feel a speed warning for low deflection flap settings were a very big concern.  Much like guppy's pilot accounts suggesting the same thing.  

As far as missing data goes, did anybody find an overspeed flap damage report or account or anecdote yet?

[Brooke]

FYI the 190 has no speed warnings for it's maneuver, flight, or take off settings, which like the 109 were also not fixed for a specific degree of deflection BTW.  Just an over and under speed warning for the landing fully deployed setting.

  So the question is, do you guys have any data saying it can't deploy 10 degrees of flap safely at a higher speed than it can safely deploy them at 60 degrees?

I don't, but are you saying that no pilot's manual or flight-test document says "don't deploy flaps if you are faster than X"?

So I think that most other operators did not feel a speed warning for low deflection flap settings were a very big concern.

If a document says "don't do X, or things will break" then doing X is unwise, and I can't fault a simulation for either precluding X or having things break if you do X.  If doing X won't break things, then documents generally don't say "don't do X".  That would be silly.

Much like guppy's pilot accounts suggesting the same thing.  

No, those are pilots flying planes that clearly have the ability to deploy flaps at higher speeds, designed into them on purpose (contrary to most aircraft).

[GScholz]

In the 190 there were three flap positions available:  Retracted, take-off (13 degrees) and landing (58 degrees). The flaps were electrically actuated and the pilot selected flap positions with push-buttons in the cockpit.



As for 109s using flaps in combat here's an anecdote from a Pony driver named John C. Meyer on May 12, 1944:

"In about a turn and a half, I was on his tail. Then he dropped some flaps, unlike other Huns, who in similar situations have broken for the deck and set themselves up and I was unable to get sufficient deflection. This Jerry continued his tight turn and seemed very willing to continue the fight. I tried dropping ten degrees, then 20, of flaps and although this helped momentarily to decrease the radius of the turn, my airspeed dropped off so much that nothing was gained by this."

[Brent Haliday]

I am Pretty sure the 190s flaps were +/- several degrees (maybe 7 degrees either side of) 11 or maybe 13 degrees for the flight setting.  They were adjusted and set per load out and pilot preference by the ground crew.
I am not sure whether the landing setting could be adjusted from the 58 degrees and I am also not
Sure that no buttons depressed was the fully retracted setting giving the 190 two low deflection options in flight.
I am also wondering if at some point they were hydro deployed and maybe electronically controlled. 
Te 190 was very different internally mechanically.  Probably part of the reason captured examples performed so poorly compared to operator testing.

Brook I think the problem lies in the different definitions or interpretations of what x means.  The 190 poh discusses flap settings with several names only ascribing landing to the 60 degree setting.  Then only specifies speed warnings for the landing setting one do not exceed and one do not go below.  So in the case of the 190 do not do x is only talking about 60 degrees not the other settings.  As you yourself have noted there is a suspicious hole in the flight envelope where airflow is such that some flaps are required yet unavailable because of speed restrictions.  I ask you sir, have you ever heard of that being a noted issue in the real world accounts of the 190 pilots?

[Brooke]

Brook I think the problem lies in the different definitions or interpretations of what x means.  The 190 poh discusses flap settings with several names only ascribing landing to the 60 degree setting.  Then only specifies speed warnings for the landing setting one do not exceed and one do not go below.  So in the case of the 190 do not do x is only talking about 60 degrees not the other settings.  As you yourself have noted there is a suspicious hole in the flight envelope where airflow is such that some flaps are required yet unavailable because of speed restrictions.  I ask you sir, have you ever heard of that being a noted issue in the real world accounts of the 190 pilots?

I haven't, but flaps usage the way we commonly use them in the MA was not common in real life.  I have read some accounts of LW flying ("The First and the Last", "JG26:  Top Guns of the Luftwaffe") as well as lots of accounts from allied side and don't recall any specific mentions of flap usage by LW pilots.  I only recall a few (maybe 5 or less) from the allied point of view.  So, I'm not sure not having heard of it means it wasn't an issue.

My contention is that HTC picked flap deployment speed based on some statement and not on their belief.

Is the "landing configuration" (full flaps) deployment speed in the manual you have the same as the first-notch deployment speed in AH (something like 175 mph), or is it lower than that?

[GScholz]

There is a cluster of buttons just just aft of the throttle. On the left side there is a row of three buttons; one for each flap setting: Retracted, take-off, and landing. The two buttons to the right in that cluster are for the landing gear (also electrically actuated). To the immediate right of the cluster is a flip switch that controls elevator trim, with the trim indicator in front of it at to the right of the throttle. At the very bottom of the picture you can see the landing gear indicator lights.