Flight model: Asymmetric flaps

[maus92]

I got jumped in the Snapshot last night by a Pony that I - and everyone else apparently   - did not see.  Thank god I was running film...  Anyway, the Pony inflicted some rather serious damage: engine, left landing gear and left flap.  So basically I had to ditch.  I spotted a field, and attempted a landing.  Unfortunately, I had not checked what systems were damaged, being distracted from that task by trying not to compress the 109G, and still make it to the field.  I deployed flaps and gear, and slipped it down.  In my haste, I went for the grass - hoping to roll onto a hard surface.  But that was not to be.  I snapped off the remaining gear and skidded just shy of the runway.  So,  if I deployed only 1 flap (the other being shot off), why didn't my plane go wildly out of control?  Or react somehow negatively to the asymmetric lift?

And could I add a squeak about considering a forced landing within the confines of an airfield a ditch?  Doesn't make too much sense to me

[Shuffler]

Maybe the flap was stuck partially down.

[maus92]

The film shows the entire flap gone.  And all the pieces flying off during the act of jumping.

[Ghastly]

So,  if I deployed only 1 flap (the other being shot off), why didn't my plane go wildly out of control?  Or react somehow negatively to the asymmetric lift?

Because you were able to use the aileron to counterbalance the difference in lift between the wings.  Remember, the point of using flaps (or similar devices) is to "reshape" the wing to decrease stall speed, not because it generates "tons" of extra lift. If you'd gotten slow enough to stall the wing missing the flap, you'd have had your "wildly out of control" moments.

And could I add a b**th about considering a forced landing within the confines of an airfield a ditch?  Doesn't make too much sense to me

HTC has to draw the line somewhere! If they included the whole airfield, it would be "I was 10 feet off".  If they gave the 10, it would be "I was 2 ft away from where I landed before"  etc. Personally, I think there should be another category that accounts for damage to the plane, since parking the front half of a fuselage on the pavement really isn't a success, even if the pilot is still alive.  Until then, calling the pavement the only "successful" landing is fine with me.


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[CAP1]

So,  if I deployed only 1 flap (the other being shot off), why didn't my plane go wildly out of control?  Or react somehow negatively to the asymmetric lift?

Because you were able to use the aileron to counterbalance the difference in lift between the wings.  Remember, the point of using flaps (or similar devices) is to "reshape" the wing to decrease stall speed, not because it generates "tons" of extra lift. If you'd gotten slow enough to stall the wing missing the flap, you'd have had your "wildly out of control" moments.

And could I add a b**th about considering a forced landing within the confines of an airfield a ditch?  Doesn't make too much sense to me

HTC has to draw the line somewhere! If they included the whole airfield, it would be "I was 10 feet off".  If they gave the 10, it would be "I was 2 ft away from where I landed before"  etc. Personally, I think there should be another category that accounts for damage to the plane, since parking the front half of a fuselage on the pavement really isn't a success, even if the pilot is still alive.  Until then, calling the pavement the only "successful" landing is fine with me.


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i'm not so sure about that. flaps add a LOT of drag once they're past 20 degrees. it's very hard to compensate for that.

[BrownBaron]

You were probably compensating for the missing flap with alieron, or trim. No problems there. The real problem with flaps is if you have them down at any angle, and one is shot off, the plane will behave as if the flap is still on the airframe and in that position, even if you raise the remaining flap. Very annoying little quirk.

[maus92]

I remember my flight instructors drilling into to me that asymmetrical flap condition will make your good day bad.  Thankfully I've never experienced it in real life.

[Ghastly]

i'm not so sure about that. flaps add a LOT of drag once they're past 20 degrees. it's very hard to compensate for that.

And since he was ruddering it into a slip, he didn't notice that he was compensating for the asymmetric drag with the rudder as well.

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[maus92]

Ok, now the brain is storming (or is it the effects on the current tornado warning in my county?)  Anyway, how about HiTech creating a modeling tool where you could simulate various abnormal conditions, all in the safety of an offline world?  Or create another flight test arena where fledgling aerospace engineers can experiment with building bizarre airplanes with WWII era tech to fight each other?  OK, my hunger is making me delusional.  Dinnertime.

[Plazus]

Remember, the point of using flaps (or similar devices) is to "reshape" the wing to decrease stall speed, not because it generates "tons" of extra lift.

Please clarify this statement. I do understand about flaps reshaping the wing. However, flaps DO create lift, right? (I know, not a "ton")

Lets also remember that there are different kinds of flaps: slotted, fowler, etc. The interesting thing about fowler flaps is that it not only increase lift, it also increases the wing surface area, and decreases wing loading by a small percentage.

[BrownBaron]

Great idea. I've been meaning to get my 6 bladed prop powered 109 off the drawing board. Needles to say, it's turbine engine will be suplemented with twin Jumo jets mounted under either wing. There will also be MK 108's. Lots of them, which lob shells with the flat trajectory of .50 cals.

[Ack-Ack]

I remember my flight instructors drilling into to me that asymmetrical flap condition will make your good day bad.  Thankfully I've never experienced it in real life.

If your flaps weren't deployed when they were damaged, you're not going to experience any issues as long as you don't lower the remaining flap.  If you deploy the remaining flap you will experience asymentrical lift and your plane can become very hard to control and keep in level flight.  As long as the remaining flap's position is in the same position as the other flap when it was damaged, you'll be okay. Raise it and it will as your instructor says, a good day gone bad.

ack-ack

[CAP1]

Please clarify this statement. I do understand about flaps reshaping the wing. However, flaps DO create lift, right? (I know, not a "ton")

Lets also remember that there are different kinds of flaps: slotted, fowler, etc. The interesting thing about fowler flaps is that it not only increase lift, it also increases the wing surface area, and decreases wing loading by a small percentage.

most flaps will create lift only until they hit 20 degrees. once you go past 20 degrees, they will also create drag. get to 40 degrees, and it's like having a pair of barn doors hanging off of your wings.

 i think shuffler nailed it......the damaged flap may have been partially down.

 my only experiences with damaged flaps ingame have been in my p38j, and they've usually been out when they got damaged. that makes for a fun time when it's time to extend and reset the fight.

[Karnak]

I've had a Ki-84 get a jammed flap when it was fully deployed.  Made it almost impossible to fly due to the asymmetric flaps.  I couldn't go slow enough to lower the other flap, though I don't recall if that was due to not being able to maintain control as the speed lowered or due to enemy activity forcing me to keep my speed up.

[Ghastly]

What I meant was that the primary purpose of flaps is to change the aerodynamic shape of the wing in such a manner that it is capable of sustaining a higher a angle of attack before stalling, and as a result maintain flight at a lower speed than otherwise would be possible without stalling.  The flaps increase drag and increases the coefficient of lift but the design criteria is to lower the stall speed of the aircraft.

How much difficulty the asymmetrical lift is going to cause is going to depend upon the aircraft design - I'm sure in real life as well as in the sim. 

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