Whats the max angle for flaps?
12-17-2009, 07:07 PM
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Whats the max angle for flaps?
I have a 60 size Top Flite P-47 that I really need to slow down to land on my clubs short grass field, I have a pretty bad approach too...alot of tall trees at the end of runway so I need to clear trees then drop altitude fast..I've heard the max angle for flaps is 45 degrees, what are you guys opinions?
12-17-2009, 08:41 PM
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RE: Whats the max angle for flaps?
Bugaloob,
Max flap angle depends on what you are trying to achieve, lift or drag. It will vary from one wing design to another. Your info. about 45 degrees is that on most airfoils, beyond 45 degrees you are only creating more drag and no aditional lift. Example is a WWII dive bomber that had flaps deployed to 90 degrees in the dive. I would think you could use more than 45 degrees to increase drag, but you need to experiment by adding a little at a time. At some point beyond 45 degrees, you are going to start decreasing total lift. Try it at altitude until you find the angle that works best for the lift/drag you're looking for.
Paul
Max flap angle depends on what you are trying to achieve, lift or drag. It will vary from one wing design to another. Your info. about 45 degrees is that on most airfoils, beyond 45 degrees you are only creating more drag and no aditional lift. Example is a WWII dive bomber that had flaps deployed to 90 degrees in the dive. I would think you could use more than 45 degrees to increase drag, but you need to experiment by adding a little at a time. At some point beyond 45 degrees, you are going to start decreasing total lift. Try it at altitude until you find the angle that works best for the lift/drag you're looking for.
Paul
12-18-2009, 09:05 AM
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RE: Whats the max angle for flaps?
Something else to consider is spoilers instead of flaps - although they can be tricky to use.
Spoilers will decrease lift, so your plane will drop without gaining speed.
A good analogy of this is a glider. With a glider, you only get one shot at landing, so the trick is - you stay higher than you want to be on approach, then you deploy spoilers. Spoilers "spoil" the lift, so the plane sinks without gaining speed (as it would if you just nosed it down).
Once you are at the proper height, you retract the spoilers and settle in.
The only problem with using spoilers on a model is that on landing, your fingers are pretty well occupied, so it is difficult to retract them when you need to.
Spoilers will decrease lift, so your plane will drop without gaining speed.
A good analogy of this is a glider. With a glider, you only get one shot at landing, so the trick is - you stay higher than you want to be on approach, then you deploy spoilers. Spoilers "spoil" the lift, so the plane sinks without gaining speed (as it would if you just nosed it down).
Once you are at the proper height, you retract the spoilers and settle in.
The only problem with using spoilers on a model is that on landing, your fingers are pretty well occupied, so it is difficult to retract them when you need to.
12-23-2009, 10:07 AM
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RE: Whats the max angle for flaps?
On a very clean plane you want the drag as well as the lift. The Spit. had about 80 deg. flaps. On my old Yellow Cap 10B you could come across the threshhold at about 10 ft. 200 ft down the runway, you were at about 5 ft. and only 100 ft left. With flaps you could touch down in about 100 ft. past the threshhold. This has about 60 deg. flaps.
Gord.
Gord.
