View Full Version : Flap Angle

11-03-2010, 01:30 AM
In preparation for covering my Back Country Cub project I installed the wings and rigged the flaps and ailerons. The flaps are 40 degrees when fully extended. This seems adequate as they are 80 inches long. Just curious how some of you other builders are rigging your flap angles. If I file another slot in the ratchet I can get 52 degrees.

Thanks for the replies,

Bill Rusk
11-03-2010, 07:07 AM

File that extra notch. The advantage is that it will allow you to operate further behind the power curve. That last notch is pure drag but useful in certain circumstances. Operating in this zone is not for novices or the faint of heart. If you are satisfied with a standard Supercub there will be no need for 50 degrees of flaps but if you are truely into extracting every last possible ounce of performance that is one of the tricks. Hope this helps and good luck.


11-03-2010, 07:50 AM
I agree with Bill about the advantages of the extra flap angle, especially if you have 160 or 180 hp available.

If you also plan larger tires, you might want to consider how the flap/tire combination might affect your pitch control if your elevators are stock size and set at factory up/down limits. With a forward cg, you might have landing flare issues.... with a rear cg you might have stall recovery issues.

The area along the fuselage of prop wash, deep flap and tire turbulence disturbs a lot of air that your stabilizer/elevator needs for good pitch control.

11-03-2010, 08:08 AM
You may want to fly it a while and make this decision later.

11-03-2010, 08:33 AM
The Maule maxes out at 48* just fyi...

11-03-2010, 09:27 AM
My flaps are set to 82 degree's standard flaps lengthened to fuse two inch cord extension outside fence on flap landing speed 26mph before 24mph these are gps speeds at 1100ft alt runway Mikeo

11-03-2010, 10:02 AM
Not sure where you like your seat but if on most forward notch I would check if you can get the flap handle that far back.

I am set around 48 or so at max but have 77" flaps. Keep in mind some of that goes away when all the cable slack is taken up. Look out the window sometime when at full flaps. Make sure you remove as much slack as possible, even a slight bias where they pull down a bit at rest doesn't hurt. I am thinking about welding on a slighty longer arm to my flap handle to get it over 50. Then again, I might just leave it as good enough. I am starting a scratch build Travel Air now and should probably quit tinkering.

Dave Calkins
11-03-2010, 10:49 AM
Anyone interested, get all the flap deflection you can, and learn to fly it. You will get slower/shorter landings, for sure.

Flying "behind the power curve" is a skill we all should acquire, or at least wish to acquire. If you don't know, fly with a buddy or instructor who does............you have a lot to learn, and all good stuff.


11-03-2010, 11:17 AM
I am starting a scratch build Travel Air now and should probably quit tinkering.

My kit has 50. To quote a very experienced Cub pilot when I asked him about this he said: "You can't have too much flap angle, the more the better." and for the reasons others have mentioned; operating behind the power curve at slower speeds. One of the reasons he liked 35" tires over 31" too - more drag.

So Bugs, which model Travel Air? How about a model 6000?

11-03-2010, 11:23 AM
So Bugs, which model Travel Air? How about a model 6000?

No, biplane! 4000! ;)

11-03-2010, 01:12 PM
Christian, Are you going to have a website?

11-03-2010, 01:51 PM
I am going to register travelairproject.com, if it is anything like supercubproject.com, it is worth a million dollars!

11-03-2010, 02:03 PM
Ha, ha! Maybe!

Christian, Are you going to have a website?

I am going to register travelairproject.com, if it is anything like supercubproject.com, it is worth a million dollars!

Gordon Misch
11-03-2010, 11:09 PM
Pretty sure PA-18 TCDS says 50 deg, +- 2 deg.

mike mcs repair
11-03-2010, 11:17 PM
Pretty sure PA-18 TCDS says 50 deg, +- 2 deg.

yes, but standard length....

the long -12 flap stc lists 40

Gordon Misch
11-03-2010, 11:28 PM
Ah, I see. I'm using standard -18 flaps on my -12, so set them at 50. Thanks for the clarification, Mike.

11-04-2010, 06:07 AM
My flaps are 86" and a little longer chord than standard. I set them up for 10=20=40=and 50 degrees, and have never been sorry. I agree that the longer flaps and the deeper settings require greater attention to use, but the performance is worth it, and slow flight at 10 deg. is a real pleasure. I use a modified 160 and it is certainly adequate for my use.

11-05-2010, 12:52 AM
Thanks for the replies, I appreciate all the information. I was able to rig my flaps @ 10, 24, 43, and 52 degrees after filing a 4th notch in the rachet. Starting to cover now using the Stewart system, so far so good.

bob turner
11-05-2010, 01:47 AM
I have flown a Cub with 60 degree extension. It flew fine, but was outside the type certificate. A well known rebuilder readjusted it for 35 degrees max, which left the cables so loose they looked like they were going to swap pulleys. I tightened them up to the high end of Piper specs, and all is well. I truly liked the extra flap - I think that limited flap is what makes the Husky not as good as the Cub.

11-05-2010, 09:47 AM
Looks good Randy, Where are you doing that? I'd like to see it one of these days. And I'd like to see the Stewart system. I know if (or when) we ever recover the -14 I'd like to use Stewart.

More flaps must be better. And if you don't need it, you don't have to use that last notch.

King Brown
11-09-2010, 06:49 PM
I'm a wuss! Generally, for 95 per cent of pilots, 40 degrees is all that's needed. When it's gusty, jinking all over the place, landing generally into strong winds , a lot of flap blanks tailfeathers and isn't needed. Hanging on the prop behind power curve works wonderfully for the other five per cent who do it every day. Using a lot of flap without a lot of experience isn't recommended.

11-09-2010, 08:42 PM
glad somebody said it.