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Flap settings

W

womblesd

Registered User
O’Fallon, MO
What are the standard flap settings for a super cub? My super cub, rebuilt ground up in 1999, has flap settings of 25 and 50 degrees. Would it be hard to add a 10 degree setting; would such a change require approval?
 
It depends some have 2 some have 3 and some have 4. I have 2 on mine what would you want 10 degrees for?
DENNY
 
That makes sense. It is nice to have easy grab on the flaps. I got short arms so 25 is better for me.
DENNY
 
I’ve flown several cubs with three notches of flaps. I found that I never used the first (10 or 15 degree) notch.

I think Piper got that right. But if it makes you happy, go for it. Not a big deal. Should be a minor alteration.

MTV
 
I use full or zero. Not sure what the other settings do, although we use them for training. And I like to set them on the high side of 50.
 
Type Certificate says 0 to 50 plus or minus 2 degs. I'm thinking they originally had two settings from factory? I remember seeing several that had a 10 and 50 deg. My experimental has 86" flaps and I have settings at 10-20-40-50. I use 20 for most everything, but like the 50 into a short pond, and the 10 is great for slow flight.
 
I filed 2 extra notches in mine. I use to use the first notch to get the handle up where it was easier to reach on take-off. After installing the Trustline Mod I figured out I got off quicker if I left the flaps up until it was ready to fly and then pulled them. I use 2nd and 3 rd notches to climb in the mountains sometimes and Cathy can't pull the 4 th notch with the shortened flap handle and Performance STOL flaps. She has been flying my Super Cub and gets slowed down nice with the 3rd notch of flaps. The two extra notches saved a little weight as well. ;)
 

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Mine came with a 4 notch plate. I don't know who installed it or where it came from. It's second notch is right where #1 used to be and it's fourth notch is obviously full flaps. I only ever use #2 and #4.
 
Somewhere here (didn't search) there's probably some info on degree of flap deflection versus flow separation over the top. More lift than drag at first followed by more drag than lift as the flap is extended. The first of the three would be for some lift, good airspeed, and best sprayer/duster dispersion when applying. The second is for max lift I assume and the last for drag on landing (and Vx according to Piper).

One of Piper's Owner's Manual (https://www.manualslib.com/manual/1019706/Piper-Super-Cub-Pa-18a-150.html see p. 47) recommends the first notch or 1/3 flap at 80 mph for best swath width when dusting.

Gary
 
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BC12D-4-85 said:
The first of the three would be for some lift, good airspeed, and best sprayer/duster dispersion when applying. The second is for max lift I assume and the last for drag on landing (and Vx according to Piper).

Gary
Click to expand...
Keep in mind that the Ag model had a big hopper in the back seat and baggage area which moved the CG aft when loaded. Also the extra lift which is created with flaps moves the center of lift on the wing aft which helps to balance the extra weight in the hopper. So using 10 degrees in an Ag PA-18 is similar to using a little bit of flap in a Beaver on floats.

1/3 flap would be about 16 degrees on a PA-18
 
Let’s get back on topic. My questions have nothing to do with Ag model. Can someone tell me how to source a bracket that has a 10 degree flap setting for the first notch, and would such a bracket require an STC?
 
Plot where you'd like the pawl to stop, remove the arch, cut a ramp using a fine wheel (square shoulder) on a bench grinder, reinstall. That's how I've done my own.
 
Read Post #13. Ask maintenance about alteration. I've also modified stock brackets as noted in #19. File first notch stop to whatever flap angle you want.

The problem with these parts is eventually the pawl end and bracket notches wear and the flaps can retract on their own if bumped. Had it happen and it required a tune up to fix.

Gary
 
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If you really want 10 degrees just file in a notch at 10 degrees because it looks like the AG one is about 1/3 flap. In the long run I don't think the difference between 10 degree or 25 degree preset will matter that much, depending on tire pressure the added lift can reduce tire squat/drag, everything is a tradeoff), the main issue is ease/timing of flap deployment! Soooooooo many factors are involved in a consistent short takeoff and they all interact with each other. As to the question of needing a STC that should be answered by whoever is signing off the annual!!

This has been a very interesting and informative post overall.
DENNY
 
womblesd said:
Let’s get back on topic. My questions have nothing to do with Ag model. Can someone tell me how to source a bracket that has a 10 degree flap setting for the first notch, and would such a bracket require an STC?
Click to expand...

I just filed the notch, see no reason to need an STC.
 
womblesd said:
Let’s get back on topic. My questions have nothing to do with Ag model. Can someone tell me how to source a bracket that has a 10 degree flap setting for the first notch, and would such a bracket require an STC?
Click to expand...
I owned an original 1960 Pa-18/150 that was unaltered and had a notch at 10 and one at 50.
 
The TC says 0 to 50 degs. and doesn't say anything about in between so I don't see the issue with making what you want.
 
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