• If You Are Having Trouble Logging In with Your Old Username and Password, Please use this Forgot Your Password link to get re-established.
  • Hey! Be sure to login or register!

Flaps: How much is too much?

Jeff Pralle

Registered User
Alaska
Always been curious what others think and where the limits are and why. I have most of my time in stock wing cub and ext wing 12. Re-Building a Super Pacer on the old Simpson STC from James Smith in Washington. She had Extended wings and 116” of flap... Thoughts?
 
Jeff,
As your probably well aware of " long wing cubs" that have NOT had the ailerons moved out are not a winning combo in Xwinds. Lots of folks now compare the new 5' much WIDER, 'Performance flaps' are similar in performance, to the old 7.5' "Sullivan" Cub standard width flaps.......
Something to consider: instead of just ' going long' it's really about square inches
of the deflected surface. The math says a
6.5' flap that is 2" WIDER than standard width has more total sq inches, than a 7.5' flap that's standard width...... So you may want to consider wider?? Something like the D&E flap/aileron kit for your trailing edge stuff?
If the Piper engineers knew the 8.5' ailerons were the correct lenght, for a standard Cub wing, adding ribs to create outboard lift will certainly require modified
Ailerons to compensate for that.
There have been LOTS of Alaskan Cubs with extended wings 'rolled up into a ball'
For this very reason........
All the best on your project!
E

Sent from my moto e5 go using SuperCub.Org mobile app
 
Last edited:
we have HUGE fowler flaps and slats on our BCSC REV2 and it changes the way you fly, I am able to do a full circuit at less than 30kt IAS and at no point does the aircraft feel unsafe.
BUT..... it DOES change the way you fly, you can't just climb into a fowler flapped aircraft and fly the same circuit as you did with a flapless plane, the big flaps affect your elevator effectivity....differently at different CofG and weights, it strongly affects your flare and energy management during your approach and flare, it changes the way you actually touch down and the "feel" when you touch down, it affects the way your aircraft reacts to crosswinds (not necessarily making it less effective it just behaves differently).

so all of these things need to be taken into consideration and the aircraft flown accordingly.
I love having the huge flaps
 
we have HUGE fowler flaps and slats on our BCSC REV2 and it changes the way you fly, I am able to do a full circuit at less than 30kt IAS and at no point does the aircraft feel unsafe.
BUT..... it DOES change the way you fly, you can't just climb into a fowler flapped aircraft and fly the same circuit as you did with a flapless plane, the big flaps affect your elevator effectivity....differently at different CofG and weights, it strongly affects your flare and energy management during your approach and flare, it changes the way you actually touch down and the "feel" when you touch down, it affects the way your aircraft reacts to crosswinds (not necessarily making it less effective it just behaves differently).

so all of these things need to be taken into consideration and the aircraft flown accordingly.
I love having the huge flaps


Well stated. I have flown alot of different piper wing mods and combinations. Just most of my time is stock ag model as a guide in AK. Over 3500 hrs most off airport in Alaska. I have always been a fan of light stock cubs.

I do have about 800 hours in a 12 with extended wings without the ailerons moved out. I will not install that mod as a mechanic for a customer. It was a contributing factor to a 35 mile walk home...

I do not have the option in this plane to do the slotted flaps and stay certificated in the US.


I have access to a PA-14 with ext wings ailerons moved out and 8’ flaps. Sullivans STC. It flies quite nicely. I do notice a pitch down when full flaps are deployed. Lowering the deck angle in this way is huge on short rough strips. Question is can this be accomplished with a longer flap at fewer degrees of deployment? Increasing wing camber throughout more of the length and creating less drag? Or is it a function of the big barn door dragging creating the pitch change?
 
One can always use a lower notch of flaps for times you don't want it all out there, (early Cessna 150's with 40 degrees of flaps in winds as an example). When you do want to elevate down into the end of a strip over an obstacle, having all that stuff hanging out is a great thing to have.

Watching the fowler flap planes work, I believe my next cub will have that set of flaps on it!
 
Always been curious what others think and where the limits are and why. I have most of my time in stock wing cub and ext wing 12. Re-Building a Super Pacer on the old Simpson STC from James Smith in Washington. She had Extended wings and 116” of flap... Thoughts?

I fly a Super Pacer with SC length ailerons moved out. And, I have 90 inch flaps. The advice I got when building mine was to not install the large flaps and use SC ailerons. I'm happy with my set up. It has excellent slow speed handling, 50 mph approaches are easy.
 
Back
Top