'nuther 3 inches/IB ext. Flaps

Comments on flaps extended inboard to the fuselage??

Performance increase value?

Turbulence over the tail?

Dave Calkins.

My cub has lots of mods and most are useful but without a doubt, the extended flaps were a bad mistake.

I can feel the turbulence over the tail feathers when I pull the last notch of flaps and it takes a lot more stick for control. Worse yet, if I have to dive into a short LZ over obstructions, I can never get the tail back down, which decreases braking and increases roll out.

I would say this mod stinks. It's coming off my cub at the first opportunity.

Thanks for the input Cubdriver.

There must be someone else who has something to say, too?

Dave Calkins.

A flap extension (cut piece of alum....looks about .040) that was attached to the inboard flap rib with screws was on my a/c when I got it. To me there is not any noticable advantage or disadvantage. I need to get a calm day and try it with and without them.

cubdrvr, the extension I'm talking about doesn't look any different than a stock flap except for the flap is a few inches longer. The wing-root fairing is modified to end at the trailing edge of the wing, and the little stub fairing-support that sticks off the fueslage gingerbread is cut off.

Are talking about something like this, or some type of temporary piece of aluminum? I'm having a hard time picturing from your description.

Let me know what you're talking about.

Damn, I guess now's the time to finally get that digital camera I've been eyeing!

Dave Calkins.

I'll get a pic on later.....going to chase pheasants in ND next week.
It's just a flat piece of aluminum about 12" X 8". The outboard edge of this piece is screwed onto the bottom inboard side of the flap. This extension is adjacent to the fuselage and rear window when down and rests up against the wing root fairing when retracted.

Flap Extension.

Hi Cubdriver. I think you are going to be in for a big surprise when you take off the extensions. The key to me is "when I pull the last notch of flaps ". If you have a otherwise stock Cub you have only two notches of flaps. The first notch creates about equal lift and drag. The last notch "Full Flaps" creates only drag. (Spell that turbulence). The extension does increase the pressure differential across the flap, that's why we do it. But removing the extension will not put your tail in clean air. Mr. Piper wanted a fast and easy fairing. It takes time (money) to fit a flap tight to the fuselage. That was not in line with his production line theory. Jerry.

X

TESTING

I like the idea? Never even thought of doing it that way? Always saw the flap extension done by splicing on another spar/rib section as described?

I was thinking it would be a great benifit to my PA12 as perhaps it would lower the deck angle (at full flaps)??

Any comment Jerry or S2D?

Tim

It's amazing to me, that an extension being just screwed on like that would stay on. I would think it wouldn't last very long. If I'm understanding this correctly, you're just taking a flat piece of alum 040 and screwing it to the inboard rib on the flap and it extends under the wing root fairing to the fuselage??
Brian

David M. Calkins said:

cubdrvr, the extension I'm talking about doesn't look any different than a stock flap except for the flap is a few inches longer. The wing-root fairing is modified to end at the trailing edge of the wing, and the little stub fairing-support that sticks off the fueslage gingerbread is cut off.

Click to expand...

Yep, that is it exactly. It really stinks!

I bush a lot, in extremely tight places. Since I had the extensions installed, I have experience both ways with no other changes to my cub. My flaps are 3 notches and the first two aren't too bad but grab that last notch any you had better have a plan.

I'm begging you, don't screw your cub up with this crummy mod.