Found another cub.

Yup, if I build one it would be that way with needle bearings Pete, I’m a lover of smooth controls.

Jim and I stopped out this afternoon to look at a few things, and sure enough if we were musical we could probably pluck a tune on the aileron cables. Had to pull up the floor to find the turnbuckle but I’ll back that off a touch and see if I can disengage the pulley-friction-wing-leveler. Pretty confident that will make it 80% better.

For fun I measured the flaps. Full range down was about 60 degrees, and I had set them about 50.
I reset them to 36 degrees so there will be less buffering now, and the midstep at 17.

Probably from that buffeting it sounds like there is some broken stitching on the stab’s, so I’ll have to address that too.

Jim thought it was a worthwhile purchase, but wasn’t ready to trade straight up for it. Lol.


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Farmboy said:

For fun I measured the flaps. Full range down was about 70 degrees, and I had set them about 60.
I reset them to 50 degrees so there will be less buffering now, and the misstep at 20.

Click to expand...

Just send me the pictures for more detail as I believe that I see your buffeting problem. The fix is easy. And it has nothing to do with the flap deflection. Mine go down 56 degrees with no trace of a buffet.

Good for you! Can’t wait to see her!


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Farmboy said:

On another note, I have electric flaps operated by a three button switch pad

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My guess is that this allows you to keep your shoes on to count positions?8):lol::lol:

Now, if you were a true cub pilot, you would add a 4th position to separate the second and third:-?

How about a picture of you flying this beautiful plane? Suspect you would have more fun than working on it!!

RaisedByWolves said:

I see no problem at all with another white and red airplane with big tires

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Isn't that why all the Cubs in Montana are painted the same? Funny how much Hartman gets around.

Will do Pete.

Not much flying yet George. Big X on the strip due to mudseason, and need to address the few important issues before exploring more of its personality.


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I saw a couple of X's last week, but they were on top of tractors near a barn at Uncle Eaton's.

keep us posted!

Congrats, Peter! Looks great!

sj

Tore apart some things today, adjusted the aileron cables, scoped the engine, checked the valves, put the big boy sneakers on. It's a start.

Are brake pedal arms available in different widths between brake pedal and cable arm, or do most just build to suit? More so with the left one, but my shoe does not fit between the brake pedal and the arm, so as I push on the left rudder, you can watch the brake pedal move because the outside of my instep is catching the bolt/nut/cable/top of arm. It appears as though these are quite narrow if my memory serves me right.

Pete,

Here's some flap photos for you.

Flap 2

Full down.

This is all that's coming though. Invalid Attachment specified. If you followed a valid link, please notify the administrator

Try posting in a different manner or send an email.

Brake issue: https://www.youtube.com/watch?v=in1eK3x1PBI


your attachments are invalid. Maybe that is just directed at me?:???:


Hope it all are simple fixes, exactly how big of shoes did she get?

aktango58 said:

Brake issue: https://www.youtube.com/watch?v=in1eK3x1PBI
your attachments are invalid. Maybe that is just directed at me?:???:
Hope it all are simple fixes, exactly how big of shoes did she get?

Click to expand...

How do you know if my attachments are invalid or not Mr. Tango...?
Just teenage sneakers - My Twenty-Nines that I had trained over the last couple years.

I guess I'm special. The photos look fine to me. 8)

Couldn’t see them on the desktop, saw them on Tapatalk. Maybe the gap seal on the bottom is messing with it. Normally on cubs it’s on the top and almost touches the flap


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Farmboy said:

View attachment 42056 View attachment 42058

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Thought so! See that gap seal fairing on the bottom of the wing ahead of the flap? TAKE IT OFF! A Cub doesn't go fast enough for this to make any improvement in cruise speed which is the only reason for it.
Then, on the Piper drawings there is shown a "gap seal" which I call a fairing or a streamlined trailing edge (since it only seals when the flap is up) which extends the top camber of the wing back until it touches the top of the flap. At that point it is bent at a sharp angle forward following the curve of the flap forward a couple of inches down into the trailing edge cove section of the wing. There must be a smooth lazy S shaped curved flowing path from the bottom of the wing to the trailing edge of the gap seal where it touches (not quite you don't want it to chafe the fabric) the top of the flap. I used a strip of teflon tape along this edge on the bottom trailing edge of the fairing.
There are a few ways to make this fairing. One you could buy it from one of the many Cub parts suppliers. Or you could just go to the hardware store for a roll of "flashing" and bend up your own. You could also use two stiffer pieces of .020" 2024-T3, flush riveting (from the bottom up) them together at the trailing edge. Both methods are screwed onto the wing with small sheet metal screws. Or you could do it as I did with balsa wood glued to the cove area of the wing and sanded to shape using the flap as a sanding block. Then covering the whole section with fabric.

When this is done you will have about a 1/2" gap above the flaps when they are down. This will allow the higher pressure air from under the wing to flow up through the gap, being accelerated in the narrow slot and down over the upper surface of the flap improving the boundary layer flow. Just like the slats which are popular on the leading edges of some Cubs.

This will remove most, if not all of your elevator buffeting. And most importantly will improve lift at low speeds as well as lowering the stall speed.

Also, your lower surface of the wing ahead of the flap where that current seal is attached should have a large radius curve rather than what appears to be a 90* corner. Look at a "real" Super Cub. The sharp corner will generate turbulence in the air flowing up through the slot. You should try to make your fairing extend to this edge forming a large radius. This may be difficult in your case since the wing was built with the corner on it. And that corner may be a bit too close to the flap. This squared edge will prevent the flap from being as efficient as it could be. An option would be to make a separate rounded piece just for this lower corner rather than to combine it with the upper fairing. You could try just the upper fairing, then if there is still buffeting work on making a curved piece for the lower edge.

Here is a tool to make adjusting the valves a little easier. https://www.aircraftspruce.com/catalog/topages/valvetool.php?clickkey=1444092

Looks like Breeden's adjusted the flaps. 50 degrees is what a stock Cub has.

Looks like you are getting her fit to your mission.

My wings don't have the S shaped flap cove, but without the upper flap gap there was an abrupt pitch down when I pulled full flaps. When the upper seal was added, the problem went away. I also have 58-59 degrees of full flap.
Cool airplane.

Do you have a longer ratchet or longer arm on the flap handle to get the extra flap extension?

Steve Pierce said:

Do you have a longer ratchet or longer arm on the flap handle to get the extra flap extension?

Click to expand...

It's electric.

Steve Pierce said:

Here is a tool to make adjusting the valves a little easier. https://www.aircraftspruce.com/catalog/topages/valvetool.php?clickkey=1444092

Looks like Breeden's adjusted the flaps. 50 degrees is what a stock Cub has.

Looks like you are getting her fit to your mission.

Click to expand...

Ha! yup.
Steve, How does that tool work? I'm assuming its to help hold the screwdriver fixed while locking down the nut, but the side hole isn't being apparent to me. I did it by hand yesterday and #2 was the only one out slightly, meaning .010"-.011" instead of .08"

pb

Farmboy, did you get the pictures which I sent?

I've made the upper flap fairing by rolling a curve on a piece of aluminum then bending part back on itself in a brake. Same shape as Piper did. Fasten lower roll edge in flap cove, flat on top fastened to wing with trailing edge almost touching flap. Extend that fairing over the ailerons allowing for up deflection to seal them some. Loose the lower gap seal there now as noted. The wing rear is similar to a Citabria's configuration with no S shape.

Gary

Farmboy said:

Ha! yup.
Steve, How does that tool work? I'm assuming its to help hold the screwdriver fixed while locking down the nut, but the side hole isn't being apparent to me. I did it by hand yesterday and #2 was the only one out slightly, meaning .010"-.011" instead of .08"

pb

Click to expand...

It has a 3/8" drive.


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Steve Pierce said:

It has a 3/8" drive.
View attachment 42071

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Ah! That’s sweet. Thanks Steve!


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BC12D-4-85 said:

The wing rear is similar to a Citabria's configuration with no S shape.

Gary

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Gary, I believe that the flap hinge pivot is closer to the flap on the Citabria so that the geometry is enough different that there is very little gap when the flaps are down. This would make that corner shape less influential on the flow.

skywagon8a said:

Gary, I believe that the flap hinge pivot is closer to the flap on the Citabria so that the geometry is enough different that there is very little gap when the flaps are down. This would make that corner shape less influential on the flow.

Click to expand...

Yes that may well be. Don't have one here now to compare but will look at the airport. Regardless it is what it is on this Cub. I'd remove one side of the lower gap seals and go fly. Pull on flaps and see if it rolls away from the gapless wing as a test for any improvement gained.

It would do that when I removed the lower seals on my Citabria. Plus I added an outboard +1" endplate to the flaps. That can be done inboard as well to make them effectively longer. But for me by then I had Crosswinds' STOL kit that extended the flaps with a metal extension into the fuselage. Sealing or flowing the flaps and ailerons helps.

Taylorcraft went from a similar sharp edged aileron cove Pre-WWII to a lower curved surface after. Someone must have thought it was beneficial. They increased the height of the dorsal fin too, I guess in combination to reduce adverse aileron yaw reported by NACA.

Gary