Flop

[Chuck in Indiana]

While I'm planning a couse of action on building the center section, I've searched here (maybe not well enough) for pix of how people have done the flop. I'm *assuming* There needs to be a sub spar aft of the rear spar strong enough for a hand hold and to hinge the flop from?
Any pix of that construction? Thanks!

[taildrags]

Chuck; a couple of photos of the setup on my plane are attached. It's just as you describe, with a false spar aft of the centersection aft spar, and mine has numerous openings in it for access to the aileron connecting cable that crosses through the space between the aft spar and the false spar. I fabricated a removable link between the port and starboard ends of the connecting cable and in the past it's proven very handy when removing the wings. A turnbuckle can be used in place of the link that I used but they're more trouble and fuss than my setup, which has clevis pins with very simple cotter pins at each end. I've also included a shot from under the wing, showing how that cavity can also be accessed from below.

Note that since the flop itself is entirely aft of the rear spar, it can be made wider than the centersection on the port side to make it easier for the pilot's head to clear, but mine is just the standard width... same as the centersection.

Oscar Zuniga
Medford, OR
Air Camper NX41CC, A75 power

[Richard Roller]

Essentially the builder of my bird copied the aileron spar setup, including location on the rib and the strap style hinges, with the spar piece being one rib bay wider than the center section on the left side. That is for ease of entering the pilots seat. This setup will lie flat on the top of the wing.

[Richard Roller]

One more thing. Mine doesn't have hand holds, like Oscar shows in his. I grab the top of the cabanes when I get in. I think hand holds would be a good idea.

[Chuck in Indiana]

Sometimes, a picture is worth a thousand words.. Thanks, guys!

[taildrags]

Richard's point about the flop lying flat on top of the wing is not only useful, it's important. The hinge on my flop wasn't properly placed when it was installed and I'm too lazy to mess with it, but in short, it doesn't provide enough swing for the flop to go all the way forward to lie flat on top of the wing. No big deal unless a wind is blowing, and in that case it can flop around and pull the screws that hold the hinge in place out of their attach points, or it can flop backwards. In any case, when you fit up your flop, make sure it lies nice and flat when pivoted forward. I wish mine was, and one of these days I'll refit it correctly before it pulls out the hinge screws out or something...

-Oscar

[Chuck in Indiana]

Will do. Thanks, Oscar.

[KenBickers]

So ...

Everything about everything in airplane design is a compromise. My flop, like Oscar's does not lie flat on top of the wing. And like Oscar, I've had mine blow shut in a strong wind, which has almost always -- okay, always -- been my own fault for starting the engine with the flop in the upright position.

Here's the thing. If I were building mine all over again, I'd still build it the same way. In order to have the flop fold open and lie flat on top of the wing, the nuckles of the piano hinge holding it in place would have to protrude into the slip stream. In order to "hide" the hinge from the strip stream, the nuckles have to be positioned in the down position. Doing that means the flop will open to about 135 degrees, but not 180 degrees.

I'd rather be reminded with a loud, but otherwise harmless bang from time to time about the reason for following checklists than to have that row of nuckles sticking into the wind. Piets are draggy enough without adding yet more drag simply to avoid forgetting to lower the flop.

Here's a pic. One thing I do like is that I have a small glove box in the forward portion of the flop where I keep gloves, rags, and other very light items.

Cheers, Ken

[rightforlineup]

Always interesting how much conversation goes into this subject.
No flop works just fine.

[bob turner]

So I can simply remove the flop and fly safely? That would be way better - or just a circular notch like the Stearman?