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General control line discussion => Open Forum => Topic started by: Phil Coopy on March 15, 2009, 11:09:49 AM

Title: Flap Throw?
Post by: Phil Coopy on March 15, 2009, 11:09:49 AM

The flap throw on my new Gee Bee project seems to be sort of minimal.  How much minimum throw should I work for on a stunt plane?  My Vector has a lot more. Pic below shows max throw.

Phil

Title: Re: Flap Throw?
Post by: Bootlegger on March 15, 2009, 12:04:27 PM

        Phil, Looks like the p/rod is in the top hole on horn, try dropping it down to next hole and see what you get..
   Then put the flap/elev rod in top hole ...

Title: Re: Flap Throw?
Post by: Bob Reeves on March 15, 2009, 12:27:20 PM

Rule of thumb is 30 deg.

Title: Re: Flap Throw?
Post by: Serge_Krauss on March 15, 2009, 08:44:24 PM

Phil-

My protractor says you have about 20 degrees of up there.  From the small horn arm, it seems that your bellcrank rotation must be restricted in some way, since the inside bellcrank-arm hole is usually sufficient to give the 30 degrees. You can move to an outer bellcrank arm hole, if you don't have room for it to rotate around 38 degrees (or more). You might also check your down deflection for bias. While, as Bob says, you should probably have 30 degrees available, more than one competitive stunt flyer claims to use less than 20. It really depends a lot on wing loading - how heavy the plane is for its size. One other thing to look out for is that, if you use the upper hole for the flap-elevator linkage, be sure to use a comparable hole spacing on the elevator horn, at least for the first flights.

I posted some bellcrank-flap geometry stuff that was met with underwhelming acceptance on SSW forum recently by couple of my on-line friends here, but you might find it interesting.

SK

Title: Re: Flap Throw?
Post by: Phil Coopy on March 17, 2009, 05:10:56 AM

Thanks guys,

I moved the pushrod down one hole and now I have 30+ degrees of movement in both directions.

Phil