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Building Tips and technical articles. => Building techniques => Topic started by: Bob Disharoon on March 11, 2007, 06:36:03 PM

Title: RUDDER OFFSET
Post by: Bob Disharoon on March 11, 2007, 06:36:03 PM

Was reading another forum..the guy had a 52 inch wing on his ship and didnt think he had enough line tention..said it didnt feel tight enough...ok..too many variables allready....he is a newbie like me..anyhoo, these guys launch into credit card thickness physics, and almost drove the fellow out of his mind...I build simple sport flyers..Buster,ringmasters..you get the picture..follow the plans..crank in 1/8 to 3/8 rudder offset and a washer or two behind the engine mount....now..bear in mind I havent built anything for 30 years, but Im still building the same way I did then and never had a problem..Now..theve got me scared, because I havent gotten anything airborne yet..but 2 days away for my first flight..Fox 35s on  all ships.....I need a few one sentence advice threads as to whether to worry or not..my vote is no......anyone want to chime in one this one?.....one rule..keep it short and umcomplicated!..thanx in advace, BOB HB~> S?P

Title: Re: RUDDER OFFSET
Post by: Leester on March 11, 2007, 06:44:19 PM

Don't worry.

Title: Re: RUDDER OFFSET
Post by: Bill Little on March 11, 2007, 06:55:58 PM

Piece of cake.

Title: Re: RUDDER OFFSET
Post by: bill marvel on March 11, 2007, 08:50:14 PM

Bob
There are lots of new ways to do things.  But, tthe old ways will work at least as well as they did for you years ago.  As you get some recent time under your belt, you may wish to try a few new things, preferably one at a time!!!

Take it from an old timer.  You will be just fine!!!!  Have fun, guy, and keep us informed of your progress.

regards,
bill marvel

Title: Tip weight
Post by: Paul Smith on March 11, 2007, 09:06:52 PM

Don't sweat the engine & rudder offset.  A little dab will do you.

TIP WEIGHT is where the action is.  If you have enough, you can survive the first flight.

Pick up the plane by the crankshaft & rudder.  Or hang it upside down by the crankshaft & tail skid. 
If the outboard wing definately goes down, you're OK.

If you wanna be really scientific, set pennies on the inboard wing until you achieve balance, then weigh the pennies.  You can tell people what your net tip weight is.   Something around .75 ouinces is a good answer.

Title: Re: RUDDER OFFSET
Post by: Dick Fowler on March 12, 2007, 05:55:27 AM

On short tail moment stuff like Ringmasters, etc., rudder offset (within reason) is fine. The more modern designs with longer tail moments  will be  more sensitive to rudder offset. I thought Lou Crane summed rudder offset up pretty well when he said that rudder offset is most effective when you don't need it! He also said that small amounts of engine offset can't hurt and this helps when you do need it most,when line tension drops off. Good advice.

Title: Re: RUDDER OFFSET
Post by: Howard Rush on March 12, 2007, 12:53:55 PM

I had a Ringmaster long, long ago with the prescribed rudder offset.  It flew better and had more line tension after the rudder broke off.

Title: Re: RUDDER OFFSET
Post by: Bob Disharoon on March 12, 2007, 04:42:21 PM

AS usual...question answered fast, short, and sweet.....BOB H^^ H^^ H^^

Title: Re: RUDDER OFFSET
Post by: Steve Kientz on March 13, 2007, 05:31:43 AM

  H Rush's comment about his plane's tension being better without rudder offset makes me wonder if the Twister I'm building needs the 1/4" of offset the instructions suggest.Any comments? i plan on using a little engine offset.powerplant will be a TT36 or a GMS 32.
Thanks
Steve

Title: Re: RUDDER OFFSET
Post by: Bill Little on March 13, 2007, 06:35:04 AM

HI Steve,

Split the difference......... use 1/8th".

Bill <><

Title: Re: RUDDER OFFSET
Post by: Steve Kientz on March 13, 2007, 10:45:01 AM

  thanks Bill for the input. Had forgot that this twister will have adj. tip weight so 1/8" at the rudder should be fine.

Steve

Title: Re: RUDDER OFFSET
Post by: Howard Rush on March 13, 2007, 05:38:20 PM

Here is a piece on Twister mods by Capt. Fancher: http://www.aeromaniacs.com/Fancherized/pages/p1_jpg.htm

Title: Re: RUDDER OFFSET
Post by: phil c on March 13, 2007, 07:03:25 PM

make the rudder adjustable.  It is too important an adjustment to glue in place.