stunthanger.com

Engine basics => Engine set up tips => Topic started by: Steve Thornton on December 01, 2011, 11:55:13 AM

Title: moving the motor aft
Post by: Steve Thornton on December 01, 2011, 11:55:13 AM

I'm still lacking in building skills and I have drilled the holes for my OS 35 S too far forward by about 1/4 inch on my Oriental ARF.  Advice, help, or ideas? Left alone, will it be too nose heavy? I don't need a really high performance plane yet, as I am still learning the basics-loops, inverted flying, etc.
Thanks
Steve Thornton

Title: Re: moving the motor aft
Post by: Tim Wescott on December 01, 2011, 12:39:56 PM

If it's straight and it fits, then it should fly OK.  It'll just look a bit ugly.

1/4" of motor offset isn't going to move your center of gravity by much at all -- if you need tail weight without moving the motor, you'll need tail weight with the motor moved.

Does that model have wood motor mounts?  If you can get in there to drill new mounting holes, 1/4" spacing between the "right" holes and the "wrong" ones isn't too bad.

Title: Re: moving the motor aft
Post by: Balsa Butcher on December 01, 2011, 12:44:41 PM

Left alone it will not be too nose heavy. If you are concerned about the looks (you shouldn't be) add a balsa extension to the fuselage or use a Du-Bro plastic spinner. Their backplates extend a bit behind the engine thrust washer which will make up some of the gap.  8)

Title: Re: moving the motor aft
Post by: Bill Little on December 04, 2011, 03:42:47 PM

Hi Steve,

Both suggestions will work.  Drill new holes or use a Dubro or Goldberg spinner.  ;D

I'd drill new holes if I could.  The Oriental can easily be nose heavy.
 
Big Bear

Title: Re: moving the motor aft
Post by: Steve Thornton on December 31, 2011, 04:26:48 PM

Thanks for the info and advice.  I drilled new holes and sandwiched the engine and bottom of the mounts with 1/16" aluminum strips. I will test fly at the Dallas New Year gathering.  Thank you for all your help
Happy New Year and good flying,
Steve

Title: Re: moving the motor aft
Post by: Rafael Gonzalez on December 31, 2011, 06:17:01 PM

Quote from: Proprpop on December 31, 2011, 04:26:48 PM

Thanks for the info and advice.  I drilled new holes and sandwiched the engine and bottom of the mounts with 1/16" aluminum strips. I will test fly at the Dallas New Year gathering.  Thank you for all your help
Happy New Year and good flying,
Steve

Must be nice to fly on New Year...
 HB~> HB~> HB~> HB~> HB~>

Title: Re: moving the motor aft
Post by: Robert Zambelli on January 06, 2012, 07:04:01 PM

Steve: When I built the prototype Oriental ARF, I used a Fox 35, tongue muffler, plastic spinner and wood prop. It was still noseheavy - I had to add nearly an ounce of tailweight.
Fill the holes with hardwood dowels and JB weld, then drill new holes. Get the engine as far back as possible.

Bob Z.

Title: Re: moving the motor aft
Post by: Steve Thornton on January 12, 2012, 12:25:19 AM

Thanks for all the input.  After epoxying dowels in the existing holes, I used 1/16" alum pads and it seems like it will be just fine.  I asked Tom Neibuhr to look at it and he agreed that it will.  On New Years eve, after getting the canopy installed and the flaps sealed,  I was "exercising" the controls and they jammed solid. Something around the bell crank.  No New Year flying for me.  No more ARF's......ever. Can hardly wait to fly my Twister and build a profile Oriental.
Thanks again
Steve