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Building Tips and technical articles. => Building techniques => Topic started by: Bill Smith on September 30, 2007, 04:55:03 PM

Title: Sig Mustang
Post by: Bill Smith on September 30, 2007, 04:55:03 PM
I've got a Sig Mustang kit. any advice on building it?
It looks like I could do some stuff to lighten up the wing.
Title: Re: Sig Mustang
Post by: steven yampolsky on September 30, 2007, 07:09:50 PM
1) mold as many parts as you can. Avoide using plastic parts at ALL costs
2) sheet the wings with 1/20 balsa and send them to get cored afterwards
3) carve wingtips out of balsa
4) Get Constrol system from Tom Morris

General idea is to keep the weight down. replace all plastic and keep an eye on balsa kit parts. Replace any wood that's over 8 pounds.

Title: Re: Sig Mustang
Post by: wmiii on September 30, 2007, 08:33:41 PM
  What he said. If you don't mold the parts. then use the best balsa you can find, carve & hollow the blocks.

 Walter
Title: Re: Sig Mustang
Post by: Chris McMillin on September 30, 2007, 09:19:32 PM
What these guys said.

Two more things from Jim Lee, copied by Dan McEntee and Mark Hughes in their very good flying Mustangs;
increase the stab/elevator span 3 inches (draw a new one with the root and tip chord the same, just 1 1/2 inches longer each side and;
increase the tail moment 1 inch.

These changes will carry the mufflers and a little heavier engine very well.

Chris...
Title: Re: Sig Mustang
Post by: Clint Ormosen on September 30, 2007, 10:00:12 PM
Also, redesign the nose section for a crutch and slide in tank.
I streched the tail moment 1" on mine. I decided to not enlarge the stab/elev span because it made the model look stupid.

......and use a 3.5" suspended bellcrank.
Title: Re: Sig Mustang
Post by: phil c on October 01, 2007, 09:53:52 AM
The stock Sig Mustange uses a bellcrank mount glued to the foam, without any structure tying it to the sheeting.  Don't do it.  Use ply pads on top of the sheeting and run the bellcrank on a through shaft(be sure and lock the through shaft in place so it can't work its way out.)  Saw a plane crash a couple months ago when the through shaft bored a hole through a 1/8 in. 5 ply cap and let the bellcrank slip down and lock up.
Title: Re: Sig Mustang
Post by: Bill Smith on October 01, 2007, 06:15:36 PM
Lots of good ideas thank you all.
I'm cleaning my shop out now then I have to spread this out and compare ideas with kit.
Hope I don't screw this up.
Title: Re: Sig Mustang
Post by: Leester on October 01, 2007, 07:00:22 PM
Bill: I think your on the right track to NOT screwing it up by asking here. Any problems or more questions ask first.
Title: Re: Sig Mustang
Post by: Clint Ormosen on October 02, 2007, 12:56:16 AM
Here's my Sig 'Stang getting ready for paint.
Title: Re: Sig Mustang
Post by: Clint Ormosen on October 02, 2007, 12:59:59 AM
The bottom. ;D
Title: Re: Sig Mustang
Post by: Alan Hahn on October 02, 2007, 01:23:21 PM
Bill,
Ask Fred K. at the Treetown meeting tomorrow. His Mustang was derived from Jim Lee's numbers on the Sig Mustang.
I won't be there tomorrow. I am typing this from Geneva----Switzerland, not Illinois  #^ .
Alan
Title: Re: Sig Mustang
Post by: Bill Smith on October 02, 2007, 04:43:26 PM
nice job Clint
any idea what the weight might end up at?

Alan I remember Freds Plane but didn't he do a built up wing??
Title: Re: Sig Mustang
Post by: Clint Ormosen on October 02, 2007, 06:30:37 PM
Right now it's on track to be 43-44 oz. with a Brodak 40 in it. That's if the finish doesn't get too heavy.
Title: Re: Sig Mustang
Post by: Alan Hahn on October 03, 2007, 01:20:45 PM
Yes he did build up the wing. I am not sure how much weight that saved him, but I thought it was nominally the same airfoil as the foam wing. But he'll tell you.
Alan
Title: Re: Sig Mustang
Post by: Mike Spiess on October 08, 2007, 11:21:12 AM
Mike Stotts he built for the catalog photos.
Title: Re: Sig Mustang
Post by: Mark Scarborough on October 08, 2007, 12:53:45 PM
UMM ARENT THOSE PICTURES OF THE CHIPMUNK?
Title: Re: Sig Mustang
Post by: Bill Smith on October 18, 2007, 06:17:23 PM
Sorry for the time lag in responding to all the comments and emails. I want to thank all of you who took the time to respond. I have a good idea of what needs to be done now, and have it all written down. Now all I have to do is find time this winter to do it.
Title: Re: Sig Mustang
Post by: Clint Ormosen on October 18, 2007, 09:19:53 PM
Bill, be sure to post your progress. Building pictures are great.