Design > Stunt design

Profile Fuselage Width

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Ken Culbertson:
I have found the right profile fuselage width at 3/4" but I can't seem to find where that starts in any of our threads.  Obviously the nose can be thicker.

Ken

Brent Williams:
.750" at the trailing edge is what I have read.

Ken Culbertson:

--- Quote from: Brent Williams on February 04, 2021, 05:15:14 PM ---.750" at the trailing edge is what I have read.

--- End quote ---
If that includes the flaps I am a happy camper.

Ken

Dave_Trible:
There really are no real written rules to define this.  Historically it's been a matter decided more on a local basis.  In most cases over the years in many places here in the midwest it is a max of 3/4" overall except perhaps a small cheek cowl like the Goldberg profile airplanes.  That means a build of 1/2" balsa with 1/8" plywood doublers each side-all the way to the nose.  I know in the last ....years this has grown into aborations of up to 2" in the nose area as long as it tapers back to something like 3/4" behind the wing.  To me (and simply my opinion) that comes close to defeating the spirit of 'profile'.  If I were to hold a profile event I would hold strictly to the 3/4" measurement.  I might give some leeway to a radial mounted engine but would still want to get back to 3/4" by the time we got back to the high point of the airfoil.  PAMPA went through quite a lengthy session attempting to develop uniform rules for 'Profile".  We ended in a stalemate.   Back to local rule.

Dave

Dan McEntee:
 The 3/4" measurement in the rule book is mainly for profile scale at AMA sanctioned events, I do believe. There is no official profile stunt event rules and the argument has been hashed thoroughly. My contention has always been that what constitutes a profile has been dictated by the endless number of kits produced over the last 60 years in that configuration and the limitless number of plans that have been published like wise. Also, what constitutes a profile is the sidewinder engine mount, like these kits and plans have demonstrated. A doubler or cheek addition on the inboard side really isn't problem to me as long as the engine is still a side winder mount. I have a built up model that I inherited hanging in my garage that a fuselage that is thinner than 3/4" at the trailing edge. that can raise the argument bar a little, and then asks the question, where are the control rods? Inside or outside?
   The answer to the question is, just build a normal profile! If you want to make use modern materials and construction techniques, have at it. It can be made plenty stiff to perform well and still look like a 1/2" slab e of balsa.
   Type at you later,
   Dan McEntee

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