Laser / Turbo prop build

[forgues research]

This morning I got the two fuse sides started.

Also glued the top wing sheeting on the second wing again using the method I used in 1991. Both give the same results , its just a matter of preference.

Roger

[forgues research]

OOPS, here is the fuselage sides,

[stevep]

Looking good Roger, I love lasers

[McFueler]

Well it looks like Walt's dog (Boomer) is not the only famous dog now !!!!

[forgues research]

	Quote: Originally Posted by McFueler
	Well it looks like Walt's dog (Boomer) is not the only famous dog now !!!!

Ya but she don't care, give her food and she is happy, by the way she is a Golden Retreiver which I had shaved in late April

Roger

[jbdesigns]

	Quote: Originally Posted by KEITH RUSH
	How did you cut the holes in the ribs for the tube socket so that it is square in the wing panel? Also instead of using spruce for the wing spars, could you use balsa spars with carbon fiber mat laminated to one side for added strengh? The reason I ask is I am ordering a set of plans today from Jack, and I am thinking of using a 3W-106 and trying to think of ways to keep the weight down. Thanks, Keith

Keith,
on using balsa/carbon for the spars instead of plain spruce. it is important to know that most wing failures occur due to a failure of the spar which is in compression. it most always bukles and then the wing fails. for example, the spar in compression would be the top spar if you are pulling positive g's. balsa and carbon laminates can be good and strong in tension, but unless they are done very well, they are not so great in compression to resist bukling. to be strong at all to resist buckling, they need carbon on both sides of the balsa stick, essentially making the stick into a mini I beam. the carbon strips are the top and bottom of teh beam and the balsa acts as the shear web in between. for all of the work to make this special spar, i just forget that busy work and use good old spruce. while i am confident that if designed properly and used, the carbon balsa spar is a little lighter. but i mean it has to be designed and determined that the spar is sufficient for the job. i don't like going right to the bleeding edge of technology as when you go there, you often get bit. i don't have the time resources to build multiple airframes while i experiement.

i am not trying to scare off anyone trying to substitute composite materials in place of the traditional natural ones. i just want those that go that direction to know there is inherent risks. with the risks, come rewards and possible failures. everyone has different thresholds for risks and that is what really determines how far some will go with their experimentations.

good luck to all who dare to be bold and venture into new territory. i love it all.

John

[forgues research]

	Quote: Originally Posted by jbdesigns
	Keith, on using balsa/carbon for the spars instead of plain spruce. it is important to know that most wing failures occur due to a failure of the spar which is in compression. it most always bukles and then the wing fails. for example, the spar in compression would be the top spar if you are pulling positive g's. balsa and carbon laminates can be good and strong in tension, but unless they are done very well, they are not so great in compression to resist bukling. to be strong at all to resist buckling, they need carbon on both sides of the balsa stick, essentially making the stick into a mini I beam. the carbon strips are the top and bottom of teh beam and the balsa acts as the shear web in between. for all of the work to make this special spar, i just forget that busy work and use good old spruce. while i am confident that if designed properly and used, the carbon balsa spar is a little lighter. but i mean it has to be designed and determined that the spar is sufficient for the job. i don't like going right to the bleeding edge of technology as when you go there, you often get bit. i don't have the time resources to build multiple airframes while i experiement. i am not trying to scare off anyone trying to substitute composite materials in place of the traditional natural ones. i just want those that go that direction to know there is inherent risks. with the risks, come rewards and possible failures. everyone has different thresholds for risks and that is what really determines how far some will go with their experimentations. good luck to all who dare to be bold and venture into new territory. i love it all. John

Good information John, thanks for posting

Roger

[Pittsflyboy]

Interesting work Roger.

[eagle1]

subscribed

[forgues research]

Thanks guys, I will post more pictures later tonight
Roger

[forgues research]

started to box up the fuselage with stick build, not fast as I have stated before, not an ARF....

Roger

[KEITH RUSH]

John,

Thanks for explaining what is going on with the wing spars. Very good detail!!! I'm
totally not in the position to be the experimenting ginea pig. Spruce it is for me.

Thanks,

Keith