Laser / Turbo prop build

[forgues research]

	Quote: Originally Posted by 3Dguy
	Schweet. How are you going to deflect the exhaust?

Sorry for the late reply, I will tend to this issue once I am there, but I don't anticipate any problems

Roger

[forgues research]

	Quote: Originally Posted by ozzietx
	I just found this thread. Very interesting. I won't be doing a turboprop anytime soone, but am interested in the wing construction. I am going to be building a 30% Yak 54, and might be interested in using this method for the wings. I noticed there is not much detailing on the leading edge , trailing edge, or hinging construction. Is that because you are still waiting on materials? I do have some questions, that probably will reflect my ignorance. I have not found the extruded foam to be super rigid. It seems like it might be easy to build a wing that is out of alignment. How do you guarantee a straight wing? How do you set up the templates on each end to insure accuracy? Do the wing skins glue well to the foam? Is ther a significant weight savings with this method? I don't want to hijack this thread with questions about the construction. Is there somewhere that might have more info on this method? Thanks, Bryan

Hi Bryan, no problems with your questions...
Actually this is the best way to build the straightest wing possible.

If you go back some pages as I am cutting the airfoil, you will see that the foam is boxed in so nothing moves, then you put the stringers, wng tube, and everything else that has to go in before you sheet this half, once this is done, then you cut the other half with everything in place.

I use carpenter's white glue to glue everything on the foam and yes it is plenty strong.

As for the leading edge and trailing edge and ailerons, I am waiting for the sheeting material which they told me it should be in within a day or two,

As for weight difference, I have not done two identical wings , where one is this method and the other is solid foam, so I can't answer your question, maybe Jack or Scott can jump in with this ..

Also don't use the white foam as this will not be strong enough but you can use the pink or blue foam.

Roger

[airbornrc]

I built identical wings. One was honeycombed white foam cores the other was blue foam ribs like Roger is doing they were very close in weight (2oz lighter for the honey combed wings). These are much quicker and easier to do. Honeycombing the white cores removed 6oz per wing so these would have been 4 oz lighter with out the glue that would have been where the honeycombing was. My wings were 35%.

Mark

[forgues research]

	Quote: Originally Posted by airbornrc
	I built identical wings. One was honeycombed white foam cores the other was blue foam ribs like Roger is doing they were very close in weight (2oz lighter for the honey combed wings). These are much quicker and easier to do. Honeycombing the white cores removed 6oz per wing so these would have been 4 oz lighter with out the glue that would have been where the honeycombing was. My wings were 35%. Mark

So Mark, what you are saying the foam core wing without honeycomb would be heavier then the jig built wing I am doing here.

Thanks for the info

Roger

[ozzietx]

Roger,

I see how it is boxed. I guess the extruded foam is strong enough to not deform while sheeting?
My first big question is, how do you determine where on the foam to put the root,
and tip templates? How do you cut accurate wing socket holes?

I have looked at the pics again, and am feeling kinda stupid. I must be missing something.

I'm sure it will be clearer to me with further construction photos. I'm looking forward
to more. This is very interesting.

Thanks,

Bryan

[jbdesigns]

	Quote: Originally Posted by ozzietx
	Roger, I see how it is boxed. I guess the extruded foam is strong enough to not deform while sheeting? My first big question is, how do you determine where on the foam to put the root, and tip templates? How do you cut accurate wing socket holes? I have looked at the pics again, and am feeling kinda stupid. I must be missing something. I'm sure it will be clearer to me with further construction photos. I'm looking forward to more. This is very interesting. Thanks, Bryan

Hi Bryan,
this jig built method has been used for years but is largely not understood by many modellers. so to help out a little, people like Roger here are trying to help other modellers to understand the construction better. i also did a thread on building this type of wing. Roger won't mind if i point you to the thread since it will help answer some questions you have and we are all interested in teaching.

see this: Jig built foam rib wings--how to.

good luck,
John

[forgues research]

	Quote: Originally Posted by jbdesigns
	Hi Bryan, this jig built method has been used for years but is largely not understood by many modellers. so to help out a little, people like Roger here are trying to help other modellers to understand the construction better. i also did a thread on building this type of wing. Roger won't mind if i point you to the thread since it will help answer some questions you have and we are all interested in teaching. see this: Jig built foam rib wings--how to. good luck, John

John , I sure don't mind, this is what its all about and your thread on this type of wing is great, thanks for sharing.

Roger

[ozzietx]

Gentlemen,

Thank you so much for the link. That really cleared up a lot for me.
Now I think I understand. I may use this method myself.

I look forward to more progress reports when you receive your materials.

BTW, where are you guys purchasing balsa from? I used to get mine from
Lone Star, but the had a fire, and it doesn't look like they will be re-opening
any time soon.

I have not heard any favorable feedback about any other vendors.

[jack strickland]

	Quote: Originally Posted by ozzietx
	Gentlemen, Thank you so much for the link. That really cleared up a lot for me. Now I think I understand. I may use this method myself. I look forward to more progress reports when you receive your materials. BTW, where are you guys purchasing balsa from? I used to get mine from Lone Star, but the had a fire, and it doesn't look like they will be re-opening any time soon. I have not heard any favorable feedback about any other vendors.

Hello, I have had good luck with Balsa USA, if you want they will select for you, weight wise.

[jack strickland]

	Quote: Originally Posted by forgues research
	John , I sure don't mind, this is what its all about and your thread on this type of wing is great, thanks for sharing. Roger

Hi Roger, I have always suggested to scratch builders, that any idea about construction, cement, aerodynamics, etc. can always be improved upon. Not to worry about a little hatch mod, actually a good idea. Remember, the more one builds the same design, the more improvements will happen, one tends to make subtle changes as one builds the same design for a number of years. Your plane is looking great, keep up the excellent work.
Regards
Jack

[jack strickland]

Just a thought here, Have been building the Laser for 28 years now, both 33% and 40%, have never used any heavy epoxy, (not cement anyway), in any of the 14 planes built. Also the main spars must be kept from crippleing, from g loads, with vertical grain balsa between the spars. This is a little more time consuming, but absolutely necessary for a strong spar, one may use shear webs on the rear spar. The 40% wing must be fully sheeted to prevent a possible flutter problem, this info is from experience. Sorry Roger, did not mean to cause any problems.
Regards to everyone
Jack Strickland

[forgues research]

	Quote: Originally Posted by jack strickland
	Just a thought here, Have been building the Laser for 28 years now, both 33% and 40%, have never used any heavy epoxy, (not cement anyway), in any of the 14 planes built. Also the main spars must be kept from crippleing, from g loads, with vertical grain balsa between the spars. This is a little more time consuming, but absolutely necessary for a strong spar, one may use shear webs on the rear spar. The 40% wing must be fully sheeted to prevent a possible flutter problem, this info is from experience. Sorry Roger, did not mean to cause any problems. Regards to everyone Jack Strickland

Thanks Jack,
I appreciate your input, every little bit counts..

Roger