I need help.
I am attempting to build my first plane from scratch. Actually an electric thermal glider. I have the airfoil that I want to use - RG15 - and have done research on how to cut the foam wings. I built and tested the foam cutter – works great. Will use balsa to sheet the wing.
I am going to make the wing 110” from tip to tip.
My problem is the body. I am not sure what length to make the body. I also would like to make the body out of fiberglass but again not sure how to do this. Balsa and plywood is always an option for the body but ideally I would like to make it out of fiberglass.
If you have any ideas on what length/thickness the body should be, or how to make it, please e-mail me at:
[email protected]

I would appreciate any information that one has to offer.
Thank you

Okay, first of all why are you using RG15 for the airfoil? That is a very fast section. How much flying experience do you have? How fast do you want this plane to fly, and how gentle or forgiving do you want it to be? If you're new to flying, you definitely don't want to use RG15. If this is your first glider use an E205 or S3021, if it's your first plane of any sort then use a Clark Y.

What sort of power system will you use - what motor and how many cells?

A 110" wing with the RG15 airfoil is going to be very thin, you'll need more than just foam and balsa or it will fold up pretty easily.

There are plenty of published designs available, you don't need a kit if you can cut your own wood. But if someone else has already done the design work for a similar plane then it makes sense to build that instead, unless you really have a good reason for wanting your own design.

Steve, thanks for the information.
I actually have been flying for many years and have a lot of experience with fast and slow planes. I fly delta wings, giant scale, helicopters and also have a high performance glider that will do 110 m/h in a dive.
I am not worried about the speed of the plane. I just would love to build my own from scratch. I decided on the RG15, I actually have already cut the foam, reinforced it with carbon fiber and also sheeted it. It came out really well. Now I am not quite sure what length or how to actually make the body out of fiberglass. I can always resort to balsa but would prefer fiberglass.
As for the power, well I have a program that will tell me what kind of motor, size prop and how many cells to use. That will come last after the plane is complete and I can weigh it.

kouger:

I have two sailplanes (Graupner) with wingspans of 110" and 118" and both use fuselages 45" in length.
Hope this helps out.

Alvin

Kouger,
I do not believe one word in your prior posts!
Puff

That is a big help, thanks.
One other thing though, what is the size of the tail? Is it a V or standard. I would like a V and have a set that I was going to use from my other glider however I am not sure if they are actually big enough. My other glider is a Falcon with a 78" wing span. It thermals quite well and with the motor on it (Aveox 1015 with a 14.5x9 prop) will climb quite high in 30 seconds.

Now Puff,
Tell me why you think I would lie?? What do I have to gain from it and what exactly don't you believe?????????
Surely you could back up that feable statement you made??????!!!!!!!!
kouger

kouger:

Both of the fuselages are ABS plastic, the vertical tail is an integral part of fuselage. It is a standard cross design. The height of the tail above the fuselage is 8.5"H x 3.5" at the base. With the long wings, the aileron version has a rudder that tapers from 1.5" at the top to 3.5" at the base. The e/r version has a rudder which is even larger. Both horizontal stabilators are full flying type, with 124 sq. inch area.
If I can be of any further help, let me know.

Thanks for the information. I think that I am going to stick with a V tail as my other glider has one and it will make it somewhat easier for me to try and copy the layout/design of it. The dimensions that you supplied are of help nonetheless - thanks
Kouger

Kouger, my first thought is to search out 3 view drawings on the net for other sailplanes and get your inspiration for the fuselage and tail sizes from them.

If in doubt making the fuselage longer and the tail larger by a small fraction will only make it fly better but at perhaps the very slight cost of a small amount of increased drag from the small extra amount of area you build in.

There's nothing like doing some good natured plagarizing.... er make that "research" when designing your first model of a given type. Just be sure to match the tail lengths to the areas. In other words don't steal the short tail length off one model and the small tail area off another. Stay consistent. The safest method is to find as many drawings as you can and average them. Be aware that the aspect ratio of your wing also plays a part. Steal from designs that are close to your wing aspect ratio.



Puffmaru-
That comment was totally uncalled for.

BMatthews,
Thanks for your help, sounds like a good idea. I will have to start doing some more research. I actually have finished the wing, except for covering. The body is in the works and should be done by tomorrow. I made it about 50" but left enough room to cut it shorter if need be. Now I have to find out about the tail and also about mounting the wings. Not quite sure of the angle (incidence) the wings should be. I am going to try and match it with the glider I have already. I will have to post some pictures of the finished product when done.
Thanks again for you help.
kouger

BMatthews,
Thanks for your help, sounds like a good idea. I will have to start doing some more research. I actually have finished the wing, except for covering. The body is in the works and should be done by tomorrow. I made it about 50" but left enough room to cut it shorter if need be. Now I have to find out about the tail and also about mounting the wings. Not quite sure of the angle (incidence) the wings should be. I am going to try and match it with the glider I have already. I will have to post some pictures of the finished product when done.
Thanks again for you help.
kouger

Kouger,
I do apologize for my uncalled for intemperate remark. I should keep all my replies postive, or no comment at all.
Puff

A simple method for making a one-off FG fuse is to carve it out of dense blue foam, sand it smooth, and lay up glass cloth on it as smoothly as possible. When hard, cut a hole somewhere- wing saddle is good, and slowly pour laquer thinner into it. The thinner will dissolve the foam (test first). The fuse will be a little rough, so coat it with lightweight spackling and sand smooth. Coat with sanding sealer, sand and paint it. Don't breathe the fumes!