invaderbissell

Hello!
I just got a small box of RC airplane parts at a garage sale... All for 5 dollars! yay! The best thing in the box was a K&B 61 engine with an 11 inch prop. There was also a 2 channel controler, but from what I've read 4 or 6 channel is needed for an airplane. A bunch of other stuff, but of no consequence as of yet.

I've always wanted to build an RC plane, just never had something to start with. Now I do an that is what brings me here.

I want to design my own airplane, and have already come up with some plans, thought not in complete detail. I would also like to build it out of Balsa.

So my questions...

First, is it a bad Idea to design it myself?

Second, what type of glue should I use? I've read that SIG-bond is used alot, and I've used some other glues in balsa construction before. I've also heard that regular wood glue can become too brittle.

Third, what size of airplane can I have with that K&B 61 engine? I've seen some with as much as an 80 inch wingspan.

That's all for now, any pointers would be gladly accepted.

Thanks,
Bissell

flyinrog

My Feedback: (1)

Just my opinion but you'd probably be wasting your time trying to design a plane,,it would have to be trainer like for a 1st plane..and you would spend more on balsa, covering, hardware, and tools than you would if you bought an ARF trainer..I think Raidentech has theirs on sale for $40... jmho....Rog

dbotkin

There's nothing at all wrong with designing your own airplane, assuming you know what you're doing. If you don't know a fair amount about aerodynamics, aircraft design, model design, etc you're in for a long, expensive and frustrating education.

I personally don't really like the current crop of ARF and RTF planes. I flew RC with my father for many years, mostly with planes he designed and we built from scratch, starting with a 6' span sailplane and moving on from there. We built a few kits as well. There were very few ARF planes back then, and certainly none we ever flew.

As a middle ground, there are what look like some excellent trainer kits on the market. The Great Planes PT-40 (and PT-60), the Sturdy Bird, several others I found look good. The Sig Kadet line kits have a very long and illustrious history. If you're just starting out and don't want to just plonk down your credit card and drive to the field, I would suggest building one of these kits and moving on from there. You can start by modifying your trainer -- once you learn to fly it -- or other kit planes to see what different kinds of changes will do to the flight characteristics. You'll probably have numerous opportunities to do modifications when rebuilding parts of the plane that were !QUOT!re-kitted!QUOT! on landing, anyway. Once you learn more about what it takes to design and build a successful airplane from scratch, go for it.

I'd also suggest something in the .25 to .40 range to start with; .60 powered ships tend to hit a little harder when you make that inevitable miscalculation on approach. But that's me. And don't think I'm down on people who do plonk down a credit card and buy an RTF or ARF plane and start flying. It's not for me, but different strokes for different folks, as they say. I think people are missing a huge part of the enjoyment of flying if they never fly what they built with their own hands, but I also understand that some people just lack the patience, skill, space or time to build.

As for glues... we used to use Sig-ment or Ambroid, but now it seems most people have gone to CA (cyanoacrylate, or Super Glue) for most things and epoxy for the rest. Nothing wrong with either approach, in my opinion. I wouldn't go with Elmer's, but there are some aliphatic wood glues out there like Titebond that I seem to recall we also used with very good results. Any of the glues will last for years, probably far longer than you will be flying the airplane.

Dr1Driver

First, is it a bad Idea to design it myself?

That would depend on your level of experience with aerodynamics and methods of construction. In general, I would recommend that a beginner's first kit be a factory-designed trainer rather than a scratch-built design. The factory kit will have complete plans, wood, hardware and a set of building instructions. These kits will not include radio, engine or covering. Also, you may have to buy additional items, such as wheels and fuel tank.

Second, what type of glue should I use?

My glue of choice is CA. Use thin CA on balsa-to-balsa and thick CA on ply-to-ply. Thin or thick CA can be used on balsa-to-ply.

Third, what size of airplane can I have with that K&B 61 engine? I've seen some with as much as an 80 inch wingspan.

That depends, in general, on what type of plane you're building. A hot sport model may be as small as 60" while a slow and gentle powered glider may be upwards of 100". Weights may vary from 5 to 10 pounds.

Dr.1

flyinrog

My Feedback: (1)

Inv..if you want to get in the air flying then I would still go with ARF,if you need a durable plane check out the SPAD forum,,generally they are tough and heavy so they fly kinda fast,,I have built many kits and scratched a few planes from plans,,if however you are wanting to design a plane...you have a lot of reading yet to do...My last 2 "designs" didnt fly...but they are small .049 planes ..thats what I fly mostly....Rog

invaderbissell

Thanks all for the input.

I'm in no hurry to get into the air. I just need something to take up my spare time <twiddles thumbs>. I've been reading on airplane design for the past several months, but I am by no means an expert... I have done a fair amount of model design, never an airplane though. Before I actually take my future design up I'll prolly get an ARF or something cheap to learn on.

Thanks, I'm sure I'll have more questions for ya'll.

Bissell

piper_chuck

My Feedback: (12)

You're going to get many different opinions on this question. I think trying to design and build your own plane might be a bit of a stretch if you've never build or flown R/C planes before. The "best" way to proceed is entirely up to you.

The purists will advocate tell you that anyone who doesn't go through the right of passage of building their first plane, usually from a kit, is somehow less of a modeler, impatient, searching for instand gratification, etc. If the idea of building a kit appeals to you it's a great idea. One can learn lots about building by starting with a trainer kit. However, the negative labels some of the purists put on those who don't choose to build, are just plain hogwash.

However, many people are more interested in flying than building. The modern ARF has completely eliminated the right of passage that those of us who learned a while ago had to go through before we could fly. People now have a choice and that's a big improvement.

Some want to build their own plane to save money. While it's true that someone who already has the tools, and perhaps extra parts, can build planes for less than a kit or an ARF would cost, but for someone who has no tools or accumulated spare parts, an ARF is one of the least expensive ways to go.

I'd say if you want to design and build your own planes that it would be good to begin with a kit. This will guide you through not only the building, but also engine and radio installation. Once you've got one plane under your belt, you will be in a much better position to put your designs into practice.

And finally, the engine. Before you decide whether or not to use the K&B that you bought, you should try bench running it. If you can get it to run well, it would be worth using. However, if it's not going to run well, you might as well put it away for a while and get something reliable. A beginner needs an engine they can trust. Something that's not working right will significantly slow the learning process. If you've never run an R/C plane engine before, it would be best to find some local help.

If the engine seems like it will be ok, just look for a .60 size kit or ARF. I like the Tower Hobbies ARFs, the price is right and people have good luck with them. For kits, Sig is a great company. Another kit that's worth looking at for a .60 engine is the Senior Telemaster. It's big, flies slow, and will give you lots of experience with building.