building without balsa

Is there any interest in building without using balsa? No high tech. Use foam, poplar, and clear Polycrylic. Planes can be built very inexpensively.

I would be interested in some details. I have to order all of my balsa.

I call this "alternate material construction". It's one of my favorite subjects. The only planes I have actually done this way weigh a ton.

Bick Brennen builds his wings for his take apart Barnstormer out of i/16" basewood. They fly good but bulding the whole airplane with this wood would probably be heavy.

When I was in 8th grade I made an exact copy of my Swordsman 18 from the thin boards from a wooden orange crate. The .049 engine took the airplane around and around and around I finally got it to lift off after about 6 times around the circle. I never was able to get the airplane higher than about 3 ft from the ground.

A fellow named Chuck Felton builds Sport Scale controliners using corrugated cardboard. Not practical for Stunt, of course --- unless you don't care about appearance points --- but they do fly rather well. You may have seen some of his designs published in the modeling mag's.

Mike Keville

We have some guys who fly RC Gutterpipe planes with Chloroplast wings. They fly very well. Maybe could be adapted to CL?

Mike


"The task ahead of you, is never as great as the power behind you."

A couple of guys up in the NY, NJ area have been doing just that using carbon fiber. Just how successful those planes are, I have no idea [photo not recovered: sipcof.gif]

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>A couple of guys up in the NY, NJ area have been doing just
>that using carbon fiber. Just how successful those planes
>are, I have no idea [photo not recovered: sipcof.gif]

Do you mean people like Windy Urtnowski?

Mike:
Coroplast or similar material was used in combat over 20 years ago, before the RC guys started using it.

The old memory just kicked in. Coffee helps. During the big one WW2, most model kits were void of all balsa except for one small block. In 1950, my Dad was cleaning out his drug store and going to a sporting goods store. In the process he found three old WW2 era Megow kits on a back shelf. They had cardboard (not corrugated, but card stock type carboard) printed in a purple ink for the formers. The only balsa was small block used for the nose block and the stringers were all ripped spruce. They had about a 20 inch wingspan and of course were rubber powered. I used the motors from my AJ Hornets to power it. Didn't fly for ***&&.

I got real interested in cheaper materials when I went through about 6 airplanes trying to learn the pattern. I built two full fusalage Twisters using home depot foam for wing cores and cardboard fusalage, stab and rudder. The only wood in the front end was pine motor mounts and two 1/4 inch ply bulkhead that acted as landing gear mounts and supported the pine motor mounts. They flew pretty well actually. Lost both learning outside squares. Not the planes fault. In an effort to build as cheaply as possible I was able to build the second one for around $20.00 using spare parts from my other crashes wherever possible. It is possible to build inexpensively but they sure won't win any appearance contests!

Almost all of Ron Pavloer's "BiSlobs" have a cardboard fuselage. Yes, although I wrote the article for Flying Models, the designer is Ron Pavloer. I always want to make sure the Ron gets the credit!

Perhaps you have heard of "Aero Ply Research Co."? This was a little business my partner and I started in the mid-70s. We marketed a 60-size R/C pattern model (a shameless copy of Phil Kraft's Kwick-Fly). Anyway is was made from Monsanto "Fome-Cor", a 1/8" thick polystyrene board faced with heavy paper on both sides. The model, called "Square-Foil" had a diamond airfoil and almost completely Fome-Cor, with a few scraps of ply and spruce.

It was a grand idea, but if suffered from the inability to repair after even a mild crash. The Fome-Cor lost its strength if dented or crunched following a flight mishap.

We sold a couple dozen kits, but my partner lost interest, and I didn't enjoy making kits by myself.

So I kept the company name and logo and eventually wandered into the business of making spark transistorized ignition units. That operation was pretty successful, with total sales of $50,000 over a period of 27 years. I think I saturated the market, so in 2007, I sold my final ignition unit, and concentrated on other things.

Actually, I still build some transistor circuit boards for spark ignition, but I wholesale them to Larry Davidson. Now, I don't get phone calls in the middle of the night from people wanting me to solve their spark ignition problems! What a relief!

Sometimes, those late night phone calls were fun, as from a guy in Australia who spent 15 minutes teaching me how to say "G-Day" in genuine Aussie.

Floyd Carter in OR

A simple example: Corrugated plastic (think political campaign signs--soon to be plentiful).

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MM - you have way too much time on your hands! LOL (kidding)

I can't think of a better way to recycle a "Clinton" sign other than lining my Cat's litter box.

p.s.- Duct tape your leading edges for better performance. Looks great

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I went to an R/C combat contest over the weekend, of the 15 entrants all but two were made from coroplast, the others foam and coroplast.

Very tough airplanes, but unless one was looking for similarity to a Ford tri-motor..............


don Burke
Menifee, CA
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways - body thoroughly used up, totally worn out and screaming, WOO HOO, What a Ride!

One place balsa is going is into blades for wind generators. One could picture a single blade taking a container or two of balsa. Wind power is growing exponentially, and the demand for balsa is growing at the same pace. Now, whether increased demand for balsa dries up balsa for the rest of us, or stimulates more production, perhaps making more available for the rest of us, is the question.

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I flew the Grin Reaper, at real kick in the pants. If you can stay standing.


Paul Taylor

~I wish I knew everything you have forgotten about C/L.

Check out my Blog@
http://rootbeard.rcuniverse.com
A link to a slide show of a fun day: http://www.youtube.com/watch?v=V-_sR0ZydSQ

>A simple example: Corrugated plastic (think political
>campaign signs--soon to be plentiful).
>

The first time an "Edwards for President" sign has been put to positive use!

Brett

>>A simple example: Corrugated plastic (think political
>>campaign signs--soon to be plentiful).
>>
>
> The first time an "Edwards for President" sign
>has been put to positive use!
>
> Brett

They stuck it in my yard without my permission...so I removed it and made a plane with it.

>Is there any interest in building without using balsa? No
>high tech. Use foam, poplar, and clear Polycrylic. Planes can
>be built very inexpensively.

I seem to remember mention some time ago that some former Eastern Block flyers developed methods to use materials other than balsa with good success. I don't recall the materials or techniques.

Perhaps those closer associated with eastern European stunt flyers can shed some more light on the materials and methods used.

V/r

Bob

I'll have to pick up some of the political signs in the area. Make me a few .049 planes inexpensive. I had the plans for one of those models and hope I can find it in all the mess in my garage.

According to a TV program on the History channel, wind turbine blades are made from fiberglass molds, like boat hulls. I haven't heard about any balsa used in their manufacture. The turbine blades are HUGE! I can't imagine balsa having the strength required, unless used as a filler. In that case, the balsa really doesn't contribute to the strength. So why use it?

Floyd in OR

Hi.

Also boat hulls that come from fiberglass molds quite often contain balsa. Balsa is widely used as core material in sandwich composite structures. Other possible core materials are differend hard plastic foams (Rohacell for example) or paper and metal honeycombs.
When used as core material balsa does not work as it does in our toys, it's main work is to take shear and compression loads between the two skins made from fibre composites. For this reason end-grain balsa sheet is used, wood grains are 90 degrees to the skins. End grain balsa sheet has superior compression strengh/weight ratio when compared with most of the other core materials.

Lauri M

When I worked at Boeing in the early nineties, I found some 4X8 sheets of balsa near the dumpster one day, outside a shop that was closing down. It was obviously meant for the trash truck, and I was elated to find such a great treasure!

Closer examination revealed that the grain was through the 3/4" thickness of the sheet, rather than from edge to edge! I thought to myself, what fool would cut balsa cross grain like that?

A little research soon answered my question. The users were laminating it between sheets of aircraft aluminum, to use as structural members.

Bill

Looks like you have enough webbing and gussets to last several lifetimes!

George

Several months ago I built a Williamson Flying Flounder. It has 4 rather large ribs, the plans call for 1/8 balsa. I didnt want to use good wood so I decided to substitute white foam board. I only found one thickness, 3/16" (Walmart & Office Depot). Put it on scale and it works out to about 7.5#/ft^3. Not too bad. It is easy to make accurate cuts with #11 knife by scoring the paper layer on first pass and then making 2nd cut all the way through. In the model I used it for ribs and diagonal braces. It is appropiate for any flat components, but does not carve well like balsa because of the paper surface layers. The edges do sand OK. I got some from 2 different sources, one had white paper on both sides, the other had one side white and the other side red. The Elmers brand from Walmart had a light gray grid printer on one side which makes layout easy. I also used the foam board to make a set of male/female molding forms to mold a the leading edge sheeting, and it worked real well. Using this method instead of wrapping with ace bandage allowed the sheeting to dry and be taken out of mold in about 6 hours instead of the usual 24.

Allan Perret

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Alan-

'really nice. I have had a similar application/configuration in mind, and your techniques are perfect for it. I have some of that stuff on hand. I hadn't expected the average density to work out so well. Great pictures too. Thanks!

SK

What did you glue it with, Allan? And how does it fly?

Same glue you would use on balsa. I used both Elmer's Glue All and Titebond wood glue.
Flys like a maniac. Glides like a brick. With full up control it stalls and mushes thru a loop in about a 8 foot diameter. If you keep it in a 2nd loop after its bleed off most of the airspeed it almost pivots on the prop. Would definitely cuts its own streamer as advertised. But I still rather my BiSlob. The Flounder gets into some wild yawing gyrations when I try hover it, the BiSlob is stable and happy in a hover..
Allan Perret

I used a hot glue gun to put together the two molds. Took about 2 hours to layout and cut the foam pieces and the 2 mdf bases. Using hot glue was able to assemble the 2 molds in about 15 minutes.

Allan Perret

Wonder what would happen if a guy extended the tail and nose a little? Maybe booms for the tail? Or a profile tail end with a rudder that would have more leverage? Guess I could build a Flounder wing and hang a tail on it and answer my own question, but maybe someone already tried this. Any advice or comments?

Hi Guys,

Chuck Felton, here. You hit on my favorite subject, cardboard planes. I just wanted to show you that corrugated cardboard can produce good looking stand-off scale appearance as well as being easy to work with and inexpensive. The first photo is a WW2 Douglas Destroyer naval fighter. It has a wingspan of 65", powered by a 60 engine, weighs 7 pounds fueled with a wing loading of 20 oz/sq ft. The second photo is a Junkers 33 transport with a 72" wingspan. They make great sport flying models.

Coroplast has many of the same advantages as cardboard. But I think cardboard has two big advantages. It's easy to cut and it can be scored and folded to produce realisticly rounded and curved wing and fuselage sections. To see how these models are built, go to my website at http://home.earthlink.net/~charlesfelton and let me know what you think.
Regards, Chuck



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