Alternative to glow fuel

On 28 Oct 2006 16:56:24 -0700, snipped-for-privacy@digiverse.net wrote in :

The envelope that will work is quite large.

I'm designing and building a utility plane. Sort of a fat stik. 6" x 6" more or less from the firewall to the trailing edge. ~90" wing. Monstrously heavy l.g. and big wheels. I'm hoping that it will fly on 1.20 sizes on up. It's a replacement for a Road Runner that we broke a couple of years ago.

Look at the design of planes that you like to fly. Scale up the dimensions to your powerplant. See how it works. Then make adjustments and see what difference that makes.

Marty

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I never tried to fly a plane with a tank of ethanol based fuel. But I have squirted some ethanol into the carb and flipped the prop. It fired and ran until the prime went away. This was only with the battery connected. I ought to try it again some time.

By the way, ethanol is sold in hardware stores in the USA under the name "denatured alcohol". It has small amounts of something poisonous in it, most likely methanol, to make it exempt from liquor tax.

I wouldn't worry about washout. On a slow, lightweight plane of that size it just isn't necessary. And if I were you I would probably build one set of wings, and then build a longer set if you want it later. By the way, what are you going to cover the plane with? Can you get covering materials in the Azores?

I built a plane a few years ago of about 7 foot wingspan with a 14 inch chord. It had an airfoil that was like you see on a lot of old Ace designs, where the bottom is flat to the spar and then curves up to the leading edge. The fuselage was about 6 feet long and as wide as two soda cans end to end. I designed it with a huge compartment under the wings for dropping various objects, such as the aforementioned soda cans as well as several rolls of toilet paper at once. The design could be very easily adapted for carrying cameras and such. It flew authoritatively with an older Saito 120. If you're interested I could send you a drawing of it. I designed it to be very easy to build and configure.

(I am in GB at the moment) No, but I can carry that kind of stuff in a suitcase or have it sent, it's fuel and paints that take a long time by ship.

Yes, I found that there is no reason not to use flat bottomed wings unless you have a special purpose (scale or aerobatics). I also cut my foam wings with the last 1-1/2" flat near the trailing edge flat so the sag in the wire doesn't affect the shape. Not decided wether to use foam though, It will probably be built up.

I get the picture, thanks. I'm half toying with the idea of a pusher. The twin booms could be made from the bottom sections of telescopic fishing poles. A 4metre fishing pole only costs 7 euros there ($8.70 ?) and has 4 sections. I would have plenty of fibreglass tube left for other models, booms and spars. The point of having it a pusher would be that there is an unobstructed view at the front and the expensive props would be protected. The drawback is that the CofG would be a pain to correct, it's hard to get hold of large pusher props and I prefer taildraggers, so I'll probably just build a normal plane. I'm concerned about the noise as well, the Azores are really quiet and peaceful. If we film wales and dolphins they might get worried too. I would like to add some kind of exhaust expansion chamber in the fuselage to quieten things down a bit and mounting the engine on rubber bushes. Any other suggestions on silencing?

Good excuse to build a big (electric?) floatplane as well though!

On 29 Oct 2006 01:02:42 -0800, snipped-for-privacy@digiverse.net wrote in :

Use a tuned pipe.

You don't have to tune it. It cuts the sound way down and (as a general rule) won't hurt the engine's performance.

Marty

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I am a control line flyer that has done some racing in events where we are limited by tank size. We did try using "everclear" (pure distilled grain alcohol with no water left in it) as fuel to see if we could extend the run and get a few more laps before refuelling. It ran but actually got poorer mileage in our setup (mostly fox 15 engines). It may be worth a try. Bob Furr

"Everclear or pure distilled grain alcohol" will always have water in it. Pleas see wikipedia for a discussion about azeotropic mixtures at

Thanks, it might be an option. When I'm there I will have to investigate further.

I used methhanol from Esso oil at the local airport, plus turbin engine oil by MOBIL...meth. is used to mix ADI for large aircraft....it worked for 2 1/2 years

I'll have to talk to some airport people there.

wrote

You know, you might be surprised at what you can get. Ether used to be available through drug stores, with a prescription.

Alcohol that is probably suitable for mixing your own glow fuel is probably available at marinas, since some boat stoves use alcohol as fuel. It might not be a bad idea to call over there, and find out what _is_ available, before you go, so you can make plans to take what you need.

wrote

First, I'll bet they ship in plastic drums. If not, I'll bet you could specify plastic.

Second, specify a high amount of castor oil, at least 50% of the volume of oil. That would keep rust down in a steel drum; then who cares what it looks like on the outside, and would do the engines a considerable amount of good in a marine environment.

Doubtful that the denatured alcohol is high enough proof. You have to do some real trick distilling and chemical games to get it up to near pure alcohol.

wrote

The exhaust noise is the easiest to quiet. The next big noisemaker is the prop.

You need to homebrew a prop speed reduction unit. I have plans on that line, also. I think some cogged belts and sprockets off of a small table saw, or off of a vacuum cleaner carpet beater brush would work nicely. Add some small ball bearings and a shaft, and you suddenly can pull a big slow plane even better, than using a high revving engine and prop. Sounds like what you need for a camera plane.

I thought about reduction gearing to reduce noise, but it makes things more complicated, heavier and a tad more unreliable, though it should reduce prop noise and thrust considerably. I also thought about a flywheel, or rather not removing weight from an existing one. I haven't got the engine yet, it's in the post, but I think it's worth listening to it without modification and after. What about the pros and cons of a 3 bladed prop?

Denatured alcohol is, depending on country of origin, 90% ethanol with 10% methanol (or other nasty stuff) to reduce drinking pleasure.

I'm pretty sure they get just about all of the water out of it.

I also bought nearly anhydrous isopropyl alcohol at the drugstore once for thinning epoxy. That might burn in an engine, and you're more likely to be able to get it on a remote island with 15,000 residents.

I've converted several of the 18 and 25 cc Featherlite leaf blower engines and they work wonderfully.Vibration is not bad but yuo can soft mount the engine and get it even lower. I've had nothing but good results with the Featherlite engines and they are dirt cheap.

snipped-for-privacy@digiverse.net wrote:

They are not available in europe.