Test005

Help me get a glow powered glider.

Are there any folding propellers to glow engines?
Can an electric folding prop be used or is it too weak for the high rpm or what's the deal?

I really want to stay out of electrics but I would like to have a glider/big sailplane.
Nobody flies gliders at our field and I don't want to use hi-start or winch, then the only option seem to be an electric motor, but here's where I want to go with glow engine + a small fuel tank.
The idea is to climb until the fuel runs out, then the prop folds and voila' I have a glider!

Anybody have any tips or input on this matter?

-Are there any folding props to fit on a small glow engine
-What size engine is required for what size glider. (I figure it can be pretty small because I'm not looking for performance or speed, just enough to slowly climb for a minute or two.)


OK, OK I really see the benefits to have an electric motor which can be switched on/off and all this "silent flight" propaganda coming my way
I just don't want to start get involved and learn everything about electric motors, ESC, batteries etc... + It'll cost to much to get all the stuff and a new charger.
I'm also interested to get a quite big glider 2.5M - 3M and then I'd need to get very beefy electrics = expencive!

rcalfred

Do you really need a folding prop? Can there really be that much drag from a prop? I have started a 1/4 scale model of the T61 Falke motor glider (147" span). Uses a .45 to .91 glow engine. The articles I found on the web show the full scale plane with the prop still and horizontal and happily gliding around. My opinion is that, once you get the glider into the altitude where the thermals are, there will be plenty of lift and it will offset what little drag the prop would give. Let's see what others have to say! My personal opinion is that having a folder on a glow engine is asking for trouble, and/or injury, when it flies apart. Regards.

Dsegal

You cannot use an electric folding prop on a piston engine. There are no commercial folding props for piston engines and you don't need them. Set the prop so that it is horizontal when the piston comes up against compression and you are not likely to break the prop on landing. I fly 2-meter gliders with a .10 cubic inch engine. If you are able to handle smaller engines (I cannot) then you might use a .05 to .07 size. Make your radio gear lightweight also. These planes are inexpensive and great fun to fly. Very relaxing- get a chair so that you can keep your eye on it when it is up high.

Test005

Great!
This is the reply I'm looking for...kep'em coming !

What glow engine would you choose to put in this glider for example?:

Scorpio Condor Magic 2.9
Semi Scale Glider/Motor Glider
Wing span 2900mm - Length 1240mm - Wing area 52sq.dm. - Wing loading 29/42 g/sq.dm. Radio required 3/4 channel. If using power model requires a 700 gear motor, speed controller, prop and 3000 mAh powerpack are required.

Dsegal

For those of us who must think in terms of the U.S. Customary System (yes, that is what it is called) I have done a few conversions so that others might join in with suggestions on appropriate engine size. 2900mm = 115 inches wingspan. 52 sq.dm. = 806 sq. inches or 5.6 sq. feet of wing area. My guess is that a .15 cu. in. engine would be OK.

Test005

Thanks DSegal for you effort to convert everything fro metric, perhaps I'll get even more input now when you Americans "can read" the specs?

What about the O.S 15-LA C/L (This is a control line engine, perhaps this sort of throttle-less carburator would suit my project?)
Propped with Master Airscrew (quite durable props) 8X5?

Dsegal

You could use that engine but I do not like the absence of throttle control. I use the throttle servo to shut down the engine when the model has reached the desired altitude. A throttle is also a safety factor allowing you to kill the engine if some unforseen situation occurs. Personally, I would not fly a model lacking a throttle with an engine larger than .06 cu.inches.

Test005

I understand your concern but I fly in a small club away from civilization )
My idea is to make things as simple as possible and even with a throttle carburator I'd use a rubber band or pushrod to keep it WOT.
Running out of fuel will be the method of shutting down when altitude is reached.

My only concern with an engine .15 or bigger is that I'll start to fly the glider too hard and fast and break it.
These airframes are not made for high stress but with a fast engine up front it would be tempting to forget about this "soaring" business and instead yank and bank it at high speed

Test005

Allright, me and a friend will place an order at Tower tonight.
Any last recommendations on which engine, props & peripherials I should get for a future "glow glider" project.
2.5 - 3M wingspan.

JohnBuckner

My Feedback: (1)

That ship sounds as though it is of fairly high performance, I don,t know if it has spoilers or not but even if it does without a throttle you are at risk of a flyaway. If you use a throttless engine no problem just use a small servo on a pinch off. A wire from the servo hooks the fuel fuel feed line and pulls it through a wire loop when activated. This can get you out of trouble. I now use this on a rudder only vintage RC airplane that has already had one flyaway and we use it on the American Q40 class pylon racers that have no throttle.

The stationary prop is not going to be a major drag issue and the .15 others has suggested will be about right for what you want to do. please don,t use an engine that can,t be shut down or eventually you will lose it.


John