towing a glider up

[dancer]

Sorry if I am in the wrong forum with this, but I could not find one to exactly fit my situation.
I want to tow a glider up to altitude and then cut it loose. I live in a flat area and this is the only way I can get it up. Don?t want to fool with bungee cords. This glider is probably not what you are used to, it just a $21 ARF, but will have RC rudder/elevator.

I plan to attach the tow string to the tug plane (here again a $29 ARF) using a stiff piece of music wire firmly attached to the aluminum boom fuse at the exact CG and coming up through the wing material and protruding up about 3 inches long with a wheel collar at the top to prevent the string from slipping off the wire.

What I would like to ask your help on is two things.

Where should I attach the tow string to the glider? I know it should be at the bottom of the gllder, but whereabouts along the length of the fuse? I hope to locate it so that the glider (while being towed) would be in an attitude to create lift and help the tow plane to climb.

The other thing is I cannot mentally design a servo release system. The release servo will be on the glider, but if I could see a drawing or a picture of a release design it would help me out.

The glider will weigh about 8 ounces, auw, and the tug plane weighs about 20 ounces. I plan to hand launch the tug and have a friend

thanks

[Ollie]

Using a tow plane is OK with ailerons, rudder and elevator but not OK for only rudder and elevator. This because the tugging of the line causes the yaw and turn only by rudder.

For with no aileron plane, use piggy-back launch.
http://www.nyblimp.com/projects/pbcarry.htm

[aeajr]

What I would like to ask your help on is two things.

Where should I attach the tow string to the glider? I know it should be at the bottom of the gllder, but whereabouts along the length of the fuse? I hope to locate it so that the glider (while being towed) would be in an attitude to create lift and help the tow plane to climb.


First, is there a reason you have not told us the name of the tug plane or the glider. If possible, provide links to sites where we can see what you are using. That would help. the price of hte planes doesn't matter or help.

The towed glider would normally have the release in the nose area so that it tends to keep the plane straight behind the tug.

YOu would find a LOT about towing gliders in the Scale Sailplane forum as that is a common way to launch them.

Frankly a hi-start is a VERY EASY way to launch a glider, but if you want to tow it up, enjoy!

[aeajr]

Aerotowing
http://www.scalesoaring.net/tow.html

Sailplane Launching Systems
http://www.rcezine.com/cms/article.php?cat=&id=55

How to use a Hi-Start
http://www.rcezine.com/cms/article.php?cat=&id=52

[Steve Boone]

A simple tow release is a piece of square wood with two holes in it. One through the center up/down right throught the bottom of the fuse and a small one front/back with a small wire through it hooked to a servo. Use fishing line and make a loop at one end. Put the loop in the hole and activte the servo so it goes through the loop. When you're ready to disengage cut the throttle on the tow plane momentarily and hit the release. Works great and is simple to do. You can tow a r/e plane but you you need to make very large turns or preferably just go in a straight line before release. I tow my Spirit up this way behind a trainer with a .46FX on it. I just lay the glider on the ground and within a few feet it's airborne. You will get yanked around a bit on turns but if you're a decent pilot it can be done. That said ailerons make things MUCH easier.

[tmattusa]

You would be better off in using a piggy back system. This is a platform which is mounted on top of an airplane and carried up to altitude. There are several manufactures available. In my experience in trying to tow up smaller gliders, they can not take the speeds in which powered aircraft fly and they begin to lose control while on tow.