shyml

I plan to aerotow the Major Hobbies Mytery ship 118" all wood glider. Since we fly off a concrete runway, a belly wheel is needed for take off and landing. What is the ideal location with respect to CG.
Amer

Tall Paul

Slightly ahead of the c.g... say a 15° degree offset.
Do you have a side view?.. put the c.g. at the wing location, then go 15° forward of a vertical from that.

MTT

My Feedback: (8)

I wouldn't put a wheel in it, since there is very little space in that fuse to begin with...
I'd use a dolly for launch.

ronrange

My Feedback: (20)

The location is perhaps more a function of the shape of the underside of the fuselage. Certainly ahead of the CG, locate it to provide max protection for abrasion of the fuse underside as much as possible. For example the Genie would have to be near the nose. Does that make any sense?

SoCal GliderGuider

The magic number is 15 degrees. This is from the balance point on the wings. Ahead and the tail drags. Behind and you need a skid. I don't know about towing the Mystery Ship as it has very flexable wings. Been known to get severe ailieron flutter at higher speeds.

Do you plan on using a releasable tow hook on or near the nose?

BMatthews

I would suggest just ahead of the CG right where the winch towhook would normally go and add a skid the length of the nose as per older full sized gliders. And a wire tailskid or a tail wheel of course.

Rick K

My Feedback: (6)

I have a Mystery ship, alot of things happining in the area you'd want to put the wheel, there's a former/bulkhead, a guide ramp for feeding the ail./flap wing servo wires into the fuse, the rud/elv pushrods, a 6+ch. Rx, all right there . . . being only around 1 1/4" wide inside things are pretty crowded. I suppose you might be able to manage to get a sm. (1" dia.) tail wheel in . . . I don't know, with 1/2 the wheel and ness. supporting structure for it, really tight . . . I'll go out in the garage and take a look at mine and get back to you.
One thing for sure, be sure to beef up fuse at tail 'wrist' (in front and behind the area where the LE of vert. fin joins fuse) with carbon fiber, wheel or not. This is a extreme weak point in "T-tail" designs of wood, lots of torque applied to narrow, lightly built area. A commonly known point to fracture in wood fuse. ships. (Happens ALL the time) This will be even more true when landing on two sm. points of contact, the wheel and tail. It's going to add a huge impact load to the allready high torsional load to be found there. Try to land nice and flat/level, avoid ground loops at all costs, don't stall it in . . . never, NEVER try a 'lawn-dart" spot landing or there'll be much woe and knashing of teeth on your part.
I think I'd go with the guy's recomendation of the dolly & skid method, it seems to avoid all of the problems associated with the wheel idea. Goldberg makes a neat 'wing-skid' of nylon you should look into, sm. light & effective. Iv'e used them, they work well. Tower used to carry them, I don't know know about now though.
Rick

Rick K

My Feedback: (6)

Shymal, Went out and took a look at my Mystery ship, I was wrong. There is a area (if you use a regular, bolt on tow hook or leave it off, not the wire one provided in kit) you could put a wheel in. I think the space was left to put ballast. If you placed the wheel at the 15 degree angle fwd. of the CG the other guys are recommending I think you're going to have a former/buldhead in the way if you use anything bigger than a 1" dia. It's also VERY narrow, not much more than an inch wide, it's going to be pretty tight, but I think it could be done. Use at least 4 ply, 1/8"+ plywood for wheel axle bearers, drilling all the way through the fuse sides and bearers for the axle. That should give you enough 'meat' to carry the load. Looking at the tail the fuse is even thinner than I thought and for a longer length of the fuse than I remembered (haven't flown it in a few years) . . . I predict big trouble there. As it is, just gentilely twisting the fuse back and forth causes the tail group to wobble around quite a bit. VERY risky I'd say. Use the carbon fiber, a soft tire and hope for the best, but I still wouldn't count on it being around too long. Good luck!
Rick

shyml

Thanks. I had intended to put the 1 " rubber wheel approx 3/4 inch behind the wing rod with a nose skid. That is aft of CG as i figured the tow would pull up on the nose and the glider could run along on the main wheel prior to lift off. I will now go the dolly way!

I will put 3.4 ozs cloth on the fuse weak area as suggested. I am also putting 3/4 ozs cloth on wing root D tube.

I think best wold be to buy a DG 1000 all fibre glass glider ( Czec made)

Landi

My Feedback: (1)

Hi

A 118" glider. I would just hold it in my hand run a little and tosed while the towplane starts this works just fine with this size glider or as MTT sugested a dolly is also a very good alternative.

Saludos Landi