Parasite R/C Gliders

To all,

Does any one know where I can find some useful information on this subject?

I am currently flying a Multiplex funjet on F12 and G13rc reloads and thinking of taking the plunge on launching it on a booster ( a la Space Shuttle) then releasing the glider, then during the descent light the motor in the Funjet for a second bite of the apple so to speak.

The flying wieght of the funjet with motor loaded is 840g (about 20 something ounces in american currency) and a wingspan of 31.5 ". I do not need altitude as this glider is already getting too small to see at the 850ft of the G reloads.

I do have a copy of rocksim to play with, but haven't worked out how to dial in the glider. It is moulded polystyrene.

I'm thinking of a 39" long 4" diameter tube as a starting point for the booster.

I would be inerested in hearing from any one that has tried this. Will I need fins on the booster? or could I still steer the whole composite using radio control for the ascent? Is there a relationship between the CP & Cg of the booster and glider that I need to consider?

Thnks in anticipation

Planecrazy

The fun jet has plenty of wing/fin area to make a booster stable, so you shouldn't need any additional fins. The key with something this size is to make sure that your attachment is rigid, but still able to release the glider at apogee.

There shouldn't be any need to steer on boost, just make sure the CG is a chord-length or tube diameter (whichever is greater) ahead of the level flight CG and you should be good to go. You can also dial in a little bit of roll on boost for some additional insurance.

There are other tricks that you can use to make it fly better, but aren't entirely necessary. According to Multiplex's website, the Funjet weighs in at 31oz. I imagine your rocket powered one is lighter, but not horribly so. You can consider offsetting the booster motor to coincide with the total CG of the booster/funjet combo. This will make for a slightly nicer boost profile.

Also, I would build in an R/C release mechanism for something this size. No sense in wasting flights where the glider hangs on the booster, right?

Oh, and don't fly into the parachute.

If you want a rough simulation treat the glider as a large fin set in Rocksim. You could also do a cardboard cut out of the rocket and glider to figure out a rough CP and adjust your CG based on that.
Also check out the relative sizes of boosters for gliders like the Estes F-22.

You definitely will want some sort of attachment at more than 1 point. Something at the nose and 2 more at the back under the wing that form a triangle would be my take (look at the Estes Space Shuttle instructions for an example and scale it up to suit your needs).

kj

Cheers guys

Some good food for thought. The plan has always been to get an R/C release, this will help avoid the flying into the parachute scenario.

My thoughts on mounting are a two point connection with R/C release and some sort of sway brace to stop any unwanted rockin' and rollin'.

Thanks again I'm of back to the shed for more R&D, and maybe a beer (Thinking juice)

Planecrazy