Help with weight and control surface choice for a converted free-flight glider

[Hogster]

Hi chaps and chapesses, got two little questions for you. :)

I bought this 52" free-flight glider this morning, with the intention of converting it to R/C, towing it up behind my 40" electric glider the Tail Dancer (http://hogster.rchomepage.com/dancer/complete/complete_main.jpg), and then releasing it.

http://hogster.rchomepage.com/ff_glider.jpg

In its current state it weighs 118g all-up - obviously waaaay too light to be of any real use at the moment. I've got two standard servos, a 1Ah 4-cell NiCd pack and a full-range Hitec Rx lying around which I propose to use in it. That little lot weighs 223g all up, which would bring the whole glider's weight up to 341g or 12oz (probably +20g for linkages et all).

I've worked out the total wing area of the glider and it comes to about 256sq inches.

My question is this - what weight should a glider of this wing-area be? Is 341g too little? Too much?

Ok I've just worked it out - with a weight of 12oz, the wing loading is 6.75oz/sq.ft .... not much. I heard somewhere that 9oz/sq.ft was good for thermalling ... this is 3/4 of that! :o

Also, which type of control should I use? A/E, R/E, or A/E/R? As you can see, there isn't much dihedral:

http://hogster.rchomepage.com/ff_glider_head_on.jpg

... so I would veer toward A/E ... This glider will be flown by my Dad who's never flown anything before, so it has to be fairly gentle, slow and graceful, but also not be too light so it could be carried away by the wind! :eek:

Any comments would be much appreciated. Thanks :cool:

[Purdue Aero Man]

I wouldn't worry too much about having a wing loading between 6.5 oz/sq. ft and say 8 oz/sq. ft. A couple of years ago I saw an article about converting these cheap foam gliders into trainers for kids and such. Some of the mods he did were to fiberglass tape the wings for strength, he permanently glued the wings in place with a bit of epoxy, tapered the trailing edges of the wings(gently) to a thinner thickness, and put small electric motors in them. I can't remember if he ran rudders with them, but the ailerons and elevators were simply cut from the wing and tail, and held in place with masking tape hinges. Should be an easy mod, and should be fairly quick to do as well. Just keep the wing loading light(6.5-8), which should keep it flying slowly enough that he can have a chance of keeping up with it. It won't handle wind too well, but you could increase the loading once he gets the hang of it by adding rudder control to the mix, or just ballast. So just start light and go from there.

[Mike Taylor]

This is a well documented conversion subject. Look here: http://www.rcgroups.com/forums/showthread.php?t=26977 and here http://www.rcgroups.com/forums/showthread.php?t=45936 and here http://www.rcgroups.com/forums/showthread.php?t=244097 and here http://www.rcgroups.com/forums/showthread.php?t=241268 and here http://www.rcgroups.com/forums/showthread.php?t=109837 and here http://www.rcgroups.com/forums/showthread.php?t=115010