Rubber Kit conversions

[esox]

I'm new to electric flight and VERY new to electric Microflight. I love the old stick and tissue style planes and I'm wondering how well these kits convert to small rc.

For instance, I have a Sig Monocoupe 24" span rubber power kit (stick and tissue) that I've been planning on putting together for ages. I would love to build it for electric power and 3 channel control (likely elevator, rudder, throttle).

http://www.sigmfg.com/images/SIGFF25.jpg

This particular kit seems to tend toward scale details and I'm afraid it will be heavy. What do I need to consider changing from the plans in order to get a decent flying micro RC plane?

Would adding a slight undercamber to the airfoil help?

Should I add a bit more dihedral to help in rudder control?

I'm sure I can lighten up the airframe a bit. For example, the wing has ribs about every inch. Is that excessive? Also the cowl and wheel pants could be made by laminating depron instead of the stacked balsa sheet.

Im not sure what the weight of the finished model will be, but in general, what power system should I expect to use?

If this size and type of model can be built to fly well with rc control, I will be a happy little modeler indeed! :)

Thanks,

Jack Wheeler

[ 06-04-2001: Message edited by: Jack Wheeler ]

[Jason Nowell]

Jack:

I've played with progressively smaller and smaller stuff over the past year. You are definitely right about adding a slight under-camber to the airfoil. Also the dihedral is a VERY good idea if you plan on flying indoors.

On my 28" Stearman (from a Herr kit) I left the bottom spar out and only covered the tops of the wings. It worked well for easy under-camber, but I tried the same thing on my Fokker D-VII (but left the bottom spar in) and it just created a bunch of drag. The airplane never seemed to get up "on step". No matter how much power you added, it just slugged around barely hanging in the air.

I think the plane you picked is perfect, the 24" span is right on the edge of about 3 different power systems that I know of.

I did a Cox Highway Patrol plane (22" Cessna type foam job). I used a GWS A (Lite Stick)motor direct drive with a 4" prop (the red plastic ones that come with most electric free flight planes these days). It flew very well, I used a GWS reciever, HS-50 servos, and GWS ESC. I used a 6 cell 50mAh pack that gave me about 2 minute flights.

I now use the new 120mAh Nickel metal Hydrides (7 cell) that weighs LESS than my old 50mAh pack and gives my 4 minutes at full bore. I got it from Dan Kreigh (Mr. IFO) and i beleive he sells them online.


You might also think about trying the Dual N-20 gear drive setup from Bob Selman Designs (or similiar).

A Stick motor in it's gear drive would also work, maybe one of there new 7x6 or 6x5 props....who knows.

Hope that helps you out.

[ 06-04-2001: Message edited by: Jason Nowell ]

[Blackhawk]

Jason

I too love the stick and tissue types, but I haven't yet tried anything quite that small (24 inches)-- I did blow the 22.5 inch Velie Monocoupe up to 30 inches (150 square inches) and powered it with a Puma 050 and 8 small NIMHs (36 grams for the battery pack) and have a great flyer that will go up to 10 minutes with judicious use of throttle. Why not blow up the Tom Stark designed Monocoupe to about 30 inches and have a little less wing loading. My Monocoupe was 180 grams, but if I did it again, I am sure I could do it for 160 grams. My monocoupe is on the photo pages--now has over 500 flights and still going strong. Best of luck and keep us informed.

Pat

[esox]

Jason,
So what you're telling me is, I now have an excuse for buying a lite stick and GWS flight pak to play around with while I build this thing? :p

Jack

[losiboy]

I dont see how you guys can build those little stick models, I try but it seems if you look at it the wroung way a little stick will break, im must be a klutz

[esox]

hehe losiboy,
you have to look at them just right. :)

[Jason Nowell]

Jack:

You can always have fun with a Lite Stick!!! My record for small is 22" span (that flew). It had a very thin chord also, so I think 24" with the thicker chord like yours will work fine. It won't be a floater, but it'll manageable indoors and out on CALM days.