Do you have to change hing in the design of a C/L model to convert it to rc. The model in question is a 40 size Curtis Jenny.
Thanks Lanny Haff

I have done several R/C to C/L conversions, but not the direction you are going. I made "no Changes." Depending on how old the C/L model (kit or plans?) is, it may be way over designed and hence rather heavy. Also it will not need as big an engine for R/C because it does not have to overcome all the line drag. Some C/L models have different spans on inboard and outboard wings; make them equal. Use normal R/C control surface throws. Many C/L fliers have the CG further forward than a typical trimmed R/C model. Whatever is shown on the plans would probably be OK for initial flights.
Chuck

The plane I want to convert is a cardboard Jenny with a 60" WS. IT weighs 5lbs set up for C/L.The I was concerned about was the wing chord. Itlooks alittle narrow, but I suppose I ccan widen it a bit by installing airlerons.

Thanks Lanny Haff

You won't need to alter the wing chord. Remember that the two wing areas add up.

The bigger issues will be how to install the ailerons in the cardboard wings. For this I'd say just add strip ailerons to the bottom wing and call it good.

A .40 should fly the model just fine. Or a GOOD 4 stroke .45 to .50. By the time you modify the model for RC you'll likely add about a pound to the weight. But a 6 lb Jenny biplane will still have a decent wing loading. But depending on the airfoil it has there may or may not be some bad charactarisitics. If it didn't have a harsh stall during the glide in landing approches as a CL model then you should be OK as an RC model.

The elevator hinge is going to be fine regardless of where it is located. If it's at the scale location then you won't need a lot of surface deflection. Likely a 1/2 inch each way will be plenty. Same with the rudder assuming you use the scale hinge line location.

r8893+bmatthews Thanks Alot for your help. The plans foel came from an old issue of Flying Models + I thought it would make aneat addition to my large collection of toys. I'm going to run an QSMax FX46 in it.
Lanny Haff

I did a Ringmaster to sloper many years back.
Miserable failure.
The wing was too thick.
I tried a Flite Streak with a Speed 600 and 7 nicads.
A real dog!
OTOH, with a motor, like a .25, such planes should be really really fun!
I have a kit for the Ringmaster waiting for inspiration.

A friend told me he built a double size Ringmaster for RC. I don't recall what engine. He would take it off with lines attached with rubber bands and circle it a couple of times and then break it off and fly various maneuvers with it. An airshow airplane, I suppose.

Anybody remember the Ringmaster that was built to show off the ultra light/small Orbit radio in 1969? This was the first radio with servos that weighed 1 1/4 oz, the PS-4. They reduced the chord of the wing in the conversion and left the rest of the design stock.

I took a CL combat job called the Guillotine and converted it to RC in 1973, with a .19 engine and two channels (elevator and aileron) that flew quite well.

Other that what is noted, wasn't there an R.C. version of the Ringmaster availale back when?


Wm.

Some controline models make good conversions. Here is my Veco Thunderbird with an OS 46 Fourstroke in it.
Good stable flyer but I have spun it all the way to the ground in a flat spin as the broad wing chord and the small vertical fin make for a blanked rudder situation at high angles of attack. It will still do square loops like the controline version.

Here is another not quite conversion that I have done. This is a KenHi Panther outline that has been scaled up to 84" span and has had the tail moment increased to make it more like a 70s vintage pattern plane.
It weighs 17# with a Moki 1.8 for power and flys like a slower version of a vintage pattern plane.

I have thought that I might take the Thunderbird design and stretch the fuselage to see what it would look like.

Stunters often had somewhat long nose moments.

They often had somewhat large horizontal tail areas that were on somewhat shortened tail moments. Shortening was required in order to do the "5 foot radius" turns. Then the larger area was needed to make up for bringing the area closer.

The nose is easy to deal with. It's not obvious when you shorten 'em up a bit. But moving the tail back can be very obvious.

When I moved into R/C, I was drawing my own CL stunters at the time. My big drawing board was setup and ready to go so I drew a couple of RCs right off. Recomputing the suckers was a heluva chore. The board is gathering dust now, but thankfully, there is an online application that does the figuring in a heartbeat. And varying the numbers is realtime... like NOW... instantly done. Go to http://www.geistware.com/rcmodeling/cg_super_calc.htm if you feel like crunching some numbers.

Most of the CL stunt engines were very light, which is why them puppies sported the noses they did, especially the ones developed for Fox .35s.