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Would it be possible to convert from Control-line to RC?

cdfigueredo

Well-known member
#1
Some time ago I saw this model, the "Cobra" in this page, and I have been wondering if it would be possible to convert it to RC?
It's more of a question than a project, but I'm very curious about it.

This is the "Cobra". Is a really beautiful and smooth plane. :love:
Woodland07.jpg RandyCobra.gif

And this is the plan
cobra-cl-plans-feb-1971-american-aircraft-modeler-1600x1119.jpg

What do u think?
 

cdfigueredo

Well-known member
#4
I'm sure it would convert to RC - and look great too! Love the thin and graceful fuselage!
Oh yes, it is a extremely beautiful aircraft.
1m wingspan will be nice, but thin fuselaje could be a serious problen when putting the electronics inside. :unsure:.
Just adding a rudder will be necessary. I think it has a lot of horizontal estabilizer.
Must be a balsa build or 3D printed. but not think foamboard works on it.
 

Piotrsko

Well-known member
#6
We used to fly something called a junior Nobler as a glider and gas powered as a combat ship. Set up 3 channel, Bank and yank. They still make the kit, but conversion is easier with today's micro equipment. Caveat: right wing is shorter than left wing so it loops crooked but flew straight and smooth and FAST.
Didn't take long to convert.
 

quorneng

Well-known member
#8
Just remember a control line plane has a degree of auto longitudinal input and has no roll capability . It will stay at an altitude dictated by the position of the pilots arm.
An RC plane does not have this luxury so some aerodynamic changes will be required to reduce both the pitch and roll sensitivity to a level that are within the eye/hand response capabilities of a RC pilot.
 

cdfigueredo

Well-known member
#9
Just remember a control line plane has a degree of auto longitudinal input and has no roll capability . It will stay at an altitude dictated by the position of the pilots arm.
An RC plane does not have this luxury so some aerodynamic changes will be required to reduce both the pitch and roll sensitivity to a level that are within the eye/hand response capabilities of a RC pilot.
Good point. It is valid to say that it is no so simple. Some adjustments must be done to the plans. What could u suggest? :unsure:
 

quorneng

Well-known member
#10
It is worth remembering that in general "form follows function". The Cobra, like many similar, was evolved specifically for control line stunt flying not RC!

The best I could suggest is to look at the nearest equivalent in RC, aerobatic competition planes, and use them as a basis for its proportions but remember they are 'tuned' for specific type of flight and require a pilot with rather specialised skills to fly them well.
 

cdfigueredo

Well-known member
#11
Great thought. I think the best thing is how you say, to find a similar RC model and maybe make it look like the Cobra. Anyway, it's just an idea, not a project.
 

AkimboGlueGuns

Biplane Guy
Mentor
#12
The addition of a rudder would be necessary for decent performance. The biggest issue you'd have to address for a conversion from control line to RC is the short coupled nature of the design. Control line planes are designed to have an abundance of pitch control since they're roll stabilized through centripetal force. To fix the over pitching tendencies and to be a good RC flyer you HAVE to lengthen the fuselage in order to increase dynamic stability. Roll may be anemic due to the large wing area, but that can be overcome with larger ailerons, and you'll have a pretty light wing loading to begin with. Try lengthening the tail end of the fuselage by about 35% and see where that gets you. The vertical stabilizer also looks to be a little on the small side and you might have issues with latitudinal stability. Increase the size of the vertical surface as well and you should have a very nice flyer!