A Cheetah chuck glider conversion.

[quorneng]

The Cheetah is in the same category as the Lidl chuck glider. It is slightly smaller (and cheaper!) but has a rather more 'elegant' appearance.

The wings of the Cheetah have considerably less area than a Lidl so I decided to gain the area by extending the wing span by adding a new centre section so increasing the span by 50% to 1.3 m!
As I did on my Lidl I also increased the chord by adding 15 mm trailing edge extensions to give the wing a fine edge. Three 3.7 g servos work the elevator and ailerons. It is flown bank and yank.
A small 40 W motor driving a 5x3 folding prop, a 10A esc powered by a 500 mAh 2s completes the conversion. It weighs just 192 g ready to go.

Always intended to be a powered glider rather than a power plane. In calm conditions it flies and glide very nicely.

It is pretty quiet too. Turn up the volume on the video and you can hear the birds singing!
That 3 minute flight used hardly any of the battery capacity. A flight of 30 minutes should be possible.

 

[IdoAllMyOwnStunts]

Wow! Looks amazing! flies smooth. Nice work.

 

[Hondo76251]

I picked up a few of those myself, have yet to convert one. Did you have to reinforce the wings or fuselage?

 

[Tech3811]

Looks great!

 

[quorneng]

No reinforcement anywhere.
The new centre section, with printed ribs, is skinned in 2 mm Depron which is actually quite dense and strong so creates quite a stiff structure.

It has no spar as such just a printed shear web between the ribs at the point of maximum thickness.
The original foam wings are relatively more flexible but have the aileron servos in them so are only taking about 50% of its 190 g all up weight, about the same as when a chuck glider so are quite adequate.
The elevator uses external pull/pull wires (nylon mono filament) with the servo buried into the fuselage under the wing so the rear fuselage is unchanged.

The ESC, in a printed tray, is let into the cockpit wall so gets adequate cooling.

Leaving just the battery and micro rx in the cockpit

The motor is inserted into a slightly built up nose.

With a cooling intake on top and side cheek outlets.
In the right conditions (very little wind!) it is a joy to fly.

 

[bracesport]

@quorneng - I did a Pitcheron mod to the Cheetah - I ended up building a new wing (cutting down a Bixler3) as the original Cheetah wing was twisted.

 

[quorneng]

bracesport
That's very neat and well engineered too although it is perhaps stretching the concept of an 'RC conversion' of a chuck glider.
I know my conversion went a long way too but I did at least retain all the original parts except for the foam that was dug out.
I even kept that.

 

[bracesport]

@quorneng - Ok, here is a simple conversion - another chuck glider, this time 1.2m EPP converted to ailerons and elevator! 😁

 

[quorneng]

My Cheetah RC conversion suffered a rather hard arrival which severely damaged the built up wing centre section extension.
Rather than rebuild it I chose to revert to using just its original foam wings which were undamaged.
This would mean a significant 40% reduction in wing area although there would be a small weight reduction from 198g to 189g. The wing loading would rise by 32% so it will fly a bit faster.
The rest of the Cheetah conversion would be basically unaltered.

One change was to use a printed now cowl of slightly reduced size that would allow the blades of the prop to fold better.

The other modification was to add thin (0.35 mm) printed spar 'flanges' 200 mm long glued to the top and bottom wing surfaces at the root to reduce the quite alarming wing flex. Not that surprising as in it original form as a check glider it weighed less than 90g.

An additional 'sub' spar was added to counter the effect of the aileron servo cut out.
Even with the reduced span it is still more of a glider than a power plane.
A video will follow as soon as the weather calms down a bit.