robertc
May 31, 2001, 05:19 AM
I took a 1.2 metre cabin model I had on hand. This had a low camber wing about 10% thick ( intended for electric r/c powered by a 150 watt motor) and rebuilt the wing with zero dihedral. I added a control horn and elevator linkage and gave the rudder some right turn by holding it in position with a pin. I did all the recommended things for control line such as outer wing tip weight,raking the control wires and a little more wing on the control line side.
I then placed a plain bearing speed 700 in the plane in direct drive and propped it for around 22amps current draw.
It was fed by 10 cells (Sanyo 1400mAh SCR) and I used a switch for motor control and added a 30A fuse in case of early arrival.
I had misgivings about the weight but I suddenly had a rock solid model flying on 15 metre (45 feet) lines. Not fully aerobatic but capable of flying in strong wind and doing mild wing overs in my hands.
In the hands of someone who could actually fly control line it did loops without problem.
It is obvious that given a purpose designed model and an efficient power system that an aerobatic model is possible. No mess or noise and I guess around 5 minute flights.
The subtle advantages are, as I see it - these
The speed 700 has a strong shaft that can survive the odd nose over and is cheap and robust.
The size of model this set up can fly does not require a model that has been built down to a weight that few can accomplish.
The model can have wheels large enough to take off in rough paddocks instead of bowling green type circles.
It can use regular control lines.
I hope this is of use to someone.
My next fiddle with c/l is a speed 400 model which I suspect will not be as easy a project as this one was. I admire Mike Gretz's model but I fear it would not take off on my fields with that small wheel.
[This message has been edited by robertc (edited 09-05-2001).]
I then placed a plain bearing speed 700 in the plane in direct drive and propped it for around 22amps current draw.
It was fed by 10 cells (Sanyo 1400mAh SCR) and I used a switch for motor control and added a 30A fuse in case of early arrival.
I had misgivings about the weight but I suddenly had a rock solid model flying on 15 metre (45 feet) lines. Not fully aerobatic but capable of flying in strong wind and doing mild wing overs in my hands.
In the hands of someone who could actually fly control line it did loops without problem.
It is obvious that given a purpose designed model and an efficient power system that an aerobatic model is possible. No mess or noise and I guess around 5 minute flights.
The subtle advantages are, as I see it - these
The speed 700 has a strong shaft that can survive the odd nose over and is cheap and robust.
The size of model this set up can fly does not require a model that has been built down to a weight that few can accomplish.
The model can have wheels large enough to take off in rough paddocks instead of bowling green type circles.
It can use regular control lines.
I hope this is of use to someone.
My next fiddle with c/l is a speed 400 model which I suspect will not be as easy a project as this one was. I admire Mike Gretz's model but I fear it would not take off on my fields with that small wheel.
[This message has been edited by robertc (edited 09-05-2001).]