Old designs

[Terence Lynock]

Started out updating an old F/F plan from the 1950;s with twin rotor and originally a I/C motor, the rotor is a twin 27'' unit, will this lift 700 grams ready to fly and how much electric power do I need up front??.

The rotor is two three bladed at an angle of 5', the unit is basic running on two ball races so very little friction.

[Tom Wright 2]

That's interesting Terrence,some good free flight designs were around in the 50s .I am assuming this one has the rotors mounted just inboard of the wing tips ? Sounds like it would fly with 150-250 Watts.Do you have a photo?

Tom.

[Terence Lynock]

Hi Tom,

the rotor is a contra-rotating unit of 27'' diameter, basically a length of 1/8 piano wire with brass tube spacers,the bearings are flanged ball bearing races soldered into the centre of two 10mm I/D washers with the blade mounting wires also soldered to the washer,

The fuze design left little space for ESC, R/X and other bits but it will go in, I may have to make a little extra space somehow if I need to fit a bigger ESC if I have to uprate the motor.

At present with a 100 mha 3S the finished weight ready to fly I would guess at 700 grams or maybe slightly heavier but not a lot, as long as I know the rotor will lift the weight I can experiment with the motor and prop.

 

best regards. Terry

Edited By Terence Lynock on 13/11/2012 23:49:52

[Tom Wright 2]

Ok got a better picture now ,it does sound like an interesting design .A bigger lipo will be needed I think.

Regards

Tom.

[Tom Wright 2]

Terry I guess your model is not to unlike this modern version.

 

Tom.

Edited By Tom Wright 2 on 14/11/2012 02:00:16

[Tom Wright 2]

A motor like this should be ok ,and and an ESC like this to go with it .The lipo needs to be comfortable delivering 15 amps so if there is room a 1.5 A three cell would be ideal.

Tom.

Edited By Tom Wright 2 on 14/11/2012 02:21:10

[Terence Lynock]

Problem is Tom that the fuze is a very slim design meant for freeflight so no room to spare at all, I can just get a 3S 1000Mah 20C in and nothing left, swapped the original ESC for a 25A and have a 2212 motor that will give me 185w running a 7x6 sport prop.

Why is it that allen keys inncluded with stuff from China are pretty good but the grub screws are soft and innacurate? my next job is to drill out two grub screws frpm the back/plate of the Emax 2212 so I can put the motor on a new backplate.

You have to reemove the backplate and screw this to the bulkhead first then fit the motor to the backplate with two grub screws which means poking a hole in either side of the fuze to get at the grub screws,stupid idea really.

[Tom Wright 2]

Terry

The 1660 KV E max motor will almost sound like a busy little diesel .Yep the grub screws can be a pain ,but can be fixed . I recon the 1000 ma lipo will be fine with that motor.

Do let us know how things go.

Tom.

[Richard Harris]

Terry,

I have a few free flight plans that I have collected, non are conta rotating so I would be interested to know what it is?

I have seen an Al's Gyro flying and the one thing I can recollect is that they almost always fly with there tail down.

Plans for that are available through MyHobby Store in their X list section HERE

Have fun with your project.

Rich

[Terence Lynock]

Hi Richard,

I found the plan for this one, Contra-Giro, on www.outerzone.co.uk, the site holds about 3,500 free plans and no rubbish unlike the Aerofred site, it has four or five autogyro plans worth downloading.