Engine for Maxim

[John Minchell]

I have a 72" span Maxim model which used to fly with a 20cc fourstroke glow motor - YS / Yamada or something.

I aquired the model without servos or motor. 

I wanted to put a spare ST2500 in it but with 6x standard 60g servos and a motor weight of 1.2kg it will put the OA weight to 5.3/5.35kg which is over the limit for your UKCAA competitions.

Does anyone know the weight of say a 120 ASP or SC or some such similar 20cc 2 stroke motor (with and without silencer) which I can get hold of easily (money is tight too, so likely second hand) and with some 30g servos I can squeak under the 5kg limit?

 

TIA John M

[Don Fry]

Asp 120 AR weighs in at 935 grams. Nice motor,I have one in a hack.

Hobbyking corona servos are good. Their High Voltage units punch well above weight.

 

935 is with silence, 850 without

Edited April 11, 2021 by Don Fry

[John Minchell]

Thanks Don - gives me something to go on.

What size & pitch prop does the ASP 120 turn?

 

John M

[Don Fry]

It’s in a ARTF 90 size Stick. Weight is about 4.5 kilos. It looks like I’ve got an APC 16 x 8 fitted, can’t be absolutely sure without taking the spinner off, 

The airframe came to me second hand. It had previously been fitted with a Supre Tigre 2500, what was a constant pain to the previous owner, so I sold him the ASP to get some reliability. It has a lot more authority with the ASP. Unlimited loop size, constant speed. 
Are you planning to fit as is, or on a pipe?

[Don Fry]

Just dug a 16#8 APC out of the spares box. That is what’s on the motor.

[John Minchell]

Thanks Don - dunno what I'll do yet, it depends on what motor I can find at the right price etc. 

As I say I have a brand new in box Super Tigre 2500,but it's way too heavy.

As long as a good 120 or 108 2T will fly the model, then hopefully I can find something cheap but a good runner.

[Don Fry]

Did you just buy a ASP 120 AR on E bay. A decent looking example just went through for stupid money, just over £30 plus post. That is a lot of power per pound. 

[John Minchell]

Hi Don - no it wasn't me, but I have a good mate who is sending me a new, unrun ASP 120 with silencer for £50. 

I thought that was more sensible than a used and possibly abused engine from ebay.

Thanks for your help.  John