Laser 45 vs OS 40FP

[David Davis]

In terms of power, i.e the ability to turn let's say a 10x6 prop, how does the Laser 45 compare with a plain bearing two stroke 40 such as an OS 40FP, OS 40LA or Thunder Tiger GP 42?

[Frank Skilbeck]

a 10 x 6 will be too small for a 4 stroke Laser 45 and the 2 strokes will out perform it. But if you wanted to turn a 12 x 6 then the Laser will be the better choice.

Many years ago I had a bipe that I initially flew with a Webre speed 40 and a 10 x 6 and the performance was terrible, I tried a 12 x 5 prop and it was much better but the Webra was overheating with this, so I changed the Webra for my OS FS40 (Mk1) which was much less powerful than the Webra but would easilly swing the 12 x 5, this turned out to be good match.

[David Davis]

Thanks for your reply Frank. The reason for posting is that I am trying to discover whether a Laser 45 will power an Irvine Tutor Mark 2. I know that a plain bearing two-stroke will fly one but was unsure about the Laser.

Having put up the post I phoned the Lasers and was told that a Laser 45 would power the model but that it might have a long take-off run. They recommended an 11x6 prop.

[Frank Skilbeck]

With the right prop you'll probably find it flies it very well, just make sure the undercarriage is long enough if fitting a larger dia prop.