Hi everybody,

I hope for all of you the flying season is going well. Finally we got the Yak54 73” going with the Evolution 26, sorry for the slow flying test. Thank you to the help of our friend Scott we flew yesterday the airplane with success and we shoot some video so everyone can see the performance.

We power the airplane with Evolution 26, Evolution muffler, APC 18x6W prop (I feel like I need to play some more with props for example I will consider a 17x6), 4.8 V 1,500 mah for ignition, 6V. 1,500 mah for RX. Servos 8411 for all surfaces. Total weight 11 ¾ lbs.

Yesterday when we flew it was warm and very humid, 85 F, 90% humidity king of muggy day , not an easy day for airplanes and engines. Springfield , OH where we are located is 900 feet above sea level.

The airplane did performed very well, wing loading felt very nice, power was not explosive but enough to do nice IMAC style aerobatic and 3D. There is not power/weigh ratio comparison with my other 73” power with the YS140 sport, the Evolution is less but wing loading felt similar. The good thing with the Evolution is the engine is light weigh, so even the power is not as explosive as a glow would be but the wing loading still very similar to a glow type so the airplane still very enjoyable. Most popular situation with small gas airplane is no power and high wing loading not the best combination to have a relax flying!

Conclusion: very good combination for first gasoline airplane, not too expensive, easy to transport and very good flying. Power it is limited. It will climb out from torque roll as you can see in the video, it does slowly but steady. For other 3D maneuver such, waterfall, flat spin, harrier, harrier rolls it does very well thanks to the nice and right wing loading. If you compare this set up to a glow like YS 140, Saito 180 or OS 160 there is a considerable difference as these engines on the 73” are known as rocket power!

For those of you leaving at high altitude you know and understand performance will not be the same.

Our Evolution did run very nicely, good compression, good starting, stable and low vibration due the timing it is electronic adjusted while compare to glow the timing it is fix. So less vibration it is more noticeable at idle.. I am not trying to sale you an Evolution but I just want to do this side comment because I am sure some of you would like to know what experience we had with the engine.

Thank you guys and I hope this report and video help you out to get your own conclusion.