After testing the YS 50 ST engine, I have found it to have plenty of power while maintaining excellent fuel economy for an engine of this size. The engine also runs very smooth. Overall, an excellent motor for this displacement class.

 

I have been running this engine for months now. This new generation long stroke provides superior power when using the Hatori SB-19 over the older generation YS 91.

 

The GY240 is the perfect choice for the beginner starting with the 30 sized helicopter. It is also a great choice for electric helicopters. I find that the pirouette rate is a little slow, but very consistent.

 

The GY401 has a very consistent pirouette rate and the tail holds excellent even in the most demanding backwards flights. The best part of this gyro is its simplicity as it has no amplifier unit. I would recommend this gyro to anyone, I have complete faith that they will feel the same as I do about the GY401.

 

The GY502 gyro feels identical to the GY401 with the exception of a faster pirouette rate. The beauty of the GY502 is it gives you software options to adjust the tail control which best suites your flying style.

 

The GY611 is without a doubt the best gyro offered by any manufacturer to date. If you want the best tail rotor performance, order the GY611. YOU WILL NOT BE DISAPPOINTED!

Look for the new "Todd Bennett special" Hatori SB-19 in Hobby shops now. It makes the YS .90 SR very happy :~) Countless hours were spent making sure this exhaust was done right. If you are using the older YS 91 short stroke I recommend the Hatori SB-16 for very smooth power delivery and excellent exhaust note.