<span style="font-family: Tahoma"><span style="font-size: medium"><span style="color: #000080">A little history of the YS 4s engines.
Did you know that Surer Tigre developed the engine a very long time ago!
Their concept of crankcase supercharging was the first in model avaition!
The modeling comunity thought the engine wasn't worth the effort to try it!
ST's boss sold the tooling and rights toa japaneese firm.
YS spent much time and money pushing the 4s concept.
Pattern flyers were the first to use it fully, when cu in limitations were imposed.

I'm afraid that the time frame escapes me but, it happened over 25 years ago. I can stand to be corrected!
OS tried to SC one of their 1.20s. Used a Roots type blower, engine driven, to match YS. Never did!
But OS 120 supercharged engines ARE a thing of beauty. They never achieved the HP that a YS did, and were more prone to wear.
I use YS engines and, yes, they have a sound that can't be beat and they deliver the torque!

I also like the sound of big hairy radial engines...ie PW4360 ! PW2800 ! CW3350 and the list goes on.....

POP POP POP goes the 2 stroke..... GRRRRR goes my YS !!

I love a good discussion!
M Zorger
AMA129570
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