ORIGINAL: �ostas
So you prefer a 4str. like YS 110FZ for speed.
Yes but i think that the OS 91FX has more power than the YS 110FZ,isn't it?
Also YS engines are very very expensive:
OS 91FX-->210$ [from Centralhobbies]
YS 110FZ-->324$[-//-]
Also nitro for YS engines is expensive too...{20/20 lower percentages}
But also
i want to ask sth else.
When the OS 91FX unloads,won't my Corsair be a speedy?
I think that it will be a quick scale warbird!
{Hangar 9 suggests 60-75 2str.}
I don't understand all the fear and loathing of the FX .91. All half dozen or so at our field run impeccably. The two I've helped set up have broken in and run exactly as you'd expect an OS engine to run. I don't doubt that the documented issues existed but I guess I'm surprised the problems weren't sorted under warranty.
The YS 1.10 is definitely more powerful than a stock piped FX .91 but the FX .91 is more powerful than all naturally aspirated four-strokes up to 1.20. See the following tests all run on the same day (four-strokes on 20/20 and the FX on 15/18 fuel):
APC 14x8 -
OS FX .91 - 9700 rpm
OS Surpass2 .91 - 8900 rpm
Saito 100 - 9200 rpm
YS 1.10 - 10,300 rpm
APC 13x10 -
OS FX .91 - 10,000 rpm
OS Surpass2 .91 - 9700 rpm
Saito 100 - 9550 rpm
YS 1.10 - 10,700 rpm
If you put a tuned full length pipe on the FX .91, it may approach or exceed the performance of the YS 1.10.
Although expensive, the YS 1.10 is a real work of art. Its power per dollar ratio is actually very good in comparison to other four-strokes.