I've heard that Jett engines are truly phenomonal, but I've never seen one up close (I think they're a little too rich for me and my flying buddies ). Another question I have is who in the world uses a 10x6 on their 50 sized engine? Or a 12x6 on a 91? Are Jett engines tuned for the ridiculously high rpm figures found on their site (17,000 for the 50 and 14,700 for the 90)? How would a Jett do with a prop that most of us would fly with (say an 11x7 or 12x4 for the 50 and a 13x8 or 14x6 for the 91? Does it change any of the characteristics of the engines? For me it's substantially more important that me engines be able to chug along at good rpms with a bigger prop (equating to greater thrust) than hit warp speed with a smaller prop, but then again I don't race any of my planes...

I've only been in the hobby for 3 years now, but I've run a wide array of engines. From my observations (at least for 2Cs), most of the Asian engines (including OS, TT, and Magnum), are interchangeable, in terms of power and user friendliness, given similar displacement. They also are designed for at least some nitro as most of mine like at least 10% and run better with 15-20%. The European engines I own (MVVS, Rossi, Webra) all have substantially higher compression which allows them to work well with no nitro. They also tend to be a tad more powerful than their Asian conterparts.

In terms of 4Cs, YS's are really something else (I only have a 91, but it's a monster), but require 20% nitro, which gets expensive if you fly often. Otherwise I've found that Saito's are lighter than the competition, but require at least 15% nitro. Magnums are cheap, but I've found that they usually run within a couple of hundred rpm of their OS counterparts which makes them a bargain (and they only need 10% to run well). They even look like OS clones, I'd be wouldn't be surprised if Magnum is reverse-engineering all of OS's latest models when designing their own. Thunder Tiger supposedly hired OS's chief engine designer a while back, but they've only released two 4C models to date. I've got a 91 and it seems to be as strong (if not a little stronger) than my OS 91, but took about a gallon to break in and is a couple of oz heavier than the competition.