I can't say that I am pleased with some of the features of this new engine. First, the weight shown on the OS Web site is a contradiction. 647 grams divided by 28.35 grams per ounce works out to 22.82 ounces, not the 20.88 ounces shown on the OS Web site. I would think that the OS engineering staff can do better than this, so I'll blame their marketing department [8D]. I would tend to believe the higher weight of 22.82 grams because the OS .91 FX (25% smaller) weighs 550 grams or 19.4 ounces. Here is the link for the OS 91 FX:

http://www2.towerhobbies.com/cgi-bin...?&I=LXBY47&P=0

Second, five cylinder head bolts rather than six or eight bolts is a cost-cutting measure that results in more profit for OS/Futaba, not a better compression seal and longer lasting engine for the modeler. The OS 108, one size smaller, has eight head bolts:

http://www2.towerhobbies.com/cgi-bin...?&I=LXCK26&P=Z

While the OS 140 RX, one size larger, has eight cylinder head bolts:

http://www2.towerhobbies.com/cgi-bin...?&I=LXCK25&P=Z

and the OS 160 FX has six cylinder head bolts:

http://www2.towerhobbies.com/cgi-bin...?&I=LXUT09&P=Z

Third, even if this engine were to sell at a whopping 40% off MSRP or $270.00, it would still not be price competitive with other excellent engines in this class such as the Moki 135, Thunder Tiger 120, Webra Speed 120, etc.

Fourth, the standard muffler appears to be a copy of the Thunder Tiger 120 two-way muffler, but from the picture, it seems to extend pretty far down and could be difficult to enclose inside some cowls such as that found with an Extra.

To OS's credit, they finally moved the 120 AX needle valve to the right location.

Bruce