I have been doing a bit of Ebaying lately and have picked up quite a few vintage OS, Enya, Merco, MVVS, Fox, and Taipan motors out of interest to see how far technology has progressed. It was interesting to run them one after the other on my test stand yesterday. I used 0% nitro on all. I used the same prop on each capacity division (15,19,29,35,40) to try to compare power between each brand. At the end of this not very scientific experiment I came to one conclusion. Hats off to all you guys that were successfully flying patterns in the 50s, 60s and 70s. Most of these motors, despite being mainly almost new in operational terms, were to put it mildly, "crap". The worst were the Mercos, talk about gutless! The most impressive was the MVVS, Taipan and Fox (in that order). The MVVS (albeit a more recent design) and Taipans were particularly well built and powerful for their size. Obviously a bench run is not going to give much impression of how they handle a stunt run but it did certainly show which motors would provide enough power while in a rich two stroke to actually pull a model around the pattern. One of the most noticeable improvements that have been made on modern motors were the NVA assemblies. Again the Mercos were awful and the Fox was ordinary at best. It must have been very difficult to get consistency out of some of these motors with such poor NVAs. About the only positive thing that I did note was that the weight of the motors hasn't changed a great deal over the years. I now have a greater respect for our "senior" flyers and an increased appreciation of my current Stalker and Enya motors. The next question is why did it take so long to get right? We finally have great stunt internal combustion motors (only took about 50 years!) but will probably all be flying electric within 10 years due to noise restrictions (if control line survives that long).

 I could not agree more. I was at the 58 nat's and got to watch the WalkerCup fly off's, setting next to wildbill. The open winners plane, twin boomed Gobbleswantz,  weighed 58 oz, flew on 70ft lines, with a Fox.35. A few years ago Lou Wolgast, built one, he felt that because it was such a large plane,
he used a ST.60.

 Walter

You mean like an ARF Nobler with a ST 46

  I am not sure that stories of fox 35's happily flying airplanes which now need a modern 60 really support the thesis that engines now are better than engines then. 

Dallas:
You mentioned runnning the vintage engines on 0% nitro - a lot of the european engines were designed to run on 0%, but when they got a taste of even 5% then REALLY came alive!  Ironically the Merco was a serious "power-up" for a lot of guys previously using Foxes (like Bob Gialdini when he went from the Olympics to the Sting Rays).  I think the MVVS and Moki(?) were popular among the European champions but do not remember them showing up Stateside.

Quite a few people had good success with K&B 45 Greenhead when it was one of the only "big" engines around - its about as powerful as a Brodak 40!

I am currently flying an ebay K&B 35 GH in a Sterling Spitfire - its like a time warp - but the combo works very well!