If anyone has experience with both a stock Cox Tee Dee .049 or a stock Cox Medallion .049 and the stock Brodak .049 Mk II, how would you say either Cox engine compares with the Brodak .049 Mk II for power?
Another question I've wondered about is the lifespan of the Cox Medallion and Tee Dee engines. Can anyone comment on the lifespan of the Cox engines and the lifespan on the Brodak .049 Mk II?
Not just apples and oranges comparison, it's apples and dinosaurs. Run stock, either the Medallion or Tee Dee is much more powerful and handle (start, adjust, break in) much better. I can't speak to the long-term durability other than I know it is very difficult to fly any Cox engine long enough to wear it out, as long as you reset the connecting rod slop every few tens of hours. Both Jim and I tried multiple copies of the Mark I engine and only got one of them to run, briefly, but we couldn't get it started again, and then same thing again with the Mark II. The Mark II feels good, loose, and good compression, but no luck. Cox break-in is <1 second for the most part, it runs well enough straight out of the box, although it will get a bit better for the first half hour or so.
As far as which is more desirable, just based on what I have seen, get a Medallion or even a Cox tank-mount or product engine and some appropriate high-nitro fuel, keep everything scrupulously clean, and you will have enough power for any conventional trainer/beginner 1/2A airplane. I would not recommend the Tee Dee, it is not set up for easy running on suction, and you don't want to mess around with pressure tanks. If you want a larger 1/2A airplane, I know for certain (since I have done it) that a Medallion .049 with Cox Racing Fuel will fly a 12-ounce airplane with 240 square inches and a very thick wing with great authority.
If you want something bigger than that, I would skip 1/2As completely, and go to 15-sized airplanes, which now includes up to a full-size (S-1) Ringmaster - because the engines got more powerful.
Brett
p.s. After reading the above, with due respect to all involved, I would strongly discourage modifications, "hop-up" tips, etc. Even if they work and achieve the small improvements possible, you risk something in the disassembly and modification process, and *cox engines are built like jewels to begin with* with astonishing quality control and fits even now, much less 60 years ago. They are the only engines from the "Good Old Days" built to current high-end standards, even with old-school metallurgy. Their remarkable achievement (noted in the old engine reviews, where they marvelled over the lack of break-in required and that
a glow engine could possibly outperform a diesel for goodness sake) was controlling everything so carefully that it was nearly perfect as it came. They produced millions of these things, shoved them in a box with a plastic airplane, fuel, lines, handle, and sold it for $15 as K-Mart, and they virtually ALL worked and hundreds of thousands of complete neophytes could get them started and running long enough to crash.