In response to your two points:

1) I can't give you an exact part number for the adapter, and if I could you really shouldn't use the number anyways. The guys at CH know all about the Precision Eagle 4.2, and that it was built over the years with different drive shafts, with different tapers.

Before calling them, measure the diameter of the shaft right behind the threads, then again as far back as you can. With these measurements alone, and mentioning that the adapter you want is for a 4.2 they'll be able to suit you up.

If you send CH your engine, they'll pick the right adapater, determine where the magnet needs to be insert, drill/ream the magnet hole and install the magnet. They'll even tune th engine for you - but you made need to retune it when it comes back due to altitude differences. Their located in Wyoming - so they may be higher or lower then where you're located.

I located my own magnet hole and did the drilling/reaming myself - no problem if you have drill press and place to buy reamers from.

CH was very helpful - you'll do fine with them. Oh, they'll send you a magnet too, so no need to worry about the ones buried in your other adapters.

Have been told by a number of people that the Byron props will fly the plane - very 'scale like.' I'd rather have the extra power available to me if I need it, and if I then want to make take-offs very 'scale like,' I'll just throttle back the engine.

I rarely run anything a full throttle for very long, but its nice to know you've got extra power available if/when I need it.


2) Its an 87 inch wing span. 4.2 cubic inches works out to 68.8 ccs. The G62 is listed as a 3.8 cubic inch engine. Have had recommendations to go smaller, and some have said the 4.2 should be hitting 6200-6400 RPM with no problem.

I have tried a 22x10 and have gotten 7K out of it. And, I will certainly consider it for at least the first flights. However, my main concern is that I have not been able to get rated RPM of out of the engine for the props spec'd in the manual. A number of others have agreed that the spec should be achievable, unless something is wrong. I'd like to hit the specs by finding out what is wrong and fixing it before flying.

Today, I decided to tear the carb apart to check the gaskets, diaphragms, filters, etc. Found a bit of dirt, but not enough to be worrisome. I also noted that one of the diaphragms has a metal plate with a pin on it that is supposed to be inserted into a spring loaded lever within the carb. Now in taking it apart, I did not notice whether this pin/lever had been assembled properly or not.

So, I put it back together, correctly, and tried it again - I gained another 300 RPM, now hitting 5800-5900 and sometimes peaks of 6000 RPM. Between this fix and the Zinger prop, I've gained 900 RPM.

My carb is Walbro WJ1D C-4. I want to get a carb kit for it so that I can compare the condition of new diaphragms with those in my carb - mine feel a bit more papery than I expected, but then I don't have a benchmark to compare them against.

I had the carb off once before, but had never disassembled it, and it had always been running several hundred RPM low - so I must assume that the carb had been misassembled somewhere in the manufacturing/pre-ownership pipeline before I bought it. It always ran great at idle/low/mid-range. Transitions and high range were fine, too, just not high enough.

I don't know the function of that spring loaded lever that the diaphragm attaches to. However, I recall reading something about the function on website dedicated to carb maintenance on Ultralight Aircraft engines. There are some adjustments that can be made - will have to find this site again. I expect this lever helps keep the diaphragm pumping action in sync with the engine - it appears to keep sync fine at lower RPMs no problem, but needs an assist at high RPMs.

Changing the spring setting must have something to do with changing how far the diaphragm moves for a given pressure differential - not something I'm going to change without learning more, first. I expect that if the needle valves were ineffective, then there might be a problem with this diaphragm not moving enough or moving too much due to a spring problem.

Must run. Sorry, must fly! Here's some more pictures: