The motor that's in it now is a Moki 90. I have no idea what kind of power it makes and there's virtually no information on it anywhere. I was convinced to get the engine by a hobby shop dealer who was a Moki dealer. It's an ABC, but there's no real way to shim the head since there is no separate head button; ie: the combustion chamber and head/water jacket top are one piece. I measured the squish at whopping .022", believe it or not. Compression is good, but they only recommend 15% nitro, so that's what I've been running in it so far. Pipe is a Mac's 15cc with a 1" band and length from plug to the end of the divergent cone is about 13 1/2". Peak horsepower is supposed to be at 20,400 RPM, exhaust duration is 180 and intake/transfer is about 130, so the pipe may be a bit long. I have some 30% that I'll try in it, and if I blow it up, oh well. Balance point is 35% from the transom with 1/2 fuel. On my Stalker radar gun, it went 49.5 MPH on the first trip out after 19 years. Not good, but not set up either and of course, there's that unknown Moki factor. Didn't really play with it since fror safety's sake, I should get some new receiver batteries (no, there were no cell reversals and I charged, then loaded up the pack at a 0.5C rate and it actually produced it's rated 1000mAH after 19 years in storage). The radio is a Futaba 3PB 1024 PCM and I have a remote mixture control on the 3rd channel.
It was my first and only RC boat to this day. Since I didn't know anyone who raced these things and the internet was in it's infancy compared to today, I sort of had to wing it on my own.
After reading about them on line last week, I decided to test the waters with a CMB 90 in it so I'm getting a couple of unmodded gold heads from Allan Yuen. One's never been run and the other's just broken in. I also talked to Stu Barr, who's obviously very knowlegeable and a great guy. He's going to help me get a header and pipe combo working for it once he gets back from the Nats. I'll be starting with an X465 that's been balanced, sharpened and slightly thinned. I figure I can get the RPM without a telemetry system or onboard data logging tach by recording the pitch of the engine with the boat running directly away from me and comparing that to the pitch of it coming straight at me. I can then tell the RPM of the engine by the average pitch. Actually, since I can easily measure the air temperature, I can also calculate the average speed of the boat by Doppler shift. I'll let the computer do the spectrum analysis and the rest is easy. After that, I'll probably have enough data to give Andy Brown a call about a prop.
Ultimately, my idea was to build another cat; probably something like a Stryker F41 with one of the new Quickdraw 26 Pioneers in it. Just for the helluvit, I just ordered a Seagull telemetry system to put in whatever I build. Kind of like the sport hydros, too.
You'll have to bear with me as it's been the better part of 2 decades that I've been away from all of this, and only about two weeks on the net learning about all the things that have changed and are completely new to me.
Doug
