lackeyma

My Feedback: (4)

I recently installed a RCGF 65 in a new 92" Black Horse Corsair. Last night, I fired it up to break in the engine as per manufacturer's instructions. Within 30 seconds, the vibrations had shaken out two of the cowl screws and the vertical fin was shaking so violently I shut the engine down. After removing the wing, I found all four remote receivers loose from where they were installed and one of the adjusting set screws for the Robart retract valve had left the area. The prop (22x6) was balanced. Instructions say to break it in on the plane, not a test stand, in order to allow dissipation of vibrations. Has anyone had any experience with this engine and, if so, did it shake, rattle and roll much? What can be done to tame this beast?
Thanks,

Mark

WmMiloh

Hey Bro What are you using for a mount? I have no experience with that engine but I tried to use a teflon mount for a saito 2.20 once and it did the same thing to my 1/4 scale extra 300. I had to use an alum mount to correct the prob.

lackeyma

My Feedback: (4)

Miloh.
Thanks for the reply. I'm using rigid aluminum stand-offs, the length of which is correct according to the mfg, in order to get the engine far enough forward in the cowl. Could be a "lemon" engine? Crank shaft not true or something. I definitely will not launch this thing until I remedy the vibs.

Thanks again,
Mark

rcairflr

My Feedback: (44)

Most of us who fly gas airplanes, crank up the engine, properly adjust the needle valves and go fly. I;m just guessing that you have your needle valves set very rich. On a gas engine, there is no need to set the engine rich.

lackeyma

My Feedback: (4)

Could be, thanks. I'll give it a try.

Live Wire

Ignition timing or advance of Ing. mod. Check manufacturers specks on the timing. That will shake the whole front end off your plane and a few other things[:@]

lackeyma

My Feedback: (4)

Thanks, Larry.

Live Wire

Some thing else On a big bore engine you can get vib's when the prop is out of time with the rod on the crank shaft. Combustion of engine has to force the prop through rotation causing more torque. The prop is like a flywheel on a car, with out it it will shake it's self apart[:@]

lackeyma

My Feedback: (4)

What do you do? This hub has a main bolt and three accessory bolts holding the prop. Should I try rotating the prop to the next position? How should the prop and crank be aligned? I positioned the prop at about the 3 and 9 o'clock positions so I could easily flip the engine over, as I have done with other gassers. Suggestions?

Thanks,
Mark

Live Wire

With the drilled prop you can move it a one position at a time to see if that is the problem. I usaully set my props 90 degrees from TDC. depending on how you have the engine mounted. Some times it is a prop breaking situation on dead stick landings[:@] and a trick to hand start. For more help you may want to go to the Gas Engine forum
Larry k

Joystick TX

You may want to check the spinner for an out-of-balance condition.

lackeyma

My Feedback: (4)

Actually, I've worked things out. Prop was balanced, timing was dead on 28 degrees, no spinner, went with the recommended prop size and pitch, only had to lean it out a little. She smoothed right out. I'm fairly new at gassers, but I learn quickly. Thanks to all who helped with suggestions.

Mark

Kaos Rulz

I understand about the manufactor wanting to break the engine in on the plane, however, I would put it on a test bench long enough to figure out what is causing the problem.