I have thought of buying an RCV 91, the one with the geared drive that will swing the big scale-size props. The RCV 91 in glow takes about half an once a minute, which only gives me about thrity minutes of flying time on the 16-once tank I installed in my Waco YMF-3. I plan to do some long distance/endurance video flying with it and know that ignition is a lot more efficient than glo. I wrote RCF and asked them about it and drew a blank from their rep. They hadn't experimented with the engine using ignition. I know this engine is weird in its construction, and temperamental in some aspects. Will it would work reliably on ignition and not let me down in the boondocks somewhere? Has anybody tried? Dick

Any engine can be converted to ignition....Whether a spark plug gives better economy than a glow plug is not known for sure...What is known is a regular glow engine converted to gasoline takes just as much oil in the fuel unless the big end con rod bearing is changed to a roller....When it was tried on SuperTigre engines the crank pin was too soft, leading to failure...Keith does it by replacing the crank pin with one tha't been hardened...An RCV engine is completely different inside, so unless someone wants to risk an engine to find out, no one knows...Converting to spark ignition is no big deal, a magnet in the hub and a sensor on the case...Timing would be another question, what on an RCV corresponds to TDC and how much advance does it need ?
And a Chinese ignition with a $15 Rimfire spark plug.....

So Ralf are you up for a chalenge if RTPAR wants to part with the funds?

Don';t know, Might be interesting

Hi Ralph,

Ive run big ST and Saito glow engines on gas, just for the heck of it. I found that you can run less oil on gas because the gas itself is inherently oily. They ran a little hotter and the power was down a few hundred RPM.

As far as timing the RCV, it does look interesting. AFAIK, the .91 is geared 2:1 internally. Correct me if I misremember. So that would mean it fires once per prop rotation. Whoops, no, it's the other 'way 'round. It fires twice per prop rotation. So use two magnets and halve the advance at the crank.

As far as $15 for the plug goes; what the hey, it's disposable income right? Anyway, those plugs last a long time.

CR

The SP 90 is geared 2:1 and the CD 91 is geared 1:1.

Scott

I forgot there were two different breeds of cat. Got myself confused. Shoulda stood in bed. []

CR