Originally Posted by AHicks

With this in the list of specs though:
"Machined Solid phosphor bronze conrod"
I'll be passing.....

While I'm not a candidate for a 9cc gas engine from any company I might support their use of a phosphor bronze rod. These size engines aren't large enough to fit needle bearings on the rod and there might not be room to allow for a pressed in bushing. So ... the rod material has to be a decent bearing material itself and phosphor bronze qualifies as that material. Saito uses unbushed special alloy aluminum rods in a large number of their engines with limited success. These can be OK in a glo engine with the high oil content but require lots of oil in a gas engine's fuel mix. Even then they are prone to early failure and the excess oil can cause plug fowling and excess carbon buildup. O.S has used phosphor bronze rods in a number of their opposed twin and a few other engines with good success so this type of rod isn't new. I have also seen bronze rods in a number of antique gas engines .... both model and large hit and miss engines. About the only thing bad about phosphor bronze is its strength and weight, but it can and has worked before with a good track record.

Well, if you solve the gas engine throttle issue for small engines, you can use the OS ultra hot heat range gas glow plug. It would work in most any engine that can use a 3/4 length 1/4x32 glow plug. That eliminates the added weight of a CDI unit and battery for the ignition system. Ifr the engine uses it there is a OS Turbo plug that would work too. They use the turbo plug on the Norvel .40 GX gas RC engine.

The problem is the extra lean air to fuel ratio that gas engines use versus glow engines. Thus the glow engine carbs may not work right. But you won't know unless you try it of course. You can use muffler pressure with the gas engines too. Anyway this ought to let you get down to .15 size engines with maybe .25 to .32 probably being more optimum for 3D types of planes. To compensate for the lower power with gas engines, you could go with something along the line of a old style fun fly plane design. Light in weight and larger wing area for slow flying. Like the one I show in the pic below with a Norvel GX 40 gas engine on it. it has about a 40 inch wingspan. The Norvel GX .40 engine is a 6.5cc size engine. With me flying slow it runs seemingly forever with the 4 ounce fuel tank.

Truckracer, we'll need to agree to disagree on the rod bearing issue. If they were able to fit them on the baby Evo engines, the technology is there. I consider this a cost saving factor on the NGH.

Earl, before sharing the fact gas power is heavier than glow, and they are down on power, you should compare the now out of production 10cc Evo to the highly respected O.S. 55 AX. Very similar weights and prop spinning abilities.

Most running these smaller gassers are running their ignition and flight pack on a single battery - without issue - for years now. I do the same thing on gassers up to the size where the plane is large enough the weight of an extra battery makes no difference....

And last, let's consider the difference in fuel tanks, gas vs. glow. The gasser uses a tank maybe half the size of the glow engine, AND in the case of the later model pumped engines, that tank can be moved back to the plane's CG. Doesn't sound like much until you actually build one. That's when you'll see that moving that tank back makes all kinds of room right in back of the firewall. Room where you can add flight pack components to get the CG right without adding ballast. -Al

Ahicks, with some planes I ran into the problem of where to put the ignition unit. It just didn't fit anywhere in the plane. So as the planes got more small the problem got worse. The Escapade .40 is one example where I ran into problems. The CDI unit wound up underneath the engine up front. But like usual it depends on the airplane design.

Thus having the means to not use the CDI unit is a plus as the planes and engines get smaller.

I have a couple of the 10cc Evo engines and I do enjoy them too.

Yes I like being able to move the fuel tank back with the engines that have fuel pumps on them. But not all small gassers have fuel pumps.

Originally Posted by AHicks

Truckracer, we'll need to agree to disagree on the rod bearing issue. If they were able to fit them on the baby Evo engines, the technology is there. I consider this a cost saving factor on the NGH.
. -Al

I didn't say I liked the idea of using a bronze rod, just suggested they have been used before with success and by some large companies. Saito engines which are anything but cheap continue to use unbushed or bearingless rods in many of their engines while using the excuse it allows for a narrower crankcase. Perhaps NGH uses the bronze rod for the same purpose. Its really a non issue with me as I no longer buy Saito and I won't be buying a NGH anytime soon.

One local flyer had a first generation Evolution 10 that I thought ran quite well. He sold it quickly though as he just couldn't adjust to placing the ignition module and the plug cap / cable. Also couldn't adjust to the gasoline odor in his car which I thought was a controllable issue. Gas just isn't for everyone.

Originally Posted by earlwb

Ahicks, with some planes I ran into the problem of where to put the ignition unit. It just didn't fit anywhere in the plane. So as the planes got more small the problem got worse. The Escapade .40 is one example where I ran into problems. The CDI unit wound up underneath the engine up front. But like usual it depends on the airplane design.

Thus having the means to not use the CDI unit is a plus as the planes and engines get smaller.

I have a couple of the 10cc Evo engines and I do enjoy them too.

Yes I like being able to move the fuel tank back with the engines that have fuel pumps on them. But not all small gassers have fuel pumps.

Finding room for the ign. module is a different issue than being heavy or down on power. I agree there is a certain"wad it in there" attitude required, especially with that skinny cowled Escape. I did manage though, even on that one. Sometimes you don't need all that spark plug wire......

That was one of the planes where I had the ign. module, the receiver, the battery and the throttle servo in about the same size area as my fist - debunking the often quoted need for a lot of separation between those components. That separation is nice if it can be arranged, but all is not necessarily lost if you can't. Just be careful on your range checking.... -Al

Originally Posted by Truckracer

I didn't say I liked the idea of using a bronze rod, just suggested they have been used before with success and by some large companies. Saito engines which are anything but cheap continue to use unbushed or bearingless rods in many of their engines while using the excuse it allows for a narrower crankcase. Perhaps NGH uses the bronze rod for the same purpose. Its really a non issue with me as I no longer buy Saito and I won't be buying a NGH anytime soon.

One local flyer had a first generation Evolution 10 that I thought ran quite well. He sold it quickly though as he just couldn't adjust to placing the ignition module and the plug cap / cable. Also couldn't adjust to the gasoline odor in his car which I thought was a controllable issue. Gas just isn't for everyone.

So we do agree that neither of us will be ordering that engine any time soon.


I might be will to try it on a trainer or something, but not in an application where I'm needing/trying to get max available power out of it. -Al

Regarding small gas engines in the 20 size, I really enjoy my DLE20s! In the past, I've had an assortment of 90 - 120 sized glo engines but prefer the performance of the DLE20 far better than any of these glo engines. While the glo engines may be more powerful in terms of peak HP, the 20 excels in torque and its ability to turn a more useful prop size. The DLE is very user friendly and just plain enjoyable to fly. I'm sure similar sized engines from other companies offer a similar experience.

I see where Gold Wing is now offering some 20 sized planes but I don't know who sells them in this country. As suggested before, Pilot also offers them.

Several companies offer 30 - 35 sides airframes.

I remember a few companies offering .21-.32 size gas engines for RC cars and Boats. Some actually sold a complete RC car with them in it too. So there are some precedent for .21-.32 size gas engines out there. So it may be possible to set up a .20 size plane with a gas engine in it.