A .90 SuperTigre on Gas?

[JayB]

Just stumbled across this, was thinking of getting it to put in a F90. Good Idea or bad Idea?



The New BME G90 Gas Engine ... a .90 SuperTigre on Gas!

Announcing the new BME G90 Engine... the first quality/performance gas engine this small ever made. The .90 engine is the same size and weight as the .60 and .75 so why not go for a .90 get more bang for the buck?
The new engine is a gas conversion from a SuperTigre .90 glow engine, so it comes with all the history and reputation of the SuperTigre engine line, combines with the engineering expertise of BME Engines... Quality you can trust with robust construction that will last a lifetime.
The G90 runs on 50:1 gas/oil mix, so it's economical to operate. Ten ounces of fuel will run 30 minutes at full power. The fuel savings alone will pay for the engine in a short period of time. Plus, there's no oily mess to clean up. You get a custom built BME crankshaft, connecting rod and piston (needle bearings for gasoline/oil mix). A custom modified crankcase and housing from BME as also in order for optimum gasoline operation.
Because BME uses a Zama pump carburetor, you can now mount your fuel tank anywhere... the carb will pump fuel just like all other gas engines, much better transition and no dead sticks. Experience the ease of electronic ignition... easy to hand start with no glow plugs or glow drivers, and no field box full of support equipment. Get no weight penalty since the engine weighs about the same and the ignition with battery weight is offset by the reduced fuel tank capacity required. The G90 is supplied with a stock muffler.
No more rusty bearings as with glow engines (gas and oil are natural lubricants and do not absorb moisture from the air as glow fuel does.) More power and a larger carb, electronic ignition and special BME modifications all add up to an engine that has no power loss and is like a .60 size plane on steroids.

[JayB]

On second thought it may be a little small for a F-90. What plane would you put this motor on?

[green@3D]

Gasser F40!!!!

[Edge 540]

Yeah, a 90 glow is pretty small for a funtana 90. The gasser will have less power..not gonna help any! It would help fuel prices, but I think .90 is simply too small for gas. I think the smallest gasser I'd bother with is a 40cc. There are sooo many planes out there for the 50cc size though. Less than that,....I would just go glow.

[Boulder]

Same weight as a 90 2-stroke! Swings a pretty big prop! Good candidate for a Katana 70,.

How can you argue $3.00 for a gallon of fuel in comparison to $18.00, and twice the fly time per gallon?

[dick hanson]

the Harrier is about right -really light and about right size
you would have to prop it to rev pretty well at least in the 9000+ -but should work whatever -for sharp performance -work at weights in th3 single digit range
6-7 lbs-if possible
My Funtana 90 is 9.5 with a piped 1.6 and that is excellent 3Dsetup but 1.6 is a lot larger than .90

[Chris Puckett]

I looked at those motors for my P-38 but have decided to go with the new little Zenoah 20. First Zenoah with a electronic ignition

http://www.horizonhobby.com/Products...rodID=ZENE20EI

[Edge 540]

Will a G90 gas conversion really outperform (power wise) a glow version? Maybe I'm all wrong.

[dick hanson]

this is a question that can be answered two ways - yes and no
Basically: gasoline has more power per ounce than alky
So-a gas engine would seem to obviously make more power .
But gas has to be mixed with much more air than alky to burn properly -also it is more critical in this mix ratio.
as a rough comparison --it takes twice as much alky to deliver same power as gas
Here is where it all gets changed.
the alky is very tolerant to mix ratio and will also mix readily with nitromethane (which brings along it's own oxygen to the party)
The gas mixes in a ratio of 1 ounce gas to 13 ozs air -- the nitro/alky mix can be all over the place at one ounce fuel to 4-7 ounces of air.
An engine can only gulp a fixed amount per cycle (total intake volume of air and fuel)--.
the result is way more than double the amount of alky,vs. gasoline comes in
that's where the glow engine makes the extra power .
still puzzled?
look at the relative amount of fuel tank size needed for alky setup vs gasoline.
15 years ago at the TOC-we were faced with this fuel problem--
the engines available for gasoline were heavy converted industrial engines.
we opted for lightweight glow engines and used big fuel tanks-to get the power needed
Today , there are well designed ,lightweight gasoline engines -allowing the use of less fuel .(The prices of fuel are another issue) so we now have very good power to weight
When you get down to small ignition engines-such as the .90-- the TOTAL weight for power output gets to be an issue but the gasoline setups are really cheaper to feed and once properly setup- simpler to take flying
all my gas engines start very easily- and fuel costs -per power output are less.

[celery]

Anybody have some good info on these engines? I have searched just about everywhere and have not found anything, I would really like to know what size prop they spin, will they spin a 15x4 wide apc? and if, what kinda rpm. I would love to install this in a fliton edge freestyle. Any good info would be great.