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Old Mar 15, 2010, 10:18 PM
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Smallest 4 stroke gas engine

Does anyone know what the smallest 4 stroke gas engine is called?

Thanks, Dan
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Old Mar 16, 2010, 01:08 AM
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You talking petrol, gasoline, benzine, ignition-fired engines? There aren't many four strokers in that category. Fuji imvac makes a few, but they aren't cheap and they aren't small. Saito makes the FG 14, which is their FA82B but set up for gas and ignition with a pumper carb.
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Old Mar 16, 2010, 04:52 AM
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The smallest gasoline powered commercial four-stroke is the Saito FG-14, .82cu.i size.
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Old Mar 16, 2010, 06:10 AM
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Now this is a small engine....how about a 1cc 4-stroke...?...and a diesel at that.....

Diesel Model Engine 1ccm Four Stroke (1 min 20 sec)





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Old Mar 16, 2010, 06:29 AM
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The HP VT21glow engine is a pretty small 4 cycle engine. .21 cubic inch displacement.
MECOA still sells them. http://www.mecoa.com/hp/vt/21.htm
Saito's first 4 cycle engine was around a .20 cubic inch displacement too, but Saito hasn't made it for many years now.
The current crop of mass produced small 4 cycle engines displace around .36 cubic inches and are made by Magnum, OS and Saito as well as the batches that Mecoa turns out in the Hp VT 21 and VT 25 engine sizes.
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Old Mar 16, 2010, 07:37 AM
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How about a 2 stroke? The reason I want a gas engine is because I live 80 miles from the closest hobby shop so its hard to get nitro fuel.
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Old Mar 16, 2010, 08:06 AM
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RCGF 15cc is the smallest gas 2 stroke

http://www.modelrcplanes.com/product..._rcgf-15cc.php

There's also the SV-17 at 17cc, but it's heavy, over 1Kg with cdi and silencer.
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Old Mar 16, 2010, 12:51 PM
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You could convert any number of weedeater, leaf blower or chainsaw engines over to RC use. if you have a lathe and or drill press you can make your own conversion parts too.
http://wackerengines.com/
But usually the weedeaters and blowers are around 24cc, 25cc or 26cc or 32cc in displacement though. But I simply go around the neighborhood and find them laying about on garbage day, so i get them free. The engines almost always work, it is the pole or something else as to why the owner is discarding them.

now one other possibility, is to convert a glow engine to spark ignition and gasoline. You have to run a higher oil content in the gasoline oil mixture as the connecting rod on the glow engines doesn't have needle bearings in it. You also have a power loss after the conversion, but other than compensating for that with a larger engine, it isn't a big deal. The early model airplanes engines were all gasoline spark igniton engines before there were glow plugs.
Here is one source for 1/4x32 spark plugs, and ignition models. http://www.prcmodel.com/modeng/name/...ore/category/7
There are many more out there.

The smallest mass produced 4 cycle gasoline spark igniton engine is the SAITO FG14, which is a 14cc displacement engine, which is similar to running a glow Saito Fa72 engine, so it should work OK for the larger 40-50 size model planes: http://www.horizonhobby.com/Products...rodID=SAIEG14B
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Old Mar 16, 2010, 01:06 PM
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About any engine can be converted to gas and spark ignition. I have seen cox .049's converted to gas. Back in the 40,s before the glow plug came out, everything was gas.
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Old Mar 16, 2010, 08:29 PM
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Quote:
Originally Posted by earlwb View Post
The HP VT21glow engine is a pretty small 4 cycle engine. .21 cubic inch displacement.
MECOA still sells them. http://www.mecoa.com/hp/vt/21.htm
Saito's first 4 cycle engine was around a .20 cubic inch displacement too, but Saito hasn't made it for many years now.
The current crop of mass produced small 4 cycle engines displace around .36 cubic inches and are made by Magnum, OS and Saito as well as the batches that Mecoa turns out in the Hp VT 21 and VT 25 engine sizes.
I can't find the price on that site. . . probably staring me in the face.

Has anyone ever seen one in use.
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Old Mar 16, 2010, 08:50 PM
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Originally Posted by Rctestflight View Post
How about a 2 stroke? The reason I want a gas engine is because I live 80 miles from the closest hobby shop so its hard to get nitro fuel.
If you're flying planes, I assume you will be going to the hobby shop occasionally right? You're allowed to buy more than one gallon of fuel at a time...
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Old Mar 16, 2010, 09:02 PM
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Originally Posted by rodneygt View Post
I can't find the price on that site. . . probably staring me in the face.

Has anyone ever seen one in use.
Look for the price list and availability page. MECOA puts a link to it on each engine page.
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Old Mar 17, 2010, 05:53 PM
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Quote:
Originally Posted by rodneygt View Post
I can't find the price on that site. . . probably staring me in the face.

Has anyone ever seen one in use.
Yes, I re-engined my KK Junior 60 (60"wingspan vintage) with an HP21VT. It flies beautifully.
The HP 21VT was the smallest production 4 stroke, it is of slightly smaller capacity than the OS20 FS.
Mine is the Austrian made version, but I believe it is virtually identical to the Mecoa version. It is very quiet, almost like an electric model in flight.
Many people believe they are lacking in power, but mine flies my Junior 60 as well as the SC30 (same as ASP or Magnum) commonly used in the same aeroplane by my cubmates.
Search my other posts for photographs of them model with the HP21VT installed.

Graham
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Old Mar 18, 2010, 12:27 PM
NM2K
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Quote:
Originally Posted by lfishel View Post
If you're flying planes, I assume you will be going to the hobby shop occasionally right? You're allowed to buy more than one gallon of fuel at a time...

No one has to go to the hobbyshop any longer. At least not anyone living in the United States. Any and everything can be purchased online or via mail order.

I stopped going to hobbyshops years ago, after I discovered that my inventory was usually better than theirs and that quite often I knew much more about the hobby than some little Hitler behind the counter.

I'm an old geezer and my latter years hobbyshop experiences were negative, as you can tell.

However, when I was just a young teenager, I used to spend weekends with a family that owned a hobbyshop. Their only son was one of my best friends in those days. Then there was his slightly older blonde and buxom sister - Carolyn. Ah, Carolyn - those beautiful blue eyes, the golden curly locks of hair, the super fine as- whoops! Can't go there from here.


Ed Cregger
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Old Mar 18, 2010, 06:32 PM
Will fly for food
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The problem with buying fuel online is that if you buy gallons, you pay $20 per case (4 gallons) HazMat fee on top of the price of the fuel and the shipping.

Or you can buy LOTS of quarts.
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