zenoah20.jpg (21152 bytes) SPECS:

Displacement: 20cc
Bore:.32mm      Stroke: 25mm        Practical RPM: 2,000-10,000
Power Output: 1.7 HP/8,500 RPM
Weight: 41oz. w/muffler & ignition
Recommended Props: 14x6 to 16x6 Crankshaft thread size:8x1.25mm

 

ZENOAH G20 Gas Engine

I receintly purchased one of these cute little gassers. My plan is to get rid of my glow engines as they are too messy, and glow fuel is too expensive. I have owned many Zenoah engines over the years and I have never had one that wasn't reliable and economical.  Hopefully, the G20 will carry on this tradition.

The concept of the G20 is to replace 60 to 1.20 sized glow engines. To begin with, the G20 weighs 41.6 ounces complete with ignition and muffler. So let's take a look:

OS .75 AX 19.4 ounces
OS 1.20 AX 21.0 ounces
Saito 100 20.9 ounces
Saito 125 24.7 ounces
Zenoah G20 gas 41.0 ounces

So weight savings won't be favorable. Another thing to consider is power. Of all the engines listed, the OS 1.20 AX is (by far) the most powerful cranking out 3.1 HP at 9000 RPM. That's some serious power! But, the 1.20 AX also consumes lots of glow fuel! There is a BIG difference when comparing a G20 to a 1.20 AX.. If you were to replace a 1.20AX with a Zenoah G20 in the same aircraft, I think you would disappointed in the performance (by comparison). However, if you started out with a G20, I think you would be VERY happy with it. The G20 sips gasoline at such a low rate that you could use an 8 oz. fuel tank and still get more run-time than the 1.20 AX on a 20 oz. tank. There is a lot to be said about that! You can use an electric starter on the G20 if you like, but it fires up very easy with a few flips of the prop.

I put a G20 in a VQ (Global Hobbies) CAP 10 B, as a new install. So I have nothing to compare to. The aircraft is what I would call a 60 sized aircraft.The engine fit perfectly. However, the aircraft now weighs 9 pounds, 12 ounces.

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Here is my CAP running. You'll notice the velocity stack. It isn't necessary, but I like it. If it weren't for the velocity stack, the engine would be completely enclosed. The CAP 10 flies very well with this engine, inspite the extra weight. I'm using an APC 15x8 prop that turns 8800 RPM. It will also turn an APC 16x8 at 8500 RPM. The aircraft flies about 65/70 miles per hour. That's plenty of speed, and the take-off accelleration is superbe!

After some break-in time this G20 improved substancially! I also changed the muffler to a G26 muffler. The RPM is now really up there, 16x8 APC is turning 9200!  I like this engine so much, I bought another one to put in a Great Planes Super Skybolt. And it really boogies.

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During one of my receint flights I more or less raced another Skybolt which was powered with an OS 1.20AX. I easily out accellerated the 1.20 AX comming out of the turns and I held the lead down the straights. I was flying using an APC 17x6 prop that was going supersonic occasionally. I have 38 flights on this G20 and it just gets better every flight. I have to confess...  I changed the carb,  and muffler to get this massive performance. The carb is a Walbro WT-257 and the muffler is a stock one I completely gutted out. This engine spins up a MEJZLIK Carbon Fiber 16x8 prop at 9300 RPM! That 17x6 prop spins up at 9700 RPM!!! 

  My conclusion of the ZENOAH G20 Gasoline Engine is, it's a magnificent engine! While it does weigh about double what a glow engine weighs, the performance is SUPREME. Your aircraft stays clean, fuel is cheap, and a G20 flies a long time on 8 ounces of gas. You don't need an electric starter, you doen't need an igniter, and you don't pay big bucks for that messy glow fuel.

Another addition to my G20 collection, a Great Planes 60 Reactor Bipe.

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A G20 powers this aircraft beyond your imagination!