Fuji-Imvac BT-50 EI Gas Engine
This is one of the few engines I haven't owned in my 37 years of RC Modeling. So I thought I was past due.
The engine is said to be a high RPM engine, so I attempted to locate bore & stroke information. I haven't found any of this data yet. OK, I can measure this myself, it has a 32.0 mm stroke. It is a short-stroke engine. Now I can concentrate on other aspects of this engine. If you are replacing an engine with this one, you may encounter some issues. The muffler & carb location is opposite of most other bigger CC engines. This can cause you to make additional cut-outs in your cowling as well as move your throttle linkage. In a "new" aircraft this won't be an issue. SEE: Rotating the cylinder on a FUJI BT-50 EIS ENGINE! The Fuji BT-50 EI engine is very clean and well designed as the photo depicts. You may also notice this engine uses a Walbro HDA carb. This carb (in my opinion) is the best of the best. Another nice feature is that Fuji offers various lengths of prop hubs. This comes in handy for getting prophub length in the right place without using much in the way standoff's. The Electronic Ignition is a big plus. Not only does it lower the engine weight, it also makes starting easier. In the advertisement, Fuji says it's dynamically balanced. OK, the jury is out on that one. I will just have to see how it does on my bench stand. I can do without the painted light blue jug but if the engine runs good, I can over-look the color.
IT"S SHOW TIME!
The first start:
The BT-50 EIS seems to be OK smaller diameter props. I will let it run on a tank or two before switching to a 20" prop. All indications "suggest" it will pull a bigger prop without over-heating.
Well, it's clearly obvious that "reverisnig" the cylinder doesn't effect the performance any. This engine really wants to run! The factory muffler has a nice tone and it's not overly loud either.
Here is a photo of the aircraft I am using for the in-flight tests. This is a Great Planes 1/4 scale RV-4. It really ought go! The airplane weighs 14 pounds and the BT-50 makes 19 pounds of thrust.
The muffler you see is a BENNETT made for a Zenoah G62. It's a perfect match.
Copyright © 2007 M. B. Fuess