It seems as though there's a lot of competition in the gas engine market these days, and there are a few names that everyone is familiar with. Some of the big ones are DA, DLE, and 3W - just to name a few. There's more to the gas engine game than just them! Over the past decade, several smaller companies have sprung up - some have stayed, and some have gone away. But, just because these smaller companies may not be as well known, doesn't mean they don't have good products at good prices!
RCGF, a Chinese manufacturer of gasoline engines, designs and manufactures engines specifically for 'the RC aircraft market. They have a line of gas engines as small as 10cc, all the way up to 120cc! With single cylinder engines ranging from 10cc to 60cc, they're bound to have an engine to fill your need.
In this review, we'll be taking a look at the RCGF 20cc beam-mounted engine. With a side exhaust and rear carburetor, it's bound to fit in nearly any cowl.
Without wasting any more time, let's get the box on the table and see what's inside!
Engine Type: 2 Stroke Gasoline Engine Cylinder Displacement: 20cc (1.22 ci) Weight with Ignition and Mufflers: 1.84 lbs (838g) Weight w/o Ignition and Mufflers: 1.44 lbs (654g) Bore x Stroke: 32mm x 24mm (1.3 in x .95 in) Carburetor: Walbro-type designed by RCGF
The RCGF 20cc SBM (Beam-mount) engine arrived in a well-packed, colorful box. Now, when I say well-packed, I mean there was foam padding completely encasing the engine. This should keep it safe, no matter what the shipping companies try to do to it! With everything unpacked and accounted for, I found all of the expected parts.
The engine itself looked very nice - the casting appeared to be well done with no visible pitting or voids. A small muffler is included, and it fits the engine well. We'll see how it performs when we run the engine. Also included is RCGF's new high-voltage ignition module. This new module is capable of handling up to 8.4 Volts, meaning a 2S LiPo or LiFe battery can be used without a regulator!
The carburetor is mounted in such a way that makes pushrod connection straight forward. The choke (short) and throttle (long) arms are well placed! I removed the carburetor and visually inspected the rear of the crankshaft and lower connecting rod bearing, and all looked to be in order. The reed block assembly looks nice, and showed no signs of warpage - both reeds sat squarely against the block.
As I usually do, I removed both covers from the carb to inspect for debris - everything looked clean and in good order, so the carburetor was reassembled and reinstalled. Now, let's get this little engine installed!
Though the manual is not engine specific, it does a great job of covering all the basics - from which oil to use and how to perform the 'break-in' procedure to helpful tips on troubleshooting and safety. The manual I received was in full color as well!
Installation began with attaching the engine and mounts to the firewall. For this review, I'm installing the RCGF 20 SBM on a Seagull Models Aviat Husky. The Husky has a wingspan of nearly 80", so I'm betting it'll be a good match for the 20cc power plant. Since the Husky is also designed to work with glow engines, it has a neat little space for the expansion muffler supplied with most glow engines. I found that the ignition module fit in this space neatly, and there was enough room to pad the module with some 1/4" DuBro foam rubber. A shortened craft stick and two wood screws secured the ignition module in place.
Though not required, I added two pieces of DuBro 1/4" foam rubber under the fuel tank before it was installed. I set up the tank with a third line, and used a DuBro Fill-it fueling system. I drilled holes in the firewall for the fuel, vent, and fill lines. A short section of DuBro 2-56 pushrod wire makes as a choke rod - I left it long for now, and will cut it to length after installing the cowl.
The fuel line was then connected to the carburetor. I go to great lengths to make sure the fuel line can't get kinked inside the cowl, because it can be a real pain to fix that little mistake - ask me how I know? Back to my DuBro bin, I grabbed another 2-56 pushrod, a solder-on threaded coupler, and a pair of 2-56 ball links. I love using this setup, because it eliminates any free play in the throttle linkage. After fitting and cutting the cowl, the muffler was permanently attached to the engine. A small drop of blue thread locking compound will help keep the muffler bolts tight.
The spark plug was tightened and the plug cap was snapped in place, and all the wiring and fuel lines were secured to the firewall. With that all done, the cowl, Falcon 17x6 propeller and spinner nut were installed - It was time to get the engine running!
Propellers and Bob's Hobby Center at Steve's Hangar
Bob's Hobby Center at Steve's Hangar is the US distributor for Falcon Propellers. They offer a full product range - i.e. gas wood props,electric wood props, carbon spinners for gas and electric applications, and carbon fiber props for both gas and electric. At the 2014 Extreme Flight Challenge, 13 out of the 15 competitors flew Falcon Props!
As well as being the US distributor for Falcon and Xoar, Bob's Hobby Center is a great, full-line hobby store with knowledgeable, helpful employees. If you're in Orlando, Florida, stop in at Bob's - you'll be glad you did! You can also find Bob's Hobby Center on the web. If you're looking for a full line of high quality propellers, look no further than FALCON PROPS!
Thankfully, I have some pretty awesome neighbors. I have been running gas engines in my front yard for five years now without a single complaint. The RCGF 20 and Aviat Husky were tied down in my front yard, and I grabbed the rest of my gear to break in the engine. Per the manual, RCGF recommends a minimum of 20 minutes break-in before putting the engine in the air. So, I filled the fuel tank, powered up the transmitter, receiver, and ignition, and grabbed my trusty starter motor. For initial starts, I like to use my starter. It spins the engine much faster than I can by hand, and draws fuel to carburetor in just a few seconds.
I closed the choke and started spinning the engine with my starter - within ten seconds, there was enough fuel in the carburetor for the engine to fire! I opened the choke, advanced the throttle a few clicks and spun the engine once more with my starter. About three seconds of spinning the engine and she came to life! Thankfully, I had the tail secured, because I could already tell that the 17x6 Falcon propeller was pulling like a mule! I did have to richen the engine about three quarters of a turn on the high speed needle and a half turn on the low speed needle to keep the fuel mixture rich and the engine running. After running the first tank through, I let the engine cool down, refilled the tank, and ran it for an additional 20 minutes - just to be on the safe side.
About a week after the break-in, we had a beautiful summer's day in Minnesota! The sun was shining, there wasn't a cloud in the sky, and the wind was under 5 MPH - I brought several planes to the field and stayed for nearly 8 hours!
I filled the fuel tank, powered up my Hitec Flash 7 transmitter and Optima 9 receiver, and then powered up the engine's ignition. The engine started quickly with the choke closed (approximately 3 seconds with the electric starter) and then quit. I flipped the choke open, set the throttle to just above idle, and spun the engine again with the starter. The RCGF came to life quickly and settled into a nice high idle.
One thing I've found with these smaller gas engines is that they like to be warmed up before running at higher RPMs. I let the engine warm up for about four to five minutes before pushing the throttle past half way. So, with the engine now up to operating temperature, the Aviat Husky was freed from the starting stand and taxied out to the runway.
Since this was a maiden flight for both engine and airframe, the throttle was advanced slowly. The RCGF 20 'garbled' a little, as I still had the needles set rich. Soon enough, the engine cleared out, she picked up in RPM, and the Falcon 17x6 propeller was grabbing furiously at the air! The Husky was off the ground in no time, and was climbing upward quickly!
A couple of half throttle passes were made to trim the Husky, and it was apparent that the RCGF 20 was set rich. But even set rich and slobbering oil out the muffler wasn't enough to stop the engine from firing! Acting more like the 'little engine that could', she never showed signs of giving up. Transitions from low to high speed were better than expected for the carburetor settings!
With the maiden flight nearly complete, it was time to land. The throttle was pulled back to idle, and the Husky came in nicely. After landing, a few bumps of the throttle had the Husky turned around and heading back to the pits. With that, the maiden flight was completed for both the engine and the airframe - and both performed well!
I really like this 20cc gas engine from RCGF. Its compact size will lend to installation in small cowls, and it runs very reliably! The machining and casting work are well done, and make for not only a good running engine, but a good looking engine as well! So the choice is yours - $25-$30 dollars a gallon for glow fuel, or $5.00 for a gallon of oil/gasoline - the savings is incredible! Well done, RCGF engines, well done!
4029 E. Golden Acres Drive,
Sierra Vista, AZ. 85650
Email: firstname.lastname@example.org www.rcgfusa.com
The comments, observations and conclusions made in this review are solely with respect to the particular item the editor reviewed and may not apply generally to similar products by the manufacturer. We cannot be responsible for any manufacturer defects in workmanship or other deficiencies in products like the one featured in the review.