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 15cc, all the way up to 120cc! In addition to the vast size range, RCGF has a number of twin-cylinder engines as well - 30, 40, 60, and 120cc - all are a 'boxer' type, meaning the pistons travel in opposite directions to minimize load and balance concerns. This, in turn, also reduces vibration.
While RC gas engines have been around for quite a while, the demand for high quality twin cylinder variants is fairly recent. But these twins have come a long way in a short time! The RCGF 60cc twin is relatively new on the market, but definitely fits the 'high quality' definition.
Engine Type: 2 Stroke Gasoline Engine Cylinder Displacement: 60cc (3.6 ci) Weight with Ignition and Mufflers: 1690g (60.3 oz) Weight w/o Ignition and Mufflers: 1380g (49.2 oz) Bore x Stroke: 38mm x 28mm (1.49 in x 1.1 in) Carburetor: Walbro-type designed by RCGF
Though the complete line of RCGF engines is available through BP Hobbies, my engine was shipped directly from the factory in China. The box showed some signs of rough handling, but several layers of foam padding inside the box kept the contents safe. I pulled all of the parts from the box, and took inventory - everything was in great shape!
My first impression of the engine's looks are good - there's some tool marking on the exterior of the crankcase, but it was nothing I was concerned about. The casting on the cylinders looked great, and there was no signs of pitting! The 6-bolt propeller hub looks great, and lends itself to a very scale appearance.
The radial engine mount is well machined and looks sturdy, and the included aluminum standoffs and hardware are first rate! The ignition system is designed to operate on 4.8-6 Volts, and includes keepers to secure the battery and sensor wire connectors.
RCGF includes a pair of large-volume canister mufflers and gaskets - the mufflers have different offsets, giving them multiple options for mounting. I removed the carburetor and reed block assembly to inspect the reeds - all four laid flat and true against the block. With the reed block removed, I was able to see part of the crankshaft and the lower ends of the connecting rods. The rods have a notch to allow lubrication to the lower end needle bearings.
The Walbro-style pumped carburetor is placed at an angle on the bottom side of the engine allowing straight pushrod travel from the throttle arm to the servo. I like to remove the two end covers from the carburetor to check for any manufacturing debris - neither the pump side nor the screen side had any debris, so the carburetor was reassembled. Nice job RCGF!
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!
I am installing the RCGF 60cc twin in a 27% Ultimate Biplane from The World Models. Once the firewall had been assembled and installed, I marked it according to the instruction manual, and made a mounting template. With the template taped in place, the four mounting holes were drilled in the firewall.
Unfortunately, due to the thickness of the firewall, the mounting bolts supplied with the engine were too short. A quick run to the local home improvement store had new hardware in my hands. For this installation, I used four 10-24 x 1 1/2" stainless steel bolts, blind nuts, and locking nuts. I also added a 5/32" x 7/8" washer between the standoff and the firewall. This was to help prevent the standoffs from sinking into the firewall as the mounting bolts were tightened.
With the engine securely attached (and using a thread locking compound on all nuts and bolts - I prefer Z-42 Blue thread locker available from ZAP Adhesives), I fabricated a throttle pushrod and mounted the throttle servo. The pushrod consisted of three DuBro parts - a pair of 2-56 swivel ball link, a 12" 2-56 pushrod, and a 1/16" threaded coupler. The pushrod was soldered to the threaded coupler, and a swivel ball link was installed on each end. This setup allowed for free movement of the throttle and servo arms, and had no free play.
The fuel tank was assembled using Tygon gasoline tubing and installed, followed by attching the ignition module to the engine mounting box. Three zip-ties held the module in place, with a piece of DuBro 1/4" protective foam rubber between the module and the mounting box. Lastly, the spark plugs were installed, plug wires were attached, and the Falcon 23x8 propeller was bolted to the prop hub. The engine was now ready for break-in!
Falcon 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!
According to the manual, RCGF recommends breaking in the engine by running it at a rich needle setting for 20 minutes at 2,500 RPM. I filled the 650cc fuel tank on the 27% Ultimate, closed the choke and set the throttle to a high idle. I tried hand flipping the engine a few times, but saw no fuel going to the engine - this was not a surprise, due to the carburetor being completely dry. I opened the choke, squirted a little fuel into the throat of the carb, and closed the choke again. With two more flips of the propeller, the engine momentarily started. That was enough to get fuel drawn up to the carburetor! A few more flips had the engine started and running nicely!
Using the trim button on my transmitter, I set the throttle to keep the engine running at around 2,500 RPM. At this speed, it took 25 minutes to run through the first tank of fuel! I let the engine cool off for about 20 minutes (outside air temperature was 82° F) before filling the tank and running it again. Another 25 minutes ticked by and the tank was once again empty. With 50 minutes of run time, I felt more than comfortable to install the cowl and start flying the Ultimate!
Due to a busy schedule, a week had slipped by before I was able to get the Ultimate/RCGF 60 to the flying field. To my pleasant surprise, the fuel line was still full! I filled the 650cc tank, closed the choke, and switched the receiver and ignition switched to 'on'. Six brisk flips of the propeller and the engine coughed. I opened the choke and advanced the throttle two clicks on the left stick, and started flipping the prop once more. Four flips and the engine came to life!
As I do with all of my gas engines, I let the RCGF warm up for a couple of minutes at a high idle. With the engine warmed, I slowly advanced the throttle to wide open, and the 60cc twin responded. "WOW", I thought, "This thing is pulling like a mule!" The combination of the 23x8 Falcon propeller and the 60cc twin was amazing!
The tail restraints were removed, and I taxied the 27% Ultimate out to the grass runway at The Willmar Area RC Club's flying field. We have a fabric runway as well, but it's too short for a plane as large as the Ultimate.
I advanced the throttle once more, and the Ultimate rolled across the grass and took off - I had only reached about two-thirds throttle when the Ultimate broke contact with the ground! Normally, a maiden flight with a new engine can be a hair-raising event. But, having run the RCGF 60cc twin on the ground for more than double the recommended break-in time, I had no doubt in my mind that the engine was going to stay running!
After trimming the Ultimate for straight and level flight, I found that the 60cc twin could easily pull the 15 pound biplane at a scale cruising speed at half throttle. That meant two things: I could get reasonably long flight times, and there was PLENTY of extra power for aerobatics!
I put the 27% Ultimate and 60cc twin though about 15 minutes of flight testing before bringing the plane back to the ground. As I made my last turn to the runway, the engine had settled into a nice idle. I had to 'blip' the throttle a few times to keep the large biplane's speed up for landing, and the engine responded without hesitation every time!
I taxied the plane back into the pit area and shut the engine down by switching off the ignition. The maiden flight for both the 27% Ultimate and the RCGF 60cc twin had been completed without any issues! To say the least, I was grinning widely!
I'm very pleased with the RCGF 60cc twin! The engine looks great, installed easily, and ran very well! The carburetor transitioned nicely between low and high speeds without any hesitation or sputtering, and even the initial starting was easy. RCGF definitely has a great engine in their 60cc twin - and I'm more than happy to have this one residing in my hangar!
No 166-167,Renmin North Road
Email: firstname.lastname@example.org www.zjrcgf.com
Distributed through AirBorne Models
4749 - K Bennett Drive
Livermore, CA 94551
(925) 371-0922 www.airborne-models.com
Distributed by: Frank Tiano Enterprises
3607 Ventura Drive E.
Lakeland, Florida 33811
(863) 607-6611 www.franktiano.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.