Ephil EP 40cc Twin Pro Gas Engine With Autostart

A dependable and economical gas engine

By Fitz Walker | [email protected]

Photos by the author

The EPHIL 40cc REVIEW Twin Pro engine has enough grunt to pull the Shock Cub through its paces.

The ESC is mounted inside of the Shock Cub’s cockpit. Note the optional tachometer display on the right.

I’LL ADMIT THAT, for as long as I’ve been in this hobby, I’m actually relatively new to flying gas-powered models. After decades of tinkering with glow engines and electric motors, moving to gasoline power has been both a familiar path and a new learning experience.

Cheap fuel and big airplanes have been a great advantage of gasoline power; however, one thing that always gives me a bit of trepidation is hand-starting these large engines that have nearly 2-foot propellers. Even with an electric starter, just holding the model while cranking up makes me slightly paranoid.

Enter the EPHIL EP 40cc Twin Pro Twin-Cylinder Engine With Autostart from Valley View RC. This is an opposed-cylinder twin-engine with an electronic ignition and hands-free electric starting.

The engine is rated for 4.6 hp with the propeller ranging from 19 × 8 to 21 × 8 inches. The basic engine core weighs 2 pounds, 13 ounces. With all of the accessories needed for flight (ignition module, mufflers, starter controller, etc.), the total weight is 3 pounds, 12 ounces.

It is somewhat unusual for an engine this small to have an autostart feature, so my curiosity upon unboxing the engine went immediately to the starting mechanism. There is a surprisingly small brushless motor with multistage gearing connected to a large reduction gear on the engine’s output shaft.

The reduction gear is part of a one-way bearing so that the starter motor will not spin after the engine is started. An attractive, transparent cover over the motor gears helps keep the dirt out.

The engine itself is a finely cast body with stylish cooling fins. Spark plugs (1/4-32 threads) are angled downward at roughly 45°. The entire unit looked easy to disassemble with logically placed bolts holding all of the parts together. The carburetor is an industry-standard Walbro with choke control and high-and low-end mixture adjustments.

At a Glance

Specifications

Displacement: 40cc (2.44 cu. in.)

Performance: 4.6 hp

Speed range: 1,800 to 8,300 rpm

Bore: 32mm (1.26 inch)

Stroke: 27mm (1.06 inch)

Static thrust: 11.5 kg at 100 meters altitude (25.4 pounds at 328 feet altitude)

Static thrust: 9 kg at 1,800 meters altitude (19.8 pounds at 5,900 feet altitude)

Compression ratio: 9:1

Lubrication ratio: 40:1 (fuel: two-stroke synthetic oil)

Ignition voltage: 6 to 14 volts

Spark plug type: 1/4-32 (ME-8)

Recommended propeller: 20 × 8; 20 × 10; 21 × 8

Pluses

• Effortless starting.
• Good power.
• Compact size.

Minuses

• Missing ESC programming information.

Manufacturer/Distributor

Valley View RC

(253) 875-6890

www.valleyviewrc.com

Mufflers are black anodized aluminum with offset exhaust mounts because of the slightly staggered opposed-cylinder heads. Each muffler has a removable screw on its end for those who want to add a smoke fluid injector.

The complete package of the EPHIL EP 40cc Twin Pro engine.

The brushless motor offers good starting power in a compact package.

The mufflers have built-in taps for the included smoke injectors.

Screw-in nipples for smoke fluid are conveniently included in the package. I should note that the throttle-stop adjustment screw interfered with one of the mufflers and needed to be removed; otherwise, I wouldn’t have been able to mount the muffler. Fortunately, that screw is not needed for RC models.

You get two pieces of electronics as well. First is the dual sparkplug ignition module (with tachometer output port) rated for 6 to 14 volts. Next is the starter motor controller, which, for all practice purposes, is an ESC, commonly seen in electric-powered airplanes.

This brushless ESC is rated for up to 4S LiPo batteries and has a BEC rated for 3 amps (which I will get to later). A four-bolt propeller mounting pattern matches other engines of the same size class and uses 5mm bolts. With spark plugs and ignition cables installed, I measured the total engine width at 8.5 inches.

After admiring the engine, it was time to find a suitable test bed for it. I had the perfect model in mind, which is the 102-inch wingspan Shock Cub from Legend Hobby. This Seagull Models kit has a wide cowling and is designed for 40cc-size engines. The model is a great-flying, short takeoff and landing airplane and very forgiving in case I have any issues.

The first step was to mount the engine, which matched perfectly with the firewall mounting holes of the previous engine (also a 40cc twin). Even the throttle linkage was nearly a perfect match for length, and the same is true for the length of the engine. I did need to use a new cowling because the muffler exhaust pipes are in a slightly different location from the previous engine.

I bolted on the recommended 20 × 8 break-in propeller and mixed some 30:1 oil and ethanol-free gasoline mix. (You can use a 40:1 mix after the engine is broken in.) My radio transmitter was then programmed to control the starter ESC to a switch on a spare channel. A 4S 2,200 mAh LiPo battery was initially used for motor-starting duty.

I should note that the instructions say to use the voltage regulator built into the ESC. Because the built-in regulator is set at 5.1 volts and is only rated for 3 amps, I didn’t feel comfortable using it. I removed the red wire from the ESC’s servo connector, as now noted in an addendum to the instructions, and used the same 7.4-volt LiPo receiver battery pack already in the model. Disconnecting the red wire prevents the voltage regulator from feeding the receiver. You will also need to install or solder your battery connector of choice to the ESC.

The first attempt at starting the engine had the electric motor spinning backward. Simply swapping two of the three motor wires had it spinning in the right direction. With the choke closed, I pressed the start button and the propeller quickly spooled up to a moderate speed. The engine sputtered after only a couple of seconds of spinning. Stopping the starter after the first pop, the choke was opened and another flick of the starter switch had the engine springing to life with a nice, steady, high idle. It was almost too easy!

Factory-set fuel mixture settings were fine for getting the engine to run consistently. After a couple of tanks of fuel, I richened the low-speed mixture an eighth of a turn in order to get a good low-idle speed. At that point, the speed range was 1,300 to 7,200 rpm on a Falcon 20 × 8 wooden propeller using the break-in fuel.

The next step was to see how it did in the air. Without a spinner, my trusty Shock Cub looked a little different than usual, but I had removed it, because if all went well, I would no longer ever need to use a hand-held starter to crank it up—and crank up it did.

Out at the starting area, after a flip of the starter switch and a couple seconds of being motivated by a 4S 2,200 LiPo battery pack, the engine sprang to life. No helper or tie down was needed to hold the airplane. I think I just might like this.

I tried the system with a smaller 3S LiPo pack and it worked well enough, but 4S has noticeably more power and speed.

Despite the engine being just a touch on the rich side, at full throttle, the Shock Cub leaped into the air as it normally did, never missing a beat as I leveled off the steep climbout. After a few passes, I made a point to cruise around at different throttle settings to listen for any mistunings. Top-, mid-, and low-throttle settings seemed to be well adjusted and consistent.

The Shock Cub is not overly aerobatic and it takes a fairly good powerplant to pull its draggy airframe through the air, but the EPHIL EP 40cc Twin Pro engine pulled as well—or better—than what was in it before. Through loops and sustained steep climbs, the engine chugged along like a champ. Upon landing, everything seemed to be just the same as when it was first fired up, and it held a consistent idle back to the pits.

The idle throttle stop screw will need to be removed to avoid interference with the muffler.

The mounted engine looks classy.

There were a couple of minor nitpicks that I had with the system, the first being that the optional RCEXL Tachometer rpm gauge’s red LED numbers were slightly hard to see in full daylight, which was okay since the rpm readings were far from correct anyway. I might have gotten a defective unit, but I found that odd.

The second thing I noticed was that the starter motor would start freewheeling when the engine was at full throttle. (I’m guessing that the one-way bearing had some slight friction in it.) Additional instructions on how to program the motor brake in the ESC would have been nice. That noted, these were extremely minor, harmless issues.

The EPHIL EP 40cc Twin Pro is a fine engine with great performance and great convenience. It brings self-starting ability to a whole new class of gas-powered airplanes in a classy, twin-cylinder package.

The ability to restart a stalled engine in flight is also an added bonus. The brushless starter motor should last forever with trouble-free operation.

After you have experienced the convenience of self-starting, it’s hard to go back to using your hands like an uncivilized modeler!

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