Lately, there has been a noticeable shift toward smaller displacement single-cylinder, gasoline engines and there are now many of these little gas-burning powerhouses on the market. Years ago, when you talked about gas engines, the smaller end was owned by the 25cc engines and the average size was roughly between 40cc and 60cc with a few exceptions. Gasoline engines have also grown to monstrous sizes in the 150 and 200cc ranges with other multi-cylinders radials sporting 400cc. I guess it’s only natural that smaller engines have come along to try and balance out the size spectrum.
Why use a small, “20cc and under” gasser? Well, there are several advantages. First, there are tons of 40 to 60 size sport planes out there and many of these smaller gas engines will easily slip into place with little effort. Gasoline engines are extremely fuel efficient compared to methanol/nitro powered engines and the cost per gallon for gasoline is also about a quarter as expensive as glow fuel. If that’s not enough, Walbro-type pumper carburetors are very easy to adjust and maintain. And, with their electronic ignitions, gasoline engines are also very easy to start.
So what’s not to like? Exactly! Here are some of the more popular “20cc and Under” gas powerhouses available today.
Hobbico/ O.S. GT15 Gasoline Engine
Featuring an IG-06 electronic ignition system compatible with 4-6 cell NiCd, NiMH or 2-cell LiPo and LiFe batteries, Beam style engine mounts, the GT15 Gasoline Engine is designed to fit cowls that are sized for 2-stroke .60-.91 and 4-stroke .90 glow engines The engine includes: E4040 Muffler, IG-06 Ignition Module, CM6 Spark Plug, 61H Carburetor, and Instruction Manual. Propeller range: 13×8-11, 14×8-10, 15×8
Displacement: 0.912 cu in
Bore: 1.091 in
Stroke: 0.976 in
Practical RPM: 2,000 – 11,000 RPM
Weight: 22.26oz (631g) engine
6.28oz (178g) muffler
3.35oz (95g) ignition module
Gasoline/Oil Mixture: 30:1 – 50:1 (25:1 recommended)
Plug Type: CM6
O.S. GT22 Gasoline Engine
Featuring a sturdy Beam mounting design the O.S. GT22 fits inside cowls sized for 2-stroke .60-.91 and 4-stroke 1.20 glow engines. It features a custom designed rear mounted Walbro carburetor with choke rod guide integrated into crankcase that minimizes set-up time. Also includes are IG-02 electronic ignition, (for 4-6 cell NiCd, NiMH or 2-cell LiPo and LiFe batteries,) a Pitts style muffler with reinforced mounting bolt holes and webbing at high stress points. Propeller range : 16×8, 16×10, 17×6, 17×8, 15×10 for break-in.
Displacement: 1.35 cu in
Practical RPM Range: 1,800 – 9,000
Output: 2.66 hp @ 9,000 RPM
Engine weight: 26.86oz., Muffler: 4.68oz., Ignition Module: 3.7oz.
Horizon Hobby Evolution 10GX
Based on the proven 60NX glow engine, the Evolution 10GX is one of the smallest gas 2-stroke engines available. It fits into most traditional .46 – .60 mounting spaces with no special installation necessary. Uses a 5% oil mixture with gasoline and its 4.8–8.4V ignition case is half the size of traditional electronic ignition systems. The engine features a new carburetor system features a crankcase-pressure driven regulator system and a new cat’s eye style fuel metering system for improved low and mid-range performance. Supplied muffler spark plug, ignition system and gasoline-grade fuel tubing and filters
Displacement: 0.59 cu. in.
Bore x Stroke: 0.94 in. 0.85 in.
Weight: 22.0 oz
RPM Range: 2,300 – 18,000
Rec’d Prop: 12×6
Prop Range: 10×6 – 13×8
Crankshaft Threads: 1/4-28
Plug Type: 1/4-32
The pilots of larger airplanes the 15GX offers the same great features of the 10GX in a larger engine for the .61- to .91 airplanes. Key Features include lightweight construction based on the Evolution91NX glow engine, outstanding power and performance, a 2S Li-Po battery compatible ignition without a voltage regulator for long run times, lightweight electronic ignition system and a reliable, easy-to-tune and efficient fuel system. It’s standard beam mount makes installation effortless. Includes: muffler and muffler screws and gasket, spark plug, Evolution/Spektrum telemetry RPM adapter cable, medium gas- fuel tubing, in-line fuel filter, in-tank felt filter/clunk.
Bore x Stroke: 1.09 in x 0.98 in.
Weight: 31.1 oz
RPM Range: 1,600-13,000 rpm
Rec’d prop: 14×6
Prop Range: 13×7 to 15×6
Crankshaft Threads: 5/16-24
Spark Plug: 1/4-32
Based on the Evolution 1.20NX glow engine, the 20GX 20cc is a small block gasoline engine designed for .90- to 1.20-size airplanes. It’s has a standard beam mount and compact dimensions so it will fit anywhere you would use a .91- to 1.20 glow engine. It’s also remarkably lightweight, even with the ignition system and battery. With the included 2S Li-Po ready electronic ignition and muffler pressure-regulated type carburetor, easy starts and tuning are a breeze. An in-cowl muffler is included as well as fuel tubing and filters that can handle gasoline.
Bore x Stroke: 1.20 in x 1.10 in
Weight: 33.6 oz (958 g)
RPM Range: 1,800-10,000
Rec’d Prop: 16×6
Prop Range: 15×6 to 17×8
Crankshaft Threads: 5/16-24
Plug Type: 1/4-32
Price: $ 279.99
Saito FG-17 (100) 4-Stroke
The popular Saito brand is continuing to expand its line of gasoline engine with the addition of the FG-17cc 4-stroke engine. The FG-17cc is a low operating-cost version of the tried and true Saito FA-100 glow 4-stroke, with the same performance. This new engine uses the latest Saito “pump carb” technology, inset valve seats as well as a new ignition system. The FG-17cc engine is ideal for any .60 size model or any model currently using the FA-100. Like all Saito engines, these powerhouses are engineered with that same Saito quality and reliability you’ve come to know.
Bore x Stroke: 1.14in. x 1.02in.
Weight: 27.2 oz.
RPM Range: 2,000 – 9,500
Rec’d Prop: 15×6
Prop Range: 14 x 8 – 16 x 6
Carburetor: 2-needle Saito Gas Carb
Crankshaft Threads: 8 x 1.25mm
Spark Plug: 1/4-32, 4-Stroke
Saito FG-14C (82B) 4-Stroke
The smallest gasoline-powered 4-stroke engine on the market, the Saito FG-14C is the gas equivalent of the 82 AAC glow engine in terms of size and dimensions, yet it gives you the cleaner, lower-operating cost of gas with 14cc of power. Above and beyond the advantages of a 4-stroke gas engine, this is the engine for those who like to run clean and efficient engines. The engine comes with the Saito 4-stroke ignition module, Saito pump carburetor, muffler and engine mount.
Bore x Stroke: 1.14 in. x 0.80 in.
Weight: 25.8oz. (with ignition)
RPM Range: 2,000–9,300
Recommended Prop: 14 x 6
Prop Range: 13×8–14×8
Carb Type: 2-needle Saito pump-type
Crankshaft Threads: M7 x 1mm
Zenoah ZP 20cc
Known for their legendary reliability, the Zenoah engine line offers power to spare. Now outfitted with the ZP electronic ignition system, the ZP20 share many of the core components used in the magneto powered Zenoah G20. The ignition system can be powered with everything from a 4.8V NiCd or NiMH pack to a 7.4V 2S LiPo pack. No power regulators are required and the current draw only 450mAh so you’ll be able to use smaller capacity battery packs to save weight. Key Features are aluminum carburetor arms for choke and throttle, Custom-machined grey-anodized prop drive, Lightweight muffler and spark plug included.
Benchmark Prop: APC 16 x 6 @ 9000 rpm
Bore x Stroke: 1.26 in. 0.98 in.
Weight: 41.6 oz. (with muffler, ignition and mount)
RPM Range: 1,400–10,000
HP: 2.1 hp @ 9000 rpm
Prop Range: 15×8 – 16×8
Carb Type: Walbro
Crankshaft Threads: 8 x 1.25mm
Hobbico/ DLE Engines DLE-20cc
This popular gasoline engine features two sealed crankshaft bearings, aluminum alloy crankcase with advanced CNC machining, a rear-mounted pumper carburetor, a fully automatic electronic ignition and a 2-year limited warranty. It features easy beam mounting to fit in the same engine mount as a comparable glow engines. Engine comes with: spark plug, ignition, muffler, muffler gasket, two 5x20mm muffler bolts and instruction manual.
Displacement: 20cc (1.22ci)
Bore x Stroke: 1.3 x 1.0 in.
Power: 2.5 HP
RPM Range: 1,900 – 9,000
Spark Plug: CM6
Carburetor: Rear-mounted pumper
Propellers: 14×10, 15×8, 16×6, 16×8, 17.6, 18×6
Valley View RC/ VVRC 20cc
Developed specially for Valley View RC, the VVRC 20cc has engine is one of the best engines on the market today. Valley View RC has ran several of these engines on their test stand and in the air powering several RC airplanes with no failures. The VVRC 20cc engine comes with a Rcexl ignition, NGK-CM-6 spark plug, a composite engine mount and long throttle and choke arms.
RPM Range: 1,650 – 9,000
Output: 2.5 hp @ 9,000RPM
Propellers: 14×10, 15×8, 16×6, 16×8, 17×6, 17×8
Hobby King/ RCG 20cc
With its easy starting characteristics and reliable low-maintenance running the RCG 20cc is an excellent engine. RCG engines have proven themselves the world over for quality and reliability.
Bore/Stroke: 32mm x 25mm
Prop Speed: 1,500 – 9,800rpm
Max power: 2.2hp
Ignition: DC-CDI (Electronic)
Power Supply: 4.8-6v
BP Hobbies/ CGF 20CC Version 3 (Rear – B Crank Case)
These powerful gas engines are known worldwide for their high quality, power and customer support. All engines come with prop adapter, muffler, motor standoff, spark plug, electronic CDI ignition and one year manufacturer’s warranty. (Beam Mount Version also available.)
Displacement 20 cc
Bore x Stroke 1.25 x 1.02″
Ignition DC-CDI (Electronic)
Power Supply 4.8 – 6.0 V
Weight: 32.8 oz
Max Output 2.6 hp
Speed Range 1,500 – 9,800 rpm
Propeller(s) 15×6, 16×6
Bolt Size M4 – 4mm
RCGF / 15CC Version 2
Made by Zhejiang RCGF Model and Engine Co. These powerful gas engines are known worldwide for their high quality, power and customer support. All engines come with prop adapter, muffler, motor standoff, spark plug, electronic CDI ignition and one year manufacturer’s warranty. (Beam Mount Version also available.)
Displacement 15 cc
Bore x Stroke 1.14 x 1.02 in.
Ignition DC-DCI (Electronic)
Power Supply 4.8 – 6.0 V
Weight: 29.1 oz
Max Output 2.1 hp
Speed Range 1,500 – 15,000 rpm
Propellers: 13 x 8 – 15 x 8
Prop Bolt Size M4 – 4mm
Today it’s getting more and more difficult to find gasoline that does not contain some alcohol. While it will take some time and a lot of gas run through your engine before it will eventually affect performance, alcohol attracts water and moisture causes corrosion. It’s now advisable to run your gas engine and fuel tank dry of fuel at the end of the day and use some after run oil. Marvel Mystery Oil is an excellent choice for after run treatments. Also, if your engine begins to become more difficult to start, check your inline fuel filter and your carburetor’s internal fuel filter screen. If they show signs of becoming clogged, replace them with new ones. Walbro internal screens are available at most small engine repair shops.
Gasoline engines have always been the heartthrob of the giant scale set and they offer great performance and reliability. Adding their user-friendly traits and miserly fuel consumption to smaller airplanes is a great way to increase your RC hobby fun factor. Make the switch to gas and your .40 to .60 size sport plane and see the difference it makes!
7 Easy Steps for Starting Electronic Ignition Engines
For safety reasons we always recommend the use of an electric starter, but if you want to hand prop your engine to life, here’s the best way to do it.
1. Make sure your flying buddy holds yours model so it can’t move forward.
2. Position the propeller relative to the engine’s compression stroke according to the instructions. Make sure the prop nut or bolts are properly tightened.
3. Turn the ignition kill switch off, and close the choke. To draw fuel into the carburetor, flip the prop until you see gas flowing through the fuel line and into the carburetor.
4. Open the throttle fully, turn on the ignition system but keep the choke closed.
5. Flip the prop again until you hear the engine “cough” indicating that your engine is properly primed. 6. Now, close the throttle, advance the throttle trim fully and open the choke.
7. Flip the propeller again and the engine should start. If not, switch the ignition off, and repeat the procedure.
For most gas engines, a fuel mixture of between 30:1 and 50:1 will work while providing sufficient lubrication of its internal parts. If you are unsure which ratio to use, refer to the engine operation manual or check with the manufacturer. Here’s some popular ratios recommended by engine manufacturers.
100:1 1.28 (Recommended only for synthetic oils)