Small-Block RC Gas Engine Guide — A New Generation of compact Power!

May 14, 2014 22 Comments by

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

OSGT15

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

Price: $349.98

 

O.S. GT22 Gasoline Engine

OSGT22

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

Bore: 1.26″

Stroke: 1.08″

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.

Price: $389.97

 

Horizon Hobby Evolution 10GX

EVOE10GX

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.

HP:                         1.68hp

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

Price:                     $199.99

 

 

Evolution 15GX

EVOE15GX

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.

Specifications

Displacement:   0.91ci.

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

Price:                     $249.99

Evolution 20GX

EVOE20GX

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.

Specifications

Displacement:   1.20ci.

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

SAIEG17

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.

Displacement:       1.05ci.

Type:                        4-stroke

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

Price:                        $449.99

 

Saito FG-14C (82B) 4-Stroke

Saito14

 

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.

Displacement:                        .82ci.

Type:                                        4-stroke

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

Price: $399.99

 

Zenoah ZP 20cc

ZENEP20

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

Displacement:        1.22ci.

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

$299.99

 

Hobbico/ DLE Engines DLE-20cc

DLE20

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.

Specifications

Displacement:   20cc (1.22ci)

Bore x Stroke:   1.3 x 1.0 in.

Weight:                28.9oz

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

Price:                     $249.99

 

Valley View RC/ VVRC 20cc

VVRC

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.

Displacement: 20cc

Bore:                  1.3in

Stroke:               1.0in

Weight:              26.5oz

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

Price:                  $189.95

 

Hobby King/ RCG 20cc

RCGF20

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.

Specifications

Displacement:   20cc

Bore/Stroke:      32mm x 25mm

Weight:                1,000g

Carburetor:        Walbro

Prop Speed:       1,500 – 9,800rpm

Max power:       2.2hp

Propeller:            15×6

Ignition:               DC-CDI (Electronic)

Power Supply:   4.8-6v

Price:                    $159.99

 

BP Hobbies/ CGF 20CC Version 3 (Rear – B Crank Case)

RCGF15

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″

Carburetor          Walbro

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

Price:                    $235.95

 

RCGF / 15CC Version 2

RCGF15a

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.

Carburetor         Walbro

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

Price:                     $202.95

 

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.

sb. alcohol-free VPRacing

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!

sb.engine hand start

 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.

Fuel Mixes

oil

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.

Ratio                      Oz./Gal.

100:1                     1.28 (Recommended only for synthetic oils)

64:1                        2

50:1                        2.5

40:1                        3.2

32:1                        4

Featured News, From the Magazine, Gerry Yarrish

About the author

Senior Technical Editor About Me: I have a lifelong passion for all things scale, and I love to design, build and fly scale RC airplanes. With 20 plus years as part of the Air Age family of magazines, I love producing Model Airplane News and Electric Flight.

22 Responses to “Small-Block RC Gas Engine Guide — A New Generation of compact Power!”

  1. Michael Massey says:

    Now if ARF manufactures would produce planes that are designed specifically for these small engines and their ignition systems. There are only a few models out there.

  2. jeb says:

    I have a RCGF 15cc that runs flawlessly. I’m looking for a new aircraft for it. It seems that since the power is equivalent of at least a .60 nitro engine, there should be a lot of choices of aircraft but not so. It seems there a lot of .40 powered craft out there. There don’t seem to be many designed for a .60. The engine is pretty big and heavy for a .40 powered airplane.

  3. Chad says:

    I have started switching from nitro to gas engines and my only question is: with ethanol in the gas will it hurt to use Aviation gas even though it is about 100-103% octane. I believe there is no ethenol in it.

    • Gerry Yarrish says:

      I have heard of modelers using Av-gas with little or no problems. Also, Coleman stove fuel “White Gas” can also be used, and has no ethanol. It is getting harder to find gas stations without some percentage of ethanol added.
      Gerry

      • Marc says:

        Keep in mind 100LL avgas has a very large amount of lead, (4 times the amount per gallon that the old leaded mogas) 100LL has 2mg of tetraethyl lead vs. .5mg per gallon of the old leaded car gas. Coleman fuel is about 65 octane. Mix the 100LL and Coleman 50/50 and you should be fine.

    • Nick says:

      I have an app on my iPhone called Pure Gas that shows me all the stations in my area that have ethanol-free gasoline. I NEVER put ethanol in ANY of my small engines since I screwed up an outboard boat engine with FOUR carbs on it!!

  4. DaveZ says:

    I came back into the hobby after almost a 20 year break and picked up an 800 class gas helicopter. I love it. Super easy to start, runs an easy 45 minutes to spare. The best part, all I need is the helicopter, my transmitter and a jug of gas.

  5. David says:

    I’ve been told that these motors are much noisier that equivalent glo motors. Is this the general rule?

    • Rob says:

      Where are the O.S. GT15 and GT22 gas engines? Big omission IMO.

      • Gerry Yarrish says:

        Thanks for your comment Rob. This article was published a while ago, so did not have the new O.S. engines included. When I get a chance I will add the engines to the roundup!
        thanks for writing!
        Gerry

    • Gerry Yarrish says:

      The noise an engine makes really depends on the type and quality of the muffler used. Some of the included stock mufflers might not be as efficient as aftermarket ones but in general, they are in the same range as Glow engines. Also with RPM being a factor, Gas engines do their work best at lower RPM ranges so here it will be making less high frequency noise. Hope this helps
      Gerry

    • Skipper D. says:

      I have had noise level tests run on my gas engines at events, and they were somewhat quieter than most nitro engines. They normally run larger props at lower rpms, and have a deeper sound which gives a perception also of being quieter and more pleasant. Of course in the long run, it depends on the muffler and how the engine is propped, and the type of airframe which can contribute to the overall sound. You can’t compare their noise to “chainsaws” or “weedeaters” which operate at considerably higher rpms.

  6. Paul Ouellette says:

    The gasoline engines in this size range are not any louder than it’s equivelant nitro burning engine. The reliability, ease of use, cost to run, and the fact they are MUCH cleaner (not near the oil residue) make these the only way to go!! I’ve been using gas engines for years now (30cc to 120cc) and they are by far the best way to power your model… unless you’re an electric fan.

  7. Humberto pachon says:

    will be that some of these engines work for
    600 or 700 size helicopters

  8. Pete says:

    Question: Currently we do not allow gas engines at our fielsd because of noise issues. How do these new smaller engines compare to comparable nitro engines from a noise standpoint?

  9. BrianBeer says:

    For you gas burners out there, I heard that Shell 92 octane has no ethanol in it. I recall reading this in RCU while surfing the site.

    • Skipper D. says:

      In all cases, read the label on the pump, but consider this. The hose on most of today’s pumps from the switching valve to the nozzle is full of what the last customer bought. Now this may not make a lot of difference if you are filling up your car, but if you are just getting a gallon for your models, think of the quantity that long big hose has in it. Hmmmmm.

      • Jim Cox says:

        Before filling your gas can, put the first couple of gallons into your vehicle, this should clear the gas pump hose of any residual gas with ethanol in it.

  10. Gerry Yarrish says:

    I suspect the amount of noise any engine produces is a factor of its muffler. Since gas engines run at lower rpms that glow, I think in general they do not make more noise. IMO.

  11. Chris says:

    I know over here in Canada we are allowed to have up to 10% by volume of Ethanol in the gas. I am not a 100% sure on the high grades such as Ultra94 or Super. I don’t “think” they do. Anyone know of a test that can be preformed? Without needing a degree in chemistry?

    • Sam Rumade says:

      Simple to check.use measuring cup,put water in to first measuring line. Fill cup with fuel.if the water line rises fuel has alcohol in it. Alcohol is clear and is attracted to water. Sometimes additive in the fuel will make a milky line separating fuel and alcohol ,water mix. Hope this helps.

  12. Ray Richter says:

    I wish when people show oil to fuel ratio’s they would indicate if the measurement is in U.S. Oz./Gal. or imperial/U.K. Oz./Gal. I hate having to convert all the time or have to find out where the info came from. This is an international web site. Maybe the best solution would be for the U.S. to catch up to the rest of the world and adapt to metric. ml:L or show both U.S. & metric or U.K. & metric.

    Ray

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