Barnard Microsystems Limited

Developing Unmanned Aircraft Systems to benefit Mankind

Four stroke engines running on gasoline - 4 Stroke  Gasoline

InView engine

Above: one of the two SAITO FG-30 four stroke gasoline powered engines on the InView unmanned aircraft.

Four cylinder engines are the most fuel efficient internal combustion engines. They however have lower vibration and noise levels than the two stroke engines, but have a higher vibration level than a Wankel engine. They also have a lower power-to-weight ratio than a two stroke engine of comparable power output.

SAITO 14 cc, four stroke, petrol (gasoline) engine

4 Stroke gasoline powered engine

- from http://www.sussex-model-centre.co.uk/shopexd.asp?id=24406

Development of the Saito FG series of petrol engines continues apace. The latest addition is the new FG14/82. The last two digits refer to its .82 cu.in. capacity. Performance wise the FG-14 is comparable to the FA-72 glow engine. As with other FG engines, it employs a carburettor with a diaphragm pump. This helps make the engine non-critical in terms of fuel levels, allowing the fuel tank to be mounted in a wider range of locations, as well as sustaining fuel flow during aggressive aerobatics and vertical manoeuvres. Each engine is supplied with a sparkplug, muffler and an electronic ignition system. Due to the fuel efficiency of this engine it only requires a tank with one-third the capacity of a similar glow engine. Fuel consumption is rated at 8 cc per minute. The FG-14 runs with any good quality forecourt petrol, mixed 20:1 with oil. Not only does this keep running costs low, it helps keep your airframe clean too as there is minimal exhaust residue.

4 Stroke gasoline powered engine

Specifications:

  • Bore: 29 mm
  • Stroke: 20.4 mm
  • Volume: 13.47 cc
  • Rotational Speed: 1,900 - 9,500 rpm
  • Fuel consumption: 8 cc per minute
  • Propeller: 13 x 8 - 14 x 6
  • Weight: 528g
  • Muffler: 57g included
  • Engine Mount: 124g included

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SAITO 20 cc, four stroke, petrol (gasoline) engine

4 Stroke gasoline powered engine

- from http://www.sussex-model-centre.co.uk/shopexd.asp?id=27741

This 20cc power house brings petrol power to a wide range of medium size models and will be especially welcome in 120 size scale and freestyle aerobatic aeroplanes. Using forecourt quality petrol, mixed 20/30:1 with oil, it is very tolerant of a wide range of fuel levels, so you can fit the fuel tank (just one third capacity of the equivalent glow version) in the best possible position to suit your model's Centre of Gravity. This is made possible by the use of an efficient carburettor fitted with a diaphragm pump.

Besides low running costs and economical fuel consumption at 10cc per minute, the FG-20 is also a very clean running engine and will not foul the airframe with lots of exhaust residues. The power output of the Saito FG-20 is comparable to that of a standard Saito FA-125a glow engine.

Specifications:

  • Bore: 31.7 mm
  • Stroke: 26 mm
  • Volume: 20.52 cc
  • Rotational Speed: 1,800 - 9,500 rpm
  • Fuel consumption: 10 cc per minute at approx 9,000 rpm
  • Fuel GASOLINE : OIL = 20 : 1 ratio, using qulaity synthetic oil
  • Electronic ignition current draw = 780 mA
  • Propeller: 14" x 8" - 10", 15" x 6" - 8", 16" x 6"
  • Static thrust with APC 14" x 8" prop = 3.7 kg
  • Static thrust with APC 14" x 10" prop = 3.5 kg
  • Static thrust with APC 15" x 6" prop = 4.36 kg
  • Static thrust with APC 15" x 8" prop = 4.0 kg
  • Static thrust with APC 16" x 6" prop = 4.7 kg
  • Weight (main body): 690 g
  • Weight (muffler): 83 g
  • Weight (ignition unit): 150 g

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SAITO 30 cc, four stroke, petrol (gasoline) engine

4 Stroke gasoline powered engine - from http://www.sussex-model-centre.co.uk/shopexd.asp?id=30457

With the new FG-30, Saito continue to expand their successful range of petrol engines based upon the most popular sizes of four stroke glow engines. The FG-30 is based on the FA-180 and offers a similar level of performance but at much reduced fuel cost. Each engine comes ready mounted to a matching engine mount to help draw maximum heat from the engine when cowled. The FG-30 is fitted with a Walbro carburetor and is supplied with a Saito electronic ignition system and an efficient muffler.

Specifications:

  • Type: 4-Stroke
  • Displacement: 29.11 cc
  • Bore: 36.0 mm
  • Stroke: 28.6 mm
  • Cylinders: Single - Chrome Plated
  • Crankshaft Threads: M8 x 1.25 mm
  • Benchmark Prop: 16x8 APC @ 9,300
  • Prop: 16" x 8", 16" x 10", 17" x 6", 17" x 8"
  • RPM Range: 1,700 – 9,000 rpm
  • Static thrust with APC 16" x 8" prop is 5.0 kg
  • Static thrust with APC 16" x 10" prop is 5.3 kg
  • Static thrust with APC 17" x 6" prop is 5.8 kg
  • Static thrust with APC 17" x 8" prop is 5.3 kg
  • Electronic ignition electrical current draw is 790 mA
  • Fuel consumption 25cc / min at approx 8,500 rpm
  • Fuel GASOLINE : OIL = 20 : 1 to 30 : 1 (20 : 1 is standard) using high quality synthetic oil
  • Mounting Dimensions: 138 mm x 69 mm x 135 mm
  • Muffler Type: Cast
  • Cylinder Type: AAC
  • Carb Type: Barrel, 2-needle valve
  • Crank Type: Ball bearing
  • Weight (engine only): 1,055 g
  • Weight (muffler): 85 g
  • Weight (mount): 190 g
  • Weight (ignition system): 158 g

Support:

Before you run your Saito petrol four stoke engine for the first time please lubricate the engine through the back plate breather nipple with a small amount of light machine oil or two stroke oil that you are going to mix into your fuel. This will help to lubricate the moving parts of the engine until the fuel/oil mix is able to reach these parts during the engines first run.

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SAITO 36 cc, four stroke, petrol (gasoline) engine

4 Stroke gasoline powered engine

- from http://www.sussex-model-centre.co.uk/shopexd.asp?id=24406

The Saito FG-36 is supplied with a CE approved electronic ignition system and a purpose made aluminium engine mount. The carburettor employs a diaphragm pump for reliable fuel feed in any attitude - even the wildest of 3D stunts! This also means that it is not sensitive to the position of the fuel tank, which allows the tank to be positioned to maximise the CG position. You can use forecourt quality petrol mixed in a ratio of 20:1 to 30:1 petrol to oil. The FG-36 is very clean running and is very economical.

 

Key Features:

  • 4-stroke petrol engine from one of RC's top brands
  • 36 cc displacement rivals similarly sized 2 strokes
  • Includes: Ignition, Muffler, Walbro Carburettor and Motor Mount
  • Built for the utmost in reliability and performance
  • Brings Saito experience to gas enthusiasts
  • Comparable in power to Saito FA-220 glow 4-stroke
  • Available in traditional silver case

Specifications:

  • Type: 4 stroke gasoline engine
  • Displacement: 36 cc
  • Bore: 35 mm
  • Stroke: 32 mm
  • Cylinders: Single
  • Total weight: 1,760 g for Motor + Mount + Muffler + Ignition
  • Engine only weight: 1,252 g
  • Muffler weight: 86 g
  • Crankshaft threads: 8 x 1.25mm (step up is 10mm)
  • Benchmark prop: APC 18 x 6W @ 8,300 rpm
  • Prop range: 18"-19" x 8"-9”, 20" x 8" (Bolly or Mejzlik)
  • RPM range: 1,700 - 9,000 rpm
  • Fuel: gas oil mix of 20:1 to 30: 1 (20:1 for break in)
  • Mounting dimensions: 124 mm x 85 mm x 173 mm
  • Muffler type: Cast
  • Power: 2.6 kWatts
  • Cylinder type: Ringed
  • Starting system: Saito Ignition 4.8v - 6v (capacity more than 1,000mAH)
  • Carburettor type: Walbro/Saito
  • Crank type: Ball Bearing

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The new SAITO 57 cc, twin cylinder, four stroke, gasoline (petrol) engine

4 Stroke gasoline powered engine

- from http://www.horizonhobby.com/Products/Default.aspx?ProdID=SAIEG57T#quickOverview

Key Features

  • Gasoline version of the well-known FA-300T Glow engine
  • Broader torque curve with gasoline fuel applications
  • Phenomenal 4-stroke sound in a gasoline package
  • Complete with electronic ignition, mount and mufflers

Overview

Saito is proud to introduce their first twin cylinder gas engine – The FG-57 Twin Gas Engine. The FG-57T is designed for larger models, specifically scale applications where the sound of the engine is a key factor in the flying experience. The FG-57T is the only twin cylinder 4-stroke engine on the market that is fueled by gasoline. As a result, the benefits are easier tuning and operating costs savings of up to 90% over similar glow power systems. Decreased operating costs of up to 90% over nitro engine performance based on fuel consumption and price per gallon.

By combining the reliability of gas with the sweet sound of Saito, advanced technology and foresight are once again helping Saito lead the way into the future. And, like all Saito engines, these powerhouses are engineered with that same Saito quality and reliability our customers have come to know and trust.

  • Type: 4 stroke gasoline engine
  • Displacement: 57 cc
  • Bore: 36 mm x 2
  • Stroke: 28 mm
  • Cylinders: Twin
  • Total weight: 2,500 g for Motor + Mount + Muffler + Ignition
  • Engine only weight: 2,200 g
  • Muffler weight: 119 g
  • Crankshaft threads: 10 mm
  • Benchmark prop: Mehzlik 23 x 8 @ 5,900 rpm
  • Prop range: 22"- 23" diameter x 8"- 9” pitch (Bolly or Mejzlik)
  • RPM range: 1,200 - 7,000 rpm
  • Fuel: gas oil mix of 20:1 to 30: 1 (20:1 for break in)
  • Starting system: Saito Ignition 4.8v - 6v (capacity more than 1,000mAH)
  • Carburettor type: Walbro
  • Crank type: Ball Bearing
Kavan

KAVAN 50cc Four Cycle Twin Engine

The Kavan engine: photograph from www.mecoa.com

  • Engine capacity = 50 cc
  • weight = 2.6 kg for spark ignition version
  • power output at 9,200 rpm = 3.28 kWatts , where the fuel consumption was 25 cc per minute.
  • power-to-weight ratio = 1.261 kW / kg
  • fuel efficiency = 0.856 Joules / cc_fuel_air_mixture

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The Rotax 914 by Bombardier Rotax

4 Stroke gasoline powered engine

- from http://www.rotax.com/en/

Performance of the four stroke, four cylinder, Rotax 914 F D.C.D.I UAV Engine

power

84.5 kW

@ 5,500 rpm

maximum RPM

5,800

rpm

displacement

1211.2

cc

generator performance

250 Watt DC

@ 5,500 rpm

voltage

13.5

V

fuel usage at 5,400 RPM

20 kg/hr (25 L / hr)

237 g / kWatt / hour

AVGAS 100 LL

engine weight

70

kg

weight of optional extras

6.7

kg

power-to-weight ratio

1.1

kW / kg

engine efficiency

1.55

J / ccfam

This large engine is included to give a data point for a high capacity engine. The Rotax engine has been used in the Predator and other UAVs.

4 Stroke gasoline powered engine

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