Barnard Microsystems Limited

Developing Unmanned Aircraft Systems to benefit Mankind

Four stroke engines using methanol - 4 Stroke

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.

Enya engine

4 Stroke engine

ENYA R.155.4C engine from http://www.modelflight.com.au/enya_engines/enya_r155.htm

engine

capacity in cc

power output in kWatts

J/ccfam

120FS

19.93

1.566 at 11,250 rpm

0.838

R.155.4C

25.42

1.86 at 11,250 rpm

0.780

Notes:

  • All Enya engines use " glow fuel" : methanol + 5 to 15 % nitromethane + 16% minimum synthetic castor oil lubricant.
  • J/ccfam = energy in Joules per cc of fuel-air mixture
  • J/ccfam = ( power_in_watts x 60 x 2 ) / (capacity_in_cc x rpm ) = measure of energy efficiency

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O.S. Engines

4 Stroke engine

O.S. Engines FS-70 Ultimate high performance, four stroke, engine with a fuel pump.

Photograph from www.osengines.com

4 Stroke engine

O.S. Engines FT-300 two cylinder engine from www.osengines.com

engine

cylinders

capacity in cc

weight in kg

power output in kWatts

kW / kg

J/ccfam

FS-70 Ultimate

1

11.45

0.502

0.894 at 11,000 rpm

1.781

0.852

FS-91 S II

1

15

0.649

1.193 at 11,000 rpm

1.838

0.868

FS-120S III

1

20

0.921

1.56 at 12,000 rpm

1.694

0.76

FT-160

2

26.5

1.1

1.49 at 10,000 rpm

1.354

0.675

FS-200U

1

32.4

0.83

2.16 at 9,000 rpm

2.605

0.890

FT-300

2

49

1.828

3.0 at 7,000 rpm

1.641

1.050

FF-300 radial

5

49.7

2.673

3.0 at 8,000 rpm

1.122

0.905

FF-320

4

53.2

2.19

3.06 at 8,000 rpm

1.37

0.846

Notes:

  • All O.S. engines use " glow fuel" : methanol + 5 to 15 % nitromethane + 16% minimum synthetic castor oil lubricant.
  • J/ccfam = energy in Joules per cc of fuel-air mixture
  • J/ccfam = ( power_in_watts x 60 x 2 ) / (capacity_in_cc x rpm ) = measure of energy efficiency

4 Stroke engine

The O.S. Engines FF-300 radial engine from http://www.osengines.com/engines/osmg1300.html

4 Stroke engine

The O.S. Engines FF-320 " flat four" from http://www.osengines.com/engines/osmg1320.html

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SAITO
SAITO single cylinder engines

4 Stroke engine

The SAITO 180 engine.

Photograph from http://www.horizonhobby.com/Products/Default.aspx?ProdID=SAIE180

Saito Engine

Capacity

Weight

Power

Power-to-Weight

min rpm

max rpm

fuel efficiency

cc

kg

kWatts

kWatts/kg

J/ccfam

FA-45S

7.50

0.440

0.522

1.186

2,000

12,000

0.696

FA-50

8.20

0.435

0.634

1.457

2,000

12,000

0.773

FA-56

9.20

0.410

0.671

1.637

2,000

12,000

0.729

FA-56F

9.20

0.410

0.671

1.637

2,000

12,000

0.729

FA-62a

10.24

0.469

0.746

1.590

2,000

12,000

0.728

FA-65

10.60

0.550

0.708

1.288

2,000

12,000

0.668

FA-72

11.80

0.470

0.895

1.904

2,000

12,000

0.758

FA-80

13.10

0.540

0.969

1.795

2,000

12,000

0.740

FA-82a

13.80

0.453

1.119

2.469

2,000

12,000

0.811

FA-91S

15.00

0.555

1.193

2.150

2,000

11,000

0.868

FA-100

17.10

0.551

1.342

2.436

2,000

11,000

0.856

FA-120S

20.00

0.900

1.641

1.823

1,900

10,500

0.937

FA-125a

20.52

0.700

1.641

2.344

1,800

10,500

0.914

FA-150

25.00

0.852

1.864

2.188

2,000

10,500

0.852

FA-180

29.10

0.881

2.088

2.370

2,000

10,000

0.861

FA-220a

36.30

1.100

2.610

2.373

1,900

10,000

0.863

Notes:

  • All Saito engines use " glow fuel" : methanol + 5 to 15 % nitromethane + 16% minimum synthetic castor oil lubricant.
  • J/ccfam = energy in Joules per cc of fuel-air mixture
  • J/ccfam = ( power_in_watts x 60 x 2 ) / (capacity_in_cc x rpm ) = measure of energy efficiency

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SAITO multi-cylinder engines

4 Stroke engine

The "vibration-free" SAITO FA-182TD

from http://www.horizonhobby.com

4 Stroke engine

The Saito FA-300T twin engine

from http://www.horizonhobby.com

4 Stroke engine

The SAITO FA-170R three cylinder radial engine.

Photograph from http://www.horizonhobby.com

Saito Engine

cylinders

Capacity

Weight

Power

Power / Weight

rpm range

fuel efficiency

cc

kg

kWatts

kWatts/kg

k rpm

J/ccfam

FA-60T

2

10

0.75

0.671

0.894

2 - 10

0.895

FA-100T

2

16.4

0.82

1.044

1.273

2.5 - 10

0.848

FA-170R

3

27.8

1.3

1.491

1.147

2 - 9.5

0.753

FA-182TD

2

30.0

1.04

1.864

1.792

2 - 10

0.828

FA-300T

2

50

1.75

3.504

2.002

1.8 - 8

1.168

FA-300TD

2

50

1.85

3.579

1.935

1.6 - 8.4

1.136

FA-325R5

5

53

2.41

2.834

0.971

1.7 - 7.5

0.951

FA-450R3

3

75

2.9

4.101

1.414

1.2 - 8

0.911

4 Stroke engine

The Saito FA-325R5 radial engine, from http://www.horizonhobby.com

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Engine trends for four stroke engines

4 Stroke engine

Pout scales with engine capacity as Pout = 0.073 * x + 0.031 for Pout in kWatts, where x is the engine capacity in cc.

4 Stroke engine

The average power-to-weight ratio for the above engines is 1.727 kWatts / kg. The superiority of the Saito engines in respect of power-to-weight ratios is clear.

4 Stroke engine

The average engine efficiency for the above engines is 0.813 J / ccfam. For the Saito engines, we notice the engine efficiency saturates for engines with a capacity of 17 cc and above.

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