AeroTwin Engine Specifications:

General Specifications:
• 65 HP @ 4200 RPM
• Weight: Less than 95 lbs "Ready to Run"
(Includes cooling shroud, exhaust and oil reservoir)
• Dimensions (Height): 17.5"
• Two Cylinders, In Line
• Dry Sump (Runs in Vertical and Horizontal position)
• Air Cooled 972cc 4 Stroke
• Firing Angle 360°
• Bore: 101.6
• Stroke: 60mm
• Compression Ratio: 8.0:1
• Manifold Pressure: 8 psi
• Two Sparkplugs per Cylinder
• Two Valves per Cylinder
• Belt Driven Twin Camshafts
• Electronic Fuel Injection and Ignition
• Fuel Octane Requirement: 91UL
• Gear Reduction Box: 18.5lbs (see detail below)
• Propellar Flange: standard output flange has 75mm and 100mm bolt-circle
pattern for mounting, an aircraft standard SAE No.2 propeller flange is also
available as an option

Detail Specifications:
• Intake Valve dia ... 46mm / Exhaust ... 40mm
• Intake Port dia ... 38mm / Exhaust ... 34mm
• Intake Cam lift centre ... 102°
• Exhaust Cam lift centre ... 112°
• Total lift Inclusive ... 10mm
• Included Angle ... 32°
Feature Note: The cylinder head is designed to allow it to be rotated 180°
so that intake and exhaust positions can be changed.
• Piston Type ... Shallow Slipper
• Piston Pin dia ... 22mm
• Connecting Rod Centres ... 120mm
• Connecting Rod Material ... Titanium (Ti 6AL 4V)
• Connecting Rod Crankpin dia ... 50.8mm
• Crankshaft Material ... Titanium (Ti 6AL 4V)
• Crankshaft Main Bearing dia ... 58.42mm
• Crankshaft Number of Bearings ... 3

• Gear Reduction Box Ratios:
------ 22x47 =2.136
------ 23x46 =2.000
------ 24x45 =1.875
------ Thus for a Prop speed of 2000rpm;
------ 2.136 =4272rpm
------ 2.000 =4000rpm
------ 1.875 =3750rpm
------ Prop speed of 2200rpm
------ 2.136 =4699rpm
------ 2.000 =4400rpm
------ 1.875 =4125rpm
------ Prop speed of 2500rpm
------ 2.136 =5340rpm
------ 2.000 =5000rpm
------ 1.875 =4687rpm
Feature Note: The gear centres remain the same for all ratios, so it's just a
gear pair to change from one ratio to another. All of the bearings have slip fit
mounting clearances, as does the drive shaft, so the system requires no
pressing or heating to change a gear pair. The casing is sealed with one
perimeter Oring, so there are no gasketing issues to contend with.