Hirth 3502
| Hirth 3502 & 3503 | |
|---|---|
| Type | Twin cylinder two-stroke aircraft engine |
| National origin | Germany |
| Manufacturer | Hirth |
| Produced | April 2008 - present (3502) |
The Hirth 3502 and 3503 are a family of liquid-cooled, in-line twin cylinder, two stroke, carbureted aircraft engines, with optional fuel injection, designed for use on ultralight aircraft and small homebuilts.[1][2]
Development
The engines were developed as competitors to the 64 hp (48 kW) Rotax 582 with an identical mounting bolt pattern to the 582, allowing either to be a drop-in replacement. The engines are similar to the Rotax powerplant in being liquid-cooled, two-cylinder in-line engines, with dual capacitor discharge ignition. The 3502 was developed from the 3503 as a de-rated version and produces 60 hp (45 kW), in comparison to the 3503's 70 hp (52 kW). Both engines have the same bore, stroke and compression ratio as the three cylinder in-line liquid-cooled Hirth 3701 and the bore, stroke, compression ratio and displacement of the twin-cylinder Hirth 2704 and Hirth 2706.[1][2][3][4]
Both the 3502 and 3503 are equipped with dual Bing 34 mm slide carburetors or optionally electronic fuel injection. The cylinder walls are electrochemically coated with Nikasil and the crankshaft is forged from 4130 steel. Standard starting is recoil start with electric start as an option. The reduction drive system available is the G-50 gearbox, with reduction ratios of 2.16:1, 2.29:1, 2.59:1, 3.16:1, or 3.65:1.[1][2]
The engines run on a 50:1 pre-mix of unleaded 93 octane auto fuel and oil, or optionally oil injection.[1][2]
Variants
- 3502
- Twin-cylinder in-line, liquid-cooled, two stroke aircraft engine with dual Bing 34mm slide carburetors or fuel injection. Produces 60 hp (45 kW) at 5000 rpm and has a factory rated TBO of 1200 hours. In production since April 2008.[1]
- 3503
- Twin-cylinder in-line, liquid-cooled, two stroke aircraft engine with dual Bing 34mm slide carburetors or fuel injection. Produces 70 hp (52 kW) at 6500 rpm and has a factory rated TBO of 1000 hours. In production.[2]
Applications
- 3203
- CGS Hawk Arrow II[5]
- Fresh Breeze XCitor - powered parachute[6]
- Paraski - powered parachute
- Steelbreeze - powered parachute[7]
- 3503
- XX-Style Power Cruiser Austrian flexwing microlight
Specifications (3503)
Data from Recreational Power Engineering[2]
General characteristics
- Type: Twin cylinder, two-stroke, in-line, aircraft engine
- Bore: 76 mm (3.0 in)
- Stroke: 69 mm (2.7 in)
- Displacement: 625 cc (38.1 cu in)
- Length: 398 mm (15.7 in)
- Width: 368 mm (14.5 in)
- Height: 419 mm (16.5 in)
- Dry weight: 79 lb (35.8 kg) without radiator & coolant. The G-50 gearbox adds an additional 19 lb (8.6 kg)
Components
- Fuel system: 2 X Bing 34mm slide type carburetors or fuel injection
- Fuel type: unleaded 93 octane auto fuel
- Oil system: 50:1 fuel/oil premix or oil injection
- Cooling system: liquid
- Reduction gear: G-50 gearbox with reduction ratios of 2.16:1, 2.29:1, 2.59:1, 3.16:1, or 3.65:1 or cog-belt
Performance
- Power output: 70 hp (52 kW) at 6500 rpm
- Compression ratio: 9.5:1
References
- ^ a b c d e Recreational Power Engineering (undated). "3502 water cooled 2 cycle 60hp". Retrieved 2009-12-22.
{{cite web}}: Check date values in:|year=(help)CS1 maint: year (link) - ^ a b c d e f Recreational Power Engineering (undated). "3503 water cooled 2 cycle 70hp". Retrieved 2009-12-22.
{{cite web}}: Check date values in:|year=(help)CS1 maint: year (link) - ^ Recreational Power Engineering (undated). "3701S - 2 cycle 100hp". Retrieved 2009-12-18.
{{cite web}}: Check date values in:|year=(help)CS1 maint: year (link) - ^ Ultraligero.Net (undated). "3701 - 2 cycle - 100hp". Retrieved 2009-12-18.
{{cite web}}: Check date values in:|year=(help)CS1 maint: year (link) - ^ Singer, S. Ben (2005). "Hawks at Sun N Fun 2005". Retrieved 2009-12-22.
{{cite web}}: Unknown parameter|Month=ignored (help) - ^ Fresh Breeze Powered paraglider (undated). "XCitor". Retrieved 2009-12-22.
{{cite web}}: Check date values in:|year=(help)CS1 maint: year (link) - ^ Steelbreeze (2005). "Hirth 3503". Retrieved 2009-12-22.