I’m considering converting an AC4 sailplane http://www.cocatrez.net/Air/Russia_AC-4B/Russia_AC-4B.html to twin engine power. The AC4 lacks a EASA type certificate so can’t be flown here. Experimental registration is not allowed so converting to a 3 axis ultralight is a way of flying it.
Design goals are to create a +160km/hr cruise single place aircraft, >500km range,<300m take off roll, >1.5 m/sec single engine climb @15deg C sea level, prop wash not to be felt on horizontal stabilizer, simple to remove engines, least intrusive to existing structure.
So far this is what I’ve come up with based on the Cri Cri idea but engines shoulder mounted. 2 Limbach 275E engines Limbach-Flugmotoren.de - L 275 E
A list of alternative Cri Cri engines was posted by Cazador on the Cri Cri engine thread https://www.homebuiltairplanes.com/forums/attachments/2-stroke-aircaft-engines/3462d1242360731-cri-cri-engines-cri-cri_engines_list.xls
Much cheaper Chinese built engines are available http://www.dle-engines.com/dleg0170.html. They could be used as proof of concept engines before venturing away from the airport.
In the shoulder mount configuration a good hard point to receive the engine pylon stubs is the center wing spar assembly pin. The pylons would exit the fuselage shell near the reinforced turtledeck to canopy joint and further reinforcement to the spar socket receivers would be a light and simple layup.
The pure glider has about 7.25 kg drag at best L/D 31 @ 95km/hr with 140kg empty weight + 85kg load = 225kg take off weight. Adding engine installation plus fuel 50kg would be 275kg max gross. At a reduced L/D of say 23 about 12kg thrust would be needed at 105km/hr to sustain.
Any comments would be welcome.
Dino
Design goals are to create a +160km/hr cruise single place aircraft, >500km range,<300m take off roll, >1.5 m/sec single engine climb @15deg C sea level, prop wash not to be felt on horizontal stabilizer, simple to remove engines, least intrusive to existing structure.
So far this is what I’ve come up with based on the Cri Cri idea but engines shoulder mounted. 2 Limbach 275E engines Limbach-Flugmotoren.de - L 275 E
A list of alternative Cri Cri engines was posted by Cazador on the Cri Cri engine thread https://www.homebuiltairplanes.com/forums/attachments/2-stroke-aircaft-engines/3462d1242360731-cri-cri-engines-cri-cri_engines_list.xls
Much cheaper Chinese built engines are available http://www.dle-engines.com/dleg0170.html. They could be used as proof of concept engines before venturing away from the airport.
In the shoulder mount configuration a good hard point to receive the engine pylon stubs is the center wing spar assembly pin. The pylons would exit the fuselage shell near the reinforced turtledeck to canopy joint and further reinforcement to the spar socket receivers would be a light and simple layup.
The pure glider has about 7.25 kg drag at best L/D 31 @ 95km/hr with 140kg empty weight + 85kg load = 225kg take off weight. Adding engine installation plus fuel 50kg would be 275kg max gross. At a reduced L/D of say 23 about 12kg thrust would be needed at 105km/hr to sustain.
Any comments would be welcome.
Dino
