Water cooled engine for ultralight

[DYEATON]

What are some good water cooled engines to replace the rotax 503, that are not much heavier?

[Area-51]

 

Edited August 25, 2023 by Area-51

[Thruster88]

Would love to get my hands on an 850 etec for the thruster, would be epic.

 

 

[Thruster88]

15 hours ago, DYEATON said:

What are some good water cooled engines to replace the rotax 503, that are not much heavier?

The only one out there right now is a used Rotax 582, most users of Rotax 503 in Australia have made the switch over the last 20 years. This thruster which flew at Oshkosh in 1988, started life with a Rotax 503.

[facthunter]

2.5 times the current Power would be a change, but since they don't overspeed in a near-vertical dive, getting off the ground fast might be the most noticeable difference. It would be a change reducing the power so much once you levelled out.  Nev

[Litespeed]

I think you fellas have the wrong airframe in mind, but all's fair when "in thrust we trust".

 

My devious mind immediately jumps to a new FAI 300 kg record breaker.. High G, high Vne to take full advantage of such a powerful light engine. 

 

The Arnold Ar5 did 213mph on 65hp what could a 165hp more advanced design do?🤔

 

I am confident such a beast could blow the record easily. Anyone for 280mph?

 

Naughty thoughts I know, but damn that would be awesome.

 

 

[facthunter]

You will get a rough ride in most of those speed Machines.  Nev

[SAJ]

Even the 600 E-TEC would make my Thruster exciting. Betcha they wouldn't be cheap.

[Litespeed]

 Yes , it's a optimised for speed and light. It really would be a superbike weight and faster than a  hypercar in the air. 

 

It is a not meant for a luxury ride as a record breaker but could be throttled back for a smoother ride as a sport flyer.

It would be a burn holes through the sky machine. A more sane version at  240 mph would still be awesome 😎.

 

No it won't be a low speed pussycat but that's the trade-off. As a mini rocketship. No need to chase records, then build to 350 kg or more depending on range required. You travel a lot of ground at those speeds.

 

Why build a jet sonex when you could blow it away with a stroker far cheaper.

 

[Litespeed]

I bet a lot cheaper than a aero version by miles.

 

Naturally a Drifter with even the 125hp would be a real hoot on floats.

 

 

 

 

 

 

 

 

 

 

[Thruster88]

The Rotax E-tec 2 strokes are used in snowmobiles, they get close to 4 stroke fuel efficiency and electronic control means egt is correct so happy pistons. The is even a turbocharged version with 180 hp.

 

 

[facthunter]

Vertical twin 2 strokes with the 180 crank have a Lot of balance problems and an 850 is a whopper size for that type of motor,  Nev

[RFguy]

How about gearbox compatibility ?

 

[facthunter]

Always an issue.  Nev

[Area-51]

Its called Experimental Aviation for various reasons; people manufacture solutions to known design challenges

[facthunter]

Bu if they continue to re invent the wheel no progress will be achieved. IF it's TOO experimental  and you don't learn from the mistakes of others it will be self defeating and self limiting. Aviation got where it is by addressing emergent problems. Nev

[Area-51]

Learning never stops. Boundaries are there for the adventurous foolish and fearless to traverse them.

 

For everyone's safety and well being the only kind of human required to never ever attempt a traverse of a boundary is a bureaucrat.

 

The wheel is not being reinvented, just improved.

[Thruster88]

3 hours ago, RFguy said:

How about gearbox compatibility ?

 

Given the higher rpm of the etec compared to a 582 load factor on gearbox is about 1.6 higher than stock 582. C or E box would be ok at reduced tbo, my opinion.  

[facthunter]

That Motor has no flywheel at all and the  reduction gears would cop hell. You need pretty large gears to take that kind of Power continuously ALL gears absorb some power and get hot as a result.  Nev

[Area-51]

27 minutes ago, facthunter said:

That Motor has no flywheel at all and the  reduction gears would cop hell. You need pretty large gears to take that kind of Power continuously ALL gears absorb some power and get hot as a result.  Nev

Morse Hy-Vo; quiet, less friction, less heat, less weight, less maintenance. No idea why nobody is using it.

[facthunter]

Has been used with some motorbikes and transfer cases and can be pretty heavy for high torque used with . Falcon  timing drive . Better than roller chain in some applications... The absence of any flywheel is the problem. Can make motorbikes really nasty to ride. Nev

[Thruster88]

I am sure the E-tec engines have a similar flywheel to the 582, it is needed for smooth operation and the alternator. They are quite substantial.  

[Area-51]

The flywheel is the prop assembly same as the 912.

[facthunter]

A geared flywheel is a mechanical disaster . All piston engines have torsional harmonics.  Nev

[Thruster88]

1 hour ago, facthunter said:

A geared flywheel is a mechanical disaster . All piston engines have torsional harmonics.  Nev

The flywheel on 900 series and all the Rotax 2 strokes is at the other end from the gearbox. Proven over  many decades.