Rotary aircraft engines

[Guest disperse]

Have received a little more info on these engines (twin rotor only)

 

the 130hp non turbo is a fair option for the J3300 .... but the turbo 180hp would be a lot of fun if the kit can handle it ... ???

 

http://www.rotaryaircraftengines.com/enginemodels.htm

 

$14995us and $19995us

 

including reduction drive and fuel injection

 

and oil consumption is a low 200 to 1

 

 

[Downunder]

Looks good but they need to get some flying examples out.

 

Then point out the aircraft that have done a couple of thousand hours.

 

Hours in the air is what counts.

 

Need to prove the design.

 

Not knocking them, but a couple of static pics of engines in aircraft doesn't really do it for me.

 

 

[Guest disperse]

Short Rotamax video

 

Found this short vid

 

Brightcove.TV Is Off The Air

 

 

[Ultralights]

i heard right! an install in a sadler vampire!! YAY, im not sure about an all aluminum rotary, but any mazda rotary, and i will fly with it, having owned a mazda 12A rotary and driven it over 300,000 km without fault, and then to be able to drive it home for 200 km at highway speeds, after it blew up! i would definitely put a mazda rotary in an aircraft!

 

though their single rotor 60 hp version in a vampire was $7200, i could almost buy 2 rotax 503's

 

 

[Guest disperse]

I in the other boat, comparing with a Jab 3300 and the twin rotor is $5000 cheaper !

 

and was reading that even if you cook it it won't actually seize, and will still run !

 

 

[eyecast]

Very Very interesting.

 

HP to Wt looks good.

 

Just have to get the hours up it would seem.

 

:pig::pig::pig:

 

 

[Ultralights]

cooking a rotary engine is very bad, as they are made up of what is effectively layers of aluminum and steel, the alloy front plate, steel rotor housing alloy mid section, another steel rotor housing and a third alloy section, unfortunately aluminum and steel have different expansion rates, and all combustion heat is generated on 1 side of the engine, hence the need to ensure they are adequately warmed up before driven hard. if they over heat, and with the resultant differing expansion rates, the damage caused is usually endplate seals and side seals failing,usually in the water jacket area resulting in loss of compression and water entering the rotor housing causing hydraulic lock. not good.

 

A rotary engine will continue to run after a rotor tip seal failure, or any other failure in 1 rotor housing, as the good rotor will continue to provide power, the damaged rotor chamber will usually have no compression left as the rotor seals will destroy themselves, allowing the good rotor to provide its full power potential.

 

when my rotary engine died at 330,000 km, what happened was the housing chrome steel lining eventually wore through, resulting in a piece of the chrome plating braking off the lining and entering the chamber, and destroying all the rotor tip seals, when this happened i was in Newcastle, even with 1 rotor housing and rotor doing nothing but making grinding noised, i still managed to easily drive 250 km back home, and easily maintained 110Kph

 

a few minutes after the failure, all the loose tip debris and housing lining pieces, left the chamber and sat in the exhaust manifold, the engine didn't sound that bad after that, just like a constant missfire. yet it still made good power.

 

the reason for the failure as mentioned was the chrome lining wearing through in the rotor housing, the reason it did this, is that about 300,000km is as long as they will last when the engine is looked after... similar to the piston rings in a conventional engine wearing through the cylinder wall liner.

 

 

[Downunder]

I see they have a 130 HP "economy" engine (carby & single spark) for $6600us.

 

http://www.rotaryaircraftengines.com/PDF/RotarySpecSheet.pdf

 

 

[Guest Flyer40]

Good find Troy. I would also like to see them with some runs on the board and I wish them every success. The smooth running of a rotary appeals to me, particularly since with this engine they seem to have got the notoriously high fuel consumption of a rotary down to about the same as a Jab 3300 for the same hp. I hope that's genuine.

 

The alternative fuels research is also very interesting.

 

Do you know what kind of controller they use for the EFI? I'd be even more interested in this engine if they run an automotive CAN network with OBD-II port.

 

 

[Guest disperse]

I can't take the credit for the find as there is a post in here somewhere that made me aware of them..

 

I'm courious about thier injection system to (not that I know a lot about them).

 

and I'd like to know about iceing problems

 

But I do know that there running standard unleaded.

 

 

[Ultralights]

funny how they have single spark plug option.... i would prefer 2. its with 2 plugs that mazda managed to get the consumption and exhaust emissions to acceptable level, leading plug fires, followed by the trailing plug, and the leading plug fires a second time as the exhaust port is uncovered, will, it does in my 13B 6 port anyway.

 

are the engines mentioned above copies of the mazda design? or a totally new design on the same principal of the mazda engine?

 

 

[facthunter]

suitability for aviation.

 

I've consistently believed in the suitability of the Wankel design rotary for Sport aviation.

 

some points;

 

Noise... Like a two stroke it is noisy and needs a carefully designed muffler.

 

Fuel consumption.... Could never be as good as a conventional piston engine (all other things being equal) because of the large surface area of the combustion chamber, in relation to its volume. Inherent design disadvantage.

 

Cooling ....is difficult because of the concentration of heat near the exhaust port, almost rules out air-cooling. (esp. the larger units)

 

Cost ... Development of good surface treatment of wearing and sealing surfaces, and control of distortion due to uneven heating. Most of this development has already been done.These engines will be price-competitive.

 

Reduction gearing..... Has to be easier than reciprocating engines with their torsional vibration problems.

 

Vibration ...Relatively good.

 

Reliability....GOOD.probably potentially the BEST. (exc. turbine).

 

Size & weight.... only bettered by a turbine, but they cost and use lots of fuel.

 

I reckon that it's only a matter of time. Nev..

 

 

[Guest disperse]

funny how they have single spark plug option.... i would prefer 2. its with 2 plugs that mazda managed to get the consumption and exhaust emissions to acceptable level, leading plug fires, followed by the trailing plug, and the leading plug fires a second time as the exhaust port is uncovered, will, it does in my 13B 6 port anyway.are the engines mentioned above copies of the mazda design? or a totally new design on the same principal of the mazda engine?

These are the Rotamax engines. They purchased the design from OEM (Johnson / Evenrude ) .......There is a fair bit of info on there SITE

 

At first I got excited about the turbo charged version @ 180hp. And about the same weight as a Jab 3300. But I think G Morgans Sierra would need a little more modification to handle a 160kt cruise.

 

But if I was to fit the 120hp rotamax ... The difference in price would pay for the CS prop, and it is much easier to get a CS prop for a reduction drive than a direct drive boxer engine.

 

These engines have a charge cooled rotor. Which means that the intake mixture is ported through the rotor to help cool it. Also has a water cooled housing. For this purpose I was thinking of a airscoop for the intake. (coldest air ) But this raises questions about iceing. Does anyone know how ice affects EFI ?

 

 

[Ultralights]

no icing problems with EFI, as there is no fuel mixture with the air to lower its temperature below freezing, and when the fuel charge meets the air, its just as its entering the cylinder, where the air charge as already passed into the manifold system and would be considerably heated.

 

 

[Guest Flyer40]

Icing shouldn't be problem with efi, it's generally related to the pressure drop in the venturi of a carby. Could be a couple of rotary sierra's in our future huh?

 

EDIT: we were writing at the same time.

 

Nev, they sound like two strokes because they are two strokes.

 

 

[Guest disperse]

Thanks all for the info ....... Just need money now !!!

 

 

[Guest ROM]

Wankel based designs run on the four stroke principle which is what Rotomax also quote.

 

They are a fabulously smooth running motor with a turbine like acceleration which just never seems to stop.

 

Many years ago my brother had a little rotary Mazda RX4.

 

He regularly would hit 100mph, 160 clicks, no K's in those days, and then drop it into top gear.

 

The old man admitted to hitting 150 mph in it before he chickened and she was still winding up without any slackening.

 

Drawbacks were the lack of peripheral rotor seal life, corrugating of the rotor housing where the seals ran and high fuel consumption.

 

The high fuel consumption may have had something to do with the fact that all the lads [four of us plus the Old Man ] of the family who could lay hands on it drove it like a bat out of hell because that was how it felt!

 

That was a long time ago and a lot of water and research dollars have flowed since then so a lot of these problems should have been sorted out by now.

 

The Rotomax could turn out to be a very good light aircraft engine when the bugs are fully sorted.

 

The main drawback will be higher fuel consumption but in the days of rapidly increasing prices, I think the Rotary can be easier modified to handle a variety of fuels than can the convential piston aircraft engine, particularly with the FI version.

 

 

[Guest Flyer40]

There's a bit of ongoing debate around wankel engine terminology. A rotary is not a four stroke as such. While it is a four (Otto) cycle engine, its quite unlike the traditional four stroke engine that completes one combustion cycle for every two rotations of the crankshaft. A rotary completes a combustion cycle every crank rotation. Which is essentially the same as a two stroke. It also uses porting rather than valves, again like a two stroke. This is why many consider them two strokes and why they sound like two strokes. It's also one of the reasons they use more fuel.

 

Some use the four stroke reference to rotaries due to the crank making three revolutions to each revolution of the rotor. But that doesn't make a lot of sense to me.

 

The point that ultralights made about rotaries being unlikely to suffer a terminal failure is I think what makes them such a good choice for aircraft.

 

 

[Ultralights]

i have a few brilliant animated Giff files that show the rotary cycle in good detail, now if only i could post an animated giff file in the thread...

 

 

[facthunter]

2-strokes

 

Flyer 40, I don't disagree about them being 2-strokes, but the noise is due to the fact that a pretty big hole opens up when there is quite a bit of pressure. They can (unlike MOST 2-strokes) be supercharged above atmospheric so a LOT of power (and noise) is available. I emphasize the noise because it has to be dealt with and the weight of the exhaust system has to be part of any comparison with other engines. It's good to see a lot of genuine interest in these powerplants, as they deserve serious consideration for our type of work, reliability being a big PLUS. Addendum The term "rotary" probably correctly relates to the radial motors that rotate around a fixed crankshaft and have names like Gnome et Rhone, Clerget , Bentley, Siemens-Halske and others . As hope springs eternal in the human breast, perhaps we should reserve the name Rotary for the "real" thing in case someone makes some of them. Nev...

 

 

[Ultralights]

here we go, 2 good videos that should answer most questions, the first is a overview, and the second video is a more in depth animation of how the engine is constructed and works.

 

https://www.youtube.com/watch?v=oGrD7FTFLJc&feature=related"

 

https://www.youtube.com/watch?v=TxqCtXVJoEY"

 

hope these help.

 

 

[vk3auu]

What give you the idea that two strokes can't be supercharged. The big GM diesels that the railways run have a dirty big Rootes blower feeding air into the cylinders. It might be a bit harder with a carby, but still not impossible.

 

David

 

 

[Guest Flyer40]

Good point David. The blowers on the GM V16 only really assisted with scavenging and didn't pressurise the cylinder much above atmospheric. As such they were still considered naturally aspirated. But the later and current versions of the same two-stroke engine are turbosupercharged with a turbo that is gear driven at low rpm to act as a blower.

 

 

[facthunter]

Pressurise

 

vk3auu they are scavenged, not pressurised. I don't deny that they have"as you say , a dirty great blower" but I did say "most" and I used the term, ABOVE atmospheric Nev..

 

 

[hiperlight]

Hiperlight II with Wankel Rotary

 

A few years ago a Hiperlight II was fitted with a Wankel Rotary (twin). I don't have much info on it...here is a photo taken at Oshkosh.