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Posted

To me, it appears there's an inadequate level of cooling fins in the head area. Compare it with say, many other air-cooled engines, they have a very sizeable number of fins all over their heads.

 

The bottom line is the combustion chamber is where the heat is being generated, so you need those big fins all around that area.

 

http://www.enginehistory.org/Piston/ACEvolution/ModernCyl.jpg

 

http://www.enginehistory.org/Piston/ACEvolution/ACA-40.jpg

 

 

Posted

That Taiwanese engine seems to have an alternator under the flywheel (thus concentrating all the innertia storage in one area) avoiding Jabiru’s “mistake” of having them at opposite ends of the crank.

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Posted

Cylinder design similar to a Franklin. One piece eliminates a  common problem. Thats the best starter arrangement there is and a belt driven alternator too. Direct drive too. Keep your eye on this one.   Nev

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Posted

I'm just not excited. I used to be excited, but just can't seem to find the inspiration to get excited here.

 

We still have not yet seen the 115hp 250cc multi cylinder honda enya aerosport motor come out of japan. And we are all still eagerly awaiting the 225hp single cylinder side valve DangDeng ductile iron motor to ship from north korea. Iran are refusing to release any of their rebadged stolen rotax rebirth units due to sanctions. And the soviets flatly continue to refuse to reconsider everything under 12000hp as an insult to aviation.

 

Just not excited. Going out to the shed to listen to 2GB and play with the victa again.

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Posted

I’ll get interested when they have sold 10,000 units and half of them are past the 2,000h mark. Until then, it’s all marketing. 

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Posted

From the website - "In recent years, the new crown pneumonia epidemic has shrouded, but our engines are not infected and continue to conduct various performance tests"

I must say I especially like to have MY aircraft engines not infected with any virus.

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Posted

So! what's new or differently applied technology, in this engine? Its price is attractive but so what, other engines are similarly priced. 

 

If it was liquid cooled, with variable ignition and overhead cam, driving the prop through a innovative gearbox, with an all up weight equal/better than the industry leader - then it might just  be of some passing interest.

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Posted (edited)

 Pretty big condemnation from our team of experts . At least the exhaust ports have More finning than the Inlets  and there's excellent heat flow through the entire Head/barrell connection being ONE piece. No pipes all over the place either and the fuel is below the engine with a better designed intake and there will be little trouble with carb icing  It's power/weight is good and any gearbox is  using power and is an extra liability and cost and with it, you cannot use the prop as a flywheel..Nev

Edited by facthunter
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Posted

ADD when it is geared.    The aluminium is cast onto the iron like earlier Japanese 2 stroke triail bikes were and that "Joint" must persist or there will be distortion and hot spots. Those cylinders are probably done in metal dies which once made are cheap to produce in quantity and consistently. Sometimes referred to as  Vacu-cast. Little or NO porosity, but the bores will NOT be hard as the aluminium pours at above red heat  and anneals the iron. .Nev

Posted

And the engine also reverts to 1930's engine design practice, with severe limitations placed on valve positioning, thanks to the one-piece cylinder and head.

 

You can only position the valves directly in line with the cylinder in a setup like this, so the seats can be machined. That eliminates any ability to produce a better combustion chamber shape, such as a hemispherical chamber.

 

The engine has no major technological advances over anything previously produced, and offers no gains in fuel economy, no multi-fuel abilities, no forced induction for improved efficiency - in fact, it's a pretty ho-hum engine, as Skippy says.

Posted (edited)

Most radials have hemispherical heads and you can service the heads  but it's more difficult. It also allows larger valves but in line motors don't have the space the radial configuration allows. Having a head joint is not desirable. It's a weakness. This typeof motoris easily able to be supercharged if the extra heat is able to be handled. Just because it resembles the look of a 30's motor doesn't mean it is NOT a lot better than many  or all of them.

  It's in the metallurgy and cost control. It's not as if you have overwhelming numbers of good engines to pick from. There are far more failures than successes. in the modern  AERO piston engine arena.   Nev

Edited by facthunter
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Posted (edited)

Removing the head joint might have been desirable in the 1930's when cylinder-to-head sealing was a major problem area - but modern designs and materials have almost completely eliminated head gasket problems.

Having the freedom to design a head with a vastly improved and more efficient layout and shape, and which is able to be quickly and easily removed to check for problems (and is easy to repair), is a big step forward from a one-piece cylinder and head.

My prediction is that this engine won't even make a measurable dent in established light aircraft engine sales. It's not like it's got major cost advantages, either, it's still pricey for what it is.

 

Edited by onetrack
Posted (edited)

Being non mass produced makes this type of motor always dearer than others and if there's any issues it's headlines. You can't be serious about head sealing and heat flow The OLD  90 degree valve inclination is long gone. Too much head  (combustion Chamber) area and the valves easily touch each other if one jambs. Flat top piston is least AREA ( heat )also.  Nev

Edited by facthunter
Posted
2 hours ago, facthunter said:

… the valves easily touch each other if one jambs. Flat top piston is least AREA ( heat )also.  Nev

My RVR diesel stopped running after the cam chain broke. I removed the head, replaced chain, guide and gasket. Did not touch the head; the flat-topped pistons must have just punched the parallel valves with no damage.

I put it back together and it ran for years afterwards.

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Posted

You're a bit lucky to get away with that, Maybe the Valves were a bit pocketed A diesel head is usually just flat.  Nev

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Posted

Screw all this, i'm relocating to an undisclosed pacific island atol with my freshly developed 125hp plutonium pico reactor powered stol lightwing and box of iced vovo's.

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Posted
22 minutes ago, Area-51 said:

Screw all this, i'm relocating to an undisclosed pacific island atol with my freshly developed 125hp plutonium pico reactor powered stol lightwing and box of iced vovo's.

Take some TimTams as well for any necessary chocolate fix’s.

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Posted

I think it's good that people still try to make a cheap reliable motor for us to have a larger choice.. Jabiru lost the KFM when the makers  just stopped making it. Rotax have discontinued two of the three 2 stroke motors.  It's not as if the problem will just go away. it's an ever changing situation.. Nev

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Posted (edited)

mmmmm looks short on cooling surface area.-- but might be OK is the aluminium is the right type and cooling airflow done right. 

 

wonder how many bearings.

nice big pots.  (Lycoming) 

flywheel and prop together I like.  (Lycoming) 

carb attached to sump etc and inlets I like (a la Lycoming) 

single carb I like. (Lycoming) 

maybe a hot upgrade for 2200 jabiru powered beasts ?

 

HOWEVER not competitive with a 912..... so.... ?????

 

Edited by RFguy
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  • 4 weeks later...

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