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Anyone tried a HKS700E engine!?!


Guest Katz
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I've flown a Pegasus Quantum HKS. My impression was of less power than the same trike witha 582 so I wasn't particularly impressed. However a brief test flight doesn't really let you appreciate the main advantage of better fuel economy.

 

There have been other threads on this theme - search for posts by Zulu (he flies an HKS trike in South Africa and is both more knowledgeable and a fan of the engine).

 

Cheers

 

John

 

 

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Thanks for your comment John. In india, it would not be possible to get a 912 since it is heavier than the HKS, and will not allow the trike to come below 375Kgs all up weight. That's why I have been trying to get some reviews about the HKS!

 

Thanks,

 

Karthi

 

 

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The HKS700E is a fine engine but it is not a 583 Rotax replacement, it is more of a replacement for the Rotax 503.

 

The best 4-stroke engine to replace a 582 Rotax is the Jabiru 2200 4-cyl 4-stroke, which is designed to weigh about the same installed.

 

The biggest problem with any four-stroke air/fuel/oil-cooled aircraft engine on a trike is getting sufficient airflow to cool the cylinder hads, especially around the exhaust valve area. I saw an HKS700E on a Pegasus trike and they had fitted little shrouds over the exhaust-valve area to try and capture air and direct it onto the fins for better cooling. That may work in British temperatures, but in mid-summer in Australia or India I very much doubt it.

 

The Czech Verner 2-cyl horizontally-opposed 4-strike engine is an 80hp unit, but likely to be a shade too heavy for trike installations. It is a very rugged and reliable engine..."built like a brick outhouse" I think sums it up pretty well.

 

 

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I know of 1 trike manufacturer who tried using the Jabiru - they spent ages experimenting but gave it up and switched to 912. AFAIK there aren't any Jabiru powered trikes in production ?

 

Another option might be BMW flat twin motorcycle engine http://www.huntwing.co.uk/bmw%20photos/The%20BMW%20story.htm

 

Or possibly the Mecedes SMART engine

 

Cheers

 

John

 

 

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Air-cooling a trike engine is a nightmare, and the only air-cooled engine that ever worked was the Rotax 503, which had fan-forced air-cooling. The problem is the airflow around any trike engine is chaotic after the air molecules have buffetted their way past the front of the pod, at least one occupant and then over, around or under an engine and into a propeller which is operating in some fairly disturbed air to begin with - hardly conducive to propeller efficiency. BTW, attempts to free-air cool the 503 usually result in a seized engine. The Rotax factory forced-cooling via the fan and the cowling on the cylinder-heads actually works better than anything anybody else has come up with. The moral of this is "if you are going to re-invent the wheel, be sure you know what colour it has to be before starting work".

 

The 582 works on trikes because it is liquid-cooled, and once the single radiator was replaced by the twin radiator the cooling in Australian summer heat was much improved.

 

The 912 also works because the troublesome cylinder-head area (where the exhaust valve is located) is liquid-cooled whilst the cylinder barrel is air-cooled. Once again, a decent radiator is required for cooling the fluid coolant (now Evans NPG+ instead of water and the usual ethylene glycol-based additive). Heat is rapidly conducted away from the head by the coolant, and the airflow around the barrels is sufficient, even without a plenum-chamber or ducts, to cool the cylinders.

 

The HKS will have siginificant cooling issues, as will the Jabiru engine, and the Verner, if it comes to that. Any free-air cooled engine will have issues, and they will be very difficult to completely overcome. Trikes are inherently prone to engine cooling issues by virtue of where the engine has to be located.

 

I think the trike manufacturers have shown us where the future of trikes lies; the Rotax 912, a well-matched propeller, and a well-designed base and wing. Ten years from now, that's where all trikes will be. Heavier (slightly), considerably more expensive, and with performance to dream of...and then someone will dig up some old plans and build a 95.10 trike and the whole evolutionary cycle will probably repeat itself. It is quite possible the next generation of trike pilots will yet again re-invent the wheel - and have the usual furious argument over what colour it should be.

 

 

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In a Jabiru J160 you need to maintain 70kts (absolute minimum)in a climb to ensure sufficient cooling of the motor, and thats in a config that has evolved for some time.

 

Given that most trikes will climb at 50-60kts and wont have the pressure differential that is afforded in the 3axis planes by the cylinder shrouds and low pressure in the lower cowls I to have problems seeing how this could be pulled off succesfully in an asthetically pleasing manner. A jaby engine in a trike that requires a forward facing air inlet that approximates a tuba isnt going to sell well....ever!. The bigger 120hp motor needs minimum climb speed of 80kts..... Mind you with 120hp you wont need to climb for long! before transitioning to faster cruise !!

 

Andy

 

 

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I saw one of the attempts to use a Jabiru on a trike - it had a HUGE set of fibre glass ducts to try & force air over the heads which were referred to as "Elephants Ears". Even that didn't (apparently) solve the cooling problems and it so horrible I can't imagine it appealing to anyone with eyesight good enough for flying !

 

Cheers

 

John

 

 

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HKS

 

Hiya

 

I have flown with my HKS 700e for 300 hrs, perfect, now its out of commission and in my garage for a fuel injection modification. Need that extra oomph for hot days. Better than 503 and not quite a 582..

 

Our RSA team came second in the worlds with one.

 

Go for it..

 

Cheers Paul

 

 

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Cooling of pushers.

 

Dieselten , a thoughtfull and well expressed contribution. All I can say is to anybody reading this thread do not try to ignore the obvious . You have to force air over a pusher or liquid cool it, You need control over the effect (either a thermostat or adjustable cowl gills) all increased complexity Nev..

 

 

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Thanks guys!

 

Hello guys.... have been travelling for the last few days, and am surprised to see lots of comments on my question! I still have some more -

 

- Most people comment on the "lower power than a 582" issue, but isn't it for sure because the HKS is a 4 stroke of nearly the same 60hp. power to power, the 2 strokes obviously will have better performance, right??

 

- (Dieselten) Isn't the cylinder heads of a HKS, oil cooled!?! Is this not sufficient for the cooling of the exhaust valves!?!

 

- (Zulu1) What sort of a trike did you have??? And how was the fuel consumption with your HKS?? Would be nice to know.

 

Katz

 

 

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Guest MundooTriker

Hello Katz,

 

If you are waiting for Zulu1, Have a look at the Thread on South African Trikes.

 

There seem plenty of good things about both the HKS and Aquilla Trikes.

 

Have a good day - Andrew

 

 

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HKS fuel consumption

 

Hiya

 

My motor is fitted to a Aquilla, with the 14 square metre wing, I live a sea level o the coast so no worries unless I fly inland (40 kms north of Durban). The motor is half way between a 503 and 582. It gives me solo however I thrash it about 6-8 litres an hour and dual about 9-10 litres per hour. Obviously cool days its more economical.

 

It has oil cooled heads and only draw back is its rough idle, now with the efi project I hope to improve its performance to at leaast match the 582. Otherwise you will not be sorry. Its a 4 stroke !!

 

Such a nice feeling flying over the ocean and looking at oil temp/pressure gauges..

 

Cheers Paul

 

 

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Fuel HKS700e

 

Its the same consumption as a 912, so how can you work that theory out, a two stroke pours a fair quantity of medicine down the exhaust !!

 

I have flown most trikes and their different motors (except the Verner) and found the HKS to be "adequate" with a much less weight (and price) than a 912. However saying that I still enjoy the 503 in light machines it revs freely and is simple.

 

Go fly one and then make the judgement..

 

Ciao Paul

 

 

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  • 8 months later...
Guest rocketman

Katz,you're India based, correct? What do you know of the Murti (?) car engine thats been converted to trike usage? I'm told someone did one over there. All aluminium car engine, with a reduction drive. The other option I'm thinking of exploring soon is the Suzuki Geo engine. I'll have to fish back through my past emails to find the one about the Murti car engine to verify details.Neale.

 

 

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