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Kevin Armstrong
29th March 2010, 12:17
http://www.flydiver.com/HTML/JCV-360Specs.htm

Spotted a new Verner engine on their website; liquid cooled flat twin, very light indeed; perfect for SSDR trikes as air cooled is patchy for reliability.

Is this what the HKS should have been?

Kev

Attached files brochurejcv-360.pdf (http://cloudniner.co.uk/images/converted_files/77450=5921-brochurejcv-360.pdf) (124.9 KB)

dirtbikebf
29th March 2010, 15:13
Seriously high RPM... only 180cc... Love to hear that going, would bring a new sound to microlighting reminicent of what the Honda RVF brought to bikes...

Kevin Armstrong
29th March 2010, 19:55
Hello Brian

If you do the math its 175cc in each cylinder, or near enough 350 cc; that's 62mm bore x 58mm stroke each pot.

That's about 100bhp per litre, pretty conservative in the motorcycle stakes. (My bike's the soft tune version at 675cc and 100bhp, the sports is 120bhp or 178bhp/litre)

Looks to me like they've done the same trick as the old aircooled unit; used off the shelf parts bolted onto a custom cast or CNC crankcase and crank, this time liquid cooled to get the horsepower per cc up.

This looks like two 175cc commuter bike unit barrels and heads, each producing max 17.5bhp with 14.5bhp continuous.

Again equivalent to a commuter bike in fast cruise, and a softer state of tune than a 125 learner legal bike.

That engine would shave ten or twelve kilos off the average weight of a 447 on a Chaser, and put it straight inside the SSDR weight and wing loading limits, yet keep the pod and so on.

If it's real, it's big news.

Kev

PS they mailed back to say

Price e4,480

Exhaust e250

35bhp @7,500 rpm (max 5 mins)

Max continuous 29bhp @6,400 rpm

Engine Dry wt 26.7kg

Exhaust 1.58kg

Water Cooler wt 0.75 kg

dirtbikebf
30th March 2010, 08:39
Hello kev

Ahhhhhhhh...

Forget to switch the brain on some days...

I have recently been looking at the engine on the Verner site and only done half the maths... it's a twin of course and now the 360 name makes sense! As a previous owner of a verner engined x'air and contrary to popular sentiment, I am a bit of a fan of the simple engineering philosophy they employ, their customer support is good also.

We just need a dealer in this country to stock a couple now, maybe I could persuade a loan of one to bolt on my SSDR Trya, I'd happily give it a go.

Cheers

Brian

Kevin Armstrong
30th March 2010, 11:55
If they are right about the weight, a standard permit single seater Trya was around 126 kilos; target weight for SSDR was 110 kilos as the wing was 11 square metres

Using that engine saves around 13 kilos over the 447, plus the iron engine mount was 'orribly heavy; three kilos should be pretty simple to shave off with plastic wheels, and maybe alloy instead of steel wing hang bracket cheek plates. I'd also bin the strut suspension and go for Chaser style bracing wires.

That would be a nice little machine with a big fuel tank and luggage space too. Quite the SsdR tourer we've been looking for.

Who's first for the plunge? I didn't know the backup was so good.

Cheers

Kev

PS it would be wise to bargain out of them the origin of the motorbike parts though, so that spares can be had if the Czech company disappears...


Brian Fallows wrote:
Hello kev

Ahhhhhhhh...

Forget to switch the brain on some days...

I have recently been looking at the engine on the Verner site and only done half the maths... it's a twin of course and now the 360 name makes sense! As a previous owner of a verner engined x'air and contrary to popular sentiment, I am a bit of a fan of the simple engineering philosophy they employ, their customer support is good also.

We just need a dealer in this country to stock a couple now, maybe I could persuade a loan of one to bolt on my SSDR Trya, I'd happily give it a go.

Cheers

Brian

Bill
30th March 2010, 13:15
I still don't like the price tag - since the 447 is much less than half that. Does anyone know of any good (small) epicyclic gearboxes so that a decent motorbike single can be clagged to it.

Duncan Couchman
30th March 2010, 13:33
Bill for that sort of power would a belt drive not be a lighter cheaper option?
When you say a 447 is less than half the price is that a complete engine, box, carbs and everything or just a bare motor?
Also would not a lot of the savings not be eaten up by having to remove the original gearbox and sort out new crank cases?
I think that the days of really cheap engines are over. Even if the base engine is cheap by the time you've mucked about making it suitable for aircraft and given the very small customer base the unit cost is going to be quite high.

I hate these engine threads I always come over as really negative. I'm not, honest, but I just don't see cheap power being an option these days.

I'd love to reengine my S5 but the MZ201 is about 3.5K, the rotary thing is around 5K and solo is around 3.5K It just doesn't make sense on an aircraft with a value of 2.5K.

Dave Smith
31st March 2010, 16:34
Belts have a huge advantage (especially V-belts), because they absorb the torsional vibration between prop (=flywheel) and engine (crankshaft accelerates/decelerates between power strokes). The Rotax boxes just about crack the problem with their dog clutch and cush drive, but there have been many casualties on the way. Witness the Hewland two-stroke gearbox in the ARV Super 2. It kept breaking - and Hewland's speciality was racing car gearboxes!

We used to get considerable wear on the teeth of the alloy toothed belt pulleys due to abrasive runway dust. That's why I prefer V-belts to toothed - plus they're more elastic - despite extra weight and slightly lower efficiency.

Dave

Kevin Armstrong
14th April 2010, 20:33
Hello Dave, I'd appreciate your input.

Jezza Harris was insistent that toothed high capacity belt was the way to go, but I'd got personal experience with the virtues of Polyvee in industrial applications, and they are certainly the thing they choose to use in car accessory dirves for long life where timing isn't a particular issue.

Even Paul Robshaw's earlier German Vee twin had Polyvee for the drive off the vee twin.

However toothed slender belts such as these

http://www.chris-knight-mcs.co.uk/acatalog/Belt_Drive_Conversions.html

seem to work well too.

I reckon the belt is a better drive if well designed than a gearbox; it only looks old-fashioned.

Kev

Bill
15th April 2010, 17:28
If Jezza says it's all right, that's good enough for me. Damn, it is a pity he does not join in any more - a very valuable member he was.

Mick Broom
16th April 2010, 09:35
Hi Dave,
Was the tooth belt pullies just alloy or anodized when you experianced the wear problems?
Mick

Dave Smith
11th May 2010, 09:23
Hi Mick,

No they were from the early days of microlighting - Robin engined Dragons and the like. They would be an unknown cast alloy, with no anodising. However, the people are still around so could be asked - Billy Brookes for the Dragon and Malcolm McBride for the Nicklow (could be the Dragon actually used the Nicklow reduction in any case??).

On reflection, the Nicklow prop pulley was very nicely anodised in a black colour, and didn't wear much (it's much larger, so you wouldn't expect it to). It was the crankshaft one with the staked on steel end plates that suffered.

The US imported toothbelts with the Gates semi-circular teeth were much less prone.

Dave

Mick Broom
12th May 2010, 07:29
Thanks for that Dave,
I will ask Malcolm as he works next door!
The belts are much better now and I would have thought hard anodising should help but as I am concidering a belt drive I thought I should get some background information if available.
Thanks
Mick

Kevin Armstrong
13th May 2010, 08:18
Hiya Mick, can't you just use the belt drive conversion sets they fit on various old Brit bikes instead of the primary chain drive?

At least they are already developed:-

http://www.norvilmotorcycle.co.uk/beltdrive.htm for the Norton Commando

Teaching my granny to suck eggs here so will shut up now...

Kev

PS I'd love to do what they did to that seaplane, stick the 912 on the keel low down and belt drive up to a high mounted prop.

Mick Broom
17th May 2010, 08:18
Hi Kev,
Quick answer would be weight!
It depends on your drive centres and ratio ( size of small pulley) on what you would use.
The drive on the hovercraft jumps when a fast change of speed is asked for , mind it has about 9 blades to get going.
Did a scheme which was lighter than the rotax box but run out of time, may be next year.
Awaiting a radial from overseas - no gearbox ;-)
Mick
having fun

Kevin Armstrong
17th May 2010, 08:39
Sounds like a slipper clutch is called for!

Noisy but chains are good aren't they?

Oilbath chain would be easier than gears and handle huge torque, easy to buy the sprockets too, but heavy (unless Renthal would knock up the big sprockets)

They used it on Range Rover transmissions didn't they?

Wonder if you could laser-cut a sandwich casing and use it as a structural prop bearing shaft support, with a thick spacer

Cheers


Mick Broom wrote:
Hi Kev,
Quick answer would be weight!
It depends on your drive centres and ratio ( size of small pulley) on what you would use.
The drive on the hovercraft jumps when a fast change of speed is asked for , mind it has about 9 blades to get going.
Did a scheme which was lighter than the rotax box but run out of time, may be next year.
Awaiting a radial from overseas - no gearbox /emoticons/wink.gif
Mick
having fun

Mick Broom
17th May 2010, 09:41
Hi Kev,
Construction engineering thinking I believe.
If the belt jumps or slips under start up then it already has a slipper clutch at the right price and weight. ;-)
Advantage over chains is the shock management. Chains would be good if the package needs to be small but would be no lighter.
Bits are no problem to manufacture in my business , I just draw it and make it .
Mick

Dave Smith
20th May 2010, 11:37
Len Gabriels tried chain drive on the early 210 Solo/Rowena powered Skyhook trike. Not good - as you'd expect - no torsional 'give' whatsoever. Vee-belts or Polyvee both qualify for 'slipping clutch' ;-) Hopefully, not too much. And whatever you do, NEVER use that non-slip spray gunk!

Dave