Martin Jetpack engine

[Oksinay]

V4

 

2 stroke

 

60Kgs

 

200hp @ 6,000rpm

 

Designed from scratch for aircraft applications, "high reliability, flat torque curve"

 

Too good to be true?

 

 

[jetboy]

Does it come with Jabiru mounts?

 

 

[bexrbetter]

V42 stroke

60Kgs

 

200hp @ 6,000rpm

 

Designed from scratch for aircraft applications, "high reliability, flat torque curve"

 

Too good to be true?

Nothing hard about 200 neddies from 60kgs in a 2 stroke package, it's acceptance that's the issue - "smelly, smokey, noisy, unreliable ...... blah, blah, blah" waffle based on myths and lores. Go have a look at Evinrude's website and try to find the actual words "2 stroke" mentioned anywhere ... mind you, Martin's "100 hour TBO" doesn't help the cause!

 

I love 2 strokes, my built engines and pipes have held Australian National and Qld Road Racing and Motocross titles and I would love to build an aero 2 stroke engine and would do it in a nat's breathe if I thought they would be accepted. I have a couple of designs already mapped out and was playing with the idea as recently as last week ..

 

http://rbcylinder.en.alibaba.com/product/2002113028-221231704/Ceramic_Nikasil_cylinder_76mm.html?edm_src=sys&edm_type=fdbk&edm_grp=0&edm_cta=read_msg&edm_time=realtime&edm_ver=e

 

Does it come with Jabiru mounts?

Or Honda Z mounts?

 

 

[Guest ozzie]

When i had a look at the original martin jetpak when it debuted at Airventure 08 the first thing that the engine reminded me of was Evinrude V4 200hp. No mention if it was based on it or not but probably some internals are the same.

 

 

[facthunter]

I've spent years designing a two cylinder 4 piston Two stroke, but I reckon someone would find something wrong with it, or they would copy it in China. Nev

 

 

[Oksinay]

 

These guys think it comprises 4 Honda CR500 cylinders joined to make the V4.

 

 

[bexrbetter]

I've spent years designing a two cylinder 4 piston Two stroke, or they would copy it in China. Nev

You couldn't show us the plans there could you Nev, won't go further than the forum ...

 

Rather than being fearful of "China", learn how to use it to your advantage.

 

These guys think it comprises 4 Honda CR500 cylinders joined to make the V4.

Probably, easy 200hp for sure, right for the jetpack but wrong for a light plane. Also much heavier with the individual cylinders.

 

Strange as there's a couple of very well known 2 stroke 'from scratch' developers in Enzed and smarter people would have used 3 cylinders, not 4.

 

 

[Guest ozzie]

3 cylinders. I have owned several 3 cylinder two strokes . Wooohooooo.

 

 

[Downunder]

3 cylinder...... firing 120 degrees apart?

 

Anyone ever made a 2 stroke radial?

 

Edit. I guess there is, but small.... http://www.compactradialengines.com/mz570.html

 

 

[Geoff13]

3 cylinders. I have owned several 3 cylinder two strokes . Wooohooooo.

I don't know about 3 cylinders but the old RD350 would be the only motorbike that ever bested me. It was a mongrel in the purest sense of the word. It seemed every time I got astride her she threw me. But hell I had fun trying.

 

 

[bexrbetter]

3 cylinder...... firing 120 degrees apart?

Yup, exactly. Can gain a decent increase in horsepower due to the ability to use exhaust pressure waves of a previous exhasted cylinder to enhance the currently filling cylinder. Minor reversion supercharging but not nearly as effective as an expansion chamber.

 

That's only an advantage if you don't have the ability to use individual expansion chambers and note that 3 CR500 engines make 200hp standard from 1500cc with chambers rather than Martin's 4 cylinders and 2000cc. For their application though, 3 expansion chambers would be difficult to package. I would suggest they could have gotten around 180hp using just 3 cylinders with good packaging, maybe it wasn't enough though.

 

And just to show the potential, the last years of 500cc Moto GP were regularly getting over 200hp from their 500cc 4 cylinder engines, but you can see here just how difficult it is to package the 4 chambers and for the Martin application the chambers would have to be substantially larger for the required lower rpm power band.

 

 

 

 

[Guest ozzie]

3 cylinder...... firing 120 degrees apart?Anyone ever made a 2 stroke radial?

 

Edit. I guess there is, but small.... http://www.compactradialengines.com/mz570.html

Konig has a few.

 

 

[Guest ozzie]

I don't know about 3 cylinders but the old RD350 would be the only motorbike that ever bested me. It was a mongrel in the purest sense of the word. It seemed every time I got astride her she threw me. But hell I had fun trying.

RD series were good bikes and many riders had their start road racing with them . The Kawasaki Triples were all the fastest in the classes but the spaghetti frames let them down. Wish i kept mine i have been looking around for a H2 750 recently and good versions are around 20 grand today.I bought my first H2 new for $1200 in 73. Other 3 cylinder 2 strokes were the Yamaha TZ series all race bikes.

 

 

[Downunder]

Konig has a few.

Looks like the "compact radials" are actually the Konig engines acording to wiki.

 

Konig sold the rights to an Italian company who then sold to Compact Radials..........

 

 

[bexrbetter]

RD series were good bikes and many riders had their start road racing with them . The Kawasaki Triples were all the fastest in the classes but the spaghetti frames let them down. Wish i kept mine i have been looking around for a H2 750 recently and good versions are around 20 grand today.I bought my first H2 new for $1200 in 73. Other 3 cylinder 2 strokes were the Yamaha TZ series all race bikes.

Sorry Ozzie but no, TZ's were either 2 cylinder (250 and 350) or 4 cylinder (500, 700 and 750)

 

I have worked on many a RD, RZ and TZ 250 and 350 as I did my first apprenticeship in a Yamaha dealership. My own RZ 350 was one of my favorite bikes of all.

 

Kwaka triples were around a long time, awful bikes, bad frames and no brakes, killed a lot of blokes. The Suzuki range were more sensible and the GT750 "Water Bottle" took many people around many countries reliably. The smaller air cooled ones, GT380 and GT550, ran the "Ram Air Cooling" scoops on the heads. There's plenty of bits around for the water bottle still and would make a great foundation for an aero engine.

 

 

[Guest ozzie]

TZs, I never had the chance to ride one, always thought they were three cyl. they went like cut snakes

 

I loved my H2 73 blue model. Also had a orange 250 first disc brake model and a 400. Main problem i had with the H2 was the cops following the blue haze home as they sure as hell couldn't keep up with it.

 

Water bottle was a nice tourer that you could wind up but top heavy like a Honda 750/4.

 

ended up selling them all and bought a panel van, parachutes and a hang glider. Can't believe how much a H2 and others from that time fetch these days

 

 

[bexrbetter]

Can't believe how much a H2 and others from that time fetch these days

Yup, true, did you know that most of them go back to Japan? They are crazy for the original superbikes and they pay top dollar - many have gone back from Australia, even models they never sold in Japan in the day as they had a 750cc limit with an exemption for Harley.

 

 

[Guest ozzie]

Yes, and some have been imported from the US recently for rebuild. Non Oz models have solid capacity emblems on the side covers instead of the transfers and some other subtle differences. A friend had an imported Japanese version 750 Kawasaki that was almost identical to the Z1 900.