henryfonda9

   There are many ways to express the "truth"  negative is just one option - some people choose that way a lot it seems.

rmh

cheer up 

pe reivers

Dick, Gotcha!
I said at same rpm, the twin wins over thefour. I said same RPM, not same prop! The 4 has more mechanical losses, which are compensated for by better breathing and lower piston speeds as rpm rise. At elevated rpm, the big thumpers become device killers. Ever rode a big 750cc Triumph Bike? No wonder Honda took the laurels with their fours.

rmh

I think we are in a muddle

There is theory then there is present day reality

A multi cylinder four stroker can be un figgen real- Look at Hayabusa and Honda etc..

in our very limited rpm world of small gasoline engines turningpropellers, we are pretty much locked into 8000 rpm tops

and in the 100-200 cc sizes 7000. The twin rules here.

Ever ride a Kow triple two stroke (Z1) from 1970? Beautiful crankshaft design

On the way to the flying field yesterday - I say a yard sale being setup on it was a 1975 Yamaha 175 enduro $150 dollars -complete running no wreck damage I said, I will take it !! then I remembered I can't ride anymore (tin leg). Irang upmy wife and she "bought it"and another flyer immediately ran back and grabbed it. What a deal -even a clean title from 1975.
Anyway if people like the idea of a four - go for it but until something changes in th e world of small airplane engines

My money definately on the twin

awesome

My Feedback: (1)

Anybody ever tried to run a 4cyl 2 stroke on 4 tuned pipes? Wonder if this would even out the stakes power wise? Of course there is the weight disadvantage of four pipes vs two , but with composite pipe technology i am curious how this would compare?

blw

My Feedback: (3)

My dad had two of those monsters. One was stock and the other was the wheelie bar/expansion chamber version. This was the Mach 3, I think. Wasn't the Z1 a 900 4 stroke from around 1974?

rmh

Yes an H1, Mach3 my neighbor had on new then - we stuck a 13 tooth primary sprocket on it to get it to come off the line cleaner.without bogging or spinning hard. I scared myself on that thing -just too easy to go really fast in heartbeat.
That wasthe first bike I ever saw that I thought was too quick for normal street use.
The Hayabusas are simply too much. for any streetriding
And I love power.

blw

My Feedback: (3)

I agree about those bikes being too hot for street use. They had unreal acceleration. You could pull up the front wheel at 70 or 80 by wrapping on just  the throttle alone. 

ARL Model Design

Gents,

How about looking into the Mintor range of engines.

They do a mean peice of kit to say the least..... and, their 220B4 is very good.
they also have all the accessories of which are specifically taylor made for their engines.

Stats as below........

Displacement           220cc

Power:                     23 hp, ((This is genuine only if using Factory Cannister mufflers designed for this engine))

Weight:                    4900 grams

Bore:                        45 mm

Stroke:                     34,6mm

Length:                     208 mm

<place><placename>RPM</placename> <placetype>Range</placetype></place>:             780 - 7000

RPM Max:                8700

8 + 8 petal reed valve ((Configured similar to a pulse jet (Round) intake))

Walbro Carburettor

Warranty: 3 years




Price is pretty good also for what you get.......

I personally have had several of the engines that have been mentioned and find the Mintor engines beat them all in one way or another.....

Very well made and presented peice of kit.

pettit

My Feedback: (23)

Here's a link to a local friend's P-47 with a 3W 212 4 cylinder engine.


It's Cool, and there's a lot to be said for cool.



http://video.google.com/videosearch?...%3Cimg%20src=#

Zeeb

My Feedback: (41)

Didn't notice how old the thread was when I posted.....

ARL Model Design

Gents,

I am aware the thread is a little "old"

However.... how did it end up talking about the Kawasaki Mach 3.....750cc Tripple two stroke.......commonly known as the "Widow Maker"..... for obveous reasons.
There was no suck animal in the 70`s as a Z1....
1974 is the correct year for the introduction of....
Z750
Z750 turbo ((Also arare rocket like the Mach 3 Widow Maker))
Z900 and ....
Z1000

Are we talking about large model aircraft engines on this thread.... or motorcycles????

DKjens

My Feedback: (50)

I don't care what Dick says, how old he is or how much less he doesn't know than me lol. If you take two 2-stroke engines of similar displacement, one a boxer twin, the other a boxer quad, the difference in vibrations is beyond significant. I have an EVO300cc four cylinder on a Bill Hempel 50% Edge540. I can run this engine on the airframe without having wings or stabs mounted, and the vibrations don't kill the airframe (the top of the rudder shakes just enough that you don't want to do this to much), try doing that with a 240-300cc twin.

A quad totally wins in the bling factor, it sounds like a Ferrari, it's throttle responsive, it swings a smaller prop than a similar sized twin, but swings it faster.

For pure reliability, simplicity, power, cost, go with a twin.

For bling, smoothness, stealing the show and if the mechanical technology intriques you, go with the quad.

If you are building a custom lightweight air frame, it will last longer with a quad.

I had a TOC 40% Yak54 with a Herbrandson 280cc twin in it. The engine was converted to reed valve controlled crank case induction with single carburetor (Disk knows it) and is very docile to run and work with. However, after each flight multiple screws were missing, wood joints had to be checked and in general that air frame would not have lasted very long with that engine. It would have been sweet though with the EVO300 and I know a guy in France is flying just that combo.

Jezmo

Dang and I thought it was the ZL900 and ZL1000. Got a friend with a mid eighties ZL900 Eliminator in mint condition, man riding that thing brings back memories. I used to have a Kaw 500 triple, - until I hit a car head on in 1973. Busted more bones than most folks know they have. Memories.