OS MAX-1 .35

Does anyone have any experience with this engine? I bought a Steerling Yak on the bay awhile back and it had one of these engines mounted on it.
I checked the OS time line and it looks like it came out in 1954.
It has the original needle valve assy (the one with the little spring tensioner and curved fuel nipple) and the rubber exhaust and venturi plugs.
There is a boss on the side with the numbers 1798 stamped on it
The prop washer has six little hex head bolts cast into it.
It looks like it's in good shape, nothing is broken or chipped. It's a little stiff, so I didn't force it or "do" anything to it. I would imagine that gaskets and screws would be hard to find.
Any parts sources for these? OS Literature? Some suggestions for a model that came out around the same time would be helpful also.
It's a neat little engine and I'd like to build something worthy around it.

Thanks in advance

This one from 1954?

I bought one of the early ones brought in by World Engines. I used it for combat and it was at least equal in power to the Green Head K&B which was top dog at the time. Great motor! Should be good for "Classic" size stunters. I've got one I bought on eBay that will go into a Barnstormer.
Steve
The older I get, the better I used to fly!

LAST EDITED ON Nov-29-04 AT 03:29 AM (CST)
 
>I bought one of the early ones brought in by World Engines.
>I used it for combat and it was at least equal in power to
>the Green Head K&B which was top dog at the time. Great
>motor! Should be good for "Classic" size stunters. I've
>got one I bought on eBay that will go into a Barnstormer.
>Steve
>The older I get, the better I used to fly!

Hi Guys, I don't know about stunt application....but I and several
others used them in sport and combat flying in the middle and late
1950's. I got mine after seeing Jim Hudson's Combat wings
screaming in flight(at least for those days). Again, this was in
the South Bay, Calif area. For some strange reason, his 82-84mph
wings were going the same speed as the 112mph Johnson powered models.
Also, I never saw a MAX-I .35 that didn't have a scorched head...
Tony

>This one from 1954?

Yep, Thats the one.

Never used one, but they have a terrific reputation as a stunt motor. It seems O.S. Max-1 and Max-2 35's had this reputation, but as they sought more power with the Max-3 and beyond, they got less friendly for stunt.
This is a good opportunity to ask - There seems to be a dire shortage of Vintage and Classic Japanese Stunt designs, which could use these motors. Anyone know why, or how this can be remedied?

LAST EDITED ON Nov-28-04 AT 09:58 PM (CST)
 
Right on all counts. Sometime they're referred to as "steel fin"s.

Remember, use lots and lots of real castor oil in the fuel. Be careful on headbolt tension, also.

As I recall, they are sub piston induction so they will not take kindly to a muffler.

For what it's worth, they are very, very prized by free flighters for their Nostalgia classes.

Have fun,

Jeff

EDIT: As to vintage and classic Japanese designs, I don't remember many being around till maybe the later 60's. Lot's of other stuff but not much in stunters. That might be worth starting a fresh thread.

LAST EDITED ON Nov-29-04 AT 03:57 AM (CST)
 
I have an OS-Max 35 that has no number after it - I think it's one of what's called the Combatniks - any more info?

Or did all -II's not have the number cast on the case?

Tony

As I recall, Max II was never marked on the castings. There were 2 versions, one with a small crank like the Max I and the "Combatnik" with a bigger shaft and inlet so lots more power. The Max III got the shiney case and similar configuration to the Combatnik.
Steve
The older I get, the better I used to fly!

I bought one of these in 1957 and used it for many years. I still have it, but it doesn't run well because it's been thumped into tarmac one time too many. Mine had a tendency to run away when it got hot. Most of my models in those days didn't have good cooling anyway. The original needle works fine if you remove that spring, otherwise it will moe in flight due to vibration.

LAST EDITED ON Nov-29-04 AT 08:02 PM (CST)
 
I've got two versions of the Max-II's (a small crank and a large crank) and neither of them have the II on the crankcase.

Just edited to add a photo. The small crank is on the left and the differences are fairly obvious.

Hi John,
Contact me offline with an address. I have a gasket set for you.
regards
Dave Owen

>Hi John,
>Contact me offline with an address. I have a gasket set for
>you.
>regards
>Dave Owen

Dave, I received the gasket set. Thank You Very Much.
If there s anything that you need from the states let me know.

Thanks Again,
John Jolley

Can anyone post a copy of the Combatnik - or are all of the large crank -II's Combatniks?

Tony

LAST EDITED ON Dec-01-04 AT 09:03 AM (CST)
 
World Engines who was the US distributor for OS at the time used the "Combtnik" term in its ads for the large crank Max II 35 since there was no marking difference on the engine itself. This was a takoff on the first Russian sattelite called Sputnik. It looked identical to the 29 in the earlier picture. Took forever to break-in, but put out lots of power for the time.
Steve
The older I get, the better I used to fly!

Darn good motors. Use plenty of castor in the fuel and, if your specimen is new, it may take LOTS of breaking in. Sometimes it'd be necessary to run a gallon or so of fuel through the early ones before they'd hold a lean setting for a whole run.

Lorenzo Cordova