Strange OS .35

Here’s one for you OS experts.
My friend found this engine and gave it to me
It’s a Max – H 35.
The case appears identical to the .40.
It’s not the combat special.
Dual ball bearings and a lapped baffle piston.
Two venturis, looking very much as intended for stunt.
It has two sets of instructions, one in English, one in Japanese.
New in the box, never run.
I will break it in with the fuel as suggested in the instructions – 5% nitro, 25% castor.
Are any of you familiar with it?
Bob Z.

Looks like the one I had back in the late'60s/early '70s. It was a great engine, but it got lost in one of our many moves (military). Is the exhaust flange tapped to accept a muffler? As I recall, mine wasn't, as mufflers weren't a big deal back then.
Anyway, you've got a jewel there.
Glen

No mystery at all, Z man...

Google OS History.

Then, click on Manufacturing Timeline.

Click on 1966-1968.

You will find it there.

"Every" motor OS ever did is right there. One thing I like about the OS pics is that some of the motors are not new.

Question: Your Scientific Hollow Log Bullet had hidden leadouts, right? How did you do it? Did you use two sheets for the wings, make grooves, and glue them together? Or...?

Z: Also note that there was an RC version, too. Currell

Glen: As you can see in the OS website pic, it used a strap-on muffer.

>Glen: As you can see in the OS website pic, it used a
>strap-on muffer.
>
>Currell

Yes, but...

This engine, like the 35S, has a wide enough exhaust stack that if you carefully drill from the back side--in this case on the flat area in the back area of the exhaust stack--and center the drill bit as if it were in the center point of the arc that forms the outside edge, you can then use a bolt on muffler which has the same spacing as the 25 FP. Drill this on a drill press with the exhaust aiming down and do drill from the back side. Some people have tried to drill from the exhaust side and end up getting the holes crooked. They also end up getting shavings in the exhaust that way. You don't need to be perfect when you do this, but make the holes only as big as needed for 4-40 bolts.

Then use a good tongue muffler and save weight.

Of course, if it is new in box, I might opt to keep it as a collector.

Hi, Currell.

Interesting question. The driving idea was to get the entire control system inside the plane.

I made the wing in one piece from lightweight balsa. Then I cut out a section on the inboard side. The width of the section corresponded to the leadout span and position at the center and tip.

Then, I designed and built a miniature milling machine to cut the groove. I then cut grooves in the front and rear edges of the piece I cut out of the wing.

After cutting the .025 high x .030 wide grooves, I glued the piece back into the wing. It was done very carefully so as not to block the grooves with glue.

I molded a little bellcrank from carbon fiber and installed a Teflon bushing. Attached some .012 leadouts and fed them out through the grooves I made. I put little pieces of Teflon tube to act as guides.

The wing is covered with silk for strength.

A bit of work? Yes – but, the look on Walt’s face when he saw it made it worth every minute.

Wait till you see next year’s plane.

LAST EDITED ON Oct-13-04 AT 08:44 PM (CDT)
 
Currell,

I tried your search and popped up a bunch of links to information about the history of various computer Operating Systems, mostly Mac. I've tried with and without "quotes" with the same result. The only sites I've found that show any OS Max histroy show about eight engines, i.e., those considered to be major milestones. None have a manufacturing timeline link.

I really would like to find the site to which you refer. Any further help that you can provide would be greatly appreciated.

Thanks.

http://www.osengines.com/history.html
Pat MacKenzie

Doh! I totally missed the link at the top of that page.

Thanks, Pat.

>
>"Every" motor OS ever did is right there.
>
>Currell

Wrong!

OS made a copy of the ED Bee. Not a common engine, but no reason to omit it from the history sheets.

cheers, Dave

Here's another that isn't shown in the timeline pages. The Max II on the left is shown but the Max II on the right isn't. There's an obvious difference in the crankcase but it also uses the larger crankshaft and drive washer as in the Max III's. Maybe it should be called a Max II.V

It appears the timeline pages were put together by someone from the OS agents (Hobbico) by borrowing every example they could find, in which case they did a very good job.

>>
>>"Every" motor OS ever did is right there.
>>
>>Currell
>
>Wrong!
>
>OS made a copy of the ED Bee. Not a common engine, but no
>reason to omit it from the history sheets.
>
>cheers, Dave

by any act, error, or omission, I have, intentionally or
unintentionally, displayed any breedist, disciplinist, sexist, racist,
culturalist, nationalist, regionalist, localist, ageist, lookist, ableist,
sizeist, speciesist, intellectualist, socioeconomicist, ethnocentrist,
phallocentrist, heteropatriarchalist, or other violation of the rules of
political correctness, known or unknown, I am not sorry and I encourage you
to get over it.

They also made a 15 diesel that had 360 porting and front induction. The cylinder was anodized blue. I had one but it was 'appropriated' some 15 years ago. Can't find any reference to it anywhere. The Max3 type diesel is of course well known.
Dennis

Bob,

I have one that looks just like yours and it is plain bearing front end. I have a bunch of the 40-H and just one of them is a bronze front end. The crank case looks the same on the plain and BB 40-H the difference externally is the thrust washer on the BB has a groove around it that makes it look a little like a pully. The strap on muffler for the 40 will fit the 35.

Possibly you should look very closely at the front end. The prop driver looks very thin for the 2BB engine. These engines look like 2BB, but have you checked for sure there is a bearing in there?

My H-35 combat specials look exactly like that. They came with both a suction and pressure venturi inserts and the pressure fitting. The combat specials do not have a front bearing either.

Hey Bob!

Thats a nice OS Max! If you don't want it I'll trade ya something for it, no problem!

Doncha just love gifts like that?

Hi Bob.

I had the throttled version (a big butterfly thing) from when my dad had it mounted on a profile Neuport with 3-line control way back when.

I heard they were honkers, and gave it to my brother to fly FF with (he's pretty serious about FF). And it is indeed a honker. Hard to believe his RPM numbers, but he only flys it a few seconds at a time. This is with a bladder, no venturi insert, and itty-bitty props with beacoup nitro. Some old time event where your plane has to weigh the same number of ounces as the displacement of the mill. It interchanges on the same plane with a .29 version. Which I also scored for him at the Lebanon swap meet, actually. #####, I'm a nice guy, eh?

At least it isn't just sitting around gathering dust.

The carb is (gathering dust), if anyone's interested. I'll trade it for a nice like-new ST 46 or maybe a nice big box of rocks.

But, they'd better be nice ones (rocks, that is). Seems all the boxes of rocks I talk to are just run of the mill boxes of rocks.

I'm looking for something a little more astute.

Clayton...sorry to hear that your bid failed.
Where is the line to experience the random acts?

See Ya

Further thoughts on this Bob - If it's n.i.b. what does it say on the box?

Hi, Ian - check out the picture of the box.
By the way, this is not the OS combat special. I have one of those and it's marked "CS" on the case.
Bob Z

>Here’s one for you OS experts.
>My friend found this engine and gave it to me
>It’s a Max – H 35.
>The case appears identical to the .40.
>It’s not the combat special.
>Dual ball bearings and a lapped baffle piston.
>Two venturis, looking very much as intended for stunt.
>It has two sets of instructions, one in English, one in
>Japanese.
>New in the box, never run.
>I will break it in with the fuel as suggested in the
>instructions – 5% nitro, 25% castor.
>Are any of you familiar with it?
>Bob Z.

I remember when these engines came out. They were a promising upgrade from the OS MAX III's that many of us were using.

Unfortunately for OS, the SuperTigre 35C and G21/35 hit the market at the same time and totally blew OS out of the comabt market --- FOR GOOD.