stunthanger.com

Engine basics => Engine set up tips => Topic started by: charlie on April 12, 2006, 02:40:17 AM

Title: OS Max .40H
Post by: charlie on April 12, 2006, 02:40:17 AM
I have one of these. It is a crossflow (baffle) motor with a ringed aluminium piston. C/L version. Can anyone with experience of these engines tell me how they behave? Are they any use for stunt?
Thanks in advance.

Charlie
Title: Re: OS Max .40H
Post by: Bill Little on April 12, 2006, 06:21:57 AM
I have one of these. It is a crossflow (baffle) motor with a ringed aluminium piston. C/L version. Can anyone with experience of these engines tell me how they behave? Are they any use for stunt?
Thanks in advance.

Charlie

Hi Charlie,
Personally, I have never had a 40H, but there were a lot of people using them in the early '70s.  And some still are.
Title: Re: OS Max .40H
Post by: RandySmith on April 12, 2006, 10:03:04 AM
Hi Charlie

That is one of the best stunt engines OS ever made, many people used them instead of ST 46s.
These were single by pass motors, with a baffled piston.
A 23 %  1/2 castor  1/2  syn.  works  very well in the motor.
If you run the motor in a nice rich 4-2  it will last a long time and give you many 100s flights
They have good power, a friend of mine flew a 630 sq in plane with his, with no problem. It would have pulled a larger one.
This would be a good engine for most ST 46 size  airplanes

Regards
Randy
Title: Re: OS Max .40H
Post by: charlie on April 12, 2006, 06:17:23 PM
That is what I wanted to know.  Thanks very much for the help.
Title: Re: OS Max .40H
Post by: rustler on April 14, 2006, 08:47:58 AM
Hoping I've got this right - It's worth remembering there are quite a few 40 motors with MAX-H on the side. For starters there are two basic configs. with different bores and strokes. The narrow bore ones are all lapped and single ballrace (I believe) and the large bores are ringed and double BB. Narrow bores come in at least R/C and RR versions, RR being Rat Race! This does not make a good stunt engine, but the R/C is pretty good for stunt? Don't know if any were put out as stricly C/L. R/C and RR appear in a little circle on the c/case somewhere.
The large bores were available in R/C and I don't know what else, but they were double BB and in the search for more power for the R/C boys, they became a little less friendly for stunt.
Title: Re: OS Max .40H
Post by: RandySmith on April 14, 2006, 12:46:49 PM
Hi Charlie

The  ones I have here have MAX-H on the crankcase with OS under it.
It is a 1 piece case with dual ball bearings
The have a Steel liner, Alum baffled piston, with a ring
They have 4207  MADE IN JAPAN on the back plate and most, but not all have  KA stamped ubder the motor lug
They take the same  muffler as the  35S bolt on

These  are the ones that ran very well for us

A REV-UP  11 x 5 w  was  a good  prop for them.  There are  many  good props today

Hope this helps

Randy
Title: Re: OS Max .40H
Post by: charlie on April 15, 2006, 07:56:42 AM
Thanks Randy,  that description fits the engine that I have exactly with the exception of the marking under the engine lug.
Title: Re: OS Max .40H
Post by: YakNine on July 28, 2010, 12:38:26 PM
Randy do you sell a venturi for this engine I have a .40 R/C engine that I have never run and would like to convert it for C/L . Thanks T.J.
Title: Re: OS Max .40H
Post by: RandySmith on July 28, 2010, 01:07:46 PM
Randy do you sell a venturi for this engine I have a .40 R/C engine that I have never run and would like to convert it for C/L . Thanks T.J.

Hi

Yes I can make those for you plus I have the NVAs that work that are PA style

Randy
Title: Re: OS Max .40H
Post by: YakNine on July 28, 2010, 05:38:51 PM
Do you want the engine sent to you for dimensions to verify fit ? Its not a problem UPS comes to my shop every day. Thanks T.J.