Conference vmszoo::rc

    
    	That is an OS .40 FSR.  You will love that engine!  They start
    easy and have plenty of power, more than enough for your PT40.  Just
    run it rich and it will last forever...  Do remember to burn out any
    remaining fuel and oil it at the end of the flying day to keep the
    ball bearings happy.

    	Enjoy.  You've got a near top-of-the-line engine there.

Hi Chris,

The OS40SR is a bit of a collectors item. It would be probably 12-15 years old, 
it has a rear drum valve intake with as I recall side exhaust. The timing is 
quite whiled (approx 172�) which does not lend itself to a sport model. Most of 
the engines were run with a venturie rather than a carburetor giving two speeds 
GOoooo and stop. It is schneurle ported ABC engine.

I used to run one on straight 4:1 fuel (no Nitro) on a 7 3/4 X 6 prop at around 
19,000 on the deck, it would unload in the air to around 24-25,000; not real 
good by todays standard but good for those days.

In its time it was a very competitive engine, the back plates are still a 
sought after item as they fit a number of present day racing engines (STX, K&B, 
Etc).

My advice is don't use it on a sport model for learning to fly, it will probably 
be too quick. Get a standard OS45FSR or similar, it is much easier to handle.

John.

    	In response to .3, my 40FSRs only have the `SR' stamped on the
    case.  Does that mean I have some of the oldies?  It isn't ABC for
    sure...
    
    	Tonight I'll check the carburetor number and the muffler number
    and ask again.

    
    	Checked my engines.  The carb number is 4BK and the muffler
    number is 743.  I'm willing to bet is is the newer .40FSR and not
    an oldie...
    
    	Enjoy.

    Thanks for the input.  I suspected that what I have is a .40 FSR.
    I also have the 4BK carb and No. 743 muffler.  It is definitely
    not ABC (it has a single piston ring, No rings in ABC right?)
    
    It appears to be the right engine for my PT40.  I watched several
    planes at the local air field and the PT40 looks like a great choice
    for a beginner.  It does not move very fast but can do some aerobatic
    flying.  My buddy just had his first lesson yesterday with his T.T.
    Skylark 40S.  It's fast with a T.T. .45. He flew about 30 seconds
    the first time and it took him an hour to stop shaking.  He said
    it was exhilarating.  Boy, I can't wait to fly my PT40.  Got the wing
    built and it's almost ready to cover. I was told by some of the
    local experts that Black Baron is a good covering material.  Any
    comments.  Now, if my wife will just let me get my radio out of lay
    away.....!
    
    Thanks for the help,
    
    Chris Spohr
    
    
    

    CHRIS,
    Personally I love controversy. I think we earn more in a lost argument
    than in a three week training course. 
    
    Therefore I suggest you read note 238.

I picked up an OS engine yesterday and need help to identify it.
It is a .25, with no other designation on the crankcase.

Its carb is marked 2B and it has the idle mixture screw in the
center of the throttle arm, versus having it on the carb body. 
The throttle appears to be of the sliding barrel type, as in
Super Tigre or Fox engines.

When you look into the exhaust port, it has a bend for the
gasses; that is, the exhaust comes out of the port and makes a
little bend before going straight into the muffler -- presumably
to give it a little more swirl?

It appears to be Schnuerle ported and ABC, though I won't swear
to it.

The shyster that sold it said its an FSR, but of course it can't
be since there is no .25 FSR.  I suspect its an FP.  Whatcha
think?

    OS _does_ make a .25 sized ball bearing engine and I think it's
    called a .25 FSR.  That may be what you have after all...

    The OS .25 FP does not have ball bearings.  Worse comes to worse,
    take it apart and look...

                                - Dan

John,
the old high end OS .25 was the OS .25 FSR. That's now been replaced by the 
OS .25 SF. The low end .25 is the OS .25 FP. Tower just had a clearence sale
listing the OS .25 FSR for $44.00. The going price for an OS .25 FP is around
$54 and the OS .25 SF is way up there.

Naturaly, when I called Tower, they had already sold out of the .25 FSR, but 
that's another note. 8^)

OK thanks Dan(s).  I looked in the '89 Tower catalog and there it
was, the .25 FSR.  Looks like the same engine as the current SF,
except that it weighs 7.6 oz and the FSR weighs 9 oz.  Its in a
plane now, but if it really bugs me I can weigh them to tell the
difference.

Now that I look at the pictures a little closer, it appears that
the fin pattern on the SF is more like my engine.  It has shallow
fins down down part way into the into the crankcase, while on the
FSR the fins are deep high on the head, with no shallow ones. 

    re .7
    
    Well, I own an OS .25 FSR, they do exist.
    
    The FP has no ball bearing, the FSR does. Look at the front
    of the crankshaft housing. If it is narrow right back to the
    crankcase, without room for a ball bearing, it's an FP. I'll
    check when I get home, but I think the FSR comes apart in
    front of the crankcase (you can remove the shaft/bearing/carb
    assembly from the front of the engine), while the FP has a
    one-piece cast block.
    
    If you're still mystified, I'll bring in my .25 FSR and
    describe it in detail - it's currently not mounted in an
    airplane (a condition I hope to remedy real soon). But, whatever
    it is, it ought to be a good running engine if it's an OS.
    
    Dave

Thanks Dave.  Actually, I never had a question that it was an FP;
I didn't know if it is an SF or FSR.  I looked at it last nite
and I can positively say its an FSR -- I would've liked to have
had the SF instead, but no big deal (the FSR is a little heavy
since I tend to build tails light).  Last nite I fired it up and
got a solid 11.3K with a 9-6; good enough for government work,
and I think its not fully broken in yet.

My expert says I should be swinging a 9-4 at close to 13K and I'm
going to try it, but to be honest that kind of revs on the ground
is out of my comfort zone.  Your opinion is very welcome, and
what are you swinging with yours?

While you're on the line, I notice tht the .25 was offered as
both the .25 FSR and the .25 F ABC in the FSR series (Tower 1989
catalog).  Any easy to tell the difference, or is it the ol'
look-in-the-exhaust-port-and-see-if-its-shiny routine?

    I would use a 9/6 on a 25FSR. A 9/4 is more for a wimpy 20 0r 25FP. 
    You might get more revs and noise with the 9/4 but you'll go better
    with the 9/6.
    
    Charlie
    

    I use a 9-6 on my .25 FSR. By the way, I looked over my motor
    last night and I was wrong - the front of the crankcase is
    not removable. It does have the carb with the idle mixture
    screw in the middle of the throttle horn.
    
    Dave

OK.  I'm going to keep the 9-6 APC on it, but will try the 9-4
later, since it would be dumb to dismiss the advice.

I've been having trouble getting a good peak on the needle valve,
and last nite I took the carb apart to look at it.  I think that
the two O rings on the sliding part of the valve are not seating
properly. Gonna check with Phlyin' Phil this morn to see if I can
get some new ones, meanwhile I've bolted the carb from my OS
.40FP onto the little hummer.

Sure is a nice engine, starts with a hand flip, and runs very
well.

Couldn't fly this weekend, besides being tied up with family
stuff, the wind blew hard the whole time.  Woke up this morning
and it was perfect outside, so I figured it was time to go back
to work. :-(

    
    (Damn, got to re-type this due to network failure!)
    
    So, another "mystery engine" for the panel.
    
    I've recently acquired an old diesel engine (there goes half the
    audience), which I'd like some help to identify. The crankcase is
    marked "Allbon", and "Made in England". I've worked the capacity out to
    be in the order of 0.033 cu in, but this is based on rough measurements
    and schoolboy maths (knew that stuff would come in handy one day!).
    
    So if anyone can help with a rather aged English diesel, I'd be very
    grateful. 
    
    Hmmm..... Old..... English....... Sounds like a job for the Evil
    one!!!!  8^)
    
    Cheers
    
    Nigel
    
    

    Beats me!.
    
    There was DC, Davies Charlton Albion .75cc?.
    
    E.

    
    I was at a swap meet the other day (great deals! Cox .049 in it's box
    never run, 8 quid!).
    
    A guy there identified my engine as an 1953 Allbon "Green Head", worth
    about 50 pounds. Since I paid 25 for it, in a plane I am now a happy
    boy! 8^)
    
    It needs a slight repair to one mounting lug. Anyone know of a place to
    get this done in the UK?
    
    Cheers
    
    Nigel