"OS 4O/45 FSR's" long forgotten???

After the great feedback on the "OS46LA v STG51",

One engine that comes to mind is the "OS40/45 fsr"
series, granted these motors are long out of production
now, but even the R/C guy's know how "good" these motors
actully are! with top NIB's pulling $ on the bay.
Though there are many of these around "why" is it that
so few use these for C/L stunt?

Sure they are not light but they would,nt be that far
off a current STG51 for weight any how I'd guess.
Is the main reason for the "FSR's" unpopularity was
the "rework" needed to get them "right" for stunt use.
I have a couple of FSRs R/C versions but I would dearly
love to use them for Stunt if I could find the right re-work
guy?

rny.

LAST EDITED ON Dec-28-03 AT 11:37 PM (CDT)
 
RNY,
You might try Tom Muggleton. He did 2 of them for me. He only likes to work on them if there new. Don't worry about the weight as they haul their own freight with no problem.

For a while, OS FSR-S (as stock, with spraybar/venturii in lieu RC carb)engines were available. I used a 40FSR-S stock out of the box, with per instructions bench break-in, for many hundreds of flights in one model. Ran great; preferred low-2 setting on flattish pitch/large diameter prop.

Apparently, the RC versions had different shaft, and possibly sleeve, timing. My FSR-S had a lot of grunt on about a 13D, 4P prop carved from a Zinger 'prop blank'. Very thin blades seemed to make it happiest. We didn't have Bolly, Eather or some of the "custom" APCs back then...

Very reliable starting, but after about 400 flights it didn't bump during starting drill -- just started if you took all the right prep steps. Still in good condition; may hang another plane on it...

I seem to recall an odd "tank height" to get it even both ways, but once there, solid and reliable.

One problem was the fragile rings. I never had a problem with the RC planes, but I guess the cowling on many CL stunters caused hotter runs.

The only other thing I can think of is that most of the top fliers just went to rear exhaust engines and ran pipes in the early 1990's.

Ron King

Darn good engine. I likes em myself. I have had venturi's made for some of mine by [email protected] He does a very good job on them.

Bill

Hi Crash,

This venturi guy, are his venturi's alloy
or delrin ??

*PS* I too would have flown "balls out" today
as it was over the 100o very hotttttt!!

Good flying!!

rny, his venturi's are all alloy and made on a CNC machine. Very accurate. Where was it over 100 today?

Bill

Hey thanks Bill !

Sorry for the late reply, it was over the 100o
mark here a little while ago.
Where? Melbourne >>AUSTRALIA.

Happy New Year!

rny:)

I have never had a problem with the rings on these motors. But I run the traditional 2-4 break. Which means not a piped lean max RPM like PW. Rings are available from Frank Bowman

LAST EDITED ON Dec-30-03 AT 03:07 PM (CDT)
 
*PS* I too would have flown "balls out" today
as it was over the 100o very hotttttt!!

Good flying!!

rny,

I think not. Certainly not if the temperature was as high as you claim.

The phrase "balls out" refers to mechanical governors used on stationary engines way back when. As the engine picked up speed the balls (flyweights) would swing outward, this resulting in various mecanical ways to slow the engine, most common being not allowing the exhaust valve to seat.

A governor adjusted to allow maximum speed from such an engine could be seen to have the balls all the way out, as in they could not swing out any further. Hence, the phrase, "She's running balls out, boys!" or some such, sometimes followed by catastrophic failure of some vital component.

Dan, flying in this manner has also been known to have catistrophic failure of one sort or another usually resulting in the airborn object meeting earth in a rather violent manner.

Bill

>I have never had a problem with the rings on these motors.
>But I run the traditional 2-4 break. Which means not a piped
>lean max RPM like PW. Rings are available from Frank Bowman

Most people running the 40FSR did (or at least tried) 4-2 breaks - and they were absolutely notorious for "wearing out" rings in short order. It was really the Achilles heel of the engine. I wouldn't necessarily expect that running flat-out would make it "wear out" (or whatever it really did) any faster or slower. A lot of ringed engines actually maintained a better seal if you ran them fast with light loads, like in break-in.

In Paul Walker's "IMPACT" article (FM 5-91), he discussed engines he'd used before the OS .40VF. One of those was the OS .40 FSR, but he fitted the piston/cylinder from a .40 FP, with milder timing. And no rings. Implication was that it's a drop in, as I recall. It's a good read, if you can scrounge up a copy. Steve

>In Paul Walker's "IMPACT" article (FM 5-91), he discussed
>engines he'd used before the OS .40VF. One of those was the
>OS .40 FSR, but he fitted the piston/cylinder from a .40 FP,
>with milder timing. And no rings. Implication was that it's
>a drop in, as I recall. It's a good read, if you can
>scrounge up a copy. Steve
>
>http://www.nwskyraiders.com/index.html

It is a drop in fit (in a way) but the timing is essentially the same. You eliminate the ring in the equation. However, the FP uses a floating wrist pin in the piston. The reason the exhaust is angled on FP (and clones) is so the wrist pin does not float over any open ports. It actually rides up and down on the webbing between ports with its teflon pads. When you put this piston/cylinder in the FSR, the wrist pin will float right over the bypass ports. It is inviting a stuck and jammed piston, and a bunch of other damage. Although Paul did (somehow) get it to work, I would not recommend this conversion.

>the FP uses a floating wrist pin in the piston. The reason
>the exhaust is angled on FP (and clones) is so the wrist pin
>does not float over any open ports. It actually rides up
>and down on the webbing between ports with its teflon pads.
>When you put this piston/cylinder in the FSR, the wrist pin
>will float right over the bypass ports. It is inviting a
>stuck and jammed piston, and a bunch of other damage.
>Although Paul did (somehow) get it to work, I would not
>recommend this conversion.

There is a quick and dirty way to cut a wrispin clip groove in a piston. The cutter for this operation is the small engraving tool that comes with the Dremel Tool. Tack glue the wristpin or a drill rod in the piston, leaving enough space for the groove and a little clearance for the engraving tool. Using the end of the pin for a guide/stop cut a groove with the engraving tool in the dremel, As always, practice something like this on a old junk piston before trying this on a good part ! I have used this way of cutting wristpin grooves on several pistons.

I ran OS 40 FSR motors during the early 80's. I liked the Normal R/C version of the motor better that the C/L version.

Wait a minute. If I use a standard piston pin from an FP40 with the teflon pads, is it necessary to cut the groove? The last time I replaced a piston and cylinder liner in an FP there didn't appear to be a piston groove. I centered the pin and expected the teflon pads to ride over the cylinder liner. So far that's been the case. I have been breaking the new liner and piston in without any problem.

I bring this up because I got an FSR on ebay by mistake. When I opened the package the bearings appeared smooth but the engine promptly spit our broken piston ring. If I can fit a tower 40 piston and cylinder, using a tower piston pin, I could be in business. Will that work without cutting any groove? Not about to do that.

Thanx

>Wait a minute. If I use a standard piston pin from an FP40
>with the teflon pads, is it necessary to cut the groove? The
>last time I replaced a piston and cylinder liner in an FP
>there didn't appear to be a piston groove. I centered the
>pin and expected the teflon pads to ride over the cylinder
>liner. So far that's been the case. I have been breaking the
>new liner and piston in without any problem.
>
>I bring this up because I got an FSR on ebay by mistake.
>When I opened the package the bearings appeared smooth but
>the engine promptly spit our broken piston ring. If I can
>fit a tower 40 piston and cylinder, using a tower piston
>pin, I could be in business. Will that work without cutting
>any groove? Not about to do that.
>
>Thanx
>
>Dennis

The problem, as I mentioned, is that the FP engine has the cylinder angled at approximately 45 degrees so that the wrist pin rides up and down on the space between the ports. If you put the same piston in the FSR with the cylinder "normal", then the wrist pin will ride over the opening of the ports to the front and the back. This could lead to disaster, which is where the circlip idea comes in (if you do it correctly--not advisable if you have never before tried.) It would be better to simply get a new ring. Cheaper, too.

LAST EDITED ON Dec-31-03 AT 08:15 PM (CDT)
 
Gotcha. Thanks Leonard. Happy New Year!

Just went through the 9 of these engines I have and 4 of those appear to be ABC engines. No rings at all.

Bill

Anybody know if the .40 & .45 FSR use the same case casting? Is the stroke the same? Steve