O&R .23 FRV glow - how fragile?

[Terry Caron]

Hi all -

I received my *Bay buy yesterday,
I disassembled it, gave it a good cleaning and everything looked ok (after I put the piston in the right way!), oiled it up a bit and admired it.

This morning, couldn't stand it, so I installed a 9x6 APC and mounted it on the bench.
Not having any FAI fuel, I used 9% nitro doctored to ~26% (10% castor) oil.
Several drops of prime, a couple flips, connect the battery, 2-3 flips.........it fired off the prime.
I was so amazed that I did that a few more times and it started every time with 2-3 flips.
I hooked up a tank and fired it a few times to get a running needle setting.
At about 3 turns on the needle it was sounding pretty good, so I tached it.
With no further tweaking, it was bumping 10K!
I doubled and tripled check that, then pinched it off.
Now, I think that's pretty good for a wimpy '54ish cross-scavenged O&R .23 and I have no desire to damage it - I LIKE it!

While waiting for the auction to end, I Googled everything I could find on O&Rs and a repeated comment was about cylinders blowing off.
An early undated review on the "new" .23 FRV, without fuel/prop details, noted 8900 with a 9x6.

So my question (after the race, of course  ) for those of you familiar with O&Rs is, are they so fragile that 9% is a real risk?

Terry
 

[Randy Ryan]

Terry, my personal opinion is that you're at the upper limit. These engines indeed have had the cylinders blown out but there were and still are many thousands of them running. Granted they are mostly the sparky persuasion but still, many were run glow after a life as sparkers. Ohlsons are gems considering their vintage, the die castings are light to the extreme. Most were excellent runners though not real power makers, and were the staple of FFers into the 50s. Just keep the oil content up and run ion 5% and you should be able to run it a good long time.

By the way, their major weak point is the main bearing. It is very short and wears rapidly, I've replaced many of them while the rest of the engine were still pristine.

[Terry Caron]

Thanks for posting Randy.
Understand that I wasn't trying to see what I could get out of it, that's just what it gave me right out of the gate!
I'm old enough to appreciate the old-tech engines for what they are and not try to emulate a modern schneurle with 'em.

The LHS will order no-nitro fuel - takes a while though.
Am I right in thinking nitro as such isn't the problem, just trying to run it maxed out?
It's such a pleasure to run I'll richen it some if it's in any danger.
I guess the 8900 reported should be safe, right?

Terry

[Randy Ryan]

Thanks for posting Randy.
Understand that I wasn't trying to see what I could get out of it, that's just what it gave me right out of the gate!
I'm old enough to appreciate the old-tech engines for what they are and not try to emulate a modern schneurle with 'em.

The LHS will order no-nitro fuel - takes a while though.
Am I right in thinking nitro as such isn't the problem, just trying to run it maxed out?
It's such a pleasure to run I'll richen it some if it's in any danger.
I guess the 8900 reported should be safe, right?

Terry

You may fine it completely unhappy without some nitro. And yes I understand what you meant.

[Jim Kraft]

I fly an Ohlsson 23 sideport on spark on an old Free Flight Lanzo Bomber that is scaled down to 60" and it is amazing how it will turn a 12-4 Top Flite Power prop. I think the Ohlsson 23 was the best of all of the small Ohlssons. I also believe they were the least prone to blowing the cyl. off. Sounds like you got a really good one. As Randy says, they do have very thin cases and short crank bearings, but they do run a long time if not crashed on concrete. Even after the crank bearing is loose they still run good. I have a small port 60 that is very loose but will turn an APC 13-4 at 9300 on alky fuel.

[Terry Caron]

Thanks guys.
I don't know the prop range for this engine, so went with the old review's selection.
Am I maybe under-propped?

Terry

[Jim Kraft]

I think you are pretty close with a 9-6, but you might also want to try a 10-6. It will depend a lot on the plane you are trying to fly with it. I would keep the pitch up to at least 6 though, and go from there. Sure would not hurt to try a 5 pitch, but I think you will like the 6 better for control line.

[Terry Caron]

I don't have a plane for it yet, just playing on the bench right now.
Sure thinking about something period for it though.
What's a good wing area for it?
 
I tried running it a bit richer and it didn't like that at all.
I leaned it back out and tached it while pinching it off and it came up another 2K or more as it quit.
I'm still way down on the learning curve - I've flown only rubber FF for years - so would a larger prop allow me to safely run it leaned more?

Randy - if I came across as snippy, please accept my apology - it was completely unintentional.
I meant only to convey my appreciation for fine old engines.

Terry

[Randy Ryan]

I don't have a plane for it yet, just playing on the bench right now.
Sure thinking about something period for it though.
What's a good wing area for it?
 
I tried running it a bit richer and it didn't like that at all.
I leaned it back out and tached it while pinching it off and it came up another 2K or more as it quit.
I'm still way down on the learning curve - I've flown only rubber FF for years - so would a larger prop allow me to safely run it leaned more?

Randy - if I came across as snippy, please accept my apology - it was completely unintentional.
I meant only to convey my appreciation for fine old engines.

Terry

Not in the least Terry, forum talk is good but you can see faces, that's why things get ugly sometimes, I try to never let it effect me unless it gets personal. Glad to hear you're an old rubber flyer, so am I. Actually I've flown every thing except choppers which hold little interest for me. I still do fly FF power and rubber. Jim is right on with his prop comments and the loose bearings aren't a really big deal unless you're anal like me and want them to fit correctly. In reality the only time it really causes trouble is on a sparker because it blows oil out onto the points.

[Terry Caron]

Thanks Randy.

So what'd be considered a high, safe top rpm figure for 9x6 and 10x6 props?

Terry