O&R - Culprit or Victim?!?

[Terry Caron]

This is not to start an argument - I hope merely to open a discussion. If I have a "dog in the fight" it's name is "Truth" so I hope to generate only light, not smoke and fire.
No doubt anyone who's had any interest in O&R engines encountered mention of them blowing the cylinder completely off. I *don't doubt* that it has happened on more than one occasion in the past. But I do wonder about the circumstances.
O&R's assembly process, i.e., essentially spot-welding the cylinder at two points, is clearly weaker than the bolted or threaded assembly as was/is commonly used. It is, however, a sufficiently stout design for it's original FF use, burning a gas/oil mix, and was/still is very successful in that application.

What I wonder is whether their reputed self-destructive propensity is perhaps due solely to the use in earlier days of high-nitro (up to 70%, possibly more) glow fuel in the more demanding arena of c/l flying. There were certainly those who chased after maximum performance then, just as now. Given the huge numbers sold, it isn't at all surprising to me that some might blow apart under abuse, nor that some may have survived but in such a weakened state as to blow apart under completely reasonable conditions more recently. Can a modern engine withstand excessive nitro for long?

Facts and truth are of value in and of themselves and those are my interest here, as it's possible that O&Rs are victims of an undeserved reputation, and so my question:
Has anyone on the forum experienced an O&R blowing it's cylinder off, personally known anyone who has or know of any documented reports of such an incident, under what would be called reasonable use?
If so, would you please post about it, detailing, as much as possible, the engine's history and the circumstances of it's demise?

[phil c]

K&B Green heads are also known for blowing the cylinder off.  Only two screws hold it on.  Probably most common in racing and combat where more nitro was used.  McCoys used three bolts and never seemed to have a problem.  The latest style of F2D engines are also using separate cylinders with 4 bolts, as did Taipan.

Aside from nitro, at the time there were no inexpensive, effective ways to check spot welds for integrity.  I'd say it's quite likely more than a few bad welds were made.

[Terry Caron]

Phil - certainly a possibility in those last O&R years, with tooling, product pride and QC maybe circling the drain.

Ty - No worries, I wouldn't quote that under any circumstance.  

p.s. - Note no standard K&B Green head caution.

[dennis lipsett]

Old Ignition engine blowing cylinders is not a fable. my best experiences was watching an OK Cub 60 glow converted blow the whole cylinder off into never- never land as in never seen again they went so far and had a majestic trajectory when launched. The cylinder was held on with 2 bolts
Glow ignition puts a lot more pressure in the cylinder and 2 screws or pin welds and questionable metallurgy weren't made to take that at all. Why do you think so many brands started disappearing after 1948. The glow plug appeared on lighter weight engines and better performance than the old sparkers could deliver . There was a time when there were at least 60 engine manufacturers in the USA, or so I've read. Many engines appeared right after WW2 when there was an insatiable demand for engines and you can well assume that a lot of junk was put out there.

[Terry Caron]

I stated up front that I didn't deny the reality, Dennis, and your reminiscence (sans any important details) illustrates my point well, as I'm not aware of a similar common caution to Super .60 owners (Bob Z. is quite fond of 'em) to beware blown cylinders.
I simply question whether O&Rs actually deserve the singular reputation.
I doubt that an Orwick or McCoy sparker would survive much high-nitro fuel either.

[Carl Cisneros]

Terry

I had one back in the mid 80's but it was set up for boat use with parts from Octura.
On gas it was nice and reliable to a fault.
BUT, when I popped the nitro in it, well,lets just say that the cylinder
is somewhere in back bay Biloxi Mississippi. Blew that sucker off
about a good 15 feet or so in to the air.

So, using gas/oil I would say it is a reliable motor,but put nitro in it and be prepared...............

[FLOYD CARTER]

The more common failure of the old O&R engines is the cylinder gasket.  It is assembled under compression as the cylinder is spot welded to the crankcase.  Over time, the gasket shrinks, allowing crankcase pressure to leak.  This gives  unstable running, if at all.  There is no adequate fix, other than removing the spot welds to replace the gasket.  Of course, this requires a way to re-do the spot welds.  The late George Tallent, of AZ did this for many customers.  I know of no one able to do this nowadays.

I have temporarily repaired these gaskets by saturating the gasket with epoxy.  Not a reliable or permanent solution.

Floyd

[Terry Caron]

Thanks for relating your experience, Carl.
Do you recall the glow fuel that did the deed?

The loss of Mr. Tallent was a sore blow indeed, Floyd.
Andrew Tinsley has told me of some (perhaps minor) success at O&R cylinder repair and, IIRC, a year or two ago either Leonard Neumann or Bill Mohrbacher at least considered a stab at it 'though I don't know if any progress has been made.

[Brett Buck]

Back in 1972, I knew a guy that sold me an O&R .60. He told me he heard from a guy, whose cousin heard from a friend that he thinks he read it some where that some one had said it had happened to a friends engine, but don't quote me.

     I blew the jug off an Olhsson 23 sideport using Cox racing fuel with ether, trying to keep it running with the battery disconnected.

     Brett

[Terry Caron]

     I blew the jug off an Olhsson 23 sideport using Cox racing fuel with ether, trying to keep it running with the battery disconnected.

     Brett

So that would've been 30% nitro + ether? 
Arguably not "reasonable use", wouldn't you agree?

[Brett Buck]

So that would've been 30% nitro + ether?  
Arguably not "reasonable use", wouldn't you agree?

   Well, given that it wouldn't keep running at all on any lesser mixture, unless you define "normal use" as lying in a drawer rusting, it doesn't work at all.

     It was an ignition engine designed to chug around at 5000 rpm one gasoline/oil. It was probably reliable enough in that application.

     Brett

[Terry Caron]

Well, I wouldn't consider either of those options as normal, so I'd put that one in the "Victim" column.

[john e. holliday]

All this reminded me of when Bob Oge decided to see how much nitro his Rat Racer would take.  I think he said it was over 70% nitro before it blew up.  He was showing us what pieces they could find.  I don't think they enough laps for a speed timing.

[Brett Buck]

Well, I wouldn't consider either of those options as normal, so I'd put that one in the "Victim" column.

      I don't think anyone would disagree that it was adequate for the originally designed purpose, a very weak 30's style ignition engine. It was not up to the task for glow (the original popular glow fuel had 37.5% nitromethane, and about 10% ether) and that blew it up with some regularity. They arrived at the glow fuel formula trying to get equivalently junky and weak ignition engines to run, since, to begin with, there was no such thing as a glow engine. That's why the dedicated glow engines and the very-high-performance racing ignition engines (like the McCoy airplane/tether car engines) worked, and the old Ohlsson, Brown Jr. type engines did not.

    BTW, the other hallmark characteristic of the sideport engines was that they didn't care about which way they ran. It was *much worse* on glow because you at least had some way to control the direction on ignition, and on glow, there was nothing that gave it any preference

     Brett

[Terry Caron]

I'd certainly agree, then, that for the early glow formula the desing was too weak, but should the condemnation still haunt them?
I recently sold 2 .23 FRVs, one ignition, both of which turned a 9-5 APC at 10K+ on 75/25 FAI-type glow fuel and my .60 FRV ignition turns a 13-6 MA at 10.4K on 2:1 meth/castor - not up to modern standards but not really wimpy.
My point is that they perform well with proper and reasonable handling and aren't *uniquely* susceptible to self-destruction unless abused - pretty much like any engine.
 

[FLOYD CARTER]

Remember that Ohlsson & Rice sold many thousands of .29 and .33 glo engines beginning about 1949. These were built exactly the same as their older spark ignition engines, with the spot welded cylinders, and all.  They ran just fine on the commercially available glo fuels of the day. Only when used with exotic fuels with high nitro did they wear out or explode.

Floyd

[Terry Caron]

...Only when used with exotic fuels with high nitro did they wear out or explode.
(snip)
Floyd

Just as I have thought, Floyd - much more a matter of user abuse than design deficiency.
Remindful of "It's the poor workman who blames his tools".

[FLOYD CARTER]

I should have also mentioned that the O&R 60 is a different animal.  Cylinder pressures in the .60 are much higher than the smaller O&R engines.  Therefore, it IS POSSIBLE to blow the cylinder on the .60 running on glo.

Floyd