OTS engine restorations, what's okay?

Is this in or against the spirit of OTS competition?

I like vintage engines, but I don't like cantankerous, belligerent or baulky starters. In the majority of cases this can be put down to a worn or out of round and out of tolerance piston sleeve fit, new parts or copies can revitalize performance and starts, so

Is it okay to make new parts out of the same type of materials to get better fits ?

Is it okay to make new parts using the best technology of the period times to improve the running and starting characteristics of a motor?

Orwicks were among the first to use taper in the bores that was later copied by most other manufacturers, is it okay to set up another lapped piston type motor with similar taper in the bore?

Is it okay to resurect original bores with hard chrome plaiting?

Is it okay to use a modern reproduction engine that has been manufactured from newer materials on far better machine tools to far higher tolerances and fits than were typically seen in the late 40's and early 50's

I'm okay with any of the above but wonder if anyone has any thoughts or doubts

Rebuilding an OTS engine would be like having a new one back in the 40's or 50's, so what's the problem? Lots of engines were worked over so they would run sort of consistently. The Fox .35 came along in the late 40's-early 50's and did this with a light weight engine better than most. Others were more powerful, but not lighter. If you ever get the chance to read the older MAN and FM and AT mags from the era, you will find lots of hints and articles on how to make your engine run better. The more things change, the more they remain the same. Only us'ns have gotten older.

LAST EDITED ON Jul-11-04 AT 11:47 AM (CDT)
 
John,

In the USA, engines are not considered for scoring or eligibility. There have been OTS models with the latest Russian or PacRim or Japanese metal (usually) behind the prop. And rebuilt piston-port original sparkers transformed into front rotary valved versions -- (an Ohlsson&Rice 60. O&R built 60s in both forms, too, and similarly to the recent custom conversion I saw.)

I know that in Blighty-proper the pommies get a bit prissy about authenticity - or say they do, anyway. I'd seen lists of score points for details of pedigree for the pieces. Here in the former colonies, OTS is truer to its original intent -- lower stress/easily run event/for models we had -or wished we had- flown when those rules prevailed.

If you want to dissolve a 40-year old dried out tube of Ambroid to make an authentic cement, knock yourself out! You're doing it because that's what you want to do, not because a rule requires it. The only requirement is that the exteriors of the models be the same as the originals, within an average builder's abilities to make it so.

Equal panel All American, Sr? No. Dihedral-winged original presented flat? No. However, I think that one could invert an upright engine on some -- like the early VECO kits which - I think - had scrap sketches both ways on the kit plans.

So, if you have ANYTHING that will turn a prop, us Yanks would welcome you. Many spark entries up here use replicas of engines built as spark-ignited; Russians and CS in the PRChina have built replicas of early diesels... Even the TaiPan himself had done a few replicas, true?

Best answer is find out what goes in the land where you fly...

Not to mention that there are actual reproduction sparkers available, too.

Why dissove an old tube when the stuff is still available? Of course it now has oil of lemon or something so glue sniffers won't use it and the tube is now aluminum vs lead. Too bad about the lead, cause rolled up Ambroid tubes became tip weight. Adjustable my foot. Brass tubes glued to the wing tip with Ambroid were the leadout guides, too.
The Veco "plans" do show several engine installations, ignition, upright, inverted, .60 to .19 for the same plane in some cases.
Any Fox .29 or .35 is OTS legal. Only difference is the muffler lugs, still same old hunk of al you min ium.

>
>Is this in or against the spirit of OTS competition?
>
>I like vintage engines, but I don't like cantankerous,
>belligerent or baulky starters. In the majority of cases
>this can be put down to a worn or out of round and out of
>tolerance piston sleeve fit, new parts or copies can
>revitalize performance and starts, so
>
>Is it okay to make new parts out of the same type of
>materials to get better fits ?
>
>Is it okay to make new parts using the best technology of
>the period times to improve the running and starting
>characteristics of a motor?
>
> Orwicks were among the first to use taper in the bores
>that was later copied by most other manufacturers, is it
>okay to set up another lapped piston type motor with similar
>taper in the bore?
>
>Is it okay to resurect original bores with hard chrome
>plaiting?
>
>Is it okay to use a modern reproduction engine that has been
>manufactured from newer materials on far better machine
>tools to far higher tolerances and fits than were typically
>seen in the late 40's and early 50's
>
>I'm okay with any of the above but wonder if anyone has any
>thoughts or doubts
>
>Cheers John

Ron B.
F4Fguy

These engines were routinely modified or rebuilt at the time.Why should there be any problem with it now? Especially when there is no engine requirement component in the rules(U.S.).I was running chromed McCoys and others in the forties and fifties(legally,as far as I know). Balancing and porting were also routine,as was honing and lapping,and sleeve tapering.I see no reason not to do whatever is needed to get the type of performance these engines were capable of.As to "reproductions",all the kits and plan built planes out there are reproductions.

Incidentally,In my experience,engines of the '30s-'50s were no harder to start or handle than modern ones ,and the ones of equivalent stature lasted just as long or longer when well taken care of.What was true,and remains so today is that are a lot(even more today)who couldn't start and adjust anyengine without help.

I once saw a Taibi "Powerhouse" climbing vertically (R~C), only to find out that the engine was not a hot glow .60, but a GHQ. It had been redesigned and rebuilt by Bill Wisnewski of K&B, for many hundreds of $$$$$. Was it worth it to the owner? I bet it was! And that's ok, both by the rules and by me)! Steve

After looking at what I'd said on the "old time stunt?" topic I thought I might have been seen as getting a bit hypocritical as I've restored a few motors in the past.

When discussing a motor I'd just recently finished with some other modellers a couple of years ago now, it was a 1948 McCoy 36 Sportsman junior that I'd set up with a new piston for a Dykes or "L" ring instead of the standard twin ring set up. One of them became quite vocal about the use of inappropriate technology.
I was quite surprised at such an intense reaction to what I thought was quite a harmless and minor change, and for barely any significant performance increase if any. Certainly if I was to run the motor with a muffler who'd ever know anyway?
but I do like to keep in the spirit of things and I wouldn't have openly discussed it if I'd been looking for some kind of "secret advantage"

Anyway, just thought I'd see if there were any strong feelings about motor restorations for OTS out there, what's okay and what's not? doesn't seem that there are any kind of issues on this one at all which is okay with me.

>After looking at what I'd said on the "old time stunt?"
>topic I thought I might have been seen as getting a bit
>hypocritical as I've restored a few motors in the past.
>
>When discussing a motor I'd just recently finished with some
>other modellers a couple of years ago now, it was a 1948
>McCoy 36 Sportsman junior that I'd set up with a new piston
>for a Dykes or "L" ring instead of the standard twin ring
>set up. One of them became quite vocal about the use of
>inappropriate technology.
>I was quite surprised at such an intense reaction to what I
>thought was quite a harmless and minor change, and for
>barely any significant performance increase if any.
>Certainly if I was to run the motor with a muffler who'd
>ever know anyway?
>but I do like to keep in the spirit of things and I wouldn't
>have openly discussed it if I'd been looking for some kind
>of "secret advantage"
>
>Anyway, just thought I'd see if there were any strong
>feelings about motor restorations for OTS out there, what's
>okay and what's not? doesn't seem that there are any kind of
>issues on this one at all which is okay with me.
>
>Cheers John

Ron B.
F4Fguy

As long as you don't bore and stroke an "Infant" into a GHQ 60.