Hi Combat folks. Wich was the best combat engine at the time, ST G 21/35, Fox 36 X, Johnson 36 CS or ST C 35?
Wich was more powerful or better ?
The OS 35 III were used in AMA fast combat? and about the Enya 35?
The ST G 21 35 Mk II (PDP) catch up in fast combat at the time??
thanks by answering
Carlo

Fox:  The needle bearing Fox Combat Special, which sold for $20 circa 1960 was a real winner.  The less expenive Foxes, (X, Rocket, etc) were generally junk.
The OS Max III, which sold for about $12.95 was a popular and powerful engine.  Hot starts were a challenge, but in fast combat, not much of an issue.
JOHNSONS:  The JCS at $20 and the JBB at $25 were first choice for those who could afford to buy one engine for the price of two.  Riley Wooten's engine of choice.

Thank you so much Paul, by the very clear and complete explanations 
Regards
Carlo

Dont forget the Fox .36 Baldie of 1975( I killed that idea)
There was one Schnurel G21 .35 but only me and one or 2 others know about that thing.

Hey Marvin

Might have enough stuff here to fix up one or two of your G 21s for trade on a  Mk IV or VI(no 5?)
or good complete G.21. Have parts for bushing engine also. No new piston/sleeve but a couple of good used ones.
I have, but never used in match 3 MkIIIs, one with broken crank after about 5 runs.
Would like something that wont blow the crank when playing with it.

picture
These are all good engines and the newest I think is a PDP  on airplane. one day will look and see.
Some of these G21s have chrome sleeves and couple are still at the stock timing.
The one on left is new.
The all are as ready as they were in 1975 and are oiled and stored nicely.
I do have parts set aside to build one more all new one.

I need to cut the lugs off the engine on airplane but can't make myself do it.

David

The MkIV came out after I stopped competing. the Mk 3 also.

I have no MkIV parts!

Another member told me the thrust washer was the problem. the inner rear id radius wrong and did not match stress riser relief radius corresponding on crank thus cutting a burr(stress riser) on the crank. Well I looked close and he is correct. If you mount a prop and tighten it down the crank is damaged.
He was also correct in the fact that the washer is so hard that you cannot even grind the radius!!! H

I think I found that a .36X(old style not baldie) thrust washer works but all my cranks have had the damage done.Props have been mounted.

How Bout it Marvin?
 I discovered another G21 on a Winder hidden behind other airplanes. This one Chrome sleeve and oil grooved piston. Looks like stock timing(ie. one of Dads engines)
We can both get what we want(or think we want or need )out of this.
I sure don't have any use for this many G21s!

I would really love to check out the performance of the later Mks. Have heard the were darn good engines.
Have had an idea on a design running around my head for 30 years now but the think the G21s and MkIII don't have the umph to haul it.

Thanks for letting me rattle guys.

David

 I hope its ok to tell a probably long winded little story about the end of the Baldie and birth of the MkIII.
Hope y'all don't mind.

My parents had made friends with Duke during the 50s over some dealings with the .29Rs(Bathtub)and .29Xs
Duke hand delivered to my Mom one of the first .29Rs  for her proto to a contest somewhere.
She guarded it with her life! Twin plugged bald head and all. would not even let us change the head.
She finally turned it over to me for preserving and storing. It gets oil and put back in the box, never run.


Well that led to Duke spending most of a very enjoyable day with us at the 75 Nats.
Duke was kind of a Hero to my family. Hurt us all to hear of his passing.

Even though the Baldie was only good for 1 very impressive run as a combat engine it did make one heck of a good Slow rat engine.  with a 9X8 Rev up prop left several clicks rich it would haul. It was fun passing leaned out G21s with a rich running Fox. If it never went full lean it was good on restarts.
I think the sleeves were warping from heat.

Was standing on the side of a practice circle with Duke watching Tommy fly with one of the new bushed .36 when he asked me what I thought of the baldie. I think that his feeling were hurt. I wasn't nice.

Over the next hour or so we talked about a new engine. I wanted angled passage ways front and rear small enough to keep velocity up and opening several degrees before the main by pass.
The cheap jewelry look of the baldie didn't do it for me(saw pain in his face with that one) and that he could cast them in aluminum with a mag looking finish but that a shiny head would look good.

He kept saying he did not see how he could do the porting in the case and still have an affordable engine.
A while later he says 'I see how to do it David'  How?  David, Im not going to tell you but in a few months I will send you some engines. 6 bolt back plate was the idea.
Duke was one quite, very nice genius of a Gentle man. one of a kind.
Designed the basic layout of the MkIII in his head in the hot sun while putting up with this young smart axx kid.


Got everything that I wanted in a combat engine the year I quit flying!

He offered to replace the case of baldies we had bought and we told him no you invest that in the new engine.
Heck, the baldie was the fastest slow rat engine at the time. Think that was later cured by the bushing engine rule.

Have 3 or 4 never run Baldies in the engine dungeon ,and a pile of new ruined ones, bad choice of oil to store them in.(a rust  penetrate that turned out to be hygroscopic)

For those that do not know what the baldie is here is a pic of remaining 13700 Fox Combat Specials .

Well, back to the shop and more figuring on this stunt trimming thing. Hope I was not too boring.

David

The MK5 was the single ball+bronze shaft bearing model - had a lengthened crank and was sold in both RC and CL versions - not specifically a combat engine, though some used them in slow.

If it's got a bolt on carb adapter, that is the 'C frame' 40-45-50 series. They made a .40 Sport Pylon and an ABC .46 in that case also.

The Mk5 .36 was/is in essentially the same case as the Mk3-Mk4, with a cast in square venturi.  I don't know if it was made in the .29 size, but recently they were still selling the single ball-bearing version .40.

Thanks Greg!
That filled in some of the blanks in happening after I stopped competing in combat.

Stuck in the mid 70s
David