What info can you share about these engines. I'll post pictures when I figure out how. I can email pictures to those interested.

OS MAX. 20, older, looks like muffler, if one, attached with single bolt centered in exhaust.

OS MAX-H 29R-integral spinner

McCoy 19 rear intake-head and front of case is red, the venturi is part of the rear case

Tipan (sp) 2.5cc rear exhaust r/c carb.

Thanks,
David

I've not had experience with these BUT they are all very old engines- 1950s-60s.   The Max 20 might be useful on a small airplane like a Ringmaster or smaller.  The Max 29 was built for speed,  or maybe 'B' team race.   The McCoy is early in the glow era-maybe 1950-54.   I won't produce a ton of power but might run well.   The Taipan I know nothing about at all.  I'm sure this didn't help much...

Dave

If theyre not clapped out , theyre usefull .

Usually youd strip & check the wrist pins free & polish the gunge off of it . etc etc and so on .

the 20 is usefully LIGHT , and good instead of a .15 for combat , peacemaker , flite strea etc . theres the old jetstream & newer 702 ? strap on muffler . 8 x 6 or 9 x 4 prop . o.k. on NO Nitro .

PULL THE HEAD & BACKPLATE , if its squeaky clean should be good , if its effluential clean & polish the bits wots supposed to be shiny .



The H 29 R , is a T B R big shaft OS 30 S . AS IN the rod , wrist pin , liner & piston are THE SAME . ( and findable new )
was a SPEED engine , but used for team race . ( was a rare H 29 TR too ) bout the same as a Enya TBR or S Tigre 21/29 FI almost .

Probly run good on a 9 x 6 or 10 x 6 for stunt ! 

the 60s OS max H 40 with RC stamped on a round bit , and a .35 C are simlar but single ball race ( some parts interchange )
The RR & SP ? were TBR .

The weird narrow rear bearing is still available as a special , from NTN .

The 35 s P/L & Head would .35 erise it . a Gardner ABC H 35 S ! 

These old dogs often have gummed wrist pins , which wont help anything . If its Not stored Oiled . So CHECK its clean inside .

the OS 40 stunt etc intakes ( & FSR ) fit . came out around 1965 with the .35 C . theres wedge & hemi heads .

In short , all the ones pre the h 40 with JUST . 40 cast on the side , are related . the 20 & .25 are very similar .

TBR & SBR prop drive are tell tale . for that .

Thanks for the information gentlemen, especially the articles on the Taipan 2.5cc and the McCoy 19. My Dad had these two as long as I can remember, at least 40 years. I don't remember him putting wither on an airplane.


David

If'n ya lookat the Injun Tests , theyre running - LA 15 Vs max 20 - about the same rpm on 8x5 & 8x6 props , or the 20's better . LA has a few more revs on a smaller prop , tho theres NO output graphs for the LA ,
one would presume its got higher rpm peak . LA is a ounce or two lighter . A intresting fing , is a old max .15 will swing a 9 x 4 just about as hard as the .20 , for 2/3rd the weight .

A OS max .20 will fly the aeromudler ' Peacemaker ' ( 36 span profile flight streak ) on 60 foot of .012 through the schedule , at around 15 ounce all up , on a balmy summer evening , on STRAIGHT FUEL . No Nitro .
bit tighter on 52 foot . 55 probly the best choice . A GOOD one is a GOOD ENGINE .


ACTUALLY ONE ( the outer ) would do repeat consecutive wing overs , muffled , straight fuel , on a 38 ounce twin 50 inch span , profile twin .
IF you KEEP IT SMOOTH , And the Rounds below 45 hight . The 4th consecutive you start to pull out upright , out of it , and then slam on DOWN .
The whole row of onlookers eyes were - left - right - left , right , etc . the Whole Row looked left and Ducked & Covered as a man , as it went opposite .    .

Was actual 41 Oz. wiff mufflas .

Eye detalkil , almost . butof better wood . Both for full schedule , 60 x .015 or 70 x . 012 IN THE CALM . 1974 / 75 TORBAY . crucified unsecured by a moron s top box on the motorway . GROWN UPS ! .

Vintage Os max 20

on u tube . theyed fly a light 40 inch R C thing . the .25 will pull a B team racer at 90 for 5.000.000 laps . Twice a race .29 , anyway . Same Injun , but 25 % bore & stroke job .
Theyll blow off a dungey Oliver 85 mph combat wing , with a drop of nitro . Bout thesame with none . around ' the tow ' of a .19DS paw , in fact .20 5 nitro'd have a clean goodyear past the ton , on say a 7 x 8 prop .

Was ,likely my first ' new ' engine too . If we dont c*unt the katipo ( or the other way round )
 which after the entire district gave up trying to start after six months , was likely sufficently loose for ME to start , to their dismay .

We used Castor from the chemists and bulk shell methanol . And religiously followed the instructions . Tell a lie , think the DS PAW was before it . But No Nitrate and it was a finger butcherer .
Took Off once with the Flingle Bunt - first loop I think . Such Power ! sufficent to wreck it on the next flight anyway , having to adjust the settings for each ' start ' .

Previous it was a sucession of used diesels 7 glows . U.S. ones with NO NITRO . dismal , green head torps & the like . that had previously suffered . All bar the Mills cause shock & trauma on recall
of their usefullness . ZILCH .

the OS 20 were $ 30 N.Z. from Radar Co. in Kowloon , Hong kong . Was lectured by a turkey in the nzmaa that we were disloyal to the country and should buy them of the mangey pom for $ 130 .
" But theyre all R.C. , we want control line " . -. ' oh no , thats extra , you have to buy the r.c. ' Arsey Indeed . You can figure . I figure youd get rid of most of the crooks if you deported 80 % of them .

FROM RADAR they came with THREE ventuies , stunt , std , and Combat , with the pressure nipple . I think thet was what went in the 30 , the biggest . 20 one , was smaller than std . .30 .

SO , just running em for a few hours ( always in fact ) without NITRO , I think the ' run in ' has as much to do with it as a carefully assembled pommy motorcycle .2000 miles to free off , then still getting faster at 5000

The g 15 had a year or more on no nitro , later with 10 5 it'd top out at 24.000 in the air on a taipan 7x6 . 120 odd . tho earlier It'd broken the sound barrier flying it in a hurricane . 

So , for me , anyway , the ' bedding in ' proceedure on this ancient junk makes it or breaks it . swy a 650 would run a 900 kaw & a 750 Norton a xs11 , aceleratively , or betterem .
MISSUSE of the next owner the clapped out t120 with one intact ring , rooted clutch & no go or bite stuill ran 14.5 @ 90 . same as the RingDing 350 there , at the ' Sprint meet ' my then A10 ran 16.9 @ 81
as they did new , but Id thought i couldve gone faster afoot , than with that . NZ also is a cooler place without the searing summer temperatures of the big continants .So less duress when under duress !