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Help ID this engine please


Martyn K
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Hi all
 
I bought this engine about 20 - 25 years ago for a free flight open power model. So far it has never been run.
 
( I have a feeling that the engine was really designed for a control line model)
 
I would like to resurrect it as a power plant for my Webbit mass build model but need an R/C carb and silencer. It has '21' stamped on the crankcase ( I remember it being 3.5cc in proper units) but am struggling to identify which model it is. It was definitely at the budget end so probably not an 'X' series engine..
 
 
Does anyone know what it is and possibly where I can acquire a silencer and carb for it? The exhaust mainfold bolt holes are 32.5mm apart.
 
Thanks for your help (hopefully)..
 
 
Martyn
 
 
(Not sure whether it is possible to upload images or whether that right will come after developing beyond newbie to the forum so apologies for the use of links)
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Hi Ken
 
Thanks for the reply. Yes it is definitely a SuperTigre (I hadn't realised it was one word - amazing after all this time). I would just like to use it if possible. It's beautifully finished as al ST engines are and a bit unusual in this modern world. Definitely not in the current catalogue list.
 
Martyn
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hmm, pressure feed nipple, fixed carb -G21/19? Might not be the best engine to convert to throttle as it will have advanced port timing. Just Engines would probably be able to fix you up with a carb and exhaust, but as Ken said, you might be as well off just buying a new engine. You could probably get an SC, TT or similar chinese engine for much the same cost as an exhaust and carb for this one.
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OK,
 
Thanks all.
 
I actually have an old (what else) HB21 engine of the same era. That has a R/C carb but just needs a silencer. I could probably make one or get something to fit, but from the advice above, I detect a new engine on the horizon.
 
I'll still contact Motors and Rotors though... see what thay have to say
 
Best wishes
 
Martyn
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Martyn, the "21" might not refer to the capacity. Super-Tigre engines were usually identified alpha numerically by the series then the capacity. e.g. G21/40
Also I can't remember ST making a 21 capacity engine but they did make several 23s.
If you can't get a suitable ST silencer it's easy enough to make an adapter plate to bolt to a different type silencer then the engine fixes to it.
Another point is that ST engines often used sub piston induction. Using a silencer will cut the power by a fair amount if it does. Having said that I have a very old ST G21/40 with SPI that I used to power my Magnattila before converting to electric & it was more than adequate for the job.
 
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Hi Pat
 
It was defintely either a 21 or a 19 sized engine. It was bought as a demo engine for a new free flight power class as an example of a low cost 'standard' engine, but the idea was taken any further.
 
I was told that the 21 referred to the capacity, however my source may not be reliable
 
Thanks for the advice.
 
Martyn
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Martyn.A lot of good advice above.
 
Having looked at the pictures, it would seem that the fuel nipple and needle valve are fitted into the crankcase. The venturi being a machined item probably shrunk into the same part of the crankcase casting. The venturi would have to be removed and the fuel inlet/needle valve would then be redundant and have to be sealed off.
 
It would then be necessary to drill the crankcase for a pair of bolts to retain the carb. A pinch bolt would not work because there is no split in the casting to clamp up onto.
You would then have to find a r/c carb with the right outside diameter. Which might have a quite small inlet. Quite demanding and difficult to resolve with any certainty.
 
That is unless I am not 'reading' the photo properly!
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Hi Richard
 
Good points, but apparently there is a carb and silencer available for this engine (from Motors and Rotors) which combined are a bit pricey, but cheaper than a new engine.
 
It will be interesting to see how it all goes together.
 
regarding the pressure pressure feed nipple, I actually fitted that, I am not sure I have the original screw, but I guess it will be M2 or M2.5 - easily resolved.
 
Martyn
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Martyn
 
Good motors those Super Tigres, before I went electric I had quite a few of them. I think I've still got a .29 and a .45 somewhere in the loft. I sold off the rest.
 
His son Dave is a nice chap.
 
Bert

Edited By David Ashby - RCME Administrator on 22/03/2011 16:06:43

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Posted by Bert on 22/03/2011 14:58:08:
Martyn
 
Good motors those Super Tigres, before I went electric I had quite a few of them. I think I've still got a .29 and a .45 somewhere in the loft. I sold off the rest.
 
His son Dave is a nice chap.
 
Bert
 
 
 
 
 
 
 
 
Bert, sorry but post trimmed. Please be careful what you say about people. If you're not prepared to say something to someone's face then don't say it here either - remember we're the one's who get sued, not you
 
 
 
 
 

Edited By David Ashby - RCME Administrator on 22/03/2011 16:04:36

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Posted by Mowerman on 22/03/2011 16:31:40:
Martyn
Sounds like you may have an old classic there.
May be better to hang on to it then one day a collecter may be interested.
 
I think you should use the engine Martyn. How much is an old model aeroplane engine worth anyway? £100? £200?
 
Whatever the price you'll hardly be able to retire on the procedes of the sale of your old model aircraft engines. In my experience most collectors hold on to them till they die.

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Posted by Richard Bond on 22/03/2011 14:12:47:
Martyn.A lot of good advice above.
 
Having looked at the pictures, it would seem that the fuel nipple and needle valve are fitted into the crankcase. The venturi being a machined item probably shrunk into the same part of the crankcase casting. The venturi would have to be removed and the fuel inlet/needle valve would then be redundant and have to be sealed off.
 
It would then be necessary to drill the crankcase for a pair of bolts to retain the carb. A pinch bolt would not work because there is no split in the casting to clamp up onto.
You would then have to find a r/c carb with the right outside diameter. Which might have a quite small inlet. Quite demanding and difficult to resolve with any certainty.
 
That is unless I am not 'reading' the photo properly!

I think that the venturi is grooved & retained by the NVA being in place. When a carb is fitted the NVA is replaced by a stud with an arc machined out of it & is threaded at one end. When the carb & stud are in place it a nut on the threaded end pulls the arc to clamp the carb. That's how the carb is held in my G21/40.

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Posts coming in fast.. thanks
 
I haven't stripped the engine so I am not sure how the venturi is held but the description sounds reasonable. I'll find out in due course
 
Regarding collecting. Unless someone wants to make me an offer (quickly) - and it covers a new comparable replacement than I probably wont be interested. (or a good swap)
 
It is a rather nice engine though. ST used to make their crankcases using sand castings - gives a beautiful look and feel to it.I have a feeling that it will soon get soil ingrained though.
 
Martyn
 
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