General Aeromodelling Discussion

Tug, That is a fine looking model and should have an interesting future with the Merco 61 fitted.! Keep the information coming. In the 60s that was the engine to have for stunt flying. About 3 years ago, I was given an open cardboard box, by a friend of a friend, that contained several very dirty engines,that had belonged to his late father-in -law, a keen stunt flyer. One of these was a Merco 61 and like yours was totally gummed up. It cleaned up quite well, but I only removed the head and the backplate. It had a lot of carbon on the top of the piston, so had been well used,but still had super compression and had clearly been looked after. On test, my notes show it was running at just over 12000 RPM with an 11 x 6" Master prop. Also in the box were 7 Cox.049, all different, plus another glow engine of about 8cc that I have been unable to identify. General opinion is that it was a hand made prototype.

Tug, The unidentified engine is in my photos, in the Chennery Vee Twin album ,3rd row down.. Just in case you can recognise it.

Keith.

Hah! Tell me about it Bob but I'm definitely slowing down now, age really is beginning to tell

Keith - that's more or less how I acquired this one but stripping it down completely proved to be rather beneficial !!.....

Looking at your unidentified engine I would say that that is almost certainly a home build. The prop driver is a give away I feel.

What are you up to at the mo?

Tug

PS anyone else had any of this aeromodelling deviation - Hmmm. Thinks! does that make me a deviant

Tug, I agree about the odd prop driver. I does not relate to the rest of the engine ,which has been made by someone witth similar milling skills to yourself. Recently I have been re-testing some of my engines on a new rig that measures static thrust. Also sorting bits out to make another of Chris Bolls designs. This time an 8cc glow.

Keith

Keith

Whoever made the engine didn't go the whole hog, they bought a Perry carb, or robbed it from another engine they had, very strong engine around the front end.

Emgee

That's another area that points to a home build Emgee - the way the carb is attached to the engine.

Have you run it Keith ? It looks like the fins and liner are possibly integral. Another Merco 60 I have is similar. Haven't run it but would think that heat build up could be an issue compared to the liner and ali fins version ??

Has Chris Boll published that design as not familiar with it?

Tug

Edited By Ramon Wilson on 13/08/2021 09:32:21

Emgee, Tug, I wondered about the Perry carb at the time. In fact ,it was the first time I hade seen one. To mount it with its side screw fixing,a very neat,shaped flanged stub tube with two mounting screws to hold it all down on the front bearing housing is fitted. The front bearing is another type of Ali bushed in the housing. I have a suspicion that a ball bearing is fitted to the crankshaft, but I have not removed the front to see. The fins are integral with the steel cylinder. The plain piston has a deflector on the top, with matching space in the head. I have run it two or three times,with 5% fuel, getting 11600RPM. For some unknown reason ,I have not noted the prop size, probably a 10 x8". I did not notice any overheating problems..

Chis Boll did publish in ME in 2016,I believe as a .49cu/in Glow. He says ME made a mess of it ! I got hard copies of the drawings direct from Chris.

Keith

11600 RPM is pretty good on a bench run with an 8" pitch prop Keith (if it was 8" - is it a plain or ringed piston? Sounds a powerful beast.

I think somewhere I have a Perry carb - you are welcome to it if you would like it - and I can find it of course

I've heard several bad tales of magazines, not just ME though, getting things wrong, even changing the contributers ideas but have to say as far as the articles they have done for me I thought they did fine job. I was certainly pleased with the results for sure.

I'll keep you posted on the airframes - just been glass clothing the nose of the larger one, just a single layer of .6oz and applied with a two pack floor finish similar to the old 'Tufcote'

Tug

Morning guys,

I finally finished one of those airframes - thought you might like to see it.

It's covered in jap tissue and clear doped with a tint of red in the dope. The fuse is painted with aerosol - 'CanBrush' a very hard wearing and easy to spay paint. The colour looks white in the image but is actually a nice cream.

Weight (always important) is slightly heavier than I would like but is 44.3 ozs all up. Power is a Stalker 40 glow motor and if the weather's is okay first flights will be on Sunday.

Tug

PS There's a couple more pics in my albums if you are interested

That looks absolutely superb Tug. It seems a shame to make it dirty. Good luck for Sunday.

Keith

I agree, that really does look very nice indeed. I have always thought when building up wings/frames etc it seems a pity to the skin the structure in balsa/solar film etc hiding all the detail. Much nicer to see the build as you have with the see through tissue.

At 44 ozs I would think it should fly well with a 40 size engine.

Good luck with it.

Ron

Thanks Keith and Ron,

Yep it's never the same once that first coat of castor goes on Keith . I do have a good cleaning regime though that should keep it looking fair for a while.

The covering Ron, is traditional heavyweight Jap tissue sadly no longer available. As you say though once it goes on all that intense work of previous weeks is quickly hidden. I would prefer to paint all over but that does bring the weight up considerably - keeping it clear doped helps with that as well as having a nice 'traditional' effect.

Although I don't compete any more this model design is from what is termed the 'Classic' period - models that were designed/published between Dec '58 (I think) and Dec 69. Well it was in my time but has been extended to Dec 1979 to encourage more input. Some of the models designed between 69 and 79 are certainly classics in their own right if not quite in keeping with the original period to my mind.

Any one else build and fly control line on here? Be good to hear from you if so

Regards - Tug

Gentlemen, I have two Murco 61's if anyone is interested. There is one carb but not serviceable and one non standard exhaust. PM if you wish.

Robert Butler

Hi Guys - The Coy Lady flew very well indeed so I was well pleased with the outcome. Having become a fair weather flyer in my old age it will be next year before it gets another outing though

I've been building another 'classic' period model, another favourite. It's an American design from 1959 called the Tucker Special. I've enlarged it slightly from the original 50" wingspan to 56" and power will be a Super Tigre G21/46.

Again, due to weather conditions it will be on hold until next spring before I can cover and paint it.

Also been doing some engine repair work and dieselising an OS Max FP20 glow motor - very successful.

Hope to be back on the marine engine before long though - anyone else balsa bashing?

Regards - Tug