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Sunday, August 25, 2013

The Rare Vintage Russian MK12 S Competition Engine Story


MK-12 S
ManufacturerUSSR (CCCP)
DistributedUSSR (CCCP)
Series / Serial No.s / n
Year of manufacture1956
Displacement2.47 cc (0.151 cu. In.)
Bore15 mm. (0.591 in.)
Stroke14 mm. (0.551 in.)
Power classDiesel
Type of carburetorFixed (no speed control)
AdmissionRear rotary valve

Crankshaft on bronzeNo
FuelEther / Petroleum / Oil
CommentsRussian Motor manufactured in small series, earlier model MK-12 B and V were found to be copies of Webra Mach I of the same displacement. Rear rotary valve, bearings and steel jacket with radial transfer. The piston is meehanite.

This engine was designed by the famous Russian modeller O.K. Gajewsji and was released to the public circa 1956.

The engine was used for competition freeflight and control line team racing. The following picture shows the individual parts.

The Russians called this engine the Motop MK12 c (cyrillic, 'c' is 's' in English).

The engine was received complete with a first place competition medal, a wooden propeller and a length of fuel tubing

Engine Box

Items found in the box.
The swallow logo is also stamped on one of the mounting lugs

There are two versions of the competition engine: the MK12S featured here and the more powerful MK12K shown below. 
The main differences are: a thicker prop-driver; a different spray-bar assembly, and a red ring around the cooling jacket inscribed with the name MK12-K

Specification sheet from a book on Russian engines written entirely in Russian
This same publication claims a maximum power output of 0.357 horsepower for the MK-K engine  

OK! Enough of this technical discussion; its time for a test run to see how she will perform.

Cold start with a 40/30/30 fuel mixture of kerosene, ether, and castor oil respectively. The propeller is a 8X6 Master AirScrew.

Monday, August 5, 2013

British AMCO 3.5 cc PB Rebuild Story

 Allbon Spitfire and Amco 3.5 cc PB Rebuild Stories

AMCO 3.5 cc PB
ManufacturerAnchor Motors Co., Newgate, Chester, UK
DistributedAnchor Motors Co., Newgate, Chester, UK
Series / Serial No.s / n
Year of manufacture1948
Displacement0,2.14  cu. in. (3.5 cc)

Power classDiesel
Type of carburetorFixed without speed control
AdmissionFront rotary valve (crankshaft)
Inner bearingNot
Outdoor BearingNot
Crankshaft to crankcaseIf
Crankshaft on bronzeNot
FuelEther / Petroleum / Oil
Comments This is a classic diesel steel jacketed radial transfer four channels, casting piston and crankshaft mounted directly on the cast aluminum crankcase. 

Rebuild Story:
These engines were made in Chester England until April 1952 when the company was sold to an aeronautical electronic engineering company

Reproductions from CS in China, Arne Hende have been available in the past
This is typical of the damage that occurred on those early Amco engines when the crankshaft failed.

Two new extra light piston with a drilled out wrist-pin made from chrome vanadium steel were the first items I made for this project

To improve gas flow I smoothed out the lead in to the transfer flutes at the bottom of the cylinder and removed the sharp corners inside the crankcase.

I purchased a vintage Ambird Sportsman C/L plane and this Amco is one of the engines considered to power it. The Amco has an exhaust stack option.....so I decided to take that idea one step further......   

This is an over square design where the bore is lager than the stroke (17.46 to 14.29 mm respectively). The power output is just under 0.3 horsepower with a constant torque from 9,000 to 13,000 R.P.M.
The older used engines have heads burned brown by the heat, where as the new engines were made with black anodised heads.

The AMCO PB was a sensation when released because of its light weight and high power giving it an unbeatable power to weight ratio. In the beginning there were problems: the crankshafts were too thin and had a bad habit of failing without warning. Engines after serial number 5000 were much better with redesigned thicker wall cranks.

I have one complete engine and one that is missing the piston and connecting rod and I intend to make these missing parts.The original engine had an extremely heavy piston and an unbalanced crankshaft; I will correct these problems in my engine by machining out the useless internal material from the piston and hope the resulting power output will be in excess of 0.35 horsepower.  

Original parts shown on left and my improved designed parts with the counterbalance crank; drilled out wrist-pin made of chrome vanadium steel and slotted connecting rod big end on the right. 
One of my new light weight pistons and connecting rods with its slotted big end, for improved lubricating of the crank pin.
These are the engines I was considering powering the antique plane with.

The optional Amco exhaust collector stack makes a handy mount for the custom twin mufflers.

The stock engine on the right and the modified engine fitted with its twin mufflers on the left.
OK! Let's take it outside for a test run, but I must not forget my chicken stick; I need all my fingers for these rebuild projects.

The engine will still need a lot more runs with increased oil content in the fuel to properly be run-in, then the power will increase noticeably. Propeller size for these first runs is a 9X4.  

Published on 21 Jul 2013 After a quite period on my channel a new episode of another British well known diesel. The notorious 3,5 AMCO "finger-biter". The Amco company made only 4 engines.The 0,87 diesel in 2 versions,and the 3,5 in plain and ball bearing.The Amco had a good reputation established by their first 0.87 diesel engines.Thats why it survived after the early 3,5 failures. The crankshafts were too thin,and combined with a soft alloy conrod; most  never survived long enough to get old. The mistakes were corrected by AMCO, and the engine was very popular in control line flying and as a free-flight engine; mostly in the UK. My two engines are ser. numbers 8450 and 8483!! So they were produced at approximately the same time. Engines from numbers 5000 and up are known as the better ones. The intake passage in the shaft is smaller and that gives a thicker diameter to the rod, which is also made from better materiel. It has a lower rpm output, but it will hold together ...and run for many hours. I have 2 examples, one is a poor runner, since the wrist-pin and rod are worn out. The other is almost new, but is missing the piston, rod and wrist-pin. I made those parts new, but made the wrist-pin a little bit thicker.(3,6 mm to 4,0mm). The heavy piston is reduced in weight together with a drilled out pin. Further I added the crank-web counterweights, which makes the engine run very smoothly now. A radical short stroke engine with a heavy piston is not a good idea. Amco should make at least some efforts, to change this condition in their design. But I guess money is like always the reason behind this shortcoming. I would like to use the Ambird sportsman C/L plane. The excellent power to weight ratio and long shaft make it an ideal powerplant for that project. I changed the wing design (thicker airfoil and build up wing instead the 2 piece prefabricated wing); added flaps and build the bird far lighter than it was intended by the kit designer. The nice exhaust will make it for sure a nice vintage racer. After maiden flight is done, there will be a clip of this nice and rare racer! Thanks for drop in and more diesels and rebuilds on my channel;. And many more engines still to come. Keep your fingers out of danger and happy flying!
YouTube Channel Valic000


Saturday, August 3, 2013

Running the Polish Jaskokla 2.5 cc

History and Background:
Year of manufacture 1954
Built as a front through the crank induction and a rear reed valve


Jaskokla 2.5 cc
ManufacturerJaskolka. Poland
DistributedJaskolka, Poland
Series / Serial No.s / n
Year of manufacture1955
Displacement2,5 cc (0.15 cu. In.)

Power classDiesel
Type of carburetorFixed without speed control
AdmissionResonant rear Valve (vibrating membrane)

Crankshaft on bronzeYes
FuelEther / Petroleum / Oil
CommentsOne of the firms that have produced different models and engines in Poland is Jaskolka of  various displacements. This model is equipped with  radial transfer in the cylinder, piston and valve meanita rear resonant admission.


Published on 29 Jul 2013 Again a warm welcome for lovers of old model engines.We look today at a model diesel engine made in Poland around the years 1954/55. Its very hard to find accurate information about the Polish vintage model engines for those living outside Poland. Thanks to a subscriber I found out that the output if the engine is 0,22 hp@13000 rpm The Jaskolka has a good internal finish,but the outside reminds me of the MK 12 b from Russia..Not the nicest castings, but its what's inside,what matters.....right? I was very lucky to find a boxed engine in decent condition..The compression is not the best and the clack valve was stuck from old castor oil which prevented any fresh air from entering the crankcase. After opening up the valve i found it was not sealing 100%. Fixing this took me hours of work to make it work at least somewhat better. The membranes are extremely sensitive for distortion and sealing. I get it working with a lot patience. Also a new piston will soon be made..Maybe I will be lucky one day to find a FRV Jaskolka on E-bay..When I purchased this one on Ebay, there were 4 other engines from the same seller on auction. I missed the FRV version,........BUT!! I got a brand new SUPER SOKOL 5 cc diesel,what is a very interesting engine,because its very nice made,and has a deflector on the piston and a contra piston of course.How they made it?... I let you know...soon! :-) But I am more than happy with this hard too find vintage engine and especially the lovely box! The big brother of the Jaskolka, the Super Sokol will be run soon: here on my channel,with much more rare old model diesels...so stay tuned! I have not always a lot time to make those vids,but I do my best,and I hope you guys like them. Feel free to suscribe if you like old model diesel engines. I hope you like the short clip! See you soon..

YouTube Channel Valic000

Running the Engine: