V 12 engine's

[leerkracht]

Hello

some of my creations




gr

 

[jcreasey]

Wow, beautiful work! How long did it take to build?

 

[leerkracht]

V 12 60°
crankshaft 4140 nitrided (42CrMo4)
cilinder-liners + piston rings GGG40 (nodulair cast iron)
all the aluminium 7075 T6
OHC shaft "Star as ' Hardened Stubssteel lobes )
oil pump like the real engines

 

[sition]

good job

 

[petertha]

Very, Very nice! Tell us more about it.
- your own design?
- looks like glow plugs, how are you driving them electrically?
- is the crankshaft one solid piece or has been segmented?
- what about the carburetor's, looks like 12 individual venturi trumpets. Are they actually separate per cylinder, or...?

Would love to see some build pictures if you took any.

 

[leerkracht]

V12 180°

my own design
glow plug > temporary 2x 2v lead cell (ignition module must be completed )
crankshaft one piece propshaft apart
carburetor one with blower 2.5 crankshaft speed ( internel gear )

gr

 

[Peter Twissell]

Nice work.
Where did the blower design come from?
With no space around the vanes, it will not be effective. It needs the space so that each vane can accelerate the gas as it passed through. With no space, gas can only accelerate at the one vane which is passing the exit.

 

[petertha]

leerkracht, I'm curious about your plugs & what looks like distributor. Maybe I'm getting mixed up between engines, but on the V12 flat blue
- are they glow plugs with modified (white) stems to mimic plugs or help with connecting the wire harness?
- so then is the distributor actually connecting (timed) voltage to each plug, or this serves some other purpose?

Really nice work, including the radial! I think you should do a build thread on each. Even if its its 99% pictures and a few words

 

[awake]

Incredible work! And what a lovely, throaty sound!

 

[bluejets]

leerkracht, I'm curious about your plugs & what looks like distributor. Maybe I'm getting mixed up between engines, but on the V12 flat blue
- are they glow plugs with modified (white) stems to mimic plugs or help with connecting the wire harness?
- so then is the distributor actually connecting (timed) voltage to each plug, or this serves some other purpose?

Really nice work, including the radial! I think you should do a build thread on each. Even if its its 99% pictures and a few words

Photo 3 appears to be the glow plug engine.
Other with spark plugs and 2 distributors is a vee ( different) engine

 

[leerkracht]

Hello
the blower and the rest of the whole engine design is according to my own insight/ Perhaps it is better to provide a space around the rotor so that the mixture can accelerate and achieve a better yield.

the glow plugs are only temporary to make the engine work anyway, in the meantime this engine runs much better than you can see on the video. This was one of the first times the engine was running, now it is better tuned with a good result, and a very regular running.

the ignition on the blue 12-cylinder engine still needs to be made,

the picture with the ignition plugs (Rimfire ) shows how the connection will be look, the white distributors are mounted on the v12 of 60°, one for each row of cylinders, they work with a Hall censor and 6 magnets ( and 2 electronic module's of Roy Scholl ) to supply the whole with the necessary voltage.

the 9 cilinder radial engine was my first project 30 years ago
the design came from a technical school in germany, to this design the necessary adjustments have been made, some of you will recognize the cylinder heads to a design of Forest Edwarts,(from the radial 5) also this engine runs vibration free.

both 12 cilinder engine's are my own design

gr

 

[leerkracht]

Hello
Another radial engine
this was a school project with my students from the 7th specialization year cnc a few years ago, we left based on a actual plan ,this design has been completely changed by me, both internally and externally,by example screwed cylinder heads (so students can learn how to mill cnc threads) like by Pratt & Whitney , large inlet valve and smaller exhaust valve, changed timing / blower for a good distribution of the fuel mixture and so on, this engine is fully cnc made on a CTX 210 lathe with Shop Turn control and a DMC 635 Mill with Shop Mill control, my profession is teacher in a technical school where I teach cnc, design and some other subjects.

this motor runs on methanol with glow ignition with support of a Star Glow 7 module.

bore 26 mm stroke 26mm

then you can still see the mold for making sparkplug connections (RTV high temperature silicon rubber)

gr

 

[WOB]

The flat 12 intake manifold does not work correctly. When the front cylinders are receiving the correct mixture, the rear cylinders will be too rich. This is shown in the video by the excess exhaust vapor coming from the rear cylinders and nothing visible from the front cylinders. The volume of the manifold plenum and its diameter is much too small and it runs cold. The result is a huge variation in mixture composition due to the long distance and small diameter of the passages to the front cylinders versus the rear cylinders. There is plenty of time for the mixture vapor to condense and drop out on the cold walls of the manifold and runners. Also, the little supercharger does nothing but stir the mixture a little but is too small and runs too slow to provide any manifold pressure. For the engine to develop full power in all cylinders the manifold needs a larger volume with the shortest possible runners to each cylinder and a centrally mounted carburetor. Actually, it probably needs 2 or 3 carburetors for best running because of the length of the engine block. I know this is contrary to the original design concept of a supercharged aircraft engine from the 1940's era, but full size engines don't always scale properly.

On the other hand, the machine work and overall appearance is superb.

WOB

 

[leerkracht]

hello
As an example a picture of the Lycoming 0-1230 flat 12 aero engine served as an example, as mentioned the video is one of the first runs of this engine and after some adjustments it runs very well now ; the function of the blower was only to get the combustion mixture to the top without too much difference for the individual cylinders, by the way a model carburetor does not provide a combustible gas but rather a mixture of air with droplets of fuel in it. but it works

When this engine was ready it ran within 5 minutes and this with a hand start, then you can still say that everything is ok . Don't forget that here i started with a white blank paper and designed everything ourselves

I can place 3 or more carburetors but then the view changes too much and it's not flat anymore.
the Lycoming 0-1230 was flat because it had to fit in the wing of an aircraft

The rpm of both 12 cil engines is 3500 idling 700 rpm just like the real Merlin by example


the speed under load of the 9 cylinder radial engine is 6000 rpm even with these thin and long suction tubes
even with the real one engines of the 1940's not all cylinders have the same mixture but they did what they had to do

the OS 7 cylinder FR 420 also has a radial blower that runs at the same speed as the crankshaft if it really didn't work then OS would have left it out.

For me, the hobby is to design and manufacture a engine : that is beautiful to look at on the outside, and inside of a quality that everything can function properly without hurting any parts, if after completing everything works then I can be satisfied, but this said you can always give constructive criticism.

both 12 cylinder engines and the 9 radial are fullymade with conventional machines (Emco Maximat 11 and Emco FB 2 + the Quorn tool and cutter grinder) except for the master cam for grinding the cams, also the blower rad and the cam covers.(cnc) al the other parts are time consuming hand make's

gr

 

[petertha]

Very nice work & informative text leerkracht, thanks for sharing.

On your (methanol glow plug) radial(s), I would like to hear how you did the lubrication, particularly the nose case section with cams & gears. I'm building an Ohrndorf 5-cyl. My post is here if you would like to comment or contribute.
https://www.homemodelenginemachinist.com/threads/radial-lubrication.31739/

 

[Peter Twissell]

When designing my 7 cylinder radial, I incorporated a blower with a 2 speed drive.
Most of the time, it runs at crank speed and serves as a mixer, keeping the fuel/air moving and reducing fuel condensation.
Engaging the high gear round the blower at 4 X crank speed, with the expectation of some degree of boost.

 

[SPOTTER]

Non ho parole, semplicemente fantastico, sei un genio

 

[Foketry]

Great and beautiful works,
I would like to ask you some technical information because I would also like build an overhead camshaft engine
In the photo of post N. #5 under the camshaft there are small cups that press the valve .
These cups work directly guided in the aluminum hole or you put bronze bushes ?
Are lubricated by oil these cups ?
Thank you for your answer

 

[leerkracht]

hello
The cam followers ( cups) are made of Stubssteel and hardened , at the v12 of 60° they move directly in the aluminum cylinderhead , at the v12 of 180° there are bronze bushings provided made from RG7 , the lubrication in both engines is supplied by the brass tube which is visible on the picture.(post 5)

cam follower before grinding /and polishing 2 hole's for venting

Bronze ( RG 7) bearing (two piece) for crankshaft presurised lubrication

cam lobe's 300°

connecting rod direct rotating on nitrided crankshaft ( pressure oiling )

 

[Foketry]

thanks for your kind and professional answers
I will use the same system for the straight 8 cylinder engine that I am designing now