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Old Jun 15, 2014, 07:10 PM
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Question
Worth cleaning up these diesel engines?

Hi all, I have inherited a couple of fairly old diesel engines and interested in getting at least one back in the air.

I have zero experience with diesel engines as I fly primarily large petrol models and gliders but love a good build and these little engines have piqued my interest.

I gather the larger engine is a Mill's 1.3? (which I am mostly interested in) but not sure what the smaller one is, it looks more modern than the other.
Clearly both engines are in serious need of a clean up but turn freely and seem largely intact.

What I would love to know:

Is it worth cleaning up either of these?
Could someone help me confirm the ID of these engines?
If I got one or both running what sort of vintage airframe would suit? I imagine these were originally used in free flight models (1950's?)
What sort/brand of fuel is suitable for these engines? The documents refer to Diesel 2 Modelair fuel which of course is no longer available

Any assistance much appreciated.
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Old Jun 15, 2014, 09:40 PM
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Gold Coast Australia.
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The big one is indeed an original Mills 1.3cc from the late '40s or '50s.......If you put the numbers here that are on the lugs we can tell you the year more that likely.
The missing fuel bowl should be not hard to get, and the screw on the front of the crankshaft is a BA size.

The small one is a DC Merlin, .75cc that first came out in 1954. Both engines made in England.

Soak them in acetone for a start, and scrub them with a tooth brush.

Good fuel for them is equal parts of ether, Kerosene and castor oil.

There are heaps of models from the '40s/'50s that will suit either engine. Just check the plans section on this site.
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Old Jun 15, 2014, 10:25 PM
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Many thanks Gossie for the great information. The 1.3 engine has the numbers 38 and 497 stamped on the mounting lugs.

Looking for an old toothbrush right now to start the cleanup..
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Old Jun 15, 2014, 10:48 PM
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Blenheim, NZ
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The Mills is special and worth a bit if it is any good I suspect. The DC Merlin not so much. There were many of them about and not all ran so well. I still have a good one that starts imediately and is great for scambles (Aggy in NZ) but I do have the quick start spring fitted.
Don't attack them with a wire brush will you. Just take a soft approach. I find soaking in meths frees mine up too. It is just a case of desolving the Caster residue usually.
Ah... the memories.

Allan
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Old Jun 15, 2014, 11:37 PM
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Hi Allan

I will be gentle and concentrate on the Mills I think. I'm currently looking through free flight plans from late 1940's to early 1950's and figuring options to put it in.
I know my father (to whom the original motors belonged) had several original plans which have now sadly disappeared, the only one I remember is the "Frankenstein" from 1949 which he never got around to building.
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Old Jun 16, 2014, 12:47 AM
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"Frankenstein" would be perfect for the Mills 1.3. Other good options would be the Keil Kraft Bandit and Outlaw (the original Bill Dean Outlaw, not the later radio design). Veron Cardinal, Smeed Tomboy, DC Ballerina, KK Bantam or any one of a dozen Smeed models would suit the Merlin.
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Old Jun 16, 2014, 04:36 AM
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I can recommend Paul Plecan's Hepcat for the Mills 1.3. One of the prettiest models there is (in my opinion of course). Some links attached:

http://www.outerzone.co.uk/plan_details.asp?ID=2188
http://www.youtube.com/watch?feature...&v=XuGpBz2Hdew
http://www.benbucklevintage.com/inde...products_id=77

...and some Mills history...

http://modelenginenews.org/cardfile/hardinge.html

As long as nothing is cracked or damaged, you should have no trouble getting the Mills to run once you have removed the old fuel residue.
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Old Jun 16, 2014, 05:22 AM
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Thanks Deebee1, the Hepcat is indeed a beauty! The history link also much appreciated, I'm going to have a good read through very shortly.

I've decided to concentrate on the 1.3 first and tonight it cleaned up pretty much like new with a little meths and a toothbrush. Still a bit of residue lurking in the brass fuel tube and needle seat so giving those bits more of a soak.
So far nothing looks damaged or worn so high hopes it will be a runner. Just need to source a replacement spinner/screw and replacement fuel bowl for some bench runs.

I have the Mills prop chart but keen for feedback if there is anything I should avoid?
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Old Jun 16, 2014, 05:05 PM
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Did someone say FRANKENSTEIN?

I built this one in 1981 for an ED 2cc Competition Special, and it's a great Free Flight flier, and absolutely ideal for your Mills 1.3.
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Old Jun 16, 2014, 06:30 PM
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This really has the brain working overtime.
I like the idea of building a Frankenstein. Mainly because it is a model Dad's 1.3 was originally intended for way back in the day. On the other hand, I very much like the look/design of the Hepcat!

I guess first step is to ensure the engine is in good working order. After it came up so well following a clean I'm a little paranoid I might miss something I should check for before starting and then damage it. No electric starter will be going near it so hopefully I can't go to far wrong?
Its the first diesel I've had anything to do with and I suspect this engine has not been run for more than 50 years!
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Old Jun 16, 2014, 07:46 PM
Isaiah 40:31
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Subbed. Looking foward to see what comes of this.
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Old Jun 16, 2014, 08:39 PM
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Quote:
Originally Posted by MaXziim View Post
This really has the brain working overtime.
I like the idea of building a Frankenstein. Mainly because it is a model Dad's 1.3 was originally intended for way back in the day. On the other hand, I very much like the look/design of the Hepcat!

I guess first step is to ensure the engine is in good working order. After it came up so well following a clean I'm a little paranoid I might miss something I should check for before starting and then damage it. No electric starter will be going near it so hopefully I can't go to far wrong?
Its the first diesel I've had anything to do with and I suspect this engine has not been run for more than 50 years!
It's a 2 stroke, so with compression and good fuel as I suggested and a 9 X 4 prop. it MUST run.

Why not build BOTH models that you like?
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Old Jun 17, 2014, 01:19 AM
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Originally Posted by gossie View Post
It's a 2 stroke, so with compression and good fuel as I suggested and a 9 X 4 prop. it MUST run.

Why not build BOTH models that you like?
Two airframes would be very ambitious as I'm not a particularly fast builder! I will carefully select one to concentrate on in the first instance
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Old Jun 17, 2014, 09:52 PM
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MaX, I thought by now someone would have come in re. the numbers on your 1.3.

I'm not sure, but think the 497 may mean it was built in July of 1949.
I stand corrected if this wrong. Perhaps someone knows the meaning of the numbers for sure?
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Old Jun 18, 2014, 12:10 AM
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I don't think this is as early as 1949.
The early 1.3's Series 1 have the inlet higher on the rear face (see the nut is almost against the cylinder flange).
The later Series 2 had revised inlet timing (for more power) resulting in the inlet mounting lower (see there is now a space above the nut).

MaX - just noticed that your 1.3 actually has a 0.75 inlet fitted. I don't think this will have much effect at low revs with a sensible prop (9x4 or 5), but it might knock the edge off high rev performance.
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