A Real Dake

My dad scratch-built a Dake many years ago, and it took me a long time to figure out how it worked.

It is a twin-piston engine, with flat pistons like slices of toast, with one piece of toast riding inside the other hollowed-out piece of toast.

Originally designed by Roots, and then 20 years later modified a bit by Dake and re-patented. Dake actually put the engine into production, and quite a few were manufactured.

It was a very advanced engine for its time, and reverses almost instantly.

Starts in any position.

Used for hoists, steering engines, and other applications that can make good use of quick reversing and no dead centers.

So the other day I was surfing ebay, which I generally do every few months, and low and behold I ran across the only Dake I have ever seen for sale.

Of course I had to grab it.

Lets hope it survives shipping.

This is one of the fluted crankcase styles, which seem to be rather rare.

This one is set up for a remote reversing valve.

Normally the reversing valve sits on top of the crankcase.

Edited By PatJ on 28/12/2022 09:49:44

This is the Dake 3D model I created a few years ago.

Edited By PatJ on 28/12/2022 09:56:10

Pat,

That looks neat. I know nothing about this design but am now trying to digest a website that lists those kind of  designs eg 1856 Roots Patent ... http://www.douglas-self.com/MUSEUM/POWER/squarepiston/square.htm

Quite fascinating.

Thanks.

Ches

Edited By Ches Green UK on 28/12/2022 09:59:42

And a Dake engraving that seems to be very close to the Dake I purchased.

Edited By PatJ on 28/12/2022 10:00:15

Ches-

Thanks for the great link.

It took me a long time to figure out how this little engine works, and I actually had to disassemble my dad's engine and study it for quite some time.

Here are a few sketches I created in order to understand this engine.

Edited By PatJ on 28/12/2022 10:09:16

Now that is different. Bit of a workout trying to imagine it in motion. Fascinating to say the least!

Pat,

Thanks for the explanation of 'how it works'. Still wrapping the grey matter round it but I'll get there.

I wonder what clue/need led the original designers to the engine layout? I now know it was compact and powerful, maybe suffered a bit from steam leakage and used about 100psi (...is that a typical pressure for the day?).

Cheers,

Ches

One was made and written up for model engineer just a few years ago.

Pat,

Your dad was cleverer than most.

I have heard some describe this engine as a Wankel-type affair, but I think a Wankel had a single rotor, or perhaps a couple of rotors in line.

The Dake has a piston inside of another piston, but otherwise the pistons get pushed from the top and sides, similar to how a Wankel works, sort of.

The clearance between the crankcase cover and the pistons was controlled by using stacked gaskets, perhaps each at 1/1000 thick.

I don't think leakage was a problem.

There was no adjustable cutoff, and so this would not necessarily be an economical engine to run at full speed continuously, but as a specially adapted engine that required quick reverse and no dead centers, it is an exceptional design.

These engines run extremly smoothly, and make an odd slushing sound when they run.

No doubt they make perhaps a constant torque as they revolve, similar to a 3-phase electric motor.

They were advertised as having only three moving parts, which is almost true.

The flywheel, crankshaft, crank disk, and crank pin are considered on part (assembly).

The inner piston is the second part, and the outer piston and its two shoes are the third part (assembly).

From a parts count, it is an absurdly simple design.

From a theoretical functional standpoint, the engine is pure genius (the genius of Roots originally, modified a bit by Dake).

The inner piston is also a rotating multi-port slide valve.

I find this a fascinating engine, and for me to find one on ebay is sort of like finding the Hope diamond laying out in the front yard. I have never seen one of these engines for sale.

The totally enclosed design is a turn-off for some, who like to see the moving internal parts of an old engine.

.

Yes, that fellow used my Dake drawings as a reference in order to figure out how to build his.

He asked me if he could use my drawings, and I told him no, but requested that he instead use the concept from my drawings, but make his own drawings and somewhat unique Dake engine, and so he did.

.

Edited By PatJ on 28/12/2022 10:41:40

Dad definitely had a gift for figuring out how obscure old engines functioned.

This was one of several very odd engines that dad built, that I had to disassemble in order to understand.

.

Very kewl

Have prayed to the God Hermes that your friend will arrive, good luck

Smokstack says the engine was popular for steering engines and winches. Although compared to a round piston it must be inefficient due to leaks and friction, the thread mentions some important advantages:

• There's no dead-centre so it always starts
• Easy to reverse
• Flat compact format
• Low vibration

I guess the Dake was a good idea in it's day but later developments led to other engines doing the same job more efficiently.

Dave

I sent the seller an email, and requested that he be sure to pack the engine to be shipping-proof.

I have had heavy items that where packed lightly, and so they broke out of their box and were lost forever.

It would be a tragedy to have this engine lost in shipping, but I don't have time to go pick it up, so we pray to the shipping gods that they show mercy upon us.

.

Some other advantages I have heard are the totally enclosed crankshaft keeps dirt and water out of the engine.

I saw one Dake on the front of a ship, used to hoist the anchor.

Another application was down in the bottom of a mine, where the dust could damage an open engine.

And the reversing valve could easily be installed remotely, such as at the top of the mine shaft.

Best I can tell, these were hard working and higly functional engines, in spite of being rather unorthodox in design. Better for occasional use I think than continuous loads.

And one last thing I read was that the wear on the inner piston was non-linear, since the outer ends of the piston moved at a higher velocity than the center of the piston.

They sold a lot of these engines though, and built them I think up into the 1950's, so it was a very successful and functional design for certain specialized applications.

Here are a few photos that someone allowed me to use.

This engine is in a museum up north.

And some engravings for an overhead hoist, and a steering engine.

Edited By PatJ on 28/12/2022 11:16:20

Edited By PatJ on 28/12/2022 11:18:13

I was getting ready to cast a Dake in gray iron.

I may have to rethink.

Edited By PatJ on 28/12/2022 11:26:42

What an education, thank you.

The Dake reversing valve works similar to how a Westinghouse locomotive brake control works.