Redesigned "Leakproof" Elbow Engine

Help Support HMEM:

Ken I

Project of the Month Winner!!!
Project of the Month Winner
Joined
Oct 31, 2010
Messages
1,654
Reaction score
427
Location
Cape Town, South Africa
Here's the completed elbow engine.



And a "prequel" video of it running - I piped up the exhaust so you can hear it without the exhaust noise - but the clatter you can hear is rain on my IBR workshop roof.

You can see the slow running hesitancy at the tight spot which I am hoping to run out before posting a better vid later.

http://www.youtube.com/watch?v=X0-vCBC0KkU&feature=youtu.be

Edit: It now has about 12 hours of run time and will tick over at 50rpm - I'm hoping for 30 or less once the tight spot works itself out.

I set out to design an Elbow Engine that would address some of the problems of the conventional axial flow designs by changing to a radial flow via axle porting. The use of a stiffener joint and slightly flexible "elbows" gets away with most of the alignment issues.

The pistons also rotate on their axles to further reduce running friction as does the inclusion of ball radial and axial bearings.

"O" ring sealed pistons and lip seals on the axles constrain any leakage to the exhaust.

The only oil it "throws" is what makes it past the piston "O" rings and is very little - typically the motor will run for 2 hours before the build up of oil at the cylinder throats becomes heavy enough to start throwing it about.

The G.A.


You can follow the build thread here :-

http://www.homemodelenginemachinist.com/index.php?topic=16790.0

Special thanks to: Captain Jerry, John (Bogstandard), Marv (mklotz), rustyknife, foozer, cutajar, miner49r, dsquire, Arnoldb who all passed comments, made suggestions or simply offered up encouragement – it is all appreciated.

I am trying to upload the design drawings but the uploads section is not cooperating, hopefully Bob will get it sorted, he normally does.

The file will contain a 2D Autocad *.dwg & *.dxf, a single sheet *.pdf and a *.doc file containing over 40 WIP photos and instructions for anyone who's interested.

For now I have attached only the *.pdf because of file size restrictions.

Regards
Ken


View attachment ELBOW6.pdf
 

kustomkb

Project of the Month Winner!!!
Project of the Month Winner
Joined
Dec 14, 2007
Messages
1,181
Reaction score
31

Beautiful job Ken!

Thanks for the great design.
 

b.lindsey

Project of the Month Winner!!!
Project of the Month Winner
Joined
Jan 3, 2008
Messages
2,085
Reaction score
17
Ken, that is one of the best versions of the elbow engine I have ever seen...extremely creative and obviously no sacrifice (indeed improvements) in performance. A one of a kind to be proud of for sure!!!

Bill
 

picclock

Well-Known Member
Joined
Dec 17, 2010
Messages
262
Reaction score
3
That is one very sweet engine - I shall have to stop myself starting one as a project until I have finished the stuff I have on the go. Truly an excellent rethink of the leak issue.

Not sure about the music in the second video .. . ;D

Best regards

picclock
 

ref1ection

Well-Known Member
Joined
Nov 17, 2009
Messages
83
Reaction score
1
Extremely nice rework of the elbow engine and I like your choice of music. ;D

Ray
 

Ken I

Project of the Month Winner!!!
Project of the Month Winner
Joined
Oct 31, 2010
Messages
1,654
Reaction score
427
Location
Cape Town, South Africa
I have posted the drawings as a *.zip file under the downloads section if you are interested.

It contains an Autocad 2D *.dwg & *.dxf file with each part drawn in a different layer / colour.

There is also a single sheet *.pdf of the same.

At this time the downloads section will not accomodate the large (5MB) *.doc file of build notes and photos.

(The download limit seems to be 2.5MB not 25MB as stated)

If you would like a copy of the *.doc file, send me a PM.

Regards,
Ken
 

steamer

Well-Known Member
Joined
Nov 30, 2007
Messages
5,388
Reaction score
28
Nice Engine Ken!

Love the video! Now your going to tell us how you got those camera pans and zooms right?

;D

Dave
 

doubletop

Well-Known Member
Project of the Month Winner
Joined
Mar 1, 2010
Messages
863
Reaction score
80
I like that Ken, great job

Pete
 

Ken I

Project of the Month Winner!!!
Project of the Month Winner
Joined
Oct 31, 2010
Messages
1,654
Reaction score
427
Location
Cape Town, South Africa
steamer said:
Love the video! Now your going to tell us how you got those camera pans and zooms right?
I was wondering how long it would take someone to ask that - and I'd have bet a dollar to a donut it would be you - I also suspect you already know the answer.

Noitoen said:
New design 45º elbow engine. :hDe:
It's possible ! I think ? Maybe ?

Ken
 

steamer

Well-Known Member
Joined
Nov 30, 2007
Messages
5,388
Reaction score
28
Ken I said:
I was wondering how long it would take someone to ask that - and I'd have bet a dollar to a donut it would be you - I also suspect you already know the answer.
It's possible ! I think ? Maybe ?

Ken

;D.....OK so are you going to show it! or do I have to get rough with ya *knuppel2*


;D


Dave
 

Ken I

Project of the Month Winner!!!
Project of the Month Winner
Joined
Oct 31, 2010
Messages
1,654
Reaction score
427
Location
Cape Town, South Africa
O.K. I'll 'fess up - just give me a while to take a photo of the set up.

Ken
 

Ken I

Project of the Month Winner!!!
Project of the Month Winner
Joined
Oct 31, 2010
Messages
1,654
Reaction score
427
Location
Cape Town, South Africa
Steamer,
Here's how I did the camera pans :-



I mounted the camera on a Yaskawa Motoman MH6 DX100 6-Axis industrial robot (one of my showroom machines) normally used for MIG welding (note weld gun tied up out of the way).

Programmed the camera flyby - a very quick and dirty program (10 points) but it worked just fine.

I just played the music in the background as my editting suite is not on speaking terms with my computer for some reason.

Ken
 

steamer

Well-Known Member
Joined
Nov 30, 2007
Messages
5,388
Reaction score
28
That's awesome Ken! I want one of those...for the camera flybys..... ;D

Actually I loved the music!

Dave
 

Captain Jerry

Project of the Month Winner!!!
Project of the Month Winner
Joined
Dec 2, 2008
Messages
971
Reaction score
8
45° Elbow? Not that easy. 135° is a piece of cake but acute angles, while theoretically possible, are not really practical. More than 135° also gets into the silly stuff. I have been there!

Jerry
 

Ken I

Project of the Month Winner!!!
Project of the Month Winner
Joined
Oct 31, 2010
Messages
1,654
Reaction score
427
Location
Cape Town, South Africa
Captain,
Oh Yeah ! - I did a quick cut and paste on Autocad and quickly realised its either going to be a heap of troubles or is flat out not going to work.

Plus a whole new slew of frictional problems.

Possible yes, practical - no.

Ken
 

steamer

Well-Known Member
Joined
Nov 30, 2007
Messages
5,388
Reaction score
28
Ken I said:
Captain,
Oh Yeah ! - I did a quick cut and paste on Autocad and quickly realised its either going to be a heap of troubles or is flat out not going to work.

Plus a whole new slew of frictional problems.

Possible yes, practical - no.

Ken

Based on the fact that two master engine makers can build an Encabulator.....I'd bet they can do a 45... ;D

Dave
 

Ken I

Project of the Month Winner!!!
Project of the Month Winner
Joined
Oct 31, 2010
Messages
1,654
Reaction score
427
Location
Cape Town, South Africa
Ohhhh..... Captain Jerry - did you hear that - first a compliment then a gauntlet is tossed down.

Sorry Steamer but I'm not biting - but I did draw it up.....



Note what happens - the nominal stroke is 30mm @ 90° - the PCD of the cylinders - but when you open the angle to 135° the stroke is radically reduced to 12.53 so the overall "power" of the engine is more than halved - but almost all the frictional problems stay the same.
When you diminish the angle to 45° the stroke increaces to 54.85mm but frictional problems increace. I very much doubt that the pushing cylinder can drag back the exhausting cylinder at an acute angle.

An elbow engine sails perilously close to self locking frictional limits at the best of times.

I believe (I haven't done the math) that deviating from 90° will very rapidly push you "over the edge".

Sorry Dave but that's one challenge I'm not going to pick up.

Regards,
Ken
 

steamer

Well-Known Member
Joined
Nov 30, 2007
Messages
5,388
Reaction score
28
Hey guys,

Ken, I expected nothing less than a full engineering analysis, which you provided. :bow:....The fact that you laid it out tells me you were thinking about it!.....Thanks man!


I will try to make myself worthy in future of the genius that is Ken and Gerry! :bow: :bow:

Dave
 
Top