The Maryak 10

[Maryak]

Hi Guys and Dolls :

What's next some of you asked

After much nashing and grinding of teeth and reviews of our fiscal state, (or lack thereof). The conclusion is that a boiler suitable for my mill engine is beyond my means, at least until after the new house is built and deemed complete by SWMDBO.

In the meantime I have ordered a copy of H Depenbusch's Hit and Miss Engine. It could be some time coming as Plough Books in Oz have it on back order.

In my case idle hands are definitely the devils playground

So looking in my box of useful bits, ((s)crap), box. I probably have enough stuff to build another IC Engine.

Not just any old engine but.......wait for it........

DA DA "The Maryak 10."

Attached is a PDF of the design so far using a rear rotary valve for the inlet and modified, (by me, now there's a worry for a start), Oliver porting for the transfer.

All comments, criticisms, re design parameters, porting, cadding etc. will be gratefully accepted.

Best Regards
Bob

View attachment 10cc.pdf

 

[Kermit]

HUH? What could possible have been written in 1917 that needs to be removed for national security reasons?

Uncle Sam is a little paranoid I think,

Kermit



Let me explain. I was loking for a picture of a model engine I saw that I think shows the kind of engine described when I found that a book had been "Censored"

 

[shred]

HUH? What could possible have been written in 1917 that needs to be removed for national security reasons?

Uncle Sam is a little paranoid I think,
Kermit

I used to have an interesting book, stamped "Declassified" in big letters on it from the WW2-era. Several pages had been cut out of it and there was a similar note to that effect in there as well. The book is like that today, so any scans would show that text as well.

The book was a report was on some early stealth experiments-- putting lights on planes to make them blend into the background sky more (even a bright white plane appears dark when seen against the sky). This in 1943. Makes you wonder what we're up to now.

For Kludge, they tested some prototypes by hoisting silhouettes of planes up above the skyline of some Hawaiian islands and counted the plane-spotter reports, the islanders being a little diligent about reporting planes on the horizon back then.

anyway.. back on topic

 

[Maryak]

Phase 2 of the planning process

OK my first run was metric. Then I realised most of my milling cutters, taps and dies etc were imperial so back to square one. (At least it was a concept showing looks and basic relationships).

Most of yesterday was spent developing the performance of the engine in imperial terms and discovering that I was looking at the engine back to front :

Hence I now have a timing diagram using a FRONT rotary valve for inlet.

The attached PDF shows the timing which, (I hope), has mild porting more for economy than for power.

Best Regards
Bob

View attachment M10Timing.pdf

 

[Metal Mickey]

I will be watching this project with interest. If its like your 3cc you'll have to tie the workshop down!

I like the rotary induction system and will have to make one some time but the projects keep piling up.......anyway good luck. Now I broken my promise to make the last post of the night.......well it is in the UK 233o to be exact.

Metal Mickey

 

[Maryak]

No wonder they pay designers big bucks, I have spent most of the day just trying to get the thing to go together. I think I have success but it was pure genius luck that the holding down cap screws will fit in the space available to them.

I will get there but this Oliver porting is a challenge.

Lots of fun except I have been advised I must be ready to set up the New Year Tree and that will put the kybosh on designers dreaming.

Best Regards
Bob

 

[Philjoe5]

Good luck with this project Bob. I'll be watching for updates. ;D

Cheers and Happy Holidays,
Phil

 

[Maryak]

MM and Phil,

Thanks guys, a PDF to show not very much.

Best Regards
Bob

View attachment 10cc.pdf

 

[Maryak]

Hi All,

Today saw a little more progress and I feel conceptually and proportionally happy. It's almost time to produce some working drawings and start making swarf. First I need a plan view ;D

Best Regards
Bob

View attachment 10cc_2.pdf

 

[Maryak]

Hi Guys,

Well that's Xmas behind us but today is Sydney to Hobart Day and its 16 years since we brought my mates yacht back from Tasmania. Gerry and the Hattricks are having a party

at the skippers home to celebrate his 16 years ownership. Only 2 of the original crew are still sailing, age and health have caught up with the rest of us.

Anyway THE PLAN.

Attached is the General Arrangement from which I should be able to develop working drawings for manufacture of the various bits. I am not sure if it will be the plan or the part which is modified during development, probably a bit of both.

Best Regards
Bob

View attachment Maryak10_3.pdf

 

[Maryak]

Attached is Working Drawing No1. of the Crankcase.

I found myself doing what Paula described as "Machining in her head," whilst drawing this part, that's why it bears only a passing resemblance to what was produced in the general assembly. The changes made are hopefully to make it easier to machine from solid without straying too much from the original.

Best Regards
Bob

View attachment Maryak10_4.pdf

 

[GailInNM]

Looking good Bob, but how did you manage to get TWO days ahead of me. The drawing is dated 28 DEC and it's still only 26 DEC here. ;D
Maybe that is how you manage to get so much more done than I do. Time Shifting.

Gail in NM,USA

 

[Maryak]

Nothing so clever, just looked at the calendar without my glasses ??? ???

Best Regards
Bob

 

[Maryak]

The plans are continuing to be modified and developed along with the machining. :

Sort of a draw as you machine as you draw............................................. ;D

Attached are my latest efforts of crankcase and cylinder.

Best Regards
Bob

View attachment Maryak10_5.pdf

View attachment Maryak10_4.pdf

 

[Maryak]

Good Morning Gentle folk,

This morning I received a very, very informative e-mail from Sandy C concerning the porting of the beast. Now it's time to improve my CAD skills and modify the design to incorporate Sandy's suggestions into the crankcase and cylinder. :bow: :bow: :bow:

I can only say I'm bloody glad the machining is at such an early stage. New cylinder no hassle but new crankcase........................................................S$#t. I am pretty confident Sandy's mods can be achieved using the existing crankcase.

Best Regards
Bob

 

[bentprop]

Hi Bob,I admire your bravery in designing your own engine.You're obviously a lot smarter than I am :big:
I don't know a thing about porting and such,but allow me to make an observation.
On all my IC engines(mostly OS),the intake port is almost the same size as the venturi.Have you made any calculations as to intake size,or just a suck it and see.Your venturi looks quite a bit bigger than your actual port.Will it be able to get enough air in?
Mind you,my engines all have an RC carb. on them,so perhaps that makes a difference.
Am I right in assuming"Oliver porting"is the exhaust on both sides of the cylinder?I'd never heard the term.
I'll follow your project with interest.Regards.Hans.

 

[SandyC]

;D ;D

Hi Guys, and a very Happy New Year to you all.

Bob,

I am so pleased that my e-mail reached you before any major work had been done on the crankcase, especially around the cylinder mounting area.
That was one of the main reasons I sent the info directly to you.... I guess you will need to increase the dia of the lower section of the cylinder a little and make the necessary adjustments to the cylinder bolt PCD etc in order to get the ports and transfer passages in. Hopefully you have more than enough material in your case to easily achieve this, it certainly looks like you have from the photo's.

For you guy's that don't know what is going on.... my apologies for not posting my ramblings regarding this on this thread....I am having quite a bit of trouble with photobucket at the moment....getting lots of unwanted items (hackers) coming into my computer ???...so for the time being I am not using it.....sorry.

I am sure Bob will enlighten you all in the fullness of time.

I look forward to seeing your take on the data Bob.

Best regards to all.

SandyC  ;D

 

[Maryak]

Well, 5 hours later and attached PDF's show the modification to the cylinder and crankcase

bentprop, you were/are spot on and your comments matched Sandy's.

As for my being smart, if I was smart I'd be a millionaire and employ you guys to make my models

I am happy to report that I managed to get the increases in port sizes into the existing crankcase. The non existent cylinder was even less of a hassle.

The transfer and inlet ports are now more than double their previous sizes.

.

Best Regards
Bob

View attachment Maryak10_4.pdf

View attachment Maryak10_5.pdf

 

[Kludge]

Another soul watching the thread with interest ...

I must confess to not knowing anything about 2-stroke engine porting so if some kind soul could help me understand a bit more on the subject, I'd greatly appreciate it.

That aside, I've been watching how you approach the design, Bob. Again, it's utterly fascinating!

BEst regards,

Kludge

 

[kf2qd]

Well there is teh old Cross-Flow, Schneurle, and Perry. At least those are the ones I am familiar with from my model airplane days. Biggest thing to remember is that the exhaust port needs to open before the transfer ports.

Cross-flow had the exhaust port opposite teh transfer port and needed some kind of edam on teh piston to deflect the incoming gases upward into the cylinder to purge the exhaust gases. Schneurle porting used transfer ports close to the exhaust port to create a swirl that efficiently purged the cylinder using a flat piston.

I have a copy of an article that was published in Model Aviation back in the '80s that explained the various porting methods. Still the best work on 2 strokes was done by the Germans in the 1930's... (kind of like the Beamer Boxer)