Author Topic: A New 5cc Aero Diesel Engine Project  (Read 71303 times)

Offline Ramon

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Re: A New 5cc Aero Diesel Engine Project
« Reply #210 on: June 20, 2013, 11:08:55 PM »
Hi 'Guys',

Just a short(?) update on whats been happening over the last couple of weeks and one which will bring this particular engine project  to a close.

Along with finishing the said article on the Mk1and 2 for the ME mag which has now been sent off I've been making parts for a 'Stockton and Jehlik' version of the 15d only this one is correct size - 2.5cc. All the details of this highly modified engine were published in a 1967 Aeromodeller magazine however unlike all the other 5cc versions made so far including an S&J this one is destined to be used as intended and is to be fitted to a replica of S&J's team race model 'Jefe'.

As per the original (modified engine) it utilises some 15d parts, namely the crankcase and piston and liner however though the original also used a standard but slightly modified crankshaft this one had a new one made to suit the prop driver/spinner arrangement.

It's now finished so for those with an interest here are a few pics and captions...

The front bearing housing and backplate. These were machined from a higher spec aluminium (Alumec 89) than the usual 6082
mainly for the fact that the rear valve bearing has no sleeve - how well it stands up remains to be seen.


The induction system differs from the original rotor disc to that of a rotary valve which is still driven by the crankpin extension.


The original crank case. Unfortunately the front and rear faces were well out of parallel by some 0.2mm so after machining the as cast mounting lugs (a considerable fault with the original) true to the exhaust register the case was carefully set up, a very fine cut taken through the bore and all faces brought square and parallel
It had also had the cylinder bolt holes opened to 5BA, one of which was drunken and all slightly out of line to the bore. After setting up to the register for the exhaust flange the holes were opened up to 4BA and threaded ali inserts screwed in with JB Weld. After 24 hours these were re drilled and tapped 6BA - a successful reclamation.


This one is for Per  ;) - it is the composite contra piston - the outer flange is a tight press fit to the liner and the inner moving part - 8.9mm dia - a tight but moveable fit within it


The original article called for a (relatively) large diameter cylinder head with fins of 25 thou thickness and a 25 thou gap cut "with a tool ground from a hacksaw blade". A tool holder was milled up which worked extremely well but unfortunately an attempt to grind side relief into the blade led to the blade disappearing on the first cut. Thereafter the tool had no relief but the rubbing caused pick up which pushed the fins over - as called for they are quite deep 7.9mm.  After 'not a little anxiety' as each fin was achieved - the fourth but last is hanging on by such a small amount it can be deflected quite easily - it did not take much to decide that it should go in the bin. Not only that but cleaning the swarf from the fins proved a real a pain and quickly lead to the realisation that as such, despite the extra surface area, any build up of detritus would soon lead to ineffective cooling anyway.


A decision was made to  do the same as the 5cc version and reduce the number of fins and open the gap. These were cut using a cutter ground from a discarded FC3 cutter shank which allowed some side relief and the whole thing was so much easier.
Incidentally - the bolt holes are put in first - this makes deburring the holes much much easier and is much less likely for the drill to wander when going through separate fins


I think you'll probably agree it was the right thing to do


The crankshaft was turned from En24T but this time (for a first time too) the crankpin was cut from a hardened steel pin and pressed into the web with about .0125mm interference. Again time will tell how this works out


The Prop Driver, Sleeve Nut and Spinner parts. The brass spinner-nose screws into the front of the sleeve nut


The original used the nylon front end of a Cox TD-049 and its venturi/spray bar system. The intake parts here are original Cox but the case is machined from hard plastic.




All parts were given a thorough cleaning .....


.....and it was finally assembled today. The backdrop is a copy of the original 'Aeromodeller' article


and this is it with it's big brother



Well 'Guys' thats the 'Eta' project over  :D and for me time to take a break from machining - (Is that okay Eric? ;))

I guess by now you've all worked out that I'm not a true blue, dedicated, dyed in the wool, model engineer like most of you are but someone who likes a bit of a change from time to time. On that note I'm going to change tack (pun definitely intended  ;)) for a while and do something completely different as plans are afoot to build a Marblehead yacht.
That does not mean to say I'm not intending to make any more engines - theres a couple of Italian beauties waiting in the wings for starters - but needs must  ::)

I would however just like to say a big Thank You to all of you for your kind comments and encouragement throughout this thread - all extremely valued and much appreciated.

On that note then I shall 'slip me cable' for a while and return at some stage refreshed and ready to 'have another go'

Back 'afore too long then - Ramon
« Last Edit: June 20, 2013, 11:23:19 PM by Ramon »
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline tvoght

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Re: A New 5cc Aero Diesel Engine Project
« Reply #211 on: June 20, 2013, 11:31:43 PM »
Ramon,
Thank you for the builds you've shared so far.

 I, for one, would love to see the yacht when it's finished (if not an occasional progress teaser).

--Tim

Offline b.lindsey

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Re: A New 5cc Aero Diesel Engine Project
« Reply #212 on: June 21, 2013, 01:30:33 AM »
I agree Ramon. Don't be a stranger here. Thanks for all your efforts, and sharing these builds.

Bill

Offline bp

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Re: A New 5cc Aero Diesel Engine Project
« Reply #213 on: June 21, 2013, 02:23:00 AM »
Thanks Ramon, a really interesting series of articles/threads,  love the "brothers"....big and small!
cheers
Bill

Online steamer

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Re: A New 5cc Aero Diesel Engine Project
« Reply #214 on: June 21, 2013, 04:30:31 AM »
Thanks Ramon!...do keep in touch and send us a few pics of what your got up to!

Dave
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Damned ijjit!

Online Jo

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Re: A New 5cc Aero Diesel Engine Project
« Reply #215 on: June 21, 2013, 07:18:10 AM »
Best wishes with the model boat Tug. As Dave says looking forward to seeing some photo's of it.

Jo
Usus est optimum magister

Offline Jasonb

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Re: A New 5cc Aero Diesel Engine Project
« Reply #216 on: June 21, 2013, 07:51:41 AM »
Ramon you can't really leave it there, you know we will want to see the S&J when its in the airframe and hopefully in action. ;)

Hope you enjoy the summer of sailing and find your way back into the shop soon.

J

Offline Maryak

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Re: A New 5cc Aero Diesel Engine Project
« Reply #217 on: June 21, 2013, 09:15:49 AM »
Ramon,

Thanks for all your postings here.  :praise2:

Enjoy the sailing.  :whoohoo:

AND

Please remember:

The definition of a "Confident Navigator" is the navigator who can tell you the name and exact lat/long of the shoal your currently suck on.  :LittleDevil:

Best Regards
Bob
Если вы у Тетушки были яйца, она была бы Дядюшкой

Offline sbwhart

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Re: A New 5cc Aero Diesel Engine Project
« Reply #218 on: June 21, 2013, 09:34:46 AM »
Great build Log Ramon  :ThumbsUp: :praise2:

Look forward to see the write up for the ME Mag

And good luck with your boat build I'm sure she will be cracker.

Stew
A little bit of clearance never got in the way

Online Stuart

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Re: A New 5cc Aero Diesel Engine Project
« Reply #219 on: June 21, 2013, 09:36:34 AM »
Thanks for the posts Ramon


I presume that Marblehead will be a model one C I hope , In my dim distance past I used to race one made the sheet winch's  with proportional  feedback ( way before you could by them ) by cannibalising a servo and a mechcarno sp motor that had a variable gearbox

it was an interesting project confused the clubs measurement sec. as I had painted the bumper and they insisted it was over length until i demonstrated the cork number was not part of the hull as per the racing specs ( for those not into sailing length is important )

I seem to remember that the class of Marblehead was to create a model that would fit into the cars of the day

best of luck in your new project please show us the winches if you build them

Stuart

My aim is for a accurate part with a good finish

Offline Admiral_dk

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Re: A New 5cc Aero Diesel Engine Project
« Reply #220 on: June 21, 2013, 07:26:12 PM »
 :NotWorthy:  :NotWorthy: Thank you very much Ramon for your fine article and how-to approach on some extremely fine model engines  :NotWorthy:  :NotWorthy:

Thanks for the info and pictures of the special J&K parts  ;)

I'll agree that the thicker fins with more spacing looks right (better and stronger)  :)

Enjoy your boat trip and as said - don't be a stranger, we all appreciate your work.

Offline Don1966

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Re: A New 5cc Aero Diesel Engine Project
« Reply #221 on: June 21, 2013, 10:20:55 PM »
Ramon it is always a pleasure to read you threads, they are always well constructed and like a class room to learn from. Please return once you have enjoyed your leisure time. I also will be on vacation next week and will be heading for the UK and Italy for two weeks. Enjoy Ramon.

Don

Offline ths

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A New 5cc Aero Diesel Engine Project
« Reply #222 on: June 22, 2013, 07:38:01 AM »
Ramon, I can only echo what has been said regarding your contributions to this forum. Good luck with the Marblehead, I've just given myself a crash course in them (care of google), I'm sure you'll do a fine job of it. Hope we get to see!

Cheers, Hugh.

Offline Ramon

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Re: A New 5cc Aero Diesel Engine Project
« Reply #223 on: June 24, 2013, 09:15:03 AM »
Hi 'Guys' - just caught up with this so as ever thank you for your kind thoughts and good wishes for my coming project.

Obviously it's pleasing to hear you are interested to hear of progress so will pop the odd post on the Chatterbox board as and when.

Re the aircraft Jason - I made the engine as an exercise and a 'thank you' for someone who helped me early on. He's going to make the aircraft and hopefully race it in the relevant events ('Classic' Team Race I think)

I'll pop in from time to time but I do tend to get a bit focussed  ::) so forgive me any long lapses.

One last thing - a bit early but just in case I forget/miss the opportunity.....

Jo - Good luck with your big day at the Guildford Rally. You've certainly prepared for it well so I hope it goes as well for you as it can and that there's lots of interest to reward those efforts. Have a really great time. :ThumbsUp:

Regards to you all - Ramon
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Online Jo

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Re: A New 5cc Aero Diesel Engine Project
« Reply #224 on: June 24, 2013, 09:17:40 AM »
Jo - Good luck with your big day at the Guildford Rally. You've certainly prepared for it well so I hope it goes as well for you as it can and that there's lots of interest to reward those efforts. Have a really great time. :ThumbsUp:

Regards to you all - Ramon

Thanks Tug: I am looking forward to the 22nd July  ;D

Jo
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