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Skipjack by michael mott - 1/8th scale - SMALL - 19 foot open launch


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Am I to assume from the pics of the real engine that it has a total loss lubrication system, ie the oil pot on top of the engine?

 

If so I imagine that would simplify things too because it won't have an oil pump.

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Carl, Steve thanks for stopping by.

Steve I think that you are correct but I need to learn more about these old engines. This site has some interesting engines the one I linked to has cylinders that are 3/8th bore by 1/2 stroke which is very encouraging.

 

Michael

Current builds  Bristol Pilot Cutter 1:8;      Skipjack 19 foot Launch 1:8;       Herreshoff Buzzards Bay 14 1:8

Other projects  Pilot Cutter 1:500 ;   Maria, 1:2  Now just a memory    

Future model Gill Smith Catboat Pauline 1:8

Finished projects  A Bassett Lowke steamship Albertic 1:100  

 

Anything you can imagine is possible, when you put your mind to it.

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Looks like there will be a wealth of knowledge there.

 

Will you make your own spark plugs? I have a contact of a bloke who sells them, not sure if they are small enough though.

 

Steve

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You should have lots of fun building that engine.

 

Bob

Every build is a learning experience.

 

Current build:  SS_ Mariefred

 

Completed builds:  US Coast Guard Pequot   Friendship-sloop,  Schooner Lettie-G.-Howard,   Spray,   Grand-Banks-dory

                                                a gaff rigged yawl,  HOGA (YT-146),  Int'l Dragon Class II,   Two Edwardian Launches 

 

In the Gallery:   Catboat,   International-Dragon-Class,   Spray

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Hi Steve, yes I am going to make my own, yesterday I went to the city to a large model supply store, I was disappointment with the answers to the questions I had regarding spark plugs and basic information about model engines. I also asked about book and was told that there is this thing called the internet. I did save the trip by purchasing some 3/8 dia 6061 aluminum alloy and some 1/2 inch diameter stainless steel rod. came home and looked up "how to make miniature spark plugs" on the web   that was how I found that model engine site.

 

I stayed up way too late reading as much as my eyes would allow but now feel much better about the decision to build a proper engine for Skipjack.

 

Thanks for all the likes.

 

Michael 

Current builds  Bristol Pilot Cutter 1:8;      Skipjack 19 foot Launch 1:8;       Herreshoff Buzzards Bay 14 1:8

Other projects  Pilot Cutter 1:500 ;   Maria, 1:2  Now just a memory    

Future model Gill Smith Catboat Pauline 1:8

Finished projects  A Bassett Lowke steamship Albertic 1:100  

 

Anything you can imagine is possible, when you put your mind to it.

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Hi Bob I must have been writing when you posted. Yes it will definitely pose a few challenges but isn't that what these hobbies are really all about. Research, figuring out how something was built, testing  materials for our models, choosing a method to make some small item, sharing our discoveries. the joy of completing a part that meet our expectations.

 

While I have been researching this engine piece I have been ruminating in the back of my mind the specific choices and way that the ribbands will be made, even though they will be temporary they need to be strong enough to withstand the pressures of the bent ribs.

 

One thing that I am contemplating is to use thinner ribbands but laminate a few layers, because the outside dimension can be larger as long as the inside one conforms to the inside shape of the planking. If they are too flexible it will make fitting the ribs much more difficult. 

 

In my "Boatbuilding Manual 4th edition" by Robert M Steward  book, in the section that covers the preparation of the molds for building the hull it recommends that the ribbands be full length of the hull if possible and only use a join if needed at the least curved part of the length.

 

My ribbands can be cut from material that is only 32 inches in length so the joining longitudinally is not an issue. I do not want to put a lot of bending stresses on the thin plastic bulkheads so by making them thicker by laminating layers might prove to be the best option. I will be tying them to the bulkheads with very fine copper wire which should not interfere with the layers. 

 

Michael 

Current builds  Bristol Pilot Cutter 1:8;      Skipjack 19 foot Launch 1:8;       Herreshoff Buzzards Bay 14 1:8

Other projects  Pilot Cutter 1:500 ;   Maria, 1:2  Now just a memory    

Future model Gill Smith Catboat Pauline 1:8

Finished projects  A Bassett Lowke steamship Albertic 1:100  

 

Anything you can imagine is possible, when you put your mind to it.

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I would have made the bulkheads smaller and bent the ribs on the outside of the ribbands.  I don’t know how to plank with the ribs on the inside.  I’ll have to watch and learn.  I do that a lot.

 

Bob

Every build is a learning experience.

 

Current build:  SS_ Mariefred

 

Completed builds:  US Coast Guard Pequot   Friendship-sloop,  Schooner Lettie-G.-Howard,   Spray,   Grand-Banks-dory

                                                a gaff rigged yawl,  HOGA (YT-146),  Int'l Dragon Class II,   Two Edwardian Launches 

 

In the Gallery:   Catboat,   International-Dragon-Class,   Spray

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Bob my understanding from Steward is that as the planks are going to be placed the ribbands are removed one by one as the planking proceeds. the link is to a series of pictures showing the method.

 

Michael

Current builds  Bristol Pilot Cutter 1:8;      Skipjack 19 foot Launch 1:8;       Herreshoff Buzzards Bay 14 1:8

Other projects  Pilot Cutter 1:500 ;   Maria, 1:2  Now just a memory    

Future model Gill Smith Catboat Pauline 1:8

Finished projects  A Bassett Lowke steamship Albertic 1:100  

 

Anything you can imagine is possible, when you put your mind to it.

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That’s an interesting method, I’ll watch and see how you like it.

 

Bob

Every build is a learning experience.

 

Current build:  SS_ Mariefred

 

Completed builds:  US Coast Guard Pequot   Friendship-sloop,  Schooner Lettie-G.-Howard,   Spray,   Grand-Banks-dory

                                                a gaff rigged yawl,  HOGA (YT-146),  Int'l Dragon Class II,   Two Edwardian Launches 

 

In the Gallery:   Catboat,   International-Dragon-Class,   Spray

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Making the spark plugs and all, you're a better man than I Gungadin !

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I have been doing some research into the whole engine building aspect of this little launch. I made the top part of the engine this evening it still need a bit more work to add the top plat to seal in the water cavity the spark plugs will thread through the plate into the main body thereby allowing water to circulate around the part that goes through the cavity.

 

This drawing shows the section through the engine and sections through the cylinder head.

 

post-202-0-72069800-1414736199_thumb.jpg

 

Buffalo 3HP sheet 1.pdf

 

this is the top part of the head

 

post-202-0-76765100-1414736198_thumb.jpg

 

Buffalo 3HP sheet 2.pdf

 

And the brass part I made today

 

post-202-0-76805500-1414736200_thumb.jpg

 

post-202-0-75856200-1414736201_thumb.jpg

 

post-202-0-49711200-1414736202_thumb.jpg

 

Michael

 

 

Current builds  Bristol Pilot Cutter 1:8;      Skipjack 19 foot Launch 1:8;       Herreshoff Buzzards Bay 14 1:8

Other projects  Pilot Cutter 1:500 ;   Maria, 1:2  Now just a memory    

Future model Gill Smith Catboat Pauline 1:8

Finished projects  A Bassett Lowke steamship Albertic 1:100  

 

Anything you can imagine is possible, when you put your mind to it.

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I know it is 1:8 scale but I didn’t expect it to be so small.  Fine work.  The guys on the model engine forum are very helpful.

 

Bob

Every build is a learning experience.

 

Current build:  SS_ Mariefred

 

Completed builds:  US Coast Guard Pequot   Friendship-sloop,  Schooner Lettie-G.-Howard,   Spray,   Grand-Banks-dory

                                                a gaff rigged yawl,  HOGA (YT-146),  Int'l Dragon Class II,   Two Edwardian Launches 

 

In the Gallery:   Catboat,   International-Dragon-Class,   Spray

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Thank you for all the likes, And Bob and Steve for your comments, its been a long couple of days fiddling with some finicky numbers, I had to make a couple of small modifications to my Mill Drill so that I could use some dial verniers as read out dials for the table travel. I had already set up the depth one a few years ago and because I have slip dials on the mill I have been able to manage up until now . However machining these tiny dimensions with a centre Zero was challenging to say the least. so now I can clip in the vernier and use it as a poor mans DRO (digital read out, only this is an Analog read out :rolleyes: )

First I cut a piece of 1 inch square brass and then re cut it to 1.375 x 1 x .625 inches the first task was to bore the main holes to form the inside of the water jacket shell these are .625 diameter and almost 5/8 deep. then bored the holes that will mate with the combustion chamber in the top piece. After the big hole were machined I flipped it over to reduce some of the metal and then machines the small holes for the valves and water passages to the top part of the head.

Next I made a couple of support keepers out of some 3/4 diameter brass rod to fill the bore holes and reduced the diameter at the top to use as location stubs for the top part this also allowed me to thread some 10 - 32 cap screws through the spark plug holes  to hold the whole shebang together. after the inlet and exhaust ports were machined which seemed to take forever, I was finally able to get on with some finish filing.

 

 

post-202-0-67178500-1414994442_thumb.jpg

 

I like to have a ground safe edge on some of the files it really helps to keep things square

 

post-202-0-04287700-1414994444_thumb.jpg

 

The parts are beginning to look like the top of the engine.

 

post-202-0-11330400-1414994445_thumb.jpg

 

The valve rods will be fabricated from some largish sewing needles these are .046 inches in diameter which works perfectly, they obviously need some work yet.

 

post-202-0-42345000-1414994446_thumb.jpg

 

Time for a break.

 

Michael

Current builds  Bristol Pilot Cutter 1:8;      Skipjack 19 foot Launch 1:8;       Herreshoff Buzzards Bay 14 1:8

Other projects  Pilot Cutter 1:500 ;   Maria, 1:2  Now just a memory    

Future model Gill Smith Catboat Pauline 1:8

Finished projects  A Bassett Lowke steamship Albertic 1:100  

 

Anything you can imagine is possible, when you put your mind to it.

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Steve just plain old "elbow grease" files , wet and dry 400, 600, and steel wool. The files are what do bulk of the work. The hard brass might also contribute. 

I notice that some brass is more yellow and gummy. This brass is nice to machine and work with hand tools.

 

Michael

Current builds  Bristol Pilot Cutter 1:8;      Skipjack 19 foot Launch 1:8;       Herreshoff Buzzards Bay 14 1:8

Other projects  Pilot Cutter 1:500 ;   Maria, 1:2  Now just a memory    

Future model Gill Smith Catboat Pauline 1:8

Finished projects  A Bassett Lowke steamship Albertic 1:100  

 

Anything you can imagine is possible, when you put your mind to it.

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Sweet machining.  This is right up there with the goodies at:  http://www.craftsmanshipmuseum.com/index.html

Mark
"The shipwright is slow, but the wood is patient." - me

Current Build:                                                                                             
Past Builds:
 La Belle Poule 1765 - French Frigate from ANCRE plans - ON HOLD           Triton Cross-Section   

 NRG Hallf Hull Planking Kit                                                                            HMS Sphinx 1775 - Vanguard Models - 1:64               

 

Non-Ship Model:                                                                                         On hold, maybe forever:           

CH-53 Sikorsky - 1:48 - Revell - Completed                                                   Licorne - 1755 from Hahn Plans (Scratch) Version 2.0 (Abandoned)         

         

                                                                                                                                                                                                                                                                                                

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Very impressive, Micheal.  Very impressive.  I can't imagine working to that precision on something so small - or even something large.

 

I am catching up a bit with your posts.  I agree very much with the idea that satisfaction comes from working out solutions to the many different problems we face in this craft.  If it were not for those challenges in research, planning, testing ideas, etc. building these models would be much less engaging - for me at least.

 

I agree with the person who recommended ribbands in one long length.  I pieced the ribbands near the stern on YA and regretted it.  Its very easy to introduce discontinuities into the curve.  One piece, uniform thickness, straight grain - important factors.

 

Laminating the ribbands should give their curve more set - ie make them stifferand less resistant to flexing.

 

Great work. Fascinating.

 

Ed

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Thank you all for the likes.

Brian, Jack, Mark  thanks for the kind comments.

Ed the more I think about laminating the ribbands the more I like the idea.

 

I discovered that at this small scale there is little room for error. When I removed the support plugs today after finishing the shaping and a few more holes for the water inlet and inspection hole in the front side, I saw that the port holes had in fact penetrated the wall of the water jacket. the space inside the jacket is large enough that I decided to add a plate that will get sweated in place.

 

the first picture shows the two crescent shaped holes from the port drill breaking through the wall.

 

post-202-0-62803300-1415083052_thumb.jpg

 

The sleeve insert is machined from some  hard 3/4 brass rod the wall thickness was .020"  I sliced off two rings then cut those further to just fit enough that the curve is slightly greater than half the diameter inside. By doing it this way they are snug enough that they do not fall out.

 

post-202-0-63738900-1415083053_thumb.jpg

 

The next picture shows the inspection hole which still need cleaning up and the cylinder liner positioned to show the water circulation cavity. I will make the base plate before the liners are finalized. It has occurred to me that I will need a pretty good filter system to keep any debris out of the water system.

 

post-202-0-56161400-1415083054_thumb.jpg

 

The next photo shows the top of the cylinder with the head removed the holes still need to be reamed 13/32 for the stainless liners. I am still contemplating making these two parts able to be separated I think I have enough space to add some small long bolts up through the water jacked that way they would be hidden.

 

post-202-0-66800200-1415083055_thumb.jpg

 

post-202-0-64800300-1415083056_thumb.jpg

 

I think I need a break from metalwork and do a little whittling of the boxwood stem and sternpost.

 

Michael

 

 

Current builds  Bristol Pilot Cutter 1:8;      Skipjack 19 foot Launch 1:8;       Herreshoff Buzzards Bay 14 1:8

Other projects  Pilot Cutter 1:500 ;   Maria, 1:2  Now just a memory    

Future model Gill Smith Catboat Pauline 1:8

Finished projects  A Bassett Lowke steamship Albertic 1:100  

 

Anything you can imagine is possible, when you put your mind to it.

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Looking absolutely beautiful, and the decision to go w/ jump spark and buzz coil should make it (relatively ;)) straight forward. 

 

Are you going to use Macor for the plug insulators?

 

One question: The bronze sphere on the 1:1 engine just aft of the block--is that a vacuum accumulator?

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Bob, I read somewhere that it is to reduce water hammering. i cannot find the reference right at the moment though.

 

Thanks to all for your kind remarks and for all the likes.

 

Michael

Current builds  Bristol Pilot Cutter 1:8;      Skipjack 19 foot Launch 1:8;       Herreshoff Buzzards Bay 14 1:8

Other projects  Pilot Cutter 1:500 ;   Maria, 1:2  Now just a memory    

Future model Gill Smith Catboat Pauline 1:8

Finished projects  A Bassett Lowke steamship Albertic 1:100  

 

Anything you can imagine is possible, when you put your mind to it.

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your progress is really awesome Michael!

I yam wot I yam!

finished builds:
Billings Nordkap 476 / Billings Cux 87 / Billings Mary Ann / Billings AmericA - reissue
Billings Regina - bashed into the Susan A / Andrea Gail 1:20 - semi scratch w/ Billing instructions
M&M Fun Ship - semi scratch build / Gundalow - scratch build / Jeanne D'Arc - Heller
Phylly C & Denny-Zen - the Lobsie twins - bashed & semi scratch dual build

Billing T78 Norden

 

in dry dock:
Billing's Gothenborg 1:100 / Billing's Boulogne Etaples 1:20
Billing's Half Moon 1:40 - some scratch required
Revell U.S.S. United States 1:96 - plastic/ wood modified / Academy Titanic 1:400
Trawler Syborn - semi scratch / Holiday Harbor dual build - semi scratch

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Wow!!

 

What more can be said?

 

I've always liked the idea of building a small 4 stroke engine, so I'll be paying particular attention to this log. Having just acquired a lathe I think I'm rather a long way off having the requisite machining skills to attempt anything like this yet - I'm currently focusing on making huge amounts of swarf.

 

Your workmanship is, as always, superlative!

 

Regards,

 

Row

1:28 Scale J class yacht 'Enterprise' (R/C)

Build log currently at: http://www.rcsailing.net/forum1/showthread.php?6264-1-28-J-Class-Enterprise-build-log

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I expect that I will never build a miniature engine, much less a working one, in my modeling lifetime, but I am immensely enjoying following your work.  

 

That was a truly elegant and practical solution to your slip.

 

Dan

Current build -SS Mayaguez (c.1975) scale 1/16" = 1' (1:192) by Dan Pariser

 

Prior scratch builds - Royal yacht Henrietta, USS Monitor, USS Maine, HMS Pelican, SS America, SS Rex, SS Uruguay, Viking knarr, Gokstad ship, Thames River Skiff , USS OneidaSwan 42 racing yacht  Queen Anne's Revenge (1710) SS Andrea Doria (1952), SS Michelangelo (1962) , Queen Anne's Revenge (2nd model) USS/SS Leviathan (1914),  James B Colgate (1892),  POW bone model (circa 1800) restoration

 

Prior kit builds - AL Dallas, Mamoli Bounty. Bluejacket America, North River Diligence, Airfix Sovereign of the Seas

 

"Take big bites.  Moderation is for monks."  Robert A. Heinlein

 

 

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Michael,

 

Looks stunning, as all your metal working has been here at MSW so far. I presume you make it a runnung engine ... any reason for using brass instead of iron, aluminium, etc?

Carl

"Desperate affairs require desperate measures." Lord Nelson
Search and you might find a log ...

 

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Denis ,Row, Dan, Carl, thanks for looking in and for the kind words. 

 

I am beginning to wonder about this engine business.

 

The three cylinder blocks so far!

 

post-202-0-41943100-1415502688_thumb.jpg

 

The one in the middle was the first one I was getting more dissatisfied by the hour, because the little break through into the water jacket area was nagging at me all the time. It was actually the second of the things that was bugging me and the top part had its own error I realized the oval water area was too long. also I decided that the bottom mounting lugs needed to be an integral part instead of part of a plate that was going to be fitted to the bottom somehow?

 

So I started over and was merrily milling down into the water jacket area when saw the cutter making it way down the outside of the jacket....... yup I set the cuts on the mill from the wrong side of the block after working the outside dimensions.

 

you can see the clean little slot on the one in the back, right down the middle.

 

The one in the front is version number three, according to folk lore it should be lucky.

 

post-202-0-56476100-1415502689_thumb.jpg

 

The most tricky part was drilling the inlet and exhaust holes (still a bit gun-shy after the first mistake) I had to set the block up with a compound angle, for each hole the inlet ones on the outside and the exhaust ones in the middle. Now the hand work filing the surface shapes is under way. I also increased the size of the valve heads to .125 from .093 inches. The bore of the cylinders is reduced to 5/16 from 3/8ths in order to get more space for water circulation.

 

post-202-0-65020800-1415502690_thumb.jpg

 

Carl in answer to your question why brass instead of iron, it is because brass is easier to work and I have the material. I have noticed that some of the engines on the engine website are brass and they seem to run fine as long as there is a steel or iron liner and an aluminum piston. this is the route that I am following.

 

Michael

 

 

Current builds  Bristol Pilot Cutter 1:8;      Skipjack 19 foot Launch 1:8;       Herreshoff Buzzards Bay 14 1:8

Other projects  Pilot Cutter 1:500 ;   Maria, 1:2  Now just a memory    

Future model Gill Smith Catboat Pauline 1:8

Finished projects  A Bassett Lowke steamship Albertic 1:100  

 

Anything you can imagine is possible, when you put your mind to it.

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