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

[Salty Sea Dog]

Is there a way for you to regulate the springs' seat pressures? How do you figure out how much you need to prevent valve floating? This is so amazing and I can hardly wait to see it running! Very, very nice!!

[michael mott]

Buck, I have no Idea. This is all trial and error. I am flying by the seat of my pants on this one.

 

Michael

[cog]

Hold on to those pants, Michael, you're doing rather nicely ... The wire you use for the springs, anything special?

[druxey]

Looking at the photos, it took me back some 50 years to replacing the side valves in a four-cylinder 'sit-up-and-beg' Ford engine after re-grinding the valve seats. Getting those split retainers back in place against spring pressure was a miserable task! Thanks for the memory, Michael.

[michael mott]

Thanks again for the likes.

 

Carl the springs are made from some .011"  diameter music wire which is number 2 music wire gauge, incidentally I have 3000 feet of the stuff, I bought a 1lb roll of it back in 1970 for the wire trusses on a 1/4 scale model of the Bleriot 11 the first plane to cross the English Channel.

So if anybody needs some let me know..

 

Druxey glad I was able. These ones were more fiddly than miserable.

 

Michael

[realworkingsailor]

Hi Michael,

 

An option you may want to consider, have a look at the brush springs for a DC-71 (Pitman) motor:

 

Andy

[michael mott]

Hi Andy

Thanks for the tip.

 

Michael

[Jack12477]

1/4 scale model of the Bleriot 11 the first plane to cross the English Channel.

 

Michael, there's a full sized original across the river from me in the Old Rhinebeck Aerodrome - flys most weekends every summer in their air shows. It's only one of many WW I aircraft.

 

   Bleriot XI (Original)

Country: France

Year: 1909

Engine: Anzani

Horsepower: 35

Wingspan: 25′ 7″

Top Speed: 47 mph (75 km/hr)

Gr. Weight: 661 lbs (300kg)

Current Status: Active

 

Bleriot XI “Cross Country” (Original)

Country: France

Year: 1911

Engine: Gnome Rotary

Horsepower: 70

Wingspan: 25′ 7″

Top Speed: 47 mph (75 km/hr)

Gr. Weight: 661 lbs (300kg)

Current Status: Static Exhibit

[michael mott]

Hi Jack, I studied, that aircraft along with the one from Old Warden in England. my model had wing warping as well.

 

I never finished it and gave it to the local air museum, along with all the drawings and research photographs, the drawings were from Old Rhinebeck.

 

here are a few shot which is all i have.

 

 

 

 

I was particularly pleased with the "canework" on the seat. the bentwood was formed from layers of birch veneer formed over a bent piece of stainless steel. After the layers had cured for about a week i filed and sanded the laminate to shape.

 

 

The canework was woven from some plastic bag material from a local shoe shop, it had just the right tan colour. I cut strips of the plastic about 1/16th wide then stretched it out until it reached it limit of elasticity, it was then reduced in width to about 1/32 and had a slight convex cross section. it took two tries to get the weaving right, and the toughest part was keeping the strands all the same way up with the curve of the "Cane" on the top side.

 

This would be a great way to make one of those cane seats in one of the Adirondack Guide boats

 

 

Michael

 

 

[Jack12477]

I take it you have visited Old Rhinebeck in person then ?

[Twister]

Michael,

 

At least with that little bit of spare music wire you can afford to keep trying until the spring is 'right' !!

 

Seeing those pictures of the Bleriot brought back many memories - it was the first (static) model aeroplane that I built, must have been about 30 years ago, from a kit using matchsticks. It survived all of 3 weeks after completion when our dog thought it looked eminently chewable. I never did build anything from matchsticks again...

 

Row

[michael mott]

Jack, no I have not been there it was all by correspondence.  I have and old book on aeronautical engineering with an introduction in it by Orville Wright.

 

It is "Practical Aeronautics" by Charles Hayward published by the American Technical Society in 1917 first published in 1912, it has the complete plans for building the Bleriot, along with lots of photographs as well. I used it as my main source.

 

Row, I am already on it. I made all new springs and new keepers that were just .002" smaller in diameter on the small diameter which allowed the springs to slip over them more easily. I am just in the process of jigging up my Dremel shaft into a fitting that I can hold in the lathe tool post so that I can accurately cut the facets for the valve seat cutter.

 

On the week end I saw a micro drill like one of these there was absolutely no vibration and it had a fabulous chuck. something like this is now on my wish list.

 

Michael

[Jack12477]

Michael,

 

Nice photos of the plane! Nice cane chair ! Yes, I would die for one of those old Adirondack guide boats, they are beautiful as well as practical.

 

If you ever get the chance to come East, you should plan a trip to the Aerodrome. They fly that Bleroit every weekend, mostly an "Orville Wright" kinda flight - 10 feet off the ground and just the length of the field - very impressive to watch.  Cole Palen, the founder, built a replica of a Fokker tri-wing (DR-7 if my memory is correct), the engine and prop are original -  the rest of the plane he scratch built from original plans he found in an archive in Germany.  He used to fly it as the "evil Black Baron" (until his death some years back) in their airshow every Sunday. Airshow is very impressive.

 

I'm planning on taking my 9 yr old granddaughter to one of their shows this summer when she comes for a visit. She's at the age where she will appreciate it.

 

Love your little engine ! Magnificent workmanship! Looking forward to seeing it run.

[michael mott]

Thanks for all the kind comments. It was neat to go back down memory lane on the Bleriot.

 

My tool for the Dremel seemed to work OK The shaft is a really tight fit into the 23/32" hole, I will add a locking screw for security for future work. it did work well shaping the cutting faces on the valve seat cutter.

 

 

I have done the first seat, and then I needed to make a new split holder for the valves so that I could machine them to length, I decided to make the holder the exact length of the valve stem so that it would be easy to slip the valve in then trim off the excess, it worked fine for the first one, the second valve would not slide through the same as the first.

 

Now I understand the Go- No-go gauges and what such a small difference at a couple of tenths of a thou make.  I ended up fiddling with it for a couple of hours, and working on the valve polishing off the offending .0002" which was not easy, I probably could have made a new valve in the same time, but did not want to reset the tooling.

 

the valve seat cutter worked well but slower that I thought it would. cutting the bevel from .093" to .120" diameters

 

 

The new springs are better.

 

 

I will take some pics today of the cutter and of the slit holder to the valves

 

Michael

 

 

 

 

[popeye the sailor]

nice work on the springs Michael!  are the valves seated flush in the head?   since the valves are on the same 'plane' as the pistons,  the only thing to be sure of,  is that there is enough clearance for their actuation.  some seriously good metal work going on!

[michael mott]

Thanks for the visits and likes.

 

Denis, the valves are just shy of the surface now and I am thinking that I need to change the amount of rise on the camshaft lobes.

 

The valve seats look so rough at this magnification I am working on sorting out how to lap the valves and  the seats

 

 

 

The tiny clearances at this scale are beginning to concern me.

 

Valve open

 

 

valve closed

 

 

I think it needs to open about 15 thou more. Oh well what's one more change, and it probably wont be the last

 

 

Michael

[mtaylor]

I think a bit more lift on the cam, Michael. You can more since this is a flathead, the head area can always be machined a tad.   For lapping, I'd think some valve lapping compound maybe followed by some jeweler's rouge.  One suggestion, though, on whatever way you do it... number the valves and the valve seats.  Once their lapped, do not swap them. 

[druxey]

Oh, yes. The lapping compound and jewellers' rouge routine... I remember it well. 

[cog]

Lucky me, a mini only had 8 valves, and these are far, far larger ...

[kees de mol]

It's a real beauty. Thank you for the photo's and for sharing them.

[popeye the sailor]

I remember when my father seated valves........he used a compound and a suction disc on a stick.   he put the compound on the valve seat,  and the disc on the head of the valve,  and rub the stick in his hands,  making the valve spin back and fourth.   made them fresh as a daisey    I'm sure it can be found at any auto parts store.    true what Mark says......once this is done though,  they will become mated to their position.   what your thinking sounds right,  although I couldn't even guess at a spec at this scale.   does this mean another cam is on the drawing board?  once this engine is running,  it will create it's own intake and exhaust pressures.........it'll start eating and breathing on it's own       It's ALIVE!!!!  heir Frankenstein....no......it's Fraunkensteen

[chevygrunt]

Hi,

Having a small amount of lapping experience. I would be careful with using a grinding/lapping compound between the valves and the brass.

As I understand it, certain types of lapping use a soft and hard material. The soft material is the lapping tool and the harder material the work piece. When the compound is applied it beds into the softer material and forms a fine abrasive surface which then works to remove material from the work piece. In your application, I would hate to see the brass become embedded with grit which could be difficult to remove after seating the valves.

Most modern day car heads have hardened seats, so it isn't such an issue.

I am not an expert in this and would happily be corrected.

 

An excellent job by the way. As a machinist, I can fully appreciate what you have achieved! Well done!!

Cheers, Scott.

[michael mott]

 

I would be careful with using a grinding/lapping compound between the valves and the brass.

Scott thanks for this insight, perhaps a valve set up as a burnisher that could be used as a polishing burr instead of cutting the angle polishing it.

The other option would be to add some drill rod valve seats........no I'm not going there.

 

Mark thanks for the tip about keeping the valves in their respective seats, and I will raise the cams so I will have to make some new ones.

 

Denis the suction cup will need to be replaced with some form of adhesive at this diameter

 

'Tis snowing again today so a good day to be in the shop.

 

Michael

[cog]

Michael,

 

I recall on my mini the valve had a valve seat, a ring in the engine head, maybe an option to insert a hardend metal ring ... just a thought

I also use double valve springs ... but then ... it was an engine to be run at high rpm's

[michael mott]

Thanks to all for the feedback on the valves.

 

today I revisited the drawings and made some measurements of the cams and I am going to do a couple of different things before making new cams.

 

First I skimmed .010" off the top of the head this cleaned up the difference between the cylinder liners and the head as well. I did some checking on the engine sites and the practice seems to be to leave the stock that the valve is turned from long enough to use the top as a handle to do the lapping after the valve is lapped then it is parted off from the stock. I am also going to burnish the valve while it is still on the stock, this will ensure that most of the polishing will happen on the brass.

 

I am also going to raise the position of the keeper about .050" this will give a little more pressure on the valve when closing and keep the keeper above the crankcase more.

 

Thanks for all the likes as well.

 

Michael

[michael mott]

Spent the evening turning up the new valves.

 

 

 

decided that the flywheel might be a good way to spin the valves

 

 

 

after the valves were lapped I parted them off

 

 

then completed the rest of the turning.

 

 

popped in the new springs and the old keepers.

 

 

tomorrow I will cut the new lifters.

 

Michael

 

 

 

 

[Jim Lad]

I've been following along, Michael, but all this detailed engineering is a bit beyond me - delightful work, note the less!

 

John

[Bedford]

I think the use of the flywheel is inspired, I love "out of the box" thinking and that's a classic example!

[popeye the sailor]

they look super Michael.   when I saw them with the slots in the faces,  I immediately thought that a screwdriver could be used instead of an suction cup 

 

very nice!

[druxey]

Sure beats a miniature plunger for lapping in the valve seats! Good stuff.