A pair of Bugatti Type 50B engines

[Pete J.]

Ok, where to start on this.  First the Tags- I have been following Tim Hodland and Randy D.'s work on there special projects for a while now.  In December I was looking at what Tim was doing and it inspired me to get into a project that has been sitting on my work bench for a while now.  I am not going to go into all the details as that would be an entirely different series of posts, but suffice it to say I have wanted to do this for way the heck to long.

I will not post the entire model here as it is an aircraft but the engines that go into it are a pair of Bugatti racing engines, modified(by Bugatti).  They are type 50 dual overhead, supercharged straight 8 engines.  I have wanted to scratch build them out of metal and their work got me back to the work bench so here is the project.  What you see here is what I have done starting on January 2nd.  This is going to be a long project and the work I am doing can be tedious and take a while so bare with me. There will be updates as interesting things get done.  

 

First off this is all done so far in 7075 aircraft aluminum.  I had to start with the blocks from raw bar stock.

 

I then took another piece of bar stock and milled the basic shape of the valves covers.

 

This shows how the three pieces fit up to form the basic blocks.  This may look like a "V" type engine but it is actually a straight 8.  The "V" section is the overhead cam gear. 

 

 

 

The next part is a coolant pipe that comes out of the head.  This is made by soldering pieces of german silver wire together.  There is a taper to the top piece that was made by heating the wire and stretching it.  The large block of aluminum is a jig for holding the wire while soldering.  I am using a cast resin engine as a basis for a lot of this and you can see the resin part at the bottom.

 

 

The sheet metal covers on most of the top of the engine and valve train are engine turned.  This is the tedious part as each of the "circles' is about .080" with .040" on center.  They are turned into the metal one at a time.  

 

 

This shows what I have done to date.  The engine turning on one engine is done and the coolant pipe is fitted up.  The valve covers are being held in place by wire pins and are not permanent at this point.  I still have a lot of work to do on them with parts to add.  The next operations for the heads are to drill and fit spark plugs and the fasteners that hold the plates in place.  

 

Edited July 20, 2017 by Pete J.
restore photos

[droogie]

Wow! That is taking it to the next level.

[Taxdude]

Very impressive.

[Randy D]

Love this project Pete !!!!!  Much respect for the patience it took to do the engine turned detail my friend.

 

Randy

[Pete J.]

Love this project Pete !!!!!  Much respect for the patience it took to do the engine turned detail my friend.

 

Randy

Randy, Thanks for the kind words and the inspiration.  Some times it just takes a friend to show you the path and get you going.  Thanks again.

[Pete J.]

Fred and Robert, thanks for looking in.  This is going to be a long project with a long way to go.  

[Ace-Garageguy]

Man, THAT is slick. Small scale engine-turning? Too cool. It tries my patience to do that in 1:1.  

[Codi]

Pete....Pete...........Pete.......(did I say Pete?)  finally, you've posted a build / WIP and I must say I'm NOT disappointed, that's fantastic and I love the subject you're tackling.  That turned engine finish is something I'll have to PM you for added info so I might try my hand at replicating that.  Everything you're doing is stunning.  Count me as a fan too and will be waiting for YOUR future updates.  btw, doesn't matter how long it takes if you're willing to do what it takes to make something special like that...........you take all the time you need, we'll be here waiting.   cheers, tim

[Pete J.]

Man, THAT is slick. Small scale engine-turning? Too cool. It tries my patience to do that in 1:1.  

Bill, thanks for the comment.  I think doing two engines really tests the patients.  

 

Edited February 11, 2017 by Pete J.

[Pete J.]

Pete....Pete...........Pete.......(did I say Pete?)  finally, you've posted a build / WIP and I must say I'm NOT disappointed, that's fantastic and I love the subject you're tackling.  That turned engine finish is something I'll have to PM you for added info so I might try my hand at replicating that.  Everything you're doing is stunning.  Count me as a fan too and will be waiting for YOUR future updates.  btw, doesn't matter how long it takes if you're willing to do what it takes to make something special like that...........you take all the time you need, we'll be here waiting.   cheers, tim

Tim, thank you for your kind comments. As I mentioned at the start, it was your work and Randy's that got me off the couch to start with.  Thank you for the motivation.   I would be happy to share the engine turning process with you and anyone else that wants to try it.  It isn't that complex, just tedious.  More challenges to come.  Thanks for the support.  

[GT4494]

Are you building the 100P?

[Pete J.]

Are you building the 100P?

Yes indeed!  It is going to be quite the challenge.  Thank you of looking

[Dave Ambrose]

Pete,

Was there a particular reason for choosing 7075? 

[Pete J.]

Pete,

Was there a particular reason for choosing 7075? 

Dave actually there were several reasons but mostly it is just much better to machine than 6061.  It is harder so the chips clear tools and drill bits better.  It is less likely to gall to the tools and it polishes up much nicer.  The other reason is that it has a higher melting point.

 Now that doesn't sound all that important, but I am using superglue to temporarily secure parts to do some finish machining.  In this photo the cam covers have been glued to the block to skim each end to get a perfect match.  Then they were drilled for the wire pins that will be used for final assembly.  CA glue has a strong enough bond to hold for light to moderate machining.   To disassemble them, for the engine turning, all I had to do was heat them with a propane torch.  The super glue gives up quite nicely when heated and a quick soak in acetone cleans off any residue. 

 

 

Edited July 20, 2017 by Pete J.

[Codi]

Great tips Pete. I just learned a new trick, that being the heat to release the super glue.  I've used acetone to remove it but I'm going to be in need of this method for a particular reason.  THANKS!!  I was not as knowledgeable about the various grades of aluminum beyond the standard 6061, I've tried others and stumbled across the 7075 for the Donovan. I used it to make some pieces and everything you mention about it is true.  I bought more.     What scale are the engines Pete?   Lastly, I want to acknowledge the beautiful soldering job you did on the coolant pipe and the fact you heated and stretched the individual pieces to replicate the part.  That type of detail goes unnoticed all too often.  Now get back to work.  cheers

[GT4494]

I met the man who was instrumental in finding the plane.  He wanted it for the engines only.  This was 2011.

Here is the article he had about it at the Osh Kosh museum.

One of the "continuation cars they were building.  Original drive train and the rest built from original plans.  Cars he made were considered "Real Bugattis" and allowed to be shown in concourse events such as Pebble Beach They were also allowed to run as vintage cars at the Monterrey Races

[Pete J.]

Great tips Pete. I just learned a new trick, that being the heat to release the super glue.  I've used acetone to remove it but I'm going to be in need of this method for a particular reason.  THANKS!!  I was not as knowledgeable about the various grades of aluminum beyond the standard 6061, I've tried others and stumbled across the 7075 for the Donovan. I used it to make some pieces and everything you mention about it is true.  I bought more.     What scale are the engines Pete?   Lastly, I want to acknowledge the beautiful soldering job you did on the coolant pipe and the fact you heated and stretched the individual pieces to replicate the part.  That type of detail goes unnoticed all too often.  Now get back to work.  cheers

Tim, glad I could contribute to your knowledge base.  That is what I like about sharing with other builders.  You never know who is going to give you that one tip that you really need.  

The engines are 1:24 scale.  That is definitely and odd scale for an aircraft and would make this a very large model but it is really a tiny aircraft.  The wingspan in scale is about 14".  This is really one of those machines that if it didn't make it faster it was taken off.  Very minimalist.  This philosophy is likely what caused the accident that killed Scotty Wilson.  I have not read the FAA accident report yet but,  I have read several aerodynamic studies and it seems that there was minimal rudder authority. Any adverse yaw could put the air frame into flight regime from which it could not be recovered.  Not a slam against Scotty as he was a highly skilled pilot, but this was an aircraft that was designed to fly at the edge of the envelope and any time you do that, you increase the level of risk proportionatly. 

Thank you for your comment on the coolant pipe.  You are right, it is these sublties that go unnoticed and are the real challenge to get right. Thanks for noticing!

Now back to the bench.  Thanks Tim.

 

[Pete J.]

I met the man who was instrumental in finding the plane.  He wanted it for the engines only.  This was 2011.

Here is the article he had about it at the Osh Kosh museum.

One of the "continuation cars they were building.  Original drive train and the rest built from original plans.  Cars he made were considered "Real Bugattis" and allowed to be shown in concourse events such as Pebble Beach They were also allowed to run as vintage cars at the Monterrey Races

Norm, I have read the story about this and you had to be exceptionally lucky to meet this man.  Of course the aviation community is quite distressed about what happened to the original engines.  I do understand why he did it and don't blame him in the least.  After all, he was responsible for bringing the entire aircraft back to the US.  The 100P was never really well known until after he had converted the engines back to auto engines.  The problem is that these engines were, as well as can be determined, two of 7.  There is only one know to exist in its original format and that is a partial test engine which is incomplete.  It is driving me nuts because I am trying to figure out the plumbing on the originals.  The difference is that front and back engines were quite different.  The rear engine had the supercharger mounted on the left and the front was mounted on the right.  The rear engine was also fitted with a gear box to reverse the rotation out of the engine. This is just the basics.  I am having some real challenges with divining the ignition system.  It seems that there may have been a remote magneto where as the auto engines most often had a cam driven distributor system.   Very much a challenge to get this all figured out.   Like so many, I would like to pick his brain on what he did to convert the engines.  

Edited February 12, 2017 by Pete J.
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[Codi]

Okay Pete, I gotta call you and Randy out tonight......time for some updates right?   cheers, tim

[Pete J.]

Okay Pete, I gotta call you and Randy out tonight......time for some updates right?   cheers, tim

Not a problem Tim.  Seems I have been making a lot of scrap metal lately.  I am working on the valve cover clips and have made 40 or so and have  5 usable.  I need twenty. Will post when I have them done!  

[89AKurt]

I met the man who was instrumental in finding the plane.  He wanted it for the engines only.  This was 2011.

Here is the article he had about it at the Osh Kosh museum.

Oh man, I picked up a resin kit of that plane!
Awesome job with the engine turning.  I recently tried that with an electric erasure, using a gritty erasure, results sucked.

 

[Pete J.]

Ok, finally got the valve cover clips done!  All 20 of them.  Well I wound up with 26 because I know I will loose one or two of them. 

This is them with the bolt in place.  I still have to decide if that should be a nut or bolt.  They are made with a strip of .032" brass.  

 

Making this was a real chore!  I started by gluing the brass strip to a block of 7075 aluminum that I milled square and then drilled the holes. That is a .020 carbide drill bit. 

 

 

I soon discovered that super glue was not strong enough to hold for the milling.  So I pinned each hole with wire. 

 

 

 

This is after milling the fillet.  If you look carefully you can see some of the holes are off and some of the fillets are not quite right.  This is because of bit deflection(taking to deep of a cut) and sometimes just me screwing up the measuring.  I would loose count of how much I turned the hand wheel.  

 

 

 

After the bar was milled and separated from the aluminum block the clips needed to be cut to length.  This shows the cutting jig I made to guide my jewelers saw that I cut them to length.  The last process was to file the fillets at a taper.

 

 

This last photo is my education file.  This is all the scrap I made trying to figure out exactly how to do this.  Learning can be painful! 

 

 

Thanks for looking.

Edited July 20, 2017 by Pete J.

[Randy D]

You are a little bit crazy my friend  in a good way !!!  Superb tiny parts you have there Pete.  I vote for the nut with a bit of stud showing !

Randy

PS....  how many bits did you go thru?

[Pete J.]

You are a little bit crazy my friend  in a good way !!!  Superb tiny parts you have there Pete.  I vote for the nut with a bit of stud showing !

Randy

PS....  how many bits did you go thru?

Randy,  thanks for the comment.  I decided to do the nut and stud this evening.  That seems to be the way it is on the real aircraft, as near as I can tell from very fuzzy old B&W photos.  Your concurrence just cemented the deal!

The last photo shows all the scrap bits of brass that just didn't work.  That doesn't include the pieces that were hurled at the trash can in disgust!  I would guess I used about two and a half feet of brass strip to get 20+ pieces .160" long.  I was so frustrated early on, that I had to walk away and let the old brain consider other ways to make this part.  Sometimes it is the littlest stuff that drives you nuts!

Thanks again for your comment.

[Codi]

Stunning Pete.  I love how they turned out & as importantly, the time you took to post pics and the method you went about making them.  I truly appreciate what you did there & my hat is off to you sir!   cheers