scratch building a pair of 1:24 scale Bugatti engines

[Deleted]

This is my first thread on this web site.  Hopefully it will be of interest.  This is a long term project that I have been working on for a while.  It is a pair of scratch built Type 50 aero engines.  I am basing the engines on some photos and a Fischer Patterns resin kit.    It is my intention to make them from 7075 aluminum.  I will be posting progress over time so it may be weeks or months between posts.  
 
These are the basic engine blocks.



The next step was to cut and set up the mounts for the two valve covers.  





I then had to figure out how to engine turn the head and valve covers.  This is an extremely tedious process.  I super glued .010" wire inside a piece of .100" steel tube to make each of the brushed circles.

 



I then made a jig to help align german silver wire to solder up the coolant pipe for the head of the engine.  The lower part is the resin piece.  I think you can see why I replicated it in metal.  To my eye it looks much better.  



This is the work so far.  The valve covers are temporarily held in place with locating wires.  There is much more work to do on them and they need to come off to do that.  This is more of a test fit.  For those with sharp eyes you can see the resin pieces in the background.  


Thanks for looking.

[Art Laski]

Hey Pete! Glad to have you here. Knowing you, I'm sure this will be amazing.

-Art

[indy]

Quite the undertaking but it will be really enlightening to see how much work goes into what should be a stunning finished product.

Jordan

[clm1545]

Impressive work, to say the least. It sure looks a lot like an Offy.

[kip]

Wow. The engine turn finish is fantastic. Can't wait to see more.

kip

[Deleted]

Feb 10, 2017 16:42:11 GMT -5 clm1545 said:

Impressive work, to say the least. It sure looks a lot like an Offy.

Yes it does, except this is an 8 cylinder.  It does have a roots style supercharger, driven in the same way as an Offy.  

[1961redlegs]

You've my attention, impressive!

[johnwebster]

Are you building the Bugatti speed record airplane?

Leon Duray took two Miller straight eight Indy cars to Italy around 1930 to compete in the Grand Prix at Monza. The cars were impressively fast but failed to finish. Bugatti aquired the cars and his subsequent engines share some Miller design features. When the Bugatti factory was sold off in 1955 Grif Borgeson was there, recognized the two cars and managed to bring them back to the States. The black #4 Front Drive Miller in the Speedway Museum is one of them.

The Offenhauser is a direct descendant of the Miller straight eight so the resemblance is more than coincidence.

[racerbrown]

this is going to be a real treat!
duane

[Deleted]

Feb 10, 2017 16:08:16 GMT -5 Art Laski said:

Hey Pete! Glad to have you here. Knowing you, I'm sure this will be amazing.

-Art

Art, thanks for your kind words.  I have been lurking here for a while but felt this build might be of interest to some open wheel types as the basic engines ran at Bugatti gran prix cars.  Thanks again.

[Deleted]

Feb 10, 2017 21:08:18 GMT -5 johnwebster said:

Are you building the Bugatti speed record airplane?

Leon Duray took two Miller straight eight Indy cars to Italy around 1930 to compete in the Grand Prix at Monza. The cars were impressively fast but failed to finish. Bugatti aquired the cars and his subsequent engines share some Miller design features. When the Bugatti factory was sold off in 1955 Grif Borgeson was there, recognized the two cars and managed to bring them back to the States. The black #4 Front Drive Miller in the Speedway Museum is one of them.

The Offenhauser is a direct descendant of the Miller straight eight so the resemblance is more than coincidence.

Yes, they will be going in a 100P. I have the 1:24 scale Fisher Pattern model.  Although Paul did a great job with the engines, I just felt this deserved a better effort on my part.  

You are right about the Miller cars.  Like all builders or the era, Bugatti was not afraid to adapt other successful elements into his design.  However, these engines are unique in how they were adapted for aircraft use.  This was cutting edge technology for the time and although both engines look similar there were major differences between the left(forward) and right(rear) engine.  That is one of the major challenges of this build is to make two acceptible engines, each with unique parts.

[Gary Davis]

This build is looking very good Pete. The engine turning you did is flat AWESOME.

[Deleted]

Feb 10, 2017 16:10:43 GMT -5 indy said:

Quite the undertaking but it will be really enlightening to see how much work goes into what should be a stunning finished product.

Jordan

Thanks, Jordan.  It is going to be a long haul for this one.  Even if I can get a couple of hours a day at the bench, I expect it to take at least a year.  Thanks for the kind words. 

[Deleted]

Feb 10, 2017 17:26:11 GMT -5 kip said:

Wow. The engine turn finish is fantastic. Can't wait to see more.

kip

Kip, it is one of the most tedious things I have had to do in a while, and I still have the valve covers to do on the #2 engine.  There is a fair amount of engine turning on the model including a the flat surfaces in the cockpit.  Thanks for looking. 

[Deleted]

Feb 10, 2017 17:57:31 GMT -5 1961redlegs said:

You've my attention, impressive!

Thank you.  I hope the work lives up the quality I have seen on the forum.

[Deleted]

Feb 11, 2017 0:20:26 GMT -5 racerbrown said:

this is going to be a real treat!
duane

I am hoping that I can keep the interest going.  It is easy to start something but not so easy to keep it going at times. Thanks for looking in.

[Deleted]

Feb 11, 2017 12:41:08 GMT -5 Gary Davis said:

This build is looking very good Pete. The engine turning you did is flat AWESOME.

Thanks for the comment.  Half way through engine turning on these two blocks and the motivation to keep it going is sometimes in short supply.  Thanks for the comment.

[johnwebster]

For those unaware of the prototype of the model Pete is working on here is a short history with some pictures:

www.eaa.org/en/eaa-museum/museum-collection/aircraft-collection-folder/1938-bugatti-model-100-racer

The original airplane is on display at the EAA Museum in Oshkosh, Wisconsin.

Pete, the engine turning looks great, could you show a closeup of the tool you made to do it?

[clm1545]

Someone built a replica of that airplane a year, or two ago. There was a website showing the whole process. Sadly, the second flight ended in tragedy.

[Deleted]

Feb 12, 2017 17:19:27 GMT -5 clm1545 said:

Someone built a replica of that airplane a year, or two ago. There was a website showing the whole process. Sadly, the second flight ended in tragedy.

Not picking nits but is was the third flight which was to be it's last before it was retired to sit beside the original at Oshkosh. There are videos of it's first two flights on Youtube.  

I was lucky to have had a series of email contacts with Scotty Wilson as he was building it.  He was most generous with information and actually sent me some original blue prints from Bugatti of the tail section when I had questions about the tail skid.  He also sent me the formula for the blue paint he used.  It was derived from the only painted original piece they had, adjusted for age, so when I paint this it will be correct.  It was not a true Bugatti blue but more of a violet hue.  

He and I graduated from USAF UPT at the same time, though I did not know him then.  I was heartbroken when he passed.  

[Deleted]

Feb 12, 2017 3:48:05 GMT -5 johnwebster said:

For those unaware of the prototype of the model Pete is working on here is a short history with some pictures:

www.eaa.org/en/eaa-museum/museum-collection/aircraft-collection-folder/1938-bugatti-model-100-racer

The original airplane is on display at the EAA Museum in Oshkosh, Wisconsin.

Pete, the engine turning looks great, could you show a closeup of the tool you made to do it?

I would be happy to do this.  I have had several questions about the process and was thinking of doing a video for Youtube.  If I get that done, I will post a link.  It is a simple tool but you really need a mill to use it.  

[Deleted]

Ok, I have been at it for a while learning how to make one tiny piece.  Before I go further with that I want to answer a prior request of a photo of the tool I created to do the engine turning.  I took a piece of 1/8" brass tubing and pulled a bunch of .010 stainless wire through it.  Once I got enough in so it was hard to pull, I put some super glue in and let that wick up the tube.  I then ground the end off on my bench grinder and fit it in my mill.  Here is what it looks like.




Now, what have I been working on for a month?  Well, I am a little embarrassed to say I have made 20 valve cover clips.  This are the parts that on the real engine hold the valve covers in place.  As I say a little embarrassed because it took me so long.  Here are two of the clips completed. 



This is the process.  First I glued a strip of .036 brass strip to a block of aluminum that I had milled square and drilled the holes in the brass. 




I quickly discovered that the super glue was just not strong enough against the shear force of milling even taking just .005" per pass so I pinned the brass to the aluminum, using wire in each of the holes.  



I then milled the grooves into each side of the brass with two passes per side.  Those with sharp eyes will see that there are issues with several of the clips with holes not centered or incomplete milling.  Some of that is flex in 1/16" end mill and others is just me not keeping track of numbers, but it all ends up with some scrap.  




Of course the next process is to cut the clips to length.  You can see the jig I created to guide my jewelers saw to the right length. 




I then filed the fillets with a needle file to taper them.  This last photo shows the cost of education these days.  This is all the scrap I created learning what worked and what didn't.  All of this to make twenty clips.  Actually I have 26.  I figure I will loose some at some point.




Thanks for looking.

[Gary Davis]

You're doing mighty fine work here Pete. I don't think I'd be embarrassed about the time thing at all. It takes what it takes. Thank you for sharing your engine turning tool with us too. Great idea..

[racerbrown]

i love watching you problem solving these pieces.
duane

[Deleted]

Mar 30, 2017 20:20:14 GMT -5 racerbrown said:

i love watching you problem solving these pieces.
duane

Duane, thanks for the comment.  I am not sure you would have wanted to share space with me when I was working this one out.    More than once I shut it down and walked away to let the old brain work out a different way of doing this.  I was lucky I had a good supply of brass strip. I guess I am thankful that I don't get frustrated easily. 

[Art Laski]

Wow, Pete!

[Patrick]

I quit!

Patrick

[Deleted]

Mar 31, 2017 10:21:35 GMT -5 Art Laski said:

Wow, Pete!

Thanks Art.  After seeing your midget racer I just had to get back to the bench.  It is guys like you that inspire me to do more.

[Deleted]

Mar 31, 2017 12:02:52 GMT -5 Patrick said:

I quit!

Patrick

Patrick, thanks for the good words.  I hope this is an inspirational thread and not a stop sign.  I am always interested in sharing tips and techniques with all.  

[alterrenner]

Just as impressive as the machine turning is the tool you built to do it!
I also like the idea of using aluminum--realism right down to the material!
--Frank