Squint Scale Curtiss Model K Aero I4

[RReid]

Having done a previous project based on an early Glenn Curtiss engine design (my 2-Bits v-twin), I thought I would return to that well once again. In researching that engine and others since, I have found it interesting to “follow” the development of those early engines.

Starting from singles and v-twins (and one V8) meant for motorcycles, air-cooled and with and intake-over-exhaust layout and atmospheric intake valves, they evolved to inline fours and V8s, still with air-cooling and the same valve train, but meant for dirigibles and winged aircraft. All of these share very similar, if not identical, cylinders, cylinder heads, and cooling fin and valve layout.



As the development of flying machines progressed, the air-cooling and atmospheric intake valves had to give way to water cooling and overhead valves in order to get the power and reliability needed. So the cooling fins gave way to water jackets and a new valve train was developed that used a push-pull rod to activate both the intake and exhaust valves via a single rocker.


I think the final iteration of this design development is the Model O, especially the famous OX-5 V8 of the WWI era, with its concentric push-rod/pull-tube layout and unique rocker design.


I had initially thought to build a version of the air-cooled I4, and got pretty far along in developing a CAD model of that. Part of the appeal was this cool photo of Glenn Curtiss holding one, with it's cooling fan in place.


But then I got intrigued by the push-pull valve train of the water-cooled models, and the challenge of figuring out how that worked. So that's what I'm gonna build.


Work has commenced with the upper half of the crankcase, which I'm piecing together from 1/4” x 1” brass bar stock. Two pieces silver soldered together were needed to get the required width for the top plate. The end plates are attached with brass 1-72 screws and silver solder. Side plates will probably just be soft soldered.

[Dave Otto]

Cool research and another fun project to follow along with. 

Dave

[crueby]

Very neat engine!   




And for anyone in or passing through that part of the world, the Glenn Curtiss museum by Hammondsport/Watkins Glen in south central New York  state is well worth the visit. All sorts of airplane, motorcycle,  boat stuff there.

[cnr6400]

 

[Kim]

Looks like a fun project, Ron!  I'll be following along 

Kim

[Admiral_dk]

OK - so you are ramping up the Ambitions 

Very interesting project, that I will follow with delight 

Per             

[vtsteam]

Really nice! 

[simplyloco]

I will follow with great interest.
John

[RReid]

Wow, Thanks guys! I really do appreciate your interest and encouragement.

And for anyone in or passing through that part of the world, the Glenn Curtiss museum by Hammondsport/Watkins Glen in south central New York  state is well worth the visit.

When my son worked for a sports car racing team and I lived in MD, I drove up to Watkins Glen several times to help as an extra crew guy. If I'd only known then what I know now, I would definitely have made time to get to that museum. It's kind of a long hike now.

[ddmckee54]

"Squint Scale", is that anything like "Stand Way Off Scale"?

[RReid]

"Squint Scale", is that anything like "Stand Way Off Scale"?

Yeah, something like that.

[RReid]

Not a lot of progress since the introductory post, but I have gotten the upper crankcase fully “boxed. The small holes on top are for the pushrods, the big ones still need to be bored out to final size to take the cylinders. Boring for the crank bearings can't be done until there is a lower crankcase, or at least a lower bearing housing (an idea under consideration), and boring for the cam bearings doesn't need to be done yet and will be put off until I'm sure the camshaft design is finalized.

Milling the little angle of the side plate in situ so that it exactly matches that of the end plates.


I find that shiny parts can sometimes be hard to photograph without weird reflections or bright spots. Finally found a location that worked.

[steamer]

Nice project Ron!    Watching along!!!

Dave

[Admiral_dk]

Looks like you are off to a good start Ron 

A build-up Crankcase, by the looks of it - are you going to solder the supports for the Crank and Camshaft in later ?

Per         

[Dave Otto]

Very nice Ron!

Dave