The Bucket Foundry

[Cheesy]

Forget gyro's for now. What's wrong with this as a concept? Ball valve, uses a piston type ring to seal ( curved sealing surface ) ball sits on bearings, hollow, internally cooled, occilates so the ring gap never goes over the port also gives dwell at open and shut. I have shown this picture here before. This unit would be no good as it's just aluminium and would probably expand and seize perhaps. Tell me why it won't work with maybe a ceramic port liner?
Ring should work just like it would in a cylinder?
I am talking about using it as an exhaust valve in a twostroke head.

How well does it have to seal?
If it was something I was doing I would be concerned with the strength of the "thin" side of the ring land. I also think that the surface the ring runs on will wear very quickly near the pivots where the ring velocity is low. And finally Im not sure how well it will seal, half of the ring will be pushed onto (maybe) the wrong ring land to seal combusion presure , ideally the actual ring profile will be a bit starnge.

Would it be possible to have a seal in the head with a wave spring under it ? maybe a carbon seal on a really hard ball

[husaberg]

Interesting links
http://myfoundrycoach.com/blog/?page_id=115
kiwi v twin
https://www.behance.net/gallery/3382691/The-V-Twin

[Bert]

kiwi v twin
https://www.behance.net/gallery/3382691/The-V-Twin

Auckland uni and there SAE projects are really producing some cool stuff.
Quite interesting the concept around CF as an option for crank cases...

Good find Husa

[Grumph]

I can't open that link - normal for me - but it brought back to mind the pourable, castable,carbon fibre based bog that John Britten used for injector bodies. I had to machine up a couple of early ones using the original alloy ones as patterns. Weight was less than 1/3 the alloy ones... Machined quite well but left black shit everywhere. Took tapping well too although if you wanted a load bearing thread you'd be better off putting a decent metal insert in.

I was told at the time it was only a little less strong than untreated cast alloy.

Husa, can you use your powers for good (instead of finding porn...) and try and establish just what this stuff was please. There's no mention of it in the books on John.

Thanks

[husaberg]

I can't open that link - normal for me - but it brought back to mind the pourable, castable,carbon fibre based bog that John Britten used for injector bodies. I had to machine up a couple of early ones using the original alloy ones as patterns. Weight was less than 1/3 the alloy ones... Machined quite well but left black shit everywhere. Took tapping well too although if you wanted a load bearing thread you'd be better off putting a decent metal insert in.

I was told at the time it was only a little less strong than untreated cast alloy.

Husa, can you use your powers for good (instead of finding porn...) and try and establish just what this stuff was please. There's no mention of it in the books on John.

Thanks

Porn is good You old goat

An extension of the design of the engine was my Final Year Research Project titled Design, Analysis and Manufacture of a Carbon Fibre Composite Engine Crankcase.
Abstract:

This project investigates the use of Carbon Fibre Reinforced Plastic in an enginecrankcase for the University of Auckland Formula SAE Team. The engine forwhich this crankcase is being developed is a custom 500cc 4 stroke internalcombustion V-Twin engine. The use of CFRP can minimise the amount ofoutsourcing and cost required to manufacture their engines.
The three fundamental functions of this crankcase are to support the loadstransmitted through from the cylinder through the crankshaft to the gearboxduring engine operation and to contain oil.

The key issues that are unique to using CFRP to manufacture a crankcase are oilabsorption and high temperatures affecting the mechanical properties of thecomposite and the manufacturing of the component by a Formula SAE teammember with a limited skill set.

Tensile and short beam shear tests were conducted to show that the MTM28Carbon Fibre Prepreg that is available to the team is suitable for manufacturingthis component. A pullout test was conducted to show that CFRP with helicoilinserts can retain the thread of a highly loaded headbolt. Thermal expansionanalyses were conducted using Abaqus FEA software. The analysis shows thatCFRP can be used to manufacture bearing housings.

The proposed design concept simplifies the manufacturing process so that themajority of the component and its moulds can be manufactured in house by theaverage Formula SAE team member.

This is the prototype top half of the carbon fibre crankcase. This was manufactured in less time and for a lower cost than a CNC machined billet piece.
This project won an award from the Composites Association of New Zealand.

One thing not many people appreciate is carbon fibre plus alloy inserts equual electrolysis it needs to be anodised or be stainless or coated etc.
a purable product my money is own it being a DuPont product
in the Lionheart articles I have posted Ian Cramp mentions such a product but says it has to be diecast.
MCM ran a article on a plastic engine that had plastic cases etc even a plastic piston it was ceramic coated that was in about 1984...
You will have it in your mag collection, the cover was mainly yellow and I think it had a Norton ES2 on the cover of it as well.



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[ken seeber]

Neil's spherical exh valve.

There have been lots of attempts and I think the most successful being the Bishop system:

http://www.google.com.au/url?sa=t&rc...80185997,d.dGY

I have attached a rough sketch of my understanding of the proposal. Without trying to be a negative prick, to me there are issues:

1. Assuming it is spinning at half engine speed, the rate of exh opening might not favour the creation of a strong exhaust pulse
2. The piston would have more surface area, leading to excessive heat input
3. The scavenging of the piston bowl may be difficult

Materials. I believe the Bishop used some form of stainless valve, with the seal grid elements being stationary, presumably using a spark erosion process to manufacture the grooves within the "shadowed" valve bore in the head..

For me, I think the reverse is the way to go in some ways. http://www.pit-lane.biz/t5121p260-gp...vermars-part-4. Approx half way down.

In the end, all these things will only succeed with the drive of the inventor and his/her ability to overcome all the obstacles, despite comments from outsiders such as myself. However I reckon, if anyone can make a go of it, it is Neil. So best of luck and again, I just love your evolving of patterns, the castings and the machining.

Ken

[WilDun]

Just got back and have checked out all the developments of the last 24hrs on this thread - of course Husa has found some stuff, Grumph has contributed some interesting stuff in machining carbon fibre for Britten.

Ken, interesting stuff on the Bishop Valve, which, unless I'm much mistaken was taken from a much older and almost identical design, which I'll find after I rummage through my "archives".

Don't really want to get totally away from the original thread, but I'm going to try and post some pics of an interesting engine design of the late sixties also from my archives, (read grotty old scrapbook), this design apparently uses the same sealing method as you are proposing Neil. - of course the whole design is not a two stroke (or is it?).
I feel that the surface speeds at the sealing surfaces may be have been too high though, then again maybe not.
Obviously the design wasn't finalised and up and running, possibly not reaching the prototype stage.
Having had a quick look again, I can see that I hadn't sat down all those years ago and thought about the concept thoroughly enough to properly understand it !

[Flettner]

Ok then, what other systems for a valve in the head? NOT popet valves!

[Grumph]

Ok then, what other systems for a valve in the head? NOT popet valves!

Given what's now known about chamber shape and squish velocity - and that the squish needs to be symmetrical...I'm not sure there is a solution to putting an exhaust valve in the head.
I thought the sleeve valve was going to give you the right chamber shape plus rapid ex port opening ?

[Flettner]

Given what's now known about chamber shape and squish velocity - and that the squish needs to be symmetrical...I'm not sure there is a solution to putting an exhaust valve in the head.
I thought the sleeve valve was going to give you the right chamber shape plus rapid ex port opening ?

Yes, but I'm trying to think up other ideas to test as well.

[husaberg]

Ok then, what other systems for a valve in the head? NOT popet valves!

Remember the NZ dude had the funny engine he used to run on a vacum it was named after him why not build that?
I have scans with the plans of it pretty sure i do.
Pretty sure he never finished it it looked pretty cool actually.
it was a contra rotating true rotary if memory serves me, with two chambers at right angles.
it was don yeltman or something like that anyone?

[WilDun]

Ok then, what other systems for a valve in the head? NOT popet valves!

I believe that Piaggio (scooters) were experimenting with and may even have been producing a small piston/cylinder arrangement up top c/w exhaust ports only. which opened normally at BTD, ( much like your uniflow only with a much smaller cylinder & piston up top).
In one configuration this small cylinder was running at right angles to the main cylinder, supposedly to make it shorter.
Guess it was quite short stroke and probablythe exhaust ports were right round the bore.
Seems it worked well - might be able to find pics of it somewhere, I did find them a couple of years ago but they seem to have disappeared.

Another guy was experimenting with a small wankel rotor arrangement which he somehow got to work as an exhaust valve! - It may have been designed to run at one third crank speed too. However, I don't have any details, as it was quite a few years ago.

[WilDun]

I found the article on the scooter engine (it was Piaggio but actually called a VESPA ET2 circa 1997) - located it tucked away in a ring binder.
However, I'm afraid I got it a little bit wrong, - it seems that the small piston up top was actually used as a stratified charge pump which draws in a very rich fuel mixture and compresses it then squirts it into the cylinder, maybe similar to the Aussie 'Orbital' injector system, I dunno. The rest of the engine is a normal two stroke except that the scavenging air has no fuel in it when it comes from the transfers until it mixes with the rich pressurised mixture from above, ie when the ports have closed.

Sorry about that! - The subject is starting to wander from the original I know, but if you're still interested I'll scan the article and drawings and post them here..

[husaberg]

yeoman (dave) was the inventor I have found the drawings but can find nothing on the web
its a twin rotor design no cranks no pistons.

He was 82 in 1987 so I guess he is no longer with us.
It looks like it was never finished.
it would need some pretty tricky casting and machining

The two Rotors are at 90 degrees from each other and as soon as I can figure out how to use the scanner I will post it.

[Grumph]

yeoman (dave) was the inventor I have found the drawings but can find nothing on the web
its a twin rotor design no cranks no pistons.

He was 82 in 1987 so I guess he is no longer with us.
It looks like it was never finished.
it would need some pretty tricky casting and machining

The two Rotors are at 90 degrees from each other and as soon as I can figure out how to use the scanner I will post it.

Yeah, Dave's dead but his son is still around ChCh somewhere. I seem to remember him coming to see the old man with drawings back when i was living at home. The old B often got asked for opinions on oddball shit - AMIMechE and a long race history and the family habit of offering opinions on anything got us a lot of visitors...
Dave was a Scott fanatic so I'd expect anything he did to be odd....