VW Heads Designed for Aircraft- Poll

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Value of purpose built VW aircraft heads

  • Why bother. Who would try to use '30's auto technology to fly.

    Votes: 1 4.2%
  • It's an interesting idea but what we have now is good enough.

    Votes: 2 8.3%
  • If they were close in cost AND better I'd probably use them

    Votes: 11 45.8%
  • It's been needed for a long time. They will make the VW a far better option.

    Votes: 10 41.7%
  • It would be the best thing to happen to EABs in the last 2 decades

    Votes: 0 0.0%
  • Why bother. Who would try to use '30's auto technology to fly.

    Votes: 1 4.2%
  • It's an interesting idea but what we have now is good enough.

    Votes: 2 8.3%
  • If they were close in cost AND better I'd probably use them

    Votes: 11 45.8%
  • It's been needed for a long time. They will make the VW a far better option.

    Votes: 10 41.7%
  • It would be the best thing to happen to EABs in the last 2 decades

    Votes: 0 0.0%

  • Total voters
    24
  • Poll closed .

Aviacs

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This might be a simpler way to verify the concept?

Is that a new casting with relocated ports?
Or is it a lot of plugs, add-on material, and welding?
It would be interesting to see how things were located around the pushrod tubes and rocker geometry.

That is more interesting than the water jacket.

NB: There is a 2276 VW on the nose of my Sonerai 2 project, but i am not actually conversant with VW engine architecture. I was more into Brit sports cars & motorcycles (wrenching & machining), and then ended up in pick-up trucks as my career veered into millwork and construction early on.

smt
 
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I only see 2 cores so far, depending how the finning works << >>

Is that a new casting with relocated ports?

Getting off topic:
I was thinking water cooled head with that post - no fins. One core for each port and the water jacket core being 2 separate parts. Valve guides cast solid.
<< >>
Best pic I could find quickly. Both are aftermarket racing head castings. The inner fins are milled down and a strap of aluminum welded to the top and bottom fins. Typically with this mod there is need to seal of the head bolt passages, at least with stock heads.
 

Aviacs

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Messages
439
I was thinking water cooled head with that post - no fins. One core for each port and the water jacket core being 2 separate parts. Valve guides cast solid.

So that lower skull cap -is- the head (sans rocker boxes); not just an outline of the combustion chamber?
I'm probably being obtuse, but would need to see some dotted lines and the the water ports. Or maybe just a 3D of all the negative spaces?
You probably know more about how to flow molten aluminum without bubbles and to minimize shrinkage and cooling distortion. Sometimes, if a "blob" in the uniform section rule is not too much of a pucker, solid is better. If, OTOH your conception is based on "difficulty", guide cores can be part of the rest of the tract. (blown integral with the port core). In some cases they can even provide support to the core to keep it from rotating as it tries to float.

On subject of demonstrating my obtuseness, i had incorrectly perceived the water-cooled head photo. Was mistaking the water ports for re-located intake or exhaust ports, but couldn't make head nor tail of how they ran into the combustion chamber. As might have been obvious from my response. I"assumed" the normal ex ports were blanked off & completely failed to realize immediately that of course water ports would be a factor. Anyway, as my son was fond of reminding me: dawn breaks on marble head".

smt
 
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Was mistaking the water ports for re-located intake
Easy to do. It is a very misleading photo and I was just too lazy to do any editing. :oops:

There is no water jacket in my CAD render, just the combustion chamber 'skull cap', ports and valve guide bosses. Imagine a hollow cylindrical upside down can above the skull cap with the ports and valve guides sticking out.
 

Rik-

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Sep 13, 2019
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I am not a professional pattern maker, though i have made professional patterns and core boxes. :) (Pro= they made commercial products cast in multiples that sold reasonably well. In one case, they would still be selling except my last foundry went out of business and the patterns were stolen or destroyed. The parts were large and the margins low, i have not been inspired to make new patterns, and the "competition" has caught up selling similar models.

Starting with that "qualification" I only see 2 cores so far, depending how the finning works out to orient the combustion chamber in relation to the parting line. I "imagine" there will be another, or couple more, cores for the pushrod channel once that is worked in, so if you were including that; then "yes". OTOH I'm assuming shell cores, not paste-up. Modern foundries don't want to work with paste-up cores, and the cost per casting is an impressive factor higher cost. Shell cores will also give very smooth dimensionally uniform, essentially "lost wax" surfaces, say, in the induction and exhaust ports.

Looking harder at your drawing, i'd almost go out on a limb and suggest one shell core could do the whole negative space.
They do shrink and can slightly tear coming out of the shell core box, so overall dimensions and locational tolerance could be a factor. As would, again, the finning and parting line(s) to determine available geometry to position the core prints in the pattern. (IOW, it could be possible to blow the entire core as a unit in 3D space. However, if the points where "the ends" must fit to the 3d space of the primary pattern don't admit (nearly) parallel entry, then one or the other might have to have to be broken down into smaller interlocking components).

I don't assume i'm telling you anything new, but there may be others following along. :)

smt

3D print the cores, it saves a ton of $ on short production runs.
 

dave wolfe

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Messages
189
Two or three groves and no washers. The valve springs sit on the heads.

Ive got no first hand experience, but the three groove style is designed to allow rotation between the valve and the keeper. Id take a look to see if u can twist the keeper and retainer independetly from the valves.

With the single groove valves ala CB, the keeper / retainer / valve are all stuck together not being able to twist independantly so I guess the idea is to make sure to use shims under the calve springs to encourage the springs to twist? Not sure if it works or not.
 

jeffwalin

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sotaro

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I always thought the Great Plains water cooled heads were modified VW Wasserboxer heads…

I don't think so. The heads are quite different. I believe the water cooled heads came from or went to Brazil. I was able to find online evidence of them there about 5 years ago. They were no longer for sale there at that time.
 

Aviacs

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Oct 21, 2019
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439
Reasonably convicted an ISX style head would outperform most typical installations...

You're really gonna have to explain that one.

We should use cast iron heads?
greater than 15:1 compression ratio?
How does that style head better accommodate the ex, int, and pushrod routing for a VW?

What exactly is applicable?

Thanks!
smt
 

Aviacs

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Messages
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3D print the cores, it saves a ton of $ on short production runs

That's interesting not least because (I assume?) they could be printed hollow (like blown shell cores) once suitable crush vs strength was determined. So are you saying that there are 3D machines that can be loaded with resinbond sand or other pyro material and print a core en bloc? How long does it take for a part the size of a VW intake tract, if the surface finish is comparable to blown shell cores?

smt
 

Vigilant1

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General question: From a molding/fabrication standpoint, the cast fins on these VW heads seem to be a major challenge. They were easy/cheap for VW because they made hundreds of thousands per year. Would it cheaper or even have advantages for aircraft use to do things very differently? Random ideas based on my near-zero knowledge of foundry, molding, 3D printing:
1) No fins, go to fluid channels or even large-ish gallery spaces and move the heat away to a heat exchanger using oil (preferably) as the working fluid. This would even out temps across the head and allow a designer to put the heat exchanger wherever was best. Cons: need a high volume oil pump, the engine installation isn't a drop-in replacement for other Type 1s (now needs different cooling air flow).
2) Make heads with large flat areas to accommodate bolt-on banks of extruded metal fins (sorry, I've mentioned this before). These "heat sink" (heat exchanger) fins are available OTS and could be scaled to the requirement.
3) Mold the cylinder head as a large monolithic piece, then use ganged cutters to remove material, leaving fins of desired thickness and depth.
 

WonderousMountain

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We should use cast iron heads?
greater than 15:1 compression ratio?
How does that style head better accommodate the ex, int, and pushrod routing for a VW?

What exactly is applicable?

You're right, that takes some explaining.

Cast Iron heads would not be advisable, although they're still in use on some smaller motors. Presumably because of the high pressures involved with diesels & Compress charge engines.

Higher compression would be a boon, not 15/1 but chambers of 33cc would be plenty good.

What I meant was Flat Deck - Bowl in Piston would accommodate Cylinder head design for a home builder, the size of the combustion chamber is no longer fixed by the head, angle is set as to push rods, they aren't really my style, yet, we'd be better off with three or more tappets. Although, it may be engineering excess at direct drive maneuvering speed RPS.
OIP (4).jpeg
The 409 had a flat deck design, but chose instead a dome piston to cause a wedge chamber to form. Different domes yielded target CR and it reached one HP/In'3 street legal.
 
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Aviacs

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Messages
439
General question: From a molding/fabrication standpoint, the cast fins on these VW heads seem to be a major challenge.

? meaning?
(I don'ty see it as a pouring or cost issue, but possibly being a bit blase or even faintly naive?)

They were easy/cheap for VW because they made hundreds of thousands per year.

No doubt.
Any production foundry would prefer to quote on steady high quantities of a job that repeats year after year.
That is a large commitment by both parties, though.

Would it cheaper or even have advantages for aircraft use to do things very differently? Random ideas based on my near-zero knowledge of foundry, molding, 3D printing:

You have to be able to cost estimate both ways to make a determination.
That is after the engineering to determine feasibility for solving a specified problem or problems.

The biggest cost factors are in resolving unknowns. Essentially in this order:
1.) design the darn thing. Near as possible to be foolproof given a weight & perhaps cost limit. Build on prior art and experience.
2.) Analyze and adjust the design to minimize machining operations, and enhance the ease and speed of those required.
3.)Build the foundry tooling.

1 is where most projects never get adequately started.
3 is where many viable designs are left on the drawing board.

smt
 

Vigilant1

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General question: From a molding/fabrication standpoint, the cast fins on these VW heads seem to be a major challenge.

? meaning?
(I don'ty see it as a pouring or cost issue, but possibly being a bit blase or even faintly naive?)

I dunno, but when, as a consumer, I get the things from the manufacturer the through chanels are often occluded with flash. And, for whatever reason, the "fineness" of the fins on these cast heads appears to be limited (e.g instead of 8 fins, could they cast 10 fins in the same distance?). Now, they need to be thick enough to survive and to carry heat their full length, and sufficient air must move through the slot between them. But, given that, more fins per inch = more surface area for heat exchange = cooler heads. Can we get better fins if we extrude or cut them? Cost?
 
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