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810 Briggs Rabbit Hole - New Head Branch

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Hot Wings

Grumpy Cynic
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How were you thinking to cast these? Lost PLA in dry or greensand or ?
Greensand handles the heat pretty well but tends to flake off in the combustion chamber - scoring the cylinder walls. 😄

This is a trade I haven't really given a lot of thought. I really like lost wax but unless it is needed due to complexity using sand (K-bond) with CO2 set cores for the ports would be the quickest. The stock heads look to be done with a 6 part mold (top,bottom + 4 sides) This is easy enough to duplicate in sand but the 45 degree port flanges and curved ports kind of messes up that option. A built up multi-piece lost wax might be needed.

Thinking about using 3D printing for the patern to build the silicone wax molds.

Figuring out the best cooling air flow direction needs to be locked down first. This seems to be the most efficient. Would work better on an upright with up-flow cooling. But the reason for using the 810, for me, is to invert the engine.
colling flow.JPG
 

karmarepair

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Greensand handles the heat pretty well but tends to flake off in the combustion chamber - scoring the cylinder walls. 😄

This is a trade I haven't really given a lot of thought. I really like lost wax but unless it is needed due to complexity using sand (K-bond) with CO2 set cores for the ports would be the quickest. The stock heads look to be done with a 6 part mold (top,bottom + 4 sides) This is easy enough to duplicate in sand but the 45 degree port flanges and curved ports kind of messes up that option. A built up multi-piece lost wax might be needed.

Thinking about using 3D printing for the pattern to build the silicone wax molds.
This is not a trade I've exercised either, but I've read a lot....

What I was thinking: Cast in aluminum (old pistons, heads, and wheels) using lost PLA with a 3D printed "pattern", with the feeders and risers in the print, but form sodium silicate/CO2 set cores in the intakes and maybe between the fins. Ram up the results in a green sand (or Petrobond, or homemade substitute) flask. Feeding the fins will be the trick, but this way you can relatively rapidly try different feed/riser ideas.

EDIT: WRONG - Lost PLA is a form of investment casting. Lost FOAM might work that way, but trying to produce this part in foam, well, I suppose you could do it with a computerized mill, using relatively dense foam. I still think you maybe could do this in sand with a 3-D printed PLA pattern or five.

Myfordboy on YouTube is an amateur master; VOG (VegiOilGuy) has done some nice work too in this area.
 
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Hot Wings

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Feeding the fins will be the trick,
Feeding always seems to be the variable hardest to get right the first time. Alloy for this project is a whole project of it's own.

Watched one video of a guy doing lost PLA (probably Myfordboy). For a one of a kind project it is probably a very good option. For more than a couple it is just to slow to print.
 

TiPi

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Why not design the head for a weld-on port? Make the casting so that a suitably shaped alu pipe bend (1/2 of 90deg mandrel bend) will connect to the valve seat area at a slight angle and fit under the valve guide boss? Exhaust might be a bit of a challenge, SS is more suitable than an alu pipe.
Having the pipe angled slightly so that the incoming air is favouring the outside of the bend into the valve opening and up towards the centre of the bore should yield a better flow as well. It is usually beneficial to have a slight twist (off-set of the port direction) to induce some swirling of the incoming charge.
1596614496378.png
This how I would change the intake port (blue is OEM) without increasing the port diameter.
1596615084507.png
 

Hot Wings

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Why not design the head for a weld-on port? <> >> Exhaust might be a bit of a challenge, SS is more suitable than an alu pipe.
<< >>
Having the pipe angled slightly so that the incoming air is favouring the outside of the bend into the valve opening and up towards the centre of the bore should yield a better flow as well. It is usually beneficial to have a slight twist (off-set of the port direction) to induce some swirling of the incoming charge.
Interesting idea - will think about it.
<< >>
A cast in steel liner for the exhaust is something I've always considered a good idea. But that is getting away from the inexpensive part of the industrial engine idea. A purpose cast head is already getting off that path.
<< >>
This twist happens automatically when the intake port is moved 90 degrees. It needs to be offset slightly to clear one of the head bolts. I plan to leave enough wall thickness on the port so that if the actual shape needs any modification after testing that only a new port core needs to be made. One of the nice things about CAD is that the port shape can be pretty easily crafted anyway we want.
 

pictsidhe

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Way back when I was playing with air cooled 2 stroke bikes, I'd make the exhausts protrude as far inside the port as possible. This really helped with cylinder temps as I effectively insulated over half of the original port. If the head was designed for such a pipe, cooling requirement can be reduced. I would reshape part of the port to take the pipe.
 

Hot Wings

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Realized to day that I put the heads on the wrong sides. On the vertical engine the exhaust is on the PTO side, not the flywheel side. 😞

Corrected with a moved intake port:

Left on right.JPG Some fins.JPG
 

simflyer

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This is a table comparing some of the industrial engines that have been used or proposed for aircraft use over the last 10 or so years.

If you compare this data to "proper" aircraft direct-drive engines, the achievable power is around 40hp/lt and maybe 43hp/lt with everything optimised. The power/displacement is normalised to 3,600rpm and based on max power (not all manufacturers have max cont power advertised).
View attachment 100003

Aiming for 43hp/lt (35hp out of the Briggs 49) is already at the high-end. A set of new heads optimised for flow at the lower rpm might improve the output but I'm not sure by how much and if it is worth the effort. It would be very nice to try.
TiPi, did You finally found, how to rework 49M for use it as SE33? I'll test it with PSRU. Now testing VW 1930cc stroker.
 

TiPi

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Realized to day that I put the heads on the wrong sides. On the vertical engine the exhaust is on the PTO side, not the flywheel side.
Put the EX port to the out side and and the IN port towards the V and make it universal (heads up or down, pusher or tractor, flywheel or PTO drive).
 

TiPi

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TiPi, did You finally found, how to rework 49M for use it as SE33? I'll test it with PSRU. Now testing VW 1930cc stroker.
Project on hold for a few months, moving house. Nearly ready for assembly of converted engine.
 

trimtab

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recall the helpful advice in a Jaguar repair manual: "Remember that if factory replacement valve shims for the 3.8 liter engine cannot be found, the shims for a Lotus Cortina are also suitable.” Great! Pep Boys is sure to have those.
I had to fabricate the shims for a Jag when I was sold a basket case when I was 15. It was the year I began learning to machine. In this case, a lathe, a heat treating oven, a surface grinder, and hand polishing techniques.

It worked, and I was able to part.out the basket case with engine for enough profit to help fund my first airplane...a Pacer, for 4200.
 

pictsidhe

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I had to fabricate the shims for a Jag when I was sold a basket case when I was 15. It was the year I began learning to machine. In this case, a lathe, a heat treating oven, a surface grinder, and hand polishing techniques.

It worked, and I was able to part.out the basket case with engine for enough profit to help fund my first airplane...a Pacer, for 4200.
Our most profitable machine at work makes $30,000 per day. It is 30 years old. We can usually get parts, but they tend to take weeks to come. I make or improvise a lot of parts for it...
 

TFF

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I think no one who has ever adjusted valves on a Jag, Alfa, Fiat, or Lotus and went to a Pep Boy’s and asked for parts for those. Anyone who ever has worked on those knows where every part in their area is. Much better support and the part owner probably discounts when paying in beer.
Pep Boys is for changing oil on some Hyundai for your daughter because their boyfriend can’t figure it out.
 

Hot Wings

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I think no one who has ever adjusted valves on a Jag, Alfa, Fiat, or Lotus and went to a Pep Boy’s and asked for parts for those.
Way off topic but....
The weirdest valve adjustment I ever had to make was on a DB-5 that needed a valve regrind. Probably part of the reason it needed a valve freshening is that there is NO way to adjust the valve lash other than grinding the stems after assembling the head and measuring the lash - if there is any after the valve work.

IMHO 007 was lucky to have survived that ride.
 

pictsidhe

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Way off topic but....
The weirdest valve adjustment I ever had to make was on a DB-5 that needed a valve regrind. Probably part of the reason it needed a valve freshening is that there is NO way to adjust the valve lash other than grinding the stems after assembling the head and measuring the lash - if there is any after the valve work.

IMHO 007 was lucky to have survived that ride.
I've seen that on a small industrial engine on a cement mixer. Flat head, either grind the stems or the shimless lifters...
 

Vigilant1

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I think no one who has ever adjusted valves on a Jag, Alfa, Fiat, or Lotus and went to a Pep Boy’s and asked for parts for those.
Sorry for any miscommunication--my comment was meant as a wry observation, not advice that those needing obscure foreign parts seek them at Pep Boys. It's just that, from my vantage point in the USA, the idea that if I couldn't find a Jaguar valve shim that I could easily find a Lotus Cortina valve shim was funny. Probably makes good sense in England, but in the US it is like saying "if you need a 1/4" x 1 3/8" cotter pin and don't have one, remember that the micro retainer pin on the lunar module landing foot pad can be easily used in a pinch."
 

Hot Wings

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Put the EX port to the out side and and the IN port towards the V and make it universal (heads up or down, pusher or tractor, flywheel or PTO drive).
Universal would be ideal - but more work than I care to take on in the near future.
If we could get a custom cam (could be made up using all stock bits form the built up pressed together cam) then making the heads swap-able from side to side looks workable.

You and I are both crawling down this rabbit hole on our backs. I'm most interested in developing for the inverted use.
 

Vigilant1

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The 10" dia spinner does quite a good job of covering most of the chunkiness of the block and ancillaries. Heads down is certainly going to make for nicer cowl lines, but the price for that is still unknown.
Thanks for the eye candy, it is motivational!
 
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