Kasey
Well-Known Member
Has anyone built a small Judson type vane supercharger?
supershargers
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Bentwings
Well-Known Member
I searched the internet for blower and supercharger models. The screw blower has taken over the alcohol drag racers they are very expensive but can really put out boost for the big hemi motor sour ancient 6-71 and larger sizes are pretty primitive by comparison. Now the interesting part. A guy 3D printed a very nice model screw blower then powered it with an electric motor to see how it performed. Unfortunately it would not produce any boost or even significant air flow enough to inflate a garbage bag. These blowers tak ver precisely made rotors and tight clearances the 3dprinting process just can’t do this maybe if he had incorporated rotor sealed it might have helped he made a very nice video of construction and testing.
I continued and found a similar build of the 6-71 blower this guy works in a large shop that does aluminum casting. He walked through the process of making the after market 6-71 then he created a 3D printed1/4 scale 6-71 he also has several smaller scale models of these. These don’t require quite as close tolerances as you can see the dust and paper movement around the blower as he turns it over so it definitely will produce some boost. His models are nt too expensive so would be fun to play with in the shop. He has drawing files available too. Another site shows how to develope the rotors in cadd. Conceivably you could get files and 3D metal print a model one. It might be much more expensive however. But with files you can explore the 3D printing process. He also discuses this in his site
his company is diamond P industries. The files are in shape ways. I couldn’t find them but I think there is a contact number .
You can search under 1/2 scale 6-71 blower. He has been around for years so knows his way around construction. I think a division of his company is in the cutaneous. Anyway I think it would be best to create a model 6-71 positive displacement blower as it’s possible to CBC the rotors with a little enginuity. Even a1/4 scale one takes a lot of material to make from solid. Just modeling it will take some cadd skill. I have access to a near new 6-71 to measure so that’s on my list of interesting projects. You bold adapt this to about any model enginges and make serious boost. It will be a project in itself. We’re I to do it I’d gear or belt drive to run about 6k blower rpm and see what kind of boost you can get. The nice thing is that you can set it up for a standard draw through carb and only need a small fuel pump. Any way here is some cool info on his site
byron
I continued and found a similar build of the 6-71 blower this guy works in a large shop that does aluminum casting. He walked through the process of making the after market 6-71 then he created a 3D printed1/4 scale 6-71 he also has several smaller scale models of these. These don’t require quite as close tolerances as you can see the dust and paper movement around the blower as he turns it over so it definitely will produce some boost. His models are nt too expensive so would be fun to play with in the shop. He has drawing files available too. Another site shows how to develope the rotors in cadd. Conceivably you could get files and 3D metal print a model one. It might be much more expensive however. But with files you can explore the 3D printing process. He also discuses this in his site
his company is diamond P industries. The files are in shape ways. I couldn’t find them but I think there is a contact number .
You can search under 1/2 scale 6-71 blower. He has been around for years so knows his way around construction. I think a division of his company is in the cutaneous. Anyway I think it would be best to create a model 6-71 positive displacement blower as it’s possible to CBC the rotors with a little enginuity. Even a1/4 scale one takes a lot of material to make from solid. Just modeling it will take some cadd skill. I have access to a near new 6-71 to measure so that’s on my list of interesting projects. You bold adapt this to about any model enginges and make serious boost. It will be a project in itself. We’re I to do it I’d gear or belt drive to run about 6k blower rpm and see what kind of boost you can get. The nice thing is that you can set it up for a standard draw through carb and only need a small fuel pump. Any way here is some cool info on his site
byron
Kasey
Well-Known Member
Thanks Byron,
What I'm doing necessitates a vane type I believe, as I want a pulse charge timed with the opening of the 2 stroke port in an engine, to by-pass the crankcase so 4 stroke type lubrication via splash can be used. Some of them have self lubricating vanes and with a 2 vane compressor, it can run at half crankshaft speed. So far, mine is a mix of PLA and ABS with a steel shim liner in the housing. Runs very cool. Seems to work correctly, but is very noisy. Maybe that is why none exist today with engines.
I always heard Detroit 2 stroke diesels were a device for converting diesel into smoke and noise.
I did something similar on the rear of a tiny two stroke many years ago. Never found out if it worked.
I think the vane type died out in regular usage mostly because of the difficulty of adequately lubricating the vanes where they rub on the casing. For a model engine it's easy enough to add some 2-stroke oil to the fuel or add lubricant via a drip oiler, but in a modern automotive context it's not really desirable to use this sort of arrangement, especially if other options like a roots or screw blower can be used instead.
For the vanes I think either cast iron or phenolic laminate is preferred. Housing should be cast iron, and rotor steel.
I'm also interested in blower scavenged 2-strokes so I'm keen to see it running.
For the vanes I think either cast iron or phenolic laminate is preferred. Housing should be cast iron, and rotor steel.
I'm also interested in blower scavenged 2-strokes so I'm keen to see it running.
Kasey
Well-Known Member
I'm doing this on a split single design, where there is an extended time of port opening for both inlet and exhaust, that's why I thought a 2 vane positive displacement vane compressor should work. Vanes have improved much lately to be almost self lubricating, so a ratio of 100 : should keep the blower ok, while with a sealed c/c, splash Lub. may be adequate. That's what I/m trying for.
kop
Well-Known Member
Taken an air motor apart lately?
And from one of our favorite irreverent personalities.
I needed a small pump one day and didn't want to go to China Bay let alone to the box store. Since I had a surplus of air die grinders around (30 or more, it's a thing here) I took one apart and proceeded to make chips fly. Although these motors are usually axially fed there is no reason why they can't be radially ported. All you have to allow for is good vane support. Vanes in a radial ported motor/pump tend to wear a but quicker.
I made vanes from some carbon fiber sheet I found at the bobby shop although fiberglass and or PC-board would work. I actually cut a section off the air motor and butchered my way from there.
What I ended up with was a few PSI in a motor 3/4" long and about 1 1/8" dia. whizzing about @ 5000 rpm.
It takes a little patience to get a vane type pump to work well. Just refer to all the junque 12V air horn pumps out there.
And from one of our favorite irreverent personalities.
I needed a small pump one day and didn't want to go to China Bay let alone to the box store. Since I had a surplus of air die grinders around (30 or more, it's a thing here) I took one apart and proceeded to make chips fly. Although these motors are usually axially fed there is no reason why they can't be radially ported. All you have to allow for is good vane support. Vanes in a radial ported motor/pump tend to wear a but quicker.
I made vanes from some carbon fiber sheet I found at the bobby shop although fiberglass and or PC-board would work. I actually cut a section off the air motor and butchered my way from there.
What I ended up with was a few PSI in a motor 3/4" long and about 1 1/8" dia. whizzing about @ 5000 rpm.
It takes a little patience to get a vane type pump to work well. Just refer to all the junque 12V air horn pumps out there.
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I stumbled on the Saito FA-90T article showing a vane rotor. But maybe the purpose (pressure) for this particular one might be lower than supercharger boost.
http://sceptreflight.com/Model Engine Tests/Saito FA-90T MkII (2).html
http://sceptreflight.com/Model Engine Tests/Saito FA-90T MkII (2).html
Been reading this thread with much interest, would like to make a multi-cylinder 2-stroke with blower to avoid crankcase loop scavenge and allow splash lube. Looking at an EMD 645 series V8 as a likely contender for general arrangement in 1/8 scale but with port exhausts rather than valves as in the full size. Early days yet and needing to learn a lot more before committing to making swarf.
Kasey
Well-Known Member
Yours seems way more ambitious than mne. All I want is a 3 rod crank for a triple, but with a single cool running inlet rotary valve in the head, rotary valve along the cylinder exhaust ports for 2 stroke type exhausting..... but with 4 stroke operation, and internal lubrication. Haven't found any engine like that yet, but maybe someone has tried it?
Not quite the same, but I have an engine drawn up with some similar features.
Mine is a rotary, using a vane pump for induction, via a rotary valve (hollow crankshaft with a port on one side) to a cylinder wall inlet port. Exhaust ports are also in the cylinder wall and the engine runs as a 2 stroke, but with the option of separate oil for lubrication.
Have you looked at the Commer TS3 engine?
Pete.
Mine is a rotary, using a vane pump for induction, via a rotary valve (hollow crankshaft with a port on one side) to a cylinder wall inlet port. Exhaust ports are also in the cylinder wall and the engine runs as a 2 stroke, but with the option of separate oil for lubrication.
Have you looked at the Commer TS3 engine?
Pete.
Kasey
Well-Known Member
I'm familiar with the Commer Knocker if that is it. A Pope mower engine from the 1950's had a hollow rotary valve induction craaankshaft which was every effective. I'm finding the 2 vane charger I've built, very noisy however which is a real problem. To get away from a supercharger, I'd like to build a rotary valve head which does induction only to keep it cool, but with 2 stroke type exhaust, and 4 stroke function and lubrication. A seconfd small rotary valve on the exhaust ports running at half C/S speed can stop any induction loss on that stroke. Keeping it cool might be a problem tho'.
Might be worth looking at the Yamaha YPVS valves. They are used to alter exhaust timing, but the principle could be applied to fully close your exhaust ports.
Is the noise from the 2-vane charger mechanical or related to the compression and discharge of the air? There are some very quiet air conditioner compressors around these days that might offer some options but I imagine they are more designed for pressure than flow, where a blower for an ic engine is more for air flow than pressure. I was also wondering whether air pumps for large aquarium use might offer a possible design solution but have not investigated it yet.
Might only be a pipe dream, but hopeful that the concept is workable. I've started drawing it up but there are a lot of things to work out yet, not the least of which is how to build it. Would be a very large and complex casting if one piece. Might need to fabricate it in several bits which are then bolted together, much like my old VW Kombi engine with separate crankcase, cylinder barrels and heads all held together with long studs from the crankcase. So it would be like two inline 4 cylinder engines mounted side by side on a common crankcase sharing a crankshaft. VW did it with two V-6 engines to make the Bugatti Veyron engine, so how hard can it be???
Kasey
Well-Known Member
That complexity is why I'm working on a split single principle to apply it to a 3 journal c/s. Utilizing a BMW 3 cylinder 750 cc crank, it should be possible to build a 1500cc engine of either 2 or 4 stroke configuration with its own lub. and fuel injection from the bike motor and utilize its mechanisms to drive any other shafts for special valves incorporated in it. I have 2, 4 cyl. engines already for bits,but the 3 cyl. will be more compact and easier to work on and re-configure.
OK, so will you use two 3-cylinder 750cc engines coupled together to get your 1500cc? Would they be like a pigeon pair with a geared connection between the two crankshafts? Sounds like an interesting proposition.
Kasey
Well-Known Member
FAR FROM IT. Using only the pistons if possible , the crank, and a doctored version of the crankcase with the 3 cylinders removed along their base line and both ends; then onto that base , 3 pairs of twin cylinders can be mounted across it and on, in the " split single " configuration, each with its own "twin" head, and all air cooled for simplicity. I have radically changed the s/s coupled con rod design to allow for shorter rods with greater leverage at ignition. At present, I have a single,170cc crank engine running to experience what will be needed for building a proper bike/car or outboard engine of that type. The 3's crank should have good balance properties built in. I was intending to build a flat 4 (twin) at first but abandoned that for the single for a first try.
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Kasey
Well-Known Member
I think the main noise comes from each vane slamming back into the base of the vane slot in the rotor. On compression the vane is forced back into the rotor at high velocity with little room under it to slow down at the end of its inward stroke, for centrifugal force to change its momentum before it hits bottom. I've tried a hair pin spring and a rubber strip there but to no avail. On induction, as the vane flies out, the same may be happening against the rotor housing wall. Lightweight vane of ? material may be the answer.
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