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Post by enginewhisperer on Apr 22, 2024 16:10:54 GMT -5
There are some fancy high power capacity belts available these days, but I've still had issues with those at much lower power and rpm than this thing! Some motorbikes use a belt instead of a chain, but the belt manufacturer recommendations specify much larger belts needed even at those loads.
Speedmaster is a pretty dodgy company. Most of their stuff appears to be knockoffs of other peoples products, made cheap in China. I actually bought one of their dry sump oil pumps that was on special, and it was junk. I sent it back.
So I wouldn't trust their specs at all!
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Post by enginewhisperer on Apr 18, 2024 0:28:55 GMT -5
what's the history of the battery? it might have just given up. They seem to do that sometimes. They'll work normally and then suddenly have no capacity.
It could still be a connection or cable problem though.
I had a similar thing with a 12v water pump the other day. It would run briefly at normal power and then die off. It's run from a large car battery with a solar charger. It appeared that the solar charger unit was causing issues. The battery would hold voltage but the output to the pump would drop to nearly nothing. Decided to fix it another time.
The next time I tried it it seemed to work fine!
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Post by enginewhisperer on Apr 12, 2024 0:21:13 GMT -5
that's definitely possible (brushes wearing in) usually they start off with a pretty flat end profile and wear into the commutator shape a bit over time - so they'd increase in contact area.
The bearings and gearbox might also have freed up a bit?
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Post by enginewhisperer on Apr 7, 2024 4:19:10 GMT -5
Realistically, most turbine engines have much higher mass flows than most turbochargers.
Even the RC turbojets have very large compressor wheels for the engine's overall size and weight when compared to a turbocharger. It would be hard to get more than the engine's weight in thrust out of a turbocharger setup.
In the end you're using 1/3rd of the air to generate power, at a low pressure ratio. It's just not very efficient, so you need a big engine to make much power.
The jet nozzle will also affect thrust massively - but if your turbo is not well suited to being a jet engine you won't be able to increase exhaust velocity enough with the nozzle before you run into compressor surge or turbine inlet temperature issues.
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Post by enginewhisperer on Mar 26, 2024 16:50:29 GMT -5
you need an abrasive NGV ring so the turbine can clearance itself That would be nice, perhaps add a diamond dust coating to the blade tips so they wear a track for themselves in the metal. I've seen some turbos with a nylon wear surface in the compressor housing to allow them to self clearance. Might be a bit harder to do on a turbine!
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Post by enginewhisperer on Mar 24, 2024 20:31:15 GMT -5
you need an abrasive NGV ring so the turbine can clearance itself
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Post by enginewhisperer on Mar 18, 2024 20:59:40 GMT -5
that's pretty cool!
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Post by enginewhisperer on Mar 13, 2024 20:56:27 GMT -5
depending on the pump you may find you don't need a regulator, but it can be harder to start the engine with high oil pressure when cold. A ball valve and return will work but you'll have to keep an eye on the pressure.
I have used an adjustable fuel pressure regulator for this purpose in the past and it worked fine. You can also set it up to increase pressure with "boost" to let you run a lower pressure for starting.
If you're using compressed air you need it to impinge on the compressor wheel and spin it to generate enough flow. Usually the easiest method is a large leaf blower, but it may need modification to get enough pressure.
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Post by enginewhisperer on Mar 10, 2024 23:03:07 GMT -5
Just an FYI...the final gear ratio is made with the tiny drive gear on the torque convertor to the giant gear on the flywheel. Without the giant flywheel gear, I am not sure what the reduction will be. Hopefully it's enough that the next stage can be done with some available gears or even a chain reduction. If it's driving into an existing car gearbox it might work ok just to use a low gear - even if the gearbox life span is a bit reduced due to high rpm.
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Post by enginewhisperer on Mar 10, 2024 22:59:37 GMT -5
Do you have a website?
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Post by enginewhisperer on Mar 10, 2024 3:08:52 GMT -5
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Post by enginewhisperer on Mar 9, 2024 5:17:59 GMT -5
As John said, I think a truck freepower unit would be a good starting point. They have a nice turbine with the primary reduction gearing.
You can probably get a complete setup with the original turbo, which might be suitable for the gas generator side of things.
The Detroit DD15 turbo compound units are often reasonably cheap on ebay and look to be a good starting point. The freepower makes 60hp in the truck application apparently.
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Post by enginewhisperer on Feb 27, 2024 17:52:21 GMT -5
Do you have the specs of the turbo? Chances are the compressor to turbine sizes are a bit mismatched for turbine use.
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Post by enginewhisperer on Feb 5, 2024 0:54:20 GMT -5
VW Beetle cooling fans are a simple sheet and tab / weld construction, and they run up close to 10,000rpm in standard form. People have apparently run them faster than that too. offroadvw.net/tech/wes/fan.html
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Post by enginewhisperer on Feb 4, 2024 23:15:02 GMT -5
these stresses seem much worse than I'd have guessed.
How does it compare to things like car engine flywheels or auto transmission flex plates? They're often ~300mm diameter and ~2mm thick with a starter ring gear on the outside - which is often pressed on! Most of them don't need to handle 10krpm, but they often do 8-9krpm, and practically everything does well over 4000rpm.
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