FD3/64-2:1!
Moderator: Mike Everman
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Re: FD3/64-2:1!
Hi Anders
With low pressure ratio combustors they certainly need to be larger , combustors are compared by their "combustion intensity " .....BTU's / cubic foot/atmosphere/hour , so if the "atmospheres" ie pressure , is low , then the cubic feet need to be greater to compensate .
The engine shouldn't run any "hotter" , the ultimate temperature will depend on what the turbine wheel can survive , but what will be "relatively" hotter is the exhaust due to there being a small pressure ratio across the turb stage and jet nozzle resulting in less temperature drop occuring for the same TIT as a higher pressure ratio engine , .................less pressure/temp drop means less power
OT , .................LOL.....with a compressor sucking >200 hp from the turbine , an extra hp or 2 for brass bushes and thrust bearing , is kinda irrelevant ...............balls at high rpm create a lot of drag , so theres not such a big difference between them and "brass" , balls are best at those lower initial spoolup rpm , thats why they're better on performance automotive turbos where you want every last millisecond of turbo lag to be eliminate, but for us , we're idling at a decent "boost" , so that advantage the balls have is negated to a large extent .
Cheers
John
With low pressure ratio combustors they certainly need to be larger , combustors are compared by their "combustion intensity " .....BTU's / cubic foot/atmosphere/hour , so if the "atmospheres" ie pressure , is low , then the cubic feet need to be greater to compensate .
The engine shouldn't run any "hotter" , the ultimate temperature will depend on what the turbine wheel can survive , but what will be "relatively" hotter is the exhaust due to there being a small pressure ratio across the turb stage and jet nozzle resulting in less temperature drop occuring for the same TIT as a higher pressure ratio engine , .................less pressure/temp drop means less power
OT , .................LOL.....with a compressor sucking >200 hp from the turbine , an extra hp or 2 for brass bushes and thrust bearing , is kinda irrelevant ...............balls at high rpm create a lot of drag , so theres not such a big difference between them and "brass" , balls are best at those lower initial spoolup rpm , thats why they're better on performance automotive turbos where you want every last millisecond of turbo lag to be eliminate, but for us , we're idling at a decent "boost" , so that advantage the balls have is negated to a large extent .
Cheers
John
Re: FD3/64-2:1!
Update
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Re: FD3/64-2:1!
It is looking better and better!
Re: FD3/64-2:1!
Thank you.
Here is the result of yet a coupple of well spent hours
This is the hardest part to make in my opinion. Its about 40% completed in this stage.
Here is the result of yet a coupple of well spent hours
This is the hardest part to make in my opinion. Its about 40% completed in this stage.
Re: FD3/64-2:1!
Finished cutting out, sanding and finaly welding the NGV blades today. This simple procedure took about 6 hours...
The 1mm stainless steel that the vanes are made of is hard to cut, but ok to sand/grind.
The result is not perfect, but hopefully good enough.
Next step is to make the shaft locator that will slide into the place currently
occupied by the plywood jig.
The 1mm stainless steel that the vanes are made of is hard to cut, but ok to sand/grind.
The result is not perfect, but hopefully good enough.
Next step is to make the shaft locator that will slide into the place currently
occupied by the plywood jig.
Re: FD3/64-2:1!
Update; finally finished the NGV parts!
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Re: FD3/64-2:1!
Have you given the material thickness any thought? Relatively large NGV areas and only 1mm stainless sheet, won´t there be a risk of heat warping?
Nice work anyway, looking forward to the first test video!
Nice work anyway, looking forward to the first test video!
Re: FD3/64-2:1!
I simply took the material I had laying around in my work shop, but you are right, it might become a problem.
The curvature of the blades gives them a little extra rigidity though, and they give a more trust worthy impression IRL ....
There are so many things that can go wrong.....
Today I have made a air inlet (trumpet shaped) cone of glass fibre, still in the curing process.
I’m currently working on the fuel delivery ring dimensioned for propane.
The curvature of the blades gives them a little extra rigidity though, and they give a more trust worthy impression IRL ....
There are so many things that can go wrong.....
Today I have made a air inlet (trumpet shaped) cone of glass fibre, still in the curing process.
I’m currently working on the fuel delivery ring dimensioned for propane.
Re: FD3/64-2:1!
Update.
I made some progress today as well
I made some progress today as well
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Re: FD3/64-2:1!
Looking good Axel!
I'll be following this thread!
I'll be following this thread!
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Re: FD3/64-2:1!
It is starting to look like a gas turbine now, nice work!
Have you calculated the max revs of the compressor, and if so how did you do it?
Have you calculated the max revs of the compressor, and if so how did you do it?
Re: FD3/64-2:1!
Thank you for your support guys!
Regarding compressor rev, i just assume, and hope, that it will be able to take half of the original designs rpm:75000rpm/2.
According to Shreckling it is the inner part, "the leading edge" of the compressor blades that will fail first, so adding more carbon fibre around the compressor is not the solution. The compressor he made has survived 90.000rpm as well so 75.000 include a safety margin.
Regarding compressor rev, i just assume, and hope, that it will be able to take half of the original designs rpm:75000rpm/2.
According to Shreckling it is the inner part, "the leading edge" of the compressor blades that will fail first, so adding more carbon fibre around the compressor is not the solution. The compressor he made has survived 90.000rpm as well so 75.000 include a safety margin.
Re: FD3/64-2:1!
Since I had a couple of mini sparkplugs laying in a box doing no good, I decided to mount one of them in the combustion camber. The size of this motor makes it easy to add such things...
Right now I am working on the shaft tunnel. In this first attempt I will try to build it by welding several pieces of aluminium together. If this does not work I will turn it down from a solid cylinder instead. It’s just such a waste of material.
Right now I am working on the shaft tunnel. In this first attempt I will try to build it by welding several pieces of aluminium together. If this does not work I will turn it down from a solid cylinder instead. It’s just such a waste of material.
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Re: FD3/64-2:1!
It is never a waste of material if you build gas turbine parts out of it.
Re: FD3/64-2:1!
The first version of the shaft tunnel is coming along fine. It’s not at all difficult to weld aluminium as long as the argon gas keeps flowing. I always thought it was close to impossible to weld aluminium at home using a ordinary mig-mag machine..