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Post by enginewhisperer on Mar 20, 2014 16:51:30 GMT -5
basically, if you can't TIG it, it's not worth welding
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Post by enginewhisperer on Mar 6, 2014 20:51:37 GMT -5
one day I will come to this event!
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Post by enginewhisperer on Feb 24, 2014 2:04:14 GMT -5
ahhhh that's no good! Very easy to do though...
It was a very impressively fast build. At least you'll get some more testing time and can have it running 100% definitely for the next race
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Post by enginewhisperer on Feb 18, 2014 22:47:31 GMT -5
bit hard for us to make our own like that
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Post by enginewhisperer on Feb 18, 2014 22:46:14 GMT -5
that is looking ridiculously awesome!
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Post by enginewhisperer on Feb 17, 2014 23:27:48 GMT -5
I was tempted by these too A triple turbine engine would be pretty cool!
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Post by enginewhisperer on Feb 17, 2014 23:24:20 GMT -5
yep,
air in ----> add energy /expand air ----> spin turbine to drive compressor ----> use remaining energy for thrust and / or freepower tubine.
The colder the air coming in the more energy you can add to it by combustion. Cooling the air after the compressor is robbing it of energy - which you would need to replace by burning more fuel to achieve the same turbine inlet temp.
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Post by enginewhisperer on Feb 17, 2014 23:16:07 GMT -5
The thing is a lot of the air in a turbine engine is not used to burn the fuel - but the overall ratio is there to keep the temperatures under control. You can't burn more fuel in the same amount of air without things getting too hot. Increasing the pressure ratio means you can get the same power out of less fuel - but you can't get a lot more power from the same sized engine / mass flow.
The easiest (and only) way to get more power is to increase the mass flow - which means a larger engine.
In theory if you could cool the turbine and combustor parts you could run higher turbine inlet temps, and maybe make more power - but all that heat you have to remove from the metal is lost energy, and therefore efficiency.
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Post by enginewhisperer on Feb 15, 2014 12:27:55 GMT -5
thanks I'll probably at least test with LPG since I have a working setup from the previous engine using the same combustor - but I will try to get another Dart fuel injector and set up a high pressure pump for diesel. Otherwise a large centrally mounted evaporator is probably possible with minimal mods to the combustor
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Post by enginewhisperer on Feb 14, 2014 23:09:44 GMT -5
This is the boat. It's suitably pointy: And the Dart combustor liner: And the new spark plug mount I machined up, including a super long electrode spark plug. In the past I used a modified "normal" spark plug, but it didn't really protrude far enough into the chamber for reliable ignition. I'm still deciding whether to use LPG as fuel - which is obviously very easy for delivery, and forgiving for combustion and ignition. If I use a car LPG tank it's also the cheapest fuel per litre to buy - which may become important if I actually want to use this thing!
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Post by enginewhisperer on Feb 14, 2014 23:02:49 GMT -5
Decided to start a thread on this since I'm stuck in the USA for work at the moment and can't do any jet building I recently acquired a ski boat, complete with a trailer and all the drive train and steering hardware minus the engine. Plan A was to install a sensible engine, but while on the way to pick up a heat exchanger for the cooling system I thought maybe I should resurrect my turbine engine project. I'd built a couple of engines using fairly small car turbos, and had mostly built a larger one using a Rolls Royce Dart combustor can and a large diesel turbo. Numbers suggest it should have been possible to make about 60hp with it (thanks Racket!) and I have two of those turbos - although one has some comp wheel damage. As soon as I got home I did a quick ebay search for "giant turbo" or similar, and turned up what appeared to be a CAT branded GT6041 (again thanks to Racket for the identification help!) I asked the seller for some measurements, and it definitely appeared to be a 6041 variant - so I bought it, for $200. Here it is next to a GT2871R: You know it's serious when it has a cast iron comp cover! So, combined with the Dart combustor after some minor mods - it should be a pretty decent gas generator! The hardest part will be the freepower setup, especially the gearbox - so I'm on the lookout for suitable gears. I'll need somewhere between 6:1 and 10:1 ratio. I want to pull apart an automatic transmission and see if I could use the planetary gearsets to make a simple 2 stage reduction. It will need some serious forced lubrication to handle the rpm, but it should be possible. At least boats don't tend to have too much shock loading.
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Post by enginewhisperer on Jan 11, 2014 5:44:09 GMT -5
here's a video of the jet running with that turbo. youtu.be/xsM5OjX-oN4It's using a Rolls Royce Dart combustor can, which I tested to hopefully reduce the TOTs, but it was the same as the old combustor, which was super basic and made from an old car exhaust resonator
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Post by enginewhisperer on Jan 10, 2014 5:47:30 GMT -5
I have used one of those turbos for a GT before. It worked, but the turbine is a bit small for the compressor size and TOT was very hot (700+°C) no matter what I did with the combustor. I also sheared the blades off a turbine wheel, probably due to a combination of surge and overheating.
I swapped that turbo for one from a Mitsubishi Cordia (or maybe Starion). It has a huge turbine compared to most car turbos, and worked really well, with TOT around 550°C
I also had some success with a Toyota CT20 turbo - but I'd recommend a CT26 if you can find one.
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Post by enginewhisperer on Nov 29, 2013 18:59:39 GMT -5
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Post by enginewhisperer on Nov 19, 2013 6:12:54 GMT -5
I am happy to put Fat Mumma on some inappropriate vehicle In all seriousness, I just obtained a free Fiat X1/9....
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