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Old 12 January 2005, 10:33   #11
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The Westland Gazelle is powered by a Turbomeca Astazou turboshaft engine (for the uninitiated that's a jet engine with a shaft drive). Jet engine combustion chambers are continuous combustion (no pistons) and run on a very wide range of fuels compared to piston engines. OK - nothing to do with RIBs, but be careful what you deduce from this comparison - it doesn't mean the fuels are that similar.
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Old 12 January 2005, 13:33   #12
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Quote:
Originally Posted by Nuts
The Westland Gazelle is powered by a Turbomeca Astazou turboshaft engine (for the uninitiated that's a jet engine with a shaft drive). Jet engine combustion chambers are continuous combustion (no pistons) and run on a very wide range of fuels compared to piston engines. OK - nothing to do with RIBs, but be careful what you deduce from this comparison - it doesn't mean the fuels are that similar.

Absolutly right!!. It is costing a huge amount of money to develop the engine to run on diesel. Its completly different to F44/JP5.
(I did all the Trials work for the optimax JP5 engines in the uk by the way)

To get the Engines to run on diesel you have to alter compersion ratios ignition mapping and lubrication systems etc etc.Im not allowed to say how its done but its cost well over a million Quid to do so far. Its actually very complicated.
The big problem with diesel is that after a few hours the piston rings get stuck because of all the carbon, the spark plugs also get totally covered.

Helicopter engines are quite alot different than outboard motors, luckily i used to be an Aircraft engineer before i started playing with boats so its good to know how both work!
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Old 12 January 2005, 15:06   #13
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If a helicopter can spin its rotor blades using a gas turbine, then is it feasible to fit one in a boat to drive the prop?
I know they come in all sizes, I have seen them in model aircraft.
How about this one.

http://cgi.ebay.co.uk/ws/eBayISAPI.d...548558930&rd=1

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Old 12 January 2005, 15:14   #14
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Yep, Mercury have made a gas turbine outboard. Its somewere on a website that i cant remember.
My boss had a go on a boat with it on when he was out in the states last year.
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Old 12 January 2005, 15:17   #15
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I have just looked at the video clips attached to the ebay item, and I am rather surprised to see that the frame he has the turbine fixed to is on wheels.
I can just see it whizzing off down the driveway.
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Old 12 January 2005, 15:20   #16
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So, they have the advantage on power to weight ratio, but I dont know what the downside is.
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Old 12 January 2005, 15:52   #17
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Dare I mention boatmad.com, there has been a thread running on there for a while based around the build up of this guys Gas turbine powered boat.

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Old 13 January 2005, 06:59   #18
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Quote:
Originally Posted by Nuts
The Westland Gazelle is powered by a Turbomeca Astazou turboshaft engine (for the uninitiated that's a jet engine with a shaft drive). Jet engine combustion chambers are continuous combustion (no pistons) and run on a very wide range of fuels compared to piston engines. OK - nothing to do with RIBs, but be careful what you deduce from this comparison - it doesn't mean the fuels are that similar.
I am well aware of that - have dabbled with gas turbines for years. Granted Diesel is not the same as the others but most of the fuels with JP designations are pretty close!!! Also as I said central heating oil is Kerosene which is the same stuff!!!
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Old 13 January 2005, 08:03   #19
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Quote:
Originally Posted by Turbodiesel
Absolutly right!!. It is costing a huge amount of money to develop the engine to run on diesel. Its completly different to F44/JP5.
(I did all the Trials work for the optimax JP5 engines in the uk by the way)

To get the Engines to run on diesel you have to alter compersion ratios ignition mapping and lubrication systems etc etc.Im not allowed to say how its done but its cost well over a million Quid to do so far. Its actually very complicated.
The big problem with diesel is that after a few hours the piston rings get stuck because of all the carbon, the spark plugs also get totally covered.
Surely JP5 is closer to diesel than it is to petrol??? I can quite understand the problems to get a low compression engine to run on anything other than petrol!!!
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Old 13 January 2005, 08:08   #20
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Quote:
Originally Posted by codprawn
...I can quite understand the problems to get a low compression engine to run on anything other than petrol!!!
I presume you mean, ... can't quite understand....


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