Pic of the Day

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Black Knight
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Re: Pic of the Day

Post by Black Knight »

That canopy really completes the look. Awesomeness :o

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Richie
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Re: Pic of the Day

Post by Richie »

Folks, you really have no idea, the images do this thing zero justice (referring to the boat and the cradle)

she is a monster to behold !
"You can screw a man down until he takes to drinking......take me to the fantastic place..."

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Renegadenemo
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Re: Pic of the Day

Post by Renegadenemo »

The part l really didn't enjoy was hanging the boat from the ceiling to get the cradle underneath. Yikes, that was scary!
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Renegadenemo
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Re: Pic of the Day

Post by Renegadenemo »

A further idea for the Starter would be to just have a simple orifice, to restrict flow & drop the pressure, in the Starter inlet (or before it) - instead of the plate - the idea being to drop the pressure to around 40psi, at the inlet to the Starter turbine.
The problem there is that all the delivery plumbing is for the HP setup so it's all inch bore and that's without all the valves and convolutions in the pipework. It's easy to turn the pressure down to 40psi but the plumbing then won't flow sufficient volume to be of any use. To get sufficient volume down the pipe we need to push it with higher pressures but then it expands inside the start turbine case and mostly escapes around and past the turbine without doing any useful work. Indeed, condensation can be seen forming a foot ahead of the turbine exhaust showing that the gas is still expanding all the way out there. it's incredibly wasteful. The answer looks to be the hybrid LP/HP starter with the nozzle plate. That way the gas can only expand directly out of the nozzles and onto the turbine vanes. It must form an orderly queue to get out of the case and must go via a vane on the way. Our current nozzle plate doesn't have an o-ring seal around its outer edge so we have a loss there but initial tests suggested it halved our gas consumption for the same engine speed. The noise it makes, however, is horrendous. an awful ear-piercing scream.
I'm only a plumber from Cannock...

"As to reward, my profession is its own reward;" Sherlock Holmes.

'Sometimes you gotta be an S.O.B if you wanna make a dream reality' Mark Knopfler

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Engine 711
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Re: Pic of the Day

Post by Engine 711 »

Renegadenemo wrote:
Mon Jun 25, 2018 2:29 pm
The problem there is that all the delivery plumbing is for the HP setup so it's all inch bore and that's without all the valves and convolutions in the pipework. It's easy to turn the pressure down to 40psi but the plumbing then won't flow sufficient volume to be of any use. To get sufficient volume down the pipe we need to push it with higher pressures but then it expands inside the start turbine case and mostly escapes around and past the turbine without doing any useful work. Indeed, condensation can be seen forming a foot ahead of the turbine exhaust showing that the gas is still expanding all the way out there. it's incredibly wasteful. The answer looks to be the hybrid LP/HP starter with the nozzle plate. That way the gas can only expand directly out of the nozzles and onto the turbine vanes. It must form an orderly queue to get out of the case and must go via a vane on the way. Our current nozzle plate doesn't have an o-ring seal around its outer edge so we have a loss there but initial tests suggested it halved our gas consumption for the same engine speed. The noise it makes, however, is horrendous. an awful ear-piercing scream.
OK. That makes sense. I would put any orifice as close to the Starter as possible, so that the pipework is still as high a pressure as possible.

The LP Starters and Start valves I worked with (Trents & 211's), had connections around 3 inch diameter - in order to flow enough air at 40psi to actually work. The start valves were butterfly types, mounted fairly close to the starter - sometimes even right on the starter inlet. In contrast, the HP systems (Olympus) were around 1 inch or 1.5inch diameter. Could even have had common parts with K7's system.

The HP starter sounds like it was a Impulse turbine, with HP air being 'shot'/expanded through fixed nozzles directly into the turbine rotor (so there are no stator vanes) - whereas the LP starter was probably more of a Reaction (*) Turbine, with a set of stator vanes before the rotor (which increase the velocity of the aire, before it goes into the rotor, where it expands).

(* - strictly probably a 50% Reaction/50% Impulse Turbine - which is normal for gas turbines)

You could perhaps add an O-ring to better seal your plate....? The awful scream is probably unavoidable..... ;)

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thunderer
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Re: Pic of the Day

Post by thunderer »

Any "scream" in relation to compressed air is unavoidable unless a "muff" (silencer) is utilised. It is the interaction between velocity of the air, the size of the orifice it is venting from and air turbulance that causes it. The higher the pressure, the higher pitch the "Scream" will be. The greater the volume of air, the longer it will last.

Working with compressors and compressed air taught me many things but most notably, that compressed air is a killer, even at low pressure. One other notable point is that when draining off a system/allowing air to freely vent to atmosphere quickly, you should always wear ear-protection as prolonged exposure to the higher pitch "scream" of escaping air can and will cause damage to your ears and induce early deafness.
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Re: Pic of the Day

Post by mark-f »

Does anyone know what happened to the original cradle? It was certainly still up at Pier Cottage in the mid 1980's. It was just outside the gate on the right hand side as you went in.

Black Knight
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Re: Pic of the Day

Post by Black Knight »

How far behind is pic of the day to the stage the boat is right now?

Black Knight
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Re: Pic of the Day

Post by Black Knight »

Thanks Mike, I was only wondering as following the pics then a video diary appears & that seems way ahead.

Black Knight
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Re: Pic of the Day

Post by Black Knight »

Is there a pic of the boat hanging from the ceiling???

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