Tribute Act

[mtskull]

By the way, don't those little turboprops have a free turbine to drive the prop? Or are they direct drive?

There's no free power turbine but it's not direct drive as such; on those little Garretts the prop is driven via a reduction gearbox which is in permanent engagement with the shaft on which are mounted all the compressor and turbine blades. Therefore everything rotates together, which is why there's a heck of a lot of inertia and a heavy load on the batteries when you start it up.

[Renegadenemo]

I actually found a really good cutaway pic of one because of course I had to know...

http://en.wikipedia.org/wiki/File:Turboprop_cutaway.jpg

On a slightly different note, we just discovered why our air start valve was only delivering 150psi instead of 250psi and fixed it. Now we've not tried it yet because the engine is upside down having its fuel system installed but even on the lower setting it's terrifying! Another 100psi is going to explode something! It's little wonder they were all scared of it in 66.

I'll be setting the output pressure on the HP compressor, rigging a camera then taking the go-button into the safety of a different building on the end of a very long wire.

[rob565uk]

Bill

I am ahead of you there (probably for the first and last time!)..... I have already made up a remote start button and will bring it up on the next visit.

[Jordangbr]

That'll be a long pole with a finger on the end then?

[Renegadenemo]

I am ahead of you there (probably for the first and last time!)..... I have already made up a remote start button and will bring it up on the next visit.

Pleased about that. The start system is the only part of K7 that's genuinely dangerous. I mean, yes, a gas turbine is quite a violent piece of kit but also a known quantity in so many ways and we have world-class advisors on that one anyway. Boats - well K7 is a little different but we've been around boats and water (usually under it) for a lifetime and K7 is the best example of her type ever built so she isn't too scary either.
But that damned start system... It scares the bejesus out of me every time.

[rob565uk]

That'll be a long pole with a finger on the end then?

What you do in the privacy of your own home is entirely up to you

[Richie]

and there was me thinking Rob was going to get suited up in a ballistics suit then whilst tilting his head away from the rig and wincing....he can press the go button

[DamienB]

250 psi? You big girl. Watching someone put 1500 psi on a 1200 psi hydraulic system I retired to a safe distance. I doubled it and added a fire engine to hide behind when I heard them say "Still not moving - up another 500 please". Bit of a bang and hyd everywhere shortly afterwards, naturally.

[Renegadenemo]

250 psi? You big girl

It's not the 250psi that I don't like, it's the other 1500 sitting quietly in the bottles wishing it was out.

And give me hyd oil every time! I spent my youth on heavy plant and got hosed down a few times but HP air is a different gether all to case... the first time the HP hose or the o-ring blows on your diving bottle you get the idea.

In actual fact I don't view the start system as inherently dangerous. A lot of work has gone into making it safe. If I thought it presented any real danger I wouldn't put air into it. It's just that of all the things from the boat that could do a lot of damage if something did go wrong, the start system is top of the pile.

[Dominic Owen]

I think the thing with compressed air in a metal container is that you can't see or feel the pressure and the mind is inclined to wander with the consequences of it all getting out at once. If it's in something with a little more 'give', you can give it a prod and fool yourself into a little reassurance.

A friend of mine has a portable air tank in his workshop for inflating tyres that aren't within reach of the compressor. It only holds 120psi but is rated to twice that and has a large safety valve that opens at 130psi. You should see how many people still wrap it in cotton wool and carry it at arms length when it's full though. I once waited for a quiet moment and deliberately filled it until the valve opened - I don't think I've ever seen everyone move so quickly!