Rallying gas turbines

On gas turbines, I feel we ought to be sorting out some rules for their
display at rallies. There are legitimate stationary engine applications for
them and there are an improbable number about for reasonable money - you
can pick up a running Rover fire pump for about the same as an unrestored
Amanco or Bradford open crank. The easy path is to ban them like gazebos at
Astle Park, but I feel it is unreasonable to do so when sensible measures
can be applied to make them safe.
I am fully seized of the dangers inherent in running an engine of unknown
provenance that rotates at perhaps 20,000RPM. Blades making a break for
freedom through the case are the real danger and even in aircraft
applications where the engine case is armoured, they are still known to
enter the fuselage on rare occasions. Just imagine the carnage if an
unshielded turbine broke up, spraying red hot blades about the place. That
said, there is little likelihood of engines on display being run up to
maximum RPM, so the actual danger is ameliorated to an extent.
I'd be prepared to correlate advice and suggestions into something for SEM
and I'm aware that this forum has a number of contributors who have spent a
lot of years around gas turbines. What do you think could be reasonably
achieved in order to make these interesting devices safe for public viewing?
Regards,
Kim Siddorn
Reply to
Kim Siddorn
Loading thread data ...
I should think the insurance costs for a vintage gas turbine being run by an amateur at a public show would be prohibitive at best, more likely is that it would be impossible to insure so the organisers wouldn't consider it.
A nicely sectioned engine being turned over slowly would make a nice exhibit though.
Greg
Reply to
Greg
Personally, I'd prefer not to see them at rallies at all. They are a branch of internal combustion science which is not directly related to our piston engines, and like Hot Air engines have only a tenuous link to what we class as our hobby.
The insurance and safety aspects will become a problem when one eventually blows up, and then, like the Case Tractor at Medina, there will be a big clamour for 'this sort of thing' to stop.
I do find them interesting, but the dangers inherent in their operation make them an item better left as a 'glass case' exhibit.
Peter -- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk
formatting link
Reply to
Prepair Ltd
I think if you look into it they are running all these engines under exactly the same insurance as we run our engines !! I know the Merlins are, or were run under the same insurance, I think there is a far greater risk with these types of aero engines and their derivatives. I mean you cannot compare, for insurance reasons, an Amanco with either the dangers of those Merlin props or a turbine can you ?? Love to see them running but would hate to see the aftermath of an accident with one.
MartinH
Reply to
Martin Hirst
I've actually seen one of these engines being run at a rally and was impressed by the noise and spectacle. Indded I hoped to see more such exhibits. Then I started finding out about their failures and now must agree with Peter.
These engines are run to be spectacular and that means full speed. There are many cases of rotors bursting on proffesionally maintained modern aircraft engines. These engines are regularly inspected, X rayed, tested etc by pro's with specialised equipment and they can still fail. What chance do we stand in our sheds and garages.
If (when) one lets go, people might well be injured or killed. That would reflect on the rest of us as the accident would simply be "Engine at steam fair kills X people". Our insurance is presently almost =A30. I pay =A312/yr club subscription and that gets me newsletters, meetings, etc. We could suddenly find we're not allowed to run our vintage engines in public at all. Possibly not even in private, although that would be generally uneforcable.
There is a turbine at Internal Fire awaiting restoration and susequent running. Paul is well aware of the risks and is taking suitable precautions such as a concrete building and excluding people while it's running. Not the sort of thing we can do at a rally.
These engines present too great a risk to be run in public by amateurs.
John
Reply to
John
I don't think a GT needs to be run at anything like full speed to be spectacular. A Derwent will run quite nicely at a bit under 2,000RPM and a Palouste I saw demoed was pretty impressive just spooling up before ignition! Model GT's are readily available, spin reliably at high RPM & are in use all the time by model aircraft clubs and increasingly by skydivers.
I agree that piston aero engines demoed at steam rallies look pretty hairy & one should not forget that a Merlin supercharger is running at (I believe) ten times engine speed. That said, they were incredibly reliable devices by the end of their development & although I'm aware that early failures were not unknown, I cannot recall failures in service sans enemy action.
Surely, a gas turbine cannot be seen as anything other than an internal combustion engine? I've not seen any qualifying notices saying "piston" anywhere & herein lies the difficulty.
As I said straight off the bat, we need to think about safety and how we could formulate a Custom & Practice that will ensure both the safety of the demonstrator, his mates and the general public. A steam roller ran away in a Devonshire lane and a traction engine boiler exploded in the USA, but I suspect that steam rallies are booked for the forthcoming season just the same. It can be done and we ought to be ahead of both the game and the inevitable failure.
Surely we can do better, gentlemen, than simply condemning the last fifty years of the development of an internal combustion engine to being silent museum pieces?
Regards,
Kim Siddorn
Reply to
Kim Siddorn
On Thu, 11 Jan 2007 14:28:18 +0000, Prepair Ltd finished tucking into their plate of fish, chips and mushy peas. Wiping their mouths, they swiggged the last of their cup of tea, paid the bill and wrote::
Forgive me for asking, but what happened to the Case tractor at Medina?
Brian L Dominic
Web Sites: Canals:
formatting link
of the Cromford Canal:
formatting link
(Waterways World Site of the Month, November 2005)
Newsgroup readers should note that the reply-to address is NOT read: To email me, please send to brian(dot)dominic(at)tiscali(dot)co(dot)uk
Reply to
Brian Dominic
I feel that 'being practical' is probably the thing rather than 'condemming', Kim. I love to get up close to a 747 engine, but not while it is running!
Peter -- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk
formatting link
Reply to
Prepair Ltd
Can I agree with you (and disagree with some of your respondents)? Imagine the carnage if a boiler expoded. Imagine the corrosion of steel in a hot wet environment. Yet traction engine rallies have dozens of boilers - and they are run at full pressure, not artificially restricted. And you can walk right up to them. We accept this because they have a history of safety and an established inspection programme. But as with aircraft (one of the safest forms of transport) there are accidents.
I'd like to see turbines run up at rallies. It should be possible to determine a safe operating procedure, (e.g. withdraw to a safe distance during running).
But I'd be careful about inventing too many rules and controls, in case your setiments backfire. Unknown provenance can cut both ways.
Wilfrid Underwood
Kim Siddorn wrote:
Reply to
Wilfrid Underwood
danger
think
Wilfrid Underwood wrote:
But Boilers have inspections on a regular basis, and are issued with a certificate. Even if they did that with a Turbine ( which on a personal level I would love to hear running ), the fallout from a disintegrating turbine would be so great that they would probably be banned instantly.
Unfortunately, I believe this is one of those cases where the smart move is to enjoy it yourself or with friends, but not the general public.
Reply to
Barry Ruck
Kim, I doubt that very much. IIRC about 6000RPM was idle and that won't be much above self sustaining RPM at that.
As a very good rule, a gas turbine won't run unaided below about 50% (core speed), they need starter assist below this to reach a self sustain RPM.
I've worked on many gas turbines, (from little APU's in 737's up to GE CF-6 and RB211) for years before starting to fly the things. To be honest I hate their horrid high pitched noise that easily damages your hearing, not to mention that even the smallest GT uses about 50KG's kerosene/hour! When running there is nothing to see, so you could hide a ghetto blaster under the engine and nobody would know the difference...
I think the possibility of an accident is real, like a Diesel engine the things are not speed stable and rely on governors, or fuel control units for stability. The maintenance and adjustment of these could be critical, and specialist knowledge/test equipment essential.
A good strong mesh over the intake would be good, something solid going into the compressor easily spells disaster, also make sure everyone stands well in front of the thing - blades and shaft discs come out the side!
Reply to
Julian
branch of
piston engines,
our hobby.
There are very few stationary engine only rallies and most people at general rallies would probably consider stationary engines to have a tenuous link to "their" hobby - s/e are usually stuck at the side or the back somewhere which tells what people think of "your hobby".
eventually blows
clamour for
Before suggesting banning other people and their hobbies it would be a good idea to put our own house in order. There are a number of larger engines attending rallies that I would not consider safely displayed. Also, how many times have you seen an inexperienced owner allow an over fuelled Petter to run away, potentially lethal 6ft from a bystander. How many exhibitors could tell you the safe max rpm of the cast iron flywheel on their engine, how many bother to check for cracks when they drag it out the bushes and run it up to 3 or 400 rpm.
Poorly fitted flywheel keys allowing a 1cwt flywheel to come off at 300 rpm - could easily kill a child standing nearby etc etc - I've seen it happen twice and I believe someone on this NG has even admitted to having it happen.
How many people attending with air start engines have bothered to get tickets on their bottles? Ever seen the results of a decent size bottle going pop at 300 psi?
For a GT to attend a rally it must be down to the organisers to ensure a safe display area away from the crowd with the plane of rotation parallel to the display line. Having a nominated "Engineering Safety Inspector" with a good engineering background would be a sensible idea but probably not a job anybody would fancy if it meant having to tell someone to go home.
Although there is no real way you can "police" exhibits, all organisers/stewards can do is to ensure that exhibits are displayed in an appropriate manner and that all possible precautions have been taken. If it looks dodgy, it probably is.
Having said all that I'm not convinced about GTs at rallies and would suggest a voluntary Code of Practice might not be a bad idea. That would also be a good idea for some of the larger i/c engines and might preempt more formal legislation being forced on us - pretty much the same thing as done by the hot fog brigade. Just because you know what you are doing doesn't mean the plonker next to you does.
"Personal hat" on.
Paul
Reply to
Paul Evans
====================================== I spent 35 years of my life on engine test at BS/RR and in that time never experienced a failure scheduled or unscheduled where the turbine disc was not contained . I've fired a 4lb chicken into a Viper running @13760 rpm ,3 inch iceballs into a M45.sand into a Pegasus etc etc,all very interesting and quite theraputic wrecking millions of pounds worth of engine in the cause of safety. With regards to gas turbines as rally exhibits I am not in favour only because all they do is make a noise,externally there is nothing moving. I would rather look at a Lister D running a water pump any time. Mike.H.
Reply to
Mike.H.
Had the same comment from all the ex Bristol engineers waiting to see the Proteus run here, the need for the strong containment is the 7 tons of rotor bolted to the front of the unit turning at 1500 rpm :-)
There were a number of failures in flight with the Proteus caused by ice forming on the inlet and being ingested into the compressor, been told by the guys involved at the time that there was no breach of the casing.
The one mod we are implementing though is a later type of fuel shutoff system which is much more positive.
Proteus turbines are still in service at a number of sites in the UK, over 45 years since the first installation. A number are at nuclear sites where diesel standby systems have been and gone.
Paul
Reply to
Paul Evans
Boiler explosion at a rally, killed 4 people including a couple of Police IIRC:
formatting link
Peter -- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:
formatting link
Reply to
Peter A Forbes
On Thu, 11 Jan 2007 20:22:21 +0000, Peter A Forbes finished tucking into their plate of fish, chips and mushy peas. Wiping their mouths, they swiggged the last of their cup of tea, paid the bill and wrote::
Thank you, Peter.
Brian L Dominic
Web Sites: Canals:
formatting link
of the Cromford Canal:
formatting link
(Waterways World Site of the Month, November 2005)
Newsgroup readers should note that the reply-to address is NOT read: To email me, please send to brian(dot)dominic(at)tiscali(dot)co(dot)uk
Reply to
Brian Dominic
An interesting topic that I feel I should add a couple of observations to:
A consultation with the Drag Racing and Tractor Pulling franternity may help with regulations on running turbines, and they tend to run them under max throttle conditions. Certainly the last time I was at Santa Pad they had a turbine on a trailer with the exhaust pointing downwards that they used to dry the track! As far as I could tell all they had was a few big signs saying motor sport is loud and dangerous with a disclaimer!
Would this also extend to turbochargers? I suspect that there will be a few turbocharged engines becoming exhibitable age before long, and a turbo disintegrating from 120,000+ revs can make a mess as well!
I think, in this day of health and safety trying to legislate common sense out of the equation, you could cause more issues - there were very few turbines acutally designed as stationary plants (including a Perkins unit), and with a bit of common sense, careful maintenance, and an operator who knows what they are doing there shouldn't be a problem. This is the case for any other piece of machinery being run in public from a garden strimmer upwards.
Regards Dan
Reply to
Dan Howden
Gentlemen,
I cannot add to the discussion other than I ere on the side of the against, what I will say is that the sort of GT that would likely be displayed would be the older engine which may have stood for a long period of time static. My point is that the cost of re-commissioning the engine to full working order would be to prohibitive to even consider it.
Martin P
Reply to
campingstoveman
I think people are overreacting here. Gas turbine engines are far more reliable than piston engines, just ask any pilot or airframe builder. With a few sensible precautions there is no reason why these engines should not be shown and run, albeit at low power to keep the noise below the levels which would require hearing protection for spectators.
OTOH, sensible safety precautions are certainly a good idea. Firstly a current safety certificate should be required, this is already a requirement for steam boilers. This is not an area where we should rely on unqualified maintenance without qualified inspection. Your comments regarding intake mesh are good, and such engines should always be orientated so that blades coming out of the side will not cross the crowd line. All modern turbines have a strong containment ring, maybe additional containment should be required for older engines.
Reply to
Chris Newport
Sorry, I was wrong about the 2,000 RPM & Ian Bennett says:- "The Derwent engine by virtue of it's large centrifugal compressor idles at just 3,500 rpm, so this helps to make the operation of it a bit safer. The Derwent produces very little thrust at low to medium rpm so our stationary example remained rooted to the spot at all times. Our engine did not have the Meteor propelling nozzle fitted to the exhaust so the maximum thrust was reduced and also the temperatures were kept down."
Have a look at his Derwent 8 here
formatting link
Further poking about brought me here
formatting link
Look at the third picture down & read the blurb - now THAT's unusual!
Regards,
Kim Siddorn
Reply to
Kim Siddorn

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.