I'm sorry, I was looking for uk.rec.engines.stationary and a thread on rallying gas turbines. Alas, I appear to have fallen in on the Old Ladies Knitting and Tea Society monthly meeting. However, I think I'll still post the following info on the off chance that there may be someone sporting a pair hiding in a corner under a tea cozy who may yet timidly venture out after all of those scary knitting needles are put away.
Across the pond, not only are gas turbines rallied, they're combined with cultural icons such as the La-Z-Boy chair to provide the ultimate in rally field transportation comfort combined with the convenience of easily cooking lunch.
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This AP-143 unit runs on a proprietary blend of a hops-based fluid and propane. This unique beast was designed and built by B&S LLC of Broussard, LA.
As I'm sure you can imagine, as the time nears to light this puppy off, the crowd excitement is nearly palpable. Some are totally overcome.
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Contact!!
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As the turbine spools up to full-thrust, you can see this wondrous beast straining hard at the safety-restraint chains.
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Do I detect surprise that safety would be foremost in our minds? Oh ye of little faith... These massive chains (and the iron bars) are more than up to the job.
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In any case, the crowds do seem to sense the potential for bodily harm and most do keep a respectful separation distance.
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Well, usually. Here you can see the smoldering, charred remains of one young lad's weenie roasting stick. We understand that he'll be released soon and that the scarring isn't expected to be TOO bad. OTOH, a safety-first approach WAS thought of. Notice the length of the stick...
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I'll monitor this thread for a few days and if it looks like you can handle the excitement, I'll post a link to the video of the event.
Cheers. Arnie
Arnie Fero Pittsburgh, PA USA fero snipped-for-privacy@city-net.com
While I respect your experience and certainly modern engines are very very safe, those engines you tested hadn't been left to rot for 40 years before being patched up by an idiot with a mig welder and car body filler!, you can get away with a lot when you're only patching up a Lister D but not when it's a GT.
Also the idea which has been suggested that it only has to be run slow is quite simply daft as a GT by it's nature has to be governed, and a failure can cause it to run away and explode. Greg
For better or worse, the laws about liability to the public are fundamentally different in this country and that inevitably colours peoples discussions. Greg
I'm very surprised and frankly very doubtful that they are running a Merlin under the same cheap insurance as a Lister D. The owner may be CLAIMING he is insured because he's in a stationary engine club and this is a stationary engine, but has anyone got it in writing from the insurer?.
Insurance companies are not daft and don't accept hugely increased risks without hugely increased premiums. The chances are if there was a claim the insurer would refuse to pay out on several grounds, the most obvious being that it's not a stationary engine it's an aircraft engine with a castrated propeller on the front!. There's also likely to be a lot of small print in the policy that excludes such an engine. Greg
I must admit that being close to any kind of large pressure vessel makes me a tad nervous, be it a boiler or air tank. But I draw comfort from the belief that they would not be at a rally if they didn't hold a current ticket - is that not the case for starting bottles?
BTW at One of the pulling tractors at Barleylands a couple of years ago was powered by a small helicopter turbine, so there must be some sort of precedent for what is insurable for public display.
I must admit that being close to any kind of large pressure vessel makes me a tad nervous, be it a boiler or air tank. But I draw comfort from the belief that they would not be at a rally if they didn't hold a current ticket - is that not the case for starting bottles?
BTW at One of the pulling tractors at Barleylands a couple of years ago was powered by a small helicopter turbine, so there must be some sort of precedent for what is insurable for public display.
I'm both, in general that is true. The point missed is that failure of a GT is often catastrophic, bits go for miles with the speed of a bullet. Remember the British Airtours Disaster at Manchester Airport 25ish years ago, that was just a combustion can letting go on a JT-8.
With a few sensible precautions there is
Nah, still as noisy as hell whatever the power, centrifugal compressors are especially noisy, have you walked infront of a RR Dart at idle? The noise really hurts you unless you insert fingers into ear 'oles as a minimum.
I'm qualified here, any sort of safety certificate would prolly be beyond the financial reach of a collector, it would be beyond my means.
. All modern turbines have a strong containment
Well, sort off. In general it tends to be just the fan on the large jets that have containment, the CF-6 has about 70 layers of kevlar IIRC. If an engine went bang big time, then bits and pieces would go in all directions, plenty would be red hot and also burning fuel and oil from disrupted fuel systems would figure in the equation.
I'm sure it would be possible to do these things fairly safely, but the average Joe running it up next to his Lister D worries me a fair bit.
There are numerous cases of uncontained rotor failure in the aviation industry. Admittedly they're rare when compared to the total number of flights but they do happen. These engines are professionally maintained to standards that we cannot even aproach, yet even so accidents happen and they're big ones.
Look at these sites:
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was caused because a NiCd plating layer was less than the 0.0004"
- 0.0007" thickness required. We can all electroplate and test measure to that standard can't we. Look at bottom of P3 for a few other cases
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here's a good one and fairly recent at that. The engine burst during a ground run, just like we would do. The shrapnel went as far as seriously damaging the airframe and the other engine. One piece (I assume it wasn't small) was found 2,500ft (1/2 mile) away. There were pictures on the web not long after but they all seem to have been withdrawn. I did send a copy to a few NG contributors.
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is only a brief description but it's another uncontained burst because "The pre-1979 3rd stage stator assembly in the right engine did not have the latest manufacture welding process/inspection and failed causing the uncontained turbine failure" These updates are notified to the airline users by the manufacturers. We would never get to hear of them.
These cases are rare compare to the total but they are in the profesional sector. Components on these engines are lifed and service schedules are critical. Knowledge of the engines history is essential to maintain this service level and allow safe running. Amateurs finding GT's in a scrap yard, getting them to run and exhibiting them in public is a recipe for a serious accident. A piston engine running at a 300 or even 3000 rpm is minor compared to the energy in a GT rotor at their speeds. If a con rod lets go, it rarely gets out of the crankcase or, if it does, it doesn't go far. Who wants to catch a lump of GT rotor
1/2 mile away. A 3ft diameter flywheel at 600rpm is doing about 65mph at the rim. That's a fraction of a GT's peripheral speed. As energy is proportional to the square of the speed, 10 times speed = 100 times energy. Energy is the potential to do damage.
There are ways to secure these failures. I've seen engines on pulling tractors wrapped in Kevlar blankets to contain shrapnel. The exhaust blast is not to be underestimated. This needs assessing. Airports are routinely cleared of birds and debris to prevent them being drawn into engines. Rally fields are not so well managed. They're full of birds, litter, children, dogs and debris. Finally, the public are not allowed airside at airports for very good reasons. Our shows actively encourage spectators. That puts them in the danger zone and also puts our engines in their danger zone. Can you imagine some hooligan thinking it would be fun to toss something into the inlet of one of these?
I'm sorry (really I am because I love engines), but the dangers are too great to allow uncontrolled running of these engines. Control to professional levels is the only answer but that would almost certainly price them out of our reach.
Axial compressors yes, but radial-flow compressors are less fussy. If it's an engine designed from scratch as an APU, then it may be a much wider useful range than this (at the loss of peak efficiency).
I also wonder if we need to ban some high-reving motorbikes. I've a friend who's bike can out-rev both of his turbines
That's interesting, I too used to ground run CF6 80A's on the 767. ISTR having to load the aircraft up with a minimum of (guessing) 20 tons of fuel, this was just to bring its weight up to a certain minimum so it wouldn't slide forward, wheels locked, over the chocks. The 80A's were babies compared to the C2 engines. I have to say that the CF-6 was a much nicer engine, from an engineering point of view, compared to the RB211. (535-E4)
Quite an interesting perspective there, mate. I've never been asked to leave an engine show because a hot air engine didn't fit in with the theme of the event. Do you think that the organizers are just being polite, but they are really laughing at me behing my back? How embarrassing!
If there are an uk.rec.engines.stationary members who secretly collect hot air engines, but are too embarrassed to bring them out to an English rally, mark your calendars for April 20-22 to be in Tulare, California.
Californian collectors, who don't have such a strict interpretation of what constitutes a stationary engine, will be hosting a multinational meeting of hot air enthusiasts. It's expected that we will have one of the finest collections of hot air engines ever assembled.
Well, I'm glad I posted on this subject. As I expected, there are those present that have considerable knowledge on the subject. Having read the replies & looked at the NTSB reports etc, I am now pretty well convinced that gas turbines are not the thing to have next to one in an engine line up.
Reluctantly, I can see the common sense of the principal concern that the likelihood of finding a GT that is within its hours and fit for running are few and far between. Most will have sat outdoors or in damp corners of hangers for years and corrosion is not an asset at high RPM!
I suppose the clinching argument is that whilst a piston engine might blow up if overstressed, the bits tend to stay inside as there is only a small centrifugal component. Not so with GT's.
Pity, I really quite fancied a Solent .................
But Kim, If you start running your turbines under the rated speed, you'll look like a bunch of silly Yanks out there in the rally field.
Engines running 30 seconds between firing... beautiful large Crossley engines running below 60 r.p.m.'s...
Where will the madness stop? Crankshafts snapping right and left, flywheels literally flying all over the place! Spectators flattened like Marmite filled pizza dough!
Go for it, with a bit of caution and common sense you'll be unlikely to have a serious problem. Better off away from the public really - like the corner of a farm yard perhaps?
Peter Grieve who runs the Merlin - and now a Griffon too - owns an engineering factory & is much better placed than most of us to ensure his handiwork stays in one piece. The Merlin is actually built from a WW2 crash recovery with a second hand crankcase fitted in place of the one that bit the dust & wiped off the reduction box.
He's rebuilding a Welland too ..........
I suspect that his PLI cover at the factory has been extended to cover his rallying activities. He seems to me to be a man that would not leave such things to chance.
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