jet engine servicability for ground runs ?

There’s a series of photos on the web somewhere of a Boeing 767 which has a turbine disk failure. The whole disk ejected complete from the engine, through the casing, through the FUSELAGE and into the engine on the OPPOSITE side!

Treat all jet engines with caution. Perhaps a few dry runs would be advisable after as thorough inspection as you can manage. Above all, FOLLOW THE MAINTENANCE MANUAL and pilots notes.

Having seen the results of XL232 shedding a disc I can only agree whole heartedly.

There’s a series of photos on the web somewhere of a Boeing 767 which has a turbine disk failure. The whole disk ejected complete from the engine, through the casing, through the FUSELAGE and into the engine on the OPPOSITE side!

Treat all jet engines with caution. Perhaps a few dry runs would be advisable after as thorough inspection as you can manage. Above all, FOLLOW THE MAINTENANCE MANUAL and pilots notes.

Wasnt there also a DC-10 that spat out the tail mounted engine’s fan stage?

took off most of the vertical tail if i remember correctly

There’s a series of photos on the web somewhere of a Boeing 767 which has a turbine disk failure. The whole disk ejected complete from the engine, through the casing, through the FUSELAGE and into the engine on the OPPOSITE side!

Treat all jet engines with caution. Perhaps a few dry runs would be advisable after as thorough inspection as you can manage. Above all, FOLLOW THE MAINTENANCE MANUAL and pilots notes.

Jet engines are certainly not designed to contain a catastrophic failure, certainly not the ones of museum vintage. Once a blade lets go in the early compressor stages, or even turbine stages, there is an enormous likelyhood of the blades penetrating the casing, and this has happened countless times, and has caused many fatalities. I myself have seen several incidents of catastrophic engine failure during my time as an aircraft Propulsion engineer, and in a fair proportion of these, there has been evidence of casing puncture, or actual blade loss through the casing.

Unless you have some idea of the history of the engine, I wouldn’t even begin to think about trying to run it up. There are so many variables, and so many dangers associated with it, that it’s not worth the risk IMHO.

Flipflopman

Rich & Max,

Bac 1-11 that suffered compressor failure:eek:

OUCH ,That looks expensive, :diablo:

Rich & Max,

Bac 1-11 that suffered compressor failure:eek:

I am very familiar with those rear bearing oil charges! 1/5th of a pint each I belive, which is 5 strokes of our little priming unit each.

Good man some people either don’t know or simply don’t bother

We are also very “temperature aware” and watch the EGT like hawks on every start. To be honest, I don’t belive you can ever considder running any old engine, of any type as totaly safe, there will always be an element of “calculated risk” involved. The main thing is to keep those risks as low as is absolutly possible.

I couldn’t agree more too many people get hold of an engine and go wild.

I keep a very detailed log of all our running time, including timing the rundown of the engine from H.P. **** closure on each run. This gives a good indication of the bearing states and any friction appearing in the engine.
Our group also consists of a good cross section of very expirienced and qualified engineers, as well as the usual weekend amatures, and we all talk and listen to each other, remember, no one knows it all, and you never stop learning.

A fantastic lesson in how to ground run a living breathing engine:)

If you want to do it on a smaller scale you could build your own basic turbojet from a turbocharger, as a turbocharger is basically a centrifugal jet engine by design, it lacks only the combustor section.

I have built a few such TJ’s now and they make for great fun, they also make plenty of noise and sound like the real thing, one engine i have made is fitted with a crude afterburner and mounted onto a kart frame, quite an exhilirating ride!

Ritch/max,don`t forget to run at 60+-1% and allow the JPT to fall and stabilise before closing the H-P c&*k;rundown should be 1min+.

Hi DeHavEng
Thanks for the coments, I am very familiar with those rear bearing oil charges! 1/5th of a pint each I belive, which is 5 strokes of our little priming unit each. We are also very “temperature aware” and watch the EGT like hawks on every start. To be honest, I don’t belive you can ever considder running any old engine, of any type as totaly safe, there will always be an element of “calculated risk” involved. The main thing is to keep those risks as low as is absolutly possible.
We are also very lucky, having a vast open space in which to opperate, I here stories of people running up engines in there garage, or driveway, they must be mental, give me half a mile of open sace any day!
We also realise that running our engine is not an indefinate option, so we enjoy it while we can.
I keep a very detailed log of all our running time, including timing the rundown of the engine from H.P. **** closure on each run. This gives a good indication of the bearing states and any friction appearing in the engine.
Our group also consists of a good cross section of very expirienced and qualified engineers, as well as the usual weekend amatures, and we all talk and listen to each other, remember, no one knows it all, and you never stop learning.

To quote Mr H Simpson….D’oh:D

My Friend Owns WW453 with a Alvis Leonedies Radial Engine, as fitted to all Provost T.1
thanks for your advice though, if i ever get a JP, then i will take your advice,
😀

The viper engine was designed as a ‘throw away’ E.C.U. if you friend has the engine log cards i suggest you check them throughly and find out how much if any life the engine has left. If it hasn’t any life left i wouldn’t even think about turning it over, catastrophic blade failure at high speed…not pleasant. if there is still life in the old girl a through inspection will normally suffice, just remember to prime the rear bearings before a run if the engine has been idle for more than 14days or you’ll trash the unit.

My Friend Owns WW453 with a Alvis Leonedies Radial Engine, as fitted to all Provost T.1
thanks for your advice though, if i ever get a JP, then i will take your advice,
😀

The viper engine was designed as a ‘throw away’ E.C.U. if you friend has the engine log cards i suggest you check them throughly and find out how much if any life the engine has left. If it hasn’t any life left i wouldn’t even think about turning it over, catastrophic blade failure at high speed…not pleasant. if there is still life in the old girl a through inspection will normally suffice, just remember to prime the rear bearings before a run if the engine has been idle for more than 14days or you’ll trash the unit.

Hi

I own a taxiable Jet provost T Mk.3A. fitted with a Bristol Siddley (not Rolls Royce!) Viper 102.
look for corrosion, it’s the castings that ofted suffer the most, so have a very good look, take a very powerfull light and look as deep into the engine as you can from both ends.

Rotate (watch your fingers) the compressor blades, they will always clatter around a lot at low speeds and temperature, so ignore that, you are looking for signs of rubbing between the casings and the rotating shafts. Check visualy all the blades you can see for signs of chipping, cracks, distortion and over heating, all can be a serious problem. If all seems well than thats a good start, but you won’t know for sure how good it is till you try to run it, at that stage, you are looking for metal in the filters, check any magnetic chip detectors if fitted and check for good oil pressure and temperatures in the specified range. Be very vigilant checking the condition of oil and fuel lines, they are probably the biggest fire risk you will have.

I am personaly of the view that a gas turbine is probably safer to run than a vintage reciprocating engine. It is VERY rare for a turbine to let go, but if it did, the engine is designed to hold it all in, and it is even rarer for anything to escape the cowling. I have seen a R.R. Tyne that lost a turbine and did a lot of damage to a Merchantman many years ago, but I think thats about it in over 34 years around aircraft, both proffesionaly and as a hobby. But I don’t even want to imagine the damage a runnaway prop could do, or a blade letting go due to either corrosion or unseed damage, and I certainly would’t want to be sat in the aircraft in either case, a runnaway prop is excitment you can do without, and an incomplete prop will tear the engine out of the airframe, and vibrate every tooth out of your head at the same time!!!!!!

Most of all remember, these are not toys, they are potentialy very dangerous in the wrong hands. Get qualified help, learn how to maintain and opperate the engine propperly, never cut corners, never modify anything, and follow strict safety rules, there is a very good reason that both the military and civil organisations do thing the way they do, and that way, you will live long enough to enjoy your investment.

If you ever want to get the feel of how it can be done, arrange to pop over to Bruntingthorpe one weekend when we are running an engine, we will give you a bit of a show with the Jet Provost, or ask 320PSI very nicely, and Andy will probably scare you to death with a Lightning!

Ritch a Max,
Many thanks for the Info,:)
I have been a Non Destructive testing engineer for over 10 years now, so if anyone can find corosion or problems i bet i can, all be it my main line of work is Radiography and Dye penatrant inspection, I am Qaulified to PCN Level 2

I however Do Not hold Aviation tickets , I only have tickets for welds etc,
if i can ever be of help, i would be keen to do so, 😀

one thing i wanted to do years ago was to fit a cockpit And engine on a fixed and properly Built trailor, ie a Vampire etc, or even just the engine to run up,
howevor, if i ever managed to get a complete airframe, (maybe a gang of us)
i would want it to ground run (safely) at least
Tops on my wish list would be a Mig 17, Meteor, Vampire, etc etc,
but i will just see what comes along one day. and the chance of a Mig are very few and far between, although i imagine there are still many over eastern europe,

Hi

I own a taxiable Jet provost T Mk.3A. fitted with a Bristol Siddley (not Rolls Royce!) Viper 102.
look for corrosion, it’s the castings that ofted suffer the most, so have a very good look, take a very powerfull light and look as deep into the engine as you can from both ends.

Rotate (watch your fingers) the compressor blades, they will always clatter around a lot at low speeds and temperature, so ignore that, you are looking for signs of rubbing between the casings and the rotating shafts. Check visualy all the blades you can see for signs of chipping, cracks, distortion and over heating, all can be a serious problem. If all seems well than thats a good start, but you won’t know for sure how good it is till you try to run it, at that stage, you are looking for metal in the filters, check any magnetic chip detectors if fitted and check for good oil pressure and temperatures in the specified range. Be very vigilant checking the condition of oil and fuel lines, they are probably the biggest fire risk you will have.

I am personaly of the view that a gas turbine is probably safer to run than a vintage reciprocating engine. It is VERY rare for a turbine to let go, but if it did, the engine is designed to hold it all in, and it is even rarer for anything to escape the cowling. I have seen a R.R. Tyne that lost a turbine and did a lot of damage to a Merchantman many years ago, but I think thats about it in over 34 years around aircraft, both proffesionaly and as a hobby. But I don’t even want to imagine the damage a runnaway prop could do, or a blade letting go due to either corrosion or unseed damage, and I certainly would’t want to be sat in the aircraft in either case, a runnaway prop is excitment you can do without, and an incomplete prop will tear the engine out of the airframe, and vibrate every tooth out of your head at the same time!!!!!!

Most of all remember, these are not toys, they are potentialy very dangerous in the wrong hands. Get qualified help, learn how to maintain and opperate the engine propperly, never cut corners, never modify anything, and follow strict safety rules, there is a very good reason that both the military and civil organisations do thing the way they do, and that way, you will live long enough to enjoy your investment.

If you ever want to get the feel of how it can be done, arrange to pop over to Bruntingthorpe one weekend when we are running an engine, we will give you a bit of a show with the Jet Provost, or ask 320PSI very nicely, and Andy will probably scare you to death with a Lightning!