Basic JET start-up question

Great to see a post with a lot of laughs!

Bri :D:D:D:D

Re Another Funky Avpin Start

I should add to my post above that I think it may have involved 23 Sqn

Another funky Avpin start

Can anyone substantiate the story of the 4? Lightnings staging through Diyarbakir in the late 60’s who had to resort to some very lateral thinking. As I recall they were on their way to Singapore and the stop at Diyarbakir was without groundcrew or any spare Avpin. When they came to start the next morning all the aircraft suffered wee-phutts which caused considerable misgivings. For you non-Lightning members a wee-phutt was a very common occurrence and was when the Avpin failed to light after the purging sequence; the ‘wee’ referring to the sound of the purging pump and the ‘phutt’ the sound of the Avpin failing to ignite. The Lightning Avpin tank held enough for 6 starts and now they had used 3, 2 at base and the one that they had just used, and they needed 2 more to get started. Rather than all try again and risk wasting more Avpin they tried another start with 2 of the aircraft but they failed again. Although these start failures were not unusual, 6 on the trot on 4 different aircraft was unprecedented so they decided to phone home to try and establish the common factor. The engineers at Leuchars couldn’t help but suggested that they should contact BAE at Warton. The expert at Warton quickly established that their problem was their location – Diyarbakir is 2200′ AMSL – and that the problem was therefore that there was insufficient head of atmospheric pressure for the Avpin plenum chamber to charge properly and that, somehow, they would have to overcome this problem. It was at this stage that the lateral thinking came in. The pilots came up with the suggestion of using a balloon to provide the required pressure but, of course, no balloons but what, unsurprisingly, they did have was the ubiquitous packets of three. So, the condoms were franged and put over the necks of the Avpin header tanks, the blue touchpaper was duly metaphorically lit and spectacular success. The unexpected bonus of this episode was that WIWOLs, thereafter, had the perfect excuse for their partners/wives as to why they were taking condoms on detachment!
It’s a lovely story and I have heard it several times but is it true or even nearly so? I would love to think so. I also cherish the image of a row of Lightnings with erect condoms attached to their header tanks in the spine behind the cockpit. The Turkish groundcrew must have watched with incredulity.

I like that one, it appeals to my warped sense of humour. The French have always considered the British crazy as far as I know so he probably thought that was just a crew ritual.

avpin starts

My favourite story of using Avpin involves the Canberra PR.9….yes she used avpin too. When transitting through airfields that were not used to the PR.9 it was common practice for the Nav to stay outside the aircraft on start-up in case of an avpin malfunction or wet start….i.e. no light up.
It was in 1973 and we were staging back to Wyton from Akrotiri. With the standard westerly jetstream across the Med we needed to refuel en-route and as Malta was closed to us at the time we used Istes, the French equivalent of Boscombe Down. Sure enough on trying to start the port engine we had a wet start. The method was to wait for 30 seconds or so and then use a piece of kitchen roll or something similar to wipe away the excess avpin from the drain hole to reduce the risk of that igniting on the second start. The other thing was to hit the leading edge of the wing, between the engine and the fuselage which was where the avpin tank was, to get rid of any air bubbles. I went to a French ground crewman who was watching this performance and borrowed a large monkey wrench from him. Using this I went and applied a few good thumps to the leading edge, then bingo she started beautifully. Surprise surprise the starboard had a wet start also and the pantomine performance was repeated before that too lit up.
A rather perplexed Frenchman was given back his monkey wrench before I climbed into the nose and we departed. I often wonder at his subsequent conversations on how the mad Anglais start their engines.

JUMP START A JET

Reputedly, in one of the India/Pakistan wars an Indian Gnat landed out of fuel on a Pakistan Air Force forward strip. After refuelling it, the PAF started the Gnat by pointing the aft end of a Sabre at one intake and the PAF pilot hit the relight button as the Gnat’s engine would up. All got a bit warm but seemingly it worked. The Gnat was certainly at PAF Peshawar in 1970/71.

I seem to recall whilst on detachment at RAF Valley 2 RAF F4J’s using the buddy system to start up after being left behind whilst being repaired.
They used to use a different kind of air starter unit instead of the ordinary Palouste. the new kind was the size of a small caravan, but had gone back with the rest of the squadron.
The groundcrew borrowed our palouste (on the rare occasion that it was serviceable after spitting blades out of the exhaust!) to get the engines spinning, and the other phantom provided the extra bit of oomph to get the engines to fire up.

The F4J’s used what was called direct air impingement starting. The hot air was blown directly over the turbine, winding the engine up to speed. There was no actual startmotor. It used a large volume of air which is alright if you have the USS Enterprise parked somewhere handy.

Never heard of anybody ‘playing’ with avpin,although no doubt somebody has been dumb enough at some stage.
There was a story at Brawdy that some genius decided to start a ‘yellow peril'(single cylinder diesel hand operated,walk with tractor) using avpin to prime the cylinder instead of using engine oil and apparently blowing the head off the damn thing.There was a suitable sized patch in the hangar roof supposedly caused by the cylinder head passing through it…might be true,anybody confirm ??
The nasty thing about avpin is that an extinguisher would not douse flames because it is a monofuel and does not need oxygen to burn.

cheers baz

Avpin sounds even nastier than det chord, something us pongoes had a healthy respect for if we had any sense. It was certainly not something to mess about with as it has a burn rate of about 8000 m/s. If you care to work it out that equates to about 18500 mph, or put another way, around the world in under 2 hours. How true it is I’ve no idea but I did hear tell of a bunch of Royal Engineers playing football with a ball of it and when someone kicked it it exploded removing their foot in the process. I suppose, like a squash ball, it gets hot if you keep knocking it around and it must have got hot enough to self ignite – if the story is true.

I can recall a story told by one of my instructors who was a sooty on Frightnings. Said sooty was conducting a ground run with another guy. Start up was fine, run up to full burner, guy on the ground starts waving franticly and pointing, said sooty looks behind him to see the entire spine on fire, swift exit from aircraft followed. Turned out avpin had leaked over both engines, the intial detonation ruptured the fuel lines. Needless to say the Frightning was a write off.

Avpin

Did many Avpin starts on mk9 Hunters at Ksar.one day we were towing a drum of Avpin back from stores in an Aden Gun trolley when we were flagged down by another driver”ere mate theres sparks coming from your load!”What had happened was the gun trolley hydraulic arm leaked and the assembly had lowered causing the Avpin drum to contact the road!The ridges on the 45 gallon drum where very shiny in places!If it had ignited ,well ,I and others wouldnt be around!!

Sorry for such a lamens question, But when starting a “historic” jet, what is the role of the wheeled generator type thing that the crew attach to the aircraft. Is it just literally a generator to spin the engines up :confused:

Hi,

The ‘wheeled generator’ we use to start the Lightning is in fact a 24v Trolley Acc, basicly two 12v lorry batteries connected together, this gives the aircraft ground power, a Hochin ground set is the thing to use really which gives both AC and DC power and has plenty of ‘umph’ (a big engine with a large geni and alternator basicly).

We get by just fine with our Acc which is very low maintance

Once the Acc is connected, the aircraft can be readied to start up, this on a Lightning invloves a complicated series of events thats abit to detailed to go into here, but basiclly the ‘shot’ of avpin is used to create a fast ‘blast’ of gas into a primary turbine which turns a reduction and winds the engine up to idle RPM of 34% with in 9 seconds, at this stage with pumps on and HP **** (throttle) open the engine should become self sertaining.

There is alot more to it than that, but thats the basic’s

Come to Brunty sometime and I can show you exactly how is all works, its much easier to explain face to face 😉

Cheers

Now I am not sure if I got my facts right here, but I seem to remember ex-Buccaneer display pilot, Glenn Mason, mention a time when they tried to fire up XZ431 (I think) with a Hawk after all the ground equipment had gone back to base, I will try and firm this up with him.

I have a feeling it was at the end of Cranfield Dreamflight airshow in 1992.

[QUOTE=lothar;1265172]

2 RAF F4J’s using the buddy system to start up /QUOTE]

From what I recall, the buddy start between F4Js involved connecting an air pipe from the compressor section of the donor aircraft that fed into the Palouste coupling on the receiver. It did not involve using the jet exhaust directed at the receivers intake especially with the F4 where the intakes were significantly higher than the jetpipe exhausts and these exhausts were angled down quite significantly. And you are quite right the normal F4J Palouste was indeed the size of a small caravan!

AAAh i did think it was a little odd! perhaps they just borrowed the hose from our palouste to cobble one up to fit between the aircraft.

[QUOTE=bloodnok;1265153] 2 RAF F4J’s using the buddy system to start up /QUOTE]

From what I recall, the buddy start between F4Js involved connecting an air pipe from the compressor section of the donor aircraft that fed into the Palouste coupling on the receiver. It did not involve using the jet exhaust directed at the receivers intake especially with the F4 where the intakes were significantly higher than the jetpipe exhausts and these exhausts were angled down quite significantly. And you are quite right the normal F4J Palouste was indeed the size of a small caravan!

I seem to recall whilst on detachment at RAF Valley 2 RAF F4J’s using the buddy system to start up after being left behind whilst being repaired.
They used to use a different kind of air starter unit instead of the ordinary Palouste. the new kind was the size of a small caravan, but had gone back with the rest of the squadron.
The groundcrew borrowed our palouste (on the rare occasion that it was serviceable after spitting blades out of the exhaust!) to get the engines spinning, and the other phantom provided the extra bit of oomph to get the engines to fire up.

If you think canberra/hunter cartridge starts were impressive, you should see a F-111 start up on its carts!
Compared to a hunter cartridge they were massive, about the size of a 5ltr tin of paint, and on occasion i’ve seen the airfield crash tenders scramble because they’ve thought the aircraft had gone up in a cloud of smoke!

Especially if it were a Javelin!!! I have heard the word “Run” used by ex-Jav ground crews on many occassion.

:D:D I remember the Javs at Wattisham when I was a cadet. You’d hear the bang of the cartridge and if they were lucky they’d be rewarded with that horrible whine the Sapphire had. It has to be one of the most horrible sounding engines I’ve heard though I’d love to see one on the display circuit. Having said that I don’t think many places would allow one to operate from their airfield as you’d be forever patching up holes in the boundary fences/hedges/whatever as Javs were notoriously good at break failures on landing.

I find that hard to believe. Avpin detonates at something like 7 Km per second, if you threw a bucket of avpin down the intake, there would be nothing left in short order, including the bloke with the fire cart, the bloke with the burning rag, the bloke with the bucket or anything within a hundred feet all around.

Like i said, ts only something id heard, i wouldnt have thought there would be too much truth to it

Buddy starts

That same “thrust” might have a somewhat detrimental effect on the surface finish etc of the aircraft behind….:diablo:
I have heard of prop aircraft being started using that kind of method, but that’s it……. :confused:

I have never heard of buddy starts being used by pure jet aircraft – too many difficulties:-
a. it would be almost impossible to direct the exhaust from the donor aircraft sufficiently accurately into the intake of the receiver.
b. to achieve a. the donor aircraft would need to be so close to the receiver that damage would inevitably ensue.
c. the receiver aircraft’s pilot would also have a few problems of his own.
d. I hesitate to think what TGT/JPT would result in the receiver aircraft.
Buddy starts are however used by turboprop aircraft and the C130 certainly had it as an SOP. It was comparatively easy to line up the wake from an
outboard engine to that of the receiver and there was little risk of damage due to hot exhausts. Does anybody know of any other aircraft where this was a recognised and approved option?

PS. I should add xf382 that XF382 appears in my logbook on more than one occasion.

I find that hard to believe. Avpin detonates at something like 7 Km per second, if you threw a bucket of avpin down the intake, there would be nothing left in short order, including the bloke with the fire cart, the bloke with the burning rag, the bloke with the bucket or anything within a hundred feet all around.

Yes exactly..in the late 70’s a few of us erks went in a 39 seater RAF bus to service some hawks and hunters which had weather diverted to Cardiff.Two jerrycans of avpin were wedged right at the back and all us ‘brave’ erks were huddled together right at the front.
Even though it was snowing heavily our driver ‘knew a shortcut’ in spite of our advice otherwise and we ended up at a vertical snow wall where the snowblow machine had given up :rolleyes:…quick reverse to farm entrance and back to main road 😀
the poor hunter boys had all sorts of problems to sort out but us 2 hawk boys went to a party 😀 happy days (until next morning anyway !!) rest of it a blur 😀

cheers baz

The most alarming Avpin starting story ive heard was for recalcitrant Hunters & Canberras.

walk up to intake of choice with bucket of Avpin and heave it down the intake, followed by second erk holding a long stick with a burning rag on the end sticking said burning end into the intake to light it!

i do recall that a third erk was usually on standby with a fire cart for when burning Avpin came pouring out the back!

I find that hard to believe. Avpin detonates at something like 7 Km per second, if you threw a bucket of avpin down the intake, there would be nothing left in short order, including the bloke with the fire cart, the bloke with the burning rag, the bloke with the bucket or anything within a hundred feet all around.