Any Borneo Whirlwind veterans here?
We used HF in Sabah on 230 Sqn. 4469 USB (?) The airwaves would resound with "Butcher Butcher Butcher, this is Baker Baker Baker". You were supposed to pass a position report whenever you left an LZ but you were very unlkely to get through. Quite often there would be heavy breakthrough from activity in Viet Nam. On one occasion some worthy was trying to pass a position report to Butcher and this American voice came up.
"GET OFF THIS GODDAMMNED FREQUENCY! DON'T YOU KNOW THERE IS A WAR ON?"
"Yes; actually I do. But we're winning ours."
For the benefit of India Four Two and the risk of boring a load of ex Whirwind bods to tears here goes.
The aircraft was probably around 10,000lbs, 2,200lbs overweight; but no difference in stresses compared with a tie down base.
The Saga of Stall Margin checks on the Gnome.
Those that fly helicopters powered by the GE T58/de.H/RR Gnome will know that it has a ten stage axial compressor with three stages of variable stator vanes. The angle of these vanes is changed by a fuel pressure powered actuator to suit the RPM of the engine. The faster the engine goes the more the vanes open up to improve compressor performance and as it slow down they are closed up so give the front stages a better bite at the air. There is a RPM point at which the actuator starts working as the revs rise and another point at a higher RPM where it starts working as the revs fall. They found that engines were stalling even though the actuators had closed correctly. This was put down to general corrosion and wear and tear. To over come this it was necessary to ensure that the engine would not stall during and at a certain level below the actuators operating range. This was called the Stall Margin.
It must have been a de Havilland problem because with all my knowledge of T58 operations they do not seem to suffer. It first arose at Tern Hill in the days when places like Sheffield and the Potteries were going full blast and the haze layer went up to 4,000 ft.. To ascertain how badly the compressor was eroded a procedure known as the Stall Margin Check was incorporated.
The aircraft was strapped down to a Tie Down base. The aircraft was started and as the pilot accelerated the engine the RPM at which the actuator commenced its travel was noted. The engine (and Rotor) was then accelerated to about 20,000 RPM and then slowly decelerated until the actuator stared closing again. This was your actuator range check. The Gnome had a built in electric fuel shut off valve tied in with the overspeed protection so this was jumped into a cable of which the other end had a box with a big button. This button would stop the engine; instantaneously. This would have been mounted before the runs started so the engine was shutdown using it as the check.
The engine was started again and accelerated to 20,000 RPM. Whilst the engine was kept at this level the guide vane operating lever would have a locking sleeve attached to it to prevent it being moved by the actuator. So now the engine was running with the vanes locked in the high speed position. The engine was now decelerated slowly; through the two actuator operating RPMs and then below. It would then reach a point where the engine would stall. The Chief Tech in the left hand seat would press his stop button the and pilot would drop the lever and pull off the HP cock as a backup. Should both of them be too slow the engine RPM would disappear left and the PTIT gauge would disappear right. This was not unknown.
IIRC a minimum of 1,400 RPM was required below the RPM at which the actuator started to move. Any thing from Zero to 800 RPM was common.
As a result of doing innumerable checks my confidence in the Gnome overspeed protection was not very high which is probably why it was isolated on the aircraft. I had several occasions where the electrics didn’t work the second time but though practice and knowing what was going on I saved the engine. When the engine went THUMP a very switched on Chief Tech Heatherington could stop the engine before the ‘U’ but other Chief Techs did not seem to fully realise what was going on. The practice of having a unofficial maintenance test pilot helped as he did all the tie downs and air tests. A Joe just pulled out of the crew room would have got away with it most times but if something had gone wrong, as was proven, you lost the engine.
"GET OFF THIS GODDAMMNED FREQUENCY! DON'T YOU KNOW THERE IS A WAR ON?"
"Yes; actually I do. But we're winning ours."
For the benefit of India Four Two and the risk of boring a load of ex Whirwind bods to tears here goes.
The aircraft was probably around 10,000lbs, 2,200lbs overweight; but no difference in stresses compared with a tie down base.
The Saga of Stall Margin checks on the Gnome.
Those that fly helicopters powered by the GE T58/de.H/RR Gnome will know that it has a ten stage axial compressor with three stages of variable stator vanes. The angle of these vanes is changed by a fuel pressure powered actuator to suit the RPM of the engine. The faster the engine goes the more the vanes open up to improve compressor performance and as it slow down they are closed up so give the front stages a better bite at the air. There is a RPM point at which the actuator starts working as the revs rise and another point at a higher RPM where it starts working as the revs fall. They found that engines were stalling even though the actuators had closed correctly. This was put down to general corrosion and wear and tear. To over come this it was necessary to ensure that the engine would not stall during and at a certain level below the actuators operating range. This was called the Stall Margin.
It must have been a de Havilland problem because with all my knowledge of T58 operations they do not seem to suffer. It first arose at Tern Hill in the days when places like Sheffield and the Potteries were going full blast and the haze layer went up to 4,000 ft.. To ascertain how badly the compressor was eroded a procedure known as the Stall Margin Check was incorporated.
The aircraft was strapped down to a Tie Down base. The aircraft was started and as the pilot accelerated the engine the RPM at which the actuator commenced its travel was noted. The engine (and Rotor) was then accelerated to about 20,000 RPM and then slowly decelerated until the actuator stared closing again. This was your actuator range check. The Gnome had a built in electric fuel shut off valve tied in with the overspeed protection so this was jumped into a cable of which the other end had a box with a big button. This button would stop the engine; instantaneously. This would have been mounted before the runs started so the engine was shutdown using it as the check.
The engine was started again and accelerated to 20,000 RPM. Whilst the engine was kept at this level the guide vane operating lever would have a locking sleeve attached to it to prevent it being moved by the actuator. So now the engine was running with the vanes locked in the high speed position. The engine was now decelerated slowly; through the two actuator operating RPMs and then below. It would then reach a point where the engine would stall. The Chief Tech in the left hand seat would press his stop button the and pilot would drop the lever and pull off the HP cock as a backup. Should both of them be too slow the engine RPM would disappear left and the PTIT gauge would disappear right. This was not unknown.
IIRC a minimum of 1,400 RPM was required below the RPM at which the actuator started to move. Any thing from Zero to 800 RPM was common.
As a result of doing innumerable checks my confidence in the Gnome overspeed protection was not very high which is probably why it was isolated on the aircraft. I had several occasions where the electrics didn’t work the second time but though practice and knowing what was going on I saved the engine. When the engine went THUMP a very switched on Chief Tech Heatherington could stop the engine before the ‘U’ but other Chief Techs did not seem to fully realise what was going on. The practice of having a unofficial maintenance test pilot helped as he did all the tie downs and air tests. A Joe just pulled out of the crew room would have got away with it most times but if something had gone wrong, as was proven, you lost the engine.
Last edited by Fareastdriver; 8th Aug 2012 at 14:43.
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Thank you F.E.D., you didn't bore me to tears - in fact I had forgotten the detail of almost all of that after 45 years, and it all came back! Your post surely is the definitive historical record of the stall margin checks on the Gnome.
It should be printed off and placed in the aircraft in the RAF Museum.
It should be printed off and placed in the aircraft in the RAF Museum.
Gentleman Aviator
Used to have a lot of "zero" stall margins on 78 Sqn Wessex in Sharjah - sand erosion being the problem there.
But at least we had two engines! (both Gnomes for the uninitiated)
But at least we had two engines! (both Gnomes for the uninitiated)
Fareastdriver,
Thanks very much. Most informative and fascinating. I had no idea about the variable stator vanes in the Gnome.
I have to say I'm glad I didn't know any of this information when I first became acquainted with the Whirlwind. I was sitting in a dinghy off Bridlington, while a Leconfield HAR 10 hovered over my head. I do remember thinking at the time 'I hope he doesn't have an engine failure right now!'
Thanks very much. Most informative and fascinating. I had no idea about the variable stator vanes in the Gnome.
I have to say I'm glad I didn't know any of this information when I first became acquainted with the Whirlwind. I was sitting in a dinghy off Bridlington, while a Leconfield HAR 10 hovered over my head. I do remember thinking at the time 'I hope he doesn't have an engine failure right now!'
Last edited by India Four Two; 26th May 2012 at 15:15.
I agree with Tiger Mate. The Whirlwind 4 and onwards had the cranked boom because of the rolling couple. The tailskid was also a lot stronger.
For those interested in the fate of various Whirlwinds I had previously posted the end of XR 478's flying career.
http://www.pprune.org/where-they-now...unky-lord.html
For those interested in the fate of various Whirlwinds I had previously posted the end of XR 478's flying career.
http://www.pprune.org/where-they-now...unky-lord.html
Last edited by Fareastdriver; 27th May 2012 at 09:21.
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Gents; your assistance both through these pages and direct has been awesome for which I thank you. I am making good progress with the painting but have hit a brick wall when it comes to inside the cabin of a Whirlwind. I want to depict an appropriately dressed crewman at the door with a hint of the inside detail (hence the white area in the door). Any pics of the same would be most welcome; I understand that a clear floor was the order of the day but need info on sound proofing or interior structure if the same as the Wessex.
Last edited by Tiger_mate; 29th May 2012 at 04:58.
sound proofing
Ha ha ha ha. There wasn't any. The cabin was clean; the only gesture towards flight safety was that the seat belts were left attached to the wall when the seats were removed. The only seat that I can remember was the three seater that went across the front of the cabin. Troops; if they wanted to strap had to sit on the floor. Most didn't bother. It was only late 1966 that we carried a crewman on every trip; before that he would stay at the base and act as Movements. Most of the time we could not afford to carry a crewman; there were too many troops to move.
He, or a couple of Gurkas would sit with there legs dangling over the sill. At that time a crewman would have a two piece flying helmet with a silver finish, and most would have scrounged an Australian light green flying suit Gurkas wore jungle hat, drab green kit and the famous green jungle boots.
I have a picture of a typical lift out of a DZ. It will, however, take me some time to find it.
Watch this space.
FED - the coupling for the variable stator actuator was (I believe) a pin through a fork-end (in simplistic terms). The significance was that on a Friday evening return to Tern Hill from Valley, one George K decided to make it a 'sporting arrival' - low, fast (for a WW!) run-in downwind, pull up for a torque turn and gently down to finish off the week. Unfortunately, and unknown to GK, the coupling pin had detached itself en-route and the application of collective at the appropriate moment produced a most eye-catching outpouring of flame and smoke and a subsequent relieved engagement with terra firma. 
Very spectacular and almost as exciting as the day we discovered that it was possible to install the WW tail rotor the wrong way round!!
Very spectacular and almost as exciting as the day we discovered that it was possible to install the WW tail rotor the wrong way round!!
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More Pics of Whirlwinds during confrontation on Key....
Tiger Mate:
More pictures of Whirlwinds and some of bases used, on Key Publishing "Historic Aviation" under the thread "Confrontation - know your enemy, was it Soekarno ?"
See: Confrontation - Know your enemy, was it Soekarno ? - Key Publishing Ltd Aviation Forums
The No. 1 enemy was considered by many of us who were on the things as "The Gnome".....
The pilot in the light green flying suit in dayglo XR456 looks very nuch like George Kelson to me, the inventor of a particular "Donkey" name for the horrible, round, "kind of" similar to, Luncheon meat sandwiches made by the cook at Nanga Gaat for our box lunches....
Best of luck with the painting.
DB - Ex-F/E Crewman 110 Sqdn.
More pictures of Whirlwinds and some of bases used, on Key Publishing "Historic Aviation" under the thread "Confrontation - know your enemy, was it Soekarno ?"
See: Confrontation - Know your enemy, was it Soekarno ? - Key Publishing Ltd Aviation Forums
The No. 1 enemy was considered by many of us who were on the things as "The Gnome".....
The pilot in the light green flying suit in dayglo XR456 looks very nuch like George Kelson to me, the inventor of a particular "Donkey" name for the horrible, round, "kind of" similar to, Luncheon meat sandwiches made by the cook at Nanga Gaat for our box lunches....
Best of luck with the painting.
DB - Ex-F/E Crewman 110 Sqdn.
Last edited by David Billings; 28th May 2012 at 07:15.
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Borneo Veterans
Very interesting subject. I was a crewman on 110/103 Squadrons at Labuan, with lots of time at Bario, before returning to UK and the F/E course (Hastings and C-130K) This was June 1964 to June 1965, does this tie in with anyone else? Flew with Chunky Lord several times.
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The Gnome engine stall was a bit more complicated than it seemed. Sometimes air got into the high pressure fuel system and ended up in the IGV actuator causing sluggish action and a stall if power increases were done in a hurry. Also interaction with the DH designed engine computor was another source of woe. As originally designed, if the engine suffered a stall, the governor sensed the T4 rise and shut the throttle to the minimum flow which would likely un-stall the engine. Unfortunately, by now the pilot seeing the loss of power would grab the manual throttle selector (if he had time) and wind up the power. If successful, he would then go home and snag the computor for a run down. The fix for the perceived computor rundown problem was to fit the selectable flight idle stop which prevented the N1 going below 19000 odd RPM in a rundown. Unfortunately this guaranteed an engine burn out (and I had two) in the event of a stall as the computor couldn't shut the throttle.
After RAF Whirlwind flying, I went to Leavesden just before they shut the plant and the team who used to do the computor work dug out their test set and tested a computor for an ex RAF Whirwind for us. They confirmed that large number of the /5 computors returned to the factory were actually fully serviceable. The problem was that the signalling circuits (N1,N2, T1,T4 and throttle valve angle) were all sensitive to damp, corroded terminals and poor connections leading to apparent computor problems. I had one where the T4 signal was intermittent. When it disconnected, the computor continued OK but when it re-connected, the computor sensed this as a rapid T4 rise and shut the throttle. That took two computor changes and a complete system diagnostic to work out.
A lot of the above experience only came to light right at the end of RAF Whirlwind flying and continuing into civil operation.
After RAF Whirlwind flying, I went to Leavesden just before they shut the plant and the team who used to do the computor work dug out their test set and tested a computor for an ex RAF Whirwind for us. They confirmed that large number of the /5 computors returned to the factory were actually fully serviceable. The problem was that the signalling circuits (N1,N2, T1,T4 and throttle valve angle) were all sensitive to damp, corroded terminals and poor connections leading to apparent computor problems. I had one where the T4 signal was intermittent. When it disconnected, the computor continued OK but when it re-connected, the computor sensed this as a rapid T4 rise and shut the throttle. That took two computor changes and a complete system diagnostic to work out.
A lot of the above experience only came to light right at the end of RAF Whirlwind flying and continuing into civil operation.
hit a brick wall when it comes to inside the cabin
Either way, it looks like it will be a fine painting when finished.
I have just seen the rope. On a roping trip the crewman will be by the door, looking forward as the aircraft is approaching the Roping Zone. The troops will still be sitting on the floor the other side of the cabin. A free air hover in Borneo will mean that a maximum of four troops will be in the back. The only people I ever roped in were SAS; Brit/Aus/NZ; so their faces would be blackened. You would only see a couple of them in the cabin in that view.
Gentleman Aviator
The significance was that on a Friday evening return to Tern Hill from Valley, one George K decided to make it a 'sporting arrival' - low, fast (for a WW!) run-in downwind, pull up for a torque turn and gently down to finish off the week.
I was a passenger down the back with the girly dentist and we'd just flown low level all the way back from Valley .....
.... as we slithered to a halt, ATC (in "sharp as a beachball" mode) asked what had happened. Don H replied "the bl
dy donk's crook" or similar, and the poor girls in the tower didn't know what he meant!Must have been late '69, early '70 .... I might work it out from logbook; as pax I wouldn't have logged the return, but I probably flew the TH-VY leg. Course mate in RHS for the VY-TH retired as a 4-star ........
And of course the engineers tried to blame the aircrew - who should have noticed the lack of locking wire/split pin/castellated nut/all of the above on the walkround!!
Edited to add: looks like 5th Feb 1970 in XP 341. That was a Thursday too so maybe it did happen twice
And the next day was solo EOLs in XP 355 .....
Last edited by teeteringhead; 30th May 2012 at 13:11.
"Mildly" Eccentric Stardriver
Teeteringhead, I'm glad you mentioned solo EOLs. There's another thread somewhere that seemed to suggest they were only flown dual. My logbook shows I flew thirty minutes solo EOLs in XD163 on 6th Oct '66. I was beginning to think age was twisting my memory.
Gentleman Aviator
Herod - they were flown solo until the Whirlwind went out of basic training at Shawbury in 1979. When the Gazelle began to be used for basic, student solo EOLs were binned - after much heated discussion on both sides.
I recall a number of us crowding into the tower at Ternhill to watch the very very last basic student solo EOLs - Tom T was the QHI and IIRC one of the I** M*********s (there are two!) was the stude.
In the discussions, I remember John G W (no hyphen!) - who was in favour - saying words to the effect:
I recall a number of us crowding into the tower at Ternhill to watch the very very last basic student solo EOLs - Tom T was the QHI and IIRC one of the I** M*********s (there are two!) was the stude.
In the discussions, I remember John G W (no hyphen!) - who was in favour - saying words to the effect:
I know the Americans wouldn't and the Israelis would - whose camp would you rather be in!
Teeteringhead - absolutely correct, of course!!
The joys of a memory which is receding rather faster than the hairline! Ah well, I did at least remember to get up today ... I think
PS - I'vejust been scanning some old slides from that era, a couple of which , at first glance, appeared to be a flock of birds. Once they were enlarged they were rather poor shots of a large 'formation' (same way, same day) of Sioux and Whirlwinds. Wracking the few remaining brain cells dredged up a faint memory of some sort of mass flypast celebrating some particular occasion but details are totally absent! Anyone remember this?
The joys of a memory which is receding rather faster than the hairline! Ah well, I did at least remember to get up today ... I think
PS - I'vejust been scanning some old slides from that era, a couple of which , at first glance, appeared to be a flock of birds. Once they were enlarged they were rather poor shots of a large 'formation' (same way, same day) of Sioux and Whirlwinds. Wracking the few remaining brain cells dredged up a faint memory of some sort of mass flypast celebrating some particular occasion but details are totally absent! Anyone remember this?
Last edited by Cornish Jack; 1st Jun 2012 at 21:29.
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The painting adventure is moving into camp. The layout will be based upon Nanga Gaat, but not a slave to reality. I am going to enlarge the maintenance shed and include another Whirlwind (with tropical nose) on the ground with some engineers. Any photos that would assist in this crusade would be welcome. A question: it appears that 40gall drumstock was the order of the day and the drums were burgundy with blue ends. Was that a particular fuel company colour scheme? ie one would expect Shell to be red and yellow, BP green and yellow etc etc
Painting the jungle makes you brain dead.
Painting the jungle makes you brain dead.