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-   -   Bent airframes (https://www.pprune.org/military-aviation/569210-bent-airframes.html)

morrisman68 15th Oct 2015 07:59

Bent airframes
 
Apologies from a Newbie arm-chair enthusiast.

My brother flew, among other things, the Vickers Valiant and told me once that one of them always flew oddly, the airframe having been bent during some energetic manoeuvring to rid it of a 'weapon', though whether a shape or a live one during trials I never did sort out.

Can anyone clarify, please? Was/is it commonplace for airframes to have 'personalities' in this way?

Many thanks, in advance!

peppermint_jam 15th Oct 2015 08:35

From an engineers point of view, I would agree with this to a certain extent. Tornado GR1/4 ZA607 caused us much heartache over about a 2 year period with a horrible main computer fault. I seem to remember reading somewhere that Avro Vulcan XL444 (lovingly refered to as trembling whore!) was a horrible aircraft for the Engineers too.

[email protected] 15th Oct 2015 08:38

If you have ever seen a main rotor gearbox being put (manfully inserted) into a Sea King, you would know that no 2 airframes are identical:ok:

ian16th 15th Oct 2015 08:39

Not a bent air-frame, but in the early 60's 13 Sqdn at Akrotiri had a Canberra PR9 that flew slightly crabwise.

The Green Satin Doppler radar aerial was adjusted a degree or so, to correct this apparent navigation error.

Danny42C 15th Oct 2015 08:44

morrisman68,

Welcome into the great Brotherhood of PPRuNe !

Not commonplace, although every aircraft varies slightly, and there are known "rogues", but not so many now as in earlier years.

Was a story (for which I cannot vouch) that a Varsity was once "snagged" for strange trim problems.

Investigation revealed that the fin/rudder assembly was several degrees off vertical, more digging disclosed that it had been (illicitly) barrel-rolled by some miscreant who had kept quiet about it.

Danny42C.

Jackonicko 15th Oct 2015 08:58

Many years ago, I was writing an article about what it was like to fly the Hawker Fury. In doing so, I got to meet and interview a host of really lovely old gentlemen who had, in their youth, flown the aircraft.

One of them was Air Chief Marshal Sir Theodore Neuman 'Teddy' McEvoy KCB CBE, who wrote a short piece for us about the handling quirks of one particular Fury, which he described as a rogue.

The problem obviously goes back to the dawn of aviation!

Bengo 15th Oct 2015 09:17

There was a whole chunk in the Naval Aircraft Maintenance Manual (NAMMS) on what to do with a rogue aircraft, how to get one certified as such and how to get rid of it.

Then there was XV227- one of the pre-production Lynx HAS Mk1's- It was near impossible to get it avionic systems serviceable simultaneously and any correspondence between the topic 10 wiring diagrams and the actual aircraft was apparently a coincidence. I think it was eventually 'sold' to Pakistan. XV699 was the complete opposite- always serviceable.

N

John Eacott 15th Oct 2015 09:33


Originally Posted by Bengo (Post 9148351)
XV699 was the complete opposite- always serviceable.

N

I guess we have differing ideas of what is considered "always serviceable" ;)

http://www.eacott.com.au/gallery/d/1...am+overall.jpg

Yes, XV699 as 051 on 824NAS :p

Arkroyal 15th Oct 2015 10:01


13 Sqdn at Akrotiri had a Canberra PR9 that flew slightly crabwise.
:D :D

Thanks Ian16th

We had a very bent F27 on Channex which was a tiring night's work

morrisman68 15th Oct 2015 10:21

Thank you, so far!
 
Thank you, gentlemen, for reminiscences.

I often wondered whether this died out with the demise of hand-built and fitted airframes, though I suppose a determined airframe driver could bend anything, FBW permitting! And even then, we wonders...

Pontius Navigator 15th Oct 2015 11:24

Danny may recall that in addition to George, some aircraft had Gremlins.

There was the odd bent Vulcan around. One was overstressed by OC Bomber Wing when showing off on departure from Tehran. He didn't report the overstress and it was only discovered when an airman tripped on the wing ripple. He had at first thought the air brakes were out.

ShyTorque 15th Oct 2015 11:34

230 Sqn RAF had Puma HC1, XW222. From my time in the late 70s & early 80s it was known as "Trembling two", because it vibrated differently to all the others. I understand this airframe hasn't been upgraded/remanufactured into HC2 spec.

Maybe they never did cure it.

camelspyyder 15th Oct 2015 11:42


Then there was XV227- one of the pre-production Lynx HAS Mk1's
I knew that particular Nimrod was a rogue - now I find out it was a disguised Lynx:)



I have flown a C152 made from the best bits of 2 crashed ones. That was more "interesting" to fly than the others at the club.

NutLoose 15th Oct 2015 11:48

There was a rogue Wellington bomber during the war that was pulled off ops due to its tendency to fly around in circles, after intensive investigation they found a section of geodetric was missing from a stabiliser resulting in it flexing up and causing the problems.

I know of a lowly Cessna 152 that would yaw badly in flight, but cure itself at lower speeds and it took ages to find out the reason, it had the later wing mounted landing lights and at cruise the perspex leading edge cover was vibrating across and opening the internal wing up to the airflow, as it decreased speed it vibrated shut and was like that on the ground. Took the poor engineer ages to find it, and he only did when after one flight it didn't fully shut.

..

bluetail 15th Oct 2015 12:14

Nimrod MR2 XV251 was a known bent airframe, it needed a couple of degrees of rudder trim on to make it fly straight, it was banned from doing flying displays and in the front of its F700 had a statement as such.

RFCC 15th Oct 2015 12:28

At Honington a Buccaneer returned from the range sans Underwing Tanks, Flaps, Pitot tube, CBLs and various other bits and pieces. As part of the rectification we carried out a symmetry check in the hangar - spot on, did it again - same result!

However, the Hawker Siddley rep produced documents that has demonstrated that it had previously been known as a rogue aircraft - bent. It was ex-Navy and apparently swung to port on take-off.

Our enthusiastic pilot had straightened it for us.

Arclite01 15th Oct 2015 12:41

I flew a Viking that had a habit of dropping a wing at the stall (to the left), if you flew it slow it would always drop that wing, despite reporting it several times nothing could be found including after a geometry check. Still reported as No Fault Found !!!

Even odder was if it got chilly and we got condensation on the parked aircraft, that particular Viking would always have the port wing with condensation on it well before any of the others !! (cant remember the tail number).

I never enjoyed flying that one when I appeared on the rota for it..............


Arc

26er 15th Oct 2015 13:19

1955, 34 Squadron, Tangmere. We had a Meteor F8 WF742 which was very twisted and no amount of twitching could straighten it. Eventually all the trim tabs were set to zero and I offered to fly it to the MU at Aston Down. As I accelerated down the runway the left wing began to go down and once airborne I was unable to fly wings level above 180 knots. The landing was unusual. God knows what happened to it though it turned out that a mate was the unit test pilot there and he was not grateful for my gift.

ShyTorque 15th Oct 2015 13:29

Part way through my RAF flying scholarship, back in the dark ages, the civvy flying school received a C150 which wouldn't fly straight and in balance at the same time after a post-accident rebuild. It always dropped the left wing at the stall.

It was allocated to me and my instructor for a check ride; I had to spin it. From a normal entry it entered the spin very rapidly, flicked then settled and spun inverted, whereupon the engine promptly stopped. My instructor looked very surprised and asked me how I intended to recover. I said I would try easing back on the yoke after full opposite rudder, he nodded. It came out of the spin very quickly and the engine restarted itself as I raised the nose. The instructor abandoned the flight and the aircraft was taken off the flying programme. It was later found to have the wings rigged at different angles!

camlobe 15th Oct 2015 14:01

WL747 was an interesting airframe. One particular occasion required an aircraft as a backdrop for an event. The new BWENGO (Baby Wraf Eng O) carefully measured and marked two rectangles on the hangar floor, equidistant from the centre line.

"Do you want the aircraft on the centreline, or do you want the wheels in your nice little boxes?" Asks I. High pitched childish tirade as a response, so I suggested I would park the old grey lady with the wheels inside her little boxes. More high pitched childish noises because the aircraft was obviously not straight on the centre line. Her little mind could not accept such an aircraft could possible be bent, and went off to whine at SENGO. When they both returned, I had repositioned the aircraft centered along the line. SENGO took little WRAF away and gave her a good talking too, and explained that, yes, the RAF still operate aircraft that may well be slightly out of true, and she should accept the fact.

The main wheels were around two inches offset from her boxes.

Camlobe

P. S. Rumour has it that she latched onto a Bucc mate. Felt sorry for him.


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