View Full Version : Canberra confusion

21st Jul 2013, 22:03
Here's a real head-scratcher...

As Canberra experts will know, the Canberra PR9 carried tips tanks (when required) on the original B2/6 wing tip, so they were slightly inboard of the extended PR9 wing tip.

However, WH973 appears to be the one exception to the rule:-


The aircraft started-off as a PR7 and was modified to PR9 configuration (retaining the original B2 nose). Serving with the RAE, it was employed on gust research and on a few photos, the tip tanks appear to be fitted on the actual tips of the extended PR9 wing. Some of my colleagues insist it's an optical illusion but I'm convinced that the tanks (pods actually, as they didn't carry fuel) are indeed attached to the extended wing tips.

Anyone know any other photos that prove/disprove this? And if they really are in this odd position, then why?

22nd Jul 2013, 17:01
I found the two images below on Google, although it's true to say that photos of PR9s with tanks/pods seem to be few and far between. I'm no type specialist, so you will have to decide if they are actually PR9s or not, but they are captioned as such in both instances.

No1 - PR9 with tanks/pods 'on' wing tip - similar to your photo:

No 2 - PR9 with tanks/pods well under wing tip:

Harley Quinn
22nd Jul 2013, 18:05
I found the two images below on Google, although it's true to say that photos of PR9s with tanks/pods seem to be few and far between. I'm no type specialist, so you will have to decide if they are actually PR9s or not, but they are captioned as such in both instances.

No1 - PR9 with tanks/pods 'on' wing tip - similar to your photo:

No 2 - PR9 with tanks/pods well under wing tip:

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Windy Militant
22nd Jul 2013, 18:09
Unfortunately the picture In my copy of " A short illustrated History of the RAE Bedford" by Arthur Pearcy is cropped so doesn't show the wing tips however it does say that WH793 participated in the HICAT programme in 1967 and was based at NASAs Ames research centre at Moffat Field.
A quick Goggle on clear air turbulence test bed has thrown up a whole load of flight sim and model pictures but only one actual image which is here and by the looks of it copy righted up to the ying yang so I've posted the link instead
Canberra PR Mk.7 WH793 Masirah 06101972 D12606 (http://www.aero-pics.co.uk/miscellany/Canberra%20PR%20Mk.7%20WH793%20Masirah%2006101972%20D12606.h tm)

It also shows zaps for project COLDCAT RAF Tengah, StormForm and Operations Rover 1967.

Harley Quinn
22nd Jul 2013, 18:09
TBH I can't see a difference that couldn't be explained by angle of view and shadow.

WH973 was written off twice following accidents

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Harley Quinn
22nd Jul 2013, 18:13
TBH I can't see a difference that couldn't be explained by angle of view and shadow.

WH973 was written off twice following accidents

Posted from PPRuNe.org App for Android

Posted from Pprune.org App for Android

Harley Quinn
22nd Jul 2013, 18:15
Of course if we were all talking about the same airframe (WH793) that would help!

Posted from PPRuNe.org App for Android [/quote]

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22nd Jul 2013, 18:25

Aircraft flown by the RAE were often unique, despite their apparent resemblance to front-line types.

Googling Canberra WH793 brings up quite a bit of relevant info, ie it was a HAPR.9 converted by Napier from a PR7 with the new proposed PR9 wing configuration, which first flew 8 July 1955.

The following link has a different image in the RAE Aero Flt Bedford livery with a better indication of the Tip Tank fit:

Topic: HAPR.9 WH793, this time at the end of the story - IPMS UK Canberra SIG (http://ipmscanberrasig.webs.com/apps/forums/topics/show/7721696-hapr-9-wh793-this-time-at-the-end-of-the-story)


22nd Jul 2013, 19:13
The above link/s highlight the problem! The chap who has carefully built the model firmly believes that the aircraft was re-winged with standard B2 wings, but only because he thinks it would have been ludicrous to have fitted the tanks in a non-standard position (I asked him about this).

Likewise, the flight simulator people have made the same assumption, probably because they've picked-up the same assertion off the internet. It becomes a sort of Chinese whisper and if we're not careful it will become fact, even though photographs clearly show it isn't fact at all.

However, examination of photographs clearly shows that the tanks are attached to the tips of a PR9 outer wing. There's no logical reason why the tanks (pods in this case) would be attached here, as they could have been attached on the standard PR9 position on the original B2 wing tip inboard. So there must have been a good reason why they were not.

Even Adrian Balch's magnificent book "Testing Colours" doesn't solve the mystery. Two lovely photos in there, but they only show the starboard tank (pod) attached to a wing tip, but no clarification as to what wing tip it is. But close examination of the shape and the navigation light suggests it's a PR9 wing.

So... this is where I came in. Logic suggests that the tanks should be fitted to a standard B2 outer wing but even on the above photo, you can see that it isn't a B2 outer wing, it's a PR9 wing.

It's a very odd machine!

22nd Jul 2013, 19:22
nacluv thanks for the photo links. That helps to explain what I'm getting at. The top machine is a PR9, the lower aircraft is also (technically) a PR9 although it's designated as an SC9 (it was a non-standard RAE machine). As you can see, the tip tanks are not actually on the wing tips, they're attached to the tip of the original B2 wing structure, just inboard. However WH973 has the same longer wings, but the tanks (they're actually equipment pods) are on the actual tips. This is the mystery - why would they be there?

22nd Jul 2013, 20:04
This is my first post, I've been trying to get to the bottom of this conundrum for some time, I am the person responsible for the model of WH793 on the link, my reasoning for the modified or should that be de modified wing tip is as follows.

This is the summery for the test flights carried out by WH793 in 1967 in the USA


In a number of flights in the stratosphere over mountainous terrain in

the western U.S.A., much valuable data was collected. Flights "are planned

on the basis of tropospheric lee wave forecasts and were usually made along

wind at heights from the tropopause to about 50000 ft over California and

Nevada. Mountain waves, deduced from an analysis of the temperature along

the flight track, were moderate or strong on four flights. Moderate or severe

turbulence and marked temperature changes were encountered on three flights.

The results give an insight into the severity of the stratospheric environment

and the meteorological conditions in which the severe disturbances occur.

My reasoning behind the standard wing tips on 793?
The extended wing span would serve no advantage in a gusty turbulent environment, indeed it would only amplify any airframe buffet and add to crew discomfort.
The PR.9 wing tip is not and was never intended to support any
weight, it is purely an increase in span. All the electrical wiring and fuel
goes to the same point as it dose on the standard PR.7 wing and any other
Canberra wing. The wing on the production PR.9's are basically that of the
B(I)8 but with the area increased. There would be no advantage in increasing the strength or re designing the tips on 793.
The wing tip of the Canberra is relatively easy to remove and the two types of wing tip and they are quite interchangeable.

I have closely studied photos of 793 from this time
and I can see no evidence of modifications to the tip tanks that would
indicate that they are fitted to anything other than the standard Canberra
wing tip. In order for the tanks to fit the PR.9 wing the tip tanks need a
fairing to modify the shape to the new wing profile.

I wouldn’t fancy flying through CAT with two hefty pods hanging off a relatively flimsy structure. The small increase in altitude gained from the extra span wouldn’t warrant the extra work involved in all the cost and effort in redesigning and beefing up the PR.9 wing tips, that for me is one of the biggest clues to the normal wing tips being re fitted, you wouldn’t go to all the trouble of ignoring a perfectly serviceable electrical connection and a designed attachment point for the tank/pod, to move them out to hang on a structure that was never designed for, or intended to carry anything other than a light. it can’t see it being for any radar related purpose either as I said before the SC.9 didn’t need to have it’s pods moved and other R&D Canberra’s flew with standard tip mounted pods. I just wish my WH793 PN’s had a three view and measurements!


22nd Jul 2013, 22:18
As described in the previous post, there is no plausible reason why the tip tanks would be fitted on PR9 outer wing tips. So why were they fitted thus?

Just in case anyone isn't convinced that the aircraft does have PR9 wings, take a look at this photo:-


I've added a red line to show the obvious similarity between a standard PR9 wing and WH793.

Then there's this illustration:-


Standard Canberra B2 wing in the top picture, and WH793 below. I think anyone can see that the wing tips, aileron trailing edge (no trim tab) and tank fairings are not the same.

So, given that it is a PR9 wing, why on Earth would the tanks (pods) be attached outboard of the normal attachment point?

23rd Jul 2013, 07:40
There is no doubt it is the increased cord PR.9 wing complete with power control surfaces, this is confirmed by my copy of the pilots notes. It's just the tips that were changed back to the standard version, I hope :) !
This is not without precedent the following photo is of 793 obviously before the it's modification at Bedford but after the larger cord was reduced to that of the "standard" PR.9 wing with short/standard span tips fitted.

Until we can find a photo or drawing that confirms or denies that the radar and camera pods were attached to the extended PR.9 tips I'm sticking with my theory.

I've copied some info from my PR.9 AP's, I'm sure it was not beyond the whit of the highly skilled guys at Bedford to engineer a way of attaching and beefing up the PR.9 tips but the big question is why? :ugh:



23rd Jul 2013, 08:54
Pure speculation on my part (I have no knowledge of Canberras apart from one back seat flight from St Mawgan in 1972) so I have my hat and coat ready!

Could it be that the tanks were attached to the normal points BUT the wingtips were shortened? One reason for doing that might be to reduce the flexing moment in turbulence!

I now await incoming!

23rd Jul 2013, 09:02
Well this is the debate really. A lot of people (including John above) think that the aircraft must have had standard B2 wings re-fitted (or more likely the extended PR9 tips simply removed) so that the structural, fuel and electrical attachment point could be used as normal. I see the logic in this, but the problem is that the photos (including those above) clearly show that this isn't the case.

It's all just very odd. There's no reason why the tanks couldn't be attached in the proper position, and yet they evidently were not. I'd just like to find out why as it seems like a very strange arrangement. I'd also like to find a nose-on picture of the aircraft just to clearly confirm this absurdity once and for all! :)

23rd Jul 2013, 09:13

Have you contacted FAST at Farnborough:

FAST - Farnborough Air Sciences Trust - Farnborough Museum - Hampshire (http://www.airsciences.org.uk/index.html)

Most of the RAE documentation, Reports etc were passed to FAST following the destruction of the RAE. Possibly they may have the relevant RAE Mod Drawings etc that should clarify how and why the Pods are attached as they are. Failing that, the relevant trial(s) would have been reported and RAE Reports usually contained the engineering aspects of the trial installations.


23rd Jul 2013, 10:13
I emailed them a couple of days ago so I'm hoping they might be able to shed some light on this. So far no news but if I hear anything I'll post it here :)

As for the above photo of the aircraft in PR7 guise, I'm not convinced that it is a PR9 wing with the tips removed. You'd need to see the upper surface to be certain of that (ie- are the power controls there) but as you can see, it has a standard aileron with a trim tab. That suggests that it's a standard wing, not a PR9 wing with the tip removed. I'm guessing that the underside shot shows the aircraft before it had PR9 wings fitted. Or did it have PR9 wings and then have B2 wings fitted, and then go back to PR9 wings?! It gets more absurd the more you look into it!

23rd Jul 2013, 11:22
If I can enter the argument as a very long time serving Canberra PR9 man, the PR7 prototype in the photographs have the PR9 wing root cord extension but not the square PR9 wing tip extension.
The PR9 tip tanks fit at the original B2 / B6 mounting point and are identical to all other Canberra wing tip tanks.
Although many were modified to fit chaff dispensers/ radar heads and other bits of trial equipment all remain the same three point mounting with explosive bolts. The PR9 wing tip extension, which is not readily removable, is not primary structure and is supported by an extended internal spar which will not carry the weight of a full drop tank.

23rd Jul 2013, 12:51
I'm in agreement on all that (apologies - I think I should have been more clear and said "outer wing" when referring to the photos) but, as I keep saying, what about the photos? I guess it's possible to misinterpret the pictures but on the other hand it would be unwise to dismiss them just because logic says they must be wrong.

Hope somebody out there has a picture of the aircraft taken front-on so that the wing span can be established. I guess that's the only way to settle the mystery?

23rd Jul 2013, 14:12

Plan view

23rd Jul 2013, 14:12

Head on

23rd Jul 2013, 14:25

PR9 and T4 for comparison

23rd Jul 2013, 15:13
... and now all we need is a similar shot of WH793! I'm not holding my breath though but who knows, someone might have one... somewhere?!

23rd Jul 2013, 15:27
...and another one for your scrutiny. Not just me is it? That sure looks like a long PR9 outer wing...


23rd Jul 2013, 16:42
It looks like a PR.9 tip to me too I must admit, but how and more to the point why? perhaps they were using both types? hell, I don't know! Lets hope we can get some more photos, but I'd like to see more than one, or am I asking too much :ugh::ugh:
The outer wing is not removable as a unit, only the tips leading edge tanks (if it's a wet wing) and flap and aileron shrouds can be removed without destroying the wing.


28th Jul 2013, 00:06
Another interesting photo of the aircraft here :-


If you look carefully you can see the tip extension very clearly and the shape of the original wing tip. Also seems to be before the ailerons were modified as the trim tab is visible. Pity this was before the tanks were fitted though!

29th Jul 2013, 19:39
Interesting photo indeed, I thought that was the shape of the original wing tip too, but I reckon it's a mark left from the tip tank. That is the position it is on the PR.9's. I thought about the possibility of extending the tip by adding skin to the original tip profile but that would be, well stupid! it makes far more sense to bolt the newly designed structure to the part of the wing meant for the job. As I think I've said before the wing on the PR.9 is just a development of the B(I)8 which in turn is a modification of the B.5, B.6 PR.7 wing with an increase in chord and span.
I've attached three drawings of the PR.7 wing and tip which I hope will demonstrate the structure of the Canberra wing tip.

this is the T.22 wing but it's exactly the same as the PR.7 in the way it's attached.




3rd Aug 2013, 08:42
I think we have to bear in mind that the photo shows what was in effect the "prototype" so it might have been more of a "botch" job on this aircraft!

My thinking here is that this first tip extension was not completed in the standard fashion (as described in the above drawings) and so the internal structure might be different to that found in a PR9.

The above photo does seem to show the evidence of the standard wing tip buried under the extension, so my guess (and it is just a guess!) is that this aircraft was modified differently to standard PR9s, and still has the existing B2/6-type wing tip still attached, but with some sort of internal structural modification to support the extra wing tip extension, and that this extension was somehow strong enough to support tip tanks?

Well it's a theory at least! :)

3rd Aug 2013, 13:55
Yep it's a theory, any joy from (RAE) QINTIQ or what ever they are called this week on photos?


John Farley
3rd Aug 2013, 19:16
Aero Flight RAE Bedford 1964


3rd Aug 2013, 20:21
Good photo of her John, thanks for posting it. I'm still thinking standard tips.


3rd Aug 2013, 22:40
Lovely photo John, thanks for that!

Sadly, no reply from FAST at all. Not even an acknowledgement, so I guess the mystery of the mis-placed pods is destined never to be solved... ?

4th Aug 2013, 07:48
Don't say that 904! I'm sure we'll get it sorted eventually :hmm:


7th Aug 2013, 15:08
Tiny photograph taken during Concorde trials from Filton. It just about illustrates the aircraft's plan view.

Wonder if anyone else out there might have any photographs from the aircraft's days on the Concorde programme? Worth a shot!


7th Aug 2013, 23:31
It doesn't help with the debate, and no tip tanks, but I thought it was a nice shot nonetheless. :)


Brian Abraham
8th Aug 2013, 02:25
The following may answer some of your questions perhaps

Flight 1 June 1961
English Electric Canberra PR.9

English Electric subcontracted to Luton the task of modifying the Canberra for use as a high-altitude photo-reconnaissance machine.

The alterations required were even more extensive than those superficially obvious, but in particular the 7,5001b Avons were replaced by 11,2501b Avon RA.24s, the intake cowling and accessories were entirely redesigned, the inner wing was extended in chord to reduce t/c ratio, the outer wings were extended in span and terminated in square tips and the whole airframe was refined to reap the maximum reward from the great increase in thrust and altitude rendered possible.

Luton handled all the engineering alterations, and converted Canberra WH793.
Flight development showed the need for various modifications, one of the most important changes being the incorporation of powered ailerons, and the production aircraft manufactured by Short & Harland have a hinged nose housing an ejection seat for the navigator.

Flight 8 May 1969
Once again the photographic reconnaissance version followed the bomber version; this time it was the PR.9 which followed the B(l).8.

The PR.9 was developed by Shorts at Belfast and externally resembled the B(l).8 in that it retained the fighter- type cockpit.

The remainder of the front end was, however, redesigned and incorporated an opening nose which swung open to starboard to permit crew entry.
This variant also had redesigned wings of increased span and greater chord on the sections inboard of the engines, which were now Avon 206s of 10.0501b thrust each.

With the modified wing and higher powered engines the PR.9 was able to reach a much higher altitude.

The first genuine PR.9, XH129, flew on July 27, 1958.

The revised wing shape and engines were tested prior to the first flight of XH129, by fitting them, together with other internal modifications, to PR.7, WH793, this aircraft making its first flight on July 8, 1955.

8th Aug 2013, 07:43
unfortunately there was more than one Canberra used on the Concorde program, but we may get lucky, lets hope! Another point WH793 unlike the PR.9 had Avon RA23's (RA206) a small detail and no help with the wing.

Brian Abraham
8th Aug 2013, 12:24
Info I have to hand says 793 had 10,500lb thrust RA.28 (does not state but I assume Mk 208), where as 129 the first PR9 flew with 11,500lb thrust Avon RA.24 Mk 206.

8th Aug 2013, 16:40
"The remainder of the front end was, however, redesigned and incorporated an opening nose which swung open to starboard to permit crew entry."

The first production PR9 had a glazed nose almost exactly the same as the B(I)8 but following it's loss with the loss of the Navigator all subsequent PR9's were built with the hinged, solid nose with an ejection seat for the Nav.

8th Aug 2013, 16:40
Brian, this is the engine page from WH793's pilots notes from May 1973.

Brian Abraham
9th Aug 2013, 01:14
Thanks canberrasig. I guess I was trying to clarify whether the Mk. 206 was a RA23 or RA24. You say 23 whereas the info I have says 24.

I thought it interesting the difference in the two photos posted previously of the wing trailing edge inboard of the engines


9th Aug 2013, 17:41
Sorry Brian, I'm not too hot on engines, I probably got the numbers all mixed up. The difference in the wing platforms is the one with the extra large cord extension was the original idea for the HAPR.9 wing but it was found after testing that the drag out weighed any advantage gained so it was reduced to what became the production PR.9 wing.


11th Aug 2013, 20:31
I know it doesn't help answer the question originally posed but, having read this thread I was amused to see in the story about the return to flight of a WB57F

here; NASA?s new WB-57F, N927NA, flies for the first time in 41 years | GAR (http://globalaviationresource.com/v2/2013/08/10/nasas-new-wb-57-n927na-flies/?fb_source=pubv1)

the ambiguity re the wing tips. Did they "nearly forget" to fit them before flight? Were they perhaps unavailable for a taxy test or photo shoot?

12th Aug 2013, 08:29
Hi Rory57
Thanks,I have seen it, 41 years after she was last in the air, quite extraordinary! But that's Canberra's for you, you can't keep the old girl down. As for the wing tips I think they were left off just for the taxying phase of testing they are only a very light honeycomb structure and very easily damaged and very close to the ground, so I guess they were just being careful. NASA are thinking of re-engining them with ones from KC.135's that will give them better range/fuel efficiency longer life, and better altitude performance.

15th Aug 2013, 09:01
I found this reference in Uncle Roger's column in "Flight" :-


I wonder if anyone might have any clues as to where Roger Allingham-Mills might be contacted? Maybe he might have some answers? If anyone knows how to contact him (or knows anyone who can help find him) do let us know :)

Brian Abraham
15th Aug 2013, 12:36
Canberra B2 WD952 was powered by a pair of Olympus engines (testbed) and gained the world height record on two occasions: 63,668 ft on 4th May 1953 (Olympus 101) and 65,876 ft on 29th August 1955 (Olympus 102 12,000 lb thrust).

Suffered port engine failure at 50 ft on take off from Filton, Bristol due to compressor blade failure. Force landed wheels up at Cribbs Causway and struck an oak tree which tore off the port wing, undercarriage and elevators, leaving the remainder of the airframe severely damaged. The crew escaped unhurt.

Wreckage (by September 1956) broken up at Colerne after completion of accident investigation procedures.

The Olympus 300 was capable of producing 20,000 lb thrust - would have been an interesting fit.

15th Aug 2013, 16:00
It would be good if he could be tracked down 904, I bet he'd be a very interesting guy to talk to. As for the WB.57F's NASA quote the operating height as 60,000+ comfortably I know they have operated up to 65,000 and the RB.57F's in the USAF days up to 74,000 +.


Brian Abraham
15th Aug 2013, 16:39
Service ceiling for the RB-57F is quoted as being 82,000 feet.

15th Aug 2013, 17:58
82,000 Would that be with a useful load over an operational useful distance?

15th Aug 2013, 22:32
Saw an article on the fleet somewhere in the last year or so , cant remember where, but the re-engining proposal is for ex C-141 engines which are same type but more powerful. Interesting how they have lasted as most books on them in USAF service quoted them as being retired early because of wing fatigue issues. Was this fact or have they now resolved the issues ?

Brian Abraham
16th Aug 2013, 07:08
There are several factors that dictate the maximum altitude of the aircraft; however, the two most prominent variables are the gross weight and the overall drag. The aircraft is capable of higher altitudes later in flight due to fuel burn, while drag is increased by adding wing pods, instrument inlets, and any other items that protrude outside the aircraft.

It seems from the calculator below that 65,000 feet is about all you will get with the aircraft in its current status.

NASA has provided a calculator of the aircrafts capabilities should you wish to fly an experiment.

WB-57 Calculator (http://jsc-aircraft-ops.jsc.nasa.gov/wb57/calculator.html)

21st Aug 2013, 07:38
Sadly, no more news on this subject. If anyone gets an opportunity to mention it elsewhere, please do. It would be nice to find out what the saga was all about :)

21st Aug 2013, 19:25
I'm still working on it! :ugh:

21st Aug 2013, 22:55
Glad to hear it! I'm still keeping my eyes peeled but I get the feeling we've reached a dead end here, but I guess you can never be sure. It's remarkable how so little seems to be known about the aircraft, considering how much information on Canberras is floating around :(

23rd Aug 2013, 09:23
yes true, I bet there is a huge pile of photos of her somewhere that would answer our every question, but until then, we'll just have to keep looking!


10th Nov 2013, 15:25
Well it's taken some time but at last the mystery is over! And it looks like you were right (sort of) It is mounted on the PR.9 type tip but I don't think it is a PR.9 type tip, it looks beefier to me, but what ever there it is! It still begs the question WHY? Why go to all that trouble? Hell, it's a Canberra I guess that's all that needs to be said!

18th Nov 2013, 18:27
Congratulations on finding those photos - brilliant stuff! I'm assuming from the cropped nature of the images that they are part of bigger pictures... can we see? (you can tell I'm a fan of this bizarre machine!).

Good to see confirmation that the vortex generators were retained too :)

19th Nov 2013, 00:10
I've enjoyed the chat about the Canberra. I'm just learning about the aircraft, and had the opportunity to see one last week at the Air Force Armament Museum at Eglin Air Force Base in Florida.

U.S. Air Force Martin B-57 Canberra bomber history, deployment and photographs (http://www.planesofthepast.com/b57-canberra.htm)

19th Nov 2013, 15:31
Try not to dwell on this particular Canberra too much - it'll give you nightmares!