Wing breakage: 109 or Spitfire?

[Juha]

Hello Kurfürst
To put it more clearly, on what you based your claim, that "aileron deflection was limited by half only final the last dive"?

Both the summary of the tests, dated 15 April 43 and the Flight report Nr. 901/274 on tests flown between 15 Feb and 12 March 43 (14 flights) clearly stated that the movement of the ailerons was halved. On the other hand looking again after a long time the Flight report Nr. 879/270 on tests flown between 28 Jan and 4 Feb 43, it didn't mentioned that and in the end demanded enlarged tail and limitation of the aileron movement to 50% before greater speeds were tried

Juha

 

[Milosh]

Does it not seem strange that Kurfurst will take an Aussie document on 100 octane fuel that a person has read as 'gospel', yet questions a report that Glider has read on the Spitfire.

 

[NZTyphoon]

Now, the pages from Morgan and Shacklady presented by Kurfurst as "evidence" that the Spitfire was inherently prone to breaking up. What is striking is how many of the reported incidents can be attributed to external factors;

1): From the line on page 161 "A visit was paid to Farnborough..." the conclusion of the report reads: "It is significant that the panel did not fail at the vertical wall attachment rivets, which indicates that the cracks and rivet failures discussed WOULD NOT have had serious consequences."

2): A PRU Spitfire had "oil canning" of a wheel well plate, but no conclusion was reached as to the reason for this. A scratch connecting several rivets was thought to have been caused by a riveting dolly, which may have led to future problems.

3): Spitfire VBs buckling of top skins was caused by discontinuity of stringers "...and are not of serious consequence." "The buckles behind the main spar are not detrimental to strength and only seem to occur on VB wings."

4): AB200 (Mk VI) incident on 29 January 1942. Damaged wings were replaced and AB200 served on 124 Sqn from June '43 and was sent to 33 MU in October.

5):AA912 violent oscillation of elevator at dive to 465 mph; pilot pulled out..."An examination of mainplane and ailerons revealed no defects....When the tail unit was removed it was found that the tail-plane spars were of the non-reinforced type."

6):One genuine incident of a Spitfire breaking up after entering a high speed dive. Break-up due to "...excessive normal loading produced by an uncontrolled dive at high speed." No mention of how many hours flown, whether the aircraft had taken damage, either in combat or earlier in its career.

7):BL513; Buckling of the fuselage due to heavy landings, which were enough to bend the tailwheel leg. Also, aircraft lost drogue while target towing on previous flight, causing damage to rear fuselage (implied).

8 ): EP335 returned to base after damage during combat manoeuvers and after a high speed dive, during which the pilot blacked out;"The wings and centre-section buckled and tailplane damaged." (By this time EP335 had been in service for 10 months - what the report doesn't say is that EP335 was being used by an OTU at the time of the accident. )

Only two of the Spitfires mentioned were right-offs, with one fatal breakup. There is also a description of several Spitfires crashing due to damage to oxygen regulating apparatus on firing the Hispanos, and over-long oxygen piping in which condensation could freeze - again, these were factors external to the basic design Finally there were problems caused by manufacturing faults which were "rooted out" by the Accidents branch.

What was the point of reproducing these pages? There is nothing startling or new about any of this; the Spitfire was a mass-produced aircraft, subjected to operational wear and tear, not to mention production problems with wrong rivets etc. What is interesting is that many of the incidents described were caused by external factors, while others "Would no have had serious consequences" or "are not detrimental to strength.", something Kurfurst didn't bother to point out.

 

[Juha]

Hello Glider
On Your question in Your message #64 Quote:" what the changes were in the design of the K wing?"

There should have been wheel well doors (and a fully retractable tailwheel) and modified ailerons but according to both Fernández-Sommerau's 109 Recognition Manual and Poruba's and Janda's Bf 109K many 109Ks didn't have the wheel well doors or the fully retractable tailwheel and at least absolute majority of Ks had same ailerons than Gs. K's had big bulges across upper surface of wings as they had bigger 660x190mm tyres but so had also many G-10s. So in essence many K's were aerodynamically more or less identical to G-10s and so were the wings like those in G-10s. It would be interesting to know what was the max permissible dive speed for those non-standard K's. If the critical elements were wheel well doors and/or the fully retractable tailwheel, it sould be the same as for Gs but if the tall tail was the the critical element or the question was that the earlier lower dive speed was overcautious to newer models then it should have been the same as that for standard Ks.

Juha

 

[Glider]

Juha
Thanks for this. There is little doubt that the 1942 restrictions were significant and I would have expected the Luftwaffe to get them increased again as quickly as possible. They may have been over cautious or they may have been defined for a reason we simply don't know.

Anyway thanks again for your comments

 

[slaterat]

I would argue that both the Spitfire and the BF 109 proved that a sucessful 1940s fighter could be built around a weight saving single spar wing. In both cases its what helped to make them great.

Slaterat

 

[Kurfürst]

Really? Why then in Zustand der Maschine reads " Für die ersten Versuchsflüge befand sich die Maschine bis auf die Beschränkung der Querruderausschläge..."

That means that for the first tests flights a/c was standard 109F with wings of the G-model but aileron movement limitations (and an ejection seat, Germans were forefront in these).

Juha

Both the summary of the tests, dated 15 April 43 and the Flight report Nr. 901/274 on tests flown between 15 Feb and 12 March 43 (14 flights) clearly stated that the movement of the ailerons was halved. On the other hand looking again after a long time the Flight report Nr. 879/270 on tests flown between 28 Jan and 4 Feb 43, it didn't mentioned that and in the end demanded enlarged tail and limitation of the aileron movement to 50% before greater speeds were tried

Juha

No further comments seems necessary on Juha's self-contradiction. 8)

 

[Kurfürst]

Does it not seem strange that Kurfurst will take an Aussie document on 100 octane fuel that a person has read as 'gospel', yet questions a report that Glider has read on the Spitfire.

Does it not seem strange that after both of your previous login handles, AL Schlageter and KraziKanuk were permanently banned from this board for just being here to stirr up trouble, you are still here stirring up trouble under a new login... I guess that one is easy to fix.

 

[Juha]

Hello Kurfürst
So we agree that after 9 initial dives from 28 Jan to 4 Feb 43 the test team demanded that for higher speed dives the higher tail a la late Gs and Ks must be installed and aileron movement be limited by 50%.

After these mods 14 further dives were made from 15 Feb to 12 March 43 during which speeds up to Mach .805 was achieved.

Juha

 

[Kurfürst]

Now, the pages from Morgan and Shacklady presented by Kurfurst as "evidence" that the Spitfire was inherently prone to breaking up.

Alas, putting them into quotation marks, or picking out a select few examples when I have already posted to whole text for everyone to read and make up their own mind would hardly succeed in dismissing the documented evidence.

We know that:

a, The Spitfire II manual specifically warn about the low pitch stability of the aircraft and sensitive controls, which can easily lead to structural failure. That pretty much read to me as Spitfire was inherently prone to breaking up, as it was too easy to overload. It wasn't a structural strenght problem, it was a control characteristic problem.

b, We know from Morgan and Shacklady, page 143 that this problem was already encountered in 1941, but the suggested fix, elevator inertia weights were not introduced to Mk Vs at the time,

c, We know that the problem of unwanted tightening up the turn during pullout and consequent structural failures kept persisting into 1942, and lead to numerous total structural failures , evidenced by the 1942 report, and the inertia weights were looked into again.

d, We also know that the inertia weight/pitch instability problem was only half the story, as there were significant problems in co-existance due to aileron instability and flutter, that also lead to structural failures.

e, We also know that there were occasional problems with structural strenght later in the war, see the mention of buckling wings and U frames in fighter-bomber sorties, and signal of prohibition of diving attacks of Mark VIIIs in the Far East.

The evidence is numerous, convincing, and irrefutable I am afraid.

What was the point of reproducing these pages? There is nothing startling or new about any of this; the Spitfire was a mass-produced aircraft, subjected to operational wear and tear, not to mention production problems with wrong rivets etc.

Well the point is to provide verifiable, referenced evidence to the factors that contributed to the Spitfire's structural incidents that lead to loss of aircraft during flight to give the readers objective basis to form their opinion on. After all, thats the very purpose of this thread, to learn about the factors contributing to breaking up of 109s and Spitfires during the war.

IMHO there is a surprising amount of parallel between the time frame and cause of these accidents, despite what fanboys of a specific aircraft would like to tell people, that while the the 'other' fighter was riddled with problems unique only to it, 'his' fighter was utter perfection and completely free of any such defect. The evidence and detailed history of these aircraft show different.

After all, Spitfire fans posting in the thread appear to be somewhat reluctant to share this information with others, being very busy trying to dismiss the evidence posted, and even engage in building CONTHEOs of forged manuals and such silly stuff. The evidence is mounting and tend to show that the Spitfire had its share of problems on its own - some of them (sensitive pitch and instability) were inherent with the design itself, some of them were related to the rather infamously poor quality control at Supermarine. However, from the original question POV of which one is more likely to break up in a dive, it is irrevelant wheter it was a design defect or a production quality defect, the result was the same.

At this point, when evidence is a mountain and all attempts to dismiss every single manual, wartime report and the respected Spitfire Bible by Shacklady and Morgan that was shown have failed, Spitfire fans start to be extremely liberal, and there is suddenly talk of 'mass-production', 'operational wear and tear' and so on. Oddly enough, these causes didn't apply to the 109 a few pages before.

 

[Kurfürst]

Hello Kurfürst
So we agree that after 9 initial dives from 28 Jan to 4 Feb 43 the test team demanded that for higher speed dives the higher tail a la late Gs and Ks must be installed and aileron movement be limited by 50%.

Yes and they reached 850 km/h to 890 km/h speed during those trials.

After these mods 14 further dives were made from 15 Feb to 12 March 43 during which speeds up to Mach .805 was achieved.

Juha

Yes after limiting the ailerons deflection to half, they reached speeds 16 km/h higher, up to 906 km/h, than before limiting the ailerons.

Also it should be noted that they widely exceeded the official dive speed limitations of the Bf 109F both in the dives with aileron limitation and both in the dives without aileron limitation with no serious incident.

 

[Juha]

Hello Kurfürst
yes, and after all the plane was not a normal F but F with stiffer wings of 109G.

Juha

 

[Kurfürst]

No, Glider was not making this up - as Quill has described, the problems were caused by bad loading at squadron level, which led to problems of Spitfire Vs breaking up in a dive.

Indeed Glider did not make that up, it was you who made it up, in a previous thread, and Glider was only quoting your claims, believing he read them in a report.

Contrary to your claim, it had nothing to do with 'poor maintenance' at a squadron level.

Contrary to your claim, it was not limited to a 'few squadrons'. You refer to Quill having said that, which is false, and it is actually your own very liberal interpretation of his words: "However the importance of these loading instructions was not generally appreciated in squadrons and in the daily round of operational activity they tended to be disregarded. ... There was thus a real chance that, as of that moment, in almost every squadron in the Command Spitfires were flying in a dangerous state of instability...."

That is very far fetched compared to your claim that it only effected only a few squadrons - Quill states exactly the contrary.

Also contrary to your claims, the main cause of this defect was a faulty decision.

Morgan and Shacklady details these on page 143: the RAF was well aware that the Mk V may have problems with the CoG shifting as a result of added equipment (given that it was originally meant as an interim solution, basically a Mk I with a new Merlin 45 engine). The idea of adding inertia for the Mk VA and Mk VB was already considered in June 1941. As a result of dismissive comments from pilots from operational Squadrons with this installation (compaints of inertia weights making the Spit difficult to land and reducing its manouveribility), and trials at RAE it was decided to fit the inertia weights only to the Mk Mk VI, PR IV, VI, VII and Seafire I and II.

However, the inertia weights were not to be fitted I, II, and V in 1941, provided several items were to be deleted. In retrospect this was a faulty decision, and lead to several fatal accidents with the MK V involving total structural failure, and prompted another investigation in early 1942 (the paper I have also posted, which you also implied to be forgery or manipulative ). Eventually the inertia weights were to be fitted after all, but not until several planes and pilots were lost to this design defect, that could prove fatal with the type's inherent low pitch stability characteristics.

It's very easy for Kurfurst to make all sorts of claims, based on selected pages (including a set of "Pilot's Notes", the provenence of which is unknown...),

Of course its very easy for me to make statements, because, unlike yourself, I am fully able to back them up with a mass of primary and secondary source, and unlike you, I am not forced to desperately make up pitiful conspiracy theories about 'selected pages' and petty, underhand implications that a manual posted as evidenced is my forgery - BTW Glider just posted the same manual in another thread, and I haven't sent it to him. OOPS!

but I don't believe he had the experience of Quill in actually testing and approving the flight qualities of all marks of Spitfire.

What the heck are you babbling about..?

The evidence posted come from

- the 'forged' Spitfire II manual, issued by the Air Ministry. It certainly not approves of the stability characteristics, which are described to be poor and potentially dangerous;
- the 'selected' 1942 reports of investigating Spitfire structural failures in pullouts - surely those serviceman concerned and responsible because of these wing failures were a bunch of idiots, too...
- Morgan and Shacklady, authors of by far the most definitive history of the Spitfire, who devote two chapters of aileron related and diving accidents in their book. Surely they were doing this because they though the issue was insignificant...

Besides Quill is also in good agreement with these sources, describing the same problems, and saying something utterly different than what you put into his mouth. 8)

 

[Kurfürst]

Hello Kurfürst
yes, and after all the plane was not a normal F but F with stiffer wings of 109G.

Juha

Yes I would believe there would be very little point in testing a model (109F) that by 1943, when the test was done, was practically retired from service. In any case the US Material Command document shows there were no problems with the 109F wing/aileron either.

Anyway, its nice to know that the diving limitations of the Bf 109F/G could be considerably exceeded without serious ill effects, using extreme diving methods (vertical dives at full power from maximum altitude, and subsequent violent pull up) as was shown during the trials.

 

[Kurfürst]

More from Morgand and Shacklady, Spitfire: The history.

It would appear that the invastigation of series of Spitfire accidents related to structural failures in flight were not only rooted in pitch instability, but also in aileron instability experienced in flight.

Other salient point being the sepeation of the tail unit in flight at frame No.19 due to lack of weak design of the tail unit. On the good side, the pilot was usually catapulted out of the aircraft, presumable through the plexiglass, when this occured.

Details are below:

 

[Kurfürst]

AA 876, disintegrated in dive at 520 mph. Via Morgan and Shacklady: Spitfire, the History.

 

[Glider]

Indeed Glider did not make that up, it was you who made it up, in a previous thread, and Glider was only quoting your claims, believing he read them in a report.

Kurfurst.
First. I have adressed this before and you are ignoring what I said. I pointed out to you that its difficult for me to repeat someones claims if I made them first.
Secondly you never did say what that report said only showing the front cover.
Lastly At the end of the day the number of instances are small compared to the number produced and in service.

Have you any numbers for the german losses due to accidents?

 

[DerAdlerIstGelandet]

Play nice everyone...

 

[NZTyphoon]

Indeed Glider did not make that up, it was you who made it up, in a previous thread, and Glider was only quoting your claims, believing he read them in a report.

Contrary to your claim, it had nothing to do with 'poor maintenance' at a squadron level.

This is HEROIC! Kurfurst says the problems with the Mk Vs had nothing to do with poor maintenance at squadron level. First he claims that I made it up that Spitfire Vs were being badly loaded at squadron level, yet the paper, reproduced below (courtesy of KF), clearly states

( 1st para) This report forms part of an investigation...undertaken...as a result of several accidents to Spitfire V aircraft in service... (2nd para) The purpose of the investigation was to study the handling qualities of the Spitfire I and Spitfire V with particular reference to the dive and pull-out and tight turns. The effects of centre of gravity position, inertia weight...were to be obtained

He then quotes my quote from Quill...:

Contrary to your claim, it was not limited to a 'few squadrons'. You refer to Quill having said that, which is false, and it is actually your own very liberal interpretation of his words: "However the importance of these loading instructions was not generally appreciated in squadrons and in the daily round of operational activity they tended to be disregarded. ... There was thus a real chance that, as of that moment, in almost every squadron in the Command Spitfires were flying in a dangerous state of instability...."

That is very far fetched compared to your claim that it only effected only a few squadrons - Quill states exactly the contrary.

This was my quote from Quill, with my comments (post #80)

The Mk V aircraft was...in full service with Fighter Command and,...a fair amount of additional operational equipment had gradually crept into the aircraft, most of it stowed within the fuselage. The aftmost acceptable position for the aircraft's centre of gravity had been fixed in the mormal course of flight testing by the firm and by the A AEE....Any rearward movement of the centre of gravity in service, for whatever reason, would begin to destabilise the aircraft. Therefore, for each sub-variant of the Mk V detailed instructions for the correct loading of the aircraft were issued to squadrons....However the importance of these loading instructions was not generally appreciated in squadrons and in the daily round of operational activity they tended to be disregarded." (pages 232-233 -Quill goes on to describe 65 Sqn's Spitfire Vbs which were found to be dangerously unstable)

"There was thus a real chance that, as of that moment, in almost every squadron in the Command Spitfires were flying in a dangerous state of instability....Up to that time there had been a distressing and increasing incidence of total structural failure of Spitfires in the air, which was causing great comcern in the MAP and especially at Supermarine." (pages234-235) Once the bobweights had been introduced and, in later marks, the modified mass balances on the elevators...it was statistically established that, as soon as the longitudinal stability of the Spitfire was thus brought under control, the problem of the unexplained breakings-up of aircraft in mid-air,...'softly and suddenly vanished away'." (page 238 )

What is interesting is that Quill points out that the majority of Spitfire Vs in service may have been dangerously unstable. If this was the case it is even more striking how few of them actually broke-up.

The report, one page of whick Kurfurst uses to imply that all Spitfires were inherently likely to break-up, is dated April-July 1942, and is one of those written during the investigations of the problems described by Geoffrey Quill.

Ah, Yup : ; 'nuff said...8)

and prompted another investigation in early 1942 (the paper I have also posted... )

So, this paper, reproduced above, had nothing to do with the problems described by Quill...

Also contrary to your claims, the main cause of this defect was a faulty decision.

Not that I actually made such claims...but do go on.

Morgan and Shacklady details these on page 143: the RAF was well aware that the Mk V may have problems with the CoG shifting as a result of added equipment (given that it was originally meant as an interim solution, basically a Mk I with a new Merlin 45 engine). The idea of adding inertia for the Mk VA and Mk VB was already considered in June 1941. As a result of dismissive comments from pilots from operational Squadrons with this installation (compaints of inertia weights making the Spit difficult to land and reducing its manouveribility), and trials at RAE it was decided to fit the inertia weights only to the Mk Mk VI, PR IV, VI, VII and Seafire I and II.

However, the inertia weights were not to be fitted I, II, and V in 1941, provided several items were to be deleted. In retrospect this was a faulty decision, and lead to several fatal accidents with the MK V involving total structural failure, and prompted another investigation in early 1942 ... Eventually the inertia weights were to be fitted after all, but not until several planes and pilots were lost to this design defect, that could prove fatal with the type's inherent low pitch stability characteristics.

And so? I happen to agree that this was an appalling decision. Doesn't change what I said in #80, that the paper presented by Kurfurst was written because of the problems of Spitfire Vs falling apart in 1942, exacerbated, as Quill says, by poor maintenance at squadron level - up until now Morgan and Shacklady p. 143 hadn't been mentioned at all.

- the 'selected' 1942 reports of investigating Spitfire structural failures in pullouts - surely those serviceman concerned and responsible because of these wing failures were a bunch of idiots, too...

Quite possibly

Of course its very easy for me to make statements, because, unlike yourself, I am fully able to back them up with a mass of primary and secondary source??, and unlike you, I am not forced to desperately make up pitiful conspiracy theories...

It was Glider who provided the Spitfire II Pilot's Notes in full - not KF, who posted a selected set of pages on photobucket; I will take Glider's word, rather than KF's. BTW page 9 of the manual, under Fuel, oil and coolant states
Fuel.........100 Octane (Store Ref.34A/75)

This might be of interest. It should be noted that the words are very similar to Kurfurst's paper. He did post a link once and there were some problems with the paper he put a link to.

Namely it was dated June 1940 but gave the instructions for firing 2 x 20mm and 4 x LMG or 8 x LMG. Also it had the details for both 87 and 100 Octane fuel. In June 1940 the were no Spit IIB and they all had 100 Octane fuel.

The one I have posted is dated July 1940 and despite titled Spit IIa and IIb only gives the instructions for firing 8 x LMG. Also the fuel is only 100 Octane. This would be correct as in July 1940 all Spit II were in the front line and only had 100 Octane.

Kurfurst's paper must date from around June 1941 when Spit II were being issued to training command who did use 87 Octane.

It should be noted that all the above claims by Glider are made up on his own regards the contents of the manual - it doesn't contain anything like he says, in fact he just posted exactly the same manual I have...

Now according to KF Glider is telling porkies about the Pilot's Notes - Supermarine Spitfire Mk IIA - IIB - Merlin XII Engine yet it clearly says: Page 9...(Fuel, oil, coolant) Fuel... 100 Octane (Stores Ref. 34A/75) , p. 5 (7) ... 8 Browning .303s machine guns are mounted in the mainplanes... [/U] Then KF claims this is the same manual that he had just posted, thus contradicting his claims about Glider's comment regarding the "contents of the manual". ( Note: The Pilot's Notes on Zeno do quote 100 and 87 octane fuel and both armament arrangements.)

 

[Glider]

This may be of interest. Its the link Kurfurst posted to the copy of the Pilots Notes he was using. It shows the hard copy Kurfurst posted, where the pilots notes came from that he used and my observtions as to some of the differences between the notes.

This is very different to notes I posted.

http://www.ww2aircraft.net/forum/aviation/use-100-octane-fuel-raf-pt-2-a-20108-8.html

Kurfurst I would appreciate your withdrawl of the accusation that I was making things up.

PS there is a clear overlap between this thread on the one onSpitfire vs 109. Can I suggest one of them be locked to save confusion.