X1 or M52 – who's right – who invented the all moving tailplane first?

There’s always a reason for the axe and often its money – other priorities for finite resources. We are today in a fashion of disparaging “experts”, in part because their turgid Reports can be presented to fit their funders’ wishes.

M.52 had been funded by B.Lockspeiser (BL), D.Scientific Res.(Chairman, MAP Supersonic Cttee.), 29/12/43: its purposes were: as a flying test bed for Whittle’s reheated by-pass W.2/700; to upgrade Miles’ razor wing work; to explore the transonic regime. Miles had no distinct qualification for any such work: “very good at biffing out small cardboard (types, hadn’t) produced (subsonic) let alone supersonic ones” M.Morgan,MoS/DCARD,Turnill/Reed,P108
(prototype metal Monitor in Experimental Shop), but MAP Cripps’ wife Isobel had been entranced by Blossom Miles on a Woodley Factory visit, 10/43: “unusual and enterprising designs” supportive of what BL saw as “fantastic problems” D.Wood,Project Cancelled, P29.

One of the we wuz robbed books gives us the underlying issue: W.Brown/D.Bancroft, M.52-Gateway to Supersonic Flight,Spellmount,2012,P.85: PM, anticipating VJ Day by end-46, 15/1/45 instructed Munitions industry effort to be confined to projects offering “substantial operational” capability by autumn,’46. MAP officials were thus insubordinate/ultra vires in continuing M.52 from that day. And again from 2/9/45 when Miles became unable to draw any material from the Woodley store of US’ Lend/Lease Administration… because the Allies now had no enemy. Supersonics had no civil application.

(By then Sir) Ben., DGSR(A)/MoS 2/46 got round to chopping it a year after PM had instructed, after (incredibly) securing a budget for Aircraft Research (UK was broke and cold). He selected innovations with civil potential – Flying Wing, laminar flow, VG: “funds (to) begin exptl. work” on models (it took until mid-’48 to elicit interest from BOAC’s MD, Whitney Straight. J.E.Morpurgo,Barnes Wallis,Longman,72,P313). He separately extracted funds for Brabazon Committee-inspired civil projects. Well done, that man! May I suggest we here are happy with those achievements, while some wish he could have found yet more of our money for M.52 to continue until Miles’ 19/11/47 bankruptcy (for unrelated, even non-Aero, reasons).

The “pilot risk” issue can be taken as smoke and spin. A reason for cancellation was needed that did not impugn the 12/43 spending decision made by, ah, BL, and, ah, the now President of the Board of Trade, Cripps.

The problem was visibility of what happened to an aircraft as it transitioned from the transonic (ie a high speed at which some part of the aircraft was above Mach one – which could begin at anything from 400mph to Mach 0.95 depending on shapes) and the supersonic (when all of it was). No tunnel in the world could do that 1943 to 1946, and this un-testable transition point was also exactly where the perceived ‘barrier’ was. Hence rockets etc. The Americans persisted with the manned ‘suck it and see’ approach, possibly largely for PR reasons. It’s illustrative of the doubts everyone had that they didn’t put one of their top test pilots into the X-1.. and some say it’s because one of ours was publicly earmarked for the M-52 that it was cancelled.

It comes down to what those reports – particulary ref. 6, Hutton and Gamble “High-speed wind-tunnel tests on an aircraft designed for supersonic speeds (Miles E.24/43). R. & M. 2404. July, 1945” actually said. I would be very surprised if they categorically stated anything that really justified cancellation, but if they do, that’s one less conspiracy theory.

I have just found the RAE Vickers report – it’s R&M 2835, not 2357 – that’s what threw me initially.

In fact it reads: “the Miles Company put forward a scheme for a supersonic aircraft, Ref. 1 (later known by Specification No. E.24/43). But the existence of such a proposal merely drew attention to our ignorance regarding flight conditions at and near the speed of sound, and to the need for research. Suggested research methods were the attachment of aerofoil surfaces to the tail of existing rocket missiles, the construction of a very high-speed rail track, and the dropping of heavy bodies from very high altitudes. With the gradual accumulation of knowledge it became clear that the E.24/43 was unlikely to reach sonic speed and when wind-tunnel model tests indicated the same serious loss of longitudinal stability at high subsonic speeds as was then characteristic of all existing aircraft (Ref. 6), the wisdom of continuing with this design was questioned. The decision was reached to acquire preliminary experience of flight under transonic conditions using rocket-driven pilotless scale models”.

So between us Aeronut and I have given a classic example of misinterpretation and selective use to back up a pre-conception – I apologise for seizing on ‘transonic’ and attacking the claim of ‘knowledge’ that the M-52 wouldn’t reach transonic speeds when that wasn’t what was actually said.

The lack of a transonic tunnel was a British and Americans thing.
According to “Feddens Mission to Germany” Appendix 1(b) the Volkenrode A9 tunnel had demonstrated steady flow at “Mach 1.0 to 1.5 and could readily maintain continuous operation.” Additionally the DVL 13MW continuous flow tunnel in Berlin could test at Mach 0.95 as early as 1940.

Yes. So the ‘knowledge’ seems even more tenuous. It seems we are back to the problem of the ‘blind spot’ between Mach 0.8 and Mach 1.3 which most faciliies had at the time. It may well be the M.52 couldn’t indeed be made to ‘go transonic’.. but that was a failing of the available tunnels, not the aircraft. This situation seems to have been ‘spun’ somewhat.

Just reading a bit more and the problem of using small supersonic tunnels to preform stability assessments and there’s considerable uncertainty with the influence of reflected shockwaves. Also the NPL tunnel couldn’t do transonic, it had a lowest operation stable speed of 1.35M. To be fair this for the time was seriously cutting edge, as all the previous testing had very likely been simple ballistic body shapes, no wings and the like which throw off a far more complex patterns of shock waves. I believe the NPL tunnel chief scientist (Dr Maccoll)advised Miles & the RAE that any results should be regarded as indicative trends at best. Really he’s saying I don’t trust the data so why should anyone else. This can rapidly lead very negative interpretations which would further explain the poor stability reported in the later RAE report.

So true. Also understanding what the data is telling you (Sidney Camm and the Hurricane wing). I am not convinced that wobble on starting a run would be interpreted as instability of a design – the people running the tunnel would be professional scientists who would be experienced in the behaviour of models in their tunnel and would know what data was relevant and what wasn’t.

They would have been the source of the content of any report. Any misinterpretation of that can surely not have been accidental? I am coming across more and more examples of willful misinterpretation of aeronautical research by decision makers in British and US administrations at this time, the more I read – and the feeding back of official lines into the intro pages of RAE and NACA reports (eg. P-38 dive flaps). That line about accumilation of knowledge – not a belief or an opinion but apparently a knowledge – that it wouldn’t even reach transonic speeds suggests someone jumping on things to justify a decision already made. Especially when one considers the choice of ‘transonic’. Transonic speeds for a partucular design are those at which the flow over some part(s) of the aircraft but not all of it has a relative velocity above Mach 1, and the later an aircraft reaches transonic speed – the higher the critical Mach – the faster it will go and the easier the transition to supersonic. Might this be someone deliberately misinterpreting ‘the aircraft reaches Mach whatever without going transonic’ as ‘the aircraft won’t reach a speed at which something goes locally supersonic’.. which is an unlikely scenario when a P-40 could.

Not teaching anyone to suck eggs about the transonic stuff, btw. Just ‘showing my working’.

Aeronut
I’m not questioning if wind tunnel testing was done;- clearly the surviving models and pictures prove that beyond any doubt. The point I’m making is that the supersonic wind tunnel testing was only preformed on the extremely primitive small, intermittent tunnel at the NPL (Teddington), the results of which were used to justify project cancellation, when the RAE had access to fair superior equipment at Volkenrode. The small intermittent tunnels had short run times measured in seconds, and the shock of introducing the air would cause the model to bounce around;- trying to assess model stability under these conditions is hopeless. As you quite correctly say the Vickers models worked when flawed wind tunnel results indicated they wouldn’t.

Kelly Johnson assessment that the larger constant flow tunnels made the X aircraft obsolete was based on much better data available from the bigger tunnels. He had to wait until 1948 while the RAE had access to this in September 45.

So why did the RAE make such an important decision based on such poor data when they had the means to get high quality data? BTW I don’t believe it’s a conspiracy, just a British standard management mess up.

As I’ve told people all my working life “good data = good decisions”

The RAE report (Aero 2357) on the RAE/Vickers transonic model shines some light on the subject.
It mentions the reason for the cancellation of the E24/43 (M52) as “accumulation of knowledge that it wouldn’t reach transonic speeds” and “wind tunnel tests that showed a serious loss of longitudinal stability at high subsonic speeds”. There was a further concern, that of “safe escape of the pilot in the event of an emergency bail-out”.
The rest of the report describes the trials and tribulations of the test vehicle programme and the successful third flight when it reached a maximum of 1.38 Mach which would seem to vindicate the Miles design including the tail plane.

Stick back
Apologies but a few corrections;-
The M52 project/contract termination notice was passed to Miles on the 13th March 1946 and the DH108 crashed on the 27 September 1946. Arguably the RAE/Miles failure with the M52 directly lead to Sir Geoffrey death.

America had a small 9inch supersonic Windtunnel operating at Langley prior to the end of WW2. Similarly the UK had one very small but operable intermittent supersonic wind tunnel at the NPL. However the Germans had about ten, four at Volkenrode alone, the largest of which had a 31inch working section(Tunnel A9 @ 1-1.5M, continuous flow). An even more impressive in terms of size to speed supersonic tunnel at Kochel and a even larger tunnel at another location (can’t find the ref). By the Autumn of 1945 the RAE had these two aforementioned facilities working and producing test data to their instructions ….but neither the M52 or DH108 were tested. Why? A massive error, largely unrecognised, which cost Sir Geoffrey his life and UK the lead in Supersonic flight.

The American tunnel you’re referring is the 40inch continuous flow commission by NACA. I wholeheartedly agree that tunnels of this size are what was really needed to comprehensively understand the transonic stability issues. I don’t believe the usual M52 conspiracies but would like to know why the RAE failed its own industry so badly.

love Miles Aircraft but i really wish this silly conspiracy would die i think the biggest factor leading to the cancellation of the M52 was Geoffrey DeHavilland jnr’s fatal crash in the DH swallow a few months before..Bureaucrats are naturally risk adverse and they could probably see it happening again killing another one of Britains top pilots. The M52 was more complicated than the X1 and there was a high likelihood it would have had teething problems and the Americans still might have beat them. finally NACA had managed to develop and operate a supersonic wind tunnel (of which data they shared with the British) in early 1948 thus making both the X1 and M52 somewhat redundant Lockheeds Kelly Johnson was quite dismissive of the whole Xplane program (there were no Lockheed research or X aircraft)…he said while they were playing around with useless research aircraft in the desert his team was already working on what would become the F104 and U2. Finally being first hardly gave Bell Aircraft any great advantage they made one more fixed wing aircraft the X2 and that was it….had they not been involved in rotor wings they would have gone the way of miles aircraft for certain.

Got sod all to do with all flying tailplanes.. Why , oh, why, oh, why are you a dullard!

The Tizard mission to the U.S. in 1940 included Taffy Bowen, who took with him a cavity magnetron. Bowen’s book Radar Days described the meetings he had with an American admiral? who gathered the top people from the U.S. radio industry, with Bowen, and they designed the predecessor to SCR 520, which developed into SCR 720, better known to us as A.I.Mk10. the UK then purchased these sets from Westinghouse. SCR720 was developed specifically for the Black Widow, but was most effectively used in the Mosquito, the Black Widow being too long in development, while the Mosquito was ready made, waiting for this very effective radar. Bowen had experience of operating the earlier British built radars in the air, and had been Watson Watts’ leading man on airborne radar. The basic concept of SCR 520 was inspired by Bowen, so it could be considered a joint project. I would recommend Radar Days to anyone interested in the development of radar.

I hate to risk reviving a dead horse, but post #99 brings up the subject of radar.

I was recently reading a book on American Navy ASW blimp operations which went into great detail on radar types.
The author gave full credit to the UK for early work on the subject but basically reported that the U.S. was tasked with making necessary improvements and upgrades and producing units for both countries. While he was specifically referring to search radar, I would assume it would also apply to AI units.

Anyone here able to elaborate? Were many/most sets, US-made?

He also said the U.S. developed the expendable sonobouy.

Chris
You talk of the alleged Autumn 1944 meeting/data exchange between Miles and Bell as it is a matter of established fact. It’s not;- there are no period records which confirm this ever took place;- there’s not even a date or attendance which is agreed by the claimants.

FG Miles, B Miles, E Brown, & D Bankcroft, all fine and upstanding Brits, claimed sometime after the war it happened, but please don’t forget that E Kotcher, B Hansen, P Emmons, J Stack, W Williams, & R Gilruth, those who defined the Bell X1, all fine upstanding Americans, firmly deny it took place or ever seeing any Miles data. Despite extensive searches in the American archives by Dr Richard Hallion, nothing more than vague references to the M52 have been found. It’s true that the Bell archive from the time is fragmented, but considering the amount of unexpected British data from other projects that has been found, I cannot subscribe to the suggestion that there has deliberate cleansing of the files to cover things up. Equally the Miles archive has nothing on the Autumn meeting but contains details of Doctor Clark B. Millikan, acting Director of the Guggenheim Aeronautical Laboratory at Caltech visit to the Miles factory on the 28th June, 1945, where he was hosted by Mr. & Mrs. Miles, and the Ministry of Aircraft Production M.52 representative, Group Captain Banditt and a second American visit to Miles Aircraft took place on 8 july 1946 by Major E.H. Hall/Major Kent Parrot of the Air Technical Section of the Military Intelligence Division (note;- both of these recorded visits were after the X1 design was finished and neither recorded passing over detailed data);- if these are deligently recorded why are details of the Autumn meeting missing?

We simply don’t know who is telling the truth and probably never will. Therefore I believe it’s important we correctly report the facts and don’t defacto brand either party as telling lies.

4 years since this one was done and dusted: which TV documentary kicked this one off again?

The M52 flying tail debate rumbles on. The worst aspect has been some of the TV documentaries where producers try to over dramatise the subject for a peak time dumb audience. Interviews are subject to cut and paste and sometimes reverse what the first hand experts are trying to say. Sadly these documentaries move on as historical fact because the list of experts would seem to endorse whatever angle the producer wishes to portray.

The all moving tail plane has been around since the first flight. For instance the 1914 Morane Type N had one in ignorance of the basic stabilityimprovement of the fixed stabilizer with an attached elevator. The Morane was therefore very twitchy especially allied to wing warping. Later designs with a stabilizer and elevator, Fw190, Me109E, Gladiator, Macchi200 and Me262, all incorporated a moveable stabilizer to adjust pitch to neutral as speeds increased and downwash angle changed. This allowed a pilot to trim to a speed and make control more comfortable. A form of datum trimming. The Lysander used a moveable stabiliser to adjust for the large speed range of STOL.

In 1942 when the RAE was investigating transonic flight it was known that the centre of lift of aerofoil moved aft at higher Mach numbers therefore making pitch control heavier both in trim and weight due to airspeed and aerodynamic forces. Because wind tunnels choked above about Mach .82 no further information about the flow over the stabiliser could be determined. D.Relf of the RAE published a paper in 1942 which outlined a design for a transonic aircraft. It had a geometric aerofoils and an all moving tailplane without an elevator. The paper indicated that the powerful tail control was necessary to counter the problem of pitch and further advised that aerodynamic forces would require the control to be powered. The original six point A4 spec for the M52 specified a powered all moving tailplane with no elevator and this must have come from the RAE research.

At this time knowledge of shockwave formation over aerofoils in the transonic region was limited by the inability of wind tunnels to work in the regime .85 to 1.2 Mach. Flight testing and flight reports from manufacturers and pilots ‘in the field’ gave a confused picture because different designs demonstrated different Mach effects and control problems. We now know that there are several effects which occur in the transonic region and the effort to differentiate between them caused confusion.

The M52 was designed with fully powered all moving tail plane in response to the RAE data for a powerful pitch control. Provided the pilot and engineers understood the refinement of control response with varying speed the idea would have worked though out the transonic range and beyond. A subsonic stabiliser with an elevator obeys the aerodynamic rule that movement of the elevator changes the flow across the whole control surface. In other words its effect is upstream. This does not happen when a shockwave starts to form and move across a control surface and the control therefore become steadily less effective and even more so when the shockwave arrives at the elevator hinge point. This would not have been known at the time the M52 and the Bell X1 were designed.

Bell were given the specifications of the M52 during a visit to Miles in September 1944 and Dizzy Bancroft of Miles and Robert Woods of Bell would have discussed the details including the all moving tail. The Gillette Falcon with the thin wing and all moving tail had been flown by Miles in the month before. In June 1945 Woods had been in Oberammergau discussing the Me1101 design with Voldemar Voight its designer. This had a moving stabiliser and elevator. Although not directly connected to the X-1 project NACA flight tested an all moving ‘slab’ tail plane on the XP-42 in the middle of 1946 which confirmed that the device was useable at high speed and speculated that this would need power boost at Mach number near unity. The X-1 stabilizer was electric powered and moved 5deg up and 10deg down at a rate of 2deg per second.

In summary. The events discussed took place between 1942 and 1946 a period of four years when groups in Britain, America and Germany were researching the same problem for slightly different reasons. In four years of meetings and discussion a lot of information can be subject of debate. As a designer I know that one only has to throw the germ of an idea into the ring for some bright spark to take it the next step and draw new conclusions.

The British were first to specify the slab stabilizer with power control. They did this to resolve the perceived problem of pitch control with the change of centre of lift at transonic speeds. There was no mention of shockwave interference on the elevator hinge line. Although the Americans built the X-1 with a powered moving stabilizer it also had a conventional elevator which means that they also did not predict the effect of the shockwave on the elevator hinge line. It was only when the elevator became totally ineffective in flight testing at Mach 0.94 (0.997 true) that data showed up the problem of the shock wave passing the elevator hinge line. It was Jack Ridley who speculated on the use of the stabilizer power trimmer as a possible effective control to push through the barrier. The trimmer was there as a conventional sub sonic control. One could say that the suggestion that Yeager try it was speculative and entrepreneurial, even desperate. The success lead to understanding the reason for the loss of elevator control in the narrow band before supersonic speed was achieved. The M52 would have had its development problems as did the X-1 but the all moving tailplane would have ensured a smooth ride into supersonic region. NACA discovered the hinge line problem as part of the flight programme. The all moving tailplane followed as a natural benefit.

I was wondering:
Could it just be they had an old copy of the October 1946 issue of “The Aeroplane Spotter” lying around in the Muroc Army Air Field crew room?
There’s an article titled “High Speed Research” in it (page 244) which, among other interesting things, describes the use of the movable tailplane by Miles to overcome control locks at high speeds.
So much for TOP SECRET!

http://museumofberkshireaviation.googlepages.com/high_speed_research.pdf

Obviously there is an important difference between a variable incidence tailplane and a flying tail. Put simply the former is used to trim the aircraft and the latter is used for primary control in pitch mode. Examples are for instance the Focke Wulf Fw 190 with its variable incidence tailplane incorporating a conventional elevator, movement of the tailplane being controlled by an electric motor and the North American F100 Super Sabre with its slab flying tailplane without elevators controlled hydraulically.

My question is suppose the pilot of a Fw 190 is in a terminal velocity dive. The elevators are almost ineffective. What would happen if the pilot tried to pull out by operating the variable incidence tailplane. Assume the electric motor with its worm drive and screw jack is powerful enough to overcome the aerodynamic forces on the tailplane. What will happen? Does he not have in case of emergency a stand by flying tail. Perhaps it will just rip off the whole tail unit like the early Typhoons.

Talking of Typhoons but the Eurofighter variety why when the aircraft is at rest does the canard foreplane assume an incidence of nearly 90 degrees? It could not possibly fly with it like that under any conditions could it?

As this thread is loosely on the topic of the race to achieve Mach 1, some of you folk here will probably enjoy this recent podcast from my Wings Over New Zealand Show series:

Noel Kruse – The Race For Mach 1
http://www.cambridgeairforce.org.nz/WONZ_Show_Two.html#Noel_Kruse_RNZAC