Thanks Bruce.

That’s what I was asking, if the camera angle or film used distorted anything, and that seems to be the case, as in the film, it’s wings resembled the Ghost Vampire, which was used to test the Ghost engine for the early Comets and lateer the Venom series.

This distortion doesn’t show up on the other films presented on British Pathe’s site, so it seems to be a deal of circumstance.

But as for the other Vampire question, of the aircraft in the DH Hatfield video, it shows a Vampire being fitted with flaps that are joined by a fairing that lines up with the underside of the tail booms while almost other Vampires I’ve seen have their flaps split in two by the tail booms, and it seems that this wasn’t fitted to production aircraft. I can’t really see on the tail where the ID number is, but the paint colors remind me of some photos taken at Hatfield in an old issue of Flight of the Ghost Vampire, but I didn’t see the normal “circled-P” markings that the Ghost Vampire had near the RAF roundels. Could it be the Ghost Vampire or another R&D aircraft?

This un-ID’d Vampire appears at about 0:20 and the rear view shows the flaps that I’m talking about:

http://www.britishpathe.com/video/de-havilland-aircraft-factory/query/Vampire

The article says that the I.Ae. 24, when originally engined with Merlins, looked and roughly performed similarly to the Mosquito, just as the I.Ae. 30 twin engined fighter looked roughly similar from a distance and have performance similar to the DH Hornet (the I.Ae. 30 and the Hornet were powered by versions of the Rolls-Royce Merlin 130 family of engines).

The DH 101 was a heavy bomber built to RAF specification B.11/41, and, at least on Wikipedia’s list of DH aircraft, was ID’d as the the DH 99 (which they apply as being an early all-metal version of the DH 100, ultimately to become the Vampire), while the DH 102 was a slightly larger, high altitude version of the Mosquito. It was slightly larger than the two-stage Merlin powered Mosquito bomber/PR aircraft, and was part way in size between them and the Ju-88, and (like the later Mosquito PR/bomber/very late war night fighter aircraft) was intended to be powered by the Merlin 60 series family of R-R Merlin engines.

The problem that the DH 102 seems to have had is that it ran head on into de Havilland being preoccupied with the Vampire (an aircraft that the RAF requested that they design to be a single engined jet fighter), the Hornet (a private venture single seat twin engined fighter), and that DH was involved with fitting the two-stage Merlins to Mosquitoes to give more power so they can handle heavier bomb loads and gain higher ceilings.

The project it seems was that the DH 102 was designed to carry a 4000 lb bomb load and be capable of a 400+mph top speed, both of which were just as easily met by the Mosquitoes powered by two stage Merlin engines and fitted with the bulged bomb bay doors. So it became a redundant project, and although the RAF wrote specification B.4/42 around it, the DH 102 was a company funded private venture that was killed off by the aircraft that it was intended to supplement and ultimately replace, the Mosquito, as DH did with it most of what they hoped to do with the DH 102.

However, I have read that the DH 102 did heavily influence the Hornet design-wise. Granted, not much is known about it (most of what I know is from that DH Hornet book), but it does look like a slightly enlarged Mosquito (slightly longer and with a wider wing span), and it also, based on the model shown in the book, looks like a rather engorged Hornet.

Anyone know the specifics on the DH 102, what it may’ve looked like and how did it differ from the Mosquito it was developed from and how it may’ve influenced the Hornet? Also, for anyone who may know or may have a guess, I also recall seeing some Vampire influence in the wing plan design, and that also influenced the laminar flow wing on the Hornet. Could that have also made a showing on the DH 102’s proposals?

Well, I did my research after reading though the DH Hornet recollections section, and I found the info I wanted to discuss regarding the “Hornet vs Mosquito” aileron question. This was found in the recollections that John Wimpenny submitted about the design of the Hornet’s control surfaces, Wimpenny being an assistant to Eric Bishop during the Hornet’s design.

John said that the Hornet used ailerons that had had a blunt chord near the trailing edges and piano hinges (?) as opposed to the Mosquito’s set back hinges and more tapered trailing edges. This was an ideal that seemed to be good in theory for drag reduction, but in Wimpenny’s opinion, didn’t work out as well as planned because of inconsistencies in manufacturing. Each aileron ended up being slightly different to the other, with the result that if one was changed out, the aircraft’s handling and characteristics changed slightly as well depending on the aileron’s surface.

He also felt that the the DH Mosquito’s set back hinges allowed for more fluid and consistent feel to the pilots. But the issue he seemed to have was turbulence caused by the inconsistencies with the ailerons and that such items seemed to actually hinder the DH Hornet in the fight against compressibility, which likely reduced the roll rate and, at least to an extent, turning radius because of of the adverse effects that the ailerons had in their function.

It should be noted that the DH Vampire used similar ailerons without major issues until the last 20-30mph of it’s speed range, but with the DH Vampire, de Havilland not only introduced power-boosted controls, but reverted, at least partially, to the Mosquito set back hinges and tapered ailerons.

It seems that Wimpenny’s reservations about the Hornet seemed to be about the hinges and contours/taper of the ailerons and that, though a good idea in theory, didn’t bear the fruit with the Hornet that such changes did with say late Griffon-engined Spitfires, which the Spitfire had roll rate issues caused in part by compressibility which were largely cured by using a stronger wing torsion box (strengthened main and rear spars) and the new RAE ailerons. And in the case of the Hornet, due to the turbulence due to the inconsistent contours of the ailerons on the DH103, compressibility really reared it’s head and tended to reduce roll response dramatically, and probably didn’t do the Hornet’s turning performance any favors, either.

Power boosted controls helped solve the issue for the Venom, but so did “goin’ back to the future” by using what worked in the past with the Mosquito. Could the changes that Wimpenny be suggesting have resolved or at least remedied to an extent those issues he mentioned? That being said, knowing that, he was still impressed with how most of the pilots that flew it liked the Hornet. Maybe an instance of making a great plane even better?

Edit: @dcollins103: This post is actually what I was originally asking about. I wasn’t able to read your post prior to this one going up, as I was probably typing it while also trying to look up RAE’s name for the aileron type that Wimpenny used in his recollections submission. I will grant this that most of the Hornet’s pilots were former single engined fighter pilots (mostly having flown Mustangs, Spitfires and Tempests) who were quick to find fault relative to their former mounts–fighter pilots, like race drivers, after all, are never seemingly satisfied.

But the Hornet needed excellent agility to take on it’s intended foes of the Imperial Japanese Navy and IJAAF, and I’m willing to bet that in actual combat conditions that the Hornet likely, for it’s issues, could’ve likely held it’s own, but we’ll never know, because by V-J day, too few were in RAF hands to be sent out to the Pacific. And it must be remembered that most of these issues came to light in the fall of 1945 (in other words, post-war peace time) when an aircraft can be examined more thoroughly. And to test it against allied fighters (which were in general superior to most axis aircraft) can cloud the results, because an aircraft’s effectiveness relative to the enemy is what matters most.

I apologize for any confusion, but to get back to my original question, could the suggestions that Wimpenny made about the Hornet have changed anything and make a great aircraft even better?

And sorry for the long post–I only caught your message after I posted this originally.

That can be an interesting point of discussion, because the P-38 and the P-61 had the engine nacelles extended to form the tail booms that retained the rudders and tail plane, which given what you’ve said, probably helped those aircraft in that respect, namely the P-38. And like the Hornet, the P-38 used handed engines.

If the engine nacelles caused some areo issues, other than extending them, was there much else that could be done?

And did this buffeting have anything to do with the seeming lack of agility that the Hornet had when it was tested after WWII, or is it simply a deal of it being a twin engined aircraft–after all, the P-38, especially late versions, could out turn and out roll Me-109s and FW-190s, in spite of the P-38 being larger and having a high wing loading. And the Hornet, of course, was about the same size and the same type of long range aircraft.

I think that I’m getting the gist that a lot of this might have to do with the Hornet having unforeseen compressibility issues, and if the P-38 had changes to it’s control surface hinges in addition to power boosting of major controls to battle comprehensibility, maybe answer lies in what could’ve been done to try and control the issue. I’ll try and brush up on the DH engineer’s comments on the aileron tech, and I’ll get back with a summary of his comments, but it seems that what he may’ve said may’ve been issues with compressibility.

@pagen01: That could be part of the reason why the P-38 used powered ailerons, as they were fitted to a lot of -J and all -L and -M models, and they were the fastest of the Lightning family. However, almost all P-38s were fitted with dive recovery flaps (and on the Mosquito, the radiator outlet flaps could serve as such) to prevent that, and I read online, trying to find the info that David had lead me to, that the powered ailerons also helped give the later P-38s a noted reduction in turning radius, and, above all, a massively improved roll rate.

@dcollins103: If I remember correctly, the issues with the hinges were part function and feel, and part aerodynamic. The Vampire used the type of hinge that the Hornet used, and it worked as hoped. The RAF endorsed the use of that hinge to reduce drag as it didn’t protrude on the upper surface of the wing. But the Vampire had an all-metal wing, as did the P-38. However, the Hornet’s wing was part metal (wing main spars, some stringers and ribs, and underside skin), and wood (parts of the main spars, upper skin, and some stringers/ribs). It seems that the metal Vampire wing was more receptive to the RAF’s hinge than the Hornet’s mixed construction wing.

On the aero side of the equation, the protruding (but well faired) Mosquito hinge did likely cause a marginal amount of drag, but probably not enough to make a huge difference (probably less than the Sea Hornet’s wing fold hinges, which likely wasn’t much, either). I do remember, possibly rightfully or wrongfully, that there was an airflow issue over the ailerons that caused issues with buffeting/turbulence that hindered their effectiveness. This may’ve been fixed at a later stage, but we must also remember that most Hornet pilots trained on Mosquitoes (as most Hornet pilots were former Spitfire, Mustang, or Tempest pilots), and I do seem to remember from the book that one pilot did remark that the ailerons did feel different on the stick, and that the Mosquitoes did feel better as far as ease of use and harmony.

I do wonder if that wing/radiator outlet issue played a bigger role in the Hornet’s handling/maneuverability issues, especially early in it’s life, than the aileron issues mentioned. Did the Mosquito have this issue? If not, then it could be a design issue, as both the Hornet and Mosquito radiators did use the zero drag/Meredith effect to generate thrust to offset any cooling drag, and it seems that the Hornet’s radiator fairings extended back further relative to those of the Mosquito, ironically because the Hornet’s radiators had to handle more cooling, as water, oil, and supercharger intercooler were cooled by one main matrix per wing.

Of course, such a thing is of an academic interest now, as this was never fully cured in the Hornet’s decade long RAF career, and with the Vampire and Meteor becoming the RAF’s main fighter element, the Hornet’s issues were of secondary importance, though if the war against Japan wore on, it would’ve become a major importance.

And one more question: In the British Fighter since 1912, the Hornet was quoted as having a roll-rate of 72 degrees per second (highest recorded by a twin-engined piston fighter), though this was most likely achieved by either a prototype, or an early production aircraft partially loaded. For comparison, the Martin Baker MB5 had a roll-rate of 94 deg/second, one of the highest figures for any piston engined fighter. Could this simply be a thing of production aircraft usually being heavier that certain measures didn’t fully compensate for that scenario?

@john txic: DH Hornet and Sea Hornet: de Havilland’s Ultimate Piston-Engined Fighter, co authored by Mr. Collins, of course :). Great source of info and rare photos and technical details.

So it seems that the Hornet was compromised mainly by how quick the time frame that the RAF’s request was, in spite of it being designed as a private venture in 1942, months before the RAF gave official recognition to the program. I can understand the urgency, as the RAF probably wanted the Hornet in service by X-day, the planned Allied invasion of Japan (which thankfully never happened), but what I don’t understand is why the RAF didn’t see the Hornet as useful when it was offered, considering that the USAAF had the P-38, which nearly entered RAF service, but the USAAF, GE and Allison/GM wouldn’t sell them the turbocharged engines because it was a secret technology at the time, and as the Allison V-1710 had a single stage supercharger, the only alternative was to re-engine with Merlins, which GM protested against when the USAAF and Lockheed though it was a good idea, but that’s a story all to and in itself.

I haven’t read the book in detail yet, but you do mention that the Hornet was a bit of a compromised design due to areo issues, at least compared to the Mosquito or perhaps the Vampire, which was developed over a period of several years before they entered service. And the Vampire is often cited as one of the most agile jet fighters ever made, being lightly loaded as far as wing loading and being fairly small.

I do wonder what aero conditions restricted the Hornet’s maneuverability and handling, considering that the only aero stuff I know of is from auto racing, and even though that’s been influenced by aircraft design, it still two different worlds, and I’m no aerodynamicist or engineer.

But it was mentioned that even allowing for it’s twin engined design, that only a certain amount of roll was truly useful, but it was believed that the Hornet, design issue not withstanding, could have a useful rate of turn and roll as a dogfighter, but it seems that some issues didn’t allow for the minor issues preventing that from being fully fulfilled to fully be ironed out. And with the Vampire and Meteor on the way, the Hornet’s issues were basically of academic interest.

And on a point of the F-82, in additon to power boosting of it’s controls, it wings were highly stressed to handle a higher wing loading (owning to a fairly high aspect ratio and a wing area of about 80% of two P-51 wings) and it’s expect asymmetric crew layout, along with a considerable ordinance payload and internal fuel housing. It also had considerable aileron travel, just like the P-51H, of about 15 degrees. But then again, Ed Schumnd had designed the Twin Mustang as a private venture (like with the P-51 itself) and most of the design work was done before Hap Arnold saw the plans and approved it for a service request. And it seems that Schumnd was afforded more luxuries with achieving the aim of a twin engined fighter than DH’s Eric Bishop and his team had, and met less organizational inaction/meddling than DH did.

So I guess the big question is that if the RAF had approved the DH103 private venture design to an official RAF specification when DH first offered it up, would most of those issues have been resolved before the RAF tested it in detail in the peace of 1945 (which also revealed the stability issues that any Hornet fan knows about)?

I promise that I’ll read on in more detail, but thanks for your help on the subject.