Apophenia's Offerings

[GTX_Admin]

Da, very refreshing! Currently, GLONASS coverage is excellent (outages of between one-to-three months being well within acceptable productivity quota goals).

You been selling 'favours' to the commandant again comrade?  That's obviously the only way you would get such favourable treatment.

[Tophe]

Beautiful!

[apophenia]

Thanks folks.

Evan: I hadn't thought of going further with this but now ... 

You been selling 'favours' to the commandant again comrade?  That's obviously the only way you would get such favourable treatment.

If we are going to meet this collectives announced gross production quotas, all must suffer for their art. BTW, I've given him your number 

[apophenia]

Bell Aircraft also received a DB 601N for study. This engine was incorporated into a new private venture fighter design -- the Bell Model 18. With a typically radial approach, Bell adopted a tricycle landing gear for their Model 18. This decision proved to be Bell's undoing.

On its maiden flight, the prototype Model 18 was put through its paces over Lake Ontario. The machine handled very well and top speed in the lightly-loaded (and unarmoured) aircraft was above expectations. However, on approach to Buffalo, the nose gear failed to lock in the down position. As the fighter alighted the nose gear folded and the Model 18 pitched onto its nose. In the ensuing crash landing, the fighter's back was broken and its DB 601N's propeller reduction gear was torn from the aircraft.

The Air Corps took the fate of the prototype as a warning and no further Model 18 fighters were ordered.

(Top) The sole Model 18 prototype as rolled out at Bell Aircraft's Buffalo plant. Despite its jaunty tail stripes, the Bell Model 18 was not an Air Corps aircraft.

(Bottom) The prototype Model 18 as it appeared on its one-and-only flight. Note that the belly radiator is only partly retracted. This radiator was never fully-retracted in flight.

[apophenia]

Another US firm which received captured Daimler-Benz engines for study was the Republic Aviation Corporation. Republic had drafted a Merlin-engined fighter - the AP-10 - to Air Corps circular proposal 39-770. After initial interest by the USAAC (as the XP-47/XP-47A), it became apparent that this design was already obsolete. Accordingly, work on the XP-47/XP-47A was terminated in September 1940.

Republic's Alexander Kartveli shifted his design focus onto a larger, radial-engined AP-10, the turbo-supercharged XP-47B Thunderbolt. Thus, Republic was not in a position to offer the Army a new DB-601-powered fighter design. Republic's predecessor, Seversky Aircraft had developed a liquid-cooled derivative of its P-35 fighter - the AP-3. In the absence of a suitable powerplant, the AP-3 had stalled. However, it was now obvious that such an adaptation could serve as an effective DB 601 testbed. Accordingly, the prototype AP-7A was converted to take a captured German engine as the AP-3D.

The DB 601Aa powerplant, taken from a downed He 111P bomber, was not ideal for a fighter application but the AP-3D allowed Republic to gain experience with this liquid-cooled engine. Testing showed that the AP-3D left much to be desired. Balance was poor and top speed was well below expectations. NACA wind tunnel testing would later show that the main fault lay with the contouring of the AP-3D's ventral radiator bath. However, by that time, the one-off AP-3D had nose-over while taxiing on soft ground, damaging its DB 601Aa beyond economical repair.

(Top) The prototype Republic AP-3D upon roll-out at Farmingdale, NY. Prior to the AP-3D's first flight, registration were added and, at some later point, the Republic logo appeared on the fin.

Republic had already moved on. Work was well underway on the XP-47B Thunderbolt. It was decided to develop a smaller, Hudson V-2070-engined fighter using as many P-47B airframe components as was feasible. [1]  The result was the AP-11 which incorporated P-47B tail surfaces and Thunderbolt wing panels joined on the centreline rather than to the fuselage sides. Compared with the P-47B, the AP-11 fuselage was narrower and somewhat shorter. It also lacked the P-47B's deep belly since the AP-11 had no turbosupercharger fitted.

Dubbed Thunderbird, [2] the AP-11 was accepted into USAAF service as the P-44B - a designation 'recycled' from the P-44 Warrior which had been cancelled in September 1940. The original Air Corps order for 80 P-44 was transferred to an equivalent number of P-44B-1RE fighters (which would include the prototype XP-44B). Large follow-on orders resulted in Thunderbird production by both Republic and Curtiss -- P-44Ds and P-44Fs built by the latter ultimately replacing production of Curtiss' own P-40 fighter.

(Bottom) A P-44D-3CU Thunderbird - the Curtiss-built equivalent of Republic's P-44B - in USAAF service.

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[1] To leave Kartveli free to perfect the XP-47N, this work was undertaken by former collegue Alexander Gregor who had arrived back from CCF in early 1940.

[2] Originally, 'Thunderclap' was proposed for the P-44B. That name was rejected due to its slang connotations.

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[Empty Handed]

There's something unnatural/disconcerting to me about the inverted-vee P-40 (great work nonetheless) but the Thunderbird is very shapely! Great stuff. Could we have a bubble-top or two please? _(sorry)

[GTX_Admin]

I like the look of the P-44D-3CU Thunderbird

[apophenia]

Cheers! EH: You bet, I'll have a go at some 'bubble-tops'.

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The USAAF received other submissions for other fighters to be powered by the Hudson V-2070 'Hornet' engine. One set of submissions from an unexpected source came from North American Aviation.

For study purposes, North American had received a Messerschmitt Bf-109E-1 damaged in a crash landing. NAA's primary goal was to glean what it could from contemporary construction techniques employed by German industry. Although the Bf-109E-1 was far from airworthy, NAA was able to study Messerschmitt's unique fuselage contruction approach. Other than crushed radiator housings, the German fighter's wings were completely intact.

A contract was received from the USAAC to fit these wings (and the Messerschmitt's main undercarriage) to a modified North American BC-1A trainer. The object was the development of a more useful combat trainer with built-in wing armament and great speed. NAA constructed a new BC-1 centre section which only extended to the fuselage sides. The Bf-109 wings bolted directly onto this truncate centre section as did the Messerschmitt's main undercarriage legs.

(Top) North American BC-1M combat trainer conversion prior to delivery to Wright Field.

The resulting North American BC-1M was delivered to Wright Field for evaluation. A noticeable increase in level speed was noted but at the cost of inferior manoeuvrability and low-speed handing. In the assessment, NAA was said to have met the goals of the conversion exercise. But, with its 'trickier' handling, the BC-1M was judged to have little utility as a future combat trainer.

It the meantime, NAA surprised the USAAF with an unsolicited submission for a new V-2070-powered fighter. This Ed Schmued design was heavily influenced by the Bf-109E and several variants were offered. In its most basic form, the fighter was a near-direct copy of the Messerschmitt. Notable changes included a new canopy on a slightly enlarged cockpit. The cockpit was also moved aft to allow cowl-mounted, synchronized Browning .50-calibre machine guns. A completely new tailplane was also introduced. [1]

The second proposed variant replaced Messerschmitt's twin wing-mounted radiators with a new belly-mounted radiator bath. In variant 2A, armament was to be 1 x 20 mm Madsen and 2 x cowl-mounted .50-calibres. In variant 2B, (Centre) NAA proposed substituting a 20 mm Oerlikon for the Madsen and retaining the Bf-109's twin Oerlikon wing guns.

The third proposed variant (Bottom) introduced an entirely new laminar-flow wing. [2] This broader-chord wing necessitated a fuselage 'stretch' but allowed the use of a new wide-track main undercarriage (a retractable tailwheel was also adopted). Armament for the third variant was to comprise the 20mm Madsen motor cannon and 4 x wing-mounted .50-calibre guns. In this variant, the cowl-mounted Brownings were eliminated.

For an unsolicited submission, the North American fighter proposal generated a lot of discussion amongst planners. Were performance estimates realized, the NAA fighter (particularly the third variant) would have a considerable edge over the selected Republic P-44B Thunderbird. However, North American was a maker of basic trainers with no prior experience in fighter design. Accordingly, NAA's fighter submission was declined and the firm encouraged to focus on trainer production and on perfecting its new medium bomber design.

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[1] The Bf-109E-1 provided to NAA had nosed over after belly landing. Both the tail surfaces and the cockpit canopy were heavily damaged in the ensuing crash.

[2] This laminar-flow wing was based on Curtiss XP-46 data provided to NAA by the NACA.

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[Tophe]

Beautiful P-51/Bf-109 mixes, thanks!

[Hardrada55]

Reminds me of designs I've seen of the SAAB L-23 (J-23). 

[Tophe]

Apophenia, you made me dream of a whole family, thanks again!

[apophenia]

Tophe: Thanks for those! I particularly like your Apo-83E  :)

Hardrada55: I didn't have Projekt L 23 in mind when I did the profiles. But, you're right, the laminar-flow one really does look like that Saab concept!
 - http://www.x-plane.org/home/urf/aviation/text/saabcanc/
 - http://i.imgur.com/wB5jruC.png

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Now, a pair of 'bubble-top' P-44 Thunderbirds for Empty Handed ...

(Top) 'Touch of Texas' was a P-44E-1RE, the 'bubble-top' development of Republic's 'razor-back' P-44B-4RE. These early-production 'bubble-tops' were virtually identical to the XP-44E conversion prototype.

Like the P-44B-4 before it, the P-44E-1RE was a 'cannon-fighter', armed with a 20 mm motor-cannon and four wing-mounted .50-cal Brownings. '2Z*M' was also later fitted with wing-racks for bombs. [1]

'Touch of Texas' is finished in the standard factory scheme of Olive Drab upper surfaces and Neutral Gray undersides.

(Bottom) 'Ole Cock' was a P-44F-2CU Thunderbird, the Curtiss-built equivalent of Republic's P-44E. A 'gun-fighter', the P-44F was armed with six .50-cal Brownings - 4 x wing-mounted machine guns and 2 x synchronized cowl guns.

'HV*A' wears the standard paint scheme but Medium Green 42 has been used to break up the Olive Drab (and patch over badly-worn paint work). Newly applied are 'Invasion Stripes' for recognition during Operation Overlord.

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[1] These retro-fitted wing-racks were not plumbed so only P-44E-3s and later could carry drop tanks.

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[GTX_Admin]

Interesting look.

[Tophe]

  (lovely P-44-DB601-bubble)

[Acree]

I really like the P-44 series, Apophenia, especially the bubble-tops. 

[AXOR]

Certainly looks interesting with that engine.

[Empty Handed]

The Bubbletops look fantastic! Thanks.  :)

[apophenia]

The Army Air Force was not the only arm with an interest in the Hudson V-2070 'Hornet'. [1] The US Navy also saw potential in this V-12 engine.

The Bureau of Aeronautics issued a requirement for studies of fast-climbing fleet interceptors. Grumman chose not to respond to this requirement but submissions were received from new-comer McDonnell and well-established Vought-Sikorsky as well as Brewster and former USN fighter supplier, Curtiss.

Since 1939, McDonnell had been working up an advanced Army fighter with a centrally-mounted engine driving twin propellers through extension shafts. For the Army fighter, pusher props were proposed. For the BuAer submission, a similar shipboard interceptor was conceived. Several arrangements were drafted and, in consultation with BuAer officials, an all-over smaller fighter was designed with twin, shaft-driven tractor propellers.

(Top) Late 1941, McDonnell engineering mockup for its proposed V-2070-powered naval interceptor.

Vought-Sikorsky's submission was much more conventional. Rex Beisel and staff drafted a new fighter that combined features of Vought's XF4U-1 Corsair and the German Bf-109. The result was a smaller and much lighter naval interceptor concept. The rear fuselage of the production F4U was to be used almost unchanged but the fighter's layout was much changed from the Corsair.

In place of the Corsair's inverted-gull, an 'unbent' wing was employed. This wing shared the Corsair wing's planform but, structurally, owed more to the Messerschmitt. So too did the Vought's outwards-retracting main undercarriage. The Hudson engine was conventionally mounted but Vought was proposing a heavier motor-cannon armament. Two additional .50-calibre machine guns would be wing-mounted to fire outside of the propeller arc.

(Bottom) Vought-Sikorsky naval interceptor concept. Note the twin coolant radiators let into the sides of the rear fuselage (to avoid radiator baths 'digging in' when belly-landing at sea).

To the BuAer, neither the McDonnell nor the Vought interceptor concepts warranted further development. The Vought submission was seen as too big for its engine and likely too heavy to perform well. Worse, the design relied upon a variant of V-2070 that could accommodate a new cannon design (of 25-to-30 mm) -- neither of which existed at that point.

McDonnell was congratulated for its effort but the resulting design was seen as excessively complex while extension-shafts and gearing were likely to push all-up weight beyond naval shipboard fighter limits. The BuAer also had concerns about shipboard operation of an aircraft fitted with a tricycle undercarriage.

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[1] Since 'Hornet' was already associated a Pratt & Whitney radial engine, Hudson's appellation for its V-2070 was never accepted as a Service type name.

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[Tophe]

Wow! Marvelous!

[apophenia]

The Curtiss submission for a US Navy Hudson V-2070-powered interceptor was simply a navalized version of the firm's P-40B. This concept was quickly rejected by the BuAer.

Brewster's earliest submission had been derived from its twin-boomed Model 33 studies. The BuAer acknowledged the cleverness of this design - a revised, forward-placed cockpit had a smooth, Airacuda-like canopy and its twin booms folded forward over the central nacelle for maximum carrier-storage compactness. The BuAer was less glowing in its assessment of Brewster performance estimates for the Model 33H.

(Top) The Brewster Model 33DB concept in its forward-cockpit, 4-machine gun armed form.

(Centre) Twin tails were adopted to facilitate onboard folding for stowage.

Once the tailbooms were folded, airframe height could also be lessened by compressing the nose wheel leg. The object was even more compact stowage below decks. The BuAer was impressed with the originality of Brewster's Model 33H but concluded that airframe weight, as with the McDonnell submission would be excessive.

Ironically, the most promising Brewster submission had been included only for comparison purposes with the firm's preferred Model 33H. The Brewster Model 41 was a much more conventional design derived, in part, from Brewster's in-service F2A-3 airframe. Like the Vought-Sikorsky submission, Brewster based its wing upon that of the F2A-3 but revised the structure to take a narrow-track undercarriage much like that of the Bf-109.

The BuAer concluded that the Brewster Model 41 represented a low-risk development which would put a V-2070-powered interceptor aboard US Navy aircraft carriers in the shortest amount of time. What the BuAer could not anticipate was the muddled management at Brewster and the resulting production delivery delays for its designs. Unfortunately, the Model 41 was no exception.

(Bottom) Prototype Brewster XF3A-1 Brigand delivered for testing at NAS Pax River.

Brewster's final fighter design never saw combat with the US Navy. Deliveries were glacially slow and the USN quickly lost interest in the project. All F3A-1 and F3A-2 Brigands were redirected to US Marine Corps squadrons. The Brigands served the USMC well but numbers were never large and the production run was short. By mid-1944, all Marine Brigands had been retired from active service.

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[AXOR]

I definitely like the Brewster 33 DB,it has a Schelde vibe and I like it alot,Brigand is also interesting...lovely new profiles  :)

[raafif]

love those inverted engines !  I hope the US did better than Japan with building the DB designs

[elmayerle]

Beautiful stuff!!!  So, did Bell offer designs with the Hudson engine?

BTW, I think the Vought-Sikorsky design might still need the inverted gull wing for propeller clearance with the ground or deck.  Too, I could see a development of that one using leading edge radiators to reduce drag.

Raafif, since the Italians didn't have any problems building the DB designs, I would reckon the US wouldn't.  ISTR a claim that the Japanese did have problems because they reversed the engine rotation to work with the propellers they had.

[Tophe]

  I love your Brewster twin-boomer (with a new engine)...

[apophenia]

Thanks folks!

Alex: Well spotted! The de Schelde S.21 was exactly what I was going for ... with all due apologies to Theo Slot 

Evan: Yep, Bell offered its prototype Model 18 fighter ... and any similarity to the Me 309 is purely coincidental 
 -- http://beyondthesprues.com/Forum/index.php?topic=351.msg126122#msg126122

Agreed on the Vought-Sikorsky concept. Overall, the airframe would've just been too big for the engine. US DB 603, perhaps? 

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And now, the final installment on US Hudson V-2070-powered fighters ...

Lockheed had made several attempts to develop a twin-engined fighter under various Model 22 concepts. It was the radial-engined, twin-boomed Model 24 which finally received a contract -- but in the photo-reconnaissance role as the F-4A Lightning. One F-4A airframe was held back for conversion from bulky radials to more streamlined Hudson V-2070 V-12s. Fitted with nose-mounted machine guns, this aircraft was redesignated XP-38 Lightning. [1]

(Top) Lockheed XP-38 Lightning prototype conversion. Note boom-mounted radiators for V-2070 engines.

The production P-38A fighter achieved some success operating from bases in Iceland as a long-range interceptor against German Fw 200 raiders. But, the P-38A was a low-rate production aircraft -- being neither fast enough nor manoeuvrable enough to operate against the best enemy fighters.

Lockheed, together with NACA, had studied methods for improving the Model 24's aerodynamics. The most promising was a new, underslung central fuselage pod. (Centre) Other, non-aerodynamic benefits of this revised fuselage arrangement was greater internal fuel tankage (all close to the aircraft's c/g) and a shorter (and therefore lighter) nose gear. The prototype XP-38 was fitted with such a nacelle as the XP-38C. [2]

(Bottom) Sole prototype Lockheed XP-38C conversion. Note nose-mounted machine guns.

As a fighter, the XP-38C Lightning left much to be desired. It was faster and longer-ranged than the P-38A but visibility from the cockpit was poor in all directions other than directly in front. However, this lack of all-around visibility was not a major disadvantage for the photo-recon role. Accordingly, the XP-38C was disarmed and fitted with camera equipment as the prototype XF-5A Lightning -- the first of many high-speed photo-reconnaissance F-5As.

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[1] For the production P-38, each V-2070 engine was also to be fitted with a 20 mm motor-cannon.

[2] The XP-38B had been a production P-38A employed as an armaments trials airframe.

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