zanenobbs
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Thank you for this reference! We strive for accuracy and this will defintely help!
Straight-wing F-86 Prototype
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Same photo appears in the Hatchette bookazine along with a photo of a desktop model and a 3-view drawing of the design. Both the mockup photo and the drawing are reproduced in a good and useful size.
So... 2024 or so?
zanenobbs
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That's a great build!
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Instead off open new topic,we can discuss this here;
In late 1944,USAF issued a design request for medium range day fighter that also cope with
the escort fighter and fighter-bomber missions,and NAA submitted RD-1265,a developed
version of the FJ-1,and my question is ; was there any competitors to it ?.
In late 1944,USAF issued a design request for medium range day fighter that also cope with
the escort fighter and fighter-bomber missions,and NAA submitted RD-1265,a developed
version of the FJ-1,and my question is ; was there any competitors to it ?.
On 11 September, 1944 the USAAF issued a General Operational Requirement (GOR) calling for a day fighter with a top speed in excess of 600 mph (965 kph), 850 mile (1,368 km) range, 8x0.50 cal M3 or 6x0.60 cal heavy machine guns.
To meet the specification, eight days after the publication of the GOR the firm Republic Aviation Corporation proposed the AP-23 design, with 611 mph estimated top speed.
In 4 October, 1944 the North American design team envisaged the study of the NA-140 jet fighter, with nose air intake, wings and tail surfaces similar to those FJ-1.
To avoid compressibility shock, the NA-140 had laminar-flow straight wings with 10 per cent thickness/chord ratio and a very slim fuselage with a high fineness ratio.
The wings have ‘fence’ airbrakes in the upper and lower surfaces, folding system and 2x170 gal (644 lt) wingtips fuel tanks.
To save drag is designed one curved windshield and one teardrop canopy with 64 cm (25 in) width only, 17 cm less than that of the P-51 D.
The critical Mach number (the speed at which it can fly without encountering control problems due to compressibility) of the NA-140 airframe was 0.9, higher than 0.8 of the Lockheed XP-80 and 0.76 of the P-51 D.
The proposed engine was one General Electric GE-2 (TG-180) axial flow turbojet rated at 1,730 kgf (3,820 lbf) static thrust, circular air intake and ‘S’ curved air duct to pass under the cockpit.
NA-140 (4 October, 1944) technical data
Wingspan: 12.17 m (39 ft-11 inch), folded wingspan: 5.39 m (17 ft-8.5 in), length: 11.53 m (37 ft-10 in), height: 4.65 m (15 ft-3 in), estimated max speed: 925 kph, (575 mph), armament: six 0.50 cal MG 53-2 heavy machine guns.
On November 1944 the GOR was modified calling for six 0.50 cal only, that same month the USAAF ordered three Republic AP-23 prototypes under the designation XP-84.
North American improved the original design of the NA-140 to gain some speed, in the proposed on 15 August 1945 version the weight and dimensions of the aircraft had been reduced, but aerodynamic tests carried out with wind tunnel models only indicated 582 mph top speed.
The proposed airplane had pressurised cockpit, boosted controls and AN/APG-5 radar rangefinder, the antenna was mounted in the extreme nose and it was necessary to design a new air intake, with an oval section, for the Allison J 35-A-15 turbojet with 250 lbs static thrust more than the J 35 GE-2.
NA-140 (15 August, 1945 project) technical data
Wingspan: 11.64 m (38.2 ft), length: 10.82 m (35.2 ft), height: 4.02 m (13.2 ft), wing surface: 23 sq. m (255.3 sq. ft), estimated max speed: 937 kph, (582 mph), estimated max weight: 5,210 kg (11,500 lbs), estimated ceiling: 14,177 m (46,500 ft), armament: six 0.50 cal M3 heavy machine guns, engine: one Allison J 35 A-15 axial flow turbojet rated at 4,000 lbs (1,812 kgf) static thrust.
On 18 May, 1945 the USAAF ordered two prototypes of the NA-140, under the designation XP-86. The mock-up was approved on 20 June, 1945, four months after the XP-84 mock-up.
The North American officials knew that the NA-140 programme would be cancelled by the lack of speed, but there were only two possible solutions: reduce drag or use to more powerful turbojet. Using the materials available at the time is considered physically impossible to reduce wing thickness without dangerously degrading its structural strength and the new Allison turbojet would take too long to become available.
On 28 February, 1946 the Republic XP-84 prototype was flown powered by one J 35-GE-7 rated at 3,750 lbf (1,700 kgf) static thrust, a maximum speed of 573 mph (922 kph) was attained.
On 29 April, 1945 a company of U.S. infantry occupied the Messerschmitt research centre at Oberammergau and capturing the Messerschmitt P.1101 prototype, an experimental fighter with swept-back wings and tail surfaces, designed to fly at 612 mph (985 kph).
The P.1101 was powered by one Heinkel-Hirth HeS 011 turbojet rated at 2,649 lbf (1,200 kgf) static thrust only.
Fortunately for North American the German research data on swept-wing flight was available in July 1945.
On 14 September, 1945, wind tunnel test were performed with a 1/23 rd NA-140 scale model, with 35 degrees wings swept.
These trials were extremely promising and the USAAF approved the modification, entitled RD-1369, in 1 November, 1945.
On 23 April, 1946 North American proposed a new design that could use two new types of swept-wings but retained the fuselage and tail surfaces from the previous version.
The 5AR type had 37 degrees swept, 5 aspect ratio and 37.07 ft (11.3 m) wing span to provide for better stability.
The 6AR type had 39 degrees swept, 6 aspect ratio and 40.8 ft (12.44 m) wing span to provide for better range.
At that time there were doubts about the ideal configuration because the wings of the Messerschmitt P.1101 had been built with a variable swept that could be adjusted, in the ground, between 35 and 45 degrees. The prototype had been captured before performing its first flight, which was planned in June 1945.
The data captured from the Germans were only theoretical estimates.
In 15 October, 1946 the NA-140 had 36 degrees swept-wings, 38 degrees swept-tail plane, 40 degrees swept-tailfin and circular air intake.
The wings were fitted with automatic slats in the 90 per cent of the leading edge to provide stability at low speeds.
NA-140 (15 October, 1946 project) technical data
Wingspan: 11.34 m (37.2 ft), length: 11.44 m (37.54 ft), height: 4.4 m (14.49 ft), estimated max speed: 1,046 kph, (650 mph), armament: six 0.50 cal M3 heavy machine guns, engine: one Chevrolet J 35-C-3 axial flow turbojet rated at 4,000 lbs (1,812 kgf) static thrust.
The prototype XP-86, with 35.2 degrees wing swept, was rolled out on August 8, 1947 performing its first flight in 1 October, 1947.
The wing thickness/chord ratio was optimised at 11 per cent inboard and 10 per cent at the wing tips, the airbrakes were moved to the rear fuselage sides and the canopy width was enlarged 30 cm (11.7 in) to allow the ejection seat operation.
On 26 April, 1948 the XP-86 went supersonic, in a shallow dive, powered by one J 47-GE-3 axial flow turbojet rated at 5,200 lbf (2,356 kgf) static thrust.
XP-86 (1 October, 1947) technical data
Wingspan: 11.44 m (37.54 ft), length: 11.31 m (37.12 ft), height: 4.5 m (14.79 ft), wing surface: 25.45 sq. m (283 sq. ft), max speed: 1,020 kph, (634 mph), max weight: 7,446 kg (16,437 lbs), ceiling: 13,260 m (43,500 ft), armament: six 0.50 cal M3 heavy machine guns, engine: one Chevrolet J 35-C-3 axial flow turbojet rated at 4,000 lbs (1,812 kgf) static thrust.
To meet the specification, eight days after the publication of the GOR the firm Republic Aviation Corporation proposed the AP-23 design, with 611 mph estimated top speed.
In 4 October, 1944 the North American design team envisaged the study of the NA-140 jet fighter, with nose air intake, wings and tail surfaces similar to those FJ-1.
To avoid compressibility shock, the NA-140 had laminar-flow straight wings with 10 per cent thickness/chord ratio and a very slim fuselage with a high fineness ratio.
The wings have ‘fence’ airbrakes in the upper and lower surfaces, folding system and 2x170 gal (644 lt) wingtips fuel tanks.
To save drag is designed one curved windshield and one teardrop canopy with 64 cm (25 in) width only, 17 cm less than that of the P-51 D.
The critical Mach number (the speed at which it can fly without encountering control problems due to compressibility) of the NA-140 airframe was 0.9, higher than 0.8 of the Lockheed XP-80 and 0.76 of the P-51 D.
The proposed engine was one General Electric GE-2 (TG-180) axial flow turbojet rated at 1,730 kgf (3,820 lbf) static thrust, circular air intake and ‘S’ curved air duct to pass under the cockpit.
NA-140 (4 October, 1944) technical data
Wingspan: 12.17 m (39 ft-11 inch), folded wingspan: 5.39 m (17 ft-8.5 in), length: 11.53 m (37 ft-10 in), height: 4.65 m (15 ft-3 in), estimated max speed: 925 kph, (575 mph), armament: six 0.50 cal MG 53-2 heavy machine guns.
On November 1944 the GOR was modified calling for six 0.50 cal only, that same month the USAAF ordered three Republic AP-23 prototypes under the designation XP-84.
North American improved the original design of the NA-140 to gain some speed, in the proposed on 15 August 1945 version the weight and dimensions of the aircraft had been reduced, but aerodynamic tests carried out with wind tunnel models only indicated 582 mph top speed.
The proposed airplane had pressurised cockpit, boosted controls and AN/APG-5 radar rangefinder, the antenna was mounted in the extreme nose and it was necessary to design a new air intake, with an oval section, for the Allison J 35-A-15 turbojet with 250 lbs static thrust more than the J 35 GE-2.
NA-140 (15 August, 1945 project) technical data
Wingspan: 11.64 m (38.2 ft), length: 10.82 m (35.2 ft), height: 4.02 m (13.2 ft), wing surface: 23 sq. m (255.3 sq. ft), estimated max speed: 937 kph, (582 mph), estimated max weight: 5,210 kg (11,500 lbs), estimated ceiling: 14,177 m (46,500 ft), armament: six 0.50 cal M3 heavy machine guns, engine: one Allison J 35 A-15 axial flow turbojet rated at 4,000 lbs (1,812 kgf) static thrust.
On 18 May, 1945 the USAAF ordered two prototypes of the NA-140, under the designation XP-86. The mock-up was approved on 20 June, 1945, four months after the XP-84 mock-up.
The North American officials knew that the NA-140 programme would be cancelled by the lack of speed, but there were only two possible solutions: reduce drag or use to more powerful turbojet. Using the materials available at the time is considered physically impossible to reduce wing thickness without dangerously degrading its structural strength and the new Allison turbojet would take too long to become available.
On 28 February, 1946 the Republic XP-84 prototype was flown powered by one J 35-GE-7 rated at 3,750 lbf (1,700 kgf) static thrust, a maximum speed of 573 mph (922 kph) was attained.
On 29 April, 1945 a company of U.S. infantry occupied the Messerschmitt research centre at Oberammergau and capturing the Messerschmitt P.1101 prototype, an experimental fighter with swept-back wings and tail surfaces, designed to fly at 612 mph (985 kph).
The P.1101 was powered by one Heinkel-Hirth HeS 011 turbojet rated at 2,649 lbf (1,200 kgf) static thrust only.
Fortunately for North American the German research data on swept-wing flight was available in July 1945.
On 14 September, 1945, wind tunnel test were performed with a 1/23 rd NA-140 scale model, with 35 degrees wings swept.
These trials were extremely promising and the USAAF approved the modification, entitled RD-1369, in 1 November, 1945.
On 23 April, 1946 North American proposed a new design that could use two new types of swept-wings but retained the fuselage and tail surfaces from the previous version.
The 5AR type had 37 degrees swept, 5 aspect ratio and 37.07 ft (11.3 m) wing span to provide for better stability.
The 6AR type had 39 degrees swept, 6 aspect ratio and 40.8 ft (12.44 m) wing span to provide for better range.
At that time there were doubts about the ideal configuration because the wings of the Messerschmitt P.1101 had been built with a variable swept that could be adjusted, in the ground, between 35 and 45 degrees. The prototype had been captured before performing its first flight, which was planned in June 1945.
The data captured from the Germans were only theoretical estimates.
In 15 October, 1946 the NA-140 had 36 degrees swept-wings, 38 degrees swept-tail plane, 40 degrees swept-tailfin and circular air intake.
The wings were fitted with automatic slats in the 90 per cent of the leading edge to provide stability at low speeds.
NA-140 (15 October, 1946 project) technical data
Wingspan: 11.34 m (37.2 ft), length: 11.44 m (37.54 ft), height: 4.4 m (14.49 ft), estimated max speed: 1,046 kph, (650 mph), armament: six 0.50 cal M3 heavy machine guns, engine: one Chevrolet J 35-C-3 axial flow turbojet rated at 4,000 lbs (1,812 kgf) static thrust.
The prototype XP-86, with 35.2 degrees wing swept, was rolled out on August 8, 1947 performing its first flight in 1 October, 1947.
The wing thickness/chord ratio was optimised at 11 per cent inboard and 10 per cent at the wing tips, the airbrakes were moved to the rear fuselage sides and the canopy width was enlarged 30 cm (11.7 in) to allow the ejection seat operation.
On 26 April, 1948 the XP-86 went supersonic, in a shallow dive, powered by one J 47-GE-3 axial flow turbojet rated at 5,200 lbf (2,356 kgf) static thrust.
XP-86 (1 October, 1947) technical data
Wingspan: 11.44 m (37.54 ft), length: 11.31 m (37.12 ft), height: 4.5 m (14.79 ft), wing surface: 25.45 sq. m (283 sq. ft), max speed: 1,020 kph, (634 mph), max weight: 7,446 kg (16,437 lbs), ceiling: 13,260 m (43,500 ft), armament: six 0.50 cal M3 heavy machine guns, engine: one Chevrolet J 35-C-3 axial flow turbojet rated at 4,000 lbs (1,812 kgf) static thrust.
Attachments
In Squadron/Signal's F-86 Sabre Walk Around, No. 21, on page 3, is two side views of the XP-86. But in this issue the straight wing XP-86 is different and more like an F-86 fuselage. Just above the side views is a photo of the mock-up shown elsewhere in this thread. The caption says it's the only known photo of it. But sometime ago I've seen another, which I think was in an Air-Britain AeroMilitaria article of another North American product, and the caption said 'notice the XP-86 in the background' or something to that effect.
I built my model (in an alternative history 'in service' scheme) using this side view as a guide.
Attachments
Pretty much. And it was an obvious starting point.
archipeppe
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Definitely not counting the Navy version that was pretty much closer to the original XP-86.
Well, Navy planes were always tubbier than land-based...
There is a missing geneology of the development of the P-86, beginning with jet propulsion mods to the P-51. With luck some of it will someday see the light, but a *lot* of NAA documentation was simply trashed decades ago.
Оne of the reasons for straight wings on the F-86 is better aerodynamics at slower landing speeds or when taking off . But the problem is that when straight wings are used at the ends there is a lot of resistance or mixing of different layers of air to reduce the resistance at the ends of the wings
these tanks are placed
these tanks are placed
The only thing close to a P-51 was the wing, more specifically it was practically a dead ringer to the P-51H wing, except for where the main gear were mounted. The fin/rudder were more like a F-82's in size. The tail plane was huge compared to the P-51's
In this photo, I had stacked the P-51D (top) with the P-51H (middle) and the XP-86 (bottom) so you can see the difference.
Attachments
The photo of the mock-up shows the XP-86 was built nothing like an FJ-1, two completely different airframes. For example, the wing for the XP-86 was built all in one (which you can see in the mock-up photo), the FJ-1 wings were separate and bolted to the sides of the fuselage.
Attachments
The wings, tails and cockpit canopy are all clearly descended from the P-51. They weren't parts straight from the P-51 catalog, but the family resemblance is there.
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You can achieve a big saving in effort even if it's not exactly the same part; just keeping the shape of the flying surfaces the same is going to make the aerodynamicists happy because the behavior is going to be known or predictable based on existing data.
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Agreed -- the canopy is very close to the XP-51F,G & J canopy. Which in turn is very similar to the FJ-1 canopy. When I build my three XP-51's I'll used the FJ-1 canopy for them.
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I should have been more clear. This is more my thought than "just slap a jet engine in a P-51."
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