Improve That Design: How Aircraft Could Have Been Made Better

BarnOwlLover said:

How about a Spitfire with Spiteful-type radiators and inward retracting landing gear?

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Great idea, but what are you going to do about the much thicker airfoil the supporting structure for that landing gear will require, as well as the repositioning of the wing guns outward? Remember, the designer of the Hurricane later lamented the thick wing he saddled her with, in pursuit of simpler structural design. With a thinner airfoil, the Hurri might have been closer to the Spit in performance.

If I remember correctly, the Spiteful's wing was thinner than the Spitfire's. And the guns were just outside the propeller arc.

BarnOwlLover said:

How about a Spitfire with Spiteful-type radiators and inward retracting landing gear?

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Shallower and wider radiators were use on the Spiteful, so I agree with the proposal. Inward-retracting U/C might not went well with the propeller diameter, since, due to the Vee of the wing, ground clearance will be lower for the same length of U/C legs.
I'm not sure that Spitfire have had that much of the problems due to the main U/C retracting outwards.

One thing the late marque Spitfires have had was the fully retractable and covered U/C, that might gain another +-10 mph vs. what Spitfire IX had?

Which one of these would be best to make an even better P-51 Mustang:

1: Modify it to be built to British design standards with product improvement upgrades and same Packard Merlin engines (XP-51F),

2: Keep the basic B/C/D/K airframe and hope for the Merlin 100 or V-1650-9/11 engines (A Mustang III/P-51B was tested with a Merlin 100 engine, and at a take off weight of 9600-9700 lbs reached 455 mph top speed and an initial climb rate of 4300-4400 fpm per RAE report), or,

3: Do both and get the P-51H/L/M into production quicker?

It should be noted that the FW-190 for example 2, with the BMW 801, weighed almost 10,000 lbs max take off weight, the FW-190D and Ta-152H had a normal "clean" take off weight of 9400 or so lbs. But all (even the Ta-152) had significantly less range on internal fuel than the P-51. We know from the P-51H and the XP-51F/G that the B/C/D/K were kind of overbuilt, but I wonder how "overbuilt" the FW-190 was, given it's weight vs fuel capacity/range, and that a standard Merlin Mustang could climb as fast or faster initially than the FW-190 or Ta-152 initially.

Also, is there a way that anyone knows of to make the DH Hornet have agility similar to the P-38?

BarnOwlLover said:

Also, is there a way that anyone knows of to make the DH Hornet have agility similar to the P-38?

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Only fly it on one engine ?

BarnOwlLover said:

Also, is there a way that anyone knows of to make the DH Hornet have agility similar to the P-38?

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What is posted just above is pure gold - it was P-38 that needed to up it's game, not the Hornet.

I did read in Tony Buttler's book about the Hornet that it's maneuverability, especially roll rate, wasn't great. However, it was compared to single seaters, like the Spitfire, Mustang and even the Vampire. Later P-38s did have powered ailerons, and even early versions were attested by German pilots as being able to out-turn them, though their roll rate until the powered ailerons came in was relatively poor.

Based on Buttler's book, I can't see the Hornet as out-turning most German single seaters, though it could climb much faster than most and was much faster. Same applies vs the P-38.

Of course, I do wonder how the F-82 compared to the Hornet.

BarnOwlLover said:

Later P-38s did have powered ailerons, and even early versions were attested by German pilots as being able to out-turn them, though their roll rate until the powered ailerons came in was relatively poor.

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The P38 was an older design, dating back to early days of all metal monoplane fighters, and had more of a high lift airfoil (hence its compressibility and critical Mach issues). This, plus it's high thrust available allowed it to sustain a high G turn with less energy bleed than a less powerful single seater with a thinner, more speed-oriented wing, at dogfight speeds. Add a combat flap, and the turning advantage increases.
Any multi engine fighter (other than centerline thrust) is going to suffer a penalty in roll rate, due to the polar moment of its distributed mass. The effects of this penalty are going to depend on the strength of the roll moment the ailerons, spoilers, or other roll control devices can generate. On the face of it, it would appear the F82 might have more laterally distributed mass than either a Hornet or a Lightning. So, did NA compensate for this in designing the twin pony's roll controls? Can two hands on two sticks generate enough additional roll authority to compensate for the distributed mass?
Stay tuned.

F-82s used asymmetric boosted controls linked to each pilot's stick due to trying to roll the plane about an asymmetric axis. I don't know if this had any positive effect on roll rate.

XBe02Drvr said:

The P38 was an older design, dating back to early days of all metal monoplane fighters, and had more of a high lift airfoil (hence its compressibility and critical Mach issues).

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Wing on the P-38 have had the 16% t-t-c at root (NACA 23016). This is same as P-47, whose compressibility problems were much less severe.
The F4U was at 18% (NACA 23018), F8F was at 19% - again less issues with high-speed dives.
NACA stated also the steep windscreen and abrupt ending of the pod as culprits for the low compressibility limit.
Granted, compressibility was better known a problem when P-38 entered service, than it was the case when it was being designed.

Manual for the P-38 notes that a lot of the compressibility problems were due to the pod and nacelle creating a venturi (obviously x2 per aircraft), that made the airflow speed up.

Granted, making a twin as agile as a single seater is almost always a tall task, but could anything be done to make the Hornet even better in that aspect?

Also, would handed engines (like on the Hornet) have been of much use on the Mosquito beyond being a bit of a quality of life improvement for the pilot?

And for a plane like the Mosquito (or any other similar SHTF combat planes of World War II, like several promising French designs), what would've been better, the Mosquito's construction method, the use of Duramold wooden construction, or a mix of both?

BarnOwlLover said:

Granted, making a twin as agile as a single seater is almost always a tall task, but could anything be done to make the Hornet even better in that aspect?

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ADI for the engines, powered controls (at lest ailerons), Fowler flaps?

Duramold composite is significantly more dense than the plywood/balsa/plywood sandwich and solid wood structure used on the Mosquito.

But, at least in theory, the phenol impregnated plywood structure of the Duramold type would have needed a lower safety factor due to its mooted lower probability of crack propagation. It would also probably have survived adverse climate conditions better than the Mosquito structure.

Unfortunately, there were only 2 airframes (I think) made ~entirely of Duramold - the Fairchild F-46A and the Hughes H-4 Spruce Goose so there is very little information as to how successful the material would have been during the WWII era. The Spruce Goose came out grossly overweight and only flew once for a very short distance, so the F-46A is the only airframe that was flown to any extent (~20 years??). I have never been able to find any flight test or structural strength/fatigue assessment data for the F-46A.

BarnOwlLover said:

And for a plane like the Mosquito (or any other similar SHTF combat planes of World War II, like several promising French designs), what would've been better, the Mosquito's construction method, the use of Duramold wooden construction, or a mix of both?

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Kind of depends what you want to do.
The Mosquito was not stressed for fighter style maneuvers. I believe the practical limit was about 6 Gs ?
If you want the same plane to act like a fighter you need a stronger structure Which means more weight and less internal volume (keeping the same external shape/drag).
You also have to have the Material to actually build the desired aircraft in quantity. Classic case the Langley Twin.

Note that even the cowls were made of laminated molded wood. Very few metal fasteners were used.
However even this small twin needed over 50 gallons of vinyl and phenol resins and the amount of resins needed turned out to be in shorter supply than metal.
One account of the French aircraft says that only about 10% of the purchased spruce wood was suitable for aircraft construction. And the French had no suitable domestic Spruce, it all had to be imported. You can't sort the spruce wood until the tree is cut and sent through the sawmill and then it needs drying.
Getting wood you can make a spar for 350mph airplane that will pull (repeatedly) 6Gs is a whole lot different than building a spar for a 175mph airplane that pulls 3.5 Gs.
Duramold was used for a lot of small parts for aircraft as it was. Crew seats, bulkheads, hatches, non stress panals.

This would probably be better suited for it's own thread, but is there any other materials other than wood and metals (namely aluminum and steel alloys) that can be viable for use for aircraft that's "non-strategic"? Such as something like Aerolite or something else that might have been explored?

A couple of forms of fiber-glass were experimented with as early as the WWI period, but making the consistency/quality of glass fiber and the resins needed was difficult/expensive for the time. Plus wood and aluminum (once the cost of production went down) worked well enough.

The Spitfire had a fuselage made of Gordon Aerolite flax and resin material in lieu of aluminium in 1940

I am not sure if this is an example of a better or a much worse design. However, let us imagine that Vice-Admiral Tsukahara Nishizo had been shocked when appointed head of Naval Air Command on 1st December 1942 and realised that no replacement for the A6M Zero was likely to enter production in the near future and demanded that variants be developed with more powerful engines. Mitsubishi would happily suggest the Kinsei 60 series and that would be a good idea. However, imagine that Tsukahara is suspicious of Mitsubishi's motives and demanded that an A6M variant also be developed powered by Nakajima's Homare 11 whilst utilising as much as possible of the existing production jigs.

At first sight, there are no insuperable problems. The Homare is 1180 mm wide compared to 1150 mm for a Sakae 21 and is longer at 1690 mm compared to 1472 mm for the Sakae 21 but we know that a Kinsei 62 which is wider at 1218 mm and almost as long at 1660 mm fitted into an A6M8.

The obvious problems are caused by the weight and the increased power. The Homare 11 weighed 830 kg compared to 530 kg for the Sakae (the Kinsei 62 is half way at 675 kg). The power will probably need a 4 bladed prop and the Ki-84's 3.1 m disk is similar to the A6M5's 3.05 m 3 bladed disk (extended to 3.15 m for the A6M8).

We could try to solve some of the CoG problems by moving the cockpit back. The pilot of a Zero (or an F4F) sat near the CoG whilst the pilot of a Hayate (or an Fw 190) sat near the rear edge of the wing. Can we simply add a section of fuselage in front of the cockpit increasing the length of the aircraft to that of the Ki-84? We can also add the armour added in the A6M5c or possibly rather more. The longer fuselage may also compensate for the effects of a four blade propeller and the added power. It might allows us to expand the fuselage fuel tank to regain the A6M2's range but will we have to learn a curved approach from the FAA and is that consistent with the IJN's landing light system?

Everything adds weight and then maintaining structural strength adds more weight and a stronger undercarriage adds more weight. The A6M8 actually weighed much the same as the A6M5c as the removal of the 13.2 mm machine gun balanced the heavier engine. Thus for total weight rather than CoG only the extra 155 kg of the Homare counts plus the larger fuel and oil tanks and any extra armour. Will the new empty weight be about that of a Ki-84 (2,660 kg compared to 2,150 kg for a A6M8)?

How large a fuel tank do we need? Since the Ki-84 has the same wing area and the same engine, its 696 litres for 1025 miles at 178 mph or 780 mls at 254 mph gives us some idea. The A6M5 only carried 540 lites of internal fuel but there is a complication. The A6M5's tanks were not self sealing. The A6M6c had self sealing tanks quoted as 610 litres but the A6M6c's range is given as 956 miles at 230mph compared to 1314 miles for the A6M5c (most of the above from Zero Facts and Figures). It looks as if the extra tankage should have at least 200 litres volume, which requires roughly 200 mm length if it is a cylinder of the same diameter as the engine. That will obviously fit as the Ki-84 is about 0.8 metres longer than the A6M5. 200 litres of aviation fuel would weigh roughly 144 kg which will count when calculating performance.

Our imaginary Vice-Admiral Tsukahara might have a point. More than thirty Gingas powered by the Homare took part in the Marianas battles https://www.historyofwar.org/Pictures/pictures_USS_Corregidor_CVE58_yokosuka_P1Y.html, so there is no reason that some of this variant cannot take part if no serious problems are encountered.

Our venerable Admiral can say to himself: it might take too long before we actually have the Homare-powered Zero, and we need the better carrier-borne fighters yesterday. Perhaps have Nakajima slap the Ha 109 on the Zero as-is?