1930s Air Ministry surprise sanity options
- Thread starter perfectgeneral
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I really like that side view, but naval pilots are going to have coniptions about a chin radiator for cooling as that makes any sea landing near certain to fail. Setting the cooling scoop further back also helps with the area rule. This is part of why the Mustang one is so effective. My that tail looks tall. Maybe later models can try a reduced tail for less drag?
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PS having adjustable vents in and out of the radiator belly bulge not only allow good Meredith Effect, but closing off for a water landing. fully open at the front and closed at the back acts as an air brake.
Miles M.24
That scoop. Those legs. Hmm.
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PS having adjustable vents in and out of the radiator belly bulge not only allow good Meredith Effect, but closing off for a water landing. fully open at the front and closed at the back acts as an air brake.
Miles M.24
That scoop. Those legs. Hmm.
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Chin radiator is far superior to the eg. belly radiator scoop for naval aircraft, that made Hurricane and proposed Sea Mustang dangerous for ditching. The area rule will do it's part once the speeds are close to sub-sonic and above, but not at the low-ish Mach numbers of .65-.70 that some of ww2 fighters were approaching.
Mustang was effective due to many things - efficient radiator layout, type of wing choosen, excellent fit & finish, fully retractable & covered U/C, low-ish weapon-related drag (no protruding barrels), being not too big nor too small, type of engine choosen in all iterations, fuel tankage that kept growing...
Mustang was effective due to many things - efficient radiator layout, type of wing choosen, excellent fit & finish, fully retractable & covered U/C, low-ish weapon-related drag (no protruding barrels), being not too big nor too small, type of engine choosen in all iterations, fuel tankage that kept growing...
That tail comes from the original prototype Kestrel, the reputed 295 mph one, before they klutzed up the cockpits and rear fuselage. I made the tailwheel retractable because I'm lazy. I've already made a Kestrel fighter before in my Handley Page gig, but it had fixed gear.
Really? I thought it mattered for critical airflow going faster than the aircraft. The fastest WW2 piston level speed was barely over .6 Mach .65 works out as 495mph and .70 as 533mph approx. They would have to be diving hard.
http://www.kylesconverter.com/speed-or-velocity/mach-number-to-miles-per-hour
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https://en.wikipedia.org/wiki/Critical_Mach_number
If you think of the body as a really thick wing, you can see how the critical Mach number would be even lower here and you would get drag at relatively low speeds.
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I think you're mixing up several aerodynamic principles, and the only one that applies to a 300 mph fighter is largely that thin is faster than thick, when it presents a larger frontal area. The critical mach number of a wing is important if the aircraft can exceed it, and such as Typhoon and Welkin suffered for it, but area rule wasn't recognized outside Germany until after the war, and only matters for aircraft expecting to operate at high trans-sonic and supersonic speeds. The Convair F-102 was the most famous application of a supersonic aircraft that wasn't, until it discovered the coke bottle. A jet airliner, designed to be subsonic, would have a wing with a critical mach number above its expected maximum speed, but without application of area rule, which would impinge on passenger volume.
Thanks.
I'm looking through a few graphs, as the maths notation means very little to me, and I can see that the percentage of the wing from the leading edge before the wing thickness reduces plays a large part in drag. So does the ratio of wing chord (leading to trailing edge distance) to maximum thickness.
Do I have that right?
I still don't see how a chin air scoop won't cause a ditching aircraft to pitch right over.
I'm looking through a few graphs, as the maths notation means very little to me, and I can see that the percentage of the wing from the leading edge before the wing thickness reduces plays a large part in drag. So does the ratio of wing chord (leading to trailing edge distance) to maximum thickness.
Do I have that right?
I still don't see how a chin air scoop won't cause a ditching aircraft to pitch right over.
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No, you don't really understand. Few really do. That's why they have the numbers and why you need the math. Wings aren't just drag, they are lift too. So the optimum you seek is good lift/drag within operating limits, depending on requirements and special factors. And it's all compromise.
Have a look at the Fairey Fulmar and Barracuda. Chin scoops. When ditching, one pitches the nose up slightly so the nose doesn't hit water first. The inverted gull wing on the Kestrel might help ditching buoyancy.
Admiral Beez
Banned
I like it. And, maybe we'll get the Kestrel-based Peregrine improved in time for the Whirlwind.
Whirlwind with two speed, uprated (100 octane fuel compatible) Peregrines. Suggest three cannons sit in a tray under the pilot (sat further forward) with double magazines behind. Extra 22lb drums. Extra ammo 33lb. New fuel tank behind that. Drop tank on each wing. Gives you 400mph at altitude and Mustang exceeding range.
Amazing details here:
https://www.rcgroups.com/forums/showthread.php?2106208-Westland-Whirlwind
http://www.whirlwindfighterproject.org/
The three RR production lines must be Peregrine (Whirlwind and trainers), Merlin (most RAF) and Griffon (most FAA).
Amazing details here:
https://www.rcgroups.com/forums/showthread.php?2106208-Westland-Whirlwind
http://www.whirlwindfighterproject.org/
The three RR production lines must be Peregrine (Whirlwind and trainers), Merlin (most RAF) and Griffon (most FAA).
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I just knocked those up to illustrate my points about possible better design for the first Whirlwind.
I'm puzzled as to why that "Wasp" has air inlets on each nacelle for housed radiators and radiators in the leading edges. Separate oil cooling system? They like the more forward sitting pilot. Added Merlins and wing area? Very hard to rebalance that much extra weight. The wings and body have got thicker. The prop discs probably obscure the outer cannons.
I lost a cannon and a lot of glass to lighten back from the extra fuel and ammo. I think 3x 20mm is still a good bomber killing punch and 120 rounds is twice the firing time from two extra drums.
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The intake under the cowling is for supercharger air into an updraft carburetor.
Closing the belly radiator makes ditching even more dangerous, the decelleration needs to be smooth, not abrupt.
Merredith effect helps with reducing radiator-produced drag. The radiator on the M.24 is firmly in the early 1930s - 'let's stick it out in the slipstream' school, that should've been abandoned after the Hurricane. An air brake indeed.
On the Mustang, Ki-61, D.520 and many Italian and Soviet fighters, the radiator was burried in the fuselage by a great deal, it's frontal surface being considerably bigger than surface of the inlet - that kept frontal surface as small as possible. That size disparity necessitated gradual increase of the area going between the inlet and radiator, meaning short intake tunnel does not work, while long tunnel does work. Let's also recall that on Mustang the radiator inlet, size and shape were changed at least four times going from P-51 to P-51H - meaning that a even a good radiator set-up was being perfected.
The Spitfire, Spiteful and Bf 109E-K also used half-burried radiators for lower drag.
That calculator lacks a major factor - altitude where conversation is taking place. Eg. Mach .65 at 30000 ft equals 440 mph, the P-51B and Spitfire XIV/21/22 just beating it a bit, while the P-51H, P-47M/N, Spiteful/Seafang were comfortably faster than Mach .65 at 30000 ft. Obvoiusly, during the dive they went much faster.
As the scoop finally hits the water the airframe pitches about that centre. If the scoop is at the front it lifts the airframe up as a whole and the deceleration quickly drops it back down again as the energy is taken up by dragging it through the water. With a central scoop it pivots around the centre so the nose dips under the water as the tail lifts. Then the water acts on the dipping nose to push it further under until either the whole is thrust so far underwater that it sinks right away or it rotates the tail right over the pivot and inverts the airframe. Either way is bad news for the driver and any peasants on board.
With wing radiators like a Seafire the pivot is also around the radiator scoops but the wing immediately is pushed flat onto the water and supports against the pitching effect. Better news for all concerned.
If one drags the tail onto the water first at near stalling speed the instant drag on the tail robs the airframe of lift and slams it down onto the water. With the area of the wings and fuselage it may as well be dropped onto concrete without the benefits of gradually dissipating the remaining energy in sliding along real concrete.
All of this was bad news for CAM Hurricane pilots who needed to drop into the sea very near a fast escort ship if they were going to be picked up. A parachute could both drop them far away from where they wanted to be and drown them tangled in the fabric and/or lines. The escort could only spare a few minutes to search and pick up. A ditching right off the escort's bow risked the CAM Hurricane flipping over. IIRC the idea was to ditch into a rising wave surface.
Pausing for thought. Would a chin radiator Hurricane allow a centre weapons point as well as the existing two wing ones? I appreciate that it moves the centre of gravity forwards. There is the Henley/Hotspur as some guide. Pop a TAG squeezed behind the pilot like the Russians did? Voila. We have the Skua replacement, or are we reinventing the Henley?
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Unless the Merlin gets a major make-over, that would've seen relocation of supercharger and intake manifolds, the prop-gun/cannon is out of the question. Hispano cannon, due to the way it worked, was unsuitable for synchronised installations, plus IIRC the Merlins never got gun synchronisers, so cannons will stay in the wings as historically. Use the Henley installation as a model/inspiration.
The chin radiator might've added a few mph to the speed, like it was the case with Typhoon and P-40 that were outfitted with belly radiators at 1st. Also clears the volume between the pilot's cabin and fuselage floor, previously used by radiators plumbing, so a nifty, say 30-40 gal tank might be located there? Less plumbing means lower probability that a single bullet/shrapnel might severe the oil or coolant flow, thus improving survivability.
Winkle Brown said the Seafire ditched like a submarine.
The Hurricane wheels met under the belly. That's why the Henley got a longer wing center section.
I was reading my copy of the First Report of the Defence Requirements Committee to do some fact checking and remembered this which might be of interest. These are the Air Defence Requirements of Singapore at 28th February 1934. Note that RAF Far East also required more aircraft for Hong Kong, Penang and Ceylon.
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