Military History | How To Make War | Wars Around the World Rules of Use How to Behave on an Internet Forum
Fighters, Bombers and Recon Discussion Board
   Return to Topic Page
Subject: How to fix the design defects of the Spitfire airplane of WW-II.
Shooter    5/26/2005 5:12:16 PM
Given 20-20 hind sight, It is easy to see where R.M. went wrong with the Spitfire! The following list of items is my idea of how they should have done it, IF THEY HAD READ ANY OF THE COMMON TEXTS instead of designing a newer SPAD for the last war! 1. Start with the late Seafire or even better the Martin Baker MB-5! they have contra props and wide track gear. The MB-5 also has a much higher LOS out of the pit forward. This is also one of the Spits larger problems. 2. Change the shape/planform of the wing and eppinage from eliptical to trapiziodal. The eliptical surfaces caused the construction time and cost of the Spitfire to be more than double that of the Mustang and almost as much as the P-38. 3. Reduce the wing cord and thus area by 35-40%! This reduction in surface aria will increase the cruising speed substantialy! This is probably the single biggest defect in the design. The change in aspect ratio will also help fuel ecconomy! 4. To compensate for the increased landing and take off speeds install triple slotted fowler flaps with a long hinge extension. This gives a huge increase in wing area and changes the camber for supirior "DOG FIGHT" ability, should you ever need it! ( because the pilot really screwed up!) At full extension and deflection, they would reduce the landing speed by 11~13MPH? (Slip Stick calcs!) 5. Remove the wing mounted radiators and install a body duct like the P-51 or MB-5! This one change would add ~35MPH to the plane? 6. use the single stage griphon engine and install a "Turbo-charger" like the P-38 and Most American Bombers had. This would increase power and save weight, both significant contributers to performance. 7. Remove the guns from the wings! This would lower the polar moment of rotation and give the plane snappier rates of roll! It also makes room for "wet wings" with much more fuel. A chronic Spit problem. It also fixes the Spit's gunnery problem of designed in dispersion! 8. Install the Gun(s) in the nose! Either fireing threw the prop boss/hub or on either side 180 degrees either side of the prop CL. This fixes the afore mentioned dispersion problem. One bigger gun between the cilinder banks or upto four 20MMs beside the engine or both, depending on what your mission needs were! 9. Make a new gun based on the American 28MM or 1.1" Naval AA ammo! This shell was particuarly destructive, had a very high MV and BC and was all ready in service. A re-engineered copy of the existing gun to reduce weight and increase RoF is a faily simple task. Pay the Americans for it if British spring technology is not up to the task! it also frees up much needed production capasity for other things. 10. Design a new drawn steel "Mine" shell for the above gun! Spend the money to load it with RDX instead of the TNT used for the first 4/5s of the war. 11. Pay North American or Lockheed to design it for you, since the Supermarine staff was to tied up fixing the origional spitfire design to get it done any time soon. Did I miss anything?
 
Quote    Reply

Show Only Poster Name and Title     Newest to Oldest
AussieEngineer    RE:p40 and the BOB   12/21/2005 3:44:58 AM
P-40E; shooter was talking about the Allison powered P-40s I believe. While the P-40F was an improvement over the P-40E it still didn't have the performance of the Spit III (Merlin XX, a very similar engine to what the P-40F had IIRC) or the Spit V (Merlin 45).
 
Quote    Reply

MustangFlyer    RE:P 40 (much much more)   12/21/2005 3:48:59 AM
From http://www.aviation-history.com/curtiss/p40.html. "The P-40 was initially designed around the Allison V-1710 liquid-cooled inline engine which offered better streamlining, more power per unit of frontal area, and better specific fuel consumption than did air-cooled radials of comparable power. Unfortunately, the rated altitude of the Allison engine was only some 12,000 feet, rendering combat above 15,000 feet a completely impracticable proposition. " And more,much much more (I'll get to the steak knifes soon) from http://www.warbirdforum.com/p040.htm (selected clips summarised .. please read the whole article) NOTE: date of delivery to the UK ... wasn't the BOB over by then? "The P-40 was the best known Curtiss-Wright airplane of World War II. It was also one of the most controversial fighters of the war. It was vilified by many as being too slow, lacking in maneuverability, having too low a climbing rate, and being largely obsolescent by contemporary world standards even before it was placed in production. The inadequacies of the P-40 were even the subject of a Congressional investigation. It gets regularly included on lists of the worst combat aircraft of World War 2. ..... The P-40 was obsolete by European standards even before the first prototype flew, and it never did catch up. Its Initial inadequacies in the form of low firepower and lack of self-sealing fuel tanks or armor were a reflection of mid-'thirties USAAC requirements which were outmoded. The P-40 had been developed as basically a low-altitude close-support fighter under mid-1930s US tactical concepts which envisaged more need for low-level ground support operations than for high-altitude interceptions. The military doctrine of the "ascendancy of bombardment over pursuit" was dominant in 1937 when the P-40 first appeared. This doctrine assumed that the prospect of high-altitude enemy air attack on the USA was extremely remote, with coastal defense and ground attack in the defense of US territory being seen as the the main tasks for any future fighter aircraft. Low-altitude performance and rugged construction received priority over high-altitude capabilities. ..... The maximum speed of the XP-40 was 342 mph at 12,200 feet at a gross weight of 6260 pounds. This was faster than the Hawker Hurricane, but slower than the Spitfire or the Bf 109E. Empty weight was 5417 pounds, and fully-loaded weight was 6870 pounds. Range was 460 miles at 299 mph with 100 gallons of fuel. With 159 gallons of fuel at 200 mph, a range of 1180 miles was claimed, almost twice that of the contemporary Hurricane, Spitfire, and Bf 109E. Wingspan was 37 feet 4 inches, wing area was 236 square feet, length was 31 feet 1 inch, and height was 12 feet 4 inches. The wingspan and wing area were to remain the same throughout the entire history of the P-40 production run. ...... The initial P-40 order was finally completed with 193 P-40Cs (company designation H81-B). Serials were 41-13328/13520. The first flight of a P-40C was made on April 10, 1941. The P-40C retained the 1150 hp Allison V-1710-33 engine, but was fitted with a new fuel system with 134 gallons in new tanks with improved self sealing. In addition, provisions were made for a 52-gallon drop tank below the fuselage. The P-40C had a SCR-247N radio instead of the SCR-283. These additions produced yet another upward crawl in the weight --- the weights for the P-40C were 5812 pounds empty, 7459 pounds gross, and 8058 pounds maximum loaded. Consequently, the performance continued to degrade. Maximum speed was 345 mph at 15,000 feet. Normal and maximum ranges were 730 and 945 miles respectively. Service ceiling was 29,500 feet, and initial climb rate was 2650 feet per minute. Dimensions were wingspan 27 feet 3 1/2 inches, length 31 feet 8 1/2 inches, height 10 feet 7 inches, wing area 236 square feet. ..... The USAAC had agreed to defer deliveries of their P-40s so that the Tomahawk Is could be supplied to Britain as soon as possible. The first Tomahawk Is reached England in September of 1940. .... However, Britain quickly concluded that these planes were not suitable for combat, since they lacked armor protection for the pilot, armor-glass windshields, or self-sealing fuel tanks. Nevertheless, since a German invasion was feared to be imminent, they were actually issued to several operational squadrons. .... The Tomahawk IIs were active in the Middle East from October of 1941 onward. They shared in the strafing of the retreating Axis troops. The ability of the Tomahawk to absorb an incredible amount of punishment became almost legendary. They served with Nos 2, 26, 73, 112, 136, 168, 239, 241, 250, 403, 414, 430 and 616 Squadrons of the RAF. They also served with Nos 2 and 4 Squadrons of the South African Air Force and No 3 Squadron of the Royal Australian Air Force. At low altitudes, the Tomahawk II was actually superior to the Bf 109, but this advantage rapidly disappeared whe
 
Quote    Reply

MustangFlyer    RE:Aspect Ratios   12/21/2005 3:49:56 AM
Thanks for the interesting data, but the Spit VIII number looks odd.
 
Quote    Reply

AussieEngineer    RE:Aspect Ratios   12/21/2005 4:03:25 AM
At first I thought it might be for with the extended wing tips, but it is an LF VIII and I don't think they were actually fitted with the extended tips. Here's where I got the info any way. http://www.spitfireperformance.com/spit8adsaussie.jpg" width=650>
 
Quote    Reply

AussieEngineer    RE:Aspect Ratios   12/21/2005 4:10:38 AM
It must be for extended tips, the Temora mkVIII website has a 11.23m wingspan and 22.5 m^2 area, which gives a 5.6 AR as well. http://www.aviationmuseum.com.au/aircraft/Spitfire.cfm
 
Quote    Reply

MustangFlyer    RE:Aspect Ratios   12/21/2005 4:25:57 AM
Thbnaks for that, I get the same nunbers you do. The calculation is fine but I've got a span of 36' 10" for the VII F,LF & HF, and an aspect ratio 5.6, which is right on the nose. The 'C' wing had an area of 231 sq ft vs a 220 net or a 242 gross for the normal one. Ah I've got it. Took a big of digging. It must have been an old one with the Mk VII wing, that had an aspect ratio of 6.5. The Mk VIII was basically an unpressurised VII. Looking through the serial numbers I see JF275, 2nd model which was tropicalised. They switched to the standard size wing very early one.
 
Quote    Reply

MustangFlyer    Speeling Erorss   12/21/2005 4:27:55 AM
Whoops, got my fingers caught up on the last post, apologies.
 
Quote    Reply

larryjcr    RE:p40 and the BOB   12/21/2005 2:56:51 PM
To AussieEngineer and MustangFlyer: I have explained repeatedly why the production history of the actual P40 a/c is not relevant to the discussion. I see no reason to repeat that explaination yet again.
 
Quote    Reply

AussieEngineer    RE:p40 and the BOB   12/21/2005 6:59:34 PM
I know. But I do disagree that the hypothetical 'Merlin Hawk' would have been a better choice than the spitfire. The spitfire was indeed short ranged and more range would have made it more useful through the rest of the war, particularly 41,42 and 43. With that in mind, my view is that a better choice than the 'Merlin Hawk' would have been a spitfire with about 50%-60% more fuel. I don't think there was a major design flaw in the spit other than short range and that only really becomes obvious with hindsight.
 
Quote    Reply

larryjcr    RE:p40 and the BOB   12/21/2005 11:38:14 PM
And there's exactly the problem. The Spitfire design precluded the addition of enough fuel to improve the situation more than marginally. The original 85 gal. internal was stretched to 95. After the MkVIII another 35 was added in the wings, and that was it for internal fuel usable in combat. Even if it could have carried an unlimited supply externally (and the RAF found anything more than 50 gal. external to be impractical), or in rear fuselage tanks, even the MkVIII, the longest range Spit, could not exceed a combat radius of about 520 miles. A Spitfire that could carry more internal fuel wouldn't have been a Spitfire at all. As to flaws, I would also add the weak landing gear and the poor shooting stability. That last was mitigated to a degree by the close style of combat, but tended to discourage use of the more effective, hit and run style. And the importance of the lack of high altitude performance in the Allison/P40 was only obvious in hindsight -- that didn't make it less of a flaw.
 
Quote    Reply



 Latest
 News
 
 Most
 Read
 
 Most
 Commented
 Hot
 Topics