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
MustangFlyer    RE: Roll Rates   2/6/2006 3:21:26 AM
Could be, that is a very impressive boosted rate of roll at high speed for a twin engined plane. Obviously in a late model P38 you'd want to keep the speed up in combat (same as a Mustang) and keep in your best envelope .. though the other guy is of course trying to do the same to you as well. Another indication of how important it was to know not only your plane's strength and weaknesses and how to use them, but your opponents as well.
 
Quote    Reply

larryjcr    RE: Roll Rates   2/6/2006 10:41:27 AM
It always has been. The real turning point in the PTO was when Allied pilots realized that the Zero's handling fell off rapidly with speed, and they COULD fight with it successfully by keeping their speed high.
 
Quote    Reply

larryjcr    RE: Roll Rates   2/6/2006 9:37:24 PM
By the way, the Mitsubishi people tried to solve the Zero's limited roll rate the same way -- by removing the wingtips of the A6M2 as part of the upgrade to the A6M3. This increased the speed at which roll performance fell off sharply by about 50 mph and the difference in wingspan was just over three feet.
 
Quote    Reply

Shooter    RE: Roll Rates   2/7/2006 4:18:55 PM
The twist problem had nothing to do with the wings thickness as the post below claims. >>The big issue for the Spit was wing twist, a price paid for being so thin.<< The problem was caused by the single spar used to save weight!
 
Quote    Reply

Shooter    RE: Roll Rates- This was actually the one I wanted to post   2/7/2006 4:34:52 PM
There are lots of reasons why any two other wise identicle looking planes will have very different rates of role. The control stick might be longer or shorter and have more or less leverage. The wings might twist more or less, thus negating the aileron forces by more or less. The feel might be different, such that the pilot uses more or less force regardless of the requirement. The list goes on and on. I note that Mustangflyer was impressed with the 'stang's rate of roll, but the stang was not known for sparkling responce to side stick. The Spit was known as a lite and easy plane to fly, but was deffinately infirior to it's contemporaries. Some of this was a lack of instramentation in the Spit which did not have a "G" meter and in some models an artificial horizon! (A few early war planes.) But in all cases it is the pilots perception of what is going on, not the instramented or side by side comparison.
 
Quote    Reply

Shooter    RE: Roll Rates   2/7/2006 4:50:35 PM
This is a very important point to make! The knowledge of both your and the oppo's plane makes for a world of advantage IF you are in your sweet spot and he is out of his! Secondly, few here have said anything about the P-factor. The prop acts like the giant gyroscope and torque generator that it is. Any plane with contra rotating props will have significant areas of the curve where it will have huge advantages over any single prop plane. Want to out roll a FW-190 or P-47, just go against their torque imputs and they are terribly slow. Same with the spit/'stang which are much worse. Also used the whole envelope! the P-38 with its contra props can pull much more throttle at low speed than any of the others and can thus turn inside ANY of them down and dirty, without off side stalling!
 
Quote    Reply

AussieEngineer    RE: Roll Rates   2/7/2006 9:16:12 PM
Torque cuts both ways remember, slower in one direction faster in the other
 
Quote    Reply

oldbutnotwise    RE: Roll Rates   2/8/2006 3:26:44 AM
shooter strikes again. shhoter please provide evidence of the spits "weak" wings, the spits central spar and monoque leading edge created a very strong wing but as been pointed out allowed twist. I can find no independant evidence that a P38 could out turn a spit or a mustang, and it need a lot of help to out roll one, the power control were developed for the p38 pricesely because it was being outperformed by every thing else, the proof is that the same power control were not regarded as needed on the p51 or spit (or later bearcats and furies), because they found a way of hiding the problem doesnt mean the problem isnt there!
 
Quote    Reply

MustangFlyer    RE: Roll Rates   2/8/2006 6:37:54 AM
>>This is a very important point to make! The knowledge of both your and the oppo's plane makes for a world of advantage IF you are in your sweet spot and he is out of his!<< Agree entirely. The best pilots all had superb machine control and the ability to predict an opponent’s moves. >>Secondly, few here have said anything about the P-factor. The prop acts like the giant gyroscope and torque generator that it is. Any plane with contra rotating props will have significant areas of the curve where it will have huge advantages over any single prop plane. Want to out roll a FW-190 or P-47, just go against their torque imputs and they are terribly slow. Same with the spit/'stang which are much worse. Also used the whole envelope! the P-38 with its contra props can pull much more throttle at low speed than any of the others and can thus turn inside ANY of them down and dirty, without off side stalling!<< Negative on P-38. Simply put you have more inertia to overcome with the mass of the engines. The force to overcome this inertia comes from deflected airflow from the ailerons. At slow speed there is little force, at higher speed there is greater force. At higher speeds other aerodynamic factors come into effect that affect aileron effectiveness such as wing twist or under/over balancing). The P-38 had good performance only at very high speeds. Overall excellent for a twin engined plane .. “but you canna defy the laws of physics” (Scotty). Torque is only an issue at low (basically take off and landing) speeds. Aerodynamic forces dominate once you get faster (say above 200mph). The effect you are mentioning (tendency to roll better in one direction than the other) is caused by prop wash affecting the rudder. Turning can also be affected by differential prop wash on elevators. >>There are lots of reasons why any two other wise identicle looking planes will have very different rates of role. The control stick might be longer or shorter and have more or less leverage. The wings might twist more or less, thus negating the aileron forces by more or less. The feel might be different, such that the pilot uses more or less force regardless of the requirement. The list goes on and on.<< Read the NACA report. Control stick was not an issue in these cases as all stick deflection and forces were carefully set and measured. These were not tests of the controls, these were tests of the aircrafts capabilities, with analyses of the reasons. Aileron design, wing design, rudder design, mass, etc were all factors. >>I note that Mustangflyer was impressed with the 'stang's rate of roll, but the stang was not known for sparkling responce to side stick. << Really? Felt light and responsive to me. I’d like a source for that claim, the Mustang is well reported in many tests for good positive controls. >>The Spit was known as a lite and easy plane to fly, but was deffinately infirior to it's contemporaries.<< We’ve had this discussion many times, it was not inferior. It was a highly dangerous and competitive plane across a range of flight envelopes right to the end of the war. >>Some of this was a lack of instramentation in the Spit which did not have a "G" meter and in some models an artificial horizon! (A few early war planes.)<< All production Spits had artificial horizons in combat. Not sure what use a G meter is for rolling. Only useful for pulling out of dives and turning. Surprisingly few Spits suffered damage from over G as the wings were very strong. Largest group was from fighter bombers in the pull up from dives, where the pilots often blacked out, when some rippling was reported. I have a reported case of a pilot who destroyed a Spit (still flew and he landed it ok) by over pulling out of dive, it was estimated that he shouldn’t have survived the G force. The Spit was rated to 10g. >>But in all cases it is the pilots perception of what is going on, not the instramented or side by side comparison.<< No. A Fw 190 is going to out roll a P38, P47 or Mustang up to very high speeds whatever you feel. Only a clipped wing Spit will stay with it. >>The twist problem had nothing to do with the wings thickness as the post below claims. The problem was caused by the single spar used to save weight!<< Not sure what you mean. The wing design was thin (for drag performance and speed) and light (for climb performance). The single spar design was used on (and still is used) on quite few planes (e.g. Me 109). Lighter weight plus large wing area = low wing loading = good climb and turn performance. The Spit out climbed and out turned everything to the end of the war (on a comparable model basis). Usually a low wing loading would mean more drag and less speed, but because the Spits wing was the thinnest around it was also fast (brilliant mach performance as well). Price paid was greater wing twist at high speeds and the affect on aileron performance.
 
Quote    Reply

larryjcr    RE: Roll Rates   2/8/2006 6:24:01 PM
While the clipped wing Spit certainly improved roll rate, I much doubt it got up to the level of a Thunderbolt on that. At least the practical accounts from pilots at the time contradict that. Twisting was a problem with single spar wings as long as there have been fighters. The Nieuport 11, 17 and 27, as well as the Albatros D3 of WW1 all had the same problem. The Spitfire was, of course, much stronger, but it would still be a much worse problem than for anything with a two spar wing structure. Note that the '109 didn't have much of a roll rate either. The flight reports on that Spitfire site you gave the ad. for were critical of the horizontal turn rate of the Mustang, considering it fairly poor for an a/c in its class. P51 pilots used the same, zoom and spiral down tactic that the P47 pilots developed to turn with '109s and '190s rather than tail chasing them. Wing loading wasn't the only factor in climb rate. From that Spitfire site, and a few other places I've compiled a list of climb times to 20K (slightly different but close for the German types: SpitfireXIV- 5.1 min. P38J - 5.37 min. SpitfireIX - 5.6 min. Bf109G-6 - 6.0 min. (to 19K) SpitfireXII- 6.7 min. P51B - 7.0 min. FW190D-9 - 7.1 min. (to 19.685K) P51D - 7.3 min. Engine power and airframe 'slickness' are also major factors.
 
Quote    Reply



 Latest
 News
 
 Most
 Read
 
 Most
 Commented
 Hot
 Topics