wuzak
Captain
Closed undercarriage did not make it to VIII/XIV production.
Spitfire Combat Radius (range) evolution, limitations?
- Thread starter IdahoRenegade
- Start date
Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
Closed undercarriage did not make it to VIII/XIV production.
It wasn't until the Mk21 that production Spits had closed under carriage but it was developed way back in 1940
Not of the same layout and construction, though. The early type was all on the U/C leg, the actual, later type was a device attached directly to the wing (similar as on the Bf 109K).
Hi
The 'early type' is what was originally fitted to the Spitfire prototype K5054 and was removed in July 1936, information on this can be found on page 45 of 'The Spitfire Story' by Alfred Price, the removal appears to have made little difference to performance:
The same source includes images:
Mike
Hi
The Hurricane prototype also had a similar undercarriage door arrangement as the Spitfire prototype, in addition it had a retractable tail wheel. Both of these items were not on the production version:
The later Typhoon did have a fully enclosed undercarriage as did the Defiant and Fulmar. The P-40, Wildcat, Hellcat also did not have fully enclosed undercarriages although coming into service later than the Spitfire, while the P-47 and P-51 designs did.
Reference to rivets has been made previously, the Spitfire prototype was fully flush riveted but this made production more complicated and expensive, probably because thin alloy skin would mean the rivet hole would be "dimpled" rather than countersunk. In turn the structure it was attached to would also be "dimpled" which could also involve heat treatment therefore increasing cost and time to production. Supermarine undertook the famous "split pea" experiment to get accurate data on the drag caused by rivets on different parts of the airframe, an exert from 'The Spitfire Story', page 49 below:
Compromises to aid production and reduce costs, if possible, were always being made.
Mike
The Hurricane prototype also had a similar undercarriage door arrangement as the Spitfire prototype, in addition it had a retractable tail wheel. Both of these items were not on the production version:
The later Typhoon did have a fully enclosed undercarriage as did the Defiant and Fulmar. The P-40, Wildcat, Hellcat also did not have fully enclosed undercarriages although coming into service later than the Spitfire, while the P-47 and P-51 designs did.
Reference to rivets has been made previously, the Spitfire prototype was fully flush riveted but this made production more complicated and expensive, probably because thin alloy skin would mean the rivet hole would be "dimpled" rather than countersunk. In turn the structure it was attached to would also be "dimpled" which could also involve heat treatment therefore increasing cost and time to production. Supermarine undertook the famous "split pea" experiment to get accurate data on the drag caused by rivets on different parts of the airframe, an exert from 'The Spitfire Story', page 49 below:
Compromises to aid production and reduce costs, if possible, were always being made.
Mike
So the Mk.V was a product of an emergency need? I assume that would have made a retractible gear impossible to fit into the design?
Okay, so the Mk.21's wing was NOT a laminar flow design?
So the problem had to do with the ailerons being too light and reduction in directional stability?
Last edited:
Laminar flow wings aren't the be all to end all, one of the reasons pilots of all skill levels could master the Spit and have confidence in it was it's vice free beautiful handling from 400mph down too the stall, laminar flow wings can't give you that, one of the prototype Spiteful's crashed when the laminar flow wings stalled trying to turn with a MkXIV.
drgondog
Major
Not all Low Drag (there were no laminar flow wings) performed alike. The NACA 66 series adopted and modified by Bell displayed vicious stall characteristics at stall. The NAA/NACA 45-100 series for the pre-Lightweight Mustangs had no serious vices. A Flat spin, if entered, was difficult to recover from - but that is not entirely due to the wing characteristics. High speed departures at high AoA occurred on P-51, Fw 190, Spit, Bf 109, P-47 - etc. Common when outboard wing stalls before inboard, due to 'too high' AoA. The slat deployment on the 109 did, however give better warning.
Bill - how much of the help was the washout at Spitfire (wing root having 2 deg greater incidence angle than tip)?
Wrt. and IMO for the laminar flow wing application to the Spitfire: about as useful as giving an antibiotic to a man with a sprained ankle?
I actually knew that, but I remember somebody saying it was a redesigned foil that was supposedly laminar flow. It appears that it might not be, but I know the Spitfire generally did very well at high speed because of the following...
- The wings were very thin and that served to limit the rise of shockwaves until relatively high mach numbers, and were heavily filleted, and this helped keep the airflow smooth over the horizontal stab
- The fuselage was also very thin, and this served to limit the degree to which it parted the air, and minimized turbulence, which allowed the tail surfaces to be smaller
- The Air Ministry wanted the tails enlarged because they felt they were too small. While the tail wasn't enlarged to the degree the Air Ministry dictated owing to some haggling by supermarine, it was larger than truthfully needed.
No ww2 wings had laminar flow except possibly at taxi speeds.
Well yeah, but the issue was what were generally called laminar flow wings. Have they ever made a wing that was laminar at high speeds without using suction?
drgondog
Major
A lot of variables are involved in the discussion of Wing vs Airfoil properties. First the Spit airfoil was NACA 2213 Root and 2209 Tip, with a double ellipse planform to 'nudge' the lifting line along the 25% chord withCenter of pressure consistent along the spar. very efficient structurally with the spar more or less co-incident with the CP, span wise.
IIRC the wash out was 2 1/2 degrees. With CP ~ 26 % Chord
The NAA/NACA 45-100 airfoil was 16% root, 11% tip - with 1 degree 53 minute twist for wash out. CP~ 37% of chord. The Mustang CL was lower, form drag at high speed was lower, but the Spitfire Induced drag was significantly lower - and important at low medium speeds.
The lift distribution was better for the Spitfire Before the twist was introduced to 'push' it out toward the tip with the increased 'tip' washout
The Spit wing combined with low W/L was a superior maneuver aircraft to the P-51, but the wing of the 51 was a marvel
.
don4331
Senior Airman
I have read 2 things about the Spitfire wing - with emphasis on the Mk.21/22 version.
1. That pilots were experiencing aileron reversal - i.e. when aileron was deflected down, rather than the increase camber increase lift and cause that wing to lift and therefore plane to roll. But rather the whole wing twisted, so in fact less lift was developed and the airplane rolled the opposite direction. Strengthening the wing to prevent the torsion is what delayed the new wing.
2. That at very high speeds, the required angle of attack to fly straight (i.e. along the path you intended, not climbing or diving anymore than intended), that the wing "masked" the radiators, quickly resulting in overheating of the engine. Increasing the initial incidence would seem to be the correct answer for the late Spitfire weighing far more even empty than initial fully loaded, but doesn't seem like correct answer for high speed...
True or another false statement perpetuated over the years?
I dont know, from this they were still working on it 9 years ago, even vibration and noise has an effect NASA Chat: Quest for the Holy Grail of Laminar Flow. However the P-51D was a contemporary of the Me 262, research was already focussing on transonic and supersonic stuff.
drgondog
Major
Pretty close. The 'down aileron in your example, does effectively increase camber (and local lift in the aileron/tip region, but combined with torsion - increases the local angle of attack too much, inducing a stall of the wing. The other wing remains in 'normal' lift mode - even if torsion exists on that wing because the up aileron/camber combination reduces the local AoA below stall AoA. The FW 190 had the issue of high speed roll reversal also, but perhaps due to curious design of 'zero washout' of outer 20% of the LE. The Spit and Mustang LE washout was constant from root to tip, FW from Root to 80% semi-span.
Depends on the altitude. At low altitude/high speed the required CL requires less angle of attack, which could have an effect on the wing mounted radiators. As altitude increases, the density is lower - forcing increasing CL by increasing AoA - thereby 'keeping radiators unmasked'. The underwing radiator for the Spit (or Bf 109) was never entirely successful, but the Bf 109G (and maybe F but my memory fails me) and later were a better design for reducing drag.
We are calling them laminar flow as a general name to distinguish them from everything else
drgondog
Major
That said, High Speed/Low Drag wing a better 'name' for the class of airfoils that pushed the max T/C back from 25% T/C for the modern airfoils of the day.
Hi
The actual problems with the Mk. 21 are well documented in 'The Spitfire Story', which includes five Appendices with copies of some of trials undertaken with this mark, including some of the solutions to the problems that arose. The main text includes the following:
Mike
I just want to say thankyou for your posts, very informative
