Spiteful

[Civettone]

You're talking about the Spiteful?

The data I have suggest that it didn't have a long-range capability. To me, it's simply the successor of the Spitfire. Development started rather early but was always put on low priority. The British - more than others - upgraded existing designs rather than start with a new one. Worked well in WW2...

Kris

 

[Morai_Milo]

Spitful could carry both 90gal and 170 gal drop tanks.

 

[bigZ]

You're talking about the Spiteful?

The data I have suggest that it didn't have a long-range capability. To me, it's simply the successor of the Spitfire. Development started rather early but was always put on low priority. The British - more than others - upgraded existing designs rather than start with a new one. Worked well in WW2...

Kris

Sorry went a bit of topic. No I did mean the Spitfire. Apparently the prototype was an utter failure and quietly shelved. My information is second hand and was hoping for confirmation.

 

[davparlr]

There are a lot of reports of very fast aircraft in the latter days of WWII. However, the planes of that era typically had airspeed indicators that only provided indicated airspeed (IAS). Some may have been corrected for installation errors (calibrated airspeed-CAS). Probably none had been corrected for compression (equivalent airspeed-EAS). And probably none had outside air temperature which is necessary to calculate true airspeed (TAS). As a result of all of these errors, the indicators of these aircraft were woefully inadequate to generate an accurate TAS and pilot reports other than "that was fast" should be suspect. Unless, of course, the plane was tested in a controlled enviornment with proper instrumentation.

The world's fasted piston engined aircraft over 3 km is an F8F with a non-standard R3350 engine that generated 3800 hp with a speed of 850 km/hr (528 mph). Over a longer course, a P-51D holds the record with a non-standard Merlin that generated 3000 hp with a speed of 832 km/hr (516 mph). You can pretty well predict that these aircraft were stripped of every non-essential pound and every crack was sealed and every bump was removed, and with very small aerodynamic canopys. Also, they probably only had enough fuel to fly the course and land.

With the above information, I believe that, for a piston powered warbird to approach 500 mph in level flight, it would have to be very clean, no racks, and have about 3000 hp. The following planes would probably be capable of reaching close to 500 mph, although I have not seen any test results that would indicate that. With a normal load of fuel and with the warfighting weight, even these would struggle to get close to 500 mph.

XP-72 with 3450 hp
Do-335 with 3600 hp

With 2400 hp, the Spiteful probably would not approach 500 mph.
Two engine aircraft would have to carry a significant more hp due to increased drag. Except, of course, the Do-335 which had tandem engines.

 

[Jank]

The XP-47J with an R-2800C-57 (2,800hp) hit 507mph in combat trim. The secret - It's combat loaded weight was 2,000lbs less than a P-47D and it had a close fitting cowl that presented a more efficient shape.

 

[Smokey]

The Heinkel He P 1076 had a theoretical speed of 546 mph and forward swept wongs, so in theory it would have had a relatively small turning circle.

Heinkel He P.1076

 

[davparlr]

The XP-47J with an R-2800C-57 (2,800hp) hit 507mph in combat trim. The secret - It's combat loaded weight was 2,000lbs less than a P-47D and it had a close fitting cowl that presented a more efficient shape.

I've seen that number too, but I don't know if it is flight test or engineering estimates. I have seen similar data on the P-51H showing a top speed of 487 mph, which was an engineering estimate by North American while actual flight test show only about 475 mph. The XP-47J does have the criteria I suggested, however.

 

[davparlr]

The Heinkel He P 1076 had a theoretical speed of 546 mph and forward swept wongs, so in theory it would have had a relatively small turning circle.

Heinkel He P.1076

A lot of things can be accomplished theoretically. The P 1076 (if it could have been built with those forward swept wings and the engine worked) could probably reach the 500 mph level with its most powerful engine, 2750 hp (it meets my criteria) but I doubt it could go a lot faster. Remember, a P-51D, also an extremely clean aircraft, with a 3000 hp engine was able to make only 516 mph, a record that still stands for the distance.

Also, the fasted propeller driven aircraft in the world was a Russian Tu 114 with speed of 541 mph. This with counter-rotating supersonic props and was jet turbo powered.

 

[Smokey]

Mark XIV - the type 371 was fitted with a Griffon 69 engine rated at 2,375 hp driving a 5 blade propeller. The top speed was 475 mph. 19 were built. Of these aircraft 1 was converted to a Mark XV and 2 were converted to Mark XVI.
Mark XV - Fitted with a Griffon 89 or 90 engine rated at 2,350 hp and driving two contra rotating three blade propellers. The one converted aircraft, RB520, was subsequently used in the development of the Seafang. Top speed was 483 mph.
Mark XVI - The two conversions from the Mark XIV, RB516 and RB518 were fitted with the Griffon 101 engine producing 2,420 hp and a top speed of 494 mph.

http://www.supermarine-spitfire.co.uk/the_spiteful.htm

 

[Civettone]

Davparl, wouldn't you consider the Spiteful aerodynamically more refined and lighter in weight than the P-51D?


And the tandem engine configuration of the Do 335 was aerodynamically inefficient, as acknowledged by the Dornier guys themselves.

Kris

 

[delcyros]

The Meteor issue is an interesting one and certainly there is potential for a more rapid introduction, but I doubt that it could have been avaiable that early. One should not forget that the US provided the tooling tech necessary to mass produce jet engines to the UK in early 44.
The 490 mp/h are also somehow optimistic. I can recall in between 768 and 770 Km/h at 3000m (477-478 mp/h) in clean configuration after tail modifications in late 44. Below or above this altitude, the speed curve drops off significantly.

 

[delcyros]

The theoretical estimates of speed should be taken with a serious grain of salt. This is true for all ww2 nations estimates which achieved higher speeds than Mach 0.75. In Germany, f.e. (I could examplify the US or Britain as well but I am particularely more familar with the RLM issues) every company used it´s own mathematical system, which tends to produce contradicting estimates. The full problematic of transsonic speed calculations were solved in late february 45 by the DVL and any earlier design proposal was prone for to high estimates.

 

[Hop]

Talking of spit development. Wasn't their an atempt to significantly improve the the Spits range for bomber secort which ended in failure?

There were quite a few methods used to improve the Spitfire's range.

The first was to fit drop tanks, of 30, 45 or 90 gallons. A 170 gallon tank was used on some ferry flights and for recce Spitfires.

Second was increasing the lower forward fuel tank by 10 gallons. This was standard on Griffon Spitfires and Spitfire VIIIs, and common on other late production Spitfires.

Third was fitting tanks in the wing leading edge, of up to about 18 gallons each.

Fourth was fitting a rear fuselage tank. This was first done on Spitfire Vs for ferry to Malta, when a 30 gallon tank was fitted. In 1944 and 1945 some Spitfires were fitted with rear tanks of up to 75 gallons.

The most fuel a Spitfire could reasonably fly with would be a Spitfire VIII with 95 gallons in the main tanks, 28 in the wing tanks, 90 in a drop tank, and up to 60 in a rear tank, for a total of 273 gallons. The first Spitfires had started out with 85 gallons.

Such long ranges were rarely required of Spitfires, though. The recce aircraft, which did need long range, were equipped with lots of extra fuel, for example the PR XIX carried up to 257 gallons internally.

The only "attempt" I know of to equip the Spitfire as an escort was by the USAAF. Two Spitfires were modified in the US, having tanks put in to their leading edge, and wing drop tanks added. The modifications to the wing for the leading edge tanks were thought to have weakened it (although slightly larger tanks were routinely fitted to Spitfires in production). The aircraft were flown back across the Atlantic to Britain.

There was no reason for the Spitfire not to have greater range. The British didn't really require it in most cases, and when they did Spitfires were equipped with extra tanks. The US seriously considered using the Spitfire as an escort, but by the time they would be available with long range tanks the Mustang was entering service as an escort fighter, and Spitfire production wasn't high enough to fulfil all the demands placed on it.

Here's the consumption figures achieved under Australian testing of the Spitfire VIII with Merlin 66:

This aircraft had 123 gallons internally, and a 90 gallon drop tank. The drop tank remained attached at all times, hence the "ferry" designation.

 

[davparlr]

Davparl, wouldn't you consider the Spiteful aerodynamically more refined and lighter in weight than the P-51D?

Since the P-51D that set that particular record is tail number N5410V, which is Dago Red, a rather famous and highly modifed racer, the answer is, no, until all the things that was modified on Dago Red was applied to Spiteful.

And the tandem engine configuration of the Do 335 was aerodynamically inefficient, as acknowledged by the Dornier guys themselves.

Kris

I don't know, you may be right. The overall design concept is aerodynamically sound with a puller and a pusher prop and the aircraft looks clean. The detail execution of it may be inefficient. It does seem strange that the Do 335V-1, with 3500 hp available was only capable of reaching 455 mph. Also, tandem engines always seem to pose cooling problems, which may have been a problem here, too.

 

[davparlr]

The Supermarine Spiteful

That site usually has flight test or manufacture data to support its statements. In this case it does not provide that. I would like to see that before I would conclude this data is accurate.

 

[pbfoot]

Every pound added whether its fuel, oxygen, weapons etc or even the weight of the paint affects the useful load an aircraft its coming up with a balance that makes or breaks the aircraft . The spit could never be a long range fighter without sacrificing one of its other attributes

 

[Civettone]

Davparlr,
I didn't notice the P-51 was modified that way.

As to the Do 335, the problem was that the front prop couldn't achieve its maximum efficiency because the air flow interrupted that of the other engine ... or something like that

But it's obvious when you look at the next Do 335 designs: they abandoned the tandem engine layout in the P 247 and P 252.

Kris

 

[davparlr]

Davparlr,
I didn't notice the P-51 was modified that way.

What you can see is the small flaired-in canopy, the high gloss reflection in the wing which indicates a highly polished finish, and the advanced, and modern, wing-tip flairings. What you can't see is the efforts that was spent to lighten the airframe and the detail that went into eliminating any source of drag such as gaps, uneven alignments, etc. in order to achieve the cleanest airframe. Also, the I believe the wings had been clipped. As it was, the baseline P-51D in military trim was one of the cleanest fighters of the war as indicated by the hp required to generate speed at sea level (1640 hp, 375 mph), with only the Fw-190D coming close (1750 hp, 380 mph).

As to the Do 335, the problem was that the front prop couldn't achieve its maximum efficiency because the air flow interrupted that of the other engine ... or something like that

But it's obvious when you look at the next Do 335 designs: they abandoned the tandem engine layout in the P 247 and P 252.

Kris

Good information, and reasonable.

 

[Kurfürst]

Here's the consumption figures achieved under Australian testing of the Spitfire VIII with Merlin 66:

This aircraft had 123 gallons internally, and a 90 gallon drop tank. The drop tank remained attached at all times, hence the "ferry" designation.

It should be noted that Hop usually waves about this leaflet from an Australian archives, which is claiming 10 miles per gallon achievable. That of course, is by far the highest mileage you`d find for any Spitfire test - it appears to be a single abberant test result, with dozens of other fuel consumption trials showing around 6-6.5 mpg being realistically achieavable. Hop knows those very well.

Here`s for the Mk IX. Mk IX and VIII had the same engine :

These full endurance trials showed 6.76 mpg being achievable at 20000 feet, 1800 rpm.

If you`d add up the claimed mileage in Hop`s paper with the fuel tankage, ie. 10 mpg and 120 gallons available, this would give you something like 1200 miles (!!!) of range for the Spitfire. If this would be true, there would be never any need for the Mustang as Spitfires would easily reach out to Berlin and back. Nonsense, of course, and all MkVIII data sheets give only 740 miles or so range, which points to the 10 mpg data is simply result of an abberant test, perhaps, but agrees well with the ~ 6.5 mpg given everywhere else.


The original comment on the Spitfire`s lack of penetrative range is quite correct. Despite many attempts, the Spitfire, as the war progressed, become increasingly a defensive fighter, lacking the range for any serious escort job.

Simply adding fuel droptanks did not solve the problem, since your penetrative range in any case is determined how much internal fuel you`re left with after you dropped the fuel tank. In other word, you can`t use practically a 90 gallon droptank to bring you over to enemy territory, if all you have is 85 gallons (some of which you`ll use up quickly during combat, where fuel consumption skyrockets at max power) to return on.

The rear tanks, fitted irregularly to some planes at the very end of the war were similiar to droptanks, as they could be used for ferry (one-way) missions only, like Malta. The reason was that with the rear aux. tanks the Center of Gravity shifted so far back that the plane was outright difficult and dangerous to fly, not to speak air combat. Therefore the rear tank, like a droptank, had to be emptied first, and then return on the normal internal tankage, again 85 gallons on the vast majority of Spits.

The third factor was that the rapidly increasing fuel consumption of the Merlin made the Spitfire shorter and shorter ranged. The confidental document titled 'Development of the Spitfire Fighter' from the Australian archives gives some idea :

The Spitfire I, while cruising very slowly - hardly an option over enemy territory - could go as far as 575 miles at 188 mph, but only 350 miles if it travels at 250 mph.

The Spitfire V was shorter ranged, at slow economic cruise it would manage 480 miles at 185 mph, and 335 miles at 310 mph cruising speed.

The Spit IX was even thirstier, at economic cruise it would manage 450 miles on slow economic cruise, as seen above.

The Spit VIII was the only variant which had some range at least, with the internal fuel being increased by 50% to 120 gallons with 740 miles being possible at slow economic cruise, and much less if any reasonable speed was maintained. However few were build and most of those went either to the PTO or MTO, where with the large overseas missions the short range of the Mk V or IX would simply not do.

Enter the MkXIV and the Griffon engined fuel hogs.. range was down again, fuel tankage was 120 gallon, as in the MkVIII, but the Griffon engine was not any shy using it up... at enourmous rates. The range at an economic, slow cruising range was down again to about ca 450 miles. That is, with 50% more fuel carried than the Mk I, and having 100 miles less range. That of course would refer to the luxury of cruising at slow speed over enemy territory, asking to be bounced by an enemy fighter.

Of course this is on interal fuel, but for escort or any two-way mission, it makes sense to look at the droptank range. The absolute maximum range of a mission was defined by the range of what you could get back on your limited internal tankage, ie. after dropping your external tank when engaged and using up considerable amounts of fuel at high power during air combat. A % of allowance had to be also given for navigational etc. errors, or just circling above your own airfield and wait for your turn to land.

There`s a good reason why US escort fighters were introduced, and while they featured very large internal fuel tankage.

 

[Hop]

What Kurfurst knows well is that the page he posted is for a test on a Spitfire IX with Merlin 61. The Merlin 61 was rather different to the Merlin 66, the engine which powered most Spitfire VIIIs/IXs/XVIs.

The Merlin 61 had a slightly different supercharger, but more importantly it had an SU float carburettor. The Merlin 66 had a Bendix Stromberg injection carburettor.

The Australian test is for a Spitfire VIII with Merlin 66.

If you`d add up the claimed mileage in Hop`s paper with the fuel tankage, ie. 10 mpg and 120 gallons available, this would give you something like 1200 miles (!!!) of range for the Spitfire. If this would be true, there would be never any need for the Mustang as Spitfires would easily reach out to Berlin and back.

The problem is escort range is typically one third of maximum range, which means you need about 1800 mile range to escort bombers to Berlin and back. And you don't want to cruise at 160 IAS, either, because you'll be a sitting duck over Germany at that speed.

The rear tanks, fitted irregularly to some planes at the very end of the war

From the Spitfire IX/XVI manual:

Later production Mk IX and all Mk XVI aircraft mount two additional fuel tanks with a capacity of 75 gallons (66 gallons in aircraft with "rear view" fuselages), they are fitted in the rear fuselage.

1,054 Spitfire XVIs were made.

The rear tanks were also fitted to the Spitfire XIV, possibly other models as well.

were similiar to droptanks, as they could be used for ferry (one-way) missions only, like Malta.

Wrong. Source for this claim?

The reason was that with the rear aux. tanks the Center of Gravity shifted so far back that the plane was outright difficult and dangerous to fly, not to speak air combat. Therefore the rear tank, like a droptank, had to be emptied first,

In other words, exactly like the Mustang. Both had to use most of the fuel in the rear tank first. The RAF Spitfire IX manual notes:

"When the rear fuselage tanks are full there is a very marked reduction in longitudinal stability, the aircraft tightens in turns at all altitudes and, in this condition, is restricted to straight flying, and only gentle manoeuvres; accurate trimming is not possible and instrument flying should be avoided whenever possible."

The RAF Mustang III (P-51B) manual notes:

"Stability.—Except when earning full fuselage tank, the aircraft is stable longitudinally, laterally, and dircc-tionally. When the fuselage tank is full, the aircraft is longitudinally unstable in all conditions of flight, and tends to tighten up in turns; until at least 40 Imp. gallons (48 U.S. gallons} have been consumed from the fuselage tank, no manoeuvres other than very gentle turns should be attempted."

Regarding aerobatics, the Spitfire manual:

"Acrobatics are not permitted when carrying any external stores (except the 30-gallon " blister " drop tank) nor when the rear fuselage tanks contain more than 30 gallons of fuel, and are not recommended when the rear fuselage tanks contain any fuel."

Mustang manual:

"Flick manoeuvres arc not permitted. When carrying bombs or drop tanks, or with fuel in fuselage tank, aerobatics are prohibited."

As you can see, the restrictions on the Spitfire with rear fuel tank are not quite as bad as for the Mustang, the Mustang is prohibited from any aerobatics with any fuel in the rear tank, the Spitfire with more than 30 gallons in the rear tank.

and then return on the normal internal tankage, again 85 gallons on the vast majority of Spits.

Depends on the Spitfire. Most Spitfires had only 85 gallons internal because that's all they needed. Those that needed more fuel, like the Spitfire VIII, the Spitfire XIV, the recce Spits, got more tankage.