improving the 109??

drgondog said:

No possibility of diving more than ~500mph TAS. 800/900 kph reading is result of faulty pitot tube readings in .6-65M compressibility range

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Shortround6 said:

Many airspeed indicators became wildly inaccurate at speeds above their normal range (normal dive speed range) and reports of extreme speeds touched on in combat situations should be looked at in that light. Pilot is not lying, he is relating what the airspeed indicator read. But the airspeed indicator could be off by tens of mph/kph if not a hundred in some cases.

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Yeap. thats why i am not assuring that the me-109 could reach that figure without falling apart, there were 2 or 3 stories of diving at extreme velocity that I could remeber,oner was a finnsh ace to scape of a very agressive la-5 ,other a couple of german pilots.
I think Clostermann also had a recolection of diving at more of 800 kph with his Tempest, probably more plausible that flying a me-109 at that speed.

Shooter8 said:

You are right, but I do not like the word "Production" for 4 hand built prototypes.
Only those planes built in Jigs and production tooling are Production aircraft.
I do note that they have addressed the most important changes to limit losses, which have absolutely nothing to do with aerodynamic performance! They went to heavier and thus performance reducing tricycle landing gear! IIRC, having read someplace that more -109s were lost to landing and take off accidents than to enemy action! I would like more specific data, if anyone here knows more about this factoid/rumor?

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However, you originally said:

Shooter8 said:

"I love that picture and plane but it was never built because it was not that much of an improvement..."

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which is quite misleading. Saying "never built" leads one to assume that the Me309 was one of many Luftwaffe "paper projects", which is not the case. If one was built, it was "built". If four were built, it was "built".

The Me309 was a huge step forward and could have been a capable aircraft if it wasn't underpowered. In relative terms, the Me309 was roughly 200 pounds heavier empty than the P-51 but it's engine rated 200hp less than the P-51.

Regarding the myth about the Bf109's landing gear, there were many other factors that contributed to operational losses than the landing gear. It was the inexperienced pilots who had difficulties with it. As the war progressed, the new pilot's traiing quality declined

The F4U Corsair proved to be very deadly to inexperienced pilots, too.

GrauGeist said:

...
The Me309 was a huge step forward and could have been a capable aircraft if it wasn't underpowered. In relative terms, the Me309 was roughly 200 pounds heavier empty than the P-51 but it's engine rated 200hp less than the P-51.
...

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Just trying to adress this tidbit, Dave. The Me 309 have had enough of engine power. What it did not not have was the favorable wing loading - the wing of 179 sq ft was too small for 7 (seven) guns and the big & heavy V-12 the DB 603, plus how much of the fuel? For comparison, Spitfire was with wing of 242 sq ft, and P-51 was at 235; the Bf 109 was with 173 sq fz, with far lighter powerpant anf armament suite than 309. Fw 190 - early prototypes were at 160 sq ft, it quickly grew to 197 sq ft, and Fw 190 was still regarded as having high wing loading.

Shooter8 said:

Actually, the Me-109 was a very maneuverable plane because of it's "Leading Edge Slats" that gave the smaller wing, much more lift than much larger wings. While it was more difficult to fly at those higher AoA, it could, when flown by so called "Experten", easily out turn the Spitfire at any given speed.

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Excuse me but the slats had nothing to do with maneovrability, they were a device to extend flying envelope before entering in stall and to reduce the landing and take off speed. The Merlin variants of the Spitfire could turn inside me-109s of any variant without much effort, you can read that in any war test report, both allied and german.

Shooter8 said:

<snip>

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Sorry, I was talking to Dave.

Shooter8 said:

This is much more difficult that most of us think. You can't just open the throttle WO also advancing the spark and enriching the mixture and probably the prop pitch as well. During WW-II, except for the Fw-190, no plane had an integrated engine management control and all of these things were done manually. There were specific tasks which had to be done in a specific order, or the engine might blow up before the plane gained one MPH.

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Hoo-boy, the usual rash of mis-information from the "infamous Neoconshooter." See bolded part.

The vast majority of WW II aircraft engines used fixed ignition timing. It was adjusted on the ground by the mechanics and there it stayed. A few engines had a retarder mechanism for starting. Once the engine started it reverted back to the fixed timing.
For example the Allison engines (at least the early ones) were set for the exhaust side spark plugs to fire at 34/35 degrees BTC. The intake side plugs fired at 28/29 degrees BTC and the 6 degree difference was fixed by the design of the Magneto. There is no adjustment in flight. The Allison did get a retarder mechanism in some later models, however the mechanism was arranged so that full advance was reached at 1400rpm and above.

If the engine is already set to "Auto-rich" (and it should have been in combat areas, auto rich being the position of choice down to 27in MAP and 2100-2280rpm) then no further fiddling with the mixture control is needed unless the plane has a full rich position and that was often reserved for special conditions, like engine running rough after a long gliding approach to a landing, not full speed.

Some US planes got integrated manifold pressure (throttle) and propeller speed controls., Increasing the throttle (manifold pressure) automatically increased the RPM setting on the prop. This was fitted to at least late model P-40s (N-20 and N-25s) if not other aircraft. Perhaps some P-47s got something similar? Not the full control some of the German planes had but a useful simplification of controls.
The FW 190 may have been the first (BF 109?) but was not the ONLY aircraft with single stick control. Not sure what what late war British aircraft may or may not have had.

The word "placard" is not used by most people to mean where the data came from.

Placards in aircraft are warnings, numbers, and classifications to remember. There is no placard with the maximum speed on it. The maximum speed is denoted by a red line on the airspeed indicator, sometimes on the PFD/MFD these days. The aircraft data plate usually states the manufacturer, type, serial number, and sometimes but not always the date.

I have seen placards for maximum crew eight, the classification of the aircraft (particularly experimental), weight allowed in baggage areas, and the like, but have never seen one for maximum speed or range. Those numbers come from the pilot's operating handbook that, for military planes, also usually has range and mission-planning tables.

Set of Placards for a P-51 Mustang as sold by Pioneer Aero Service.

Airspeed indicator for Cessna 150 with color coding.


Modern P-51 airspeed indicator. Original ASI dials didn't have knots.


under Limited Type Certificate LTC-11-5 P-51s are required to have an airspeed indicator marked in MPH so as to correspond with cockpit placards, flight manuals and technical data as issued by North American Aviation and the USAF.

Over the 100 plus years that people have been flying planes with instruments (and actual cockpit walls) how information has been displayed to the pilot or what information has been required has changed.

A 30-100+ page manual is NOT a placard. And strangely, many aircraft flight manuals/handbooks do not list max level speeds or climb rates. Or not so strange, they are not not needed for the safe operation of the aircraft. Safe speeds for lowering flaps or landing gear are, stall speeds are, never exceed dive speeds are and so on.

Shooter8 said:

I am also a big fan of the P-40! In actual combat, it was a very much better plane than most of it's contemporaries because of it's combat persistence. The ability to trade cruise speed for range meant that it could fly at higher speed longer. In a particular scenario such as the BoB, the extra range at combat speed would have allowed the >50% of interceptions that could not find their targets to attempt two or more additional interceptions. If half of those "extra" interceptions resulted actual contact with the enemy and shoot downs at the same ratio as historical numbers, then the Germans would have lost many more planes than they did in real life.

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Except that if teh British relied on the P-40 for the BoB they would have lost - they wouldn't have got them in time.

Plus the P-40 only had two 0.50" mgs, which may have meant they would have potentially missed more often.

Also, range was increased by reducing cruise speed, not increasing it.

And, if I'm not mistaken, the limiting factor for interceptions was ammunition, not fuel.

Timing was bad as the first Tomahawks (ex-French)are built in June of 1940 but a Tomahawk in Buffalo NY isn't much good. First ones are unloaded in England in Sept 1940.
The P-40s carried more ammo per gun than the two British planes and the ones the British got had two guns in each wing in addition to the fuselage guns. It also could carry more fuel.
HOWEVER, it couldn't climb very well. Performance numbers at P-40 Performance Tests

Look good but they are at 6835 lbs and that is just too light for a P-40 in real combat kit. Even with rudimentary self sealing tanks and armor a P-40B went 5990lbs empty equipped (guns and radio fitted) and could go 7350lbs with only about 19 US gallons of fuel in the fuselage tank (or about 100 IMP gallons total). Something has to give to get the plane down to the 6800lbs. Guns, ammo fuel?

A P-40B with full internal fuel could weigh over 7600lbs.

The idea that extra endurance might enable an aircraft like the P-40 to "attempt two or more additional interceptions" is nonsense and demonstrates an ignorance of how the air defence system developed by the British in the 1930s operated and an ignorance of the speeds, times and distances involved.
The British didn't just happen upon fighters with the endurance of the Spitfire or Hurricane, they were requirements issued for the aircraft to be the sharp end of an integrated air defence system. These were air defence fighters, the 'problem' of endurance only arose when it was attempted to use them in roles for which they were not designed.
Cheers
Steve.

Extra endurance could have been quite useful, Extra endurance being another 20-30 minutes over England, not hundreds of miles over France and low countries.
However that extra endurance could only be bought at the cost of speed or climb or turning circle or field performance or..... OR a combination of these factors.
For instance a P-40E at 7500lbs needs 1850ft (617yds) to clear a clear a 50ft obstacle on take-off from a sod runway. Or 37 more yds than a Hurricane with a two blade fixed pitch prop. The P-40 figure is also for 0 degrees. Add about 10% for ever 10 degrees C or 20 degrees F.
P-40E had 1150hp for take-off, not the 1040hp of earlier P-40s and certainly not the 880hp of a Hurricane I or Spitfire I and that is when they had variable pitch props. Using fixed pitch props called for lower engine rpm (power) for take-off.

Having an extra 50% endurance and an extra 20-50% ammo load doesn't do a lot of good if you can't get the plane to take off from existing airfeilds.
And you still had to put up with the 38lb tire pressure rule. Add a few hundred pounds of fuel and ammo and you needed bigger wheels/tires which needed bigger wheel wells which needed...........

IF the British could have magically gotten fighters that had 50% more endurance using existing engines, propellers and airfeilds I am sure they would have used or bought them.

Extra endurance is always useful, but it would not have increased interception rates in the BoB. The idea that by somehow flying around for an extra 20-30 minutes a fighter might have achieved more interceptions or been re-directed to make them, simply doesn't fit the facts of the Battle.
The Luftwaffe typically flew from bases roughly 50-80 miles away from the 11 Group airfields it was attacking, less attacking Channel shipping, slightly further to London. If the initial interception was missed there was rarely time to make another before the attackers were gone. Chasing after a formation, particularly one 'diving for France', given the relative difference in speeds was a fruitless task, ditto for flying standing patrols in the hope of finding the enemy. Patrol lines were flown, but by aircraft positioned on the known and plotted track of the incoming enemy formations. They were positioned in what was considered the best place to make an interception, they still failed to do so on many occasions.
The radar only looked out to sea, not inland. Once the enemy formations had crossed the coast they were plotted by the (Royal) Observer Corps. To ensure interception the intercepting fighters had to be positioned a lot closer to the enemy than most appreciate, certainly less than five miles, in most conditions around three miles from their target. This was a difficult thing to do and having an extra 20-30 minutes of fuel would not make it any easier. Most likely the interceptor would still be flying around looking for the enemy whilst he was landing back at his bases in France!

I have also seen it proposed that increased endurance would have allowed RAF fighters to pursue retreating Luftwaffe aircraft across the Channel. Some did in fact do this despite being expressly forbidden from doing so. Individual aircraft doing so were vulnerable to counter attack by the Germans who, not being stupid, on occasion positioned units to do precisely that. Covering a withdrawal is pretty standard military practice

Cheers

Steve

The missions flown by the RAF in the BoB changed day to day, sometimes squadrons could be scrambled and placed to intercept an incoming raid with height and sun advantage in others they were actually taking off through falling bombs. In most accounts I have read my memory is of the pilots struggle to get height, I doubt any pilot would want the extra weight of fuel and ammunition just to have a longer mission, it increased your chances of being bounced which was how most losses on both sides occurred.

The other consideration is the critical altitude of the engines. The P-40's was ~5,000ft lower than a Spitfires, which may have been vital in the BoB with the altitudes the LW flew.

That's very interesting, Shortround. We have three P-51s and only one of them is Limited. That would be Steve Hinton's P-51D "Wee Willy." I've never been in it's cockpit. The other two P-51s are Experimental Exhibition. None of the birds I have worked on have speed placards that I noticed, but we also have many of the placards partially removed and stored for replacement when restoration has been completed. That includes a B-17G (the instrument panel is not complete yet), a Bell YP-59A, a North American O-47, a Grumman OV-1 Mohawk, and the Hispano Ha.1112 Buchon. I did not see a speed placard in the Ha.1112 and I helped with the cockpit. Right now the entire cockpit in the YP-59A is apart and out of the airframe for final painting and reassembly. Perhaps a speed placard will magically appear later, I don't know and won't predict.

The speed placard in the Limited category bird is not on the instrument panel, but is located on the left side of the cockpit just above the armrest. It is way to the left below.



Perhaps that is why I never noticed it when in the other P-51s. Don't know if it is required in the Experiment Exhibition birds or not. The speed placard is quite interesting to me since the 505 mph IAS is only accurate at 5,000 feet. AT 10,000 feet it is 480 mph and it decreases down to 260 mph at 40,000 feet. If you forget that and push over from 40,000 feet and try to get to 505 mph IAS, you will get a nasty surprise, possibly fatal, so it doesn't really make sense to have it there, at least to me.



The above (from the P-51D POH) would make a LOT more sense, but also takes up a lot of real estate, so it might not be practical ... no place to put it.

Few operate a P-51 in the IFR flight levels these days, so maybe it isn't really important after all. Who wants to waste P-51 time flying straight and level? Nobody I know, at least on local flights. Fighters weren't made for straight and level. Most of the ones I see flying every weekend are frolicking between sea level and 15,000 feet or so on local flights. If you have to go cross country in a P-51, perhaps it still makes sense to get high. I'll ask. We fly many fighters between California and points north and east. We even occasionally send warbirds to the east coast for an airshow.

I asked once about the F-86F we have and was told they were cruising at around 17,000 feet or so going to Tucson for the Heritage Flight annual meeting / training.

Cheers.

It was a system and a system has to take into account the capabilities of it's parts. Longer endurance interceptors could have been useful, but not critical.
It also takes months sometimes to adopt and implement new equipment into a system. Patrol areas or distances for a particular squadron to make an interception were made taking into account the endurance of the existing aircraft. Patrol areas or having controllers vector in squadrons from a few miles further away could have been changed had higher endurance aircraft been available.
Some of the was done by "feel". Controllers knowing from experience what to expect from the squadrons. Like if they had already been in the air for 3/4 hour then they didn't have much fuel to chase anything. Keeping the pilots and planes safe to handle a later attack took priority over getting a few kills on retreating formations.
Endurance also translates into more combat persistence. Like one minute at combat power being worth 2-4 minutes of "cruise" so a plane with more fuel may be able to get in a few more firing passes, ammo supply permitting even if time in the air was only 10 minutes longer than a standard "British fighter".

The system was designed/evolved the way it did due to the capabilities of the sensors (radar and ground observers) the control set up(plotting boards and radios) ad the aircraft. It worked. improving one aspect may well have given better results but that only changes the score, not the outcome. And improved aircraft would have taken a number of weeks for the controllers to handle effectively. A learning curve if you will, to see what they could do with the improved capability. AND what they couldn't do.

The system was being designed and implemented while the fighters were still being fitted with fixed pitch props. Doesn't mean that they should have stayed with fixed pitch props. But it does mean that you can't wave a magic wand and claim that fighter XXX would have been so much better the British pair if other aspects of fighter XXX performance meant it couldn't meet other British requirements.

Hurricane and Spitfire might well have been designed differently if the British had used constant speed props in 1936 and had 700yd concrete runways. They didn't and the capabilities of the aircraft have to be looked at in the light. What kind of speed and climb (and carrying the heaviest armament of the time) could they get out of the engine/s and props of the time and still use the existing airfields?
Not what engines and fuels showed up 4-5 years after the prototypes first flew.

wuzak said:

The other consideration is the critical altitude of the engines. The P-40's was ~5,000ft lower than a Spitfires, which may have been vital in the BoB with the altitudes the LW flew.

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It was critical. Combined with the weight of the P-40s it meant that the P-40s had no business trying to fly combat mission at high altitudes ( high being some where around 20,000ft and up)

pbehn said:

The missions flown by the RAF in the BoB changed day to day, sometimes squadrons could be scrambled and placed to intercept an incoming raid with height and sun advantage in others they were actually taking off through falling bombs. In most accounts I have read my memory is of the pilots struggle to get height, I doubt any pilot would want the extra weight of fuel and ammunition just to have a longer mission, it increased your chances of being bounced which was how most losses on both sides occurred.

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Yes, and the RAF's interceptors were a compromise between all the various factors required, principally performance, armament and endurance.
Cheers
Steve

Shooter8 said:

Part two; Because British testers were not familiar and experienced with LE Slats they did not duplicate the true performance of the plane and because of the sudden lurch as the slats deployed, they were afraid, or reluctant to enter that part of the envelope.

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I read somewhere on here that the top aces had the same opinion with other German pilots, some got "windy" (to use an RAF phrase) when the slats deployed but for the top guys that just marked the start of the real flying.