Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
An interesting post-war development was Kurt Tank's design for Argentina, the Pulqui II.Regards,
Magnon
The Me 262 controls became very stiff at speed:
...This balance is in addition to those already noted as being set in the elevators themselves, and may be a late modification. Reports from abroad have indicated that at speeds over 500 mph. the ailerons and elevators of the 262 become extremely hard to move and that an extendable control stick designed to give increased leverage had been developed. However, no such stick, or provisions for its installation could be found on the craft studied, and it is held possible the mass balance just discussed has been utilized in its stead...www.enginehistory.org/German/Me-262/Me262_Airframe_2.pdf
Regards,
Magnon
Magnon - neither post proves anything. It is easy for controls to be boosted to overcome 'slow roll', 'slow pull out' etc. It is not so easy to keep wings, tails, etc from deprating when those 'boost' devices are installed.
The Mustang had rudder reverse 'boost' to make rudder forces greater during high q manuevers to make it harder for the pilot to destroy the airplane during high asymmetric manuevers (slow rolls, turns during a dive, etc.)
BTW, the slats have only two possible values - 1.) low speed speed wing tip control and 2.) slightly reduced drag over a twisted wing leading edge.
The MiG had a sevre pitch up moment in Mcr causing stress leading to possible tructural failure.
Like the 109 it was stiff in high G turns, but like the 109, could be overcome by a strong pilot - BTW the airplane doesn't 'stay' in 400-450 kts envelope very long with that T/W ratio - ditto the F-86 - or the Me 262 - or the original Meteor - for the same reasons
Thanks Drgndog,
What I was trying to say was that it is not black and white. If I understand your post correctly, you're saying much the same thing.
It seems the problem wasn't really satisfactorily resolved until several years after the war with the introduction of powered controls with feedback.
Regards,
Magnon
The following chart may be of interest in assessing the Me 262's turning performance. Hans Fey reported that was a weakness of the Me 262:
"The Me 262 is relatively slow in turns and movements. It cannot, for instance, Split -S in less than 9000 - 12000 feet."
See http://www.zenoswarbirdvideos.com/Images/Me262/ME262PILOTDEBRIEF.pdf
From what he said, it would seem reasonable to infer that at a flat out 500 knots, the turn radius was 6,000 ft, which would approximate to less than 5 Gs maximum allowing for adding 1 G on pull-out. This would explain why the Me 262was not able to out-turn a Mosquito (in six passes).
For the lower value, the corresponding average G is 5.8, giving 6.8 maximum on the bottom of the pull-out, still not great for a dogfighter.
Regards
Magnon
I can't find figures giving a direct comparison between the Meteor F3 and the Me 262, but the following gives the F4 comparison:
Me 262 Structural airframe G limits
+7g @ 440mph
-5g @ 410mph
worldaccessnet
So, admittedly the figures are for the more robust F4, but this is a very high margin.
Regards,
Magnon
taking Data from IL2-1946 flight sim as true numbers, funny
maybe got some from willie's factory, or even from stormbirds.com?
ps: at-5G , the pilot is dead!
You still didn't answer my question yet:
how could a MK3 turn faster as the 262 if the MK3's ailerons couldn't be moved at speeds above 400mph? (see operationnal repport on the mk3) or maybe you don't understand my question ,what could be possible because English is my fourth language and i have difficulties to write what i mean, and then i will paraphrase the question : how much time does it take in the mk3 if a pilot want to make a 180° tunr from the moment he start to move his stick on the Y-axis?...i bet it would be very long if the pilot isn't able tu push the stick enough to bank the plane for the turn....
taking Data from IL2-1946 flight sim as true numbers, funny
maybe got some from willie's factory, or even from stormbirds.com?
ps: at-5G , the pilot is dead!
You still didn't answer my question yet:
how could a MK3 turn faster as the 262 if the MK3's ailerons couldn't be moved at speeds above 400mph? (see operationnal repport on the mk3) or maybe you don't understand my question ,what could be possible because English is my fourth language and i have difficulties to write what i mean, and then i will paraphrase the question : how much time does it take in the mk3 if a pilot want to make a 180° tunr from the moment he start to move his stick on the Y-axis?...i bet it would be very long if the pilot isn't able tu push the stick enough to bank the plane for the turn....
The quoted figures come from Me-262
It also indicates: 'The entire aircraft has a giant sticker on it that reads "Caution: FRAGILE".'
The writer of this has done his research well.
If you want confirmation of this, it is well and truly borne out by the Messerschmit test pilot Hans Fey's comments on http://www.zenoswarbirdvideos.com/Images/Me262/ME262PILOTDEBRIEF.pdf
In terms of what an aircraft should be designed for, see:
What can be dangerous are high accelerations; expressed as multiples of gravity, or g's. In pulling out of a dive, for example, a pilot may be subjected to an acceleration as high as 9 g. If a force of 4 to 6 g is sustained for more than a few seconds, the resulting symptoms range from visual impairment to total blackout... While facing backward in a seated position, properly supported human test subjects have been able to tolerate a deceleration force of 50 g without severe injury.Acceleration of Blackout in Fighter Pilots
The acceleration that causes blackouts in fighter pilots is called the maximum g-force. Fighter pilots experience this force when accelerating or decelerating quickly. At high g's the pilots blood pressure changes and the flow of oxygen to the brain rapidly decreases. This happens because the pressure outside of the pilot's body is so much greater than the pressure a human is normally accustomed to. One human body handles g's different then another.
Regards,
Magnon
What is the roll rate of the Me 262? I haven't been able to find the statistics for the Me 262.
It seems the F3 Meteor was about 40 degrees per second at 300-400 mph, the F4 about 85 degrees per second, and the Lockheed F80 about 135.
The controls were limited to prevent the pilot from overstressing the structure. The Meteor structure was much more robust than the Me 262.
As an indication of the relative problems of the two aircraft in terms of manoeuvring:
• The CFE indicates for the Meteor "aerobatics must not to be performed at an all up weight in excess of 12,300 lb." (The fully loaded all up weight was given in the report as 12,614 lb)
• On the other hand, the Me 262 Handbook says categorically "no acrobatics are to be performed" and "no spins are to be attempted"
• This is backed up by Messerschmit pilot Hans Fey who says that acceptance pilots wouldn't carry out a roll or a dive in a Me 262 unless they were forced to.
• In terms of general airworthiness of the two aircraft, in the context of Fey's warning of the danger inherent with the Schwalbe in terms of diving and rolling, nothing is mentioned about spinning. On the other hand, the CFE report conveys feedback from the Gloster trials: "The Meteor has not been cleared for practice spinning but, if the foregoing instructions are followed, the pilot should have no difficulty in recovering from an accidental spin"
-Yes, that's what i mean, it's even worse as this is a kind of manual from "acces high" game, even worse than il2 in this case
-I wrote -5G not +50G's, there is a big difference, and i do know the differencies between individuals and G's. nothing new here.
-Rollrate 262: me neither, lol. Maybe more luck at stormbirds.com?
If you say so, my question was: the time needed for the pilot at 400mph to move the ailerons into position to get the roll of 40°/sec (your numbers)
If you can answer that, you'll know the real time needed for the roll.But that points cerntainly depends of the pilot's arms size...Hasta la Vista Ailerons!
Nothing in the RAF evaluation repport about that.
If yo have an airplane flying 150mph faster than any other airplane, as pilot, do you really want to start a dogfight like in 14-18? You don't need it, you speed is a bigger advantage. Why would you spin the plane? that would only mean you're a bad pilot and you loose all your energy and what also means you're already dead if ennemy fighters are next to you...
Please read again the repport http://www.wwiiaircraftperformance.org/meteor/Meteor-CFE.pdf and check points 68-73-74-76-79!!!!-90(table)-93-115 and conclusions 137-139-140
The MK3 was a bad plane , at least bad enough for aerial combat and for it's pilot comfort. Take a look at the 262's cockpit and the meteors Cockpit, just the same as the comparaison between a spitfire's cockpit and the wurger. (i could even use the exemple between the spit and the p51 that also had a nice done cockpit)
A lot of garbage badly placed in the meteor and everything ergonomicaly and logicaly placed in the 262. If you're a pilot and the airforce gives you bird where the workload to fly the plane is nihil (almost) and another where you have to look in crazy ways to check the instruments, because a lot of them is invisible, in what plane will you fly better?
The evaluation was quite critical in some areas, but overall said the fighter was very capable; read the conclusion.
Also:
Nose Wheel Shimmy
192 ATI-61 C
Nose wheel shimmy on the Me 262 turbojet fighter bomber (in German). Me-262-970, May 1944 = ATI no. 32631
Short report on nose wheel shimmy tests of the German Me 262 (V-9). Report concludes that a definite amplitude (initial deflection), a certain amount of pivotal friction, and a certain taxiing speed must be produced in order to cause shimmy. Theoretically, this means that the nose wheel should be locked completely to prevent shimmy. The maximum wheel deflection during taxiing is 13 to 15 degrees when the critical shimmy speed (about 31 mph) is reached. It is proposed to install a hydraulic damper on the V-9 model.
Landing Gear Weakness197 DC-27 C
Fend, Contributions to eliminate the difficulties encountered with the landing gear of the Me 262 (in German). ME-262-148, Oct. 1944 = CADO no. 45 2138-1 = ATI no. 19072
This is a report on measures for prevention of damage to the landing gear of the German Me 262. Results of investigations during flight and on the test field indicated that the shock absorbing qualities of the hydraulic strut heretofore used in the Me 262 are unsatisfactory because of the effect of lateral forces. The latter effects increase the loads above the amount previously expected. As a consequence, damage results due to overloading of the tires, the strut and mounting plates. This overloading can be eliminated by modification of the landing gear (hydraulic pressure, quantities of oil, damping return stroke, fork linkage, wheel drive, etc.). The various types of damage are thoroughly discussed and the probable causes analyzed.
[B]http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA076003&Location=U2&doc=GetTRDoc.pdf[/B]
The CFE pilot's report was nothing like as critical as Hans Fey. Read http://www.zenoswarbirdvideos.com/Images/Me262/ME262PILOTDEBRIEF.pdf .... Shocking...
Regards,
Magnon
The MK3 was a bad plane , at least bad enough for aerial combat and for it's pilot comfort. Take a look at the 262's cockpit and the meteors Cockpit, just the same as the comparaison between a spitfire's cockpit and the wurger. (i could even use the exemple between the spit and the p51 that also had a nice done cockpit)
A lot of garbage badly placed in the meteor and everything ergonomicaly and logicaly placed in the 262. If you're a pilot and the airforce gives you bird where the workload to fly the plane is nihil (almost) and another where you have to look in crazy ways to check the instruments, because a lot of them is invisible, in what plane will you fly better?
The evaluation was quite critical in some areas, but overall said the fighter was very capable; read the conclusion.
Also:
Nose Wheel Shimmy
192 ATI-61 C
Nose wheel shimmy on the Me 262 turbojet fighter bomber (in German). Me-262-970, May 1944 = ATI no. 32631
Short report on nose wheel shimmy tests of the German Me 262 (V-9). Report concludes that a definite amplitude (initial deflection), a certain amount of pivotal friction, and a certain taxiing speed must be produced in order to cause shimmy. Theoretically, this means that the nose wheel should be locked completely to prevent shimmy. The maximum wheel deflection during taxiing is 13 to 15 degrees when the critical shimmy speed (about 31 mph) is reached. It is proposed to install a hydraulic damper on the V-9 model.
-The MK3 was a bad plane , at least bad enough for aerial combat and for it's pilot comfort. Take a look at the 262's cockpit and the meteors Cockpit, just the same as the comparaison between a spitfire's cockpit and the wurger. (i could even use the exemple between the spit and the p51 that also had a nice done cockpit)
A lot of garbage badly placed in the meteor and everything ergonomicaly and logicaly placed in the 262. If you're a pilot and the airforce gives you bird where the workload to fly the plane is nihil (almost) and another where you have to look in crazy ways to check the instruments, because a lot of them is invisible, in what plane will you fly better?
There couldn't be a starker example of the contrast between the design of the Me 262 Schwalbe and that of the Meteor than that which existed in the fuel systems. The Meteor's fuel system was a model of simplicity, and the Schwalbe's system could only be described as 'Byzantine,' to put it kindly. Let's look at the facts:
From Me262Wendell
...The highest permissible rearward point for the centre of gravity is 30 per cent of the mean aerodynamic wing chord. If this position is exceeded, then the aircraft becomes unstable about the lateral axis, that is, it does not remain trimmed, but will automatically stall in a turn. Under normal conditions of fuel stowage this position is not exceeded, but it is necessary to watch most carefully the transfer pumping instructions... Watch particularly that the main tanks do not overflow as the J2 fuel will run out into the fuselage and get on the radio equipment which interferes with radio traffic...[To say the least...]
OK. Let's check the fuel management out -
From ME262PilotDebrief
...There are two main fuel tanks, one forward and one behind the cockpit, each with a capacity of 900 litres... Beneath the seat of the pilot is a reserve tank of 200 litres capacity. Total fuel capacity is therefore close to 2000 litres... The concentration of all tanks near the pilot makes his position extremely vulnerable...Putting it bluntly, the pilot is placed right in the middle of the fuel stowage zone, and the plane itself is more at risk because the fuel is significantly more spread out and hence makes a bigger target than that in the Meteor. In order to get greater range, later versions added a second (600 litre) auxiliary tank at the rear, and reduced the size of the rear main tank to 775 litres – making a grand total of 2500 litres fuel capacity.
From Me262PilotHandbook
Fuel System Controls: ...Fuel transfer is accomplished by operation of the push button switch located in the main switch panel... Fuel is transferred from the main auxiliary tank to the main fuel tanks only. Transfer from the auxiliary fuel tank located beneath the pilot's compartment is accomplished by pumping into the rear auxiliary tank and then into the main fuel tanks. Fuel transfer is automatic upon operation of the fuel transfer switch. Fuel is transferred at unequal rates into the forward fuel tank...Center of Gravity position: ...With the three forward fuel tanks full and the rear one empty, the best center of gravity will be maintained...[Now just keep that in mind]
Fuel System management: Fuel selector switches – the fuel valve controls... have three positions; rear position fuel shut off; center position rear main fuel tank; and forward position front main fuel tank. In order to maintain a suitable center of gravity, the following selector valve positions have been found to be practical –
1. When starting the jet units and taxiing – both fuel selector valves at "rear main fuel tank."
2. During take-off and in flight – left hand unit at "front main fuel tank" and right hand unit at "rear main fuel tank."
After about ten min of flying time, switch on the fuel transfer system. [Turn?] off the transfer system when the fuel gage shows 900 litres... as there may be a danger of the fuel running over.Fuel transfer – fuel transfer switches are located in the right side of the cockpit, main switch panel... Fuel is pumped from the 200 liter tank to the 600 liter tank and then to the front and rear main tanks. The fuel is pumped into the rear main tank at a faster rate than into the front main tank. The ratio is 3:1...
To put it mildly, there are some very real problems here. It's not the sort of complex system you want to be dealing with at any time, let alone in a combat situation. As the well-known Murphy's Law points out, "If something can go wrong, it will ..."
From Design Analysis of Me 262 Jet Fighter
...The fuel system consists of two 238-gal. main tanks plus a 53-gal. reserve and, at least in design plans, an auxiliary tank of about 170 gal. capacity. Both self-sealing main tanks have plywood coverings and are suspended by two straps on the ends of which are bolts that go up through pressed fittings riveted to the inside of the fuselage skin about two-thirds of the way up the side. Nuts are put on the bolts through access holes in the fuselage skin, with the holes covered by doped fabric patches. Each of the main fuel cells has two booster pumps and the reserve tank has one, the system being so arranged that fuel can be pumped from any tank to either engine, or fuel from the rear tank can be pumped to the front. The reserve tank (at least some of these have not been self sealing) goes just in front of the main spar. It istrapped to a single-skin panel, 19-3/4 in. deep by 66¼ in. wide, that is reinforced by six hat-shaped stiffeners and is attached to the fuselage by flat screws placed approximately 1¾ in. apart. Evidence of the Nazis' attempts to get more range out of the Me-262 is shown by plans for installation of the 170-gal. auxiliary tank aft of the rear main cell. It is not known how extensively, if at all, this plan was carried out, for the craft studied was the latest model produced and it had no such installation...Apparently it was installed, as it's mentioned in the Me262 Pilot's Handbook as a 158 gallon tank. As it was located well to the rear, it must have exacerbated the fuel CG problem which Wendell had already flagged up for the three tank system.
The inclusion of non-self-sealing tanks into the mix would just compound the pilot's paranoia with regard to sitting in the middle of the fuel stowage which was already prone to leakage. I don't know the characteristics of the brown coal-based J2 fuel, but I suspect it included some volatile fractions. Cheap and nasty will do just fine when you've got your backs to the wall. The Germans also used aviation gasoline as backup fuel for the Me 262. Looking on the bright side, it would undoubtedly have been a quick death.
On the other hand, the Meteor's system was relatively a model of simplicity. It had one main tank with two compartments, and one ventral drop tank. There were no fuel transfer operations required to be carried out by the pilot during the flight. All the fuel was located right where it needed to be in terms of CG, and gravity acted to distribute it between the two compartments of the main fuel tank.
From the Meteor-CFE Report No 68:
Fuel Capacity:[So no need for a mechanical pump, and the fuel was automatically transferred into the compartments of the main tank as the fuel there was used up. The design was such that there was no risk of overfilling and spillage as there apparently was in the Schwalbe transfer operations.]
15. The fuel capacity is 330 gallons [1485 litres] internally carried in one main fuselage tank which is divided into two compartments; [the] front one feeding the port engine and the rear one the starboard engine.
16. The ventral drop tank of 180 gallons [810 litres] can also be carried, the fuel being transferred to the main tanks by air pressure from the blower on the engine.
17. The two compartments of the main tank can be interconnected by a balance [valve] when the fuel will settle to the same level in the two [compartments]. This does not allow the two engines to be run off one [compartment]......The design range of the centre of gravity is from 27.9% of the standard mean chord to 34.1% standard mean chord. In all cases the centre of gravity lies within this range. The most extreme position reached is for an aircraft with no ventral tank with all its ammunition expended when the centre of gravity is at 33% standard mean chord. The effect of the ventral tank is to move the centre of gravity forward...0.4% when full...
Obviously the other advantage with a ventral drop tank is that when it comes to combat, the pilot can choose to ditch it, hence lightening his craft ready for dog-fighting.
A vast majority of aircraft with a NLG experience nose shimmy and even with shimmy dampners installed weight needs to be kept off the nose during high speeds at take off and landing.
Quote. OK, not necessarily shimmy, but nosewheel nonetheless:
The goal of the Me 262 Project was not to make an identical copy of the original aircraft; some concessions have been inevitable... The Me 262's nose gear was notoriously fragile, with the Germans losing many aircraft to nose wheel collapses. Hammer fashioned a brace for the gear that eliminated the problem.Stormbird | Military Aviation | Air Space Magazine
Regards,
Magnon