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Some numbers you might find interesting.
_____________P-51B____________________P-51D______________________NOTE
15,000 ft_______________________________90°/sec at 210 knots IAS_____ no wing guns, ballast in fuselage for CG limit
10,000 ft_____98°/sec at 260 knots IAS____71°/sec at 200 knots IAS_____ both AC with normal fuel and military load, post-war tests
re P-51D Stick Forces
from a post-war test done by flight test pilots:
__In the course of conducting an analytical comparison of the Mustang, Hellcat, Thunderbolt and Corsair ". . . test pilots measured the [P-51D] Mustang stick force at 70 pounds for a 4G turn and about 90 for a 5G turn at maximum level-flight speed, about 240 kias for their test. Those are estimates, since their force gauge went to only 60 pounds."
__The unanimous view of the test pilots was ". . . the [P-51D] Mustang was a two-handed airplane in which prolonged hard maneuvering was extremely tiring"
from Jeff Ethell, air show pilot with thousands of hours flight in different aircraft and a lot of them in the P-51:
__When flying the P-51A "I could move the stick at high speed without using two hands as I normally would in the D."
Several comments, Thomas - but first an answer. 'Deflection for B-51B-1 as tested - unknown'. ALL P-51B-1 left the factory rigged for 12 degrees.Hey drangondog,
The roll rate chart in the NACA TR No.868 report from 1947 is a gathering of actual measurements of the various aircraft's roll rates. It says that in the report text, plus I found the following RAE(?) chart from late-1943 (you can just barely make out the year in the upper left corner) from which the Spitfire, Fw190, Mustang, and Typhoon roll rates were taken. The Mustang was the Mustang Mk I NA-73 model (aka XP-51/P-51).
The NACA report also shows the P-51B-1-NA roll rate. The curve indicates that the aileron deflection has been increased (presumably to the 15° you mentioned, hence the hump in the curve and the significantly higher roll rate at slower speeds).
Do you know which of the mods you mention above would give that curve?
View attachment 595966
Several comments, Thomas - but first an answer. 'Deflection for B-51B-1 as tested - unknown'. ALL P-51B-1 left the factory rigged for 12 degrees.
Comments, The wind tunnel examinations discussed also highlighted several variables hard to properly quantify, including torsional stiffness of the wing.
That said a.) P-51B-1 was the first +/- 15degree deflection rigging. The P-51B-1 wing and aileron/wing attach were improved from two hinged sealed/balanced aileron to stiffer wing (from earlier P-51A which was stiffer than A-36 and all preceding Mustangs). When both the aileron changed to improved seal/3 position attach hinges (P-51B-5/C and the load carrying ability was upgraded to 1000 per rack (P-51D) the wing was at peak until P-51H.
I'm unclear regarding the XP-51 Roll Rate figures presented - think they were from cusped ailerons. From March 1942 through May 1942, the XP-51 was extensively dive tested and roll tested including examination of wedge vs cusped and roll rates developed for 10, 15, 17 and 20 degrees. NAA was conducting similar tests and concluded the optimal rigging required at least 12 degrees for optimal combination of low speed roll authority combing with improved high speed rates.
I've read the report in the past - but for first time did not notice that the NAA/NACA 45-100 airfoil was Not shown in the tables. I could have overlooked it, but..
Do you have any pictures of the "cusped / wedged" ailerons, or the improved seal/3 position attachment hinges?
Cheers,
Biff
Biff - download the report, it has examples of both the wedge and the cusped ailerons in the front 1/3 of the report. Ditto on balanced/sealed (last 1/3?) but I didn't see reference to 3 hinge P-51B-5 (&Subs) modification.Bill,
Do you have any pictures of the "cusped / wedged" ailerons, or the improved seal/3 position attachment hinges?
Cheers,
Biff
Biff - download the report, it has examples of both the wedge and the cusped ailerons in the front 1/3 of the report. Ditto on balanced/sealed (last 1/3?) but I didn't see reference to 3 hinge P-51B-5 (&Subs) modification.
I'm not sure how to answer your question. The NACA report (By memory) is based on calculations - not flight tests, but I will pull it.Hey drgondog,
The roll rate chart in the NACA TR No.868 report from 1947 is a gathering of actual measurements of the various aircraft's roll rates. It says that in the report text, plus I found the following RAE(?) chart from late-1943 (you can just barely make out the year in the upper left corner) from which the Spitfire, Fw190, Mustang, and Typhoon roll rates were taken. The Mustang was the Mustang Mk I NA-73 model (aka XP-51/P-51).
The NACA report also shows the P-51B-1-NA roll rate. The curve indicates that the aileron deflection has been increased (presumably to the 15° you mentioned, hence the hump in the curve and the significantly higher roll rate at slower speeds).
Do you know which of the mods you mention above would give that curve?
View attachment 595966
All true, but, had there been a P-51 equipped with an equivalent Merlin to the Spit-the Battle of Britain could have ended much sooner with much less damage to England-if any at all. The Mustang had the range to hit any airfield the BF-109s could fly from, with a long loiter time as necessary over occupied France or Belgium. The losses on the ground may well have forced Germany to pull their fighters back too far to have the range to even reach England. Coulda-woulda, since there was no such animal.There are a couple of things to add to Rochie and Bobbysocks post. The Spitfire and especially the Hurricane were game changers in 1940, without them it is possible there would be no place for any P-51s to fly from. The real game changer was US industry producing 4 engine bombers, without the bombers what threat is a P-51 to German industry and infrastructure? In the action described by Bobbysocks of his father, the Spitfire was doing what it did throughout the war, protecting the UK with all its bases which included USAAF bases. In these discussions "time is of the essence". In 1940 the P-51 didn't exist, but even if it did it would not be a better interceptor than a Hurricane or Spitfire with a 1940 Merlin engine. It may have been faster than both when it got off the ground and up to altitude, but it weighed a ton more and with only 1000BHP that is a massive extra weight to haul up to 25,000ft you cannot zoom climb until you have first climbed.
All true, but, had there been a P-51 equipped with an equivalent Merlin to the Spit-the Battle of Britain could have ended much sooner with much less damage to England-if any at all.
All true, but, had there been a P-51 equipped with an equivalent Merlin to the Spit-the Battle of Britain could have ended much sooner with much less damage to England-if any at all.