Navalwarrior
Staff Sergeant
- 764
- Jun 17, 2018
Resp:
Some affection for the B/Cs may be 'psychological' in that 'metal' was behind their head; feeling naked w a bubble canopy.
How much better was the P-51 B/C over the D model?
- Thread starter grampi
- Start date
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Some affection for the B/Cs may be 'psychological' in that 'metal' was behind their head; feeling naked w a bubble canopy.
Barrett
Senior Airman
Hadn't thought of this in ever so long but ref the B/C: the late Dick Turner (354th) preferred the Malcolm hood to the D bubble because the hood was bulged more. "If I scrunched up real close, I could look under my horizontals."
drgondog
Major
The -6 canopy (Dallas Canopy, bulged in comparison with the -2). My father flew the B/C canopy, the Malcolm Hood and both D canopy versions. He liked the Dallas D best, the Malcolm Hood next, the -2 canopy for the P-51D-5/-10-NA next and birdcage last.
drgondog
Major
And low W/L coupled with high HPavail - best of all. The very first P-51B-1-NA flight test hit 453mph at 29K and 4800fpm max climb rate at 8600 pounds GW. Of Course that would be a combat Mustang returning from Berlin and engaging over Holland.
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In the early days of the Mustang/P-51 was there any discussion of a clear canopy?
jimh
Senior Airman
Having flown both the C and D, I personally like the D better, but only for a couple reasons. Visibility in the D is insanely better, and, although I obviously didn't fly in combat, I'd rather have 6 guns than 4. The cockpit of the B/C is much more comfortable and and slightly reclined and the trims are much easier to manage. Any power change requires re-trimming the airplane. The D model trim controls are under the larger throttle quadrant and are fiddly to work with if you are used to the B/C. They honestly both fly the same, although Betty Jane liked a few extra miles an hour on landing, probably because of the weight of the rear cockpit. Chris Fahey, at Planes of Fame, dispelled the myth that the wing was fattened to accommodate the upright .50s. He stuck a ruler in the gun bay of the A,C,and D...the measurements were identical. The D model canopy can also be opened in flight whereas the B/C is closed for the duration...it can and will blow off the airplane even at idle if it is opened on the ground...and it takes 3-4 people to get it back on. The B/C is also faster in cruise at the same power settings but that could be negligible at combat weight. The Mustangs I've flown are all far below a fully loaded airplane. Hope this helps.
Jim
Jim
drgondog
Major
The Brits requested that all delivered Mustangs have Malcolm Hood installed (June-July 1942). NAA installed one at Inglewood (I couldn't find all the documentation) but deemed it too noisy. I suspect that comment was a precursor for 'we can do better'. The XP-51B project was in full effort at this time and different canopies with aft deck removed were tested and layout drawings completed in July-August 1942. The drawings illustrated an A6M type sliding canopy with framework.
When the three NA-102 airframes were sent to experimental hanger in May 1943, (43-12102) plus two NA-102 complete fuselages, re-designated 42-106539/540, three separate projects were underway; 43-12102 was modified with the soon to be prototype NA-106 Cockpit Enclosure, Sliding (bubble canopy) - which I believe was made by forming Plexiglas over a mold. The same type canopy was installed on P-51D 42-106539 as the engineering was completed in July for the new cockpit enclosure. the last NA-102 fuselage and empennage was delivered to the hanger as the new P-51D wings were also installed in August for P-51D 42-106539, then in December for P-51D-1 42-106540. The original 'draped' canopy was damaged during dive tests in November 1943 and both P-51B and P-51D prototype canopies were replaced with the new production -2 canopy.
NOTE: The P-51D and D-1 were Not drawn from the P-51B-10 line as the serial numbers suggest. Those numbers (and subsequent) were assigned to long run NA-106 as six gun wing/birdcage canopy until the bubble canopy project was well underway. NAA then re-arranged the NA-106 contract (and NA-107 P-51E) into NA-104 P-51B-5 (late), P-51B-10 and P-51B-15; NA-103 for P-51C-5,-10 (first block) and new NA-109 for P-51D-5 and Subs.
The lines drawings for the clear bubble P-51D were completed in April 1943.
I believe without substantiation that the production -2 bubble canopy was installed on 540 - the same as on all P-51D-5-NA.
When the three NA-102 airframes were sent to experimental hanger in May 1943, (43-12102) plus two NA-102 complete fuselages, re-designated 42-106539/540, three separate projects were underway; 43-12102 was modified with the soon to be prototype NA-106 Cockpit Enclosure, Sliding (bubble canopy) - which I believe was made by forming Plexiglas over a mold. The same type canopy was installed on P-51D 42-106539 as the engineering was completed in July for the new cockpit enclosure. the last NA-102 fuselage and empennage was delivered to the hanger as the new P-51D wings were also installed in August for P-51D 42-106539, then in December for P-51D-1 42-106540. The original 'draped' canopy was damaged during dive tests in November 1943 and both P-51B and P-51D prototype canopies were replaced with the new production -2 canopy.
NOTE: The P-51D and D-1 were Not drawn from the P-51B-10 line as the serial numbers suggest. Those numbers (and subsequent) were assigned to long run NA-106 as six gun wing/birdcage canopy until the bubble canopy project was well underway. NAA then re-arranged the NA-106 contract (and NA-107 P-51E) into NA-104 P-51B-5 (late), P-51B-10 and P-51B-15; NA-103 for P-51C-5,-10 (first block) and new NA-109 for P-51D-5 and Subs.
The lines drawings for the clear bubble P-51D were completed in April 1943.
I believe without substantiation that the production -2 bubble canopy was installed on 540 - the same as on all P-51D-5-NA.
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drgondog
Major
Jim - IIRC none of the P-51Ds and Bs currently flying have ailerons rigged for any setting other than 10 degrees +/-. I believe that all combat Merlin Mustangs were rigged for 12 to improve low speed roll and roll authority at high GW. I don't believe 15 degrees was used during normal operations. All Mustangs prior to the P-51B were rigged for +/- 10 degrees.
What is interesting is that current warbird ops comparing B to D power settings - at equal Gross Weight - should favor the D as the parasite drag was very slightly less for the D and for same GW, the Induced Drag should be the same. The only differences in the drag build up were a.) lower cockpit enclosure, and very slightly higher for 6 gun ports rather than 4. For combat ops at normal/same load out, the B is favored due to the weight of the extra two guns and 400 rounds of ammo.
Thanks as always for your contributions.
Navalwarrior
Staff Sergeant
- 764
- Jun 17, 2018
Resp:
RAF 112 Squadron requested and received latticed canopy Mustang Mk IIIs. I believe that their desire to become combat ready (original aircraft worn out/loses) realized the delay to outfit their mounts (new canopy) would have been detrimental to mission readiness. 112 Sq also received an A-36A that they used to aquaint their pilots to the airframe of the scheduled arrival of the Mustang Mk III. Their prior use of Tomahawks and Kittyhawks had latticed canopies.
Also, in reviewing many RAF 112 Mustang photos, several have the dorsal fin fitted to the vertical stabilizer . . . but still retain the lattice canopy.
Just found B/W photos of RAF 260 Mustangs, taken in Italy that have the original latticed canopies.
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jimh
Senior Airman
Jim - IIRC none of the P-51Ds and Bs currently flying have ailerons rigged for any setting other than 10 degrees +/-. I believe that all combat Merlin Mustangs were rigged for 12 to improve low speed roll and roll authority at high GW. I don't believe 15 degrees was used during normal operations. All Mustangs prior to the P-51B were rigged for +/- 10 degrees.
What is interesting is that current warbird ops comparing B to D power settings - at equal Gross Weight - should favor the D as the parasite drag was very slightly less for the D and for same GW, the Induced Drag should be the same. The only differences in the drag build up were a.) lower cockpit enclosure, and very slightly higher for 6 gun ports rather than 4. For combat ops at normal/same load out, the B is favored due to the weight of the extra two guns and 400 rounds of ammo.
Thanks as always for your contributions.
you bet! When Betty was down for annual one year I asked where the ailerons were set and they were at 12. I asked if we could set them up to the 15 mark and the rear cockpit prevented that. In both the D and B/C the ailerons are mushy at slower speeds. It becomes a heavy rudder airplane from base to final on landing. It handles crosswinds beautifully but it would have been nice to have a bit more aileron authority. We flew in just about every wind and weather condition you can imagine. It was never unsafe but it would have been nice to have that extra bit. I've flown 5 Mustangs and I think only Crazy Horse and Lady Jo had a snappier Roll rate. I cannot say where they are rigged. We ran BJ by the book except for takeoff power. We used 55" of manifold pressure instead of 61" per Roush Engines. It would do it and it is spectacular, amazing what that extra 6" does but we were in for long term engine life. Any power settings below that were per the 1944 manual. I've flown formation with D's and noticed a much lower manifold pressure while flying wing versus lead. Again this is all non war time experience but not much has changed other than the guns and ammo.
Jim
What is interesting is that current warbird ops comparing B to D power settings - at equal Gross Weight - should favor the D as the parasite drag was very slightly less for the D and for same GW, the Induced Drag should be the same. The only differences in the drag build up were a.) lower cockpit enclosure, and very slightly higher for 6 gun ports rather than 4. For combat ops at normal/same load out, the B is favored due to the weight of the extra two guns and 400 rounds of ammo.
Thanks as always for your contributions.
you bet! When Betty was down for annual one year I asked where the ailerons were set and they were at 12. I asked if we could set them up to the 15 mark and the rear cockpit prevented that. In both the D and B/C the ailerons are mushy at slower speeds. It becomes a heavy rudder airplane from base to final on landing. It handles crosswinds beautifully but it would have been nice to have a bit more aileron authority. We flew in just about every wind and weather condition you can imagine. It was never unsafe but it would have been nice to have that extra bit. I've flown 5 Mustangs and I think only Crazy Horse and Lady Jo had a snappier Roll rate. I cannot say where they are rigged. We ran BJ by the book except for takeoff power. We used 55" of manifold pressure instead of 61" per Roush Engines. It would do it and it is spectacular, amazing what that extra 6" does but we were in for long term engine life. Any power settings below that were per the 1944 manual. I've flown formation with D's and noticed a much lower manifold pressure while flying wing versus lead. Again this is all non war time experience but not much has changed other than the guns and ammo.
Jim
drgondog
Major
Malcolm couldn't keep up with the demand for either AAF or RAF; Col (later General) Griswold ordered all inbound Mustangs to be equipped with Malcolm in October 1943 - when just three Mustang FG were slated for ops by February, 1944.
The DFF kits began shipment in April 1944 and began installations in June 1944, along with Reverse Rudder Boost Tab to increase rudder/rudder pedal resistance at high speed - particularly dives. The Mustang empennage, while designed to AAF standards, was not adequate to achieve yaw stability could not resist severe torsion and lateral loads caused by combination of rudder input and prop upwash/downwash on Stab and Fin. When the combined loads were imposed, causing yaw, the pilot's natural response was rudder input. At high speeds or severe asymmetric loads such as roll/snap roll, the tail occasionally failed. Your post had nothing to do with the oft repeated myth that cutting down the turtledeck on the D caused instability in yaw - but the problem was noticeable with the Mustang I converted to Merlin in late 1942.
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bobbysocks
Chief Master Sergeant
when did the last B/C roll off of the assembly line? Dad to to the UK in Sept/Oct 44. he was flying in combat by Nov 44. I have his mission list and he was flying Bs and Cs up til he got his own D model...Decemberish 44. that is only months away from the end of the war. if the planes didnt meet the 300 hour service life i would bet they flew them, especially on maximum effort missions of which there seemed to be a lot.
drgondog
Major
The last P-51C-10-NT rolled off in August 1944 timeframe (IIRC). I'll have to check the IARC file when I can. B/C still majority of inventory in September 1944. The D was not a factor in the Battle of Germany before D-Day.
drgondog
Major
great feedback. When I alerted Fahey that all Merlin Mustangs were rigged for +/- 10, 12 and 15 he was surprised - thought all were same as earlier Mustangs at +/-10. Jim - would you ask around to get a sense what most of the warbird community rigging is? I had a long conversation with Gruenhagen - as you know a Mustang that went to Bird Col - that was a Crew Chief and then Maintenance Officer - and he was unclear on the actual use of 12 degrees. I KNOW the 355th FG rigged for 12 but unsure if my father (Bert Marshall) ever rigged for 15 - that would require an approval by the Group Engineering officer. There are many times when I wish he was around to read my new book manuscript.
Bill,
Two questions:
1. The larger the number means the greater the aileron deflection per unit of movement from the stick?
2. Why did the Group Engineering Officer need to give approval for 15? I assume it put some additional stress on the wing...
Cheers,
Biff
Or alternatively, does it mean adjusting the limit stops to allow more travel, which wouldn't require reducing the mechanical advantage of the linkage, but would require extending the range of stick travel in the cockpit? The 10, 12, 15 numbers are degrees of aileron deflection, right?
Cheers,
Wes
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drgondog
Major
IIRC the limit stops are contained in the aileron rigging under the cockpit. Not sure if there is a change in the mechanical stick force other than due to increased loads imposed on the ailerons in greater deflection. Yes to each specific limit stop - +/- 10 degrees, or +/- 12 degrees or +/- 15 degrees for both ailerons.
The first such change occurred on the production P-51B but the XP-51B and the NA-83 AM118 (test bed for A-36, as well as four blade HamStd as well as new aileron). The P-51B-1 had a two hinge aileron, the P-51B/C subsequent had a three hinge aileron with stiffened spar/doubler and not interchangeable with the B-1.
As to Engineering Officer approval, I recall dad mentioning it, but it is possible that that 'authority' may have extended to VIII ASC theatre wide. Gruenhagen was sure that a.) post war USAF never used 15 degree stop and was uncertain about 12, and b.) that 12 degrees was used during WWII - to the latter we firmly disagreed as I had multiple inputs from pilots and CC to the contrary.
From a wrench twister's point of view, adjusting the limit stops, especially if there are factory provided optional settings, is a heck of a lot quicker and easier than changing the mechanical advantage of the linkage. As long as the additional stick travel is not an issue, that's definitely the way to go. If pilots in harm's way are not getting adequate roll response, it's not hard imagining field commands quietly going 15° regardless of factory spec.
When's your publication date?
Cheers,
Wes
Glider
Captain
I know I sometimes state the obvious but this is really obvious, even for me.
The title is How much better was the P-51 B/C over the D model?
The obvious reply is - Overall if the B/C was better than the D model, there wouldn't have been a D model.
Firepower in numbers of guns, also in the better reliability of the guns. Plus significantly increased visibility, vital when most pilots were shot down by the plane they didn't see trump any theoretical minor difference in performance.
The title is How much better was the P-51 B/C over the D model?
The obvious reply is - Overall if the B/C was better than the D model, there wouldn't have been a D model.
Firepower in numbers of guns, also in the better reliability of the guns. Plus significantly increased visibility, vital when most pilots were shot down by the plane they didn't see trump any theoretical minor difference in performance.
Except, when you set out to improve a machine, it's not always clear that your "improved" machine is going to be lacking in some significant way from the original. Often it takes trial by fire to discover these things. A slight deficiency in climb rate, roll rate, or WEP top speed might be less important to a procurement officer/ engineer/production manager than to a nugget pilot up against an experten type in a D9.
Cheers,
Wes
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