Waltz41 Posted March 17, 2017 Share Posted March 17, 2017 I've been searching the internet and books, trying to get a definitive answer on this. Not sure if I'll find it, but thought I would ask here as the forum is usually a lot of help! Searching on the internet just makes me more confused honestly. Straight up question is this: what color for the cockpit floor and the wheel wells on the P-51A/A-36 models? I'm working on the accurate miniatures 1/48th scale kits, the P-51A and A-36. I know the cockpit floor is curved as it's part of the wing spar, and I thought I had read that the wing spar of the Mustangs were painted yellow zinc chromate. Interior green is what I'm using in the cockpit, but was wondering if that floor would be still yellow zinc chromate, based on sub assemblies when they built the mustangs. I have not seen one modeler do this though! As far as wheel wells go, I've seen on various people's models the green zinc chromate used a lot of course, but then I've also seen aluminum or natural grey as well. There's a good color video out there of an A-36 squadron from WWII, and in one shot it definitely looks like the landing gear leg inside is definitely not greenish at all, more aluminum or grey. Then you will also see people do the inside of the gear doors grey or aluminum with the green zinc chromate 'strip' that runs down the middle of the door. Anyone have any good info on this? Thanks in advance. Quote Link to post Share on other sites
Slartibartfast Posted March 17, 2017 Share Posted March 17, 2017 Your gear door is a non-issue. It was very rare that the doors were down when on the ground. They didn't droop like Merlin-powered P-51 doors. Same with the flaps. Down only while undergoing maintenance. The cockpit floor was the top of the wing, not the wing spar. I have to leave shortly, when I return home I'll look through my books for floor color. Quote Link to post Share on other sites
Waltz41 Posted March 17, 2017 Author Share Posted March 17, 2017 Ok, thanks. I didn't know they didn't droop as much as the Merlin powered P-51's. Thanks for that info. Now that I look at more and more actual pics, I can see that! The wells though, green zinc chromate or aluminum insides? I screwed that up, you are right it's on top of the wing. I'm assuming then just like the rest of the cockpit the floor should be interior green. Quote Link to post Share on other sites
DonSS3 Posted March 17, 2017 Share Posted March 17, 2017 IIRC, it should be the same color as the rest of the interior. I think the instructions went something to the effect that all areas visible to the crew should be Interior Green (or in some cases Dull Dark Green). Quote Link to post Share on other sites
tourist Posted March 17, 2017 Share Posted March 17, 2017 The cockpit floor on Allison Mustangs was Interior Green. The wheel bays were a mix of unfinished aluminum parts (the "roof", ribs) and primed ones like the main spar, stringers, brackets etc... (yellow ZC and green ZC on some smaller parts). These finishes could vary. Quote Link to post Share on other sites
John Thompson Posted March 18, 2017 Share Posted March 18, 2017 Very helpful - I've got a couple of Allison Mustangs in progress, and I'm at the stage where I was starting to wonder about wheelwell colours, so thank you, everyone! John Quote Link to post Share on other sites
mawz Posted March 26, 2017 Share Posted March 26, 2017 The inner doors on Allison Mustangs had locks, so they would not droop. The locks were removed on the B model, as the gun camera had been relocated to the wheel well on the A, and the locked inner doors became an access issue. Quote Link to post Share on other sites
timc Posted April 6, 2017 Share Posted April 6, 2017 (edited) On 3/26/2017 at 11:58 AM, mawz said: The inner doors on Allison Mustangs had locks, so they would not droop. The locks were removed on the B model, as the gun camera had been relocated to the wheel well on the A, and the locked inner doors became an access issue. P-51D's reinstated the mechanical locks? Edited April 6, 2017 by timc Quote Link to post Share on other sites
mawz Posted April 6, 2017 Share Posted April 6, 2017 (edited) 44 minutes ago, timc said: P-51D's reinstated the mechanical locks? Those are latches, not locks, they release when the hydraulic system depressurizes after shutdown. The setup through the A was different and featured a releasable positive lock. Edited April 6, 2017 by mawz Quote Link to post Share on other sites
Sowar Posted April 7, 2017 Share Posted April 7, 2017 (edited) 22 hours ago, mawz said: Those are latches, not locks, they release when the hydraulic system depressurizes after shutdown. after the shutdown the hydraulic pressure accumulator maintains around 450/500psi. On the ground, when the a/c was parked, the pilot pull the ldg fairing door emergency release... Edited April 7, 2017 by Sowar Quote Link to post Share on other sites
mawz Posted April 7, 2017 Share Posted April 7, 2017 Interesting, That's at odds to the general explanation I've normally seen for the bleed-down, but makes a lot more sense. I'd guess this also releases pressure to the flap system, allowing bleed-down there too. Quote Link to post Share on other sites
Sowar Posted April 8, 2017 Share Posted April 8, 2017 (edited) As I wrote, the pressure on the hydraulic strut of the flaps (or other) is maintained by the accumulator.* on the ground, the pilot lowers the flaps to facilitate the access and to avoid to step on the flap accidentely. a displacement of the piston of hydraulic strut could be give a asymetrical setting of the flaps. "after landing, flaps UP when taxiing" , this is suppose that the flaps are lowered when aircraft is parked * when the engine run the pressure in accumulator reach 700psi, Engine off, the pressure down to 400/450psi mini. Edited April 8, 2017 by Sowar Quote Link to post Share on other sites
Slartibartfast Posted April 8, 2017 Share Posted April 8, 2017 (edited) That doesn't jibe with the thousands of war-time photos of Merlin-engined Mustangs with inner landing gear doors and flaps in various stages of droop. If the system actually maintains pressure, then something else is going on. When I get home, I'll have to dig out my F-51 Pilot's Manual and see what it has to say. Edited April 8, 2017 by Slartibartfast Quote Link to post Share on other sites
mawz Posted April 8, 2017 Share Posted April 8, 2017 (edited) 4 minutes ago, Slartibartfast said: That doesn't jibe with the thousands of war-time photos of Merlin-engined Mustangs with inner landing gear doors and flaps in various stages of droop. If the system actually maintains pressure, then something else is going on. I do know dropping the flaps was part of the normal shutdown process, for several reasons (facilitating access was not one of them, the Mustang was normally mounted from in front of the wing, by stepping onto the tire then climbing onto the wing). It didn't always happen though. The hydraulic system definitely depressurizes over time when the aircraft is shut down. As you note, there is a large amount of photo documentation of this on the Merlin Mustangs. Edited April 8, 2017 by mawz Quote Link to post Share on other sites
Sowar Posted April 8, 2017 Share Posted April 8, 2017 (edited) after the pilot pull the ldg fairing door, this action release the pressure in this circuit only, their weigth could be open them now. In flight there was the weight of landing gear which push the door, but on the ground it must a short or loong time for they are opened and we don't know if the photos are shot a short or long time after the landing. Quote When I get home, I'll have to dig out my F-51 Pilot's Manual and see what it has to say. Flight Handbook F-51D, T.O. 1F-51D-1, 30-July-1957, page 26 Quote The hydraulic system definitely depressurizes over time when the aircraft is shut down No it's not possible except if there is a leakage on the oil circuit or at the air chamber of accumulator. EDIT: when the flaps reach the position selected, the valves close again. The pressure is not longer applied on the piston of cylinder strut. The position is steady. when the flaps are raised, the pressure could decrease when the engine is shutdown but as all valves are closed the flaps don't move down because the hydraulic fluid cannot return to the accumulator or tank and the oil is incompressible. whithout action of pilot, the flaps don't move down. Edited April 8, 2017 by Sowar Quote Link to post Share on other sites
timc Posted April 8, 2017 Share Posted April 8, 2017 On 4/6/2017 at 6:58 PM, mawz said: Those are latches, not locks, they release when the hydraulic system depressurizes after shutdown. The setup through the A was different and featured a releasable positive lock. Latches, locks???? Tomato, Tomatto... They lock the fairing doors up when the landing gear is retracted and are referred to as fairing door locks in the Illustrated Parts Catalog for the P-51D AN 01-60JE-4, Figure 17, pg 44. (and I suspect the same for the P-51B if I can find a P-51B E & R and IPC). The Allison engined Mustangs door operation appears somewhat different, mechanically and I'm digging into that to confirm (or refute) my suspicions. On at least the P-51D, the fairing doors are mechanically activated through bellcranks, rod and cables [fairing door locks extended (gear up) and retracted (gear down) and hydraulically operated (door opening and closing)]. Below is an excerpt from the P-51D E & R Manual on the fairing doors (AN 01-60JE-2, Section 4, Paragraph 5, page 124). These fairing door locks are retracted when the gear is extended (down) and the only thing holding the fairing doors closed is hydraulic pressure in the hydraulic system (engine not running). If the emergency landing gear release handle is pulled out, all hydraulic pressure in the landing gear hydraulic system is exhausted (AN 01-60JE-2, Section IV, Para 5, page 115). With no pressure in the hydraulic system and the fairing door locks retracted (again, normal with gear extended), gravity takes over and will begin to open the doors, pushing hydraulic fluid from the closed side of the gear door hydraulic actuator back to the reservoir (through the emergency landing gear release valve) and allowing the gear doors to gradually open. There isn't any bypass around seals, pistons or anything else that would indicate a failure of a given part of the landing gear hydraulic system. Friction within the hydraulic fairing door cylinders is what determines how long it takes for the fairing doors to open (sans human intervention opening the doors). Lower friction from looser tolerances/slightly worn seals will allow one door to open faster than one with tighter tolerances/unworn seals. That's why you will see photos of mustangs with gear doors up, down and any position in between. If the emergency landing gear release handle has not been activated, pressure within the hydraulic system will be maintained (again sans human intervention) and the fairing doors will stay up (leaks notwithstanding). All this information is available for reading in the P-51D E&R AN 01-60JE-2 available from any number of sources (free of charge). Flaps will not bleed down if the emergency landing gear handle is pulled as it is not in the flap actuation circuit. The flaps must be selected down for them to drop. Quote Link to post Share on other sites
IAGeezer Posted February 9, 2018 Share Posted February 9, 2018 So... was a non-skid coating applied to the cockpit floor, or was it just the Int Green paint? Quote Link to post Share on other sites
Snowbird3a Posted February 9, 2018 Share Posted February 9, 2018 No non-skid coating, just interior green Quote Link to post Share on other sites
IAGeezer Posted February 10, 2018 Share Posted February 10, 2018 18 hours ago, Snowbird3a said: No non-skid coating, just interior green Thanks! Quote Link to post Share on other sites
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