Could it be that the glare you see when the sun shines on it makes it so bright, its harder to see the silhouette. You know that something is up there, but you dont know what, or how high. i can also see now why the brits didnt like it haha

Weight savings is kind of obvious. But I was thinking about less obvious reasons. What I see in the pictures is a lot of planes of unpainted aluminum that are shiny silver in color. Then I also see planes of bare aluminum that are not so shiny. I was wondering if those surfaces were left unpolished to build up an oxide layer to make the planes less susceptible to sabotage from enemy commandos using mercury paste. Also I was wondering if those surfaces were purposefully anodized for the same purpose.

I once read that painting a B747 added five tons to the aircraft's overall weight.

Some airplanes were in fact painted silver in some places. The P-51 wing, for example, was filled and painted back to about the 40% chord point, because they wanted to smooth it out in an attempt to maintain laminar flow.

@@user-ir8lw6vq3onot quite that much, but it definitely adds a LOT of weight to the aircraft

why would they just not use the same glue as the British built ones...?

@@Mmjk_12 It wasn't available. De Havilland Australia had only built Tiger Moths until then. The Mosquito was an order of magnitude more complex. They had the blueprints from Britain, they had the Merlin engines, but everything else had to be sourced locally. The British glue was based on an organic glue that was (I believe, not sure) based on a substrate that was susceptible to attack from insects, which if you know anything about Australia would flash all number of red flags. So they needed a substitute glue but unfortunately that was more susceptible to heat. Swings and roundabouts. All up it delayed the introduction of the Mosquito into RAAF service by at least six months. Good thing they were ALSO license building the Beaufighter,which in its own way was a beast of a warplane .

@@johnreynolds7996 Jesus wasn't expecting that detailed of an answer lmao, thanks for the information it was very interesting :)

Interesting -- the paint must have made a very reflective surface, as generally for heat reduction purposes in surfaces exposed to the Sun, white paint is more reflective than "silver" vehicle paint, unless the silver paint gives a mirror finish almost like chrome plating. Without it, the "silver" is darker overall than white, and thus absorbs more heat.

@@joemcgulligut7874 But white paint makes an airplane stand out more than silver paint, which might have been part of the calculus. In the early cold war US Air Force jets were mostly unpainted. In some locations the sophisticated F-105 spent a lot of time sitting out on the ramp under crappy weather. They started to have issues with surface corrosion as well as moisture seeping into the interior and messing with the electronics. The solution was to actually paint the airplanes to seal the surfaces. Since camouflage was not in use at the time, they painted them with a silver paint that looked a lot like unpolished natural metal. If they painted them white, they would not have looked like combat aircraft.

Spot on! B17 vs B29 was a great example. B29 riveting process meant it was faster without paint. B17 was the opposite.

Da red wunz go fasta!

Now, I have not done any math to test this out. But the larger the plane, the less proportionally the paint should be. Since the coat of paint is about as thick on a larger plane as a small one. So that could be a small factor too. I am sure one could also compare the proportional surface area vs internal volume to of these planes.

Additional tests of unpainted aircraft confirmed increased performance results. The decision to stop factory painting unless otherwise advised on an individual basis was initiated in October 1943. By January 1944 all planes coming off the production line were not painted. Instead, they received a wax coating or were over-sprayed with a lightweight clear coat. Not only were these unpainted aircraft faster; they were also lighter. This meant increased range for fighters and bombers and extra bomb capacity for the latter. No record exists about how much a gallon of paint used on the aircraft weighed. Contemporary reports stated that with the elimination of the paint, fighters would be “fifteen to twenty pounds lighter” and heavy bombers would “lose seventy to eighty pounds.” One recent study on the subject noted that the paint during this period was undoubtedly lead-based and “probably copper fortified.” A gallon of such paint could weigh as much as 30 pounds, though for aircraft it was more likely to be in the 10-pound range. A B-17 has a surface area of 4,200 square feet and took about 35 gallons of paint to coat. If the paint weighed 10 pounds a gallon wet, after accounting for evaporation the weight would be roughly 300 pounds. Given that figure, eliminating the paint would indeed be a major weight reduction.

Paint made the old style rivets a bit more streamlined. Better rivets were later designed to cut drag.

My understanding is that the silver color comes from polished aluminum, which was the primary material for the skin, I think. Not too much corrosion hazard, in that case? Maybe the rivets?

@@mmm-mmm and MB not even having the best stats, it just have pretty good marketing/propaganda value and was popularized.

I've heard that, at peak production, they were turning out B24s about one an hour.

Mill and watermarks on aluminium sheet were deliberately retained. If you read the North American process manual for the P-51 it specifically says don’t remove them.

The ‘silver’ P-51’s in this video do actually have painted silver wings (fuselage was un-painted apart from anti-glare panel). They received bondo filler and primer applications to assist the laminar flow performance of the wing and finished with silver paint.

I had heard this, too. THe weight savings were canceled out because of the loss in aerodynamic drag. Thanks for your correction to this video.

Ages ago I heard that they were faster without the paint.

Spot on comment, you are correct!

Don’t underestimate the effect of finish. I read the memoirs of a German nightfighter, who wrote it seemed unnecessary for him to change away from the BF110 to a more potent plane like the HE219, as he had his plane waxed, panel lines fillered and glossy finish, which made his plane, even with the antler-like antennae, 40 km/h faster. The same thing I heard from my WW I fighter ace grandpa, who said after 3 victories or so your chances of survival rose, as you got better planes and more important, aircraft mechanics.

​@@carlwear1249 No, this video is wrong, painting an aircraft as large as a B17 only added 75 lbs to it, not the "hundreds of pounds" claimed in this video and by so many other sources, the mere addition of 75 lbs was more than offset in the reduction of drag from the paint smoothing over the lap joints and rivets on the exterior of the aircraft, a painted B17 picked up 4 knots of speed and about 200 miles of range from the reduction in drag. In 1944 the US military had the aircraft manufacturer's stop painting aircraft at the factories because it was too time consuming and caused choke points in production and delays in the delivery of aircraft, after that whether or not they were painted was left up to the individual theater commander's. Corrosion resistance also has nothing to do with it, well before WW2 a special aluminum sheet called Alclad which does not corrode was developed for aircraft and other things that need to be made of aluminum and have corrosion proof properties. Pure aluminum does not corrode but it's about as strong as clay, when alloys like copper and tin are added to it to give it strength it also makes it susceptible to corrosion, Alclad is an aluminum alloy sheet that has a pure aluminum coating on it, it's strong like regular alloy aluminum but is also corrosion proof, painting military aircraft never had anything to do with keeping them from corroding, it was strictly for camouflaging.

This is true, you beat me to it. It is the reason why the fuselage of P-51 could be a patchwork of different shades of "silver" depending on the state of the bare aluminum panels, whereas the wings were usually a uniform silver color.

Absolutely correct. Apologies for my post restating this info.

The wings of otherwise unpainted F-104s were also painted to maintain smooth airflow. The upper surface was painted gloss white and the lower surface a standard USAF gray color.

I recall my Grandfather talking about something similair. I was very young but remember him talking about his P-51 air crew buffing his plane with some kind of wax. He spoke about getting more fuel efficiency.

lol

Jimmy Stewart (the actor) flew them in WWII As well as bomber missions over Germany

Ah, you mean pathfinders!

@@bartoszp.7798 No, a pathfinder ship has an entirely different mission task. Pathfinders marked targets.

b 17 bombers were the old exposed Rivet design and it was found that teh Paint on a B17 helped the air flow. the later unpainted Aircraft lost cruse speed at the same Throttle settings. later Aircraft like the B29 and fighters with flush mounted rivets were faster without paint.

How tall was he?

@@badlt5897 5’ 4” at most. But a very well respected orchid breeder. Their B-17 came from the Wichita plant as he remembered the tail number and found it through a printed resource. He thought it was a very late F model, but the record had it as an early G. Could be the ship’s plate had an error with F already fixed on it.

@@michaeltelson9798 I figured. Most ball turret guys were pretty short or they wouldn't fit. Great story.

The more of these built, the better since the targets could be spread among more planes. The process to produce them was helpful along weight, but also along production. The mistake made in the case of these types of planes, they didn't send along paint and gear to finish the job by the crew on the ground maintaining it.

@Brownbear77777 I’d bet my next pension checks that you never had a silver P-51 Mustang. I bet it was made of aluminum. Silver is way too expensive and heavy.

The Navy kept painting their aircraft since the paint help protect the metal from corrosive salt spray at sea.

​@@toqtoq3361rust is a specific corrosion product. Specifically it is hydrated iron III oxide. No metals other than iron and steel can produce rust. Only the ignorant claim other metals rust, they corrode.

​@@neiloflongbeck5705in common parlance 'rust' and 'corrosion' are considered interchangeable terms. Beeeecause rust IS a form of corrosion. Stop being a dick.

Rust is corrosion. Aluminum turns white when it oxidizes, aka corrodes. Why people call it corrosion, no matter what material it is on.

@@johnh2410I was in a patrol squadron 50 years ago and there was a shop that did only corrosion control. Salt air raises hell with planes.

WWII US Bombers did a video that mentioned the amount of distance an unpainted B-17 got over one that was painted. Hundreds of miles and that made a big difference in the Pacific theatre.

Not to mention that the contrails/vapor trails they left in the sky made any camo paint jobs pretty much useless anyway.

Weight-savings was indeed a factor. But when you need to churn out a lot of equipment, time-savings is also a major incentive. Both were clearly important enough to outweigh the maintenance concerns of bare metal. And if you think about it, the US Navy never implemented this. I never saw any US Navy aircraft that was bare metal during WW2.

@@urbypilot2136 Navy & USMC needed the corrosion resistance that a coat of paint gave.

@@glenmcinnes4824 Exactly my point why they never did the bare metal thing.

That has to have been the same story I've read! Only differences I remember was that he made the comment to his crew chief after it had snowed. Some pilots thought the bare aluminum offered better camouflage over the snow than the olive drab. He mentioned it might be time to go to the winter scheme. Then, the reason their hands were so red was because they used the only paint stripper they had readily available and that was aviation gasoline! Always loved that story

Weight was really the big one. If the plane did not need the paint for protection from seawater it was a huge removal of well over 100 pounds of paint. Skipping the full paint also shaved about 2 days off each planes production. And while skipping the paint reduced costs. It's not really in the ways you would think. It was more it reduced the massive logistics chains needed to get the paint to the plane factories. And it eliminated a point of production bottleneck. The paint was still being made and used. Ground vehicles needed painting. But by cutting the planes out of the paint loop created efficiencies throughout war production.

Interesting point! The internet tells me that dry paint is 60% the weight of wet paint so 8lbs would be 4.8lbs. lol, you made me learn something today, thank you.

Paint pigments are more dense than water. Water weighs 8.3 pounds per gallon. Water has a density of 1 so even though it is denser than the organic liquids used to comprise the paint, the pigments would still be heaviest part of the paint. Certain pigment colors used a lot of heavy metals which made them much more dense; easily 4 or 5 times as much. I think the 8 pounds per gallon applied weight is probably conservative.

​@@mmm-mmmBill Lear famously said he'd sell his grandmother to save a pound.

No record exists about how much a gallon of paint used on the aircraft weighed. Contemporary reports stated that with the elimination of the paint, fighters would be “fifteen to twenty pounds lighter” and heavy bombers would “lose seventy to eighty pounds.” One recent study on the subject noted that the paint during this period was undoubtedly lead-based and “probably copper fortified.” A gallon of such paint could weigh as much as 30 pounds, though for aircraft it was more likely to be in the 10-pound range. A B-17 has a surface area of 4,200 square feet and took about 35 gallons of paint to coat. If the paint weighed 10 pounds a gallon wet, after accounting for evaporation the weight would be roughly 300 pounds. Given that figure, eliminating the paint would indeed be a major weight reduction.

That might go for riveted aircraft, especially big ones like the B-17, but I'm fairly sure fighters like the P-51 were welded because that's more aerodynamic. So there paint would make quite a bit of difference.

There’s another KZfaq video that shows the US Army’s very detailed studies on cost benefit of painted vs non. Pretty good video kzfaq.info/get/bejne/aphgmbKQktuUnnk.htmlsi=u3lOR9Eh1JHYxdp7

So this guys conclusion is…incorrect

Never heard of that. 5 Grand, the 5000th B-17 Built was bare metal, but, factory workers where allowed to paint their names all over the plane and it was pretty well covered in signatures. It proved to be slower than the other bare metal bombers. So how does paint help? It would if the plane had been smoothed and the paint highly polished, like race planes, but, these where mass produced aircraft that used flat paints for camo.

@@mypl510 Australia had a wing (three squadrons) of Supermarine Spitfires fighting the Japanese over the Northern Territory and New Guinea. The Wing Commander (Clive Caldwell) was always on the lookout for any edge he could get, so as a test he ordered his own aircraft to be stripped of paint and the bare metal waxed and polished. The end result was that his aircraft was up to 20-25mph faster than any of the other Spitfires - which was A Good Thing - but it also meant that his Spitfire stood out like dogs-balls when he was leading his wing against Japanese Zeros, which from his PoV was not good. Not good at all. So it was a short-lived experiment. But it showed that if you (a) stripped the paint off and (b) then waxed and polished the bare metal then (c) you got a significant increase in speed.

@@mypl510 See World War II Bombers or Greg's Autos and Airplanes for information on speed and fuel burn. The difference wasn't much but it was there. And when 5 Grand got to a squadron the names probably came off. Just like I doubt Yipee the red P-38 stayed red.

That's pretty much what I was told growing up. For the last year or so of the war: 1. Allies had Air superiority, 2. Streamline production, 3. Save the taxpayers some money.

The same for me.

This is true. The paint filled all of the little nooks and crannies in the uneven surfaces of the aircraft. The paint also "raised up" the surface of the aircraft so the rivets didn't protrude as much.

Thanks for that,@@OneHitWonder383

they came out with the ME-262, the first jet acft. but it had a short airtime. make a few passes then back to the barn.

There is a bitter truth to this. A significant aspect of the SBI was that it drew German resources away from other areas. The Allies we’re picking a fight for the fight’s sake, damage on the ground aside.

I always wondered if it was for dog fighting purpose. aluminium would reflect light and throw off an enemys aim.

The B-24 or your great-uncle?

I'm a private pilot, and once I was sharing the pattern around an airport with a natural metal DC-3. At certain angles, the skin reflected the green of the ground vegetation, making it difficult to keep track of its position.

No you didn't, and that had absolutely nothing to do whether they were painted or not. The reality is and what the creator of this video obviously didn't know is that in late 43 they quit painting aircraft at the factories because it was too time consuming and caused choke points in production and delayed delivery of the planes, theater commander's were screaming for aircraft and they told the high command they didn't care whether or not they were painted as long as they had wings and could fly was all they cared about, so from that point on whether or not they got painted was entirely up to the theater commander's and was to be done by the units that got them if they wanted them to be painted, they never had any problems seeing them from the contrails they left behind and you can't hide hundreds of 4 engine bombers or their escorts, the Germans had radar and knew exactly where they were at, the camo paint on the top was because originally they thought that US air bases in England might get bombed which is something that as it turned out never happened anyway, the flat gray on the bottom was because they thought originally that it'd make it difficult to see by AA crews but as that turned out German AA guns had radar along with the fact that with hundreds of contrails in the sky everyone from Sweden to Switzerland could see a formation of 300 B17's and their escorts, many units never bothered to paint them after receiving them when the started showing up unpainted and some simply did it become some military commander's being the way they are wanted every aircraft in their unit looking the same. Ground crews had plenty to do in between missions like repairs and replacing engine's along with preping aircraft for the next mission, as it was they worked around the clock keeping them flying and had no time to strip the paint off of hundreds of aircraft. Quit making things up.

The Navy in the Pacific operated at much lower altitude than the planes in Europe. Most combat took place around 12000 to15000 ft. Europe was 20-30. Hence the blue paint.

@@karlhumes6110 Combat has literally nothing to do with it. Once you're in combat, no amount of cam is going to hide you as you're way too close. The point is you want to hide from interceptors at high altitude while you're closer to the ground/ocean than they are and on your way to a surface target. Fighters require less cam for this reason but still don't want to be spotted from above if possible. A silver Mustang would've stood out on a sunny day like a search light while it was down on the deck strafing ground targets, but they weren't worried about it by that stage of the war.

Glad you enjoyed it

Those tests were done well before the Mk V, on the pre-PRU photo-recce Spitfires back in '39 - these had their panel lines chalked flush , and paint polished for speed

Thank you very much DD I really appreciate the support!

It depends on the altitude. British Photo Recon aircraft were painted all over with a pale blue color called (unsurprisingly) "PR Blue". If was very effective at hiding the aircraft from heavy AA gunfire, but these aircraft operated at high altitude. Their low-level PR aircraft were often painted a salmon-pink color (which had no name) as this helped them blend in with the reddish glow and haze that would occur as the sun was setting. In neither case would bare metal be effective as camouflage because of the risk of sunlight reflecting off the shiny metal. Some British PR aircraft DID use bare metal, but that was for performance reasons (an extra 10mph might make all the difference if an FW-190 was trying to catch you), not for concealment purposes, and once the PR Spitfires got the Griffin engine and the performance boost it offered then they went back to PR Blue.

@@johnreynolds7996 It makes sense. To me it always appeared as though the bare metal surface was less visible unless in direct sunlight, but that was probably just an illusion.