Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: wooly15 on November 13, 2007, 03:48:27 PM
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This past weekend I was doing some painting at home. While carrying a 5 gallon bucket of paint that was pretty d*** heavy I thought about the weight of paint on a plane. Your average 5 gallons of paint weighs about 60lbs. How many gallons did it take to paint your average plane and how much weight did it add? A spit or a 51 wouldnt take that much paint, but when you get up to the heavies, thats alot of paint. It's probably minimal weight but got me thinking.
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The first shuttle launch
(http://www.aerospaceweb.org/question/spacecraft/shuttle/sts1-liftoff.jpg)
Subsequent looks on the launch pad.
(http://www.aerospaceweb.org/question/investigations/challenger/challenger1.jpg)
NASA thought it was important enough to stop painting the external fuel tank to save weight.
Your 60lbs per 5gal would be quite a bit less after the "solvent" or vehicle component would evaporate off though.
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I think it was more the drag and visibility issues that led the USAAF to stop painting planes over Europe.
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i didnt know that nasa originaly painted the shutles ext tank
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Myth or truth?
VVS used lime wash over standard colour schemes for winter camo (this is true).
As this tended to degrade over time some ground crews used a mix with less water. Lavochkin found that this additional weight and poor surface finish was sufficient to reduce top speed by some 5km/hr on the La5F /FN
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NHRA teams found black and white paint are actually lighter. John Force painted his cars white the next season, others went black some didn't care. I think most have gotten over it and back to the other colors.
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I mix printing ink for a living ( for a food package manufacturing company. We print/make the bags for Frito Lay, Malt-O-Meal, Hostess, etc). While it isn't quite the same as paint, there are some similarities.
One, it doesn't all weigh the same amount when measured by volume. Different pigments are used for different colors, and those weigh varying amounts. Also, different amounts of resins, solvents, etc, are used in different colors. Coverage varies greatly too. A pound of one may "go further" than a pound of another. Mostly due to viscosity and opacity requirements.
For us, white is by far the heaviest color. A 5 gallon pail will hold over 60#, while a 5 gallon pail would overlow with less than 38# of black, or many of our other colors. Our "lightest" color would be our "clear extender", which is ink without any color pigment. 5 gallons of that is only about 34#.
I vaguely remember reading that payload on the shuttle costs its weight in gold to launch. A few hundred pounds of paint = a few hundred pounds of gold?
Paint itself can be costly too. I know some of our 55 gallon barrels of ink cost more than $38,000! That was fancy glow-in-the-dark ink though...
MtnMan
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Yes, the paint weights...in small r/c planes 1oz of extra weight can be critical, on the other hand B747's empty weight increases around 1200lbs when painted...it's the percentage the paint's weight makes of the total weight that matters. :)
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Was looking something else up and happened upon this relevant comment.
Late in 1943 the USAAF decided to discontinue camouflage on bomber and fighter aircraft on the grounds that this paint added weight and drag, apart from being an unecessary burnden on production facilities in both time and cost.
Lightnings were the first 'naked' aircraft types from production to arrive in the UK devoid of camouflage paint. These were in the P-38J-10-LO range, early examples arriving in February 1944
~American Eagles, P-38 Lightning units of the 8th and 9th AF, by Roger Freeman
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Hehe, saving weight by skipping paint sort of sais "boo" to those who think that wingloading is not a big issue :D