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And I bet they spend more than that $24K stripping and polishing it. Thats pathetic in my humble opinion

-- John

Yah, that is pretty pathetic.

Paint amounting to 360 pounds is pivotal in the economics of an airline?

Well, I am no Aviation Management major but, it hardly seems worthwhile!

Maybe that is why I am a lowly teacher?

CJ

OK, sorry I am an engineer. Forget about the $$$. What about exposing aluminum to good old mother nature? Ain't that what our planes are made of?

i'm with you bill! i love polished AL, and i do think it looks pretty.

i try to ignore what some of these airlines do for cost savings. most of the time it makes sense, but this is a little off, if not out of the box.

I actually saw that airplane in Vancouver the other morning. It simply looked like Air Canada had picked it up from the desert and didn't have time to apply paint before rushing it into service. Just didn't look right in my opinion. The trouble with bare aluminum on commercial aircraft is that it doesn't take long to lose it's shine, then it just looks bad. American's airplanes look good, but I think (and have been told) they polish them somewhat regularly. Oh well... $$$ speaks.

Well, what about polishing costs? I wonder what the ongoing cost analysis figures look like for that?

If I am not mistaken, those are BIG planes!

BTW, I DO like polished aluminum too. I just don't want to be the one polishing them!

CJ

For the heck of it, I did a little computation on excel and crunched some very crude numbers.

My premise for this computation is that the Air Force says if I carry an extra 10,000 lbs of fuel across the Atlantic, I use 10% of it in extra fuel burn, resulting in only 9,000 lbs of extra gas at my destination. So...

360 lbs of paint * 10% = 36 lbs of extra fuel used during a 8 hour flight
36 lbs / 7 lbs/gal = 5.37 gals
5.37 gal * $2.50/gal = $13.43
$13.43 / 8 hour flight = $1.68 per flight hour cost to carry paint on the jet

$24,000 (to remove paint) / $1.68 = 14,293 flight hours to break even
14,293 hours / 12 hrs/day flying customers = 1,191 days for payback
1,191 days / 365 days/year = 3.26 years

Again, these are very crude computations and full of assumptions. So is it worth it to remove the paint? Don’t know for sure? But I’m sure the airlines have some very precise data.

Another related tid-bit for your book of worthless knowledge--I once read that by switching from metal eating utensils to plastic, it saved the airlines xxx dollars per year in fuel savings.

Also, I believe the reason the Shuttle’s center fuel tank isn’t painted is because of weight. From this web site, http://www.bbc.co.uk/dna/h2g2/A2815526, they claim “NASA used to paint this tank white, to match the rest of the vehicle until someone pointed out that the paint alone added seven tonnes to the craft's weight. It was more economical not to paint it, allowing for more payload instead.”

Isn’t one of Van’s mantras -- “build it light!” ???

Sorry for the long post…

-Jim

This really got my blood going, so i ran a couple of quick figures too, i obtained them within about a 2 minute research session of Google (incidentally, the Google founders (2 guys) just bought themselves a 767 for use as a "private bizjet" is that OTT or what?)

If your a "Hell yeah i'd like the grunty engine option!" kinda guy, like the good Capt. John for example, then the big nuts version of the 767 is for you. It uses 720,300lbs of fuel to carry 245 passengers 3000mi, that breaks down to 2940.9lbs / seat / 3000mi, or 241lbs / mile for the plane, that breaks down even further to be 0.98lbs / seat / mi.

so with those rough figures in mind, the whopping 360lbs (thats right sports fans, count them, 360lbs) that they'll save by stripping the paint will give them approx 1.4mi of added range with the current fuel burn. What would that cost you? about 2 bucks per seat? ($490 for the whole plane)

So lets chew on this bone from another angle... They probably commisioned a consortium of angry housewives to come up with weightloss plans for the plane, lets say 5 people brainstorming. (they would certainly have to have an official sounding title, but the naming of consortiums is the domain of another comitte entirely), so 5 people, getting paid, lets be generous, $50k / year each, ($250k / year) and of course they would have milked this thoroughly ("yeah, it'll take us at least 6 months for this project, and the company is definatly going to have to fly us to the bahamas for a month long confrence...") = anyway, in 6 months they spent $125,000 to save less than 500 pinga von pingas per aircraft per flight.

So, how much would they have spent stripping this paint... 12 guys working 12hour shifts for 4 days should have this thing stripped, then they've got to polish her up, that'll take at least a day or two... these guys arent chumps, so they're asking at least $30 / hr. so ummm, carry the 2, drop the 9... $25920 plus the cost of the paint stripper (lets say $10k per plane) and then they've got to pay the medical costs because Pepe (the lead paint stip guy) slipped and fell off the tailplane during polishing...

So lets wrap this up, a Boeing 767 (the big nuts version) has an MCTOW of 450,000lbs, and they thought they'd save a truck load of money by stripping 360lbs off its weight? (0.08% of MTOW)

all this for a 500 dollar saving? Maybie they should have consulted me first, i'd tell them it was a stupid idea, the meeting would be over in 5 minutes and they could pay me with a cheeseburger. Now THAT would be a money saving measure.

I bet it is nothing more than a publicity stunt that IS working!

CJ

Guys,
As a recently retired Air Canada 767 Captain, I will say a few things here.

First of all, the aircraft in question is an old B767-200. One of the shortass, long in the tooth machines and these Montreal based aircraft are used over the winter months to fly from Vancouver to Maui. The -200's do not have a large center fuel tank which makes the aircraft somewhat range restricted. So keeping that in mind, and with a paintjob required anyway, it makes sense to strip it and polish considering that 400 to 500 lbs of paint removal will improve the performance figures a bit more than you might think.

Oh! BTW, these old -200's have the Pratt & Whitney engines which really suck on this aircraft. (GE's Rule!)

It's easy to pooh pooh the slight weight loss, but it could mean getting the next higher flight level and saving more gas than you think. Or, it could mean carrying a couple of extra pax and doing better than breaking even, which on this highly competitive run is hard to do.

Obviously stripping the aircraft is cheaper than stripping and then re-painting the aircraft so you must also factor that into the savings as well.

So, if you take all those factors into account, it makes more sense.

Cheers, Pete

I'm kind of suprised to hear any RV builder take exception, or even notice Canadairs weight savings plan. I don't mean to be critical, but it's a good opportunity for us to have a helpful reminder (me included). We should be thinking weight ALL THE TIME.

Van's whole premise for the design is light, fast, and strong. I've heard it often from the factory. They really are big on light. Light is good. Weight is bad. Light = speed. Light = performance. Light = farther and faster on less fuel $$$

But I think in some cases they take it too far. Their web site said they didn't even prime the demos! Just a topcoat. I'd never take that chance unless I knew I only had 6 months to fly my plane and it was going to permanent storage after that. But I am not priming the internal parts of my empennage except where required.

How many of us are drilling the optional lightening holes in the VS spar doubler? I am. I'm even motivated to drop the 20 pounds I need to lose.

And if the AvGas price situation doesn't improve, I may even consider a smaller engine. So I'm trying to be a little obsessed about weight during my building process and in my outfitting and equipment plans.

Welcome .... Guest

I think your point is very well made. I like you have been taken to losing a few points because of the RV. I think the issue though that people had with the airlines is that they are trying to save money to help them financially. I think that is a false economy.

Most people that try to save weight on their RV's are doing it not so much to save money but to stretch performance as far as possible. It gives bragging rights ya know

Here's my .02 on the primer weight debate...
I'm priming the interior surfaces of the tail and other control surfaces, since they will be out of sight and not easily accessible - I want to be able to forget about them after construction.
I am all for saving weight - cut the lightening holes in the tail and in the tiedown spacers. However, I have used less than half of the AKZO kit (2 gallons) and primed all interior tail parts, all wing ribs, rear spars, and the interior of the wing control surfaces. A decent amount of this went to overspray and/or was discarded as extra. Assuming ~8lbs/gal (it seems a little heavier than water but I haven't weighed it) I have added less than 8lbs total to the weight of the airplane. Plus, a LOT of the weight in the primer is solvent - which evaporates as it cures. I'm guessing I'll have 6lbs or less in primer when I'm done. Well worth it to me for the protection that AKZO provides.
The fuse will be QB, so Van's is taking care of the weight there

Thomas
-8 ailerons

Just for info. I replaced the wing tips on my 152 a couple of months ago. I took a look down the length of the insides of both the wings with a flash light and found to my surprise that the metal after 26 years is still bright. That was the main reason I changed my mode of priming to applying primer where metal contacts metal only. As in rib flanges and skins. Of course I'll prime under paint for sure which is what this thread is really all about.

I agree about the alclad; however, a friend who is an older A/P told me that "they don't make it like they used to" - he says the alclad these days is not as thick as in days past. In any case, if it is intact and unscratched it should be OK. However, I had small areas of corrosion on the edges of some skins that were in my basement for <2 months (maybe due to the non-alclad cut edge?) so I'm protecting those areas that I won't be able to see easily later. Wing skins - I'm gonna leave them bare.

Oh yeah - sorry for contributing to the thread creep - I'm gonna prime under the painted exterior

Thomas
-8 ailerons

Im with you Jim. Everytime I take a gander down the tail of my '73 172 I am amazed by the "house of mirrors" that I see. For me its just priming where assemblies are formed. Untouched alclad will stay bare for my bird.


-- John

Hey Thomas,

The AKZO rocks big time. Glad you talked me out of using rattle can primer.

Hey Bill and Thomas, if you guys have had good luck with your primer system I would love it if you could start another thread in this forum and review it. Some of us would like to know what other options are.

Thanx.

-- Spike

Pete

Oh! BTW, these old -200's have the Pratt & Whitney engines which really suck on this aircraft. (GE's Rule!)

Yea... -80C rule!!! We here at GE love to here that! Now the question is can my 7 stay out of the way of that inlet???

Some ones had a calculation of actual weight of paint that stays on the skin.

Most primers are 12 lbs per gallon.... and if they are normal aircraft primers they are 45% solids. That is if you evap all of the solvent 45% of the weight will remain. Now when you spray ... if you are real good .... you might get 60% of what comes out of the gun to stick on the target.

soooooo 12 lbs * 45% * 60% = 3.25Lbs per gallon of solids on the target.

Some aircraft paints ... are what they call Hi Solids (EPA friendly) they are 60% solids, so the 45% is replaced with 60% or 4.3 lbs per gallon.

Not every color is the same weight per gallon. White is the heaviest.. most are 14 lbs per gallon, with black being the lightest 9 lbs per gal.

I use 1/2 gallon priming the inside of my wings, and tail feathers... and will use another 1/2 gal in the fuze. Double that for prime and then once more for the color coat, mostly white, and I'll put less than 11Lbs of paint on my 7.

Now 7 lbs of extra weight calculates to .00356748 Kts faster at 8000 ft. and saves me .0013 gph.