Warbird Information Exchange

A past thread got me to think this: Let's assume you have an appropriately sized hanger, all the appropriate machines and assembly tools, the right amount of help, no financial issues and every part and piece to completely assemble, paint and test fly a P-51D. Every part has been located, restored and is now ready for assembly. Question: How long under a reasonable assembly schedule would you think it would take to completely assemble, paint and be ready for flight? This would not be an infinite budget scenario like having two hundred assemblers working 24 hours a day. I would assume you could only have so many assemblers so as not to get in each others way. I would assume certain assemblys come before others and I would figure eight hour work days. I'm sure I'm missing several key questions to fill out this theoretical scenario. I would welcome more knowledgable people to embellish to the overall questions. I'm hoping I'm explaining my post clearly and correctly. I would use the recent Meier Motors thread as a possible example. I believe they are assembling a P-51D at this time.

There are many variables here.
Having bodies doesn't mean they are good or adequately trained by today's standards.
Michael Oleary recently published a book all about building the P-51. I suggest you read it and it may surprise you in how it was originally built. Everyone I know of today builds the fuselage as one complete unit. From production break to firewall. In WWII the L and R sides were built in separate pieces as well as several other smaller assemblies and then brought together to be put together as a complete fuselage structure. They even were able to install the fus fuel tank on it's shelf and build the fus around it. It wasn't installed after the fus was built.
That is why dozens of workers could easily build the plane up in hours.

Also today the time to paint each piece to achieve a high quality finish is much different and time consuming compared to mass production techniques.
Today it is all about quality for many of the restorations.

But to day dream this scenario,
A few workers, CNC programers and a machinist could produce tooling to make all the parts and jigs in 9 months to a year. With those parts and trying to achieve a high quality product a fus could take maybe 4-5 days. The tailbone 3 days. A wing maybe 2 weeks. The engine mount maybe 4 days.
Flight controls- ailerons 2 days, elevator the same, rudder a day.
Scoop and doghouse 3 days.
Horizontal -2 days.
The cowling probably a week.
This could probably be achieved after taking 2-3 times this long on the first 10-15 built and scrapping maybe 15% of what you make.
Some of what you envision is being done in ND.

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Rich Palmer

Remember an Injured Youth
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Thx you are very close to what I was trying to ask. Probably right on the money actually as I was interested in the rough amount of time for assembly.

Wow,
I want that shop to put my mustang together ! I can tell you first hand those figures are IF every part is 100% complete.I mean overhaul or new, painted,jigs, a crew of at least 4 on each sub assembly that has done a few before & if this includes exterior paint and armament this will make a world of difference . I can tell you from speeking from experience , currently I am have Mustang 44-73079 assembled and when we started the fusalge was done , the tail cone was 90% , wings 50% , flight controls 75%, engine mount 100%, vertical stab, 75% ,horizontal 75% engine prop. needed overhaul , all hyd, eletrical,and instruments & radios 100% REPLACEMENT, many fairings cowlings, replaced , and exterior paint . It will be at least 7000+ man hours to complete . And that is with no armament . With armament add 3000+ hours . It all depends on the level of detail , quality ,and how authentic you want it. 51Fixer is right there are many varibles to the question. Hope this helps answers your question .
Eddie

My response was given 2-5 people on each assembly, not just the same people, but each group that would be experienced building that component.
New parts awaiting the assembly process, sitting on the shelf, already painted. Each would be the same, per some spec. Skins would be pre cut and minimum adjustment of parts would have to be done.

In other words, a factory situation, similar to WWII, but without MBAs running it.

_________________
Rich Palmer

Remember an Injured Youth
benstear.org
#64- Stay Strong and Keep the Faith

BOOM BOOM, ROUND ROUND, PROPELLER GO

Don't Be A Dilbert!

Welcome to WIX Eddie. We like Fast Red airplanes, & Stearman's too.
Robbie

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Fly Fast Make Noise!

Actually, Rich is probably about 50% low on build and completion time. Making the assumption that you are going to produce a significant quantity of them, you are probably looking more like a year to build all the hard tooling and about 4 months to work out the soft tooling. Figure anywhere from 4 to 6 months to get delivery on all of the peculiar extrusions to the Mustang and the forming they need, along with about the same amount of time for the skins that would need to be formed via stretcher presses and drop hammer/hydro-forming. It's gonna take several man days to build up and install each of the systems required. Figure in the time for all the rigging involved and it adds up. With 4 guys that know what they are doing AND everything they need parts and materials wise is there and available, you could probably expect a production rate from first part to flight, of about two aircraft the first year and thereafter about 4 per year. Until you jump your manning up beyond about 12 people, you won't get much of a rate increase.

Just to give you an idea, the F-16, from first chip in the machine shop to a flying aircraft runs about 24 months, and that is with up to 6 or 700 people working on parts and assemblies. That includes inspection times, cure times on certain chemicals and coatings and both automatic and manual component and systems testing. Even though it's been in production for over 40 years now, the required assembly and test time hasn't changed much since the first of the production in the late 70's. Obviously, the 16 is a much more complicated aircraft, but the times are not going to scale down that much for very low rate production, If you were to put it back into production with the wartime rates, assembly times would go down accordingly, but then Mustangs would be like cheap Chevys and anyone who wanted one would have one.

The main thing is that production quantities are going to drive fabrication methods and that will drive assembly times and requirements, with the significant time reductions coming from tooling and prefabrication processes.

Go through the now, REPUBLIC Sticky on the top of this page. The production photos from GRUMMAN and REPUBLIC will show you just how labor intensive and broken down WW2 assembly work was. Everyone had one or two very simple, minor tasks to do repetatively then the part was passed to the next station where the next small or simple task was done. As the clips were riveted to brackets and assembled onto frames which became ribs and pretty soon, VIOLA! a wing happens- but without dedicated planners nothing happens in an orderly manner and @ the factory door, you'd have a skid tub full of parts that never got installed as the project moved along the line because no ne knew it was supposed to go on the project 'here' not there. Boeing is using the WW2 style moving prodction lines for the 737 (at a rate of 35 a month) and 777 and they learned some really hard lessons about 'JIT' and what happens when the semi full of seats and galleys is stuck in the Mid West in a snowstorm. and not @ the line point where they are to be installed. It's just too bad they didn't give the 787 line planning a lot more thought.

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Don't make me go get my flying monkeys-

What's funny is getting a stack of green cards to install various mods on an test a/c that have been set aside due to test plan and sequencing changes....We got a stack for a bird we were just getting out of structural calibration. Two huge boxes of green cards to be incorporated during all of our return to flight work. Discovered that about 70% of the cards were to install and remove some test gear that was never purchased as the particular tests were cancelled by the customer. It drove the planners batty for about 6 weeks going through the process to cancel all the cards and update all the required documentation.


A pox on idiot planners....they cause me more grief trying to get stuff straightened out for our part of production. The good and informed planners are quite rare and our crew treats them like gold...

JIT, if not incorporated correctly is a fast way to kill a company. Get the stocking levels wrong and not allowing for inflow disruptions and it's a recipe for having your production crews standing around with their thumbs in their ears.....

.....and trade their kids for an 'on top of it' expediter

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Don't make me go get my flying monkeys-

I thought I once saw a youtube video of a time lapse military aircraft assembly. I thought it was an F-16 possibly. Very cool!

Here´s one I found, boy these guys are sure slow .. lol

http://www.youtube.com/watch?v=XaLkuz4i ... re=related

Wait, you said "every part was ready for assembly"? If that's the case then 2 guys could easily do it in a few months.

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Those who possess real knowledge are rare.

Those who can set that knowledge into motion in the physical world are rarer still.

The few who possess real knowledge and can set it into motion of their own hands are the rarest of all.

There is a Boeing video on youtube that builds a 767 in 11 minutes , but we all know what Churchill said about Boeing 'Never in the course of human history have so many been paid so much for so little'

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Don't make me go get my flying monkeys-

This is the theory of relativity all over again.

Are you asking the total manhours to manufacture all components? Are you wanting to include the non-recurring setup and tooling costs? Do you want to include manufacturing lead times for components?

In the early 1980s, I'm not sure that a Mustang had ever had a new spar or new longerons put in during restoration (please correct me if I'm wrong here, but I think the first run of aftermarket replacement longerons were made about 1984). The demand was such that if you needed those parts you had a plane only suitable for static display.

If you had all the subassemblies completely restored and just wanted to bolt it together, do the rigging, plumbing and wiring (no sheet metal work or riveting), my guess is that 6 people could probably do it in 3-4 months (3000-4000 hours). Fuzzy 30 year old memories may be playing trick on me though!