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HOn3 Scaling
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 Posted: Mon May 30th, 2011 09:24 pm
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Herb Kephart
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Nn2 Designs-

I am completely puzzled by the first sentence in your last post. 3D cad drafting put an end to modelmaking to "ensure actual fittment" 30 odd years ago in industry--even in situations where parts density and interaction are far more critical than aircraft- consumer electronics for one example.


Herb  :old dude:



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 Posted: Tue May 31st, 2011 04:56 pm
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tebee
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Scale rulers don't work very well when you are putting something into a computer too :bg:

They are good if you are doing physical modelling if have known real-world dimensions or a plan in a scale in which you also have a scale rule.

In other cases it probably quicker and easier to use a calculator but a lot is down to personal preferences and which ever way you feel comfortable working in.



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 Posted: Tue May 31st, 2011 07:02 pm
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Nn3Designs
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Herb

For the most part that is true with base designs on Aircraft. But in the fitment/prototyping stages we still have to build parts taking manufacturing tolerances into account when correcting the "perfect" designs as created in 3D CAD applications like CATIA. Sure you can design in those tolerances while creating the models but then you are only using what should be a standard tolerance and not a fitment tolerance. Being that so many manufacturers make parts to it and interact with each other we have to tighten up design and then pray for the best. Case in point is Interior Ceiling Panels in certain Helicopters used in Military applications. Some of the panels are Formed Aluminum as others are Composite structures. The thermal expansion rates of each materials react differently at temperatures. Now when working with "commercial" based aircraft fitment we can just use the "as designed" fitment and not create prototype models to check fitment. Most of those are not the same construction and use thermoplastics vs. Aluminum / Composite construction. Then there is the other issue of Airframe tolerances.... that opens up even more issues that I dare not address.

:)

Trust me when I say this. I wish things were as simple as creating a model on a computer then moving on to the next project. But we have been working on a certain prototype aircraft for almost 2 years now and still have models being created, prototyped, and fitted in the airframe. For some reason we are still another year away from closing this design.



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 Posted: Tue May 31st, 2011 07:11 pm
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W C Greene
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Good Lord-I am glad that I just build toy trains! As for perfect modeling, I have seen some and it has NO SOUL!

                              Woodie



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 Posted: Wed Jun 1st, 2011 08:23 pm
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Nn3Designs
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I agree with you 100%. Usually when I finish something I either sell it or store it away. So far me and wife have graduated the oldest son. Now there are 4 more left to graduate HS... So hopefully I will be able to start layout #3 in my house. Just funding is non-existent with 4 kids and one psudo-adult. But I am making progress on CAD for my 2-6-6 Breckenridge. Machining will begin soon. Hopefully.



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 Posted: Sat Jun 11th, 2011 05:25 pm
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sledhead
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Nn3Designs wrote: Case in point is Interior Ceiling Panels in certain Helicopters used in Military applications. Some of the panels are Formed Aluminum as others are Composite structures.
Are you talking about the ceiling panels that loose all their hardware and end up zip-tied to the stringers? ;) I'm an old UH-1 and UH-60 crew dog, I can tell you right now that industry engineers would have a heart attack if they saw how we do things out in the field. 




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 Posted: Sat Jun 11th, 2011 08:31 pm
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Nn3Designs
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Sled.... LOL. If only the Engineers at Sikorsky would ever read what we post they would re-look at their designs. We do the fitment design based on intended usage being either a gunship or medivac. The commercial stuff is as rotten as well. I am working on the NEW designs used in the 53K and let me tell you from station 82 to 265 is proving to be a nightmare espeically with only a .030" tolerance of fitment. The way this translates in Model Railroading is this: Whether you are a SCALE fanatic, Proto-modeler, or an Arm-Chair Modeler there is one thing that ties us all together and that is the love of what we do. Me being an Engineer by trade I am more of a SCALE fanatic. I have even caught myself measuring bolt heads and complaining when they are "not to scale", but I have enrolled into a 12 step program for help. LOL...

But in all seriousness, however you model, do what brings you joy and have fun. If the door handle is not 100% perfect so what. The only person that will know is you and from 4 feet away who really cares anyway. Hey look I made it past level 2... WOOT... :D



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 Posted: Sat Jun 11th, 2011 10:02 pm
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sledhead
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Oh I agree. I'm only a harsh critic of my own work, I love seeing what other guys do no matter what their philosophy. You can learn something new from almost anyone.

You wouldn't know who designed the new machined drip pans for the hawk, do you? Those things had the chip detector and filter bowl covers machined so tight a couple damn grains of sand were enough to make them impossible to remove, not good for desert ops, LOL. Plus chip detectors and filter changes usually happen right after a run-up, so of course thermal expansion made them impossible to remove. We pulled out most of the plugs after a week and stored them in the "important parts bin". 



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 Posted: Mon Jun 13th, 2011 12:01 pm
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wclm
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Sled and NN3
   I've found there is only two real critics on your work or designs. The tech who has to repair it or the camera that documents it. The web is full of stuff that is tagged "FAIL".   Don't mean your work personally. Just like when I'm, working on my layout and ask "What idiot designed this" as I struggle to clean a section of hidden track.
                                                            Clif K

Last edited on Mon Jun 13th, 2011 12:05 pm by wclm



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 Posted: Mon Jun 20th, 2011 08:08 pm
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Herb Kephart
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"What idiot designed this"

Don't know how many times I have uttered, nay SCREAMED, a much more colorful version of this when working on newish autos.

But when working on pre WW2 cars, it's usually "dang, they were pretty clever back then"



Herb  :old dude:



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