Pylon and nacelle alignment

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raser13
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Pylon and nacelle alignment

Post by raser13 » Thu Jun 29, 2017 3:26 pm

Hey guys and gals, need help. I'm working on a scratch build of a ship for the local star ship club. And i'm beating my head off the wall ](*,) trying to figure out how to get the pylons and nacelles aligned right with the rest of the ship.

I'm using Enterprise-B nacelles and I have the basic shapes for the pylons I want to make. But I want to make danged sure that I get the pylons symmetrically aligned with one another. And I want to insure That the nacelles are evenly spaced from the center of the ship and straight and true.

Don't want to glue everything together only to notice one is off at an angle. Or one is in a tad further than the other.

Any tricks or ideas on how to do this right?

This clubs been around for 25 years next month. This is the first time that they will have a physical model of their ship. I really want to do it right, so it will be treasured by them for years to come.
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Zubie
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Re: Pylon and nacelle alignment

Post by Zubie » Thu Jun 29, 2017 3:50 pm

I'd say use a template to hold the pieces correctly while they set. It's not unusual in biplane float plane, and other structures (wing dihedral for instance) where the connection points or connection geometries won't necessarily insure proper alignment. You may need to do some careful measurements and planning beforehand to design the actual templates you will use. The actual template can end up being nothing more than a shoebox with the appropriate V notches to hold the parts.
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raser13
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Re: Pylon and nacelle alignment

Post by raser13 » Fri Jun 30, 2017 8:24 am

That's the main question, how do I get the measurements in the first place? Where do I measure from?

My hull is curved. So how do I make sure that it is straight for one and level for second. I can't figure out where to make measurments from to make this happen.

I'll try to get some pics up later so you guys can see more of what I'm doing and what I'm talking about.
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EVApodman
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Re: Pylon and nacelle alignment

Post by EVApodman » Sat Jul 01, 2017 11:41 am

One way to determine if things on a model are aligned and level is to use a surface gauge. This is simply a pointed object held firmly in a vise or other means with a flat level base.

The model is placed on a flat, level surface with the gauge and the pointer is aligned at some reference point on the model. The surface gauge is then moved around the model to determine if the parts are correctly aligned and not sagging.

If the model is too big then you can construct a gauge using a ruler held securely upright and straight with a plastic pointer taped to the point that you are referencing to. Using this move around the model to check various points for alignment.
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Re: Pylon and nacelle alignment

Post by kenlilly106 » Tue Jul 04, 2017 8:41 pm

A picture or sketch of what you're wanting to build will help, here's a few ideas off the top of my head:

1 - If I remember correctly the nacelles are dead flat where the clear parts mount, you can lay them upside down on a flat surface and get them aligned correctly (level, parallel and square) and then build up from there.

2 - or you can build parts in sub assemblies, making sure each one of them is aligned correctly and then combine them later

3 - May have to build a jig if the hull is curved, you can make your own out of sheet styrene or use Lego bricks or a combination thereof. Don't use anything soft like clay.

4 - I have seen models where alignment points are temporarily installed, you can use some very stiff wire, rod or tubing for it, then at the end cut them off or remove them and fill the holes.

Ken

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raser13
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Re: Pylon and nacelle alignment

Post by raser13 » Wed Jul 05, 2017 4:33 pm

This is basically what I'm trying to accomplish with a few embellishments.

Image

But here is where I'm at now.

Image

Image

Image

Image

Any suggestions would be awesome
i love it when a plan comes together
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kenlilly106
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Re: Pylon and nacelle alignment

Post by kenlilly106 » Wed Jul 05, 2017 8:37 pm

Build a jig and use the surface gauge idea from EVApodman.

You've got a nice dimple in the center bottom of your primary hull, you can make a pin with a rounded top to match that dimple and that will support the front of the ship. The notches in the rear of the secondary hull can be used to hold it in place. Those can also be used for your measuring reference.

Draw a centerline on the surface you're using as a reference and that will get you a place to measure from, jsut make sure the ship stays level and aligned properly.

Build a jig to hold the main body level front to back and side to side, then build another support to hold the nacelles, start with one nacelle, get it level and square and then align the other one to match.

It's going to take some back and forth with the measuring and jigs to get everything where you want it to be, I would start with getting the ship level and aligned first, then do one nacelle and once you're happy with it use those measurements to align the second one.

Ken

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raser13
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Re: Pylon and nacelle alignment

Post by raser13 » Thu Jul 06, 2017 4:41 am

Thanks guys, I appreciate all the knowledge. I was lost as to how to do it before. I've got a rough plan going now. I hope it all turns out OK. Got to learn how to do this sometime.
i love it when a plan comes together
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Zubie
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Re: Pylon and nacelle alignment

Post by Zubie » Fri Jul 07, 2017 6:19 pm

I've never used it for this purpose before, but I'm wondering if Moonsand might not be useful for figuring some of this stuff out. My kids had the stuff when little and it came with molds you could either set into it, or press into it and it would hold the shape. I don't know if you could pour plaster or some such to get the basic shape or something, but I wonder if you could sit some cardstock in it carefully and delicately trace out a pattern or getting measurements for making a jig.

Apparently they've changed the brand name to ShapeIt! sand, although I see there are more brands now and even DIY formulas on the net. I suppose you could do the same with a bucket of clay (which bizarrely enough I had for quite some time)
La maquina sobre mi escritorio es una "computadora" del latin "computare", no un "ordenador". El estado de mi escritorio afirma eso. (yo)

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