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Old Oct 08, 2012, 09:23 AM
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D_FAST's Avatar
Denver CO
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Build Log
SU-25/39 Frogfoot/Hot Wire| Maiden video added

Figured i would move the blog over to here since the build has begun in earnest.

See my brother got a hold of a dynam a-10 2x64mm.

So 2 x 64mm it is.
Im still going to work on the single plan as well.

I tried my best to keep everything scale. The A10 its supposed to be bigger then the frogfoot,in length and wing span.

But there was no way i could squeeze 2x64mm into something scale in size to dynam's a-10.

Im not sure how the they did it!
I had to tweak both the intake and exhaust areas, as well as fatten/widden the whole engine naccles up just to make this work on a 43in wing span.While the dynams A-10 is @ 36in

Im using EPS with this build, its so much lighter then the home depots pink foam.

Im cut all sections at 1" but im using mixture of 1" ad 2" section cuts, example canopy/wing root/front engine nacelles well be 1" to capture the nice curves, the rest is 2"cuts

to make this work i need other empty airframe weight of around 14oz.

Im thinking of a built up wing on this one, and i want to do the full moving stab, but then there is the angle it sits on.
I've never built a wing in such manner so have no way to know how to cad it.

been plowing threw the forums searching for built up+ wing + construction,my head is spinning.
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Old Oct 08, 2012, 10:27 AM
Firecracker!
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San Francisco & Santa Cruz
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Very nice drawings! I'm in the CAD learning stage, so I was wondering if you would mind sharing your workflow for the fuse. Did you have cross sections, trace them, then skin it somehow? Or draw it some other way? I've been doing a lot of searching as well and haven't been able to find much in the way of details.

Also, you might try sending a PM to the guy that does those fantastic Sketchup built-up airframes -- the Rafale, L-39, etc. Clearly he is an expert on built-up construction.

I bet the SU-25 will be a great flyer!
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Old Oct 08, 2012, 11:25 AM
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Denver CO
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3d model to scale. Using as many ref's as possable.

I then do all my scaling based of fsa rules and so forth.

I then start adding in eletronics, etc.. Create my ducting. Then create my stations/cross cutting the 3d model. Unless the model is uber hi res, you get a lot of facets on the formers, I tend to clean them up before printing and cutting using illiustrator.
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Old Oct 08, 2012, 11:25 AM
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white lake michigan
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Oh boy I see a lot of cutting in someone's future No joke my index finger still ain't right. For some reason its still numb and cold.
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Old Oct 08, 2012, 11:30 AM
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Quote:
Originally Posted by unclecrash View Post
Oh boy I see a lot of cutting in someone's future No joke my index finger still ain't right. For some reason its still numb and cold.
LoL and sanding. Like I mentioned gonna try slamming this one out. As my brother won't wait to long with the a-10 maiden.
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Old Oct 08, 2012, 11:51 AM
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Hi D

that's one nice model, looking forward to see it materializes.
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Old Oct 08, 2012, 12:10 PM
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white lake michigan
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Quote:
Originally Posted by D_FAST View Post
LoL and sanding. Like I mentioned gonna try slamming this one out. As my brother won't wait to long with the a-10 maiden.
LOL gotta love it! brotherly Love!!
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Old Oct 08, 2012, 01:07 PM
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Czech Republic, Hlavní město Praha, Prague
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hi, iťs amazing work in 3D - and very clean too
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Old Oct 08, 2012, 02:18 PM
No Guts No Glory
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Switzerland
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Looking good

Looking good, like the structured aproach to building
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Old Oct 08, 2012, 03:11 PM
Firecracker!
BillO's Avatar
San Francisco & Santa Cruz
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Quote:
Originally Posted by D_FAST View Post
3d model to scale. Using as many ref's as possable.

I then do all my scaling based of fsa rules and so forth.

I then start adding in eletronics, etc.. Create my ducting. Then create my stations/cross cutting the 3d model. Unless the model is uber hi res, you get a lot of facets on the formers, I tend to clean them up before printing and cutting using illiustrator.
Thanks, but it's really just the first part I'm asking about: "3d model to scale. Using as many ref's as possible." Can you expand on the steps you go through to create the 3d model for the fuse?

Thanks again!

Bill
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Old Oct 08, 2012, 03:17 PM
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subscribed.
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Old Oct 08, 2012, 03:24 PM
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Super project!!! W
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Old Oct 08, 2012, 06:41 PM
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Thanks for the words of encouragement there fella's

@Billo

Yes, I use and tend to use more then one set of drawings and any cross sections that come with the drawings as guides just like the top and side views.


With Sketchup some required plugins are a must.
Unfold or Flattery
Unfolds your 3d geometery
Sub divide and Smooth
For hi res modeling or organic really not for the beginner but once you grasp quad modeling its awesome tool to have.
Fredo's tool set
Just get them all, to many to list. His curve tools and loft tools are a must for duct work!!

As for modeling technique, Sometimes I push and pull vertices, creating my own faces, box modeling, or creating splines and skinning or lofting.

Box modeling or Polygonal is the way to learn. This is where you start with a primitive shape,then extrude,bevel,scale, and push and pull your way to a rough shape. Then you start by adding in the detail, sub divided to get more detail and so on.


Always check you views, always check and lock your axis when moving vertices.
I really wish SketchUp would have windows or multiple viewports. Save,Save,Save your work,use different names ,you never know when you might have to revert to an older model.

On really complex curves i tend to use the loft and skin plugins, sorta of like a nurb modeler. this entails drawing splines or shapes, contour curves then skinning or lofting between them

Bill I could write a book here. There is so many ways to tackle the same thing if you know what i mean. There is tons of stuff out there on the internet.check around for box modeling, or polygonal modeling, its the basics.

If you have any questions, get really stuck, just PM me i will be glad to help you out.

Did i mention to Save your work?
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Old Oct 08, 2012, 06:53 PM
EDF rules... :)
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Joined Nov 1999
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Thanks for that post, I just started working in sketchup.
I have an extensive background in Inventor but find this program a little difficult to work in.
BTW your modeling looks great.

Eric B.
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Old Oct 08, 2012, 10:13 PM
Firecracker!
BillO's Avatar
San Francisco & Santa Cruz
Joined Oct 2004
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Thanks D, you have helped to crystalize thoughts that have been developing in my mind the last few weeks. I have read enough and modeled enough now that it makes sense to me that you use different techniques depending on the situation.

First off, it helps to know how you want to build something before deciding on a modeling approach and how much detail is needed. I've been using Curviloft by Fredo and thought that was going to do everything, but now I see the value in learning how to hand-draw too.

Eventually I would like to be able to mill a fuse mold directly from a Sketchup model, but I can see a long learning curve before I get there. Thanks for your offer of future guidance, I will surely take you up on that!

Keep those build updates coming!
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