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SEPECAT Jaguar GR3A


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Hi Timmy, Been following this with great interest over the last few months on Britmodeller, fantastic modelling skills! Just had a look at your Youtube film (nicely done and very informative!) and have a query about the Acrylic used for the canopy. Where do you get this from? Is there a brand name for it (bearing in mind I'm in the UK!)

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Hi Timmy, Been following this with great interest over the last few months on Britmodeller, fantastic modelling skills! Just had a look at your Youtube film (nicely done and very informative!) and have a query about the Acrylic used for the canopy. Where do you get this from? Is there a brand name for it (bearing in mind I'm in the UK!)

The sheet I use is cell cast acrylic sheet 0.030" thick. Plexiglass is the brand name though the sheet is unmarked. I got mine from an online plastic supplier that unfortunately doesn't exist anymore, but a little web searching and you should be able to find it. Here's one supplier http://plastics.tridentplastics.com/item/acrylic/grade-preshrunk-cell-cast-acrylic-sheet-mil-p-5425/item-2390?&bc=100|1004|1149|1022|1026. Keep in mind this is premium specialty material not to be found in the hobby store. Look for a plastic supplier, you might find a storefront where you live or an online UK supplier.

I hope that helps you gets started.

Timmy!

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  • 4 weeks later...

Small update finally. Lots of work going on, just not much to show. I am going to change the way I'll be fabricating the final model from the pattern. Don't think many of you will have seen this...but more on that later. As a result I am finishing up all the detail on the forward portion of the fuselage. I'll be making molds and testing the new plan.

I needed some small details that I couldn't get just right by hand. So a little home brew photo-etch session was in order. I used the kit from Micro Mark. Not perfect results but passable. (Pig...your AT-38B panel is in there - it's on the way to you).

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Also part two of the Canopy Video is up...enjoy.

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Thanks as always for the support and platitudes!

Heavy construction of the canopy is now complete. Photos and video shall speak on my behalf.

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Moving Picture

Edited by Timmy!
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  • 4 weeks later...

Quick update,

Lots of little detail work on going.

Final fitting of emergency canopy open handle.

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Cockpit sill work is done.

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By popular demand another video is in the works.

That's it for now,

Timmy!

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  • 3 months later...
  • 3 months later...

Yikes has it really been since April that I posted last? Well all I can say is I've had a lot to do over the last months. A list serving as a shameless excuse for my lack of model progress follows:

Care and feeding of GF.

Trained for and ran a 1/2 marathon (under 2 hours).

Partied with Pig.

Begged for forgiveness from GF.

Trained for and rode a Century (5 and a half hours - 18mph average)

Took GF to Palm Springs (that's where the Century was - two birds and what not)

Evacuated a portion of the Gulf of Mexico to escape a tropical storm.

Recurrent training in S-92.

Took GF to Stillwater, Minnesota for 10 days of summer fun and meet the extended family.

Turned 42.

Went to DC to see a buddy.

Bought nice dinner and flowers for GF, she wasn't invited to DC.

I think that's it - too many months went by for me to remember everything.

Meanwhile I have been working in the background on the Jag. I have made molds of the project so far (several actually) and have been working on a process to make a metal casting of the model. Originally my plan was to use various epoxies to cast copies of the Jag. However, I really want an archival model - so with the possibility of sag, deterioration, UV issues with clear parts I looked for an alternative. A few months back I found one and have been experimenting with the process. About three weeks ago, I did manage to create a successful part in metal, that was about 0.015 thick shell with perfect fidelity of the surface detail. ***PICS TO FOLLOW*** Unfortunately, now having a finished part to play with I found a few problems, that are derailing my enthusiasm to use this method. It's turning out to be significantly more expensive than I anticipated with high failure rate of finished parts. Post processing of the parts it turning out to be more difficult than expected as well. The mantra of "what do I do?...what do I do?...what do I do?" set in my brain for the last few weeks.

The scariest thought I could ever imagine bubbled to the top of my brain housing group. Start over. First, the modeling process had done some minor damage to the master, that needs to be repaired. The first metal process was so good that I was capturing fingerprints - but all the construction flaws too. I have all this CAD work that would go unused, for example, working landing gear in the CAD-o-verse that would not make it on the model in it's current iteration.

So with the pro and cons weighed, my ultimate answer is "Yes, let's start over - what the hell!" WIth a new list of goals in hand: Nearly all metal construction, rubber and acrylic bits where necessary (per the real thing), working stuff (gear, flaps, and remove stores etc.), better surface detail and symmetry, modular construction (family model in mind) and one more change to catch all the shape and detail I may have missed.

How am I going to do this you say? Robots!!!

My project from last week:

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It's a Sherline Mill with a CNC conversion I installed and set up. I'm still working on the CAM software solution - but that is just a matter playing with trial copies of the two systems chosen and ordering the winner. I really really hope to be cutting metal the week after Thanksgiving.

Since, as you may have guessed I'll be cutting parts directly from the CAD model - the model itself is in need of modification. I'm essentially redrawing the model, enough not from scotch. The process starts by breaking up the model into parts small enough to fit in the mill. While I'm at it, I'm fixing all the shape issues that weren't necessary to be concerned about for the hand built CAD model. The parts are broken along panel lines on the prototype which should result in "natural" panel lines on the finished model. Also you'll notice recesses for access panels, that will be filled with sheet aluminum panels, just like the previous model. Other surface details will be engraved/embossed after the mill has cut the parts. I'm anticipating some hand work after the parts are cut to reproduce wrinkles and fine shape fixes etc. Here is some of that work.

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So here's the plan as I see it now. Since I have computer time while I'm away at work, I can model there and produce parts while home. We'll see how it goes.

That's it for now…

Timmy!

p.s.

Thanks for hanging in there this project it will get done - eventually.

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  • 2 weeks later...

Ok so as promised aluminum has been cut. Baby steps though. Actually much work has been done getting the mill properly aligned and set up. So with out further audieu:

I MADE A RECK TANGLE! (In mind of 3 year old talk)

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Way harder than you might think - lots of machine adjustments and a day and half of work. But at least I can now make the stock needed to cut parts from.

More soon, playing with CAM software, getting G-code done and more fiddling with the mill. Hope to be starting first CNC cuts in anger tomorrow.

Timmy!

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Welcome to modeling class ARC 101 boys....I'm ready to sign up..where's the sheet. This is going to be off da charts :thumbsup::worship:

You are a MADMAN!!!!!

You know there's a very fine line between sheer madness and pure unadulterated Genius...and I don't see a mad man here.....well as of yet that is.

Edited by #1 Greywolf
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So this is turning out to be 3d printing just a subtractive process. Another analogy is this is the Windows method of 3d printing vice the Mac way. In other words, it hard to get it right with all the variables that have to be manually set. I'm not saying is not a lot of fun, just the learning curve is steep.

I have learned so much from one part, it's really amazing!

Highlights of the lowlights:

-Broke only one tool

-Milled two clamps

-Only "ruined" the part once. (Vice was loose)

-Incorrectly input an important number in the CAM setup program 0.04" too short. (my inside cavity is too far right in the x direction (East in machining terms))

-Some mods to the mill are in order to improve accuracy and help deal with the massive pile of chips. (already ordered / researched and on the to do list)

Highlights of success

-Figured out where I need to change my CAD design to maximize mill time.

-Ball mill spacing, the reason for the "waffle effect) on the parts.

-Need to make more clamps and jigs

-Worked out the work flow for part production

-It Effing works!!!!

These shots are the inside of the part. Big waffle pattern because it was cut with a ball mill and the spacing between passes was large, this was purposely done to decrease machine time where finish isn't important. Going forward I'll design / redesign internal cavities to be done with large flat end mills - should save some time.

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Here are the shots of the outside partially machined (to a depth of 3/4"). Still some waffle but it's smoother than it looks, the grooves are maybe 0.005" deep, probably less. Also this portion was done with a 3/16" ball mill. I have mills down to 0.005" so what you are seeing is still something of a rough pass. Irregardless, notice the relief for the panels is visible and more importantly precisely located! Worst case I could pull parts off at this fidelity and hand finish without too much effort.

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The CAD part again in roughly the same orientation so you can compare to the aluminum part.

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Oh yeah and the process takes time, that requires monitoring but not extreme supervision. So maybe, just maybe, I can do the 1/32 T-45C conversion from the Airfix kit Pig gave me.

One day left in the shop before it's off to work, next report soon!

Timmy!

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Last cuts for this trip home.

Completed some fine pocketing - the triangle shape hole that will fit a separate NACA duct. Also a finer finishing test - this time with a 0.040" Ball mill. The fidelity is better. Also I did a test filing of the machine marks and they were easily removed with just a few strokes of the file. I'm looking of a better finish, close spacing of the passes of the cutter and more tuning of the backlash.

I'm done with this test part. I'll be making a low profile vice and adding some upgrades to the mill. The next parts should be finished ones - with at little luck.

This shot shows how the part is buried in the stock - trying to get out.

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These ones so you can see the pocket and test finish.

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