EMD F7 in SCALE

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Steggy
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Re: EMD F7 in SCALE

Post by Steggy »

rkcarguy wrote:Very nice BDD!
Thanks!
I like the industrial grey you hit all the internals with, makes it look like a workhorse instead of a trailer queen haha
Coincidentally, the company that did the blasting and painting for me refinishes (full-sized) locomotives. They've got literally hundreds of gallons of machinery grey paint on hand at all times. Plus it's an epoxy enamel, so it should hold up well. When I get to doing the body, the interior of it will also be machinery grey.
That briggs "chug" is hard to get rid of isn't it? Granted, its one of the least lawn-mower sounding gas powered loco's I've heard in a long time.
Well, whaddya gonna do when you only have two cylinders making noise? :D The microphone in the camera is not high fidelity by any measure, so what you are hearing is not quite what it sounds like in reality. When it is idling, most of the sound is mechanical noise, not exhaust.

In the first clip, the prime mover is running at 2400 RPM in notch eight while in low transition, explaining the racket. In high transition, the same road speed would be developed in notch four, at which the prime mover is spinning at 1600 RPM. When operated that way the unit has a decidedly locomotive sound to it.

Incidentally, the exhaust goes out the top, same as with the real F-unit.
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Music isn’t at all difficult.  All you gotta do is play the right notes at the right time!  :D
rkcarguy
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Re: EMD F7 in SCALE

Post by rkcarguy »

I hear you on the engine noise. I've noticed when I've shot footage of my karts, that the camera seemed to pick up more of the ticking noise from the engine than the exhaust notes, and it makes it sound worse than it is.
I'm not sure if you have room inside your body, but the insulation system our shop put in some compressor skids was amazing at quieting things up. It was a layer of acoustic foam, covered with a layer of rock wool, with perforated metal panels riveted over it. These skids went from deafening loud, to more like standing next to an idling vehicle.
I am having real exhaust come out my stack as well, now If it was only black exhaust lol!
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Steggy
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Re: EMD F7 in SCALE

Post by Steggy »

rkcarguy wrote:I'm not sure if you have room inside your body, but the insulation system our shop put in some compressor skids was amazing at quieting things up.
Actually, I don't want to make it quieter, and in any case, there's little clearance between the body structure and the machinery. Also, insulation could cause some cooling problems.

The real F7 when idling made quite a bit of racket, much of it mechanical in nature. I've been told by a number of people that mine sounds like a miniature version of the full sized F-unit when idling. Idle RPM is 1000.
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Music isn’t at all difficult.  All you gotta do is play the right notes at the right time!  :D
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Steggy
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EMD F7 in SCALE

Post by Steggy »

EMD F7 in SCALE
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BODY CONSTRUCTION: Part V

One of the most complicated aspects of building the body was fabricating the main (center) roof hatch assembly.  A number of pieces are part of the assembly, including the hatch itself, fan deck, exhaust stacks, reinforcing ribs, fan adapters (yes, there are functioning fans) and fan grilles.  Excepting the grilles, all parts are fabricated from sheet steel.

Main Hatch Sheet After Rolling
Main Hatch Sheet After Rolling

Above is the main hatch sheet after rolling.  The fan deck fits into the rectangular opening, as well be seen in a later picture.

Fan Deck w/Rib Jigged
Fan Deck w/Rib Jigged

Above is the fan deck with one of the supporting ribs jigged in place.  These ribs extend under the main hatch sheet to tie the structure together.  The ribs are a bit of overkill in terms of material thickness, but that extra mass helps to prevent distortion during welding.  Additionally, I wanted the hatch to have sufficient strength and rigidity to allow it to support the weight of the body when mounting it to, or removing it from, the chassis.  The ribs’ ability to distribute load forces into the rest of the hatch would be essential to that requirement.  A photo in a future post will show how I handle the body when it isn’t mounted on the chassis.

Fan Deck w/Ribs & Exhaust Stacks
Fan Deck w/Ribs & Exhaust Stacks

Above is the fan deck after the supporting ribs and exhaust stacks had been attached.  A lot of care was taken to get things as accurately positioned as possible, since the main hatch is a point of detail that is immediately visible to the casual observer upon seeing the locomotive for the first time.

Once I had finished the fan deck fabrication, it quickly became apparent that a simple fixture would be a big help in getting everything lined up for welding.  So I got busy.  :D

Main Hatch Welding Fixture
Main Hatch Welding Fixture

This fixture was fabricated from a piece of extruded aluminum tooling plate drop that I obtained from a local machine shop.  It was a bit too long, but I was able to put this piece into my (9" × 13") horizontal band saw and shorten it to the required dimension.  I fabricated some clamping bars out of 1/2 inch thick cold-rolled I had laying around.  The two large holes bored through the plate give clearance for the exhaust stacks when the fan deck assembly is in place.  The clamping bars then secure the deck to the plate, with bolts threading into four tapped holes in the fixture.

Main Hatch in Welding Fixture
Main Hatch in Welding Fixture

Above is what the hatch assembly looked like after jigging.  The cutout in the center of the hatch naturally pilots on the deck’s perimeter, which made achieving alignment fairly easy.  A long piece of rectangular tubing acts as a clamping bar to hold the entire mess in alignment, along with the usual army of C-clamps.

As all of the sheet metal pieces are 16 gauge, I used 0.025 inch wire in my MIG welder, along with 75/25 shielding gas, and skip welded the joint between the deck and the hatch sheet, keeping in mind that cosmetics would be important.  Somewhat-heavier welds were made to attach the ribs to the hatch sheet.  These welds produced some localized distortion that would be visible on the exposed side of the hatch, which was not necessarily a bad thing—such distortion can be seen on the hatches of the real F-units.

The next post will have some pictures of the completed weldment.
Last edited by Steggy on Tue Dec 12, 2023 4:25 pm, edited 1 time in total.
———————————————————————————————————————————————————————
Music isn’t at all difficult.  All you gotta do is play the right notes at the right time!  :D
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Steggy
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EMD F7 in SCALE

Post by Steggy »

EMD F7 in SCALE
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BODY CONSTRUCTION: Part V cont'd

Below are some pictures of the completed main hatch assembly.

Main Hatch Assembly After Welding
Main Hatch Assembly After Welding

Main Hatch Assembly with Fan Grilles
Main Hatch Assembly with Fan Grilles

Closeip of Fan Grilles
Closeip of Fan Grilles

Main Hatch Assembly Primed
Main Hatch Assembly Primed
Last edited by Steggy on Tue Dec 12, 2023 4:26 pm, edited 1 time in total.
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Music isn’t at all difficult.  All you gotta do is play the right notes at the right time!  :D
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NP317
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Re: EMD F7 in SCALE

Post by NP317 »

Quality work!
Your careful fixture and setup is commendable. And time-consuming.
~RN
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Steggy
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Re: EMD F7 in SCALE

Post by Steggy »

NP317 wrote:Quality work!
Thanks!
Your careful fixture and setup is commendable. And time-consuming.
You'll get no arguments on the time-consuming part. :D There is other tooling and fixturing I made to build up other body subsassemblies, as well as items such as the frame, trucks, etc. Aside from the desire to achieve reasonably accuracy, somewhere way back in my head I have this idea to also build a fully functional B-unit. Just about all of the tooling that I have made to build this unit will come in handy should the B-unit ever make it from fantasy to reality.

Speaking of fixtures and such, if I can ever find them I will post the pictures in which I used a Black & Decker laser level device as an alignment indicator for building up the frame.
———————————————————————————————————————————————————————
Music isn’t at all difficult.  All you gotta do is play the right notes at the right time!  :D
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Steggy
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EMD F7 in SCALE

Post by Steggy »

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Music isn’t at all difficult.  All you gotta do is play the right notes at the right time!  :D
Andrew Pugh
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Re: EMD F7 in SCALE

Post by Andrew Pugh »

It's great to see you updating your build thread BDD.

Your F7 is looking great!
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Steggy
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Re: EMD F7 in SCALE

Post by Steggy »

Andrew Pugh wrote:It's great to see you updating your build thread BDD.

Your F7 is looking great!
Thanks!
———————————————————————————————————————————————————————
Music isn’t at all difficult.  All you gotta do is play the right notes at the right time!  :D
WJH
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Re: EMD F7 in SCALE

Post by WJH »

That is a beautiful F body!
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Steggy
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Re: EMD F7 in SCALE

Post by Steggy »

WJH wrote: Tue Jan 30, 2018 9:46 pmThat is a beautiful F body!
Sorry for the belated reply, but thanks! Health woes have "grounded" me and an endless parade of doctors, nurses and therapists have replaced trains for now. :roll:
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Music isn’t at all difficult.  All you gotta do is play the right notes at the right time!  :D
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