Post by fr8kar on Jan 30, 2020 13:35:59 GMT -5
Several weeks ago Dan posted this thread on casting parts for the radiator section of BN B30-7s. I've wanted to build a decent model of one of the BN booster units for years, but the models always fall short of my expectations. Dan's thread sparked my interest in this model again and I've made some significant progress on it in the past month or so.
The Rail Power Products shell was the best starting point for one of these models many years ago and Smokey Valley ended up making the "cab", the high short hood and a dynamic brake section for them, along with a handrail kit. But SV's dynamic part is too small overall, so it doesn't look quite right. RPP got the hood profile wrong, and SV made their parts to match.
Atlas came out with models of the B23-7 and the B30-7 and offered both Phase 1 and Phase 2 models with different truck centers and other details. I like these models, but I always felt like the corner radius was too sharp. I think the Atlas C30-7 hood is better execution of the GE profile. Years ago before the Atlas B30-7 came out I cut up a C30-7 shell to make a B30-7A, but I couldn't get the Bachmann B23-7 trucks to work for me, so I used that kitbashed shell to build a U33B.
Awhile back I decided to try attaching the SV parts to the Atlas B23-7 model, but the mismatch in hood profile was really bad so I didn't go forward with it. I thought about using an Atlas high nose B23-7 but those look off to me, too. I think that's what Big Dawg or whatever they are called used for their B30-7A1B master. I found one on ebay and made the mistake of buying one. I don't even know where to begin. It's bad.
Eventually when I was working on radiator parts for the C36-7 I got the idea to try drawing up the entire hood for the B30-7A1B. I don't have any data on these, only prototype photos and the Atlas model to start with, so there are guaranteed to be mistakes in my CAD file. Here's a screenshot of the in-progress 3D model from about a year ago when I stopped working on it:
A few days ago I received an order from Shapeways including the B30-7A1B body kit. I've designed it to fit on an Atlas B23-7 sill and reuse the radiator frame and photoetch screen from the Atlas model. Based on the production date of the prototype, these would be Phase 3 so the truck centers are different from the Atlas Phase 1 and Phase 2 models, but even more problematic is Phase 3 units are a foot shorter in length overall. This can be ignored and it won't affect the fit of the hood to the sill. Alternately, the sill can be shortened by removing 6" from each end just inboard of the stepwells. This requires modifying the frame or replacing it, and the latter is what I chose to do. Here's the printed nylon frame with the printed acrylic fuel tank:
The next few photos are of the translucent acrylic parts that make up the body kit. They're really difficult to see until they are painted, but I don't like to paint the parts until after the model is assembled. Here are the parts cleaned up and arrayed as they will be assembled. Each part is keyed so that alignment between the parts is not an issue:
And the assembled model:
Since that's so hard to see, here is the body primed. I haven't done anything at this point to clean up any print lines or rough edges. Also, the shell is just placed on the sill, which has been shortened by the time of these photos but I hadn't filled in the slots where the cab attaches or added any of the detail parts yet:
The Tamiya primer kinda filled in the area around the sand filler doors a bit (on both ends) but that's really the only place it got thick. The door latches are drawn to scale, so they don't pop perhaps as well as they could. And not every part of the printed model prints as well as it could. Some details are soft in some places and crisp in others. I draw each detail once and copy/paste it all over the model, so it's not a problem with the drawing. Anyway, I am happy with how nicely the batten strips and grille details printed, though, especially the dynamic intake and exhaust grilles. Now I need to add the various detail parts: grabs, lights, sand filler hatches, exhaust (Hi-Tech 6001), steps, etc.
Back to the frame for a moment... I designed it for a Kato HM-5 motor with hex flywheels and Athearn trucks since Athearn sells so many different lengths of hex shafts it's possible to replicate the different truck centers on GE diesels built in the 80s. The biggest weakness of this system is that the only sideframes compatible with the Athearn trucks are the Smokey Valley FB-2s. They are terrible. The FB-2 sideframes from the Atlas U23B and later B40-8 are much better but they can't be mounted on Athearn trucks. So I've created an adapter to fit the Atlas sideframes to the Athearn B truck:
There's lots more to come on this build. I'll update it as I make more progress.
The Rail Power Products shell was the best starting point for one of these models many years ago and Smokey Valley ended up making the "cab", the high short hood and a dynamic brake section for them, along with a handrail kit. But SV's dynamic part is too small overall, so it doesn't look quite right. RPP got the hood profile wrong, and SV made their parts to match.
Atlas came out with models of the B23-7 and the B30-7 and offered both Phase 1 and Phase 2 models with different truck centers and other details. I like these models, but I always felt like the corner radius was too sharp. I think the Atlas C30-7 hood is better execution of the GE profile. Years ago before the Atlas B30-7 came out I cut up a C30-7 shell to make a B30-7A, but I couldn't get the Bachmann B23-7 trucks to work for me, so I used that kitbashed shell to build a U33B.
Awhile back I decided to try attaching the SV parts to the Atlas B23-7 model, but the mismatch in hood profile was really bad so I didn't go forward with it. I thought about using an Atlas high nose B23-7 but those look off to me, too. I think that's what Big Dawg or whatever they are called used for their B30-7A1B master. I found one on ebay and made the mistake of buying one. I don't even know where to begin. It's bad.
Eventually when I was working on radiator parts for the C36-7 I got the idea to try drawing up the entire hood for the B30-7A1B. I don't have any data on these, only prototype photos and the Atlas model to start with, so there are guaranteed to be mistakes in my CAD file. Here's a screenshot of the in-progress 3D model from about a year ago when I stopped working on it:
A few days ago I received an order from Shapeways including the B30-7A1B body kit. I've designed it to fit on an Atlas B23-7 sill and reuse the radiator frame and photoetch screen from the Atlas model. Based on the production date of the prototype, these would be Phase 3 so the truck centers are different from the Atlas Phase 1 and Phase 2 models, but even more problematic is Phase 3 units are a foot shorter in length overall. This can be ignored and it won't affect the fit of the hood to the sill. Alternately, the sill can be shortened by removing 6" from each end just inboard of the stepwells. This requires modifying the frame or replacing it, and the latter is what I chose to do. Here's the printed nylon frame with the printed acrylic fuel tank:
The next few photos are of the translucent acrylic parts that make up the body kit. They're really difficult to see until they are painted, but I don't like to paint the parts until after the model is assembled. Here are the parts cleaned up and arrayed as they will be assembled. Each part is keyed so that alignment between the parts is not an issue:
And the assembled model:
Since that's so hard to see, here is the body primed. I haven't done anything at this point to clean up any print lines or rough edges. Also, the shell is just placed on the sill, which has been shortened by the time of these photos but I hadn't filled in the slots where the cab attaches or added any of the detail parts yet:
The Tamiya primer kinda filled in the area around the sand filler doors a bit (on both ends) but that's really the only place it got thick. The door latches are drawn to scale, so they don't pop perhaps as well as they could. And not every part of the printed model prints as well as it could. Some details are soft in some places and crisp in others. I draw each detail once and copy/paste it all over the model, so it's not a problem with the drawing. Anyway, I am happy with how nicely the batten strips and grille details printed, though, especially the dynamic intake and exhaust grilles. Now I need to add the various detail parts: grabs, lights, sand filler hatches, exhaust (Hi-Tech 6001), steps, etc.
Back to the frame for a moment... I designed it for a Kato HM-5 motor with hex flywheels and Athearn trucks since Athearn sells so many different lengths of hex shafts it's possible to replicate the different truck centers on GE diesels built in the 80s. The biggest weakness of this system is that the only sideframes compatible with the Athearn trucks are the Smokey Valley FB-2s. They are terrible. The FB-2 sideframes from the Atlas U23B and later B40-8 are much better but they can't be mounted on Athearn trucks. So I've created an adapter to fit the Atlas sideframes to the Athearn B truck:
There's lots more to come on this build. I'll update it as I make more progress.
