ghodges Posted January 20 Report Posted January 20 This will be my 2nd stab at scratchbuilding a model. It's seems to be more seldom done these days since there's SO many kits available that weren't out there just 10yrs ago. Still, there ARE still gaps, especially in 1/48, which is my primary scale of choice. This will take more time than my usual builds and it will be easier to post progress as I go along as opposed to trying to post everything at once at the end. This the Martin T4M-1. It's never been made in 1/48 in vacuform or resin to my knowledge. I've seen 2-3 scratchbuilt over the last 40yrs, but no kits have been produced except in 1/72. After finding some suitable plans I had them enlarged to 1/48. You can see the two pieces cut out of the plans laying under and beside them. I started by first gluing two blocks of balsa together with a sheet of copy paper trapped between them, using white glue. This allows the two "halves" to later be pried apart. Then those cut out plans were taped to the top and side of the balsa and it was cut to the rough shape seen above on a scroll saw. Note that I actually forgot the "dip" for the 3rd cockpit opening for the gunner's position and had to add that later! The two rough halves seen above were then glued back together and the fuselage was sanded to shape. I used rough and medium grit sanding sticks for this step. Although I did cut out one of the side view templates (as seen on the left in the first pic above) to check the shape as I went, I actually found it easiest to just use "mark-1 eyeball" for 90% of the work. I'm satisfied the outline matches the drawings close enough for "government work"! The over-arching idea here is to make a fuselage that can be split back apart into 2 halves that will be used to vacuform the fuselage in plastic. Next up were the wings. I decided to use the KISS principle and just carve them from solid balsa. The wing thickness on the plans is 1/4", so I used a sheet of 1/4" balsa. I decided not to vacuform the wing parts, but to simply use them as "cores" and wrap them in very thin sheet plastic (more on that below with the tailplane surfaces). Luckily for me, the top and bottom wing of the T4M is virtually identical, so all I had to do was cut out the top wing plan and use it to cut the 1/4" balsa sheets to shape on the scroll saw. The next step was to give the block balsa wings their airfoil shapes. The first thing to do then was to draw a center line in fine tipped black marker around the edges of each sheet. Since I also had a 1/8" sheet of balsa handy, it was used as a template to draw the lines. Those center lines would help me judge the evenness of my sanding as I progressed, especially on the trailing edge since both the top and bottom rear surfaces had to taper down exactly to that rear center line! The leading edge was easily done as all it needed was simple "rounding", which was done with sanding sticks. I taped a large sheet of 80grit sandpaper to the front edge of my workbench to do the heavy sanding on to work on getting the airfoil shape. Again, I just used "mark-1 eyeball" to sand a tapering surface on the top and bottom. I switched back and forth between them frequently always trying to sand just as much on one as I'd just done on the other; and to also maintain the same angle I was holding the piece at while sanding. Once again, I found this easier than expected and the heavy 80grit paper helped speed the process along. Once both were sanded to shape I only had to add the pilot's cutout in the center to make the "top" wing. One part of scratchbuilding is knowing you have to engineer things that kits give you. I had to figure out HOW I would attach the bottom wing to the fuselage. Again, trying to go the simplest way, I decided to cut the airfoil shape into the fuselage bottom so the wing can be fit up into it. The scroll saw has more than earned its keep on this project! I tackled the tail surfaces next. Since they're smaller I decided to use thick sheet plastic to carve their blanks. After transferring their plan shapes to the sheet plastic heavy scissors was used to cut them out. They were then hand sanded to their airfoil shapes just like the wings. Note the very thin piece of .005 plastic sheet at the top of the pic. This was what I'd use to "skin" them with, so I didn't have to worry about any sanding marks on the plastic blanks. This and the following pics will show the method used to make the ribbed skinning for the horizontal tailplane, but the same method was used for the fin and rudder too. Note that the tailplane plan has been drawn in pencil onto the .005 plastic sheet, including the "rib" lines. Also note that they do not go all the way to the edges of the drawing/part. The .005 sheet was then placed onto a folded piece of paper towel to give it a slightly padded surface under it. A straight edge and a ball point pen was then used to draw in the rib lines (whether or not the ink transfers to the plastic is not important). This method creates an indented line on the inside and a raised "rib" on the outer surface of the thin sheet. Here, the tail plane blank (which had already been used in 2 previous failing attempts at ribbing!) has been superglued to the first half of its "skin". After it set, more superglue was applied to the other half and it was folded over onto the top. This method isn't perfect.... it produces rough edges at the sides and rear, but those can be carved and sanded to shape. On one of my first attempts I tried using contact cement instead of superglue. It worked ok, BUT when it came time to sand it and the .005 was sanded through, the contact cement did NOT sand well. Superglue solved that problem! Here are the rough sanded and primed tail plane parts. I'm very satisfied with the representation of the structural ribbing as being even and visible enough for my purposes. I believe that once they've been fine sanded and painted they'll look the part, pun intended! That's where things stand as of today! My next step will be to try to "skin" the wings. More pics when more progress has been made. Comments, critiques, questions, and suggestions are all welcome as always! Gil 2
Ron Bell Posted January 20 Report Posted January 20 You are getting ambitious in your golden years! I had the Esoterica vacform model of this and just never got around to building it. So far yours is looking good, Keep us posted.
ghodges Posted February 23 Author Report Posted February 23 (edited) Ok.... after the debacle of diverting to build the RF-84F, I'm back to work on this 1/48 Martin T4M torpedo bomber. I started by making a 3rd tailplane, as the first 2 just didn't cut it. I tried to "carve" the ribs on the far left one and that was too rough looking. I used the skinning method on the center one, but it had some gunk under the skin when I folded it over that resulted in having to try to sand the ribbing which ruined a section. It seems the 3rd time was the charm! The far right shows the 3rd tailplane I've built by sanding thicker sheet plastic to airfoil shape and skinning it with with "drawn ribbed" .005 sheet plastic (as seen in the post above). This one has much more consistent ribbing. Since I'd had trouble before trying to scribe the elevon hinge line, this time I sawed the elevons off of the tailplanes, glued some half-round to their leading edges, and carved a groove in the rear edge of the tailplane so that the elevons fit snuggly into that groove when I reattached them. I also realized that according to the scale plans the tail fin does NOT sit on top of the tailplane; instead, the tail plane is mounted on either side of the tail fin just below the lowest rib. So, that meant cutting out the center section of the tail plane (the thickness of the tail fin) and drilling holes so I could use thick wire for mounting pins. This pic shows test fitting each tailplane half to the fin. Not absolutely perfect, but certainly workable! Front and rear views of test fitting the tail fin and tail planes to the balsa fuselage (which will be vacuformed in the end). Moving to the wings.... I realized the wings AND the ailerons would be easier to skin if they were separate, so I sawed them apart. I also reasoned that the center of the bottom wing, where it's attached to the fuselage, the landing gear, and where the torpedo hangs would probably be the most heavily reinforced wing area so I used .010 sheet plastic with no ribbing to skin it. I used "ribbed" .005 sheet for the upper wing section, but note that I had to leave a space for a wing tank (the blue rectangle) when drawing in the ribbing. All that's left now is to use the .005 sheet to skin the rest of the wings and also skin the ailerons! By the way.... I'm using Gorrilla brand contact cement to attach all of the skinning. It only takes 2-3 minutes after applying before it's ready to use. BUT, it is NOT designed for "polystyrene", so it has to be used only in thin coats, which is exactly what's called for in this build. It seems to sand better than the regular "wood working" contact cement I first tried and gives me slightly more working time than using superglue. Critiques, questions, and comments welcome as I stumble forward with this project! 😁 Gil Edited February 23 by ghodges 3
ghodges Posted March 3 Author Report Posted March 3 I finally got the the wings and the ailerons skinned and assembled. This is their first overall coat of primer. A lot more fine sanding and more primer will be needed to even out some of the surface imperfections. It's a learning process and I don't expect to get all of the anomalies out of the surfaces; just most. Overall I'm satisfied since at least they do look like wood and fabric wings! By the way.... these are the top surfaces of each wing. I'll turn them over and primer the other halves tomorrow!\ Gil 1
ghodges Posted March 11 Author Report Posted March 11 Some more details have been added to the wings..... The 4 wing fold panels have been scribed in, their hinges added, and another coat of primer sprayed on. The hinges were made by sawing notches every 1/16" along a piece of half-round plastic strip. Note that hand holds have also been drilled out in the wingtips of the bottom wing. There's still yet MORE filling and sanding to be done, as evidenced by the one seam line running down into the one wing fold panel and some other slightly marred spots here and there, but little by little the wings are getting there! 2
ghodges Posted March 17 Author Report Posted March 17 (edited) Some more progress pics of scratchbuilding my 1/48 T-4M torpedo bomber. Made a big step forward in getting the outer wing struts made and test fitted. Looks like I might just be able to make a model out of this after all! Test fit of the struts and the wings with the fuselage in place for reference. I'm pleased with the "look" overall. This rear view seems to confirm that the struts have been placed evenly and symmetrically. A close look at the wing surfaces shows the pencil lines drawn on and used to mark the exact strut placement points. The struts are airfoil strip stock cut to identical lengths and drilled and pinned with thin floral wire. The 3 thicker wires on the bottom wing center line are used to temporarily anchor the wooden fuselage in place for test fitting. You can also see some more of the filling that's been done on uneven scribe lines and minor imperfections that have since been sanded and primered over yet one more time. Anyway, this feels like a major step forward in the project and is a great motivator to move on to building the landing gear struts. More pics when they're done! Comments, questions, and critiques welcome, as always! Gil Gil Edited March 17 by ghodges 1
Ron Bell Posted March 17 Report Posted March 17 Where did you get the airfoil strip stock? I have some really old stuff I'm hoarding but can't find any new supplier. I've used aluminum stuff but it doesn't come in smaller sizes.
Nick Filippone Posted March 17 Report Posted March 17 Ron, I share your anxiety about airfoil cross-section strut stock. I too am hoarding some but I have not found a new supplier for years. I have long hoped that Evergreen would offer it but nothing so far.
ghodges Posted March 17 Author Report Posted March 17 I have a most of a bag of what I believe was made by Contrail back in the day, with a variety of widths and all about a foot long. I also have a drawer with left over strut stock (including some sturdier types) but they're all 3"-6" long; which may do for trying to make the landing gear legs. I don't know of anyone who makes and sells extruded airfoil strut stock these days. It sounds like JUST the thing an enterprising 3D printer could make and sell though! The market for it is much smaller these days than 20-40yrs ago, but it is still out there. Gil
ghodges Posted March 19 Author Report Posted March 19 Got the main landing gear built for the T4M-1 torpedo bomber. Each one consists of 11 pieces of airfoil strut, wire, and a small bit of tubing. More pics after I get the tail wheel built! Gil 1
ghodges Posted March 21 Author Report Posted March 21 I'm pronouncing "phase 1" of my scratchbuilt 1/48 Martin T4M-1 torpedo bomber as done! These pics show the wings, empennage, and landing gear mocked up with the balsa fuselage. I went this route reasoning "why bother vacking a fuselage if I couldn't build the rest"? Now I believe it's time for phase 2 and to turn my attention to the fuselage to determine what details need to be added before splitting it apart to be vacked. More pics after THAT's been done! Gil 1
ghodges Posted March 22 Author Report Posted March 22 Found a boo-boo in my build.... I JUST found a small anomaly in my T4M-1 build.... evidently there should be NO REAR inner vertical wing struts, as seen in the pic above! The lack of a vertical strut at the rear of the wing fold break is something I should have noticed earlier. The plans I have do not have a "rear" view and the rest of the plans imply that the struts would be there like most other biplanes of that time. But after studying pics of the real thing, they're just not there! Luckily it's an easy fix at this point! Just leave them off! It always pays to quadruple check your references! Gil 1
ghodges Posted March 31 Author Report Posted March 31 (edited) Still inching along on the torpedo bomber..... Got the nose cut off of the fuselage and glued sheet plastic to it to add the flat panels around it. I felt this would be easier than trying to sand each area of the nose AND keep the panels symmetrical. These 2 pics show the fuselage halves after having been split back apart along the original glued paper divider and also the angles of the nose panels on its sides, top, and bottom. Sometime scratchbuilding a model requires more than just building the model.... in this case I needed to make adjustments to more efficiently use my vac table..... I have a BIG table, measuring 22' wide x 28" long! This will come in very handy for one future project I have in mind, but it's MUCH bigger than needed for this torpedo bomber and would waste a lot of sheet plastic. Note the marked off rectangle in the center..... this is where a smaller raised platen will go to vac my parts. All of the holes outside of that area will have to be sealed with tape. The answer is to vacuform smaller sheets of plastic.... big enough for the parts, but not as big as the table. I found a metal document frame at Walmart that's 11"x14" and took all of the glass, matting, and other stuff out of it to leave the bare frame. The sheet plastic is simply clamped to the frame. This will be popped into the oven to heat the plastic until it sags so I can then throw it on the table and vac my parts (hopefully!). I made a smaller raised "platen" out of peg board to set onto the center of the vac table with holes that match the vac table. I've placed the parts here to give an idea of how they'll look when ready to vac over EXCEPT that they'll each have some material added on their undersides to slightly raise them from the platen so the vacuum can (again, hopefully) circulate a bit under the parts as well as around them. Ain't "do it yourself" fun? Lastly.... you might be wondering where do you get the sheet plastic? You order it from a plastic supply house! This is 5 sheets of styrene (3 of .02 and 2 of .03) rolled up in there, each one 40"x70". Hopefully that'll be enough for anything and everything I might do for years to come! More pics after (AND IF!) I can get this all to work! Gil Edited March 31 by ghodges
Ron Bell Posted March 31 Report Posted March 31 Plus, by shrinking the area, you should get better suction in the remaining holes, no? 1
ghodges Posted April 2 Author Report Posted April 2 A significant step forward! I have vacuform parts! Well.... I pulled about 6-7 shots (more than seen here) on my machine with spurious results..... but I'll reserve final judgement until they're all cut out and I've tried fitting them together. I only need 2 halves to work! The nose was very problematic with the draped edges as seen. Luckily I do NOT need a vac (hollow) nose and can use the master on the model if needed! It's good to know that my vac box, metal frame and clamp system "works" even if the parts look VERY amateurish compared to what you get from commercial vac kit makers! More pics after I get some parts fitted together. Gil 1
ghodges Posted April 3 Author Report Posted April 3 (edited) Started working on the fuselage halves... Sanded these out and then added the alternating plastic strips needed inside the seams to keep the thin edges of the plastic from folding over each other when test fitting the halves together. The plans you see were used to mark and then guide cutting out the 3 windows in each side. Here's the fuselage taped together for a test fitting with the nose in place. All of the window and cockpit holes were first opened with a drill bit. Next, I used a router bit in a motor tool to grind out most of the opening, followed with another conical sanding bit to finish out each opening. I used the lower speed on my 2-speed battery powered tool so to avoid melting the plastic while grinding it away. Gil Edited April 3 by ghodges
ghodges Posted April 4 Author Report Posted April 4 (edited) I've started adding details to the fuselage exterior using strip stock for ribbing, half round rod for hinges, and plastic tape (blue) and sheet plastic for access panels. Hand holds/steps have also been opened up and then boxed in. I may throw a coat of primer on it all just to get a sense of how it'll look under paint. Gil Edited April 5 by ghodges
ghodges Posted April 5 Author Report Posted April 5 Got a couple of major jobs done today.... I got the fuselage windows made. I started by making "rings" to fit on the inside of each window JUST slightly smaller than the opening. This made "seats" that each clear window can later be slid onto which will allow me to add the windows very late in the build. The bottom fuselage has 3 windows sitting in place, and you can see the other 3 windows at the bottom of the pics. They were made with a punch of the appropriate size. I also got the interior tubular frame built. The frame was made using plastic rod and built by fitting parts inside the fuselage and also matching to the plans on hand. It was done partly with measurements and partly by "mark-1 eyeball". There's still more supports to be added for detailing, but this makes up the basic frame. These 2 pics show the test fitting of the tubular frame into the fuselage to be sure it fits ok. There's still a l-o-n-g way to go to build up all of the interior details, but at least I now have a frame to hang everything on and within! Gil
Navairfan Posted April 9 Report Posted April 9 Gil, all I can do is shake my head in admiration at your skills as a modeler. Starting with nothing but an idea, you're able to create such masterpieces. Simply incredible work.
ghodges Posted April 10 Author Report Posted April 10 Started making cockpit parts today for the scratchbuilt 1/48 T4M-1; working on getting the resin seats installed at the right heights, installing foot channels evenly at their correct heights, and making up the control wheels with their actuator/torque tubing. All of this was done pretty much by repeated trial and error test fitting. There's still a lot of other details to be added to the interior yet including the entire rear cockpit. The seats and sticks are designed to be able to be added late in the build. Test fitting the assembly to the fuselage for the seat heights and positions compared to the cockpit openings. More pics when the interior is more or less complete! Gil
ghodges Posted Saturday at 04:59 AM Author Report Posted Saturday at 04:59 AM Most all of the interior parts are built now.... Overall view of this week's work.... If you look closely you can see (front to back) the PE rudder pedals and cables, both of the throttle quads and their cable, the torpedo drop control console/handles bottom right front, the trim control wheel on the left center of the middle cockpit along with an emergency hydraulic pump on the right side, and the Lewis gun ammo drum racks in the back of the rear cockpit. This is a view from the other side where you can see the radio (with a sending key out of view) on its rack in the front of the rear cockpit. Not seen is the pivoting seat for the rear cockpit. The main IPs are being built using the traditional sandwich method. The holes for the IPs where made using a Waldron punch and die set. These assemblies will be sprayed black and then the fronts pried from the backing sheet so the black instruments can then have their individual markings scribed in place. More pics of that when they're done. Gil
ghodges Posted 3 hours ago Author Report Posted 3 hours ago Main IPs are done (or as done as I'm gonna make 'em!).... I started by painting the IPs Tamiya flat black.... I then pried them apart so I could scratch off the markings on each painted black dial..... However! THAT didn't go as well as planned so I switched gears, dug out some Mike Grant instrument decals and punched out each individual instrument and white glued them onto the back of each panel. I then added some spare PE parts and some painted red buttons to finish them up. Interestingly, I believe using the spray can Tamiya flat black may have hindered my initial idea. The scratch-off dial method was originally developed using enamel paint back in the '70s and I think it actually scratches off easier than the Tamiya acrylic/lacquer paint. All I know is I was having more trouble scratching off the paint to make the dials than I have in the past and that's the only difference I could think of. Just file that away for future reference! No pics.... but I also got the interior frame and fuselage interior sides sprayed with their initial coat of metallic aluminum! Perhaps I might have the interior "done" and the fuselage glued together by the end of the week! Gil
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