khodges

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Chic, the material the templates are made from is X-Ray film. It's going the way of the dinosaur, most hospitals are converting to digital films and the stuff is getting scarce. I get one of the techs in the radiology dept. at work to save the test films, they come out with the film clear and it makes great pattern material because you can trace through it and it is very durable. I don't have much left, not sure if I can get any more. On those templates, the large notch for the crutch should be left uncut until you get ready to actually glue the former in place, as the location may vary a bit from the plans. My kit was laser cut by Precision, and is well done, but the notches are a tad off from the plans. I think it better to match the former to the plans and mark the notch more precisely for a tighter fit. The #6 is probably okay, and the one I re-cut, #5, is the one to watch, as the former fits at an angle to the crutch, but the slot is cut square to the wood, which is probably what makes it a tad off.

I glued #3 to one of the fuse sides tonite, after laying the sides/crutch out on the plans and marking the locations of the other formers on the crutch. What I spoke about above, the notches for the formers being off, is really applicable to #3 and #5 more than the others, because they fit on the crutch at an angle. Since the formers have doublers along the edge that make them thicker, the notch must be trimmed at an angel that matches how the former fits. Since I learned this the hard way, my notches are a little big and I have a small gap around the crutch on them. When I glued #3 down, I also mixed a little epoxy and added some milled fiberglass to it to make a "putty" to fill those gaps. So-- the former is glued with epoxy at the crutch and bottom brace, but aliphatic along the sides of the former. The former is kept vertical to the fuse side by using a small carpenter square taped in place while the glue dries, and the former is weighted with whatever heavy items are around to make a tight bond.

One thing I did befor gluing up the former was to dry-fit the three cabin formers to see just how well, if at all, my modification to #5 worked. Keep in mind that this is just a mockup with the clamps holding things in place, but you can see that it really changes the wing root and rear of the cabin.

redtail

My Feedback: (15)

Ken, those mods really look good and certainly a huge boost to the scale outline. I certainly don't see why there should be any structual integrity issues at all with the new changes. Keep it up. Chic

AIRPLANENUTS

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Ken, I just stumbled on this thread tonight. Terrific! I'm glad you're building the Bird Dog, my favorite plane. I've wanted one for years. I wish I had the time to build one for myself. Keep up the great work.

Rick

khodges

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Rick, thanks for the interest. Keep checking in, make sure I'm doing it right. You know how it is when you know what you want to do, but just can't make it work, or it don't come out quite like you thought?. I started wondering today if that was going to be the case; had me a bit of aggravation this afternoon. I was fooling with the partial frame-up of the cabin trying to get an idea of how I wanted to proceed with putting in former #5, and I broke one of the crutches, right where I had scarf-jointed them. The wood broke, not the joint, but it is in a spot that will have some tension on it until I can get the cabin framed up completely and the glue dries. So...... I epoxied the crutch at the break, and laminated a piece of carbon fiber tape over the joint, and just in case, I duplicated the carbon fiber over the other scarf joint (picture 1)

The plans don't call for any, but I added doublers to #5 down the long sides and at the bottom, to strengthen it and give a bit more glue surface. When I dry-fit it, there is a LOT of pull from the sides, resisting how the former narrows the fuse. I decided to relieve the crutches between #4 and #5, so I made 3 kerf cuts on each one, just behind #4. Once the cabin is framed and dry, I'll put a bit of the carbon fiber over the kerfs for strength. (also pic #1)

I started the cabin frame-up by gluing #3 to one fuse side, making sure it was perpendicular to the side. Then I stood it upright and glued the other cabin side to #3, also making sure it was perpendicular and that the crutches were parallel. Then #4 went in after aligning it, squaring, etc and clamps were applied and I took a break and let the glue dry. After this is when I broke the crutch.

I also decided to epoxy #5 former, as there is alot of stress there. Got it all glued in and clamped (think I used enough clamps?), and then I also installed the top braces at each of the formers and clamped them down, too. I checked the squareness by measuring the diagonals from each corner made by a former. Between #4 and 5, it was off about 3/16", so I added a diagonal clamp to hold it square until the glue dries. It'll sit overnight, and I'll start again tomorrow.

redtail

My Feedback: (15)

Hey, I thought I had brought all the clamps that Harbor Freight had in stock. Looking good Ken, looking good. Chic

khodges

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Didn't do as much as I wanted today. It was nice outside, so I went flying for about half the afternoon. Took my Bud Nosen Trainer, which looks kind of like a cross between a BirdDog and a C170. US-41, 96" wing, 22 pounds; it flies like I hope the L-19 will.

I attached formers #1 (firewall) and #2 (instrument panel). The firewall got epoxy, plus I cut a 1" square hardwood stick into two triangular pieces with my bandsaw, sanded one side to match the curve of the fuse sides, and epoxied them into place in the corners. This firewall ain't going anywhere. The inst. panel was aligned and glued and when the firewall was clamped tight it pulled the fuse in a bit and held the inst. panel tight.

While the front end was curing, I leveled the crutch and glued formers #6-10 in place, making sure they were vertical, or perpendicular to the crutch, and also perpendicular to the vertical centeline of the fuselage. I also marked the centerline of the fuse on top of the cabin formers, #3,4,&5, and layed a stick in the stringer notch on top of the rear formers. Then I sighted down the marks and down the stick to ensure that the fuse was aligned front to back. I had made a sort of jig to set the fuse in just so it would sit flat on the table and to support the rear ends of the crutches.

khodges

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Chic, here's the pic I was going to e-mail, I don't have your address:

khodges

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Today, I got the landing gear plate in place, the tailwheel mount in place, and a couple of longerons and formers. It took all afternoon; I had to re-cut the landing gear plate because the one that came from Precision was not cut perfectly square and was 1/8" narrower than it should have been. It would have worked, but the fit wasn't as close as I wanted. I didn't have any 1/2" ply, so I glued up two pieces of 1/4". It doubled the layers, so maybe it will be more solid, not that anything else but the gear plate would survive in a crash anyway[&o]. I had to get creative with my clamps to hold it tight and pull the bottom of former #3 tight to the front of it. I epoxied this plate, but used aliphatic on the smaller triangular piece for the tailwheel mount. It, too, was undercut a tad, but less so and I used the one supplied by Precision. I'm proud of myself so far; I haven't used a single drop of Ca yet

I also glued the bottom main longeron to help stabilize the tail until I get the rest of the longerons in place. When I pressed it in place, I noticed it did not want to rest in the slot in #5, and if I forced it into position it gave the smooth transitional curve along the fuse bottom a slight dip. I checked my full-scale reference pictures and the natural curve the longeron wanted to make is the correct profile. To make it fit properly, I cut a piece to fit the bottom of former #5, revising its bottom curvature (note the line on the piece showing the original curvature, about 3/32" difference), and glued it to the base of the former, like a doubler. Now the longeron fits like it should, and the profile of the fuse stays like it should. I'm not sure why the former came out like it did, I cut the bottom exactly like the original (this is the former I modified earlier to make the cabin rear closer to scale.

To finish up tonite, I glued formers 3a and 3b to the bottom of the fuse at the landing gear plate. Looking at the space that will be covered over betwen the gear plate and the outer skin, between 3a and 3b, I might try utilizing the space for at least the Rx battery. A "trapdoor" on the underside there should be easily camoflaged, and give access to the battery pack; a small hole in the gear plate can be used to pass the wiring through. This is directly under the C/G, and would allow one less thing in the cockpit that needs hiding. Right now, I plan to put the elevator and rudder servos at the location shown on the plans, just forward of #5. This would put them behind the rear seat, so they won't interfere with scaling out the cabin interior.The Rx will also go back there I hope; I'm using 2.4GHz so I don't have to worry about antenna routing. The ignition battery and throttle servo hopefully will go in the engine compartment.

redtail

My Feedback: (15)

Ken, I did put a trap door sort of speak under the plan location for the elevator and rudder servos to give me direct access to them instead of going through the scaled out cockpit to get to them. Wish I had thought about using the area between the landing gear legs as another trap door. Would have been smart for access to batteries or something, again, to cut down on going into the cockpit area. Got a bit antcie and added the step and an open vent on each side of the cowl last night. Did not have alot of time to work. Will finally sand and glass the wings this week. Ken, your build is looking awful good and your being very smart about it. Chic

khodges

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I hadn't really thought about getting to the servos, not a bad thought, so I'll probably look into that as well.I think that I can hide both by using the panel lines in that area to conceal the access panel edges, One other things I plan to do; the filler that fits over the landing gear, I will make as a removable plug. Invariably at some time the gear will need removal for repair. I did the same thing to another plane I had with similar gear mount, it worked well and was not very noticeable, and I wasn't trying to conceal it on that plane. I'm not sure if I'll get anything done today, will post pics if I do.

MJC0074

Hello All. Has anyone here built the l-19 by Bob Rich? Im currently having serious trouble with the fuselage formers. Nothing seems to fit. Please if anyone can help. Photos Info Whatever. Thanks. [email protected]

khodges

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Wish I could help, MJC. I don't know anything about those 'Dog plans. I didn't know Rich had plans for the 0-1, what scale is it?

It's been a few days, I've gotten most of the basic fuse structure done, plus some early detail prep. The fuselage formers don't all have doublers, but they are in the scale position in the structure, so I added balsa doublers everywhere and sanded the corners rounded off so I can create the illusion of aluminum box structures when I finish detailing the cockpit.

When I got all the longerons glued in, and measured, everything was spot-on in alignment, but the #7 former made a small "dip" in the top of the rear fuse. After comparing to the plans, I determined the rear was right on, and the #6 was also right on. I think the #7 must have been undercut along the top by about 3/32", just enough that it would be noticeable after the fuse is skinned; I cut some thin strips and glued them along the top longerons and then sanded them level, so everything is flat, and then made some balsa fillers for the former so all the glue surfaces for the skin match up. It didn't take as long as I thought, but it sure makes a difference when you sight down the fuse and see how straight everything now is.

I also routed the elevator and rudder control rods, and made the exits at the rear in the scale locations. These are Sullivan rods, semi-flexible and are carbon impregnated. I find they are extremely stable and aren't affected by temp. changes. I will use a solid pull-pull for the rudder, except the last few inches that exit the fuse will be cable, as in the prototype. I need to drill some holes in the main gear plate to mount blind nuts for the gear, and also at the tailwheel block. I plan to use parts from a Sig tailwheel assembly. It has several spring steel leaves like the full scale. I have a Klett tail wheel and stirrup for now, but I want to look around and see if there's anything I can get that's more scale, or look into having a friend make one from chromemoly, like he did for my UMF WACO.

Just for kicks, I also weighed what I have so far. Comes out to 3-1/2 pounds, not bad.

redtail

My Feedback: (15)

Hey Guys, something to consider this early in your build. I'm sitting here in the shop looking at the "Dawg", my wife has kept me tooooo busy to work on it, and while looking at my work, I clearly noticed that I had mounted the cowl with the mounting bolts visible on the cowl sides. Typical of RC models but not so scale, so before the game starts this evening, I will have remounted the cowl with the mounting bolts hidden inside the cowl. They will be accessible through the intake holes in the cowling. I plan to put a piece of window screen (black) in all four intakes (velcro mounted) and have the bottom outside corner of the top two intakes loose to allow me to put a ball wrench through and into the cowl to reach the cowl mounting bracket bolts on the fire wall. I will have to repair the eight holes I drilled into the cowl but that will be minor compared to seeing the unsightly four bolts I had clearly visible on the sides of the cowl. Go Atlanta Falcons, ooops, they are also home watching the game on TV like I am. Chic

khodges

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Good point, Chic, and that's what I'll do also. I am planning on fiberglassing an inner "lip" on the cowl, so when it's mounted the lip fits against the firewall on the inside, and the screws will fit through this lip into the cowl.

Things seem to have slowed somewhat, I worked most of yesterday morning and last night and a bit this morning on putting the cockpit floor in and making the box for the fuel tank. I'll post a few pics later tonite with descriptions.

I was at the field both yesterday and today, nice weather for flying. Turns out that there's a guy in the club, one of our older members (both in age and long time in the club) who is building TWO of these at the same time, both 1/4 scale. I had my fuse at the field yesterday, and he brought one of his today. We're at almost exactly the same point in the build, but he's doing two at once. Of course, he's been retired for years, whereas I have to work (around building airplanes). We'll have a squadron of these things.

khodges

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here's the latest. The floor is placed in three pieces; the forward section, from former #3 to the firewall (#1) is glued in place. The middle piece, and largest, goes between #3 and #4 and will be removable to give access to the Rx, batteries and Rx operated engine kill switch. The rear piece goes behind #4 and ends before it gets to #5 and is glued in place. There will be an open area to mount the rudder and elevator servos. This is directly behind where the rear seat will be. The floor is mounted 5-1/2 inches down from the bottom of the front side windows; this puts the floor at the bottom edge of the door, in case you make the door operable. I plan to, but it will be a while before I cut it loose.

There is enough room under the middle section and the landing gear plate for a couple of "sub-C" battery packs, and a small deeper area for the Rx and other electronics. I made a sub-floor on the inside of the longerons from 1/32 ply in this spot.

The box for the tank is made from 1/8" lite ply, as is all the floor sections. The tank box fits inside the square hole in the firewall and extends back to former #2 which is the instrument panel. The tank will also extend into the engine mounting box, which will mount to the front of the firewall. I also made brackets to fasten the engine mount box. I used four #8 socket screws on each side; the plans called for three #10's (I didn't have any[&o]). I also made the brackets 1/2" longer than the plans called for, and mounted them 1/4" wider apart than the plans called for. This will allow a slightly larger engine mount box. The tank will be a 16 oz, should be plenty big for a gas engine. My US-41 will fly for 20 minutes on 16 oz, so I figure I can get 15 minute flights on a 50cc engine, more than enough.

redtail

My Feedback: (15)

Looking good, I fixed my Dawg so that I could bolt the floor panels in to get access to the receiver/batt if needed. You noted that you would construct hatches, wish I had fully thought that out like you did. I hope to put the receiver under the pilots seat and the batteries under the pilots feet. The rudder/elevator servos are behind the observer. My engine box bolts to the angle pieces you installed. Had to add to the length to get the back plate to extend just outside the engine cowl. The cowl looks nice and clean without the mounting bolts hanging out. Glad I caught that and could pass it on. Chic

khodges

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I decided not to make any exterior hatches for servo or electronics access. Once they're in place, how often do you really need to get to them? I didn't think it was worth going to the trouble, or having something to detract from the finish. With the cabin "roof" taken off, there's not much you can't get to in this plane, unless it's halfway down the tail.

I'm waiting to build the engine box until I decide once and for all what I plan to stick on the front for power. I like the thoughts of that 50cc twin, but haven't seen one in "person" and would like to be able to test fit it. The ZDZ has reliability and power going for it, but I just can't get around having about 1/2" of the spark plug cap sticking out the bottom of the cowl. I don't know why it's such a big deal, except that I'm going to all the effort to make it as scale as possible. What do you think, out there? I have a US-41 on another plane, same size as the Quadra 40. It's a good engine (but impossible to flip start), will fit inside the cowl, but I think a 22" prop is a bit much for it. I'm using a 20-6 with it now and it is okay, but I think I'd lose another 500-600 rpm at least, and I turn about 7000 now.

redtail

My Feedback: (15)

Well, here goes. I am attempting to find the pictures I want to show you that are hidden somewhere on this computer. These pictures range from the removal of the cowl mounting bolts, prior to sanding the microballoons, the hatches on the side of the cowl, the wheel covers, the color scheme, the step, fake air inlet, and the project I'm about finished with the SR9, British Lend-Lease Stinson with Field Marshall Monty. General Ike flew in a make-shift back seat in a P-51B to observe D-Day, Monty tried not to be outdone. At least he had the British roundels on an American aircraft. . I think I have covered the photos. Now to get the photos to post. Here goes.

redtail

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Lights, camera, and action:

redtail

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Roll camera:

redtail

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The cowling has been cut and reglued inside to simulate a nonfitting, typical cowl panel and latchs. I opened the rear, front, and bottom edges. It seemed to match 90% of the photos I have seen of the latched cowl halves. I used Vailley wheels and made the covers from 1/16 ply and used sheet metal button head screws to hold them on. Will paint later. The door outline is scored into the fuse side panels. I used three points to internally mount the cowl with L brackets. Chic

khodges

My Feedback: (1)

Looks good, Chic. Have you considered making the door fully functional? roy said in his e-mail that ots of builders do it and there's no compromise in structural integrity; he did recommend putting doublers on all the formers, though. I discovered another departure from scale on this plane, but it is structural and not shape or appearance. If you note the slope of former #3, in location and relative to the front edge of the door and window, there is a fair amount more in the model. The fuse box beam on the full scale follows the forward door edge line, directly to the landing gear instead of forward of the gear as in the model. I'm sure this departure is for ease of construction and fewer pieces. It isn't noticeable, unless you plan on making a functional door. I plan to add a small "faux" former down the door edge and blending it into the real one at the bottom of the door window., and duplicating on the left side as well.

I didn't do much this evening except mess with the cowl and start sheeting the top of the fuse forward of the windshield, as well as the block on the underside at the firewall.

I was going to post a pic of the former at the door on the full scale, but can't find it on the 'puter. I have a print; I'll take a picture of the picture and post it later.

redtail

My Feedback: (15)

Ken, if I had been such a great planner, such as how you have been engineering this build, I may have decided to make the door functional. I have learned alot from this build and the TF Stinson that I highly modified to make the military version of the Stinson Reliant that hopefully I will take with me into my next two projects, the Meister P-47 Razorback and the Charles Kellogg TBM Avenger. We can only pray that we learn from our mistakes, God knows that I have made them. Need to go get some wood sealer and waterbased polyurthene to start glassing the wings with tonight. Chic

khodges

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Here's what I was talking about with the #3 former. The full-scale's box former is more vertical and comes a bit closer to the door than the model. It does this because the bottom of the former on the full scale is the landing gear and wing strut mounting points, a major structural load point; the top of the former is the main spar area for the wings. The entire BirdDog structure centers on this former in the full scale. Thompson's book talks about how simple maintenance was on this bird; the landing gear only had ONE bolt for each leg, and the wings could be replaced in less than an hour. All the crash and ground loop pictures I've seen of this plane show a pretty much undamaged area around this former, regardless of how bad the remainder of the plane was.

Sorry about the dust on the pic; too much sanding, not enough vacuuming

khodges

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Skinned the top and bottom of the boot cowl area today; took a bit different direction from the plans. They call for a balsa block on the bottom, flanked by two pieces of 1/8" on each side, carved and sanded to shape. I used the large block, per the plans, but then cut a couple of thinner blocks for the sides and carved them rather than trying to bend 1/8" pieces. This left them a bit shy of sitting over the former, instead they fit between. So I sheeted the whole thing with 1/32" hobby ply over the blocks. Hard as a rock and smooth as glass now.

For the top of the boot cowl, I sheeted the area with 1/16" balsa and then sheeted over that with 1/32" hobby ply. Of course, it's 1/32" thinner than using 1/8" balsa like the plans, but I figure that much will get sanded off the balsa to smooth it; the ply is almost ready to finish as is, and is much stiffer and stronger.

For kicks and grins, I put the cowl in place, and taped the windshield brace where it goes, to get an idea of the relationships. I won't actually make the fittings for the cowl until the engine is mounted, so I can match the center hole to the prop shaft. The windshield brace is made from 1/4" ply, cut 1/4" wide (1/4 x 1/4) and is much too big. I'll find a piece of 1/4" wide by 1/16" aluminum or steel and make another brace to replace the wooden one. This fits inside the windshield, and another strip will go over it on the outside, with a small grab handle at the base (see full-size pic)