RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
Here's a full-size PDF of the instructions.
Posted on: 8/25/2012 9:37 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11206128

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
Here's a vid from YouTube.. looks like the same size.
Posted on: 7/28/2012 5:04 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11172601

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
No wonder I was confused looking at your photos! I was wondering how that could be the same model. Should have read your earlier description more carefully, but regardless appreciate your help and am taking your advice on cockpit area strength seriously. I'm heartened to see that the support within the canopy bubble (pic below) looks good because I'm going to have to make one to provide support on mine.
Posted on: 7/22/2012 5:18 AM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11164274

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
I think you might have trimmed your canopy too much and that's why you had problems fitting it. If you look at some of the real T-28 photos above, you'll see how the bottom of the canopy extends down quite a bit - it's especially noticeably when the canopy is open, less so when it's closed because the painted metal bottom blends with the fuselage quite well. It's a lot different from the Bearcat and Corsair I built where the canopy is trimmed tight and rides the top of the fuse. It looks like you must have extended the fuse skin upwards an inch and a bit. But I think the painted result will look the same. +++++++ I finished skinning the fuselage and gave it a rough sanding. Also rough shaped and hollowed the rear canopy block and played with the canopy position some more. Masking the the clear areas (I masked the inside, but on second thought I think it should mask the outside and paint the outside is that correct?) made the structure more visible, and is giving me confidence that a canopy battery hatch is going to work. The center crutch and upper longeron run the length of the fuse and I don't see that having the canopy removeable is going to change the structure much from the original design. I'll be fiberglassing the plane to that'll add a lot of strength too. Next will be to trim the F6 canopy floor to fit in the higher position (upper longeron, vs the intended center crutch position), add canopy rails and start putting together the removeable canopy structure. I won't be doing much with the cockpit.
Posted on: 7/21/2012 8:23 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11164045

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
Hey Erez... seems like I didn't get an email when you posted (or for any of my other subscriptions for that matter) so I didn't notice your post. Your model is looking really good! I'd be really interested in seeing some detail shots of how your canopy looks - I'm still mulling over how to turn it into a battery hatch. Got some ideas but some pics of the real thing would be great. +++++ I've done a bit of work, not much with summer and flying. There's many long winter months coming when I'll be glad to have something to work on so there's no rush. I mentioned I was going to plank the fuse, but when I looked at the size and nice quality of the big side sheets I dropped that idea really quick. So I glued it on and only then realized that I'd forgotten to sand the stringers level with the formers. My build threads are a litany of mistakes - the purpose being to reinforce lessons learned I hope. Rather than pull the sheets off and redo them I added some thin 1/16 - 1/8 strips along the edge of the formers so that the upper and lower sheets have something to stick to when they're glued flush with the big center sheets. It puts the profile a little out but nobody is going to notice. I haven't finished the sheeting yet. I also cut square holes for the battery in the firewall and the first bulkhead. The holes are plenty big enough to accommodate any size 5S or 6S lipo, but the motor box is going to be pretty big to fit around it. The plan is to have room to push the battery through the firewall if it's needed for balance. Also finished installing the servos in the fuse as well as the nose gear mount on the firewall. I was pretty surprised when I was prepping the Bearcat to see the servos in the fuse rip the rails right off their connection to the formers, so I'll be adding some reinforcement on the Trojan servo rails. The Bearcat is now down with Lado retract issues - another month I guess for parts to arrive from France. Nothing but trouble with the Lados. Back on the Trojan, I followed Mike's suggestion and drilled 1/4" holes through the balsa block I was using as the horn mount on the flaps and ailerons and made a bit of a mess of it. The drill chewed through the thin sheeting and in a couple cases, ripped up the ribs a bit. I should have gone with a smaller hole but I had 1/4" dowel sitting around. In the end I used globs of resin mixed with microballons pushed through with the dowel pieces to fill any big gaps and hold everything in place. It looks a sight but after sanding it down it's hard to feel even a bump where the repair was done. I won't be noticeable after it's finished. Worth the effort for some peace of mind!
Posted on: 7/16/2012 9:13 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11158195

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
[quote]ORIGINAL: EF BTW, mine is painted yellow, for good visibility, but then I discovered there's an ARF of nearly the same size and color scheme and so now everyone will think I did not actually build it myself [&o] [/quote] Would love to see some photos of your model. I've been leaning towards yellow because it looks nice (especially with some detail added I think) and my field has lots of red and white T-28 foamies. Know exactly how you must feel! The instructions sheet of this kit cover doing the LE extensions with microballoons and even has a paper mold to cut out of the plans. I'm picking up some of the phenolic type of microballoons that DP recommends in his videos at a shop this afternoon - they were hard to find.
Posted on: 7/6/2012 11:25 AM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11145479

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
Now that's a warning I won't soon forget... well told and well received! Great solution too - many thanks. I'll post pics when it's done.
Posted on: 7/6/2012 11:09 AM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11145463

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
I took a break to stew over a few things that have been bothering me and of course to get in a lot more hours of flying time. -1- long fuselage Using either the 3-view included on the DP plan, or the Squadron/Signal 3-view, I figure i need to cut 12.5cm (~5") off the fuselage to get a match. But then the wingspan becomes a problem. the T-28B has measurements length 32'11", wingspan 40'7" for a ratio of 0.811. Measuring directly off the DP plans, the ratio is 0.808 for a difference of 0.003 which is negligible. So the model has the correct length/wingspan ratio which indicates that the wingspan is as much out of scale as the fuse is. I'm not sure that makes sense, but it seems that shortening the fuselage wouldn't solve the scale problem. It doesn't help that every photo of a full-scale T-28 seems to have slightly different fuse/canopy/cowl proportions from then next photo. Same with photos of the DP model sometimes they look fine, sometimes strange. I attached some pics of someone's DP model that look pretty good. -2- canopy height Texas correctly pointed out that the model's canopy has a lower profile than both the original T-28A canopy and the low profile canopy that was introduced later in the A-version production (ref. Squadron book). I've sent an email to Black Horse asking if they stock canopies for the .61 (65") ARF that they no longer appear to produce. Not holding my breath. -3- battery access I appreciate airraptor's ideas on battery access but when I'm flying I don't want to take the plane apart (either the wing or the prop/cowl/motor) just to change a battery. The BH ARF design has the entire canopy pull off - it looks ok and I'll go that route. The 65" one-piece wing is as large as I can transport and I don't want any more field assembly than that. -4- prop size and motor selection The BH T-28 ARF is the same wingspan but uses a 14" prop, whereas the DP model can accomodate a 12" max (13" would be asking for ground strikes or lawn mowing, even if the front wheel was brought from the 2" specified, to 2.5"). This was really frustrating as a 14" prop opens up a whole new world of motor/lipo choices (BH recommends a Rimfire .80). In the end I ordered the Scorpion S-4020-8. I have both 5S 5Ah and 6S 5Ah lipos and a CC 75A lite ESC available already. Switching to glow or gas just isn't in my plans now. -5- finishing method I spent the last few weeks watching the DP Bulding and Fiberglassing, and Detailing and Painting videos and have decided to take the plunge and try my first fiberglass job with Klass Kote paint. It's not hard to look at the TF Corsair and Bearcat I built and realize how much better they could look if they hadn't been done in Ultracote. If it flies well I might just redo the Bearcat - it's ready to test fly, I'm just working up the courage now. With the T-28 so much out of scale I'm leery of putting months of finishing work into it, but on the other hand, my first attemp isn't likely to impress anyone so... better sooner than later. Have been busy sourcing and ordering the K&B resin and Klass Kote paints that are recommended - not as easy as it should be with few if any suppliers in Canada and chemical shipping restrictions from the States. As far as color scheme goes, I think I'll stick with the red and white traditional T-28 colors. If I did it in yellow it would probably look like an old pattern flyer with Navy decals stuck on it! The grey and white looks good too but I think I'll go for markings that make it totally obvious what it is. With that off my chest I'll get back to building! Just for the experience, I think I'm going to plank the fuse instead of sheeting it.
Posted on: 7/6/2012 7:37 AM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11145195

RE: Cutting straight 90deg edges to make sheets
That's the method I was trying to remember skeeter - no sandpaper! The #11 carbon steel Swann-Morton scalpel blades and handle I got yesterday should cut like butter through two sheets at once. And now I can go ahead and cut the 1" sq tubing into 2" and 3" lengths to be filled with molten lead to serve as weights on my new 4'x7' 5/8" tempered glass bench top.
Posted on: 6/27/2012 5:14 AM by Author "ChinookRC" in the forum "Tips & Techniques"
http://www.rcuniverse.com/forum/fb.asp?m=11133569

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
I'm in a bind with the battery hatch. If the hatch is the length of the space between the firewall F1 and the next former F2, there is enough space to slide a 6S lipo down onto the hardwood motor mounts. It's a very tight fit. Since the best lipo position for balance isn't known yet I'll leave holes in both F1 and F2 so the battery can slide in either direction quite a bit. The problem is that the canopy is in two parts, with the front windshield piece sitting on top of what would be the top of the battery hatch (F1 to F2). At this moment I'm not confident that the gap between the windshield and the canopy could be held tight during flight, but it's possible that some well placed magnets along F21 and F20 could do the job. Any gap at all could force air under the canopy and will eventually rip it away in flight. The other option, similar to what I see at the field on foamies and Extra/Edge designs is to have the entire windshield and canopy pull off leaving a huge access hole at the top of the fuse. But this canopy isn't like the the Corsair or Bearcat where it's just a bubble sitting on top of the fuse the T-28 canopy plastic extends well down the fuse sides all the way to the first stringer above the center crutch. It connects to a 1/8" sq canopy support that is glued to this 1/4" sq stringer. I could upsize the canopy support and use magnets between it and the stringer, probably with some cross spars to hold the shape width-wise between those canopy supports. At the front the hatch would separate just behind the firewall, and at the back behind the angled F19 piece that rests against shaped balsa blocks that form the transition between canopy and tail. The second is becoming my preferred option, but this is where it's unfortunate that the canopy is somewhat warped and will likely need a wire support glued inside beneath the painted center canopy frame. Not too bad. I wouldn't build the C1/2/3/4 instrument panel box, nor do any other cockpit detailing, which I wasn't planning to do anyway, this being a flying machine for me and not a true scale model.
Posted on: 6/23/2012 6:47 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11129240

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
Hey Airraptor in the end I decided to trust the designer and didn't adjust the tail former spacing to reduce the length. But my suspicion is that it was simply fashionable at the time to make a warbird look like a pattern ship (the T-28B being a perfect candidate for that) and that it would fly just fine with about 1.5 inches removed. Then again, I have no way to confirm that so you could be the one to try! Too bad Dave didn't answer the question when I asked him.
Posted on: 6/23/2012 5:48 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11129186

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
The thin Mercury is probably from August 2011 (first opened) and really doesn't seem to work very well. Could it go bad that quickly? The medium is brand new and no complaints.
Posted on: 6/23/2012 5:43 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11129176

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
I put the wing away and glued the fuse formers, stringers and longerons together in a couple hours this evening. There's a 2deg downward thrust angle built into the firewall. I received the DP videos I ordered and have been watching the Building and Fiberglassing series.. really informative. I'm kind of mystified at how he uses thin Zap CA for almost everything it seems. He puts pieces together, dabs a bit on and that's it. He does mention quite often that he's just tacking the pieces and will go back later to do a proper gluing job, but he doesn't show how he does that! Thin CA again? I tried this with thin Mercury CA and the pieces didn't hold so I went back to applying mediun CA to one of the pieces and joining and holding them in place for 30sec to a minute. Makes me wonder if I should pick up some thin Zap, or just continue doing what I'm doing.
Posted on: 6/22/2012 10:22 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11128484

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
The flaps and ailerons were cut into their respective pieces and I marked off the hinge locations on the wing TE with push pins, then pressed the F/As against the pin heads to mark the positions. Must be a better way to do this. Cut slits for the CA hinges. The flap hinges are at the bottom of the TE, which was different from the Corsair and Bearcat. Realized I'd forgotten to install the horn support ply inside the F/A structures so I put in small balsa blocks and screwed in the stock horns temporarily for fitting the control rods. Seemed to work ok. I dripped some thin CA in the screw holes to harden them and will epoxy them and the horns after covering. I wasn't too happy with my choice of threaded control rods exiting the wing skin (except one, which needed a z-bend and a bend to make it over the cross-wise rod at the bell crank). The metal Sullivan clevises were impossible to screw on so I switched to nylon which were much easier. Took a long time to get the surfaces lined up with balanced throws on each side. The CA hinges won't be glued until after covering so it's hard to tell right now how much accurate it is. Filled in the most obvious dings and dents and have set the wing aside for now. The tip blocks will be added just before covering to avoid hanger rash.
Posted on: 6/17/2012 8:22 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11121891

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
I got a little frustrated this week sheeting the wing and haven't been posting, but in the meantime I did manage to finish the wing: Drilled out the fixed LG key block and cut slots in the bottom of the wing. One of the wire LG needs to be adjusted to fit the angle. For some reason it didn't occur to me to use the water spray bottle sitting on my table until I got to the last wing panel, and then the edges finally clamped down tight to the LE and TE. The other top panel doesn't look very good and I was po'd. It's structurally sound though and some balsa filler covered up the thin gap at the LE. There isn't a section view of the wing where the servos are installed so I couldn't plan ahead for having my servo arms sticking up above the top sheet. No way to tell at this time if it's going to be a problem but I went ahead and cut out access holes. These will be inside the fuse and should serve for maintenance. Building in washout meants that the TEs had an upward curve which complicated building the flap/aileron pieces. I decided to pin the F/A LE to the wing TE, following the curve, and then I glued the lower F/A skin in place while still pinned to the wing. The ribs were CAd in place also. The result was pretty good - the F/A piece held the same curve as the wing TE.
Posted on: 6/17/2012 8:02 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11121868

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
Looks like the Power 25 is rated for 3-5.5lb planes and this will come in at 7.5lb, probably higher with the 5S or 6S Lipo. The 12-inch prop limitation means I need a big motor with high Kv and there aren't that many out there. The Power 60 is 400 Kv. This wasn't an issue I was aware of initially so this has been a good hands on intro to sizing electrics. Another lesson today was to not use pins with little round heads - they leave little round dents and the heads pull off! Sheeted the bottom of the wing and epoxied the fixed LG key blocks. Made a 4-foot aluminum sanding bar to help make straight 90deg sheet edges, something I've been having problems with. I've had the decals under one of my building boards for a week and they're still warped but otherwise in good shape. I really like the detailed placement guides Dave provides for all those little "hoist" etc decals. I've been guessing where to put them until now.
Posted on: 6/10/2012 9:41 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11113976

RE: Cutting straight 90deg edges to make sheets
Thanks a lot for the help guys. This is one of those topics that I could google all day and not find an answer to. After an excessive balsa dust in the home fiasco this weekend (sigh) I was hoping for a solution that didn't involve sandpaper but I picked up a 4-foot 1-inch square aluminum tube, spray tacked some 150 grit paper on one side, clamped it to my bench and used some smooth foam board to raise the balsa a bit and make it easier to slide back and forth. Works perfect and stores away nicely. The only improvement would be to build a grip to hold the balsa down firmly as documented in the airfieldmodels link above. Gap-free sheeting finally. Thanks again!
Posted on: 6/10/2012 9:17 PM by Author "ChinookRC" in the forum "Tips & Techniques"
http://www.rcuniverse.com/forum/fb.asp?m=11113959

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
Hey Texas.. I ran into one of your T-28 pics by chance in another thread. Great covering job! Can definitely see the pattern ship influence from this angle. I wonder how it would fly if I took an inch or two out of the tail between the canopy and the fin extension whatever that piece is called...
Posted on: 6/10/2012 11:31 AM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11113352

Cutting straight 90deg edges to make sheets
I'm looking for a way to trim plank sheets so they match up well when glueing them edge to edge to make wing or fuse sheets. If I use a straight edge to trim each edge the blade will often tilt and I don't get a 90deg edge. Depending on the grain, the blade sometimes rips the wood away from the straight edge. If I stack two sheets this problem is even worse. A balsa stripper will give me a 90deg edge but the edge needs to be straight, and I want the two edges to match. I'm sure there's a clever way to do this, but I'm not clever enough to think of it.
Posted on: 6/10/2012 11:16 AM by Author "ChinookRC" in the forum "Tips & Techniques"
http://www.rcuniverse.com/forum/fb.asp?m=11113339

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
In the end I didn't go with the swivel ball links because cost - at $4 a pair it would have been better to buy two more S3004 servos to co-locate in the wing space - binding would have been a problem because the linkages are all located close to ribs and the holes the rods pass through would have had to be enlarged considerably to accomodate the relatively hefty ball links passing through. So as I stick-built the rods I ended up with quite a hodge-podge of z-bends, l-bends, nylon retainers, metal clevises, copper wire wrapped joints, threaded and unthreaded 2-56 rods. The pins all fit very snugly though and the only slop I can detect is in the flap linkage where the geometry is causing some flexing of the rod at the ends of throws. I expect the needed flap throw will be much less than the max so this flexing shouldn't be an operating issue. The aileron links are rock solid and the rod/arm geometry is straight with no unusual stress on the servo. All said and done though, I'll be avoiding bell crank mechanisms in the future! This was good for experience, but it's pretty obvious that putting individual servos in place with short straight rods to the horns is faster and much easier to adjust and repair. I'll come to regret this, but at least I've done it once. Time to move on and sheet the bottom.
Posted on: 6/10/2012 8:22 AM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11113184

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
Appreciate all the advice guys - learn something new everyday. I'll go with the swivel ball link as recommended. I hate messing around with the ball and socket type and yes, the pin is often loose inside the servo arm hole. Hopefully will find the links and servos in stock at one of the shops nearby tomorrow. I'm looking at a 790Kv Scorpion S-4020-8. Running it through the calculator at 6S on a 12x6 gives it unlimited vertical, hover capability, and pulls 90A for almost 2000W in. I get the feeling that this could cause the fastest crash of a T-28 ever. Kind of steep at $160 but haven't looked around. I suppose I should start tame and work up. After building two boring blue warbirds I'm looking forward to choosing a color scheme. The white and red is too common at my field (foamies), the grey is nice but maybe a bit too monotone like the blue I've been doing. Lots of time to think about this.
Posted on: 6/9/2012 12:24 AM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11112033

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
The prop size limitation of 12 inches is giving me some grief selecting an electric motor. Using the WebOCalc online calculator it appears that I need something 600-700Kv, 40 to 50A on 5S or 6S. I have a 670Kv Turnigy G46 sitting around that gives me the attached specs, which are pretty much as good as anything else I'm finding on HK. The similarly sized 700 Kv rated Turnigy L5055C-700 gives slightly better power output, but I'm not sure it would be worth buying another motor. The 800Kv Rimfire 46 might be the best choice but it's $100. Have no idea at this point whether a 5S or 6S will provide better balance. I'm pretty sure the battery mount will extend through the firewall into the motor box to bring it forward enough. Appreciate any ideas.
Posted on: 6/7/2012 10:05 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11110835

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
Thanks - I'll drop by the LHS this week and pick up the ball links (I see now that they'll offer more degrees of freedom than the e/z connectors) and some servos so I can start sheeting the wings. I superimposed traces of the model side view and the 3-view that is included on the plans and the model is definitely quite a bit longer in the tail than the 3-view. The nose is also more narrow to give an overall more streamlined shape. And this is fine with me - I'm not looking for scale accuracy so much as a nice flyer that I can graduate to from my Nexstar trainer.
Posted on: 6/7/2012 5:20 AM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11109801

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
Mike.. would you recommend ball links over the e/z connectors? I suppose the latter with the set screw has a greater risk of something going wrong. The stock and Dubro bell cranks both have brass sleeves but I'll look around to see what the heli guys have - bearings sound like a good idea. There's an ongoing thread covering the DP 1/5 scale kit where I saw specs for the real thing showing 3 degrees of washout. We'll see how it turns out on this model. Thanks for pointing out the potential that I'm using an incorrect 3-view... if you have something more definitive for the T-28B I'd appreciate a copy. I'll take some time to trace the outlines in Autocad and overlay the results. The attachment here is a snap of the 3-view included on the plans, I'm guessing it should be correct. +++ Finished the right half of the wing and glued up the wing planks.
Posted on: 6/5/2012 10:28 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11108237

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
I sent in an order for some of the Dave Platt how-to videos and when Dave himself replied, I asked him about the date of the kit (he said 1973, before it went to Pica who 'cheapened' the quality) and about the longer than scale tail (no comment from Dave). The left half of the wing structure is complete after trimming off the excess spar, LE and TE length. The LE is straight while the TE has a noticeable curve up toward the tip because of the washout shims. I used the same washout jig w/shims on the right half. LE and TE to be glued in place tomorrow.
Posted on: 6/4/2012 9:10 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11106813

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
I finally got a chance to build washout into a wing. There's no mention of washout in the Platt documentation, and I can't find any recommendations on whether this particular model needs it or not, but I couldn't resist the opportunity to go ahead and build it in. Following the excellent article on washout attached (from AMA I think, but I can't find a link) I brushed up on my trig and calculated the TE lift needed at the tip rib W11 to induce 2 degrees of washout (~5mm). The wing root has a positive angle of incidence of 4.5 degrees and the choice of 2 degrees was arbitrary. The plans show a 1/4"x1/4" jig running below the aft portion of the ribs so I added a small 5mm block at W11, with 3 more blocks of descending sizes under W10, W9, and W8 to give a gradual twist out toward the tip. It looks like it should work pretty well. On the Corsair and Bearcat I didn't follow plans for bell cranks on the flaps and ailerons and used four co-located servos instead, but on this model I'll stick with the plan. So I glued in the bell crank platforms and servo rails, CA'd the ribs to the bottom spar, CA'd the top spar in place and added epoxy fillets. I considered adding spar webbing but decided to continue the weight saving philosophy and to follow the plan. Expected weight is only 7.5lb so it should be plenty strong as is. The low weight and the low height of the prop hub compared to a tail dragger also got me looking at the recommended prop size - 11x7, 11x8, 12x6 - and the realization that an AXI 4130 and 16x8x3 just won't work. So I'll have to look into more modest motor options. I'm starting to feel confident that this plane is a good choice for my flying skills. Checked the hardware bits and they're in great condition. I need to research the best hardware to use for a slop-free bell crank setup though.
Posted on: 6/2/2012 11:03 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11104402

RE: Dave Platt T-28B Trojan 1/7 Scale 65-inch
I'm not sure about the other T-28's designed by Platt but this one is far from scale, eschewing the stubby nose and short tail for what I can only guess is a more forgiving long tail and a slightly longer nose, perhaps for balance. If anything, it looks more like a pattern ship than a T-28 but it's certainly recognizable as a T-28. And that's fine with me - I'm more interested in easy flying characteristics than in scale accuracy, especially since it seems I tend to lose patience with the finishing work at the end of a build. The build starts a lot different that I'm used to, starting in the middle of the wing with the center W1 rib and working out on the left side to W11. No spending a week or two putting together fin, rudder, stab and elevators wondering if it'll ever start taking shape. After one evening half the wing has been put together. I thought I'd have a few weeks to shop around for alternative servos to the cheap and reliable Futaba S3004's I've been using but with this sequence I'm going to be shopping for S3004's next week. epoxied rib doublers as needed CA'd the bottom spars to the dihedral joiner. Not too happy that this key part is balsa. CA'd the fore and aft halves of the center W1s to the dihedral joiner (7.5 degrees) pinned down the left spar with the right half up in the air at a 15 degree angle the rib notches fit nice and tight around the spar for the dry fit
Posted on: 6/2/2012 10:35 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11104393

Dave Platt T-28B Trojan 1/7 Scale 65-inch
After completing a Top Flite Corsair and a TF Bearcat this past winter and realizing that it would be some time before I had enough experience to feel confident enough to fly them I started looking around for another warbird kit that would have flight characteristics more suited to a novice flyer. I wanted a 60-size plane that I could convert to electric and use my existing AXI 4130 motors, CC 100A ESCs and 6S Lipos. To further cut down on costs I wanted something that wouldn't look strange without retracts. The T-28 seemed like a good candidate and when a Dave Platt kit went up for sale locally, I grabbed it for $200. There's no date on the box or plans but looking at the bio on Dave's website I'm assuming that the kit dates between 1972 when he started the company, to 1975 when he sold it to the no longer extant PICO as there is no reference to PICO anywhere on the packaging. I wish I could say I've aged as well as this similarly dated kit! The contents appear to have remained in the box all this time and the wood is in perfect shape with no warping and only one cracked plank. The 3-piece cowl looks good and the trike LG isn't rusted. The canopy has been warped somewhat along one bottom edge but I expect that it won't be noticeable once it's glued on. The water slide decal sheets need to be flattened out but are otherwise ok and the plans are in perfect condition. The only complaint I have is that the main plan is split into two sheets and I haven't figured out how to join the scanned PDFs so I can print them out as one sheet at work. For a new builder like myself the instructions are minimal, even more sparse than the 1979 TF Bearcat I recently built. I don't expect there are a lot of these 40 year old kits out there waiting to be built, and I haven't been able to find a build thread anywhere so it looks like this will be the first and probably last 65" Dave Platt T-28 build thread. But I thought the same when building the '79 Bearcat and was surprised when quite a few people came out the woodwork with kits just finished or in progress and posted lots of help and encouragement on the build thread. I hope the same happens with this DP T-28! It's summer with vacations, long weekends, flying time and laziness in general so the build will be leisurely. The plan is to have it in the air this season, which means before the end of October or five months. Here are some photos of the kit. The scans I have of the plans are too large to post so just send me a message if you'd like me to email them to you.
Posted on: 6/2/2012 9:52 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11104059

RE: Top Flite F8F-2 Bearcat Red Box Build
I think I paid $200 (plus shipping) for mine also. Considering the price of current TF kits I didn't think it was too bad. Even the decals were still good after up to 30 years.
Posted on: 4/7/2012 9:01 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11032499

RE: Top Flite F8F-2 Bearcat Red Box Build
Looks great Stewpot and congrats on getting it done! Great motivation for me to get through the final slog of finishing it up. Wish I had the skills to make it look as good as yours! Sad to hear about the loss of a great pilot. He looks great flying the cat in this Reno race.
Posted on: 4/6/2012 10:25 PM by Author "ChinookRC" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=11031503