Peter Miller Posted January 24, 2019 Share Posted January 24, 2019 I love the odd ball aircraft. Recently I found this video on You Tube showing Frad Knapp's Li'l Cub breaking the Worl Stol record in Valdez, Alaska. **LINK** Here is a still just to tempt you I just had to build it. Model is going to be 54" Span for electric power Plans drawn. Building has started. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted January 24, 2019 Author Share Posted January 24, 2019 I spent a lot of time working out the best way to build it. The cabin sides are 1/32" ply on the outside with an inner lamination of 3/32 balsa. THis is so I can make good round grooves to take the balsa dowel for the rear fuselage. Stucture. Lightness is vital. Electric power is the only way togo with this model because pacticing STOL will almost certainly result in nose overs, Starting an engine a dozen time flight is not fun. The first step is to make the joint between the dowel and side. This needs a half round groove. Fortunately I have a 1/4" Abrafile but a good 1/4" round file will do or you can gouge it out with a sharpened 1/4" sharpened brass tube Edited By Peter Miller on 24/01/2019 16:08:51 Quote Link to comment Share on other sites More sharing options...
Nigel R Posted January 24, 2019 Share Posted January 24, 2019 That is certainly short! A lot of slats, some big flaps, and looks like every bit has been lightened as much as feasible. What AUW are you aiming at? I would think at 54" you need to be down in the 2lb - 2-1/2lb region? Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted January 24, 2019 Author Share Posted January 24, 2019 Yes, Hoping to be in the 2 lb area. Well those 1/4" balsa dowels only weigh 7 grams each!! Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 24, 2019 Share Posted January 24, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted January 24, 2019 Share Posted January 24, 2019 eyes down here as well peter...... ken anderson....ne...1.peter miller dept. Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 24, 2019 Share Posted January 24, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted January 25, 2019 Author Share Posted January 25, 2019 Well another bit further. Buildong thye sides over the plan. Because the sheet parts are on the side of the tubular parts I had a mirror image printed off so I can build both at once. Also tryingto build the second side over the first would have been tricky with round member this was a good idea. Here the longerons have been glued into the grooves in the sides. Shaping the joints is a lot harder with round stock. Not only do you have to get the angles right, the hollows have to be at the same angle The side has been built. The vertical member at the tail end is not fitted because when they are joined the fin post will go down and form that member. Not sure if I should make that out of birch dowel in case the fin gets knocked but then hinging might be a bit of a problem. We shall see My drawing shows the diagonals as being 3/16" however I found that the joints would have been much weaker so kept them the same as the longerons Edited By Peter Miller on 25/01/2019 08:27:34 Edited By Peter Miller on 25/01/2019 08:28:07 Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted January 25, 2019 Share Posted January 25, 2019 Brilliant Peter, just what I want but at about twice the size with carbon tube for fuse. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted January 25, 2019 Author Share Posted January 25, 2019 Well You can always enlarge my plans. There is some curvature on the plan view. Not sure how well carbon fibre tube will do that. Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 25, 2019 Share Posted January 25, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted January 25, 2019 Author Share Posted January 25, 2019 I am using the scale Piper Cup section USA35B but with the bottom flat instead of very slight undercamber. At the size I am building it the undercamber is barely visible. I am not using the slotted flaps. In fact the flaps are acurally curved down and I am making them flat like the ailerons. Just for added interest. I found this You Tube video of a walk round which shows some morfe detail in close up. https://www.youtube.com/watch?v=UZLH_2tMoGo&t=88s I am also simplifying the tail mounting and have reduced the extreme longitudinal dihedral. Edited By Peter Miller on 25/01/2019 11:16:51 Quote Link to comment Share on other sites More sharing options...
Nigel R Posted January 25, 2019 Share Posted January 25, 2019 Looks almost identical to the infamous Clark Y. Are you putting LE slats on? Thinking about wing loading, the full size Cub is 7:1 aspect ratio, I think. At 54" that's looking like 400 (ish) sq in, giving a loading of around 12oz / sq ft with a 2lb AUW, which certainly works for a slow flyer. At 2-1/2lb, it's14oz /sq ft. WCL for both AUWs is 6 and 7.6. A slightly challenging weight target with a wood build at this size I think, but certainly not impossible. I got 3lb dead on with a 500sq in wing of 52" span, using all sheet construction. Lots of open framework would knock that down a good bit and lighter drivetrain and radio gear could be used. Speaking of which, what sort of batter / motor / servos are you using? Dave M What was your J60 AUW? Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 25, 2019 Share Posted January 25, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted January 25, 2019 Author Share Posted January 25, 2019 It is very similar to Clark Y. Yes, I am fitting slats. I used them on my scale Legrande Simon and they really worked.A pain to make but... As fpor the area, the Li'l Cub has had its wings cropped where the tip curvature starts.the model is in fact just under 1/6" scale so the chord is 9 1/2 " which will give it a bit more area Quote Link to comment Share on other sites More sharing options...
Martian Posted January 25, 2019 Share Posted January 25, 2019 Looks great I'm following Peter Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted January 25, 2019 Share Posted January 25, 2019 This is what I’ve really lusted after **LINK** Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted January 25, 2019 Author Share Posted January 25, 2019 Well not the same but it might be a lot cheaper to build Quote Link to comment Share on other sites More sharing options...
Nigel R Posted January 25, 2019 Share Posted January 25, 2019 Great stuff. More wing than I'd guessed. It'll work out quite close to daves j60 I should think. Wing loading that is. What are the slat going to be made from?Edited By Nigel R on 25/01/2019 19:01:07 Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted January 25, 2019 Author Share Posted January 25, 2019 The slats will be laminated from 1/32 and 1/16" sheet balsa. On the Legrande Simon I shaped a piece of hardwood to lamintae them, This time I ma just use the wing leading edge if I can't find the old pattern Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted January 27, 2019 Author Share Posted January 27, 2019 More progress. The fuselage is basically assembled. It pnly weighs 8 ounces. The rear end has a bit more sheet thanthe original to support the snakes and the rudder post and leading edge Front view shows shows the formers. Possibly the could be one less but the rear three are liteply and have very large lightening holes. The wing is very simple. Here the lower LE sheet and rear spar capstrips are laid down. The flaps are fully sheeted The centfre sectuon is being buit as well/ The ribs and top spar have now been added. Note the tip rib. The full size aircraft has the ends of gthe wings left open so I have fretted out the tip rib in liteply. Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 27, 2019 Share Posted January 27, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted February 3, 2019 Author Share Posted February 3, 2019 Things have moved on. Got a lot more building done. The trouble is that I have to set my "studio" up so I wait untilI have done quite a lot. The wings have now had their leading edge sheet and all the capstrips done etc. This shot also shows the slats being made. 2 laminations of 1/32" sheet and two of 1/16 sheet. glue is applied and then they are taped very firmly to the leading edge and left to dry. This is one of the servo mounts and its location in the wing. Note also paper tubes. The two wings and centre section ready for joining. This shot shows the laminations of the slat. Hold down nuts and tail mounting have been added. also the 1/64" ply over the instrument panel The servo mounts for the rudder and elevator. They are buried rather deeply in the fuselage. The fin and rudder are very light. The fin post is birch dowel just to take the loads of the model going onto its back. Hunge slots were cut with a fine cutting disc This is just a dry assembly. Not that the fin does not touch anywhere except for the leading edge and rear post. The sheet under the tail is to support the snakes The tailplane and elevators are similar on construction to the fin and rudder. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted February 3, 2019 Author Share Posted February 3, 2019 Forgot a couple of pictures The fretted out tip rib is a very distinctive feature. THis is my standard strut mount made using a metal clevis. I fit it to a short piece of threaded rpd and bind this to ply with wire. I ten solder it in place.Easy to use and not screws to lose on a cold day or in deep grass. Quote Link to comment Share on other sites More sharing options...
Tim C Posted February 3, 2019 Share Posted February 3, 2019 Totally bonkers plane, great innovation on the building techniques, hope it flies as well as it looks, is this destined for RCM&E any time soon? Quote Link to comment Share on other sites More sharing options...
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