Alec Turnbull Posted October 4, 2023 Share Posted October 4, 2023 A few months ago a chap in North Wales advertised on Facebook Marketplace a few years worth of RCM&E magazines for free if collected, so I went and got them. The other day while casually flipping through one of them, Sept 2016, I spotted an article and free plan for the Sleeker by David Ashby the son of the original designer Maurice. With nothing on the board at the mo it grabbed my attention, studying the plan I realised I have just about everything in stock to build it including a suitable brushless motor. In the article David describes using a 850mah lipo, thats a bit small to get any duration plus I do not have one so I have decided to use someting a bit bigger probably 1500 mah, of course that adds a bit of weight so I thought that extending the wingspan by one bay would bring the wingloading to somewhere sensible approx 2.5 inches either side so now it will be a Sleeker 37. A much smaller model than I am used to so it shouldn't take too long. So... I have set to cutting out some cardboard templates Starting with fuselage as I will have to cut the plan up to join the wing drawing together, I want to get that bit right first. Apart from extending the wings I have slightly altered the design of the tail section of the fuselage, in his article David mentions that he had resited the horizontal stabilser on top of the fuselage to avoid damage as he as not going to fit any undercarriage, I will do the same, but he did not alter the tailplane incedence so rightly or wrongly I decided to redraw the parts to give a zero degree incedence that also meant a slight revision of the vertical stab and the rudder, I also smoothed out the lower rear of the fuselage to smooth out the contour. So thats all the fuselage bits all cut out ready to put together This is the motor I am going to use, the same size as the one in Davids model, a 2826 size outrunner Here is a brief view of Davids info packed article that grabbed my attention, I will get the fuselage all put together quickly then get on with re drawing the wing and getting that done. Quote Link to comment Share on other sites More sharing options...
Alec Turnbull Posted October 9, 2023 Author Share Posted October 9, 2023 Fuselage in the jig And back out again with upper and lower sheeting in place Before I joined the sides I fixed a couple of balsa rails to fix the servo tray in later, it would have been difficault to get my fat fingers in there once joined All done including a hatch for the lipo made out of 1/16th ply Yesterday I was allowed in the garage for a few mins and joined some sheets of 1/16 balsa to make up the wing skins, I use Gorilla glue for this task as it sands quite well. Quote Link to comment Share on other sites More sharing options...
Alec Turnbull Posted October 10, 2023 Author Share Posted October 10, 2023 The free plan that came with the magazine is printed in such a way that it has to be cut up to make a complete plan of the wing, since I am extending the wing a little to help with the extra weight of the intended lipo plus that the paper used for the free plan is a bit flimsy I have decided to redraw on some cartridge drawing paper, its is a simple design so no difficaulty there. The extension to one extra bay each side means 7 bays which divided into 36 inches gives a very odd dimension, so the easiest way (for me!) is to get the digital calipers out to use those to mark off the rib placement. There we are 2.5715 inches, my 72 year old eyes were never going to spot that on the ruler! All done, only took about 15 minutes , first time I have drawn any thing since TD lessons at school...... The (original) drawing says to use 1/4 square hard balsa for the leading edge, I imagine that was specified as there is no wing spar, however my balsa stock of 1/4 ,in my opinion, is not very hard, I also came to be aware that the size required is actually 3/8, which takes into allowance the wing skins, so what I decided to do was use a 1/8th strip of hardwood, glue it to the hardest 1/4 strip I could find, to obtain the correct size and provide a little reinforcment, glued to the lower face so that the eventual sanding of the rib profile will be easier. (Is that as clear as mud?) I used my favorite Gorrilla Glue for this, I was given this some time ago and have only just started to use it in place of the usual aliphatic, I find that it goes off quite quickly and sands well, any excess is easily wiped off with a wet rag. Next task is make up the wing ribs, there are not that many, so I made a template out of a piece of scrap ply, as a register to enable a repeatable result , drilled 2 1mm holes, inserted a cocktail stick so that the sharp end just protruded through, this would mean that the template would not slip from my buttery fingers whilst drawing round. Another benefit found was that after the ribs were cut out I could use the register holes to finally, lightly sand the rib edges one at a time to ensure accuracy, the change in the sound of my Permagrit sanding thingy changes as soon as it touches the ply so you know that you are there, I am sure I didn't dream up this method myself I must have seen it in a magazine somewhere years ago and filed it in the back of my head. Anyway the ribs are drawn onto the balsa sheets and ready to be cut out All done The end result reminded me of ( over sixty years ago!) of cutting out the parts of a Kiel Kraft Minimoa with my dad, thats where it all started........ 2 Quote Link to comment Share on other sites More sharing options...
Alec Turnbull Posted October 11, 2023 Author Share Posted October 11, 2023 Left hand wing panel laid down And right hand panel also I thought it best to join the two halves of the wing together before sheerting the top sides as it is possible to get a better grip for the clamps for an even adhesion Top skins on, end ribs on and a good sanding the wing will be finished 1 Quote Link to comment Share on other sites More sharing options...
Alec Turnbull Posted October 12, 2023 Author Share Posted October 12, 2023 Wing skinning under way and all done ready or covering 2 Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted October 12, 2023 Share Posted October 12, 2023 You're working well Alec. 👍 Quote Link to comment Share on other sites More sharing options...
stu knowles Posted October 13, 2023 Share Posted October 13, 2023 Dihedral Brace? 1 Quote Link to comment Share on other sites More sharing options...
Alec Turnbull Posted October 13, 2023 Author Share Posted October 13, 2023 1 hour ago, stu knowles said: Dihedral Brace? Good question.....none shown on the plan, however it is a small wing, the two central ribs are 1/4 balsa glued face to face and the resultant joint is very strong, I imagine that the original designer thought that is sufficient, rubber bands will be holding the wing down securely to the fuselage so I believe there will little or no movement or wing flexing in flight, now the wing sheeting is done the whole assembly is extremley rigid (as I expected it to be). All these things went through my mind before construction commenced, I decided that the designer knows best.........and me ? What do I know? Out of interest I have just weighed the model as it is including the motor and esc, it comes out at just on 12 ounces so once covered with two mini servos, that I am waiting for, I am antipating a total of about 1 pound all up but then plus the lipo, which I haven't decided on yet, so I don't think the flight loads will bee all that high, but we will see! Quote Link to comment Share on other sites More sharing options...
David Ashby - Moderator Posted October 13, 2023 Share Posted October 13, 2023 Excellent work Alec. Dad is still around (he's 91 now), so I'll show him your '37', he'll be very pleased. I still fly mine, the wing join did make me a little concerned but I needn't have been, it's perfectly fine for the task in hand. Looking forward to seeing yours complete and flying. Quote Link to comment Share on other sites More sharing options...
David Ashby - Moderator Posted October 13, 2023 Share Posted October 13, 2023 He did design a Sleeker 2, a little larger with a slimmer fuselage. It flew but he didn't pursue it so the plan wasn't published. Quote Link to comment Share on other sites More sharing options...
John T Posted October 13, 2023 Share Posted October 13, 2023 3 hours ago, stu knowles said: Dihedral Brace? Some of the large thermal soarers of the 1970's such as the Blue Beast (141" span) just had the outer wing panels butt glued without any bracing, and these could withstand quite high tow or bungee launch loads without failing. I think the reasoning was that an "arrival" would result in a clean break which could be quickly re glued rather than causing further damage where a dihedral brace was pulled out. Quote Link to comment Share on other sites More sharing options...
Alec Turnbull Posted November 7, 2023 Author Share Posted November 7, 2023 On 13/10/2023 at 08:45, David Ashby - Moderator said: Excellent work Alec. Dad is still around (he's 91 now), so I'll show him your '37', he'll be very pleased. I still fly mine, the wing join did make me a little concerned but I needn't have been, it's perfectly fine for the task in hand. Looking forward to seeing yours complete and flying. Thanks for that David, I have been a bit lazy lately but here it is finished and ready for its first flight. Weighs in at 1lb 7oz including a 1400mah lipo, on my Multiplex C of G balancer it comes out exactly 50mm back from the leading edge as yours did, so pleased with that as I did not want to add any more weight, but did not really expect to with the bigger lipo. So, another one done, thats four projects completed so far this year DB Centurion, GiGi, BigWig and the Sleeker a busy year of building, pity about the weather! 1 Quote Link to comment Share on other sites More sharing options...
David Ashby - Moderator Posted November 7, 2023 Share Posted November 7, 2023 Excellent, a very nice neat job Alec. What's next then? 🙂 Quote Link to comment Share on other sites More sharing options...
Alec Turnbull Posted November 7, 2023 Author Share Posted November 7, 2023 3 minutes ago, David Ashby - Moderator said: What's next then? 🙂 I have recently been diagnosed with a terminal disease (nostalgalitis) of which the main symptom is to go back in time and do things all over again! So the next project (if anyone else can remember it) is a Unicorn by Norman McFarland, my first low winger I had two of them in the day so if that wasn't enough I am going to have another. I have even bought a vintage 61 glow motor to go in it, an ancient HB61 which I got running just the other day.....there are no tablets for this malady, unfortunately! 1 Quote Link to comment Share on other sites More sharing options...
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