Timo Starkloff Posted April 19, 2016 Author Share Posted April 19, 2016 Fuselage is nearly finished. It took many small parts of Oracover and some hours patience, but all went well. The molding for the landing gear fairing is nearly finished, which means I can work further on the wing. Timo Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted April 19, 2016 Share Posted April 19, 2016 My that looks good, I like the colour as well John Quote Link to comment Share on other sites More sharing options...
Timo Starkloff Posted May 12, 2016 Author Share Posted May 12, 2016 Many details now to work on since the building comes (slowly) to an end. Timo Small pieces of plywood for mounting the servos. Moulding for the landing gear fairing finished. The markings are made from Oracover, fixed with tape and cut out with a sharp knife. Works quiet fine. Quote Link to comment Share on other sites More sharing options...
Timo Starkloff Posted May 14, 2016 Author Share Posted May 14, 2016 The wing is covered Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted May 14, 2016 Share Posted May 14, 2016 Looking very sporty, nice job with the covering Timo, not be long now John Quote Link to comment Share on other sites More sharing options...
McG 6969 Posted May 14, 2016 Share Posted May 14, 2016 Superb craftmansship, Timo. Really inspirational for a rookie like me. Keep on this superb job... Hakuna matata Chris BRU - BE / CTR Beauty Control Quote Link to comment Share on other sites More sharing options...
David Humphreys Posted May 15, 2016 Share Posted May 15, 2016 What a great project. Superb craftsmanship and I can only mirror others in saying that is is inspirational! Keep up the fantastic work. David Quote Link to comment Share on other sites More sharing options...
Timo Starkloff Posted May 15, 2016 Author Share Posted May 15, 2016 Thanks for the support, it's a great forum here with many interesting projects I use simple and cheap hinges for the control surfaces. They are easy to install, reliable and you're able to attach them without a gap (which prevents flutter). For the flap hinges I use wire-end sleeves. I put them in place, shorten them a bit, bend them with a Phillips screwdriver and finally flatten them with a flat screwdriver. First servo is in place. ... and the fuselage markings applied, which results in a completely different look. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted May 16, 2016 Share Posted May 16, 2016 You have done a wonderful job Timo, the model looks stunning! Can I ask where you get such small wire end sleeves. The smallest I can find are 1.3mm OD Cheers Danny Quote Link to comment Share on other sites More sharing options...
Timo Starkloff Posted May 25, 2016 Author Share Posted May 25, 2016 Hello Danny my wire end sleeves have 2mm diameter. Slightly bigger works too on another plane. All servos and the motor are installed and I started with the wiring. Greetings, Timo Quote Link to comment Share on other sites More sharing options...
Timo Starkloff Posted May 31, 2016 Author Share Posted May 31, 2016 I just cover the servos with foil. Keeps the weight low and is much quicker to "build" than the usual way with plywood covers. The wing cables are all installed and the connector in place. A bit further on the right than planned - I thought of the fuselage spars when designing the TK4, but not of the accumulator deck. And another quick check for the looks with the markings on top of the wing. The plane looks better and better but the work place gets more and more stuffed with all kind of things (you need so much different tools and materials when finishing a model). Quote Link to comment Share on other sites More sharing options...
Timo Starkloff Posted June 18, 2016 Author Share Posted June 18, 2016 I added the servo linkages. I use a 1.2mm steel rod, bend it with pliers, grind and solder one side and put a clevis on it, fixed with a M2 nut. I need a voltage regulator to bring the voltage from the 6S accumulator down to 12V. The two electronics on the left are the switches for the landing gear. Landing gear is installed provisional. I have to make a test if the wire diameter is sufficient. I also have to increase the space for the wheels a bit. Looked fine on the CAD but is a bit tight in reality. Quote Link to comment Share on other sites More sharing options...
Tim Tolhurst Posted June 18, 2016 Share Posted June 18, 2016 I can only echo what others have said on here, lovely model, and outstanding craftsmanship. Quote Link to comment Share on other sites More sharing options...
Timo Starkloff Posted June 24, 2016 Author Share Posted June 24, 2016 The first try on the airfield wasn't successful, since the landing gear wire was too weak and collapsed after some meters of rolling. I ordered 4mm wire and received the mechanic drilled for 3mm and 3 and 4mm wires. Thought I give the 3mm a try before increasing the hole diameter. But the plane looked great on the airfield. After changing the landing gear and refining some other things on this occasion, I'll make another attempt after our holidays. We're looking forward to three nice weeks in England. Beneath that, I've read the book from Alex Henshaw "Flight of the Mew Gull". He ins mentioning the TK4 several times, flew against it at the 1937 Kings Cup and also contains a photo of it. The book itself is well written and exciting to read with many interesting stories, details and races, especially the England - South Africa record flight, of course. A great pilot and something special because I've seen his Mew Gull and the Comet flying at Old Warden last year. Best regards, Timo Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted June 24, 2016 Share Posted June 24, 2016 Looks fantastic Timo, don't forget the video John Quote Link to comment Share on other sites More sharing options...
Timo Starkloff Posted July 31, 2016 Author Share Posted July 31, 2016 Good news But first something about the preparation before the first flight. I checked several things and made small changes in the setup: - I changed the center of gravity back to the calculated point, instead of 10mm forward as sometimes done for safety reasons. The further in the rear, the better for start and landing to prevent a noes over. - I programmed the function to mix flaps with elevator. - I changed the landing gear from 3 to 4mm. The new landing gear is one I had in my shop from another plane. It's a bit shorter and won't be retractable, but should be also easier to start and land for the first flights. - I checked the angles of wing and elevator. Elevator should be 0°, wing +0.5°. In reality it's about +0.3°. - I increased maximum elevator to keep the tail down. I also increased expo to 60%, since I thought that I need much elevator only on the ground, not in the air. - Remembering experience from previous planes: I have to hold full elevator for long time during the start and increase throttle slowly. Timo Quote Link to comment Share on other sites More sharing options...
Timo Starkloff Posted July 31, 2016 Author Share Posted July 31, 2016 Two years of planning finally resulted in a first and successful flight! Start was late in the evening when the air was calm. Some high speed taxi tests with wind from the side showed that I need much rudder to keep the plane on course. After a minute of little trimming and getting calm, the flight was more and more a real pleasure. It took only a bit of power to stay in the air, the plane felt very safe at low speed and the top speed was quiet fast and looked good. all reactions were very smooth. For landing I came in straight and perfect but was not sure if the touchdown would be too late, so I increased power to get around again. The TK4 then went into a slow curve to the left which I couldn't correct (not enough aileron). Because of the low height, the flight ended in the wheat field, but without any damage. This wasn't the satisfying end of a first flight, but sure helpful to be prepared for the next ones. So the list for the second flight will be much longer: - Slightly increase rudder. - Increase aileron much more. - Check controller settings if the motor cut off is slowly. - Check balance of spinner and propeller (to prevent vibrations). - Change motor mount to CfK (to prevent vibrations). - Decrease downward elevator when applying flaps. - Order different propellers for testing. - Apply motor and controller cooling. Actually the inlet is blocked since the cooling path isn't finished and it wasn't clear how much cooling is necessary. - Last but not least, change the landing gear to the original length after some further flights. The TK4 flies fine over a wide range of speed, has a really low drag and looks good in the air. But she has character, sureley because of the small vertical tail, big cowling and motor torque. The task will be, to make the plane suitable for everyday flying. And now some nice pictures of the first flight, made by Michael from our model club. No video this time, but sure for the next flights. Timo PS: During our holiday in England we had a short but nice visit with tea and cake to someone who made an apprenticeship in the fifties at the same de Havilland school which constructed the TK4. He and a colleage made a model of the TK4 after the original plans. He and his old friends and contacts weren't able to locate them, but it was nice to find out some more details about the plane. Edited By Timo Starkloff on 31/07/2016 20:05:29 Edited By Timo Starkloff on 31/07/2016 20:20:15 Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted July 31, 2016 Share Posted July 31, 2016 Congratulations Timo Quote Link to comment Share on other sites More sharing options...
Timo Starkloff Posted August 22, 2016 Author Share Posted August 22, 2016 Thanks I changed the motor mount from plywood covered with glass fibre to carbon fibre, checked the propeller balance and the vibrations are gone. Quote Link to comment Share on other sites More sharing options...
Timo Starkloff Posted August 22, 2016 Author Share Posted August 22, 2016 Some more pictures of the (nearly) finished plane with some cockpit details and the accumulator installation. A pilot is definitely missing. Quote Link to comment Share on other sites More sharing options...
Timo Starkloff Posted August 22, 2016 Author Share Posted August 22, 2016 After a long week of model flying and about 30 flights more on the TK4 there is much to tell and show. A longer run on the ground is required for a takeoff at higher speed, which helps for a steady climb. A shorter start at too low speed could lead to a few up and downs on the climb. Starts and landings were also possible with crosswind. Flying is fine and very stable. Reactions on all controls are very smooth. Rolls come slow and loops I'm still training. I'm not finished with all tests, but it clearly is a racer and not a aerobatic plane. But she performs a nice and steady knife-edge flight when making a low level pass. The speed ranges from very slow to a good top speed. Didn't tested spinning yet, but when making the TK4 very slow there is no tendency to tip to a side. And the sound of the electric motor on high revolution with the APC 12x8 E prop is suitable for a race plane. When increasing throttle, it's important to do this slowly, otherwise it leads to a slight nose down. On landing the TK4 comes in stable, depending on the wind with more or less flaps. On the last meters before touchdown some minor corrections have to be made sometimes, but rudder, elevator and aileron are working flawless for that case. There is no tendency to go on the nose, so I decided to keep the shorter landing gear legs. All in all the experiment for a small and light racing plane worked quiet fine. It looks exciting, even on the ground. With its characteristics it surely demands an experienced pilot. But with the big fuselage and stable flying it looks bigger than it is, looking different at every angle and it's great fun to make high speed passes at low height. We took a short movie, but until I got that one ready for publishing here are some more flying pictures. Timo Edited By Timo Starkloff on 22/08/2016 20:44:04 Edited By Timo Starkloff on 22/08/2016 20:44:35 Edited By Timo Starkloff on 22/08/2016 20:52:29 Edited By Timo Starkloff on 22/08/2016 21:01:45 Quote Link to comment Share on other sites More sharing options...
McG 6969 Posted August 22, 2016 Share Posted August 22, 2016 In one exclamation... just 'superb', Timo. I don't really have much to add in words... except that it really needs a PIC at the stick... Gratulation & hakuna matata Chris BRU - BE / CTR Pilot Control Edited By McG 6969 on 22/08/2016 21:07:19 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted August 22, 2016 Share Posted August 22, 2016 Looks truly wonderful, well done Quote Link to comment Share on other sites More sharing options...
Timo Starkloff Posted September 25, 2016 Author Share Posted September 25, 2016 Still no pilot on board and I also haven't cut the video. But since August we have great and constant sunny weather with good temperatures. So it's better going outside for flying, the winter is coming soon enough. But I have some facts about the model. The speed is measured with 157 km/h, with which I'm really satisfied. It looks suitable for the size. Not too fast but definitely not slow. I don't know the landing speed, but on touchdown it's really slow. The flaps are working quiet fine. With the 12x8 APC-E the maximum current is at 32 A, a bit on the safe side since the motor can stand up to 37 A. The TK4 stays up in the air with 4-10 A, depending on how calm the air is. The weight is now 2600 grams with a 6S3800 accumulator. This is enough for two flights with around 800 mAh reserve at the end. The model is doing fine and I'm getting more and more used to it. Timo Edited By Timo Starkloff on 25/09/2016 17:47:02 Edited By Timo Starkloff on 25/09/2016 17:47:17 Quote Link to comment Share on other sites More sharing options...
Timo Starkloff Posted October 12, 2016 Author Share Posted October 12, 2016 I promised the video and here it is: https://youtu.be/5SEJZ_WXdY0 The video is short and during the landing I needed some corrections. I still have to get used to the short and uneven airfield. I'll try to get a better quality video when the weather is fine. But nevertheless, it's great to have one. Thanks to my brother Timo Edited By Timo Starkloff on 12/10/2016 22:00:40 Quote Link to comment Share on other sites More sharing options...
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