Jump to content

Simon Chaddock

Members
  • Posts

    9,427
  • Joined

  • Last visited

  • Days Won

    14

Simon Chaddock last won the day on May 7

Simon Chaddock had the most liked content!

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

Simon Chaddock's Achievements

360

Reputation

  1. The Fairey Albacore certainly has dihedral but not that much.
  2. Same here in Cheshire but "Make hay while the sun shines". In a few days the wind and rain will return.
  3. Fitting the top part of the nacelle back proved to be quite an exercise as the Depron duct is 6mm larger OD compared to the single wall printed one so it required an insert or both the skin and the formers either side. It also requires quite a bit of "skin adjustment" to get it to match up cleanly with the printed inlet and exhaust. The canopy and windscreen have been removed. The ESC, UBEC and battery box are rather "lost" in the huge space! What was the removable canopy will be fixed in place. The windscreen will now be removable and become the battery hatch. I am still not exactly over confident it will fly
  4. Of course on the full size the wings are completely floppy without the struts. Still an amazing degree of detail.
  5. Took some careful fitting and adjustment as well as running the motors wires (0.7 mm magnet wire) all the way along the underside duct it was eventually glued on to the lower half of the nacelle. Not easy to ensure all 7 formers had glue and made contact with the duct. The motor wires have been brought forward into the cockpit. I intend to use an 850 mAh 5s LiPo. Its current ESC is only good to 4s so before going any further with restoring the fuselage the next job is to temporarily install a 6s ESC and a servo tester so the duct can be tested at full power. Compared to the space inside the fuselage the ESC and UBEC are both tiny and light. With the motor now right at the back of the duct I expect the battery will have to well forward so the internal layout of the cockpit/battery hatch will have to be substantially altered. Never that simple with such a light construction.
  6. Having made the decision to instal the test duct into the Depron HE162 the next problem was how to actually do it. For its size it is a very light basically hollow airframe that relies entirely on its skin for strength and rigidity. The danger being that by cutting open enough area to install the complete duct it could make the rest of the airframe too 'wobbly' to be handlable. Eventually I bit the bullet and chose to cut the nacelle along the centre line of the duct, either side, front to back. In the process it would destroy the printed duct but that was going to be scrapped anyway. Done this way it would mean the lower half of the duct would remain in place on the fuselage so retaining a degree of fuselage rigidity and not disturbing the wing mounting. To my relief it actually worked quite well. Note the oversize tail fins installed earlier to try to improve its flight characteristics. Once open it does rather highlight the delicate nature of the structure. It is all just 2 mm Depron. Now I have to work out how to fit and glue in the Depron duct to all the formers without breaking too much of anything. On a lighter note what you don't see in the above picture is my daughter's ChiHuaHua asleep on the bed! She likes both comfort and human company.
  7. After hanging on the wall for nearly a year I decided to have another go with it or rather to see if I could get a bit more thrust and save some weight. A test rear motor mount retaining the same 2205 drone motor with a scale after body that reduces the nozzle to 95% of the FSA. It will use a 3 blade 3x4.5 'wide blade' prop rather than the 4 blade 3x3.5. The duct itself is rolled 3 mm Depron with printed joining pieces. It has a printed bell mouth. Overall this duct is some 20 g lighter than the printed. Not that much but every little helps. The difference in thrust is remarkable. https://www.youtube.com/watch?v=pWhRDJSJNsY On a 4s it delivers close to 250 g thrust using 10A (149W). It certainly passes my 'blow the door shut' test. The ESC can be changed for a 30A 6s version if required. This is so much of an advance over the previous arrangement I will simply substitute this duct slightly extended into the HE 162. It appears the coarser pitch prop is much betterable to handle the effect of the long duct. No guarantee but I might yet get the Depron HE162 to fly.
  8. Ron Very neat, but it does seem a bit perverse to go from a round to a square when the motor itself is circular.
  9. It is worth remembering that any thrust angle change (or trim) can only create level flight at one specific air speed and thus one power setting. This was a practical situation for un- throttled free flight planes but not so relevant for full house RC or full size. Of course if you throw in a 6 axis gyro with GPS the effect of throttle changes can be almost completely mitigated.
  10. To my understanding 'downthrust' is an attempt to reduce the effect of the difference between the thrust line and the centre of drag. The centre of drag is entirely dependent on the configurtion of the airframe. It follows that the airframe configuration and the physical value of its thrust have to be considered to determine what effect a change in thrsut line may have. For example the effect of down thrust will be completely different between a high and low wing design.
  11. I did actually fly it yesterday with no problem except my video camera refused to play so sorry no video. The only issue was the complete lack of wind. Fine for the actual flight but the limited grip on the fuselage made it hard to impart almost any 'urge', I could dee the gtro deflecting the ailerons as it tried to keep the wing level until it had accerated a bit. It flies so slowly the hand launch is no problem in even a gentle breeze but in a true 'nil' wind it is not so good. I should have flown again late this evening (another nil wind) but I was involved in restoring the end of its 'curled up' wing tips and andding small 'finger grips' to the fuselage to give a better hand launch. Still the plus side of a 'no flight' is the A350 is still available for the next time!
  12. To be exact setting the throttle range is not an EDF paculiarity but it applies to any ESC that does not have an "auto throttle range" capability.
  13. The replacement motor mount, pylon and exhaust duct withthe Emax 2205 installed. The exhaust interior and the tail cone are painted a plausible dark sea grey. The tail cone apart from giving a scale appearance also retricts the exhaust to 95% of the FSA which increases the static thrust be some 5%. Every little helps. The complete RH nacelle installed in the wing and painted. The nose completed with the new black Fablon windscreen outline. It always was a bit of a crude solution but it is light! Hopefully I will be able to actually test it this evening with a video
  14. The story continues. I did fly it again on the 23 March, well sort of! https://www.youtube.com/watch?v=fScE_1Ygcbs I really should have known better but I suspect it was a case of "I am here so I will fly". Clearly the RH motor was not performing as it should with the inevitable results. I probably could have managed if the motor had failed in flight but on a hand launch - no way! The damage was not that severe, just a crushed nose but with everything permanently 'built in' finding out what was wrong withhte RH nacelle and putting it right would likely be a major job. After hanging on the wall for nearly a month I felt I had to make a start. Having plenty of construction pictures is a great help in determining exactly where everything is under the skin and where to cut! So first cut back the nose to a 'sound' former and make good any locally damged skin. Infact even the sound former was replaced with an identical one but twice as wide, 4 mm rather than 2mm) to give a surface to stick the new skin planks on to. Thank goodness I had kept all the FreeCad files. At this point I knew I could rebuild the nose so I turned to the problem with the RH motor and/or its ESC. Cutting open the wing underside exposed the Little Bee 20A opto ESCs. To my delight I had connected them using 2mm bullet connectors making it possible to test the motor iindependently with another ESC than was known to work. It confirmed the motor was the problem. To extract and replace the motor was going to involve destroying the motor mount and the nacelle pylon. As can be seen in the picture at least the inlet duct of the nacelle couldbe saved for reuse. Having extracted the motor a close inspection revealed the problem. Claerly one winding was seriously 'cooked'. Then I discovered that this LDPOWER 2204 2300kV motor is a 'discontinued item' as fas a Hobby King are concerned, but then I did by the original CW & CCW pair in 2010! Fortunately i did have a spare vitually identical CW Emax 2205 2300Kv motor that fortunately uses the same pich mounting holes and is actually 2g lighter. The whole nacelle pylon, motor mounting and exhaust duct is a one piece part so 3D printing 'saved' me again! To be continued.
  15. Robert Well done on your A test but it is a bit like the driving test. You have demonstrated the ability to fly a plane competently but not yet how to spot when trouble might develop and how to stop it developing further. As every situation is likely to be different it a skill that requires both judgement & experience. One needs practise the other needs time & understanding. For learning purposes the best crash is the one you just avaoided by your own efforts rather than by pure luck.
×
×
  • Create New...