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Delta Foxtrot

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  1. Delta Foxtrot
    Congratulations and all the best!
  2. Delta Foxtrot
    Here is an interesting NACA video on flutter. The type seen on my video is nicely illustrated starting at around 13:10 into the film. I tried to embed the video however none of the instructions in the you tube tools above seem to be available on you tube when using my iPad. **LINK**
  3. Delta Foxtrot
    Geoff, I thought that your name sounded familiar so a quick Google and I can see that we have both been members of the Derby Mercury so I imagine that's is where our paths may have crossed. I was a member in the early 1990s for a couple of years. I continued to ride a lot up until around 2007, but now only ride a few miles to work and back. Small world
  4. Delta Foxtrot
    Posted by Geoff Sleath on 28/12/2015 18:09:40: Posted by Delta Foxtrot on 28/12/2015 16:21:52: Posted by Geoff Sleath on 28/12/2015 14:16:45: Looks pretty violent! Incidentally, is that Ratcliffe on Soar power station in the background? Geoff Yes indeed, well spotted. Are you a member at LEMAC or just keen on power stations! No, but my wife was the station superintendent's secretary back in 1967 when it first opened and we could see it from our bedroom window in Sawley. I could also see it from my desk at work in Sin Fin and used to gauge the progress of spring by noting where the sun rose each morning against the cooling towers. I've cycled past LEMAC many times as well on Long Lane and one of my cycling buddies (Ian Horne) used to be a member there long ago. We now live in Belper and I fly at Ashbourne. I wasn't interested in model aeroplanes back in '67 it was all motor bikes. Geoff Ah! It doesn't seem to be as active these days, there seems to be more days without steam coming out of the tops of the cooling towers.
  5. Delta Foxtrot
    Posted by Steve Hargreaves - Moderator on 28/12/2015 17:47:34: Blimey....I'm amazed it lasted as long as it did..... Were you trying to induce flutter DF or did it come as a nasty surprise? This was an old depron model my dad knocked together. He gave it to me as he has had to pack up and has slowly but surely been passing his stuff on to me. I could see the potential for this to flutter so after confirming this on its first flight I fitted the camera to it to film it. I sat next to an aero elasticity expert at work and I knew he would be interested in it along with other aerodynamicists in the department. For the next flight I repaired the wing and stiffened it with the help of some CF, this increased the airspeed at which flutter was encountered as expected from theory. For the last flight I fitted two coins ahead of the hinge lines on the horn balances. This moved the CoG forward of the hinge line removing the forcing caused by the aileron slop. Flutter was totally eliminated as expected. After this the model had served its purpose for me and it not been flown since. I think that being able to show videos like this to engineering students is a great way to get the theory across. I have done other videos using flow viz to show stall inception on wings. Some of my club mates think I am a bit odd, but it just shows that there are a lot of ways of enjoying the hobby.   Edited By Delta Foxtrot on 28/12/2015 18:27:39
  6. Delta Foxtrot
    Thanks Allan! Very interesting.
  7. Delta Foxtrot
    Thanks Bob!
  8. Delta Foxtrot
    Posted by Geoff Sleath on 28/12/2015 14:16:45: Looks pretty violent! Incidentally, is that Ratcliffe on Soar power station in the background? Geoff Yes indeed, well spotted. Are you a member at LEMAC or just keen on power stations!
  9. Delta Foxtrot
    Link works when pasted into YouTube. I do not know how to actually embed the video on my iPad.
  10. Delta Foxtrot
    First attempt to embed YouTube video, not sure if this will work. Video shows violent nature of wing flutter caused by sloppy aileron on port wing, this ultimately leads to wing failure. Wing was then fixed and further flights conducted, flutter totally eliminated by using two £1 coins taped to horn balances on each aileron. Edited By Steve Hargreaves - Moderator on 28/12/2015 17:41:57
  11. Delta Foxtrot
    I usually photocopy the ribs, formers etc and then use the copies to make these parts. I trace the wing plan onto thick tracing paper for building over, this can be reversed for building the second wing half. The same approach can be taken for the fuselage and formers spacing. Having said all that I find that the plans from the magazine tend to fall apart along the creases towards the end of my builds due to repeated folding and unfolding and the quality of the paper used.
  12. Delta Foxtrot
    HK can be more expensive than you think if you get stung for tax and on top of that have the post office charge for collecting it. If I buy from HK I tend to stick to the UK or European warehouses
  13. Delta Foxtrot
    http://www.modelflying.co.uk/forums/postings.asp?th=94280 Try the thread above. This is for the CAP 21, but the fuselage design is basically the same. I did mine similarly to Gary's and it works quite well. Enjoy the Build!
  14. Delta Foxtrot
    I took advantage of the calm weather and the clocks going back to maiden my CAP early this morning and it did not dissapoint, it flies beautifully. I only had one 4s battery so the flight time was limited, but I managed to trim it out, check out the stall at height and complete 4 take off and landings. The stall was very benign, no wing drop and not much happening in pitch either. I didn't push it too hard as I was only trying to calibrate myself on the speed range prior to flying an approach. There was no wind and on the first couple of approaches I was surprised to see the model shoot past on what appeared to be a reasonable approach speed, it certainly carries a bit of momentum. After a couple of practices the landing was very nice so I had to have a few more turns until the battery was used up. I need to rig more gain on the ailerons as the roll rate was a little low. I can't wait to fly it again and push the envelope with it. Great design! Thanks Peter Edited By Delta Foxtrot on 25/10/2015 14:43:12
  15. Delta Foxtrot
    Thanks Dave! I am only running 4 x 9g MG servos off this BEC so I think 3 amps should be more than enough. I posted originally because I had read that 4S could be an issue, but Geoff has cleared that up for me. I will certainly look at more capable BECs next time I am in the market for ESCs.
  16. Delta Foxtrot
    Thanks for your input Geoff! The model is my latest build a Peter Miller CAP 20L which is approx 4 lb AUW so 500 W should be plenty enough power. I am using analogue servos so I will go with the BEC. I read a warning about 4S in another thread and this was indeed related to a 50 amp ESC with a 2 amp linear BEC.
  17. Delta Foxtrot
    I am planning to use this ESC as part of a 4S 500 W power train, do I need a UBEC? http://www.hobbywing.com/product_show.asp?id=198 The ESC is a hobbyking 60 amp unit with a 3 amp / 5 volts switching mode BEC for use with 2 to 6 cells. I have heard people say that a UBEC should be used with 4S, but I am not sure why? Is this due to a higher switching rates and heat build up? Dave
  18. Delta Foxtrot
    Posted by Paul Cooper _ on 16/10/2015 21:47:44: Have you flown her yet , looks great. Thanks Paul! No I have not yet flown it. I am awaiting delivery of some 4s 3300 mAh lipos, then I need to finalise the prop size to achieve around 450 Watts..
  19. Delta Foxtrot
    Posted by Peter Miller on 16/10/2015 21:32:38: That looks very smart. I took the spats off as soon as I had the flying pictures. They were removed from the full size so still scale, Thanks Peter!
  20. Delta Foxtrot
    Peter, Thanks for your advice on this build. I am pleased that I came back to finish this after parking it last year, the end result looks good and I have learned quite a bit during this build. I have only a few small jobs to do before test flying can start and for me test flying something I have built myself is as good as it gets. I may redo the leg fairings to hide the clamps, for now they are left accessible to allow me to remove the spats if they struggle to cope with our field. Here are a few pics:
  21. Delta Foxtrot

    Delta Foxtrot posted a gallery image in Member Albums

  22. Delta Foxtrot

    Delta Foxtrot posted a gallery image in Member Albums

  23. Delta Foxtrot

    Delta Foxtrot posted a gallery image in Member Albums

  24. Delta Foxtrot
    I am using a purple power Lipo in my dx7s and I will be removing it for charging purposes. I think that the spektrum OEM Lipo could be charged in situ, as it has special circuitry built in, but not a third party Lipo. The other thing that needs to be changed are any low voltage alarm thresholds. This is done on my radio through a battery type setting.
  25. Delta Foxtrot
    Posted by stevejet66 on 09/10/2015 17:51:24: North root and times,**LINK** Timings from departure, but does anyone know the estimated time of departure from Doncaster?
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