Tony Nijhuis Posted September 26, 2015 Share Posted September 26, 2015 Ok so here's the last in the size range of Vulcans I set out to do more than 4 years ago and not off to a great start......a before and after photo I never did like the phrase 'non destructive testing' All I can say is the model when it was flying was superb and cant wait to build the second prototype as the size, simplicity and performance made this a winner... happy days Quote Link to comment Share on other sites More sharing options...
Ian Jones Posted September 26, 2015 Share Posted September 26, 2015 Oh dear that must have been disappointing Tony. Bet there's lots of people waiting for Prototype 2 to succeed in anticipation of the finished design. Trad build twin 90mm fans plus the Vulcan's distinctive good looks, got to be a winner. Hard luck and good luck with the next one! Ian Quote Link to comment Share on other sites More sharing options...
Piers Bowlan Posted September 26, 2015 Share Posted September 26, 2015 Ouch! A very sorry sight, at least the outboard sections of the wings appear to have survived unscathed - small consolation. Any idea what went wrong, so that it is not repeated? What span is this 90mm fan version, 78in? Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted September 26, 2015 Author Share Posted September 26, 2015 Only a slight disappointment Ian.....there is always a greater risk when test flying a design without any sort of covering applied. Of a model this size, one would glass cloth epoxy the structure which locks in great strength. Part of the reason for failure was no covering was applied so i was asking a lot of the balsa. The other reason was too much 'on the hoof' redesigning (cutting & carving) which had weekend the structure What is useful is now i have the wreckage to analyze, i can see where the problem are. There is always a positive to any disaster Yes Piers, 78inch span Quote Link to comment Share on other sites More sharing options...
ChrisB Posted September 26, 2015 Share Posted September 26, 2015 Certainly looks an impressive model Tony. What was the weight? The picture looks like a grass strip. How did it perform off grass? Cheers Chris Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted September 26, 2015 Author Share Posted September 26, 2015 AUW was 18lbs and although the runway was quite boggy on the first test flight, after the last few days of rain and the grass covered the wheels (54mm dia), she fairly raced along and was airbourne in no time. Each fan is capable of 10lbs of thrust so ground power is good...soon as she's away you cut the throttle to two thirds and she climbs away with gusto!...after that, haft to a third throttle is all you need, until you want the 'Vulcan climb'!!!!! Quote Link to comment Share on other sites More sharing options...
Former Member Posted September 26, 2015 Share Posted September 26, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
ChrisB Posted September 26, 2015 Share Posted September 26, 2015 Thanks Tony, certainly looks the part. Yet another top model on my list! Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted September 29, 2015 Author Share Posted September 29, 2015 David, on delta's, tip stalling is not a problem so no washout is required.....What washout does is reduce the wing tip lift and bring it inboard.....QED if the lift is reduce at the tips, the chance of tip stalling is reduced. With the Vulcan wing and the fact delta's do not tip stall, the AVRO designers actually made the tips a flat bottomed high lifting section so the payload carrying capabilities of the Vulcan could be vastly increased with still no chance of tip stall.... Now redesign and the part being cut for a new one........and strangely looking forward to build Quote Link to comment Share on other sites More sharing options...
Former Member Posted September 30, 2015 Share Posted September 30, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Ian Jones Posted September 30, 2015 Share Posted September 30, 2015 With that degree of positive thinking it's bound to be a success.... as usual. Wathcing with great interest. Ian Quote Link to comment Share on other sites More sharing options...
Matt Jones Posted September 30, 2015 Share Posted September 30, 2015 David, I've got a 72" one with the scale section, i.e. LE droop for the outer half of the span. It has very different characteristics in pitch with different speeds which I'm convinced is due to the unusual section. I reckon if Tony can do without them and give a more stable model then all good. Quote Link to comment Share on other sites More sharing options...
Former Member Posted September 30, 2015 Share Posted September 30, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Matt Jones Posted September 30, 2015 Share Posted September 30, 2015 David, it's from the South Herts Models plan, by far the most accurate plan that's out there, and for PSS off the slope. The characteristic is that if you put the nose down even slightly the model accelerates rapidly and becomes incredibly pitch sensitive with a tendency to tuck if left unchecked. I've tried a variety of CG positions without change. It's quite nice to have to 'fly' a model and really focus on what you do but odd none the less. Quote Link to comment Share on other sites More sharing options...
Former Member Posted September 30, 2015 Share Posted September 30, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Matt Jones Posted September 30, 2015 Share Posted September 30, 2015 Absolutely no idea, would have to weigh it. Quote Link to comment Share on other sites More sharing options...
Former Member Posted September 30, 2015 Share Posted September 30, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted September 30, 2015 Author Share Posted September 30, 2015 Interesting point Matt about pitch sensitivity and tuck under....if the wing geometry of your Vulcan is incorrect especially when introducing the under cambered wing profile towards the wing tips (as per the real Vulcan) you are in danger of too much lift behind the CofG. The consequence of this is when you put the nose down the the main inner wing section produces less lift but the out part is still lifting well behind the CofG.....QED as a result the model will pitch down and accelerate and then tuck under....its a vicious circle and only carefully up elevator control (a throttle) can retrieve the situation from desaraster!!! However when the Vulcan wing is in normal level flight or climbing the wing is extremely stable and delivers very high lift characteristics, which is exactly what a bomber had to do. To descend a Vulcan you need to reduce power and keep the nose level then raise the nose slightly and the aircraft descends The rate of decent is check with engine power. On my Vulcan designs I tried to make the wing a little more forgiving so the under camber was not included and so pitch sensitively is not a problem, nor is tuck under. The purist may say its not scale but the idea is to make something that works well rather than a 'scale' hand full in the air.... Quote Link to comment Share on other sites More sharing options...
Former Member Posted October 1, 2015 Share Posted October 1, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
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Keith Simmons Posted October 1, 2015 Share Posted October 1, 2015 David, What about wing area, It should be the same for Empty weight and fully laden. Looks like another typo. Quote Link to comment Share on other sites More sharing options...
Former Member Posted October 1, 2015 Share Posted October 1, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Keith Simmons Posted October 2, 2015 Share Posted October 2, 2015 David, Was the refuelling probe on XJ823 removed for the Falklands War? I understand the RAF went around to collect the probes then, but it was never returned afterwards? Quote Link to comment Share on other sites More sharing options...
Alan Jarvis Posted October 2, 2015 Share Posted October 2, 2015 Keith In April 1997 it received maritime radar reconnaissance modifications (MMR) and a gloss paint finish and served with No 27 Squadron. The bulge on the nose is part of that. It is assumed the probe was removed at that time. Quote Link to comment Share on other sites More sharing options...
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