Chris Walby Posted January 23, 2017 Share Posted January 23, 2017 Advice requested regarding control surface mixing for an inherited Graham Dorschell Vulcan. It has inner and outer control surfaces (no rudder) which I assumed were flaps and elevon, but doubt has set in as it was mentioned that the inner control surface can be elevator only. I can mix almost anything, but I don't have any experience with delta wings of this size. If there are any suggestions could you please include some rational, thanks Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted January 23, 2017 Share Posted January 23, 2017 Inner, is best elevator position Chris, where outer would be the ailerons, for the best authority in the air Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted January 24, 2017 Author Share Posted January 24, 2017 Bounce - Is Denis's advice the entire collective knowledge of the forum members? Very disappointing. Thanks Denis for your help its appreciated, Quote Link to comment Share on other sites More sharing options...
Ian101 Posted January 24, 2017 Share Posted January 24, 2017 Sorry for not responding quicker, I was asleep! My 80 " depron version is inner surfaces elevator only, outer aileron but I also have a rudder. Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted January 24, 2017 Share Posted January 24, 2017 My PSS Vulcan is as Ian above. I do have a switched mix, however, that will drive the elevators as elevons, but I've never needed that high a roll rate. Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted January 24, 2017 Share Posted January 24, 2017 It is as simple as all this advice Chris, the elevators at the centre, ailerons are most effective at the wing tip in most models. Decide if you need a rudder, and for landing, a rudder saves tilting the wings near the ground. You have seen foamie jets do multiple rolls at speed, and these models have the Tx set to Delta wing with elevons for a high roll rate. We really do not need that for the Vulcan, though it would work. You decide, and do low passes setting car alarms off when you can ! Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted January 24, 2017 Author Share Posted January 24, 2017 Thanks guys, I'll do as suggested. Denis, I inherited it and it was nearly fully build with no rudder + its a bit on the porky side so I'll save the weight of another servo! Quote Link to comment Share on other sites More sharing options...
MattyB Posted January 24, 2017 Share Posted January 24, 2017 If your TX can do it set it up with two switch activated flight modes - one using elevators inboard and ailerons outboard, the other using both surfaces together as elevons. Fly it whilst switching between the two to decide which you prefer. You could even have a crow brake setup for landing, though trimming those out can be a pain on flying wings. Full span elevons is the way high performance wings on the slope tend to be setup; this is because inner elevators and outer ailerons can give adverse yaw issues and get draggy when you start pulling hard through turns, though on a true plank like the Bluto the elevator movements are so tiny it's less of an issue. Optimising turn performance probably isn't a major consideration with this model though! Edited By MattyB on 24/01/2017 12:06:24 Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted January 25, 2017 Share Posted January 25, 2017 Fit speed brakes! Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted January 25, 2017 Author Share Posted January 25, 2017 I don't think speed will be an issue for me....power to weigh is a challenge with pusher motors that far back + CofG is another challenge! Batteries are currently in the canopy area and a fair size as well. I am maxed out on props 9x8 so need to dolly launch or it will prop strike & the U/C nose wheel seems to have a mind all of its own! Wing joiners are a mare & ESC wiring is about 4 ft long. Other than that once the building board is clear I'll finish it off and see what happens... Quote Link to comment Share on other sites More sharing options...
Piers Bowlan Posted January 25, 2017 Share Posted January 25, 2017 Those are cracking photos of your Vulcan Andy, which design is it and is it Depron? Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted January 25, 2017 Share Posted January 25, 2017 Thanks Piers, most of these photos are by Phil Cooke, Admiral of the PSSA. She is from the South Herts Models kit - all CNC cut balsa and ply, other than a couple of plastic mouldings for the engine tubes and the bomb-aimer's bubble. Quote Link to comment Share on other sites More sharing options...
Piers Bowlan Posted January 25, 2017 Share Posted January 25, 2017 Fabulous, and thanks for the info, I have made a note of that for when I have more space and time. Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted January 25, 2017 Share Posted January 25, 2017 The designer wrote this Chris, picture to follow I decided to use the previous prop powered Vulcan plan as the basis for my new design. This model used two outrunner motors rated at 540 Watts, supplied by two 3-cell LiPo batteries. The motors turned 8x6 props. The current was not measured so I don't know their power consumption. Being new to electric ducted fan power, at first I thought that I could use a pair of 70mm EDF units, but I was advised that this would not be enough for such a large model. Various fan possibilities for the power system were considered such as a single 110mm fan with bifurcated ducting, or two 90mm fans, or even four 70 mm fans. After considering these options, it was decided the electric power system for this model would use four 70mm fans, to be supplied by four 3S LiPo batteries Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted January 25, 2017 Share Posted January 25, 2017 Is there not room for a less pitchy pair of props? Quote Link to comment Share on other sites More sharing options...
eflightray Posted January 25, 2017 Share Posted January 25, 2017 My scratch built in Depron, 82 " span -- Ray. Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted January 25, 2017 Share Posted January 25, 2017 Andy Meade flying his Avro Vulcan August 2016. Quote Link to comment Share on other sites More sharing options...
Craig Kane Posted February 24, 2017 Share Posted February 24, 2017 Hi guys, Fantastic models. Found this post as I was doing some research for my Nimrod project (Chris Golds plan). The model will be 86" wingspan and come out around 7lbs in weight. It calls for 4x Speed 400 motors driving 5" props. From experience, I have found that 2826/6 2200KV motors on 6x4 props give about 270w on 3s. Do you think that 4 of these would be enough? Edited By Craig Kane on 24/02/2017 10:43:10 Quote Link to comment Share on other sites More sharing options...
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