Mel Jones Posted October 13, 2016 Share Posted October 13, 2016 Can anyone explain to me what elastic flaps are please. Some gliders I have seen for sale are described as having elastic flaps but I am unsure of what exactly they are and how they would work. Quote Link to comment Share on other sites More sharing options...
Trevor Johnson Posted October 13, 2016 Share Posted October 13, 2016 Perhaps they mean Electric Flaps Quote Link to comment Share on other sites More sharing options...
Josip Vrandecic -Mes Posted October 13, 2016 Share Posted October 13, 2016 Dear Mel , flaps are made of an elastic material and here I is an example of the turbine..... Al the best **LINK** Note:Flaps are flexible in order to mitigate the strong dynamic strikes and that the there is no destruction of the same. Edited By Josip Vrandecic -Mes on 13/10/2016 09:42:26 Edited By Josip Vrandecic -Mes on 13/10/2016 09:47:06 Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted October 13, 2016 Share Posted October 13, 2016 Somehow I don't really think that those floppy flaps would be fittind t an aircraft. Quote Link to comment Share on other sites More sharing options...
Gary Binnie Posted October 13, 2016 Share Posted October 13, 2016 I've not seen one but it means that there is no open hinge line, the wing skins are flexible and stretch/contract with flap movement. The full-size Slingsby Vega used the system. Search Jaro Muller Elasto. Quote Link to comment Share on other sites More sharing options...
Gary Binnie Posted October 13, 2016 Share Posted October 13, 2016 Think the Muller website is down at the moment, not unusual! Quote Link to comment Share on other sites More sharing options...
bouncebounce crunch Posted October 14, 2016 Share Posted October 14, 2016 Mel it may also mean that the hinge line is set with a bead of silicon rather than pinned or furry hinges. I have seen this in the past on some floater type gliders. how long it lasts i have no idea as i have never tried this setup. Quote Link to comment Share on other sites More sharing options...
Essjay Posted October 14, 2016 Share Posted October 14, 2016 I wonder if they actually mean "elastic spoilers", where the the flat plate spoilers on the wing top are hinged along their front edge, but are held flat against the wing by an elastic band (or spring). The spoiler is then opened by the action of a servo in the wing, using the servo arm as a cam, and are closed by the tension of the band. I'm sure I've seen it done like this in the past. edit: found this youtube link **LINK** Edited By Essjay on 14/10/2016 07:29:40 Quote Link to comment Share on other sites More sharing options...
Conwy Soarer Posted October 15, 2016 Share Posted October 15, 2016 Gap free hingeing system invented by Grob in the 80s (I think!) very similar to the 'living hinge' system we see in moulded models where the hinged surface is done in the lamination phase. When I find a link will post it. Seem to remember it being used on the Astir sailplane from my full size days in the past. Quote Link to comment Share on other sites More sharing options...
Mel Jones Posted October 24, 2016 Author Share Posted October 24, 2016 Many thanks to all who have responded. All comments have been helpful, thanks again. Quote Link to comment Share on other sites More sharing options...
Robin Colbourne Posted October 24, 2016 Share Posted October 24, 2016 Some indoor hand-launched gliders, had camber on the wing which would give a flapped effect at low speeds, but in the fast launch phase would be flex up and be blown flat by a combination of inertia and the airflow. The Coot 4 is one such example. See the link to the plan in the first message below: **LINK** I wasn't aware of a Grob Astir with flaps, but a quick Google showed that the G104 Speed Astir has a wing just as Conwy Soarer describes. I'm surprised it was justified, as the normal Astir that I fly on occasions, is quite happy down to 36 knots even with a lump like me at the top end of the allowable weight (meaning that the CofG is at the forward end of the range). Edited By Robin Colbourne on 24/10/2016 22:49:08 Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted October 24, 2016 Share Posted October 24, 2016 Probably more relevant in the negative flap positions where the camber change gives lower drag at higher speeds. Any drag from gaps gets more significant related to the square of the speed... Quote Link to comment Share on other sites More sharing options...
Robin Colbourne Posted October 24, 2016 Share Posted October 24, 2016 Martin, Very true, I should have thought of that. I think the only glider I have flown with flaps was a Blanik, which I once saw described as 'a glider which needs flaps to achieve K13 performance...' Quote Link to comment Share on other sites More sharing options...
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