Vinegar Dave Posted May 12, 2015 Share Posted May 12, 2015 So when does a glider stop becoming a glider and is a plane?. What are the BMFA rules on this. What in the BMFA book to say if you were taking a test would that be. I saw a aircraft which i was told was a glider which certainly had the wingspan ( maybe there is a limit in length) but had a fair size motor at the front & undercarriage,,, Quote Link to comment Share on other sites More sharing options...
Gary Manuel Posted May 12, 2015 Share Posted May 12, 2015 My understanding is that a glider is defined by its "ability to maintain sustained un-powered flight". Simple as that. Quote Link to comment Share on other sites More sharing options...
eflightray Posted May 12, 2015 Share Posted May 12, 2015 Personally I would class a glider as unpowered at all times, then you get a motor-glider, but may modelers and manufacturers will call a powered glider just a glider. The media will often call a multi-rotor a quadcopter, no matter how many motors it has, or just a drone. A plane, is wood working tool or an engineering/architectural description of a flat surface. An airplane (USA) is ...... an aeroplane (UK) ....... is what we play with. Life gets too complicated Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted May 12, 2015 Share Posted May 12, 2015 I believe that the A and B test info states that the model used must be able to perform the required tasks along with a minimum weight. I guess for the silent flight scheme that would mean that the model used would need to perform the tasks unpowered, while for the power scheme it needs to take off under it's own power. By those measures a power assisted glider with undercarriage qualifies as a powered model. Whether it would qualify as a glider for the silent flight test is another matter. Have you looked on the BMFA site in the advice for candidates and examiners' guides for each type of test? Looks like their are various options available to cover thermal, slope and electric silent flight types - here Edited By Bob Cotsford on 12/05/2015 15:26:46 Quote Link to comment Share on other sites More sharing options...
Cuban8 Posted May 12, 2015 Share Posted May 12, 2015 Interesting question. Not too sure about "ability to maintain sustained non -powered flight", I suppose that would give us a perpetual motion aircraft! Any aircraft can become a glider, in the case of a Cessna 150 or Boeing 747 - shut the power down and you'll have a glider (not a very good one though). Perhaps it's more to do with aerodynamics? Have an aircraft with a low wing loading and high lift to drag ratio and you'll have something that will descend quite slowly(under gravity) compared to something with characteristics that are quite the opposite. Design specifically for those good duration properties and you'll end up with what we'd recognize as a glider i.e slender fuselage, long thin wings etc. rather that say a WW1 fighter. Edited By Cuban8 on 12/05/2015 15:35:44 Quote Link to comment Share on other sites More sharing options...
The Wright Stuff Posted May 12, 2015 Share Posted May 12, 2015 Posted by Cuban8 on 12/05/2015 15:32:04: Interesting question. Not too sure about "ability to maintain sustained non -powered flight", I suppose that would give us a perpetual motion aircraft! Nope, if it takes energy from external source to stay up (i.e. the wind) then it's a perfectly legitimate physics-abiding craft! Personally I would say it's really just about design intent, rather than any material properties of the aircraft itself. A glider is an aircraft for which the primary intention/purpose is that it spends most of its flight unpowered, and thus is optimized as such in its design. Quote Link to comment Share on other sites More sharing options...
Vinegar Dave Posted May 12, 2015 Author Share Posted May 12, 2015 Posted by Bob Cotsford on 12/05/2015 15:23:41: I believe that the A and B test info states that the model used must be able to perform the required tasks along with a minimum weight. I guess for the silent flight scheme that would mean that the model used would need to perform the tasks unpowered, while for the power scheme it needs to take off under it's own power. By those measures a power assisted glider with undercarriage qualifies as a powered model. Whether it would qualify as a glider for the silent flight test is another matter. Have you looked on the BMFA site in the advice for candidates and examiners' guides for each type of test? Looks like their are various options available to cover thermal, slope and electric silent flight types - here Edited By Bob Cotsford on 12/05/2015 15:26:46 It seems very vague in there and not much about it?. I want to find out so i can make sure i have the appropriate glider. Perhaps there is a motorised and non motorised glider certificate , i would imagine that 'part' of the requirment is to have a limited wingspan size . There must be a BMFA examiner on the forum somewhere ho can tell us? Edited By Vinegar Dave on 12/05/2015 17:21:52 Quote Link to comment Share on other sites More sharing options...
jrman Posted May 12, 2015 Share Posted May 12, 2015 Perhaps this helps. It's from the BMFA Guidance notes that Bob referred to. Electric Powered Glider The test can be performed with virtually any Electric Powered Glider model, but not an Electric Powered Sports model as the Powered Flight 'A' Certificate would be more appropriate to that type of model. " Unpowered Glider The test can be performed with virtually any Thermal Soaring Glider model and launch may be by Hand Tow, Bungee, Winch, Hand Launch or Aero-Tow. The test will not be taken with electric powered gliders Whatever model is brought by the candidate, it must be suitable to fly the manoeuvres required by the test they are taking. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted May 12, 2015 Share Posted May 12, 2015 I'm not sure where any confusion comes from. There are silent flight A tests for electric powered, slope and thermal variants of gliders, as Bob states. The only one with a motor is the first one. The post above which I overlapped sums it up very well! Edited By Martin Harris on 12/05/2015 18:01:05 Quote Link to comment Share on other sites More sharing options...
Gary Manuel Posted May 12, 2015 Share Posted May 12, 2015 Posted by The Wright Stuff on 12/05/2015 15:47:46: Posted by Cuban8 on 12/05/2015 15:32:04: Interesting question. Not too sure about "ability to maintain sustained non -powered flight", I suppose that would give us a perpetual motion aircraft! Nope, if it takes energy from external source to stay up (i.e. the wind) then it's a perfectly legitimate physics-abiding craft! Personally I would say it's really just about design intent, rather than any material properties of the aircraft itself. A glider is an aircraft for which the primary intention/purpose is that it spends most of its flight unpowered, and thus is optimized as such in its design. Is this the ultimate glider then? Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted May 12, 2015 Share Posted May 12, 2015 Not with all those propellers whirling away! Quote Link to comment Share on other sites More sharing options...
Vinegar Dave Posted May 12, 2015 Author Share Posted May 12, 2015 Just to add to the pot i am presuming there must be a weight for the glider so am i right in saying that the A certificate in fixed wing includes the battary to make up the 1KG and if so is this the case for a powered glider? And to add can the glider A certificate be taken without the fixed wing certificate if you just want to fly gliders? Edited By Vinegar Dave on 12/05/2015 20:10:33 Quote Link to comment Share on other sites More sharing options...
Geoff S Posted May 12, 2015 Share Posted May 12, 2015 Posted by Vinegar Dave on 12/05/2015 07:22:43: So when does a glider stop becoming a glider and is a plane?. What are the BMFA rules on this. All gliders are 'planes but not all 'planes are gliders. Geoff Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted May 12, 2015 Share Posted May 12, 2015 Posted by Vinegar Dave on 12/05/2015 20:08:30: Just to add to the pot i am presuming there must be a weight for the glider so am i right in saying that the A certificate in fixed wing includes the battary to make up the 1KG and if so is this the case for a powered glider? And to add can the glider A certificate be taken without the fixed wing certificate if you just want to fly gliders? Edited By Vinegar Dave on 12/05/2015 20:10:33 No minimum weight for gliders and you can take any A certificates in any order. You only need a particular A if you want to take a B in that discipline. All examiners are able to examine As in any discipline - it's only for a B that the lead examiner has to be qualified for the type. Edited By Martin Harris on 12/05/2015 20:30:12 Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted May 12, 2015 Share Posted May 12, 2015 The definition in the A Test rules leave it basically up to the examiner to decide, the wording says one has to be a glider/motor glider and not a sports power plane, the other says it has to be a plane of at least 1kg (inc batts) and have wheels but it cant be a glider/motor glider Not exactly a clear cut definition....... so where would a Bixler 3 sit? It can be made to weight 1kg, it can have wheels....... Quote Link to comment Share on other sites More sharing options...
Vinegar Dave Posted May 13, 2015 Author Share Posted May 13, 2015 I guess if the rule states you can take any A certificate in 'ANY' order that sums it up but is a pusher a glider? Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted May 13, 2015 Share Posted May 13, 2015 Could be... Examiners aren't there to make life difficult and should tell you which test is appropriate. Quote Link to comment Share on other sites More sharing options...
Vinegar Dave Posted May 20, 2015 Author Share Posted May 20, 2015 The Bixler 3 is deemed as a fixed wing as it has undercarriage and a prop but on a A test i dont think it would be heavy enough unless you stuck a 60 motor on it with a 6s battary at 5000 amps....Now that would be amusing to watch Quote Link to comment Share on other sites More sharing options...
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