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#21
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Spoilers or Airbrakes - Whats in a name?
Way back when ... there were terminal velocity dive brakes on gliders. (I
believe another term was DFS dive brakes, but am not sure about that). These brakes would hold the glider below VNe in a vertical dive. At some point, as air foils became thinner, manufacturers agreed that the air brakes would be designed to hold the glider below VNe at a 45 deg. descent angle. I believe this was sanctioned by JAR, IGC, or some such. Spoilers will place no limit on speed and cannot be used in a steep or High Parasitic Drag Approach, whereas airbrakes can be. No one has mentioned an important difference between flaps and airbrakes (whether spoilers, divebrakes, airbrakes, or your term of choice). This difference is the effect had on closing them after having established a stabilized descent under their use. Retracting the airbrakes causes the stall speed to be lowered and the glide angle to improve. If you are low and slow, retracting improves EVERYTHING. If you are low and slow and retract flaps, stall speed goes UP and you might find yourself in the woods, creek, fence, or whatever is short of the touchdown point. At 13:53 17 May 2008, Tony Verhulst wrote: >user wrote: >> I'd continue to use them interchangeably ..... > > If during a positive control check the pilot corrects your call >> of "spoilers," look under the wing for the extra control surface. > >Yes, I've seen at least 2 books (FAA Glider Flying Handbook and Russell >Holtz's Glider Pilot's Handbook of Aeronautical Knowledge)where the >writer claimed that if the ..um.. "device".. extended top surface only >it was a spoiler and if it extended from both survaces it was an air >brake. Seems dubious to me. > >Tony V LS6-b "6N" > |
#22
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Spoilers or Airbrakes - Whats in a name?
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#23
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Spoilers or Airbrakes - Whats in a name?
Poorly stated; corrections inserted.
At 23:10 17 May 2008, Nyal Williams wrote: >Way back when ... there were terminal velocity dive brakes on gliders. (I >believe another term was DFS dive brakes, but am not sure about that). >These brakes would hold the glider below VNe in a vertical dive. At some >point, as air foils became thinner, manufacturers agreed that the air >brakes would be designed to hold the glider below VNe at a 45 deg. descent >angle. I believe this was sanctioned by JAR, IGC, or some such. > >Spoilers will place no limit on speed and [will not be effective] in a steep or >High Parasitic Drag Approach, whereas airbrakes can be. > >No one has mentioned an important difference between flaps and airbrakes >(whether spoilers, divebrakes, airbrakes, or your term of choice). This >difference is the effect had on closing them after having established a >stabilized descent under their use. > >Retracting the airbrakes causes the stall speed to be lowered and the >glide angle to improve. If you are low and slow, retracting improves >EVERYTHING. > >If you are low and slow and retract flaps, stall speed goes UP [the lift DECREASES] and you >might find yourself in the woods, creek, fence, or whatever is short of >the touchdown point. > > >At 13:53 17 May 2008, Tony Verhulst wrote: >>user wrote: >>> I'd continue to use them interchangeably ..... >> > If during a positive control check the pilot corrects your call >>> of "spoilers," look under the wing for the extra >control surface. >> >>Yes, I've seen at least 2 books (FAA Glider Flying Handbook and >Russell >>Holtz's Glider Pilot's Handbook of Aeronautical Knowledge)where the > >>writer claimed that if the ..um.. "device".. extended top >surface only >>it was a spoiler and if it extended from both survaces it was an air >>brake. Seems dubious to me. >> >>Tony V LS6-b "6N" >> > |
#24
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Spoilers or Airbrakes - Whats in a name?
Ralph Jones wrote:
Variometer American Heritage Dictionary A variable inductor used to measure variations in terrestrial magnetism. rj I would say that the "American Heritage Dictionary" has abslutely no electronic knowledge then. :-) ...lew... |
#25
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Spoilers or Airbrakes - Whats in a name?
I'll bet that definition and that instrument are both older than ours --
nad more widespread, probably. At 14:39 19 May 2008, Lew Hartswick wrote: >Ralph Jones wrote: >> Variometer American Heritage Dictionary >> >> A variable inductor used to measure variations in terrestrial >> magnetism. >> >> rj >I would say that the "American Heritage Dictionary" has abslutely >no electronic knowledge then. :-) > ...lew... > |
#26
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Spoilers or Airbrakes - Whats in a name?
Nyal Williams wrote:
I'll bet that definition and that instrument are both older than ours -- nad more widespread, probably. Ralph's point, IMHO, is that you don't go to a general dictionary to get specialized information. Tony V. http://home.comcast.net/~verhulst/SOARING |
#27
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Spoilers or Airbrakes - Whats in a name?
On May 19, 5:25 pm, Tony Verhulst wrote:
Nyal Williams wrote: I'll bet that definition and that instrument are both older than ours -- nad more widespread, probably. Ralph's point, IMHO, is that you don't go to a general dictionary to get specialized information. Tony V.http://home.comcast.net/~verhulst/SOARING Furthermore, you may even want to look elsewhere for general information. Websters is full of definitions like this: Hill - "a raised elevation of land, smaller than a mountain" Mountain - "a raised elevation of land, larger than a hill" no joke. Paul Hanson |
#28
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Spoilers or Airbrakes - Whats in a name?
Hi All, just to be pedantic... If you only partially deploy any device,
it has a different aerodynamic characteristic..... The first stage of Flaps gives an increase in Lift. Second Stage of Flaps gives Lift And Drag. Final Stage of Flaps gives Huge amounts of Drag, without any more Lift. A quick look at your 'Barn Doors' will give you a reasonable idea of what is likely to happen... I cannot imagine that vertical airbrakes would ever give an increase in lift, even if only just cracked open a millimeter or so. Pilot Pete At 20:14 16 May 2008, Andy wrote: On May 16, 8:56=A0am, Mike wrote: According the the original Glasser-Dirks owner's manual for a DG100G, the sailplane has "spoilers". I suspect that the original owner's manual is written in German and that the word "spoilers" is not mentioned. I don't have my Schleicher manual here but I think they call them Klappen. Not being picky for the sake of it, but pointing out that "spoiler" was probably the word chosen by the translator not necessarily by the manufacturer. Andy |
#29
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Spoilers or Airbrakes - Whats in a name?
At 02:32 20 May 2008, sisu1a wrote:
On May 19, 5:25 pm, Tony Verhulst wrote: Nyal Williams wrote: I'll bet that definition and that instrument are both older than ours -- nad more widespread, probably. Ralph's point, IMHO, is that you don't go to a general dictionary to get specialized information. Tony V.http://home.comcast.net/~verhulst/SOARING Furthermore, you may even want to look elsewhere for general information. Websters is full of definitions like this: Hill - "a raised elevation of land, smaller than a mountain" Mountain - "a raised elevation of land, larger than a hill" no joke. Paul Hanson It defines gorse as furze and it defines furze as gorse with no further explanations in either place. My point was that the definition of a variometer is not the property of the soaring community. ;-) |
#30
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Spoilers or Airbrakes - Whats in a name?
On May 20, 6:55 am, Nyal Williams wrote:
At 02:32 20 May 2008, sisu1a wrote: On May 19, 5:25 pm, Tony Verhulst wrote: Nyal Williams wrote: I'll bet that definition and that instrument are both older than ours -- nad more widespread, probably. Ralph's point, IMHO, is that you don't go to a general dictionary to get specialized information. Tony V.http://home.comcast.net/~verhulst/SOARING Furthermore, you may even want to look elsewhere for general information. Websters is full of definitions like this: Hill - "a raised elevation of land, smaller than a mountain" Mountain - "a raised elevation of land, larger than a hill" no joke. Paul Hanson It defines gorse as furze and it defines furze as gorse with no further explanations in either place. My point was that the definition of a variometer is not the property of the soaring community. ;-) Correct! It was the name of a short wave radio part (variable inductance coil = variometer since around 1895) long before it was the name for our sensitive VSI's. http://www.qsl.net/in3otd/variodes.html Paul |
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