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#21
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Feds Want to Equipe Gliders With Transponders and Radios
On Apr 28, 9:32*am, Larry Dighera wrote:
On Sun, 27 Apr 2008 12:34:55 -0700 (PDT), WingFlaps wrote in : A radar reflector like they use on weather balloon ought be sufficient. It is just a piece of foil with a large cross section. That's a constructive suggestion. * How large must such a radar reflector be? * It's a retroreflector, I have one in the form of a tube about 3 inches in diameter and 2 feet long. The corner cubes are inside that. I have no idea how effective it is compared to a classic reflector which occupies *a cube about 1 foot across and retroreflects the radar equally in all directions. ... Interesting. *Thanks for the information. * How do you think it might affect a sailplane's L/D? Well, if the sailplane skin is transparent to radar a big reflector could be mounted inside, they don't weigh much. On the other hand a cylinder type reflector could be made quite aerodynamic and even incorporated into (say) the wing tips? Cheers |
#22
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Feds Want to Equipe Gliders With Transponders and Radios
On Sun, 27 Apr 2008 15:03:33 -0700 (PDT), WingFlaps
wrote in : On Apr 28, 9:32*am, Larry Dighera wrote: On Sun, 27 Apr 2008 12:34:55 -0700 (PDT), WingFlaps wrote in : A radar reflector like they use on weather balloon ought be sufficient. It is just a piece of foil with a large cross section. That's a constructive suggestion. * How large must such a radar reflector be? * It's a retroreflector, I have one in the form of a tube about 3 inches in diameter and 2 feet long. The corner cubes are inside that. I have no idea how effective it is compared to a classic reflector which occupies *a cube about 1 foot across and retroreflects the radar equally in all directions. ... Interesting. *Thanks for the information. * How do you think it might affect a sailplane's L/D? Well, if the sailplane skin is transparent to radar a big reflector could be mounted inside, they don't weigh much. On the other hand a cylinder type reflector could be made quite aerodynamic and even incorporated into (say) the wing tips? Cheers That sounds like a very simple, inexpensive and effective solution to the issue. Best of all, the pilot can't turn it off. :-) |
#23
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Feds Want to Equipe Gliders With Transponders and Radios
On Sun, 27 Apr 2008 10:09:57 -0700 (PDT), Andrew Sarangan
wrote: On Apr 27, 12:01 pm, "Vaughn Simon" wrote: "Larry Dighera" wrote in message ... If this is implemented, will it affect powered aircraft without electrical systems too? Almost certainly How much does the gliders right-of-way over powered aircraft affect this issue? Not at all. Any glider pilots who depends on powered aircraft to see them and to automatically get out of their way has a death wish. Right-of-way rules have two uses: 1) Provides a framework of preplanned manuvers for aircraft to use to avoid each other (but only if they both see each other, know the regulations, and are inclined to follow them). And now the big one: (2) It provides lawers and bureaucrats with a methodology for assigning blame after an accident. Is ATC going to take legal and financial responsibility for separation if gliders are mandated to be so equipped and operated? No more than they do now. Is the big-sky-theory a myth? It always has been a myth. No it is not a myth. If you evenly spread the number of GA aircraft below 12,000 ft across the U.S all traveling at random directions, the probability of collision will be extremely low enough to be considered zero. The problem is that the big sky theory does not apply near terminal airspace where the airplanes are not traveling in random directions and altitudes. The spirit of the original transponder exemption was to allow for older airplanes that were manufactured before the days electrical avionics became commonplace. So I can see the justification for this proposal. However, a full blown mode C transponder may not be necessary. A radar reflector like they use on weather balloon ought be sufficient. It is just a piece of foil with a large cross section. *********************************** Does ATC use skin paint any more???? Big John |
#24
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Feds Want to Equipe Gliders With Transponders and Radios
Big John wrote:
However, a full blown mode C transponder may not be necessary. A radar reflector like they use on weather balloon ought be sufficient. It is just a piece of foil with a large cross section. Not really. More like a corner reflector. Take three mutually perpendicular reflecting planes and you get an interesting and useful property -- an incoming beam from any direction gets reflected three times and ends up going out in exactly the same direction it came from. Exactly what you want to give an artificially large radar profile. See here for an example: http://www.landfallnavigation.com/sd152.html In any case, primary radar (even with the help of a passive, if efficient, reflector on the target) only gives you bearing and range. To get altitude, you need Mode C. |
#25
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Feds Want to Equipe Gliders With Transponders and Radios
On Sun, 27 Apr 2008 22:17:44 -0400, Roy Smith wrote in
: Big John wrote: However, a full blown mode C transponder may not be necessary. A radar reflector like they use on weather balloon ought be sufficient. It is just a piece of foil with a large cross section. Not really. More like a corner reflector. Take three mutually perpendicular reflecting planes and you get an interesting and useful property -- an incoming beam from any direction gets reflected three times and ends up going out in exactly the same direction it came from. Exactly what you want to give an artificially large radar profile. See here for an example: http://www.landfallnavigation.com/sd152.html Hey. That looks like just the ticket, and the price is right. Of course, once it's STCed ... Here's the corner reflector definition in Federal Standard 1037C: http://www.its.bldrdoc.gov/fs-1037/dir-009/_1298.htm Photo: http://www.its.bldrdoc.gov/fs-1037/images/coriverc.gif That doesn't look nearly as useful as the example you provided. In any case, primary radar (even with the help of a passive, if efficient, reflector on the target) only gives you bearing and range. To get altitude, you need Mode C. I've had ATC call traffic "altitude unknown" often. I don't see the lack of altitude information as a real limitation, but then I'm neither a controller nor engineer. So while the NTSB in Safety Recommendation A-08-10 through -13 dated March 31, 2008 is recommending removing the glider transponder exemption: The Board notes that, because of the limitations of the see-and-avoid concept, transponder-initiated collision alerts (either from ATC or TCAS) provide both VFR and IFR aircraft with a higher degree of safety in an environment where highspeed closure rates are possible. Therefore, the Safety Board further concludes that transponders are critical to alerting pilots and controllers to the presence of nearby traffic, so that collisions can be avoided, and that gliders should not be exempt from the transponder requirements. This is especially important at higher altitudes, where flight crews may rely more on their TCAS, expecting that other aircraft, including light aircraft, are in contact with ATC and/or are transponder-equipped. Therefore, the Safety Board believes that the FAA should remove the glider exemptions from the FARs that pertain to transponder requirements and use. It would seem that the language the NTSB used leaves room for equipping gliders with a simple passive corner reflector installed within the composite or other non-metallic skin of the glider, thus overcoming the lack of electrical system, and providing ATC with a useable target for potential traffic conflicts. |
#26
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Feds Want to Equipe Gliders With Transponders and Radios
Larry Dighera wrote:
... Interesting. Thanks for the information. How do you think it might affect a sailplane's L/D? Well, if the sailplane skin is transparent to radar a big reflector could be mounted inside, they don't weigh much. On the other hand a cylinder type reflector could be made quite aerodynamic and even incorporated into (say) the wing tips? Cheers That sounds like a very simple, inexpensive and effective solution to the issue. Best of all, the pilot can't turn it off. :-) Locally, approach radar has no trouble finding our transponderless gliders (when we call them), tracking them, and warning/diverting other traffic. We generally do this within 15-20 miles of our towered airports. It works well for us, given the altitudes we fly at. I don't know that a corner reflector would improve on the situation, or if they would detect the gliders without the radio call. While the pilot can't turn it off, it may be the controller doesn't notice it without the radio call, and may not be able to see it because of other clutter, or perhaps the display filter settings. It's worth contacting ATC in your area to see if they are willing and able to do the same for you. It's not practical everywhere, but it's cheap and easy if it is. A problem the reflector can not solve is TCAS will still not detect the glider. This might be deal-breaker for the FAA/NTSB people. -- Eric Greenwell - Washington State, USA * Change "netto" to "net" to email me directly * Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4 * New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more * "A Guide to Self-launching Sailplane Operation" at www.motorglider.org |
#27
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Feds Want to Equipe Gliders With Transponders and Radios
Larry.. DO you fly gliders?
From these statements it would appear that you do not. Gliders may or may not have electrical systems, they do not "generate power", but stored battery power of a limited life span. Gliders are small, batteries are small, everything needs to be small. NTSB "recommends", FAA cannot mandate without a comment period and a change to many CFRs. Technology is coming for the small transponder, along with ATS-B. Why would I put a 50# $15K ATS-B system in a $15K glider. Small transponders now are about $1300 plus antenna and installation. It can be done. My issue is not with TCAS equipped aircraft, but with smaller GA aircraft that do not have TCAS, do not have a Garmin 430 with TIS (or equivalent) and are not talking to ATC. It does no good to have a transponder, when the aircraft causing the traffic conflict is not talking to anyone. Just sitting there FDH and not even paying attention in the traffic pattern. Last Saturday we had at least 4 transient aircraft attempt to land at the airport with 15 to 20 knot tail winds, and against the flow of traffic. They could not even listen up to the radio to figure out the runway in use, or even look at a wind sock or a huge flag and see the 15knt winds and make up their own mind about the landing runway. What makes you think a transponder in a glider would make any difference. And local ATC can see my non-transponder equipped glider just fine, when I am high enough for radar coverage. It's called raw radar skin paint. And yes, I am looking at the requirements (Not Govt' requirement but electical and space in the aircraft requirements) and feasibility for installing transponders in our gliders. B "Larry Dighera" wrote in message ... On Sun, 27 Apr 2008 16:01:31 GMT, "Vaughn Simon" wrote in : "Larry Dighera" wrote in message . .. If this is implemented, will it affect powered aircraft without electrical systems too? Almost certainly That's the way I saw it also. Here are a few pertinent questions: What are the full implications of installing an electrical system in a glider? If implemented, will the requirement for an electrical system kill low-cost glider training operations? Would the CAP glider training operations, which typically provide winch launch and pattern work, be impacted? What are the full implications of installing an electrical system in a Champ or Cub? Isn't their performance so marginal already, that they will become impractical due to increased empty weight and drag, and power reduction with the addition of an alternator, battery, communications radio, transponder, antennas, wiring, switches, etc? Would the work have to be done by an A&P and approved by the FAA for each aircraft/glider modified? Will aircraft/glider useful load be affected? How much does the gliders right-of-way over powered aircraft affect this issue? Not at all. So you don't believe there is any possibility that Part 121 or 135 operator advocate organizations have been lobbying the government to increase the conspicuity of gliders or to enable their TCAS systems to warn operators of glider proximity? What is the possibility of NextGen ATC accommodating non-metallic aircraft without electrical systems? Without transponders? Without radio communications? Any glider pilots who depends on powered aircraft to see them and to automatically get out of their way has a death wish. It's difficult to deny that. But it doesn't address the issue of liability. Right-of-way rules have two uses: 1) Provides a framework of preplanned manuvers for aircraft to use to avoid each other (but only if they both see each other, know the regulations, and are inclined to follow them). Actually, that is true if only one pilot makes visual contact too. And now the big one: (2) It provides lawers and bureaucrats with a methodology for assigning blame after an accident. So Right-of-way regulations provide a basis for aggrieved parties to seek compensation from regulation violators, and assign responsibility too. Is ATC going to take legal and financial responsibility for separation if gliders are mandated to be so equipped and operated? No more than they do now. I would find ATC's responsibility for separating NORDO gliders that paint no primary target to be nonexistent presently. If this proposal is enacted, the situation will change. Is the big-sky-theory a myth? It always has been a myth. At the risk of tangential drift, isn't the BST currently employed by the FAA to separate high-speed military aircraft on VFR low-level Military Training Routs from civil flights? In light of the mythical status of the BST, shouldn't that flaw in the NAS be corrected also? Vaughn Thank you for your insightful comments. |
#28
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Feds Want to Equipe Gliders With Transponders and Radios
"Andrew Sarangan" wrote in message ... On Apr 27, 2:02 pm, Larry Dighera wrote: I think the FAR can be justifiably modified to only exempt airplanes originally manufactured with no electrical system, but all airplanes manufactured since 2008 (or whenever) operating in airspace where a transponder is required should be equipped with one. But not all aircraft are required to have a transponder in all categories of airspace... Sure.. all AIRPLANES with electrical generating systems should have a transponder, but not all AIRCRAFT have electrical generating systems. Even ones built today, sort of a Catch-22. B |
#29
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$1300 transponders?
BT wrote:
Small transponders now are about $1300 plus antenna and installation. It can be done. That's a great price! Where do you get these? What brand? The ones I know about (Becker, Microair) are $1900 plus $200 for the encoder. -- Eric Greenwell - Washington State, USA * Change "netto" to "net" to email me directly * Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4 * New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more * "A Guide to Self-launching Sailplane Operation" at www.motorglider.org |
#30
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Feds Want to Equipe Gliders With Transponders and Radios
On Apr 27, 3:45 pm, Larry Dighera wrote:
On Sun, 27 Apr 2008 15:03:33 -0700 (PDT), WingFlaps wrote in : On Apr 28, 9:32 am, Larry Dighera wrote: On Sun, 27 Apr 2008 12:34:55 -0700 (PDT), WingFlaps wrote in : A radar reflector like they use on weather balloon ought be sufficient. It is just a piece of foil with a large cross section. That's a constructive suggestion. How large must such a radar reflector be? It's a retroreflector, I have one in the form of a tube about 3 inches in diameter and 2 feet long. The corner cubes are inside that. I have no idea how effective it is compared to a classic reflector which occupies a cube about 1 foot across and retroreflects the radar equally in all directions. ... Interesting. Thanks for the information. How do you think it might affect a sailplane's L/D? Well, if the sailplane skin is transparent to radar a big reflector could be mounted inside, they don't weigh much. On the other hand a cylinder type reflector could be made quite aerodynamic and even incorporated into (say) the wing tips? Cheers That sounds like a very simple, inexpensive and effective solution to the issue. Best of all, the pilot can't turn it off. :-) Unfortunately too simple. The problem is NOT ATC's equipment having trouble painting a glider. The problem is the threshold of sensitivity on their radars is set far too high to display us since they intentionally filter out things as slow as a glider, particularly if it's thermalling. We are simply filtered out as clutter (according to the rep Reno sent to address PASCO last winter). That said, I'm sure we don't all read the same on radar, but gliders are not the stealth aircraft they are being made out to be. I believe cockpit alone has a rather large signature, unless of course you paid the extra $1,000,000 for the one molecule thick layer of electrically deposited gold on your canopy. There's more to a stealth aircraft then it being made of fiberglass, or even carbon... Paul |
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