LanceB Posted August 21, 2014 Share Posted August 21, 2014 Just curious, but when building an active Viggen that has been parked but is armed, what should be drooped and/or open? Elevators on the canards and upper thrust reverser petal I know drooped after shutdown. Lower airbrakes often seem to be open in pics. Inner MLG doors generally look to be closed on the ground on active aircraft? Flaps/ailerons seem to go either way based on what pics I can find, so is "full up" OK, or did they droop as well normally? TIA Quote Link to post Share on other sites
JFVicente Posted August 21, 2014 Share Posted August 21, 2014 (edited) Hi Lance! You are right about the elevators on the canards and the MLG doors, wich are usually closed except for working on the gera bay. Other door wich is always open on the ground id the ram air turbine wich opens automatically when the aircraft touchs the ground: http://www.arcair.com/awa01/101-200/awa200-viggen/part2/images_Niklas_Knutzen/gen_front.jpg http://www.arcair.com/awa01/101-200/awa200-viggen/part2/images_Niklas_Knutzen/gen_back.jpg You can buy it as a resin set from Maestro Models in both 1/48 and 1/72 scale: http://www.rebell.com/saab-37-viggen-rat-and-fod-guards.html http://www.rebell.com/rat-ram-air-turbine-for-saab-37-viggen.html HTH. Juan Edited August 21, 2014 by JFVicente Quote Link to post Share on other sites
LanceB Posted August 21, 2014 Author Share Posted August 21, 2014 Thanks Juan - I knew about the Maestro sets, didn't realize they were a "must" if the aircraft was parked. I will add that to the list. Good news about MLG doors, that saves me any work trying to make that area of the gear bay look better or cleaning up ejector pin marks inside the doors. The flaps/ailerons are a concern, it would be a bit of work to cut them out and reposition, more so than the elevators, but I wouldn't want things to be "out of synch" - in other words, I have heard it takes a little bit of time for the hydraulic pressure to bleed off and the upper thrust reverser petal to droop. If the flaps also droop over time, it might look odd to have the thrust reverser drooped but flaps neutral? Quote Link to post Share on other sites
Hoops Posted August 21, 2014 Share Posted August 21, 2014 (edited) I'm pretty sure that the ground crew will close the ram air turbine door as part of the post flight, however. I lots of pictures with it closed as well as open on the ground. Having something like that open all the time is asking for a bird to make a nest in there, or for something to break after being exposed to the elements. Hoops Edited February 14, 2015 by Hoops Quote Link to post Share on other sites
LanceB Posted August 23, 2014 Author Share Posted August 23, 2014 Having something like that open all the time is asking for a bird to make a next in there, or for something to break after being exposed to the elements. Good point - plus as I think about it, a permanently deployed RAT would be almost permanently spinning, and that is going to seriously shorten component life. Any thought on the ailerons/flaps? Do those normally droop over time (like the thrust reverser petal)? Quote Link to post Share on other sites
Flankerman Posted August 23, 2014 Share Posted August 23, 2014 If you really wanted something different, you could always fold the fin....... Ken Quote Link to post Share on other sites
TobHol Posted August 23, 2014 Share Posted August 23, 2014 The RAT was deployed when the landning gear was lowered. It was always deployed until the gear went up the next flight during normal operation. Inside there is the oxygene and nitrogene refill that needed attention between flights. Also during engine starup the fire extinguisher is located behind the RAT. Note that the layout behind the RAT is different between the AJ and JA. If the aircraft is parked the hatch on the right side, under the canard, is open. The main electrical switch is located there, Also much of the fuses are there. As for the flaperons they were always hanging a bit while on ground and the hydraulic systems off. /Tobias, former Viggen mechanic Quote Link to post Share on other sites
Hoops Posted August 23, 2014 Share Posted August 23, 2014 Tobias, thank you for adding some very insightful information to the discussion. I have many of pictures on my hard drive (and can be found on airliners.net for example) of Viggens with the landing gear down in all configurations (approach, landing, taxi, parked) where the RAT is not deployed. Examples: Landing: http://www.airliners.net/photo/Sweden---Air/Saab-JA37DI-Viggen/1341615/ Approach: http://www.airliners.net/photo/Sweden---Air/Saab-SK37-Viggen/1340589/ Gear down flight for photo op?: http://www.airliners.net/photo/Sweden---Air/Saab-AJSF37-Viggen/1423616/ Parked on flighline: http://www.airliners.net/photo/Sweden---Air/Saab-JA37D-Viggen/1427878/ It is by no means the majority of the time it seems, why is it closed some of the time, but not all? Thanks again for the info, Hoops Quote Link to post Share on other sites
LanceB Posted August 23, 2014 Author Share Posted August 23, 2014 Thank you Tobias. The hatch on the right you spoke of would be the one in this pic, inside of which is this pic? Quote Link to post Share on other sites
TobHol Posted August 23, 2014 Share Posted August 23, 2014 Hoops: You making me uncertain, the first three examples you use are modified a/c at the end of the Viggen era. It is possible that the sequence was changed during these upgrades, I need to investigate further, I will post the answers then I have them. BUT the last parked picture you show all FOD covers are on, this also include closing the RAT. It was very unusual to install all covers, I think I only did it once for practice during my time. LanceB: Yes, that is the one. Please noter that there are different layouts here as well between AJ and JA. /Tobias Quote Link to post Share on other sites
Paolo Maglio Posted February 14, 2015 Share Posted February 14, 2015 RAM turbine was later modified to open only when the oleo of the front gear was compressed and vice-versa. Quote Link to post Share on other sites
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