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Kestrel 19 Questions
Sorry for posting aircraft-specific questions in here, but I haven't
received any responses from my queries in the Kestrel401 forum. I recently bought a Slingsby T59D Kestrel 19. Love the ship Okay, it's big and heavy, but so am I. I need to get my hands on the Addenda for the POH, specifically numbers 3, 4, 5, 6 and 8. Does anyone have a copy that they could photocopy and send to me (I'll pay costs), or scan and e-mail? Slingsby wants 70 GBP for this -- am I naive in thinking that's rather costly? Secondly, I've read on-line that there is a modification to the spoilers to add a second panel and (hopefully) increase their dismal effectiveness. Does anyone have a copy of the information on how to do this, and willing to share? Is the modification approved? How effective is the new setup? The directions used to be posted at gliderpilot.net, but it seems that the files section has not returned up after the unfortunate problems earlier this year. Thirdly, my weight and balance is "odd", to say the least. I've only got a 9-lb range to stay within CoG limits, which seems fairly narrow (same was true for the factory-delivered W&B). Granted, my previous experience was with club ships (1-34, L-33, G-102) which had a wide range. The plane has also flown 40 lbs under min. pilot weight (we goofed) but flew beautifully -- certainly not like an aircraft beyond aft CoG. Is this typical for the Kestrel? TIA, John |
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Kestrel 19 Questions
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Kestrel 19 Questions
Assuming a 36" root chord and an allowable CG range of (e.g.) 25%-40% of
root chord, you'd have an allowable range of CG movement of 5.4" and there's no way a 9-lb increment will move you from outside front to outside rear of such a range on a man-sized glider of Kestrel mass. I'd agree with Bob, where'd the 9# come from? If the ship has been repaired or re-finished, it could have gained significant tail weight and this would require much more cockpit weight to stay within published CG range. Guess that would/could bring the minimum cockpit load up to within 9# of the maximum cockpit load? There is also a maximum weight for non-lifting surfaces (fuselage + pilot) which could be the limiting factor on the high side. Guess it isn't a deal breaker as long as you hit the 9# range. I remember a Nimbus-3 that was in about the same situation. JJ |
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Kestrel 19 Questions
On Oct 29, 8:55*am, JJ Sinclair wrote:
I'd agree with Bob, where'd the 9# come from? If the ship has been repaired or re-finished, it could have gained significant tail weight and this would require much more cockpit weight to stay within published CG range. Guess that would/could bring the minimum cockpit I think I'm running into the max weight consideration. I need to get my calculation sheet and figure out the max pilot without considering gross dry (on the weekend). The factory W&B and placards indicate a pilot weight range from 221 to 229 lbs, with a ship empty weight of 731 lbs. The max landing weight was 960 lbs, so the 229 pilot would hit gross dry weight. The W&B calculations are designed to have min pilot weight giving full aft CoG. I removed 10 lbs of lead from the nose bulkhead -- had a Slingsby stamp on it, so I guess it was installed at the factory. The tail has been repaired, the rudder enlarged, and a repair to a wingtip. New empty weight is 737 lbs -- which indicates 16lbs added for the various repairs. Slingsby also upped the gross dry weight to 990lbs. The new figures are not out of line from the factory, given the change of weight locations (10 lbs out of nose, 15 added to tail). My calculations give a minimum pilot weight of 243 lbs, and simple math puts the max pilot at 253. I'll fully calculate the range when I get to my papers. However, the ship flew quite well with a 200 lb pilot -- he said it handled beautifully. He should have been quite aft of CoG, but it didn't handle like it was too aft... so what gives? As an aside, why would the designers allow for only 80 lbs of water to be carried? Hardly seems worth the effort (I can only carry 50 lbs). I know one pilot wrote a while ago about modifying his Kestrel to carry something like 250 lbs... what would that do to the legal status of the aircraft when flying loaded? Insurance factors when trying to land (over)loaded due to a rope break? Just wondering... Thanks all, John |
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Kestrel 19 Questions
On Oct 29, 3:35*pm, wrote:
My calculations give a minimum pilot weight of 243 lbs, and simple math puts the max pilot at 253. *I'll fully calculate the range when I get to my papers. Found some figures. CoG range is 11.5 - 14.76" aft of datum (leading edge at root) Main wheel weight, 633 # at 2.5" aft Tail wheel weight, 104# at 165.5" aft Pilot sits at 17.2" forward Plug it into the formula, gives min pilot of 247.7# and a max pilot of 359.5# (but I'm limited to 253# due to gross dry weight). Of course, I might be having an off day with the calculator (or messing up my physics); my memory keeps nagging that it's 243 minimum from the W&B pictures and formulae. My test pilot at 200# gives a CoG of 16.39" aft... 1.63" beyond the max aft allowable. Yet, the ship flew beautifully. Very odd, I think. Regards, John |
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Kestrel 19 Questions
John,
Recommend you get a new W&B with you in the cockpit. Some ships fly quite well behind the aft limit (Nimbus-3), but the concern would be; How well do they recover from a spin with an aft GC? Your removing factory weight from the nose and known added aft weight (rudder) would leave me nervous. JJ wrote: On Oct 29, 3:35�pm, wrote: My calculations give a minimum pilot weight of 243 lbs, and simple math puts the max pilot at 253. �I'll fully calculate the range when I get to my papers. Found some figures. CoG range is 11.5 - 14.76" aft of datum (leading edge at root) Main wheel weight, 633 # at 2.5" aft Tail wheel weight, 104# at 165.5" aft Pilot sits at 17.2" forward Plug it into the formula, gives min pilot of 247.7# and a max pilot of 359.5# (but I'm limited to 253# due to gross dry weight). Of course, I might be having an off day with the calculator (or messing up my physics); my memory keeps nagging that it's 243 minimum from the W&B pictures and formulae. My test pilot at 200# gives a CoG of 16.39" aft... 1.63" beyond the max aft allowable. Yet, the ship flew beautifully. Very odd, I think. Regards, John |
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