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Grila
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Posted 09/09/2012 18:20:32
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Group: Forum Members
Last Active: 27/12/2012 17:29:03
Posts: 12,
Visits: 64
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Hi all,
I'm new to the forum but am hugely impressed with the SD software so far which I intend to put on an iPad 3 soon.
I'm afraid that I seem to be having a complete nightmare when trying to enter the figures into the Weight & Balance boxes and forming the polygon for my FD CTSW (472.5kgs). Everytime I plan a route, I keep seeing the red message: "The aircraft is either overloaded or outside of its acceptable centre of gravity envelope" and it's driving me nuts!!
It's a fairly common light aircraft and I wonder if anyone out there has done all the hard work for me and can post the profile figures for their CTSW on this forum?
Many thanks!
Grila
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stevelup
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Posted 17/09/2012 14:59:43
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Group: Moderators
Last Active: 2 days ago @ 23:42:41
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If you post all the details, I'll gladly create a profile for you, or tell you what to enter.
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Grila
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Posted 19/09/2012 17:20:51
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Group: Forum Members
Last Active: 27/12/2012 17:29:03
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Hi Steve,
Thanks very much for your offer of help!
My aircraft is a Flight Design CTSW.
The MTOW is 472.5 kgs. The Max ZFW is 290.5 kgs. The Max Empty Weight is 290 kgs. The datum is the leading edge of the wing.
(If allowed, the max weight of the aircraft with full fuel (@ 93.6 kgs), 2 x 100 kgs crew and 25 kgs baggage = 608.6 kgs).
The weight is distributed as follows:
Port Wheel: 120 kgs. Position from datum: +0.570 metres (Moment: +68.4 kg.m)
Starboard Wheel: 116 kgs. Position from datum: +0.570 metres (Moment: +66.12 kg.m)
Nose Wheel: 54 kgs. Position from datum: -0.905 metres (Moment: -48.87 kg.m)
Total Moment: +85.65 kg.m
Current Empty Weight = 290 kgs
Empty CG Position: +0.294 metres
Fuel: (2 x 65 litre tanks situated in the wings but considered as one tank):
130 litres = 93.6 kgs. Position from datum: + 0.21 metres (Full Fuel Moment: +19.65 kg.m)
Seat 1:
Minimum Load: 55 kgs. Position from datum: +0.52 metres (Moment: +28.6 kg.m)
Maximum Load: 100 kgs. Position from datum: +0.52 metres (Moment: +52.0 kg.m)
Seat 2:
Maximum Load: 100 kgs. Position from datum: +0.52 metres (Moment: +52.0 kg.m)
Baggage:
Maximum Load: 25 kgs. Position from datum: +1.2 metres (Moment: +30.0 kg.m)
Forward CoG Limit: 0.257 metres
Aft CoG Limit: 0.450 metres
Current Max Forward CoG Position: 0.305 metres
Current Max Aft CoG Position: 0.426 metres
Thanks very much. If you require any other figures, please ask!
Paul
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stevelup
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Posted 21/09/2012 17:38:00
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Group: Moderators
Last Active: 2 days ago @ 23:42:41
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OK, it's pretty simple.
Enter 290kgs for your empty weight
Enter 0.294 as your CoG
In the envelope box:-
0.305,290, 0.305,472.5, 0.426,472.5, 0.426,290
Delete all the existing loading points and start again - it's easier that way.
Do fuel first - make sure you choose 'Add Fuel'
Enter the loading point in the 'Lon' box (0.21) and your default and max (130L) values
Now add Seat 1 with 0.52 in the 'Lon' box. If you always fly, add your default weight in. Now add Seat 2 with 0.52 in the 'Lon' box. If you always fly with a partner, add their weight - otherwise leave blank Finally add your baggage with 1.2 in the 'Lon' box.
I'm a bit confused by this
Forward CoG Limit: 0.257 metresAft CoG Limit: 0.450 metres Current Max Forward CoG Position: 0.305 metres Current Max Aft CoG Position: 0.426 metres
So I went with the figures for 'current' - I don't know why you have two sets of figures? You also listed two MTOW figures - I went with the lower one, but if that isn't correct, change the two 472.5 values in the envelope to 608.6.
21/09/2012 17:39:13 by
stevelup
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Grila
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Posted 21/09/2012 21:28:32
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Group: Forum Members
Last Active: 27/12/2012 17:29:03
Posts: 12,
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Hi Steve,
Many thanks for all that. I do appreciate it.
Just to clarify some points for you.
Forward CoG Limit: 0.257 metres. Aft CoG Limit: 0.450 metres
Current Max Forward CoG Position: 0.305 metres. Current Max Aft CoG Position: 0.426 metres
The first figures are the manufacturer's limits for the fwd and aft positions of the CoG. The second (current) figures are where my CoG limits currently are at minimum and maximum take-off weights. The 608.6 kgs MTOW figure is the manufacturer's design maximum take-off limit. 472.5 kgs is what my aircraft's MTOW is due to being constrained by the UK's Section S microlight requirements. I'm sorry if I caused any confusion!! I just entered a fictious route to check my W&B with my new polygon (which appears as a very regular oblong shape) using 35 litres fuel, 85 kgs in seat 1 and 60 kgs in seat 2 but the green arrow seems to always be a little bit outside the top edge of the polygon. Am I reading things correctly? Regards, Paul
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Grila
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Posted 21/09/2012 21:42:30
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Group: Forum Members
Last Active: 27/12/2012 17:29:03
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Hi Steve,
Due to that confusion between the manufacturer's CoG limits and what my CoG figures were with my current minimum and maximum weights, I have just changed my polygon fugures to use the manufacturer's CoG limits which now read:
0.257,290, 0.257,472.5, 0.450,472.5, 0.450,290
instead of
0.305,290, 0.305,472.5, 0.426,472.5, 0.426,290
However, with my ficticious route, I still get my green arrow outside the top of the box!!
Regards,
Paul
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Grila
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Posted 21/09/2012 21:49:33
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Group: Forum Members
Last Active: 27/12/2012 17:29:03
Posts: 12,
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Hi Steve,
Just a thought but does the fact that the 'plane wouldn't actually fly without the minimum weight of 55 kgs in seat 1 make any difference? Should that be another set of figures added to the polygon string?
Regards,
Paul
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stevelup
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Posted 22/09/2012 10:58:34
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Group: Moderators
Last Active: 2 days ago @ 23:42:41
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Technically yes, but if there wasn't 55kg in at least one of the seats, who would be flying it?
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stevelup
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Posted 22/09/2012 11:04:31
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Group: Moderators
Last Active: 2 days ago @ 23:42:41
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290kg empty weight 145kg of bodies 25kg of fuel === 460kg So I would expect your arrow is right at the top of the box rather than outside it. Is SD actually generating a warning?
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Grila
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Posted 25/09/2012 09:51:23
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Group: Forum Members
Last Active: 27/12/2012 17:29:03
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Hi Steve,
Yes, the arrow is at the top of the box and there is no warning being generated!
Many thanks again.
Paul
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