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CAPTAIN SIM FORUM › 757 Captain › 757 version 4.x (FSX ONLY) › Stabilizer Trim and Liftoff

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Stabilizer Trim and Liftoff (Read 6995 times)

DAL191 Senior Member Offline Posts: 388 Location: Tampa FL USA Joined: Nov 26^th, 2009 Gender:	Stabilizer Trim and Liftoff Jun 28^th, 2013 at 5:30am	Print Post
	No screenshots tonight � just a confirmation of what I have known all along and question as to wither other people have the same problem or it is just my installation. This is the situation. Payload 31850, fuel 20000 lbs., GTOW 182726, flaps 5, CG 30%, wind calm, OAT +15C, thrust at derate 2, assumed temp 60, stabilizer trim 3.17, VR 145, and V2 151. Plane liftsoff runway at 100 knots and flys LNAV/VNAV departure even through VR is 145 knots. Stabilizer trim needs to be about �4.0 to keep the plane on the ground until VR at 145 kts. How can a 752 become airborne at 100 kts and fly, accelerate and climb with the thrust significantly reduced? Michael Cubine

	Cooler Master HAF 932 Case, Corsair 1200W PS, Corsair H50 Liquid Cooler,I7-2700K 4.6GHz, ASRock Z68 ProfessionalGen3 MB, 8GB G.Skill RipJaws DDR3 1866 MHz 2-300GB VelociRaptor 10000RPM SATA 16MB Cache, NVIDIA GeForce GTX 780ti, 3072MB, GDDR5, PCIe, ASUS 27" LED Monitor, Windows7 64bit, FSX Gold
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DAL191 Senior Member Offline Posts: 388 Location: Tampa FL USA Joined: Nov 26^th, 2009 Gender:	Re: Stabilizer Trim and Liftoff Reply #1 - Jun 28^th, 2013 at 5:58pm	Print Post
	Exact conditions as previoius takeoff. FMC computed VR at 139 kts not 145 kts but it makes no difference since the 752 will liftoff and fly at a 100 kts. A trim of -4.0 made the plane stay planted on the runway until I rotated at 139 kts. Michael Cubine

	Cooler Master HAF 932 Case, Corsair 1200W PS, Corsair H50 Liquid Cooler,I7-2700K 4.6GHz, ASRock Z68 ProfessionalGen3 MB, 8GB G.Skill RipJaws DDR3 1866 MHz 2-300GB VelociRaptor 10000RPM SATA 16MB Cache, NVIDIA GeForce GTX 780ti, 3072MB, GDDR5, PCIe, ASUS 27" LED Monitor, Windows7 64bit, FSX Gold
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DAL191 Senior Member Offline Posts: 388 Location: Tampa FL USA Joined: Nov 26^th, 2009 Gender:	Re: Stabilizer Trim and Liftoff Reply #2 - Jul 14^th, 2013 at 2:48pm	Print Post
	I think I understand now what I have been doing wrong in regards to the stabilizer trim. When I load the 752 for flight the trim is at 4 on the indicator or 0.0% on Tool Tips. It is neutral - neither APNU or APND. Once the CDU/FMC takeoff page is completed it might show a trim of 2.8. I believed that this was added to the default trim of 4.0 giving me a trim of 6.8 APNU. Since the trim was not a -2.8 I believed it was positive and set the trim to +2.8 using Tool Tips/ This in fact gave me a setting on the horizonatal trim indicator of 6.8 The indicator needs to be set at 2.8 which is in APND range. Now the 752 stays on the ground until I rotate and the trim indicator and Tool Tips agree. See attached image. Michael Cubine

	ElevatorTrim.jpg (Attachment deleted) Cooler Master HAF 932 Case, Corsair 1200W PS, Corsair H50 Liquid Cooler,I7-2700K 4.6GHz, ASRock Z68 ProfessionalGen3 MB, 8GB G.Skill RipJaws DDR3 1866 MHz 2-300GB VelociRaptor 10000RPM SATA 16MB Cache, NVIDIA GeForce GTX 780ti, 3072MB, GDDR5, PCIe, ASUS 27" LED Monitor, Windows7 64bit, FSX Gold
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Markoz CS Team Offline Posts: 12361 Location: Victoria, Australia Joined: Apr 24^th, 2009 Gender:	Re: Stabilizer Trim and Liftoff Reply #3 - Jul 15^th, 2013 at 3:04am	Print Post
	I was never using the cockpit ToolTips for the trim settings on the 752. I always left it at 4 on the Stab Trim Indicator UNTIL v4.6, then I would put it as close as possible to the setting shown in the Takeoff page of the CDU. I see that the ToolTip is showing -2.8 over the Trim Indicator in the VC (in the image), but I have only ever seen the ToolTips there in the 2D Throttle panel. Now I'll have to go and check to see if I can get it to display in the VC like yours. Edited: Just finished checking and the cockpit ToolTip does show.

	Mark Fletcher PC: i7 10700K @3.8/5.1GHz \| 64GB DDR4 3200 \| 12GB RTX 4070 Super \| 32" LCD Monitor \| 1TB SSD & 2x2TB SSD \| Win 11 Pro - FSX/FSX-SE/P3D3/P3D4/P3D5/P3D6/MSFS2020 15.6" Gaming Laptop: i7 7700HQ \| 32GB DDR4 \| 6GB GTX 1060 \| 256GB SSD & 1TB HDD \| Win 10 Pro 64bit - FSX-SE/P3D4
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DAL191 Senior Member Offline Posts: 388 Location: Tampa FL USA Joined: Nov 26^th, 2009 Gender:	Re: Stabilizer Trim and Liftoff Reply #4 - Jul 25^th, 2013 at 12:52pm	Print Post
	DAL191 wrote on Jul 14^th, 2013 at 2:48pm: the trim indicator and Tool Tips agree. Michael Cubine After about 10 more flights and setting the trim indicator to what is shown on the CDU Takeoff page the 752 stays on the ground. However it appears that the agreement between the trim indicator and Tool Tips was just a coincidence of 2.8. At any other setting they do not agree. Michael Cubine

	Cooler Master HAF 932 Case, Corsair 1200W PS, Corsair H50 Liquid Cooler,I7-2700K 4.6GHz, ASRock Z68 ProfessionalGen3 MB, 8GB G.Skill RipJaws DDR3 1866 MHz 2-300GB VelociRaptor 10000RPM SATA 16MB Cache, NVIDIA GeForce GTX 780ti, 3072MB, GDDR5, PCIe, ASUS 27" LED Monitor, Windows7 64bit, FSX Gold
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SEAN ZARELLA Full Member Offline Posts: 36 Joined: Sep 18^th, 2013	Re: Stabilizer Trim and Liftoff Reply #5 - Sep 30^th, 2013 at 7:50pm	Print Post
	thank you for that info i was always using the tooltip to set trim. now using the actual reading on the indicator my responce is much more fluid and no more lifting off the ground @ 100 kias,


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