Archived

This topic is now archived and is closed to further replies.

martinlest2

Autothrottle problems

Recommended Posts

Can anyone suggest what the problem may be here? It's very confusing as I can't pin down the cause.I have an a/c (a b737-300) which seems very 'underpowered' in climb. If I increase the throttles manually, with AT disengaged, N1 increases rapidly, but the increase in speed is too gradual, even at under 1000'/min climb rate (at c.20,000'). If I am at around 270KIAS and I set the AT to on and the desired IAS to, say, 300KIAS, instead of N1 increasing, it goes down and the a/c's speed falls. If I disconnect the A/T and push the throttles forward manually, I get a slow speed increase.In the aircraft.cfg I have set thrust_scalar = 1.25, instead of 1.00, but it doesn't stop the speed falling off as soon as I engage the A/T and IAS (AP on, obviously!). Changing the IAS value in the cockpit has no effect on the speed with the AT armed. I have to disconnect the AT and adjust throttles manually.I think it is the fact that the a/c is underpowered during climb that is the main problem. At cruise altitude, things are all fine, and the AT responds to changes in Mach or IAS input, whereas, as I say, engaging the AT/IAS during climb causes the a/c to slow down when it should be speeding up. I thought increasing the thrust_scalar value would have helped more - if I go much above 1.25, the a/c goes wild whilst taxiing..The odd thing is that changing the panel for this a/c doesn't help, and also using the same panel with different a/c causes the same problem, so I have no idea whether the problem lies with the aircraft or the panel!Any ideas on this anyone? Are there any other values in the airctaft.cfg or panel.cfg that would be relevant to this? I've been looking through AircraftContainerSDKFS2004.doc, but haven't had any inspiration as yet. Thanks,Martin

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

This would be a better discussion in the Aircraft and Panels forum... however... :(You're not saying what aircraft it is (as in what freeware/payware).This is sounding like a problem in the .air file.

Share this post


Link to post
Share on other sites

HelloWhich 737s ? If they are freeware Vistaliners,FFX.or any of that lineage then you should definitely have no problems they are very easy to get to altitude.If you where having problems with say the IFDG Abusses i could understand it,they take some getting used to and can be easy to stall on takeoff if you are not on the ball.cheers Andy

Share this post


Link to post
Share on other sites

Hi,Well, it is a Vistaliners 737-300 in fact, though I assumed it was the panel's fault, since I have had this problem with other a/c I use the same panel with. But as I say, changing the panel and rechoosing the VL a/c didn't change a thing today. Maybe I need to shut down and restart FS9 to test that properly - though usually reloading the a/c with a different panel is good enough.It may be the .air file, but I'd have thought the Vistaliners B737_300.air would be oK? (Mine's dated 25/04/2007).M.

Share this post


Link to post
Share on other sites

Hi from Sussex, Martin.Panels won't affect flying characteristics - that's down to the FD. I use my own FD with the VL 737-300; PM me with your email address if you want to try it. Cheers,Martyn :(

Share this post


Link to post
Share on other sites

Have you experimented with this at all in the autopilot?autothrottle_max_rpmmax_throttle_ratescott s..

Share this post


Link to post
Share on other sites

Clearly it's the air file that's at fault - the new one you PM'd me works just fine and solves all the problems I had. Thank you.Martin

Share this post


Link to post
Share on other sites