ragedracer1977 Posted January 29, 2019 Report Posted January 29, 2019 Did you know that the horizon isn't adjustable in flight? It's set on the ground, and that's what you get. It's a little weird not being able to adjust a degree or 2 based on your flight profile. Quote
kpaul Posted January 29, 2019 Report Posted January 29, 2019 51 minutes ago, ragedracer1977 said: Did you know that the horizon isn't adjustable in flight? It's set on the ground, and that's what you get. It's a little weird not being able to adjust a degree or 2 based on your flight profile. Yep, just like every other glass ADI I have flown behind, to include C-130s, PC-12s and Beech 400s. 1 Quote
carusoam Posted January 29, 2019 Report Posted January 29, 2019 Wouldn’t that be an issue when your ground attitude is not flight level attitude? The Long Body Mooney has a few degrees nose up while on the ground... Possibly about 4° up(?)... So, a tail dragger would have a more significant challenge... I think the instructions might need some additional fine tuned reading or fined tuned writing.... Or the adjustment takes a bracketing routine each time you fly... If off by a few degrees in flight, adjust it the few degrees while on the ground... Realistically, I never touch mine. The mechanical gauge gets adjusted for being level & the angle for parallax... based on the pilot’s sitting height... only one pilot flys my plane, so this parallax never gets adjusted... Digital displays have no parallax issues... Fun stuff! Best regards, -a- Quote
ragedracer1977 Posted January 29, 2019 Author Report Posted January 29, 2019 5 minutes ago, kpaul said: Yep, just like every other glass ADI I have flown behind, to include C-130s, PC-12s and Beech 400s. This is the first glass I've ever used. I read the explanation from Garmin and it sorta makes sense. The horizon doesn't move. The G5 reflects where the horizon is, not your pitch attitude to an artificial horizon. My CFII really drilled into me resetting the horizon once in cruise, this is gonna take a while to get used to. 1 Quote
kpaul Posted January 29, 2019 Report Posted January 29, 2019 1 minute ago, carusoam said: Wouldn’t that be an issue when your ground attitude is not flight level attitude? Not really. Level flight can occur at many different attitudes, all dependent on speed and configuration. 1 Quote
ragedracer1977 Posted January 29, 2019 Author Report Posted January 29, 2019 1 minute ago, carusoam said: Wouldn’t that be an issue when your ground attitude is not flight level attitude? The Long Body Mooney has a few degrees nose up while on the ground... Possibly about 4° up(?)... So, a tail dragger would have a more significant challenge... I think the instructions might need some additional fine tuned reading or fined tuned writing.... Best regards, -a- The horizon is level when the plane is level. But if your cg is a little aft or forward, you're light or heavy, "level" doesn't necessarily reflect the relationship of the instrument to the horizon. Did that make any sense Quote
ragedracer1977 Posted January 29, 2019 Author Report Posted January 29, 2019 Think about this Anthony. You're in landing configuration. You're behind the power curve. You're full power, just maintaining altitude. What is your pitch relative to the horizon? What would happen if you adjusted your AI to match that new "level flight attitude"? Quote
carusoam Posted January 29, 2019 Report Posted January 29, 2019 I like hanging with you guys! There is so much to know, and extra stuff to think about. Best regards, -a- Quote
rbridges Posted January 29, 2019 Report Posted January 29, 2019 1 hour ago, ragedracer1977 said: This is the first glass I've ever used. I read the explanation from Garmin and it sorta makes sense. The horizon doesn't move. The G5 reflects where the horizon is, not your pitch attitude to an artificial horizon. My CFII really drilled into me resetting the horizon once in cruise, this is gonna take a while to get used to. same with me. when I started using the aspen, it surprised me to learn that the horizon wasn't adjustable. Quote
Marauder Posted January 29, 2019 Report Posted January 29, 2019 Think about this Anthony. You're in landing configuration. You're behind the power curve. You're full power, just maintaining altitude. What is your pitch relative to the horizon? What would happen if you adjusted your AI to match that new "level flight attitude"? What is interesting is that I have two different electronic AIs. The Aspen and the L-3 ESI-500. When the Aspen boots up, I don’t see any indications that it is aligning (at least that I can recall). The ESI on the other hand is clearly doing an alignment function. The ESI also says it can be recalibrated in flight but cautions that it has to be done in level flight without acceleration. I have never needed to recalibrate.This is what they look like on the ground. If you look closely, you’ll see both AIs are showing about 3° nose up attitude. This is what I normally see on the ground. So whatever calibration these units do, I’m pretty confident they don’t need in flight calibration. They always match each other. And in flight. Sent from my iPad using Tapatalk Pro 1 Quote
Bob - S50 Posted January 29, 2019 Report Posted January 29, 2019 1 hour ago, carusoam said: Wouldn’t that be an issue when your ground attitude is not flight level attitude? The Long Body Mooney has a few degrees nose up while on the ground... Possibly about 4° up(?)... So, a tail dragger would have a more significant challenge... I think the instructions might need some additional fine tuned reading or fined tuned writing.... Or the adjustment takes a bracketing routine each time you fly... If off by a few degrees in flight, adjust it the few degrees while on the ground... Realistically, I never touch mine. The mechanical gauge gets adjusted for being level & the angle for parallax... based on the pilot’s sitting height... only one pilot flys my plane, so this parallax never gets adjusted... Digital displays have no parallax issues... Fun stuff! Best regards, -a- The G5 installation manual includes a procedure to adjust the pitch and roll to level flight. It measures the bank angle and pitch angle as the plane sits on the ground. You then do some calculations and set an offset for each parameter so that the ADI will show wings level and level flight at cruise. 2 Quote
0TreeLemur Posted January 29, 2019 Report Posted January 29, 2019 Think about this- in the case of a regular ol' attitude gyro, you don't adjust the horizon either. You adjust how you view the relationship between the dot that represents your view in level flight. Since as -a- says there is no parallax with a glass display, there is nothing to adjust. Quote
ragedracer1977 Posted January 29, 2019 Author Report Posted January 29, 2019 18 minutes ago, Bob - S50 said: The G5 installation manual includes a procedure to adjust the pitch and roll to level flight. It measures the bank angle and pitch angle as the plane sits on the ground. You then do some calculations and set an offset for each parameter so that the ADI will show wings level and level flight at cruise. Right, but there isn't one pitch attitude for level flight. With glass, you're "stuck" with level attitude, not pitch. Right? Quote
0TreeLemur Posted January 29, 2019 Report Posted January 29, 2019 Just now, ragedracer1977 said: Right, but there isn't one pitch attitude for level flight. With glass, you're "stuck" with level attitude, not pitch. Right? With a standard attitude gyro you can adjust for the effects of angle of attack and panel angle by adjusting the height of the dot. You can't with glass AI. You don't want to try and cruise level with the target on the horizon. It will necessarily be above the horizon 2-5 degrees. 1 Quote
Steve W Posted January 29, 2019 Report Posted January 29, 2019 My new backup RC Allen Digital AI has a button press you can use to set the horizon to level. It was an option when I purchased it, figured since it didn't cost any more there was no reason not to get the feature. Quote
Jim Peace Posted January 29, 2019 Report Posted January 29, 2019 11 hours ago, ragedracer1977 said: My CFII really drilled into me resetting the horizon once in cruise, this is gonna take a while to get used to. This is wrong on so many levels......he/she needs a talking to and it shows that they have a lack in understanding of what is going on. You do not need the horizon to be level when in cruise....what you need to know is your true pitch attitude in relation to the horizon during every phase of flight. 3 Quote
bradp Posted January 29, 2019 Report Posted January 29, 2019 CFI was wrong. The only reason to have the horizon adjustment is for parallex error correction. I believe some of the old school gyro planes like first generation citations had some visual alignment balls that you’d use to adjust you relative to the gyro and view out the window to correct the parallex. Someone who’s flow an old citation or classic airliner would be best to chime in. Your pitch is your pitch. Thought experiment: Remember the pitch plus power equals performance mantra. Lift is proportional to velocity square. So going fast enough you could assume a flat or slight negative AoA and your nose would be a degree or two down and you’d still be in level flight. Slow flight is the opposite. Even more so in the Mooney with flaps up. You’re pretty nose up and you’re in level flight. I’m recalling being on a 747 to Tokyo back when and having to walk uphill to get to the bar in level flight. I was sitting in the way back with a bunch of service members and the flight attendants gave everyone free access to the galley. I don’t recall much after that. Quote
N201MKTurbo Posted January 29, 2019 Report Posted January 29, 2019 I’m sure the G5 has a gravity sensor that knows where down is. It should slowly correct its down reference just like the erecting mechanism in an iron gyro. The G5 also knows your 3D vector while you are moving, it can assume that that vector is on average pointing at the horizon. Considering that the horizon is orthagional to down, it should always align to the correct horizon. It has a lot of information on where the horizon is. Quote
bradp Posted January 29, 2019 Report Posted January 29, 2019 Oh and one other thing - an early version of the certified PFD and the experimental versions do have a pitch offset that is adjustable in flight. It was on my PFD on the initial sw version I had it available. It was just as easy to accidentally adjust it in flight (and you’d have to remember where it was or go back to the offset that was recorded in the initial calibration) that I can very easily see why they locked it out in the later versions. Quote
Cruiser Posted January 29, 2019 Report Posted January 29, 2019 AHRS measure the change and acceleration of the unit to calculate the three axis position relative to the "null" or static position. This is set during the calibration process at installation. The AHRS unit is mounted during installation within a few degrees of level. Some have software adjustments to shift the display a few degrees so the unit will show straight and level flight on the indicator. Quote
ragedracer1977 Posted January 29, 2019 Author Report Posted January 29, 2019 So, my CFII had me center the horizon bar on the ground, then correct it in flight. Looks that was always wrong. And thanks to this thread, I now understand why. And it makes sense! Quote
aviatoreb Posted January 29, 2019 Report Posted January 29, 2019 Why isn't there a "G6" (or maybe a G5b) that is the same thing but with better software that shows SVT instead of a boring colored background. My phone can do it so why can't a specialized piece of equipment like this? Quote
Bryan Posted January 29, 2019 Report Posted January 29, 2019 1 minute ago, aviatoreb said: Why isn't there a "G6" (or maybe a G5b) that is the same thing but with better software that shows SVT instead of a boring colored background. My phone can do it so why can't a specialized piece of equipment like this? $2,249 I am sure they will come out with an add-on for $900 in the future. Quote
aviatoreb Posted January 29, 2019 Report Posted January 29, 2019 8 minutes ago, Bryan said: $2,249 I am sure they will come out with an add-on for $900 in the future. I bet - I figure it will either be a simple software update (priced at $900) or maybe a new chip to stick in the unit (priced at 2x $900) or maybe it will be a swappable whole new head unit (priced at 4x $900). I will be shocked if it does not bubble up relatively soon. Quote
ArtVandelay Posted January 29, 2019 Report Posted January 29, 2019 Why isn't there a "G6" (or maybe a G5b) that is the same thing but with better software that shows SVT instead of a boring colored background. My phone can do it so why can't a specialized piece of equipment like this? Maybe because these are aviation instruments designed for navigation (clean interface), not an entertainment system?Tom Quote
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