Flight path marker stability

[skysailor]

I have seen several videos of the Skyview in motion from both Dynon and a couple of YouTubes. I have a few questions. What is the diameter of the HSI on the ten inch screen at full, half and three mode displays? What is the size of the HSI on the D-180/D-100? I feel confidant the HSI is usable on the legacy units but am not sure of the size on the Skyviews.

On the videos I have seen there is what would have been a Flight Path Marker when I flew jets with Heads Up Displays off the boats. If this is a FPM it seems very unstable in all but one configuration. There is one video showing the Skyview with the FPM and flight director bars. This is the only video I have seen without synthetic vision. The FPM and FD bars are locked together and are centered on the attitude zero reference. My question relates to this. If I turn the synthetic vision off, will the FPM stabilize verses drifting from side to side? Would you please consider a short video of the Skyview without SV? If would be great if it could show PFD/EMS to compare to the D-180. It would also be beneficial to include PFD/MAP and even the 3 screen all without SV.

I think the HSI portion may be more usable without SV and need to know this. While I think I might value the map, I do not plan to use SV and would like to be able to see the system run without it. Thanks!

 

[dynonsupport]

The HSI on a D100 is 1.75" in diameter. It's 1.80" on a 10" SkyView with 100% or 50% sized PFD's and 1.66" on the 40% sized PFD.

Nothing changes on the system without SV except the background goes to blue over brown. There are no other elements that change behavior. The video you saw without SynVis was probably taken without a GPS feed, which is why SynVis was off and the FPM didn't move.

We don't have a flight director today. You can't have a flight director until you have an autopilot. We have a horizon pointer, which might eventually have flight director bars on top of it.

The FPM is unstable in a turn, and we might spend some time tweaking this in the future, but it's pretty common with FPMs. The horizontal part is GPS track, which always has some lag. The vertical part is based partially on GPS vertical speed. It works well in a controlled descent and shows you wind error and where you will touch down. But GPS is inherently laggy in dynamic situations and it takes non-trivial work to get rid of that, which we haven't spent time on yet. Not even sure how much we can get rid of it, since GPS is our only good reference for what is occurring to the plane with reference to the earth, not the air mass.

 

[DrewSwenson]

Just have to be careful with the fpm dependence on gps alt/vsi. BM did this and the fpm could be very confusing showing climbing motion (fpm above the horizon) with a negative vsi---or vice versa. As long as the vsi corresponds with the fpm, all is well.

Also many mil aircraft have the ability to cage the fpm marker to vert motion only.

Not sure that I understand why I can't get fd cues without an autopilot.

 

[skysailor]

Thanks for the answer Support. It certainly looks like the sizes will be compatible to the legacy products and as such should be quite usable for instrument approach work.

Can I turn off the FPM leaving just the attitude display? If so, will the center of the attitude display be a "pipper" (dot)? I find the wandering of the FPM quite distracting.

 

[dynonsupport]

In order to get a flight director, you need to tell the system where you want to go. "I want to go to 4900 feet." "I want to turn to 328 degrees." "I want to intercept the localizer".

Without a way to set this up, you have no flight director, and the way you set this up is always the AP. Look at a G1000, a Boeing or an Airbus. You turn the FD on/off on the AP panel because a FD is a subeset of the AP.

More than that, it is not just another display of the HSI. It requires AP algorithms to figure out how much pitch and roll to show you in order for you to fly on your requested path. If we don't know we want the airplane pitched 10 degrees and rolled 21 degrees in order to go where you want it, we can't show it to you.

We don't have UI in the product to turn the FPM off right now, but we can send you a file to turn it off. It will not have a dot in the middle if you do this, you will use the point where the two horizon pointers come together.

 

[DrewSwenson]

I think we have a terminology mismatch. Won't the autopilot functions (heading, alt, ILS engage, etc) eventually be part of the main display (as opposed to a separate box) and be available to set regardless of whether you have autopilot servos or not?

You should be able to set the flight director without having actual servos----and the pilot should be able to follow flight director commands manually.

 

[dynonsupport]

Yes, you can have a flight director without physical servos, but you can't have a flight director until we have an AP subsystem in the SkyView. So we won't have a flight director until after SkyView can be an autopiliot. Sounds like we're on the same page.

 

[skysailor]

In that vein, I think he is asking if we will be able to use the flight director without engaging the servos. In other words use the autopilot controls for desired heading/course/altitude/vertical path and have the flight director work even though the servos are not engaged. I understand this will not be possible until the autopilot function is released for Skyview. I would find this valuable as well. It would just be a way for Skyview to say "If I were using the autopilot to fly the airplane this is how I would manuever to satisfy the horizontal and vertical requests you have made." As such, perhaps the flight director could be toggled ON/OFF unless the autopilot is engaged. They would always be displayed with the autopilot engaged.

 

[dynonsupport]

Yes, we consider that the definition of a flight director, that it can be on without the servos engaged. When we have it, you will be able to enable it independent of engaging the servos.