iFly GPS Forum

"Jim," just to be silly I tried the current version of Garmin Pilot (iPhone Xs Max) in flight yesterday. Here it is showing the glide ring skewed by a right crosswind of about 25 kts (wind from about 310, I think):

The basic size of the glide ring is determined by the aircraft performance data that the user typed in. But that's modified by groundspeed and wind and blah blah. Here's a bit of what the manual says about wind:

Enabling Shift Glide Ring for Wind will factor in local wind conditions when calculating the Glide Range Ring shape. Note the Glide Range Ring uses the most recent weather data, which may be outdated if Garmin Pilot does not have access to real time weather data over Wi-Fi or with outboard hardware such as a GDL 39.

(Garmin Pilot for iOS, page 50.)

So it seems that Garmin Pilot uses reported wind aloft data to shift the ring. And it was getting wind data somehow--maybe via the cell network or possibly from the ADS-B router that the iPhone was connected to for iFly's use.

The white rings around Ownship are optional; I turned them on for this experiment. They and the glide range ring together may suggest something erroneous about my SeaRey's glide ratio--which I know to be at least 8:1 and probably about 9:1.  I probably was too conservative in entering the performance specs about 10 years ago. Anyhow, yesterday I was tooting along at about 80 knots IAS, I think, and Garmin Pilot said I was at 2500 feet MSL over flatland close to sea level, near the Chesapeake Bay. So the various rings suggest a glide roughly 0.5 sm down to 2 nm horizontal--that is, 2500 ft and 12000 feet, or in the neighbornood of 5:1. Not right, but probably not Garmn's fault.

I don't remember what the goofy circle-thing at the bottom of the screenshot indicated. 

But I DO know that I dislike Garmin Pilot more with every update. I can no longer remember--or figure out!--how to make it create a flight plan, find a user waypoint, or do anything else that isn't on the map screen. Yes, there's a 592 page online manual in an 82.3 MB pdf that I downloaded just for the glide range dope. No, I won't print it out to carry in an airplane; and no, I wouldn't read it even if I did.

I'd much rather go flying with iFly for company.

What Pilot does is apply the wind data to your glide ratio and best glide speed entries to produce a glide ring skewed to account for wind, such as the one in my screenshot. (Pilot will also account for terrain if you pay Garmin extra for the terrain data it probably gets free--another reason I don't like Garmin.)

I use the D10A's wind arrow all the time in my seaplane. It's a great help in figuring out the wind direction when landing on water. (You can often see wind streaks and wind shadows on the water, but can't tell which end the wind is from.) 

Dynon requires not only the GPS groundspeed and track, but the OAT, too. The OAT is to correct for variations in air density related to air temp and altitude. That's good if you want to know the wind aloft for accurate navigation, but unnecessary when you're just trying to find the wind direction for a water landing--and therefore it's a big PIA if your OAT sensor dies or you don't have one. Yes, you can enter a number manually, but finding the correct D10A menu for that is an even greater PIA.

However, for iFly and other GPS's, that kind of accuracy might not be necessary, even for navigation, and certainly not for water landings. So I'd think that iFly could add some kind of wind direction and velocity approximation instrument without much trouble. Yes? I'd sure like it, and I'm sure other seaplane pilots would, too.

Here's the wind arrow (red oval) and the 740 complaining about something else. (Part of a video frame--sorry--but the best I can find fast today.)