Autopilot functionality

I was wondering what does the autopilot use for reference to control pitch and roll. Is it using the magnetometer or does it have rate gyros? what would be the pros and cons of each? I don't know if it makes any difference but I am curious.

The EFIS/One has inside it a complete AHRS (Attitude and Heading Reference System) which is a solid-state gyro, a digital version of your attitude indicator and turn and bank indicator. This is what we use for the attitude indicator on the display, and also how we control the attitude with the autopilot. It is much more accurate than a "mechanical spinning mass" gyro and is not susceptible to the errors that spinning gyros are, like precession and tumbling.

Greg- Im planning trips for next spring to the islands....The current map contains United States with high resolution terrain. Does that include the Bahamas and Caribbean? If not when can we expect to see it?

It's available now as part of the worldwide subscription.

I have been looking at different AP's and comparing features. The AP by Tru-Trak advertises a couple of features that I was wondering if BMA has. In particular it has something called "true control wheel steering". It allows you to point the airplane in a direction and it will hold it and the altitude and also level the wings (if you were in a bank at the time AP was selected). I have been thru the guided tour for E1 and it didn't mention this or if the wings have to near level before engaging the AP. How does E1 compare to tru-trak?

Tony,
The Tru-Trak autopilot is certainly a good one, proven in the field and works very well. The BMA autopilot is different in the way we fly the airplane. Most low-cost autopilots are rate-based, meaning that they operate in one dimension at a time. If you're flying a heading of 360 and wish to turn right to 090, a rate-based autopilot will look for a specific rate of turn, like 2' per second. It will bank the airplane to the right until it sees 2' per second. By the time 2' per second is seen, the airplane has exceeded the amount of bank required to make 2' per second because of adverse yaw and instrument lag. So the airplane tends to oscillate somewhat until it settles into the proper amount of bank for a 2' turn. (This is why rate-based autopilots are usually limited to 20' or so of bank.) The same thing happens on rollout. The rate-based autopilot does not know how to anticipate a heading, and so rolls out when the desired heading is reached. But by the time rollout is complete the heading has been passed and so the aircraft must be banked the opposite direction, and so it oscillates until it settles onto the desired heading.
The BMA Autopilot has the luxury of being connected to a complete AHRS, so it knows exactly the attitude of the airplane at all times, in all 3 dimensions. So when you turn your heading bug from 360 to 090, EFIS/One (or EFIS/Lite!) knows exactly how much bank to command in order to achieve the desired rate of turn, and there is no oscillation. The BMA autopilot knows where it is in space because of the GPS, and so it can fly a precise course through 3-dimensional space. We have also built in features like not allowing the pilot to set a rate of climb that will slow the airplane below Vx. With the altitude pre-select and vertical navigation modes there is no reason to include things like the "true control wheel steering" because we have much more control over the airplane.
The wings do not have to be level before engaging the BMA autopilot, because, again, we know the exact attitude of the airplane at all times. I don't know if we've flight tested things like engaging while inverted, that might be fun to try!

When will it ship? One of the things holding me back is not knowing when it will be "live" (beg pardon if I've missed something)

Now that is cool! Thanks!

I’ll just take this opportunity to give everyone an update on the autopilot stuff. We've been shipping autopilot servos for over a year. There are three versions of the autopilot servos. They are all the same on the inside. The housings are the only things that have changed due to our response to your ideas and comments. The controllers have been shipping since August. We have about 90 people waiting for autopilot controllers, so we're trying to speed up the manufacturing process. The recent move to Colorado Springs, and the addition of several new assembly technicians, will allow us to step up the assembly process. We should be completely caught up on all autopilot shipments by the end of the year.

The autopilot software is currently in final phase testing. This is the reason for the delay in releasing version 2.15. We’ve been holding up on sending out terrain and airspace updates because version 2.15 is so close we want to ship it out all together. I don’t know yet exactly when 2.15 will be released, we’re shooting for the end of this month (October). Watch this website for updates on this.

I know that some of you have been waiting for your autopilot hardware for a long time and your patience is very much appreciated. I hope you’ll find that it was worth the wait! And, as always, if you have any other questions, you can write me by clicking on my name next to this post, or call me at 1-866-FLY-EFIS.

Barry