[B25Flyer]

I flew the aerobatic test flight on a new RV-7 tonight with 2 Advanced Flight screens. They did not like acro. The pitch, roll, and heading, were way off and never recovered during the 10 to 15 minutes that I flew. They never displayed Red X's either...

What are others experience with Advanced Flight boxes? Is this common or does this unit need some attention?

Initially it was nearly 90 degrees off in roll and maybe 30 degrees in Pitch. The heading was about 180 off and while it got better, only the roll recovered.

Others?

Tailwinds,

Doug Rozendaal

 

[Ironflight]

I haven't had the chance to fly the AFS EFIS yet Doug, so I can't help you directly - do you know what model/vintage they were? Might help pin it down if they were early models.

I haven't seen a tumble in the GRT's in my plane, or the Dynon's in Louise's in all the hours we've flown them - I'm surprised that any of the popular EFIS units would do this, but it depends on how robust their gyro design is.

Paul

 

[Caveman]

I flew the aerobatic test flight on a new RV-7 tonight with 2 Advanced Flight screens. They did not like acro. The pitch, roll, and heading, were way off and never recovered during the 10 to 15 minutes that I flew. They never displayed Red X's either...

What are others experience with Advanced Flight boxes? Is this common or does this unit need some attention?

Initially it was nearly 90 degrees off in roll and maybe 30 degrees in Pitch. The heading was about 180 off and while it got better, only the roll recovered.

Others?

Tailwinds,

Doug Rozendaal

Doug,
I've only done mild stuff, so take this for what it is worth from a rookie. I've had no problem at all and in fact have been very impressed with the way my 3500 handles aero. For a more experienced view point, this question has been asked on the AFS website support forum:

http://www.advanced-flight-systems.com/forum/viewtopic.php?t=421&highlight=aerobatics

 

[Rainier Lamers]

As with any gyroscopic system, once you exceed the maximum rate of turn that can be measured on any axis, the AHRS becomes quite useless.
I'm not sure of the limitations on the AFS but since they use the Crossbow system it should be about 200 degrees/second, same as our SP-5 which uses the same gyros.
It is quite possible to exceed this rate in an RV-7.
Recovery time depends on the system integration and can be just a few seconds (with a strongly aided system) or it can take a long time. Usualy the better the gyros, the longer it takes as aiding tends to be much reduced. On some systems (like ours) you also have a "quick errect" function that you can apply after the horizon has gone tilt after some violent manouver.

Hope that helps

Rainier
CEO MGL Avionics

I flew the aerobatic test flight on a new RV-7 tonight with 2 Advanced Flight screens. They did not like acro. The pitch, roll, and heading, were way off and never recovered during the 10 to 15 minutes that I flew. They never displayed Red X's either...

What are others experience with Advanced Flight boxes? Is this common or does this unit need some attention?

Initially it was nearly 90 degrees off in roll and maybe 30 degrees in Pitch. The heading was about 180 off and while it got better, only the roll recovered.

Others?

Tailwinds,

Doug Rozendaal

 

[N999BT]

ACRO in RVs and AFS

My observations are along the lines of Rainier's. I can make it tumble, it just takes greater than 200 deg/sec or some rate like that. If you do a fairly slow aileron roll, loop, really smooth cuban 8 etc. it will not tumble. The best way I have found to make it tumble is a vertical roll with more and more rudder in as you go up.

I think way down in the menus is a manual set to get it back to straight and level, but I have never used it. It always comes back at some point.

I do find it interesting that your heading is off, however, since the AFS has a very robust magnetometer. There may be a problem with the magnetometer orientation since it is supposed to be aligned with EFIS in all three axes. I initially installed mine a little bit off compared to the EFIS and it would show a change in heading with a change in pitch. It was very disturbing. But once I got it installed correctly it there have been no problems. I trust it enough to fly approaches in IMC. Just don't do snap rolls after the FAF.

 

[N402RH]

Doug,

Please download and email the data files for the last couple of hours of flight time. We should be able to see what happened from this logged data. The data logs store all of the flight data, engine data and AHRS status. We should be able to see what the roll rate and g-loading was before the problem.
The internal sensors in the AHRS are limited to maneuvers of less than 200 deg/sec and less than 10 G's acceleration in bank, pitch and heading. Over range of a sensor is indicated by a large red X on the display. Over range will start a new initialization cycle of the AHRS and will require 90 seconds of straight and level flight to reinitialize. I have found that doing normal sport RV style aerobatics I do not lose it in my RV-4.

We also have the system in Renny Price?s SU-29

http://hammerheadaerobatics.com/



The AHRS will over-range during his airshow routine. Renny uses our analog instrument page without horizon during the airshow. The EFIS has never had a problem in the SU29 flying between airshows and while doing aerobatics at under 200 deg/sec. Renny?s SU29 has an AF-3500 EFIS and Engine monitor along with a Garmin 430W and is signed off for IFR flight.

Rob Hickman
Advanced Flight Systems

 

[brettt777]

I haven't seen a tumble in the GRT's in my plane, or the Dynon's in Louise's in all the hours we've flown them - I'm surprised that any of the popular EFIS units would do this, but it depends on how robust their gyro design is.

Paul

Your GRT's are in an RV I take it...? And you haven't had any problems with aerobatics at all? This is good to know. Stein told me the GRT's were pretty good units and they are rated high enough for our L-39s in G's and roll rate. I have a guy out in Cali that has two jets with Blue Mountains and of course he hates them and we are trying to decide what to replace them with. I was wondering about GRT's since they are the only reasonably priced unit that is close to the size of a Blue Mountain.

 

[Ironflight]

Your GRT's are in an RV I take it...? And you haven't had any problems with aerobatics at all? This is good to know. Stein told me the GRT's were pretty good units and they are rated high enough for our L-39s in G's and roll rate. I have a guy out in Cali that has two jets with Blue Mountains and of course he hates them and we are trying to decide what to replace them with. I was wondering about GRT's since they are the only reasonably priced unit that is close to the size of a Blue Mountain.

Yes, the GRT's are in my RV-8, and I fly acro almost every day. I've made a few posts about the systems over the years here in the forums - you can search for them. If you have any doubts about the technical capability, Greg at GRT can probably answer your questions, but I can give you a field report that at 1,000 hours, I have yet to have an inflight tumble.

Paul

 

[ao.frog]

No tumbles here either.

I'm flying quite a bit of acro, but never with less than 0 G, (no negative oil-system installed)

The 3500 keeps up ok (never use it for attitude reference during acro though), and after the acro-sequence is completed, (takes 2-10 minutes, depending who is with me), the 3500 can be anything from 5 to 30* off in bank and 0 to 20* off in pitch.

It erects itself in a minute or two with straight and level flight.

I really like the 3500 and I've just passed 100 hrs on the Hobbs and will most probably install another 3500 (or maybe a 4500) in in my second RV-7.

Also I like to add that Rob and his people have been VERY helpful during the installation and testflying phase.
They've been providing GREAT cutomer care!