PDA

View Full Version : TruTrak ADI


Ron
02-26-2008, 05:09 PM
For those who have gone before, for a simple VFR panel, is the TruTrak ADI a suitable substitute for a standard DC Turn Coordinator. Noting it also has a DG. I'm wondering how reliable that feature is also...
Thanks to all
Ron
9A Panel

n5lp
02-26-2008, 05:20 PM
For those who have gone before, for a simple VFR panel, is the TruTrak ADI a suitable substitute for a standard DC Turn Coordinator. Noting it also has a DG. I'm wondering how reliable that feature is also...
Thanks to all
Ron
9A PanelI think the TruTrak ADI is a fine instrument and in limited use I found that it is easy to fly normal IFR with it. It is easier to fly with than a turn coordinator and it shows more information. It must be pointed out, however, that it does not have a DG (Directional Gyro). It does show GPS ground track which is not what ATC uses for vectors at present. They use headings.

whirlpool
02-26-2008, 05:28 PM
best bang for buck!! (in my opinion) when you want to upgrade they will give full price credit on new unit!
flying one in my 8A !!

Tom Schad
02-26-2008, 10:47 PM
I have an ADI in my RV-8, and it works great. Mine has the internal GPS which means it only takes a couple of wires to hook up. No interface with the GPS to wire up that way. Also, it means the Tru Trak autopilot, navigatin and ADI are not all linked to the same GPS. The one limiting factor that I see is that the heading portion is easy to out turn, unlike a DG. If you are turning to headings this needs to be taken into account. Otherwise, it is a great unit, and I highly recommend it. Lots of bang for the buck.

John_RV4
02-27-2008, 07:53 AM
The one limiting factor that I see is that the heading portion is easy to out turn

Yes, if you're flying north and you rack it around in a 4G turn to to roll out east, your normal/DG lead out of the turn won't work well. When you roll the plane level at 090, the gps course will continue to turn. You can find yourself flying 096 or so after you level. It works well with standard rate turns though.

Overall, I also like it very much. In light turbulence it responds faster than the pitot static instruments and you can smooth out those little altitude excursions before your altimeter is any wiser :-). In addition, since I don't have a VSI, I like being able to set up my descent by just pushing to one of the little ladder bars and retrimming.

John

Louise Hose
02-27-2008, 07:29 PM
Not much more to say beyond that. I did have a problem develop after about a year and they sent me a new one before the failing one even reached them. I liked it and the exchange credit policy so much that I recently upgraded to the two-axis autopilot version. So far, it's also great but I haven't put many hours on it yet.

tacaruth
02-28-2008, 07:31 PM
Ron,

You asked "is the TruTrak ADI a suitable substitute for a standard DC Turn Coordinator." In reality, the ADI is not a substitute for a turn coordinator. A turn coordinator displays rate of turn. The ADI will show bank angle. These are two different things. That being said, I hope the ADI will be a good attitude indicator as I am installing one this weekend.

Tom
RV-7A N175TJ Flying

szicree
02-28-2008, 08:19 PM
A turn coordinator displays rate of turn. The ADI will show bank angle.

Not true, I'm afraid. The ADI display looks like bank angle, but the instrument is detecting yaw, not bank.

DGlaeser
02-29-2008, 07:36 AM
Not true, I'm afraid. The ADI display looks like bank angle, but the instrument is detecting yaw, not bank.
Hmmm - the TruTrak info says 'Bank Angle is instantaneous gyro data', and when I powered mine up in my hand it showed bank, not yaw.

bsacks05
02-29-2008, 07:50 AM
Does it do both? It does detect yaw because taxiing on the ground and making turns will show a roll indication when there is no roll happening, only yaw. I read something from Trutrack that it happens because the electronic gyro is not the same as the standard vaccum gyro in its operation and response.

DGlaeser
02-29-2008, 08:44 AM
Does it do both? It does detect yaw because taxiing on the ground and making turns will show a roll indication when there is no roll happening, only yaw. I read something from Trutrack that it happens because the electronic gyro is not the same as the standard vaccum gyro in its operation and response.
Also, the exact orientation of the gyro is important (that's the design difference between a T&B and a TC). Since our RV panels are tilted, I'm not surprised it would react a bit in yaw just 'cause of that.

szicree
02-29-2008, 10:21 AM
Guys,

It's got nothing to do with panel tilt, the Trutrak ADI is NOT an attitude indicator. It's a cool instrument, but it detects rate of turn and displays it as bank angle. It also combines pitching rate and vertical speed and displays it as pitch angle.

Msletten
02-29-2008, 10:36 AM
Guys,

It's got nothing to do with panel tilt, the Trutrak ADI is NOT an attitude indicator. It's a cool instrument, but it detects rate of turn and displays it as bank angle. It also combines pitching rate and vertical speed and displays it as pitch angle.

Directly from the TruTrak ADI User Manual:

"The bank angle display is driven in a manner similar to that used in the pictorial turn and bank. The only difference is that in this instrument the display shows bank angle instead of turn rate."

Regards,

Mark

szicree
02-29-2008, 12:41 PM
I think the water is getting kinda muddy here. The instrument display LOOKS like bank angle, but the fact is that thing has NO IDEA what your bank angle is. It detects acceleration around the YAW axis and PRESENTS it as bank angle. If you don't believe, take one in your hand, power it up, and bank it from side to side; it'll show wings level.

Correction: It detects accelerations in both axis and displays them as bank, regardless of the planes actual attitude. If you're holding a fixed bank angle and not turning (slip, for example) it'll show wings level.

tacaruth
02-29-2008, 02:28 PM
I called and asked Trutrak about this again. According to Trutrak, the ADI shows bank angle. Again, according to them, if you hold the unit in your hand and roll it back and forth, the background will rotate, attempting to stay level with the floor. Again, according to Turtrak, their Pictorial T&B instrument is different, it shows rate of turn.

Again, this is what they said today. I hope to answer this for myself this weekend.

Tom

Ron
02-29-2008, 04:22 PM
Thanks for all the input. I'm glad it turned into this type of discussion. And, please Tom, follow through and let us know your results..I'm still trying to decide how to outfit the panel on a budget..
Tks'
Ron

szicree
02-29-2008, 06:56 PM
I called and asked Trutrak about this again. According to Trutrak, the ADI shows bank angle. Again, according to them, if you hold the unit in your hand and roll it back and forth, the background will rotate, attempting to stay level with the floor. Again, according to Turtrak, their Pictorial T&B instrument is different, it shows rate of turn.

Again, this is what they said today. I hope to answer this for myself this weekend.

Tom

I'd like to slightly ammend my previous post. I just went out to the garage and checked this out first hand. Here's what it does: As you roll the instrument left, it displays a left bank. However, if you stop rolling and leave it in a banked position, the display will roll back to wings level. Additionally, if you yaw to the left, it will indicate a left bank, but only while you are actually turning. As soon as you stop moving, the display returns to wings level. In fact, you can lay this thing on its side and, after initially showing a bank, it will move back to a wings level display. Results are similar for pitch. Finally, I found that if I roll it slowly and smoothly, I can get the display to remain wings level the whole time.

Brantel
03-01-2008, 06:08 AM
I'd like to slightly ammend my previous post. I just went out to the garage and checked this out first hand. Here's what it does: As you roll the instrument left, it displays a left bank. However, if you stop rolling and leave it in a banked position, the display will roll back to wings level. Additionally, if you yaw to the left, it will indicate a left bank, but only while you are actually turning. As soon as you stop moving, the display returns to wings level. In fact, you can lay this thing on its side and, after initially showing a bank, it will move back to a wings level display. Results are similar for pitch. Finally, I found that if I roll it slowly and smoothly, I can get the display to remain wings level the whole time.


All of which will never happen in real life while in the air unless you are flying knife edge or similar. Pick up a normal TC and do some of the same test handheld and you will see similar indications that are different from the normal while you are flying. In the air, this unit has proven itself to work just fine.

szicree
03-01-2008, 10:38 AM
In the air, this unit has proven itself to work just fine.

I agree completely, and that's why I have one. I am in no way badmouthing the ADI as an instrument, I'm simply saying that it is definitely not an attitude indicator.

bsacks05
03-01-2008, 04:23 PM
During the 224 n.m. flight home from the Twelve Oaks fly-in today in Fl. I focused more of my panel attention on my Trutrack ADI. I usually don't pay much attention to it, but that little sucker is very accurate in pitch and roll (you'd think after 200hrs I would have noticed already) and my flying seem to get more precise as well. I had an easier time holding heading and altitude (no A/P). I think I'll be paying more attention to it in the future to see if my flying really does improve.
Yawing still shows a bank indication in the air as well as on the ground. Didn't try holding the yaw to see if it stabilized, however.

tacaruth
03-01-2008, 07:26 PM
I installed my Trutrak ADI today. As Steve has said, the unit does not display bank angle. When the unit is tipped, it shows bank angle for a couple of seconds but then returns to a level display. This is a direct contradiction to what the tech support people at Trutrak said would happen. From their website, "Bank angle is instantaneous gyro data." From what has been experienced by Steve, myself and others, this does not seem to be the case. You would think they would know their own product. Maybe if Jim Younkin, CEO of Trutrak hears about this, he would be able to explain. From what I hear, it should still be a good display, just not what is advertised/explained. I'm looking forward to some good weather to try it out in flight.

Tom
RV-7A, N175TJ Flying

tacaruth
03-01-2008, 07:26 PM
duplicate post

n5lp
03-01-2008, 08:21 PM
I installed my Trutrak ADI today. As Steve has said, the unit does not display bank angle. When the unit is tipped, it shows bank angle for a couple of seconds but then returns to a level display. This is a direct contradiction to what the tech support people at Trutrak said would happen. From their website, "Bank angle is instantaneous gyro data."...Trutrak along with many other companies do not tell you exactly what the instrument does or how it does it. As others have said it is not an attitude indicator and is not advertised as such. It does not show pitch and probably doesn't show actual bank angle, and certainly doesn't show it past certain limits.

If you just kind of forget all that and fly it, in the airplane, you will find that it is very easy to fly without outside reference, solely by this instrument. I think it may be easier to fly with than an attitude indicator, at least in normal flight. For sure, I would way rather have this as a backup than a turn coordinator. Personally, I still would want an attitude indicator in the panel for IMC flight.

tacaruth
03-04-2008, 03:09 PM
Hi All,

Here is a reply from Trutrak about the question of what is displayed.

After reading your message, I believe you may have been misinformed. The gyros in the ADI are rate gyros. They sense only rate of change. When you describe tipping the unit, you momentarily cause a rate change in the gyro. After you leave it on its side, it no longer senses a rate of change, therefore the display returns to level. Think about that motion in an aircraft however, if you put the ADI on it's side, you are obviously in a banked turn. This causes a constant azimuth and roll rate change which would be displayed on the ADI as the angle of bank. I hope this helps you to understand how the ADI works, please let me know if you have any further questions. Thanks!

Lucas Massengale
Technical Support
TruTrak Flight Systems
479-751-0250
866-878-8725
www.trutrakap.com

Jamie
03-04-2008, 03:24 PM
So if you're in a slip, the airplane is banked but no turn is taking place so the ADI will indicate wings level?

szicree
03-04-2008, 04:46 PM
That's exactly right. However, there is a ball at the bottom of the instrument that would tell you the truth.

the_other_dougreeves
03-04-2008, 04:51 PM
So if you're in a slip, the airplane is banked but no turn is taking place so the ADI will indicate wings level?
Yes, I think so, but remember that the ADI has a ball too, and that will indicate a slip. I will go out and confirm this with our ADI pilot this week and report back.

TODR

PS - The ADI and ADI Pilot I/II are sufficient enough of a horizon reference for the LSA night standard - we are approved for NVFR in our airplane with the ADI Pilot II as a horizon reference. And yes, before I get any questions / flames, Sport Pilots cannot fly at night, but LSA can by flown at night by PP or better, if properly equipped.

jbkayaker
03-04-2008, 05:20 PM
Check out a Trio you might like it better than TruTrak. I replaced the TruTrak in my RV6A with a Trio EZ Pilot wing leveler and then added an independent altitude hold from the same outfit. Best avionics move I ever made. Even in light turbulence it holds course within a few degrees and altitude within about 40 feet. And it will function as a turn and bank indicator with an increasing number of vertical bars indicating a faster turn rate.

AltonD
03-04-2008, 07:13 PM
This is good information. I was going to install a 2 1/4 ADI for backup attitude. From reading this thread, I have come to the conclusion that I cannot do a timed turn with the ADI.

Any suggestions for a 2 1/4" turn coordinator? I alreayd have the hole cut in my panel.

n5lp
03-04-2008, 07:40 PM
Trutrak along with many other companies do not tell you exactly what the instrument does or how it does it. As others have said it is not an attitude indicator and is not advertised as such...I started feeling uncertain about this statement I made so went to the Trutrak site and downloaded the manual (I am not an owner). They do refer to the instrument as an artificial horizon there and I would quibble with that.

I still think it is an easy instrument to fly with.

TrutrakTech
03-28-2008, 03:49 PM
That's exactly right. However, there is a ball at the bottom of the instrument that would tell you the truth.

This is correct.

My reply to Tom was a hair off, you would not have a constant roll rate input. My apologies for the misinformation there, I get in a hurry sometimes.

The ADI indicates bank angle, not turn rate. We use software to compute the bank angle from the gyro output. Our Pictorial Turn & Bank indicates turn rate, but that info is also computed through software, not direct gyro output. It detects both roll and yaw rate changes as well, not just one or the other. I hope this helps. Thanks!