R

RV_7A

Well Known Member
Anyone using the ADI as opposed to a Artificial Horizon and if so what do they think about it? I was considering getting one instead of an AH.

-Jeff

ADI235x231.png
 
I have one on order, but can't say how it works yet. From reports of others in our local group that have them, they say you will be very impressed with the ability to pin the altitude. So you are in a climb, push the nose over till the dot is on the horizon and you will be level. It uses VSI info as part of the equation so it perfectly levels you out with little if any overshoot etc.

They used it in all conditions in a 6A and reported it worked fine, handled upsets, etc.

I'll report more once mine is installed and working.
 
I'm planning on installing one in the 2-1/4" format when it is available.
 
I have my Basic ADI (pictured in your post) installed but not wired or flying yet. It gets heading info from your GPS so you will need a cable for that. You can, but don't have to, hook up a pitot line and preset your stall speed so you get a flashing indication (heading display) when you fall below that speed. There is supposed to be an internal backup battery but it is not yet available. It will give you an additional 4 hours of operating time if you lose external power.
My -9 is sooooo close to being finished, but progress at this point seems so excruciatingly slow. I need to take a couple weeks off from work and family, set up a bed and fridge at the hanger and get it done.
Anyway, I am hopeful that the ADI, as well as everything else in the plane, functions as advertised.
Bruce
N659DB
 
Adi

I have about 5 hours on my ADI Pilot 1 in my RV4. The ADI works great and the AP sure helps on long flights.
Don
 
ADI Pilot II

If you ultimately decide on the ADI, you might consider going with the ADI Pilot II autopilot control head instead of the plain ADI. As of my current panel plan - and you know all that can change :rolleyes: - I am planning to install the ADI Pilot II in my panel. I sent an email to Trutrak asking if I can use the ADI Pilot II in lieu of the ADI and buy the servos whenever I can afford them. Their reply was that it will operate just the same as the ADI without the servos. The price without servos is $1995. Versus $1095 for the ADI, I think it is worth getting for the extra money instead of investing in the ADI and replacing it in the future. I plan to pre-wire so hopefully all I have to do is install the servos and "plug-n-play" whenever I can afford them.
 
From the writeup Bob referenced:

"Finally, if you fly level and slow down until you approach the stall the pitch indicator stays level and then starts to go down as the sink rate increases even though the nose is way up. The only indication on the screen is a flashing "AS" for airspeed."

That doesn't sound so good to me. Imagine an encounter with a strong downdraft- you've got the nose up trying to maintain altitude as the airspeed bleeds off, all the while the ADI is showing nose down? Hope you're in VFR!

Jim
 
Actually, I think it's hard to predict the indication in a situation like the one above. Since the instrument is reading static air and you're moving in a downward moving mass of air, perhaps there is no change in pressure for the device to sense. In any case, if you're VFR it's no issue, and if you're in IMC shouldn't you look at the ASI once in a while?
 
mikehoover said:
If you ultimately decide on the ADI, you might consider going with the ADI Pilot II autopilot control head instead of the plain ADI...
Click to expand...
I think Trutrak still has the policy of letting you upgrade without penalty, as long as they still sell your current unit. That's another option of going ADI to ADI Pilot.
 
I guess I don't see the point of getting an ADI unless you are building a strictly VFR plane. I would not trust it as a primary attitude indicator in IMC, and there are better choices for a backup. Combined with an autopilot I guess it would be alright, as long as you remember it is not really an attitude instrument, and in IMC in a bad situation it could confuse you as much as help you.
 
This is not a pure attitude instrument

Yes, we considered this instrument for an EFIS backup. Then I read the fine print. The company states that the pitch attitude information is, (drum roll) "augmented vertical speed". This feature does not make this instrument a pitch attitude indicator. As one fellow mentioned in a post before this, you could set up a nose high attitude with a little power on at low airpeed (consider the RV stall attitude is 23 degrees) and as your vertical speed would begin to go negative, this instrument would show a nose down indication. Even though your pitch attitude was 20 degrees nose up?!?!?!

We Won't Get Fooled Again! (The Who)

If you are considering this instrument for an IFR backup Artificial Horizon, DON'T! This instrument is slightly better than a turn co-ordinator for attitude and it does give you ground track information, (not heading) but that's about it.

Cheers, Pete
 
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Lots of arm waving....

Interesting discussion.

If the airplane is close to stall and the pitch indication becomes inaccurate, you get the AS warning. At this point, it should be clear that you need to push the stick forward and prevent the imminent stall. I could argue that this is BETTER since you can see the problem right on your AI.

If you are IFR and the bank angle is exceeding 30 deg, you probably don't want this to happen. I don't know of any other instrument that would warn you of this while still giving you plenty of time to avoid the graveyard spiral.

If you are in an unusual attitude, the AI is used to level the wings. I don't think this would be any different with the ADI.

Lastly, when you recover from the unusual attitude, your AI will still be working.

I'm not sold on this unit either. But I see "different" and that seems to scare people.

It somewhat reminds me of when GPS started to become popular. Some people screamed that GPS gives you TRACK not HEADING as if this were some terrible thing and would cause you to fall from the sky. It's different.

John
 
I don't see any problem with using the ADI as a backup to an EFIS. The traditional method for backing up attitude data is vertical speed and turn coordinator. The ADI basically combines these two instruments with a backup battery to boot. As long as you understand what it is...I really don't see the problem.

I do agree though that another EFIS or attitude indicator would obviously make a better back up...but I think the ADI would suffice for a great number of people.
 
Mustang said:
you could set up a nose high attitude with a little power on at low airpeed (consider the RV stall attitude is 23 degrees) and as your vertical speed would begin to go negative, this instrument would show a nose down indication. Even though your pitch attitude was 20 degrees nose up?!?!?!
Click to expand...

I believe this analysis is incorrect. My understanding of this instrument is that in order to indicate a nose up or nose down attitude the plane must first pitch up or down. That is, the device senses pitching rather than pitch itself. Once the device senses (and indicates) this motion, it then uses the vsi data to hold the indication. So, if you began pitching upward while descending, I believe the instrument would actually show no indication once the attitude stabilized. This is how the thing works to the best of my limited understanding. I can state for certain that pulling a vacuum on the static port of my ADI causes no change in indication.

Also, consider the exact same circumstances with a standard IFR instrument setup. You're nearing stall, mushing downward in IMC and staring at the attitude indicator. You're not listening, checking airspeed, vertical speed, or altitude. Assuming all this, you'll think you're climbing. I'm not saying this is better or worse, but the point is that you'll be misreading your situation. I think the bottom line is that no single indicator (yet) is able to give us all the data we need, so we have to scan.

I personally am only intending to use my ADI as a "bacon saver" if I ever unintentionally fly my bare-bones day-VFR fixed-pitch toy into clouds. I also like the idea that it gives me gps heading info and that the Trutrak folks will allow me to update it to an autopilot if I ever get this thing in the air and decide I wanna actually go somewhere.

Wow, talk like this makes me feel like it's actually gonna happen some day and I get all goose-bumpy :D
 
Steve, it's a common practice to cover an instrument when it starts indicating wrong information so it doesn't confuse you with conflicting info... considering how this thing behaves, I'd cover it in IMC... and then.. why have it?

PS. What's up with indicating "level flight" after a while in one attitude, or was it bank? (based on report from matronics)
 
Radomir said:
What's up with indicating "level flight" after a while in one attitude, or was it bank? (based on report from matronics)
Click to expand...

The bank indicator doesn't actually sense bank :confused: , it senses yawing and indicates it as bank. This works fine in normal turning. However, in knife edge flight it would indicate wings level because there is no turning taking place. This is obviously misleading, but what would an attitude gyro say in knife edge? A traditional turn indicator does the same thing: sense yaw -- indicate as bank. All of our instruments require interpretation. I mean, the altimeter spins round and round but that doesn't mean the plane is.

I'm not an IFR pilot and probably won't be, so most of the shortcomings of the ADI don't matter to me. My reason for getting it was to have a cheap, robust device that could pull my fat out of the fire if I screw up, but not fall apart from all the acro I want to do.
 
It's amazing how these threads can take interesting twists and turns - almost like a failing vacumn-driven gyro... :rolleyes:

I haven't flown with the Tru Trak ADI, but I can tell you that my own IFR redundancy scheme is based on their Pictorial Pilot. My redundancy is easy to summarize:

Primary - GRT EFIS
Secondary - Let the Pictorial Pilot fly while I navigate
Tertiary - fly to the Pictorial Pilot's Turn Coordinator display (partial panel)

I went with this scheme before the ADI was available, but I am not sure that I would need that pitch function anyway - oh, that's becasue I also have an Altrack to keep me "on the level". There are many ways to skin the cat.

I'm only guessing here, and that may make this invalid, but I suspect that flying the pitch indication on the ADI is kinda like using the velocity vector indicator for pitch on an EFIS. It is a nearly instantaneous method of determing when you are flying level (put the dot on the horizon), and very effective. But I'd like to fly an ADI before I was certain of this!

Just late night musings....

Paul
 
How do the autopilots work?

After reading through this thread I was wondering about how the autopilots do their thing. Obviously the device can control pitch, but does it do so in response to altitude or attitude data?
 
szicree said:
After reading through this thread I was wondering about how the autopilots do their thing. Obviously the device can control pitch, but does it do so in response to altitude or attitude data?
Click to expand...

Can't speak of any others, but in the case of the Altrak it's altitude data by way of static pressure. You have the option of plugging into the static system or just using ambient pressure from wherever you mount the control module.

Jim
 
Jim Percy said:
Can't speak of any others, but in the case of the Altrak it's altitude data by way of static pressure. You have the option of plugging into the static system or just using ambient pressure from wherever you mount the control module.

Jim
Click to expand...
Partially true Jim - in addition to altitude, as you state, the Altrak also uses pitch (or pitch rate, not sure which), because you can hold the "brain box" in your hand on the ground, pitch it up and down, and watch the servo respond. Just did this test in my install this week.

Paul
 
Just my $0.02:
I've got about 50 hours on my VFR -6A. I need an autopilot and AH. But the AH has got to tell me where the nose is pointing and where the wings are if I can't find the horizon. No matter what the bank angle, airspeed, VSI, etc. (Hoping to never, ever really need it!) I don't think the Tru Trak ADI/autopilot will fit the bill. Too bad, the price is right!
 
If Tru Traks Pilot II can "fly the plane" using auto pilot and has all the data to stay straight and level. Then how come the data it gathers displayed on the ADI is incorrect? It sounds like some of the descriptions written here are saying you could not fly the plane IMC or IFR using the auto pilot. Say auto pilot was engaged, and you encounter a down draft, surely the system would pull nose up on its own, is this to say during this event the ADI would indicate nose down?
 
I was thinking exactly the same thing. If I understand correctly, the ADI presents the exact same data that the autopilot uses. So if that little box (the autopilot) can fly off it, why can't a human?
 
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