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Bryan Wood
06-20-2008, 06:16 PM
Any experienced users of the EZ ALT Hold out there? Having just finished the install on one of these systems I'll be going for a ride in the morning to set up and test the thing out.

Questions:

1. When setting up the min. airspeed which effectively noses the thing over when to ambitious of a climb is set up, how did you determine what speed to use? Is seems like if I set it low enough that it will stay engaged for decents/approaches it will not correct itself on climbs until a very steep angle is reached.

2. When setting the max airspeed that the alt hold will stay engaged how did you determine where to set it? I'm thinking of setting it at the yellow on the airspeed indicator, but am wondering what others are doing. What are your thoughts?

3. What setting works well to drive the trim servo correctly.

Thanks,

Sam Buchanan
06-20-2008, 09:03 PM
Any experienced users of the EZ ALT Hold out there? Having just finished the install on one of these systems I'll be going for a ride in the morning to set up and test the thing out.

Questions:

1. When setting up the min. airspeed which effectively noses the thing over when to ambitious of a climb is set up, how did you determine what speed to use? Is seems like if I set it low enough that it will stay engaged for decents/approaches it will not correct itself on climbs until a very steep angle is reached.

2. When setting the max airspeed that the alt hold will stay engaged how did you determine where to set it? I'm thinking of setting it at the yellow on the airspeed indicator, but am wondering what others are doing. What are your thoughts?

3. What setting works well to drive the trim servo correctly.

Thanks,

Bryan,

I've been flying the EZ-Hold since its very early days. You are going to really like your EZ-Hold!

1) I set the min airspeed to 80 kts, (just to address some sort of massive brain fade) but I have never been in a flight environment where this limit has been reached. From cruise you would have to set an outrageous climb rate in order to pull the airspeed down this low. If you are shooting approaches you will generally be using 500 fpm rates and you won't have any reason to hit the 80 knot threshold if you are paying attention to flying the plane.

2) Max airspeed on my unit is set at the bottom of the yellow arc. I usually have to reduce power a little to stay under this threshold when descending at 500fpm. I've considered setting the limit a little higher but am comfortable with it as is. This keeps me from blasting down from altitude and smooth air into turbulence at lower altitudes in the yellow arc.

3) I don't have the auto-trim feature since I use manual elevator trim.

Don't expect to get all the settings nailed on one flight. You will need to live with the system for a few flights and try various settings until you find the limit set that works best for your normal flight scenarios. Don't be surprised if you continue to tweak the settings for some time to come since it is so easy to fine tune the system on the fly.

Enjoy!

n468ac
06-21-2008, 06:00 AM
1. Min airspeed set at 100KTS ... just didn't like to nose so high i can't see anything by sky.

2. Max airspeed set at 171KTS ... during testing the autopilot didn't over shoot 181KTS even at 3000 FPM ... you can always pull the power out if you don't want to go that fast.

3. Don't have.

videobobk
06-21-2008, 01:24 PM
My minimum speed is set at 80 mph (9A) which is a little faster than I think it could be, just to have an airspeed cushion. I set max at yellow line (180 mph.) I don't have trim setting either. BTW, you will want to try all this as Sam says. Very nice system. I do a lot of 400 fpm descents but few climbs on alt hold. How you use it may make a difference in your settings. It will become second nature.

Bob Kelly

Bryan Wood
06-21-2008, 03:37 PM
Thanks for the replies on this. I just got back from trying this thing out and for the most part it is really neat. There are a couple of little things that need addressing or understanding and then addressing. The min and max was easy to set and I did it as suggested by Sam. There is a message that appears sometimes, or somewhat intemittently for clutch slippage. This seems to only happen in climbs or decents in the vertical speed mode. Sometimes I think there is a faint sound of the servo howling behind the baggage bulkhead from slippage. When I heard this the annunciator wasn't showing a slippage message. So in short this could have been imagined. The second issue is hunting or very slight porpoising with the VSI going up and down 200-300 fpm but the alt basically holding it's setting with maybe a +/_ 30 foot deviation. This brought up another issue which is the auto trim which wasn't intuitive on setting a proper speed when the plane is hunting on altitude. So I guess the first order of business is to go back out to the hanger early in the morning again when it is cool and remove the canopy, baggage bulkheads, and seats and dive head first into the tailcone again to tighten the clutch. It seems like chasing the porpoise issue is futile with the clutch slipping slightly. Heck, it could be the cause. :rolleyes:

Best,

Bryan Wood
07-12-2008, 09:47 AM
Alt Hold Update:

While working out the clutch slippage issue mentioned above I went and tightened the clutch to much and broke a gear inside the servo. This is a built in safety feature to guarentee that the pilot can manually take control of the plane if the clutch is locked up. Well, it works as designed. :o With a call to Trio and a confession that I ham fisted an adjustment and broke the gear I was told "No problem."

Trio gave me a choice of receiving a new gear and installing it myself, or shipping the servo to them. We talked a little about the slip message and it was decided to return the servo to them so that they could verify that everything was good inside the clutch. At my request they set the clutch as tight as it could be and not risk gear failure so that if there is more slippage I would know the problem was in my plane, not in the servo. With a quick turn time and return of the servo the flight testing was going on again.

On the next flight there was more clutch slippage, but when the message would appear I would immediately dis-engage the alt hold and found the plane WAY out of trim with dramatic forces needed to hold the stick . So in response the trim was turned all the way down and trimming manually was done to try out the system again. The result was more porpoising. Dang, this was frustrating. The folks at Trio had suggested disconnecting the static port from the alt hold and venting it to the cabin and trying to see if the porpoise went away. So it was disconnected for this flight and when flying along basically level I adjusted the eyeball vent for a little more fresh air and what a ride! The transducer in the Trio really felt it and the ride could be much like a roller coaster with a kid at the controls of the vent so this thing had to be hooked back up. The idea did help however as the manufacturer thought it would so it looked like the fix was running a new static line dedicated to the Trio. Apparently the placement of the ports on my plane is causing some kind of fluctuation that the ultra sensative transducer feels, but the VSI can't even see. Not wanting another hole in the side of my plane the search for another idea was on.

Bring my father in law into the mix now. He is very, very sharp and told me to try the following. So the household "T" fitting that I used to split off of the 1/4" OD static line tubing that Van's provided was disconnected where it went to the autopilot. The brass ferril that slides into the end of the tube was removed and one was installed that I had filled with epoxy and once cured drilled at .040". This idea was to dampen the pressure changes that were occuring at my static ports and off I went for another flight. Bingo, level flight! I'm posting this because I've had people contact me with suggestions of the mount for the servo flexing causing the porpoise which was not the case. If anybody else has this problem it is an easy way to rule out the servo. I was a little concerned that if this idea fixed the porpoise that the dampening would be so great that the autopilot couldn't keep up with the pressure at the static ports on climb or decent effectively making the vertical speed feature useless. This wasn't the case at all so things are looking promising.

With a call to Trio to report the findings they were still concerned about something going on at my static ports. There was optimism however an a suggestion that I do a system restore to get the factory settings back in the autopilot and going up again. With specific directions on setup in flight now that the porpoise was basically gone the flight was made. After setup the plane flys very good level, and in vertical modes, but the altitude intercepts are not right.

So with a vertical speed setting of say 800 fpm and an intercept altitude the following is happening. As designed, before the cruise alt is intercepted the climb reduces to 200 fpm for a smooth intercept. Then after leveling off the plane works its way into a decent at the 800fpm rate that is set up from the climb. Disengaging the autopilot again the plane is way out of trim. It is a little alarming so another call to Trio. Again, the static port is looking like the problem. The theory is that there is a pressure change at the port after leveling off and the autopilot is trying to seek the cruise altitudes pressure as felt by the erratic static ports. Well out of clever ideas the plane was put away while life continues.

Today I'm thinking of taping off one of the static ports and trying the intercepts again, and then reversing. I'm wondering if the air spiraling off the prop could be causing the probem as it hits the side of the plane. The idea of putting another static port in is bothering me. Where would I put it to make it better? Then there is the lack of places to run the line thru the spar and another hole isn't a good idea.

So, any ideas out there? The one constant in this is Trio's customer service. There is no sign in their voices that I'm being a pain in their side when they receive another call from me. They are sure that running a new static line will fix my problem but they are being very reasonable with my experimenting. What a great bunch of folks to work with me as I don't follow the tradional path on this. It has been volunteered to ship me another electronic module so it can be ruled out even though they are sure the problem isn't that. A company that allows us to be homebuilders without arguing with our ideas is special indeed. I'm determined to put a bandaid on the problem. There has to be a way. :cool: I can see that when my airplane issue is fixed this thing is going to be fantastic. Well, off to the airport for another round of flying. Somebody's got to do it.
(If I knew exactly where to put a dedicated port for success I would do it, but ???)

Those of you flying alt holds, did you use the standard placement for your static ports?

Sam Buchanan
07-12-2008, 08:17 PM
Alt Hold Update:

Today I'm thinking of taping off one of the static ports and trying the intercepts again, and then reversing. I'm wondering if the air spiraling off the prop could be causing the probem as it hits the side of the plane. The idea of putting another static port in is bothering me. Where would I put it to make it better? Then there is the lack of places to run the line thru the spar and another hole isn't a good idea.

So, any ideas out there? The one constant in this is Trio's customer service. There is no sign in their voices that I'm being a pain in their side when they receive another call from me. They are sure that running a new static line will fix my problem but they are being very reasonable with my experimenting. What a great bunch of folks to work with me as I don't follow the tradional path on this. It has been volunteered to ship me another electronic module so it can be ruled out even though they are sure the problem isn't that. A company that allows us to be homebuilders without arguing with our ideas is special indeed. I'm determined to put a bandaid on the problem. There has to be a way. :cool: I can see that when my airplane issue is fixed this thing is going to be fantastic. Well, off to the airport for another round of flying. Somebody's got to do it.
(If I knew exactly where to put a dedicated port for success I would do it, but ???)

Those of you flying alt holds, did you use the standard placement for your static ports?

Bryan, I don't have a solution for you but I have never heard of anyone having to install a "dedicated static port" for the autopilot. I really doubt that would fix the problem. Seems if the static system was flaky enough to confuse the AP that you would see errors in your other static instruments.

You keep mentioning the trim being way off when you disengage the system. The trim is where I would be concentrating my troubleshooting. I don't have personal experience with the auto trim option since I use good 'ol manual trim (always works correctly....if the pilot is paying attention!) but if the plane is way out of trim the AP is going to be fighting a challenging battle.

Stay with it, it will no doubt be a minor fix once you find the problem. As you know, the Trio guys are going to hang in there with you. :)

Bryan Wood
07-12-2008, 09:01 PM
After flying today there is some new information which brings up some questions.

1. Taping off the static port on the passenger side and then flying, the plane will climb per setting, level off at the preselected altitude, and it will trim itself. ;)

2. After landing and switching the tape to the pilot side the plane will climb per setting, level off at the preselected altitude and nose over way out of trim. :eek:

3. Landing and switching back the tape to the passenger side the plane leveled off and trimmed correctly again. :rolleyes:


So now the question is, do I need static ports on both sides of the plane? If so why? A reason that I think it does need both is because with the pilot side taped I set the altimeter and the Trio to the field elevation of 160' at Watsonville, CA. When making a left turn during taxi it oriented the plane so that the wind hit the passenger side. I looked at the altimeter and it showed 190' which seems like a reason that both sides are needed to equalize. After doing a few searches on the net is appears that ports on both sides are for side slips which is kind of what I saw during taxi.

On another note, while talking with the father in law about this some more he mentioned that Piper had a separate static port on this Comanche near the instrument panel on the pilot side for the original autopilot. The two static ports for the instruments are in the tail. This has me thinking that I'm chasing something that has been known for decades but forgotten or not passed on to the current generation of flyers.

Any thoughts?

Sam Buchanan
07-13-2008, 06:58 AM
After flying today there is some new information which brings up some questions.

1. Taping off the static port on the passenger side and then flying, the plane will climb per setting, level off at the preselected altitude, and it will trim itself. ;)

2. After landing and switching the tape to the pilot side the plane will climb per setting, level off at the preselected altitude and nose over way out of trim. :eek:

3. Landing and switching back the tape to the passenger side the plane leveled off and trimmed correctly again. :rolleyes:


So now the question is, do I need static ports on both sides of the plane? If so why? A reason that I think it does need both is because with the pilot side taped I set the altimeter and the Trio to the field elevation of 160' at Watsonville, CA. When making a left turn during taxi it oriented the plane so that the wind hit the passenger side. I looked at the altimeter and it showed 190' which seems like a reason that both sides are needed to equalize. After doing a few searches on the net is appears that ports on both sides are for side slips which is kind of what I saw during taxi.

On another note, while talking with the father in law about this some more he mentioned that Piper had a separate static port on this Comanche near the instrument panel on the pilot side for the original autopilot. The two static ports for the instruments are in the tail. This has me thinking that I'm chasing something that has been known for decades but forgotten or not passed on to the current generation of flyers.

Any thoughts?

Guess my thoughts are........this goes to show how much I know about static ports....... ;)

You need to do whatever it takes to make the autopilot work on your plane. This is however, the first time I've ever seen a static port problem effect an AP on an RV in the ten years I've been messing with this stuff. I am assuming of course that your ports are located and fabricated according to the Vans plans.

We learn as we go.

Bryan Wood
07-13-2008, 08:43 AM
Yes, the static ports are right where the plans call for them to be. I think there were even prepunced holes in the 9 kit where the factory wanted them. I've been bouncing ideas back and forth with another builder that has the same engine and prop setup as me and he is having the same problem. I'm anxious to see if taping the static port helps his also.

The wierd thing about this is how the altimeter and vsi can't see any fluctuations at the static ports. I guess the transducer in the Trio is extremely sensitive and nothing gets past it.

Here is a little speculation that has no basis in fact. This just has me wondering why mine, and not all of them?

I'm thinking that 9's flying with a Hartzell are going to have this problem if they ever get an altitude hold system. Or it could simply be our engines in the two planes that I'm referring to in this response, mine and the other one. We both have basically the same 0-320 D1A's slightly hot rodded by the same engine shop exactly the same way. Maybe the combination of the engine and prop is causing some kind of prop pulses or something on the side of the plane that others are not seeing. Regardless, of what is causing it, the thing is working really good right now with the static port taped over, so ?????

Sam, the lack of input from others on this thread seems to support your observations about how odd this is. Good Lord, I couldn't even get George to offer ideas. He is freakin smart and always has a direction to look for problems. Kahuna, are you by any chance following this thread? It is my understanding that along with Sam you have a lot of time invested in this stuff. Any ideas? What would you guys do at this point? Would you fly with one static port or guess at a neutral location and drill a hole?

Sam, thank you very much for taking the time to help with this.

almarsh
08-30-2014, 09:40 PM
I have had similar issues with clutch slippage error and porpoiseing nose up and down.

First few flights when I disengage alt hold way out of trim, then I level off again retrim
Useing manual trim to level flt. Again set alt hold smooth for about 30 sec. Or so then the
Hunting starts again to a almost out of controll porpoiseing again all this in smooth air.

I did this same thing so many times in a row that I tried to keep up with porposing useing stick
And or manual trim to relevel that I eventually stripped gear.

Talked with trio sent servo back to them, they really go all out for customer service
Fixed servo and shipped at no charge. Reinstalled for a few flights it seemed to of fixed
The problem. But wouldn't you know the issue has returned again with clutch slip error
So I've kinda have quit using it for awhile thought I had something else wrong.

Saw your post so kinda following what you've tried.