I've heard a lot on the AV-30s without an external magnetometer as being not too good. But many say with a magnetometer it improves a lot. But does it get better than a standard vacuum DG? If not and it is not at least better then perhaps I should just get mine overhauled. It would be way cheaper. I'm looking for better data on just how well it maintains accuracy with the magnetometer. Does it also degrade more when maneuvering? But if I could get 5 degrees drift per hour would be superb.A mechanical DG should do better than that, sounds like yours needs an overhaul. My mechanical DG when healthy would drift about 5-10* every 15 mins, depending on how much maneuvering I was doing. Last year the AI needed another overhaul so I replaced both AI & DG with dual AV-30 and removed the vac system entirely. The AV-30 without a magnetometer drifts about the same as the mechanical. The big drawback to the AV-30 in DG mode is when the temperature changes significantly from what it was when the DG aligned itself during startup (example: take off in 50* F air then climb to sub-freezing temps), it drifts so bad it becomes useless.
Due to this temperature issue, I just bought the external magnetometer but haven't yet installed it.
Pitot tube follows Bernoulli's principle of pressure. Pressure is felt across the entire system. It doesn't take much air volume to change the instrument reading so the pressure can be distributed to multiple instruments. I have 3 instruments attached to my pitot/static. They use t-fittings with quick connectors.So I contacted UAvionix and they said with the external magnetometer there is no drift. Zero. (can anyone vouch?) Also asked them if pitot tube sharing causes any loss of airspeed information - they answered 'no'. Also they plan to have a lot of autopilot integration in the future, with tru-trak, trio, s-tec and century. Good stuff to know.
Why would it drift if it’s being constantly corrected?So I contacted UAvionix and they said with the external magnetometer there is no drift. Zero. (can anyone vouch?)
Mine is extremely accurate with the magnetometer. Next to no driftWhich is more accurate- The AV-30C with magnetometer or a refurbished vacuum DG? My current vac DG drifts 20 degrees in a turn. What kind of drift do the AV-30-Cs experience?
We added the magnetometer and that eliminated the annoying drift.So I contacted UAvionix and they said with the external magnetometer there is no drift. Zero. (can anyone vouch?) Also asked them if pitot tube sharing causes any loss of airspeed information - they answered 'no'. Also they plan to have a lot of autopilot integration in the future, with tru-trak, trio, s-tec and century. Good stuff to know.
Which is more accurate- The AV-30C with magnetometer or a refurbished vacuum DG? My current vac DG drifts 20 degrees in a turn. What kind of drift do the AV-30-Cs experience?
You may not quite understand the purpose of a magnetometer. Any installation with one is constantly correcting, so there is no drift unless something is broken. Any DG or HSI with a magnetometer is detecting the magnetic north pole itself, so it should always be spot-on. After all, you don't hear about airline pilots resetting their DGs every 15 minutes - because they have magnetometers too.So I contacted UAvionix and they said with the external magnetometer there is no drift. Zero. (can anyone vouch?).
Good advice. The uAvionix magnetometer is inexpensive so the entire system (vac removal, dual AV-30C) is still significantly less expensive than Garmin. My avionics shop quoted $6k for uAvionix versus $9k for Garmin (both prices all-in). uAvionix is great for VFR only airplanes like mine. But if you're going IFR, the Garmin system is more capable and worth the extra bucks for most people.If you are going to fly IFR, and are going to go to the trouble to install a magnetometer in the wing (typical) anyway, consider getting a G5 or GI275, which are true HSIs that will integrate with your IFR GPS as a primary CDI, and also direct an autopilot.
Indeed. Both quotes I mentioned were for complete vac system removal and dual instruments. I'm sure the prices have gone up over the past year but the ratio between them is probably unchanged (Garmin about 50% more).Fair, for one system.
But if you have a desire to delete the vacuum system you'll need 2, in most cases.
...
Find an A&P to check your work and do the AV-30 install yourself. Really easy.Good advice. The uAvionix magnetometer is inexpensive so the entire system (vac removal, dual AV-30C) is still significantly less expensive than Garmin. My avionics shop quoted $6k for uAvionix versus $9k for Garmin (both prices all-in). uAvionix is great for VFR only airplanes like mine. But if you're going IFR, the Garmin system is more capable and worth the extra bucks for most people.
The install manual will tell you how to trim the IAS.After fixing the heading drift with our AV-30's, now we have an issue with the airspeed being off. I would be ok if it was within a few mph of the old analog airspeed indicator, but it's around 7-9 mph off on the high side. Moreover, at all altitudes the TAS on the display is slower that the indicated. That could be installation error or something is malfunctioning.
I've flown in IMC with both dual G5s and dual AV-30s. Hand flying, the G5 are better mainly because of the true HSI with glideslope, but the AV-30s are capable when they're working properly and its limitations understood. I have trust issues though.
Mine was way off until I set the calibration offset correctly. Now my altitude is within 20 feet of my original altimeter and airspeed is within about +/- 2 knots of over the entire range (I fly at 150 IAS so the range is wide). I calibrated my airspeed at 100 IAS. You also need to calibrate your OAT to the field elevation, not the analog gauge that came with your airplane. That made a big difference for me.After fixing the heading drift with our AV-30's, now we have an issue with the airspeed being off. I would be ok if it was within a few mph of the old analog airspeed indicator, but it's around 7-9 mph off on the high side. Moreover, at all altitudes the TAS on the display is slower that the indicated. That could be installation error or something is malfunctioning.
I've flown in IMC with both dual G5s and dual AV-30s. Hand flying, the G5 are better mainly because of the true HSI with glideslope, but the AV-30s are capable when they're working properly and its limitations understood. I have trust issues though.
I did self install. I wouldn't say "really easy". That would depend on skill level. The install involves wiring harnesses and pitot-static tubing. The OAT needs to be installed outside which usually requires drilling a hole in your airplane skin or an inspection panel.Find an A&P to check your work and do the AV-30 install yourself. Really easy.
I agree, UAvionix is an excellent VFR solution, but Garmin is superior for IFR.
Same here. My temperature sensor was off, which threw off the density altitude and true airspeed values. After I trimmed the temperature to read properly, the rest was also correct. That's something the installers should do, but at least it's user-configurable.Mine was way off until I set the calibration offset correctly. ...
Be sure to read the manual about calibrating the airspeed. I believe it should be done at a specific point in your green or white arc. (I don't remember exactly what it said). For my airplane that works out to 105 IAS. Yours will probably be different.I'm going to try trimming the OAT and IAS settings tomorrow. Have 4 legs planned. Hopefully I'll have it all set by the end of the day. I still having difficulty understanding why the TAS would consistently read slower than the IAS even if the OAT is off. Perhaps it's possible the TAS readout is in knots while the IAS is displaying in mph?
Did some testing today. AV-30 DG drifted 30 degrees in 10 minutes, 90 degrees in 20 minutes, and 180 degrees in 30 minutes. Straight and level flight.
Not yet, still gotta flash the unit to new firmwareDidn't you add the external magnetometer?
Not yet, still gotta flash the unit to new firmware
It's likely that a lot of labor charge is for removing the vacuum system. Often when you remove tubing all the zip ties will need to be redone for wiring.Hey, my vacuum system failed a few weeks ago so I’ve been doing all my hood training partial panel. I’m for sure going with dual AV-30s and an av-20 for the right seat and ripping out the vacuum system. Got quoted $3500 for install, is that reasonable?
It's likely that a lot of labor charge is for removing the vacuum system. Often when you remove tubing all the zip ties will need to be redone for wiring.
Actual AV-30 install is pretty easy. If installing three units most likely they will do a pitot-static hub quick connector. AV-20 requires only power and pitot-static.
Are you getting the magnetometer installed?
Be sure to read the manual about calibrating the airspeed. I believe it should be done at a specific point in your green or white arc. (I don't remember exactly what it said). For my airplane that works out to 105 IAS. Yours will probably be different.
TAS = IAS / (1 + (altitude x 0.00002))However, the TAS readout is still off. Sometimes it's ten mph less than the IAS others times it is just a few mph slower.
I think that / should be a *. Either that or TAS & IAS are swapped.TAS = IAS / (1 + (altitude x 0.00002))
The 4 Types Of Airspeed, And What Each One Means For You
Airspeed is more than simply reading off your airspeed indicator.www.boldmethod.com
Serves me right for copying from the interwebs.I think that / should be a *. Either that or TAS & IAS are swapped.