Sqeal in headset

[246rk]

Just installed Skyview 10 in. When I apply full power for take off I get a high pitched steal in my head set for 2 to 3 seconds on the take off roll and then it goes away. Only on the ground during take off. Don't think it's inter come but not sure where it's coming from. Any suggestions??

[Sam Buchanan]

Angle of attack warning tone? You didn't state which RV you are flying or if AOA is installed, but the AOA can alarm briefly in a taildragger on takeoff.

Oh...welcome to VAF!

[Trapper]

Sounds for sure like your AOA aural warning if you have one in your left wing. Simply open the access panel and loosen the attach bolts to reduce the AOA. I had the same problem.

[RV7A Flyer]

Or...

Calibrate it using Dynon's procedure (mine goes off during take-off, as expected, starting with a steady tone, then fast beeps, then slow, then none, rather quickly),

or

Turn off the aural warning in the setup menus.

[246rk]

THANKS GUYS> it is an RV6A with the AOA in the left wing. So by removing inspection plate I lower or raise the opening (front) end of the pitot tube relative to the cord? How much?

[rvbuilder2002]

Originally Posted by 246rk

THANKS GUYS> it is an RV6A with the AOA in the left wing. So by removing inspection plate I lower or raise the opening (front) end of the pitot tube relative to the cord? How much?

Sorry to be so blunt, but questions like this in the forums make the hair stand up on the back of my neck.....

You now have equipment installed in your airplane that could make it safer if it was properly installed and calibrated, but you are willing to make adjustments based on a consensus in an online forum?
Relying on an improper calibrated AOA is likely more dangerous than not having one at all.....

My recommendation is that you spend some time with the documentation and then calibrate it following Dynons documented procedures (or you get direct/personal help from someone that can do it for you).

[RV7A Flyer]

Originally Posted by rvbuilder2002

Sorry to be so blunt, but questions like this in the forums make the hair stand up on the back of my neck.....

You now have equipment installed in your airplane that could make it safer if it was properly installed and calibrated, but you are willing to make adjustments based on a consensus in an online forum?
Relying on an improper calibrated AOA is likely more dangerous than not having one at all.....

My recommendation is that you spend some time with the documentation and then calibrate it following Dynons documented procedures (or you get direct/personal help from someone that can do it for you).

Agreed. And that's assuming the sound was from the AOA, which is not certain (yet).

[Trapper]

I think that RV7A Flyer is thinking of the AOA calibration associated with the Dynon Deluxe Pitot Probe, which displays various levels of AOA on the PFD in multiple colors. As he so eloquently stated, there's a Dynon procedure for calibrating this and I'd recommend that you follow it. However, I'm thinking that you have the same issue I had back when I first powered up my airplane: a loud squeal tied to the Van's AOA mechanical probe with a tab sensor in the left wing leading edge. No need to comb your neck: this was an option that you and I got with the Van's kit and it merely warns of an impending stall. You can set it to go off with whatever margin above the stall you want and most RV's don't even have one. It's wired from the wing to a small, independent circuit board (mine's on the firewall) then directly to your audio panel so any Dynon calibrations will have NO effect on the warning, i.e., it's a completely independent system. Without hiking out to my hangar to verify (i.e., check your installation guide), I recall the installation as very general and uncalibrated because there are no marks to reference inside of the wing where the unit is mounted. I merely opened the access panel and reduced the AOA of the unit incrementally, comparing when the squeal occurred as part of my fly-off. Once I had it set where I wanted it, I left it alone. Also: there's no volume control for the squeal and mine was pretty loud so I installed an inline resistor to lower the intensity. I had this all checked out by our local avionics shop and they verified that it was done properly.

Hope this helps!

RV-8 N798RT
IO-375
Dual 10" Skyviews

[RV7A Flyer]

Originally Posted by Trapper

I think that RV7A Flyer is thinking of the AOA calibration associated with the Dynon Deluxe Pitot Probe, which displays various levels of AOA on the PFD in multiple colors. As he so eloquently stated, there's a Dynon procedure for calibrating this and I'd recommend that you follow it. However, I'm thinking that you have the same issue I had back when I first powered up my airplane: a loud squeal tied to the Van's AOA mechanical probe with a tab sensor in the left wing leading edge. No need to comb your neck: this was an option that you and I got with the Van's kit and it merely warns of an impending stall. You can set it to go off with whatever margin above the stall you want and most RV's don't even have one. It's wired from the wing to a small, independent circuit board (mine's on the firewall) then directly to your audio panel so any Dynon calibrations will have NO effect on the warning, i.e., it's a completely independent system. Without hiking out to my hangar to verify (i.e., check your installation guide), I recall the installation as very general and uncalibrated because there are no marks to reference inside of the wing where the unit is mounted. I merely opened the access panel and reduced the AOA of the unit incrementally, comparing when the squeal occurred as part of my fly-off. Once I had it set where I wanted it, I left it alone. Also: there's no volume control for the squeal and mine was pretty loud so I installed an inline resistor to lower the intensity. I had this all checked out by our local avionics shop and they verified that it was done properly.

Hope this helps!

RV-8 N798RT
IO-375
Dual 10" Skyviews

Perhaps...but the OP said that he "just installed" a SV (implying that the noise wasn't there before, so likely coming from the SV *assuming* he wired the SV audio out to his audio panel), and

"it is an RV6A with the AOA in the left wing. So by removing inspection plate I lower or raise the opening (front) end of the pitot tube relative to the cord? How much?"

Bottom line: it's unclear what is causing the noise in the first place, which would be the first thing to determine. Then, and only then, start diagnosing the problem (if there is one) and fix it.

[Trapper]

Excellent point, but since 246rk is getting a single-toned loud squeal vs. all the different tones the SV AOA provides, suspicion points to the mechanical AOA probe. Smart suggestion to determine the source so I'd suggest capping off the mechanical probe to determine if that's where the squeal is coming from. My money says that it is. ;-))