What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Whistling sound in my RV-9A

T

TBoyner

I'm New Here
I have been flying my -9A for 6 years now, and I have enjoyed it for 300 flight hours.
Since the first flight, people on the ground have remarked about a whistling sound from the aircraft when I fly by. I have wondered about he origin of this aerodynamic sound but not really digged too much into it, since you could'nt here it in the plane.
But lately this sound can be heard inside the aircraft, even with my Lightspeed ANR headset on.
A hight pitched tone, which gets higher with more speed, not related to engine RPM or alternator speed. From what I understand it is aerodynamic, possibly coming from an air leak in the tip-up canopy or somewhere else.
I have a thin foam list sealing the canopy to the airframe, which has been a little worn over the years, could a small air leak here produce such an annoying sound?
Or should I start looking somewhere else?
Anybody else out there with similar problems and a solution?

Best regards
Thomas Boyner
 
Most believe it's from the joint or opening between the horizon tail.surface and elevator. Maybe the hinge opening. Mine whistles as do most 9s . You can place some tape carefully around the openings and minimize it for a test but not recommended for permanent. Gives it character!!
 
that whistle on the -9

...has been with me since first flight, and i love it. at reduced throttle settings and slight descents at relatively high speeds it sounds great. folks on the ground usually love it too.
 
I too am the proud driver of a whistling 9A. Just part of the personality of this fine aircraft!
 
I fly several models of the 737, the older being loud because of poor turbulent airflow over nose and windshield, later models have vortex generators in FRONT of the windshield to energize and change flow possibly streamlining and smoothing airflow over cockpit and windshield, it makes for quieter cockpit....might be a thought for your application.
Tom
 
barely there

I can hear the whistle.... just barely, with Lightspeed headsets. Don't mind it and it rarely gets mentioned by groundpounders...
 
I played around with silencing the whistle.

If you tape some business cards over the slots on the rudder and elevators, you'll make it less pronounced, but it would still whistle at certain speeds.

IMG_7329-M.jpg


IMG_7330-M.jpg


I ended up flying with these on for a few months, and ended up taking them off. I really only notice the whistle when I throttle back for descent and the engine noise is less.
 
Bruce, that is one of the funniest things I have seen on VAF! What a crack up. I can't believe you flew around with the cards taped on. I can imagine the comments you got!!
 
Bruce: Boss I need another box of business cards…….

Boss: I just got you a box last month

Bruce: I’ve been doing a lot of networking, doing my best to get the company noticed up and down the West coast.

Boss: Great job Bruce, our dept could use more like you...........
 
Last edited:
We love our whistling -9. It does so because it is so darn happy to be in the air.
 
Whistling 9A

A friend of my brother noticed my 9a's whistle while I was in the pattern for landing. Since the whistle indicates aerodynamic "obstruction" I figured that if I could find it and correct it, it had to be good for 10-20 extra kts at cruise (actually I was hoping for a measurable change)! I tracked it down to the hinge openings on the big 9 elevator. While in slow flight with the nose trimmed up more of the lower hinge openings are exposed to airflow and create the whistle. I did not want to block the openings with metal (can't see the hinges/bolts for preflight) so I used lexan, heated and curved to the same radius as the leading edge of the elevator. Installed some plate nuts, shaped the lexan to clear the hinges and installed the inserts with flush #4 SS screws----whistle gone! While I was at it I also made inserts for the rudder hinge openings.


Oh, btw, the speed difference at cruise was ------ zero!! However, I did notice slightly more elevator authority on landing.

Cheers,

db
 
Last edited:
You must log in or register to reply here.
Back
Top