Air Vent Noise

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Steve
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Re: Air Vent Noise

Post by Steve »

So, today I taped the top half of the pilot side vent. I used 3 inch wide white vinyl tape. It looks reasonably good (see picture below). I don't yet know how durable it is. It was easy getting the duct tape off which had been on a couple of weeks.

Will try to fly tomorrow to see what the airflow is through the pilot's side with the top half taped off.

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Antoine
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Re: Air Vent Noise

Post by Antoine »

Just did same on my plane yesterday, only pilot side.
I was busy making another experiment so did not spend too much time on it.
Findings:
Noise is less aggressive
Airflow at least as strong as before.
I found out that I had a big air leak which made its way between the instrument panel and it's cover, near the air vent. It may be that this was always present and the additional pressure made it perceptible...

I will keep the tape for now and do a plug sometime. We need to be careful about the inner aerodynamics, I took a look and believe this could yield some further improvement.
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Kurt h
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Re: Air Vent Noise

Post by Kurt h »

I taped the top inlet on both sides and went for a flight. No instruments to measure results but the airflow was definitely higher. It may have been a bit quieter but still a significant increase in noise that requires higher radio volume to compensate. But I will take the higher airflow here in Houston!
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Re: Air Vent Noise

Post by smoss »

I got around to trying the tape trick today, taping off the top half of the pilot side inlet. The noise was only reduced a smidge for me, but as for the others, the airflow really went up! Like sticking my head out the window! Bizarre. Anyways, I will try taping off the bottom instead next time to see how the sound changes.
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Re: Air Vent Noise

Post by smoss »

Today I taped off the bottom half of the inlets on both sides and gave it a try. Airflow was perhaps reduced a little bit, but WOW, nearly silent for both vents! I used duct tape and took it off afterwads (my tape leaves a residue if I leave it on for a while), but I suppose I'll just put some clear packing tape over the bottom halves and leave it there. If you haven't tried it yet, well worth doing.
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Re: Air Vent Noise

Post by Steve »

Steve:

Try taping the top half next time. My measurements show that it is just as quiet, but airflow actually INCREASES.

Steve
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Re: Air Vent Noise

Post by smoss »

Steve, I already tried taping the top half. Indeed the airflow did increase (a lot), but it was only marginally quieter for me.
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Re: Air Vent Noise

Post by Antoine »

Today I almost made an emergency landing after hearing some rather scary noises coming from the front of the airplane. It happened after a steep descending right turn.
After landing, I found out that the vinyl tape I had used to close the upper half of the inlet on the passenger side was shattered. Probably the extra pressure from the steep turn was too much for it.
The rattling noise made me at first think of engine damage, it was a scary minute before I had finished the diagnostics.

So be warned...

(I also took some time to examine the inlets and ducting. Mamma mia...
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Re: Air Vent Noise

Post by smoss »

Antoine- I had a similar experience when I tried using a lighter clear plastic packing tape on the vent. After level off, and increase in airspeed, it sounded like an orchestra of bongos coming out of the vents. It was the first time I tried that tape, so I figured it was that, and then after a few minutes, the bongos stopped on one side (the tape came completely off in flight), but continued on the other until I slowed down for landing. Needless to say I stick with the duct tape now.
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Re: Air Vent Noise

Post by Steve »

Mine is still on after 4 months...
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