Couple of videos from INSIDE a Subie RV-7

cjensen · #1 06-21-2007, 10:42 AM

I shot some video during my flight with Benny Butler in his Egg H6 powered RV-7. The first video is a takeoff from my home airport in Bloomington, IL. Climbout was 1800fpm with all temps normal. He has the Gen2 redrive and an IVO Magnum prop.

Egg Subie takeoff video from the inside

The second video is of us landing at Jack Holland's strip (JACKR on VAF)...

Landing

Enjoy!

RV7Guy · #2 06-21-2007, 10:25 PM

I have a vacuum cleaner that sounds like that.

gmcjetpilot · #3 06-22-2007, 04:28 PM

Hard to tell how LOUD it is, but you can hear the wind noise which may mean something, like the engine noise is not overpowering the wind noise? (may be) However don't know where the audio pickup is.

Scott over at Van's test flew a customer built RV-9A (Subie) against a Lyc powered RV-9A (Van factory demo plane). His subjective comment was, its not as much quieter but different. I assume he means frequency. The Lyc is definitely deeper or throatier and I assume louder. The ANC headsets is the solution, but as I understand it they are tuned to take out lower freqs. I wounder if they work as well with the Subie or Mazda? Probably does not make any difference to the headset since the passive reduction is always still there.

Would be nice to go up with audio equip (ground and air) and measure the dB's and frequency.

On paper the Subie should be lower noise for two reasons: Water cooled jacket and I think they use a muffler don't they? Not sure. I heard a water cooled Lyc with experimental liquid-jugs on a test stand, it sounded just like a car engine. With air-cooled all the mechanical clang and bang is right there. However Mazda's are water cooled, but I've heard Rotary fly-by and find them to be the most offensive or not pleasing to me personally.

A P-51 or a large radial engined fighter does a fly-by, its loud but no one complains (or should).

mburch · #4 06-22-2007, 04:48 PM

Quote:

Originally Posted by gmcjetpilot

The Lyc is definitely deeper or throatier and I assume louder. The ANC headsets is the solution, but as I understand it they are tuned to take out lower freqs. I wounder if they work as well with the Subie or Mazda? Probably does not make any difference to the headset since the passive reduction is always still there.

I used to own a Subaru-powered RV-9A, and my impression was that my Lightspeed ANR headset did not do a good job of getting rid of the high-frequency sounds from the engine. With the muffler installed it was loud by tolerable; without it was painful at the high power settings required to get anywhere. I think you're right that the ANR headset is optimized to cancel Lycoming-style frequencies (makes sense to me).

This was a couple years ago - the current crop of Subaru engines may or may not be the same way.

mcb

cjensen · #5 06-22-2007, 04:52 PM

He has a pretty good air leak thru his canopy somewhere. The mic pickup is on the back side of my little camera, but I couldn't tell where the air was coming from.

That airplane does not have an exhaust on it, however most of them do. In that airplane, I'd say the noise level is *slightly* lower, but still noisy. The 9A H6 that I flew in was REALLY quiet, but it had a FULL interior and dual exhausts.

I used my Halo's in the airplane in the video above, and they were plenty suffiecient for the higher pitched Subie.

A Mazda's noise comes from the exhaust alone. They are really quiet mechanically.

rv8ch · #6 06-23-2007, 12:38 AM

Quote:

Originally Posted by cjensen

...That airplane does not have an exhaust on it, however most of them do. In that airplane, I'd say the noise level is *slightly* lower, but still noisy. The 9A H6 that I flew in was REALLY quiet, but it had a FULL interior and dual exhausts...

This aircraft is flying with no muffler at all? Wow, that will help us keep airports open. Subaru engine noise as heard from the ground is rather annoying. Even Eggenfellner will tell you this. I hope it's just a temporary situation.