Bearhawk Aircraft Bearhawk Tailwheels LLC Eric Newton's Builder Manuals Bearhawk Plans Bearhawk Store

Announcement

Collapse
No announcement yet.

Cabin noise level

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Cabin noise level

    Just returned from a 2 hour trip to dinner today. On the trip I took a sound level reading on the plane in cruise flight: 180 hp lyc with mt prop 2500 rpm 24.5 manifold pressure about 76 percent power and 10.5 gph about 115 knots true at 3000. I show 111 db at windshield level. If I position the meter at my firewall I exceed 120 db. Wonder if anyone else has sound readings.

  • #2
    I usually get around 90db in cruise in the cabin. In Mark's airplane I saw 108. This is on the ipad in my lap in both cases.

    Comment


    • Flygirl1
      Flygirl1 commented
      Editing a comment
      Must be an app for that? I'd love to know the difference between 240BP and 241BP. I have lots of insulation all around and above me, whereas 240BP does not and he has a skylite.
      Last edited by Flygirl1; 10-08-2017, 08:33 PM.

  • #3
    Yes, there are several apps. Not sure how accurate they are, but it's better than nothing I suppose.

    Comment


    • #4
      I have taken reading around the 110 mark, or a little less. Of course it depends on the measuring device a lot. The average mobile device seems pretty inaccurate / susceptible to user error.

      Comment


      • #5
        From reading in "another forum", the microphones built into the smart phones and tablets are accurate only to about 94-95 decibels. Anything above that is wildly inaccurate. But that is 3rd-hand information from someone who claimed to be an expert. In any case, use hearing protection for all occupants. ANR headsets, passive headsets, earplugs, or whatever -- just use SOME form of hearing protection.
        Jim Parker
        Farmersville, TX (NE of Dallas)
        Patrol Quick-Build Serial # P312

        Comment


        • #6
          We wear active headsets. The reading were taken with a sound meter. Loud sound is tiring and I did insulate to reduce the level. Wish while I had the meter that I had take readings at other power settings. Glad to hear that it seems that I improved it some.

          Comment


          • #7
            What did you insulate, what products did you use, and did you quantify the results afterwards with the sound meter?
            Brooks Cone
            Southeast Michigan
            Patrol #303, Kit build

            Comment


            • #8
              I insulated with 1/4 inch low density foam during the build. I think the foam was 12 lbs / cu ft if memory is accurate. I fabric covered the interior then glued the foam to the outside surface then covered the exterior. I do need to find some material to cover the back side of the floor though I have carpet on this surface. My biggest motivation for insulating was to try to reduce cold transmission during winter flying, sound was a secondary concern.

              Comment


              • Flygirl1
                Flygirl1 commented
                Editing a comment
                I used foil backed bubble wrap stuff and a foil backed cotton cut up blue jean material from Home Depot. Also have carpet. These together really stop any "oil canning on the floor. I put the bubble wrap stuff between the aluminum floor and the frame. I also put a foil backed light weight cut up cotton blue jean type material under the carpet on top of the aluminum. This particular stuff is also on the side walls front to back and I have pink insulation on the entire top above the cabin behind and on top of the headliner. Now ya all can see why my plane is a bit heavier than some, most. ;-) (1247lbs) On a side note, whatever your using think about doing a burn test. I can't remember exactly what the criteria was, but all my materials passed. I think the fire had to go out in a rather quick time frame. I used this same blue jean material on the fire wall and sprayed it with Flex Seal to make it look better. After i had it installed I had an after thought about the burn test--it failed, miserably!! Switched to a high heat black spray paint.

            • #9
              Just be aware, a cheap sound meter that feeds you one number (all the frequencies summed together) is really only good for relative comparisons. So if you're measuring with the same microphones, same pre-amps, same mic location, etc etc etc it can be useful. But that's about it!
              Mark
              Scratch building Patrol #275
              Hood River, OR

              Comment


              • #10
                My plan for the Patrol is to make it as light as I can make it (though I'm certain it won't be as light as Bob's!), so I don't plan to "line" the interior anywhere except the baggage compartment. I expect I'll use insulation only on the firewall - mostly to avoid heat transfer in our gloriously "warm" summer months (avg highs > 95F).

                I already own two ANR headsets that are quite nice in the winter, but just too hot to be comfortable in the summer. I also own two sets of Halo in-ear passive noise reduction headsets that are amazingly light and comfortable, and provide very close to the same noise reduction as the ANR headsets. Hopefully, that will be enough to keep things comfortable, acoustically.
                Jim Parker
                Farmersville, TX (NE of Dallas)
                Patrol Quick-Build Serial # P312

                Comment

                Working...
                X