Engine mount bushings

Discussion in 'Workshop Tips and Secrets / Tools' started by Charles_says, Sep 5, 2019.

Help Support HomeBuiltAirplanes Forum by donating:

  1. Sep 5, 2019 #1

    Charles_says

    Charles_says

    Charles_says

    Well-Known Member HBA Supporter

    Joined:
    May 27, 2019
    Messages:
    137
    Likes Received:
    48
    I don't seem to have privileges to post on the RW19 site but I am able to view it.
    Don't know why....if some one can explain this... Thanks.

    In the meantime I'd like to say that I used these same bushings to double my
    vibration proofing, by placing a set between the engine and the mount, and
    again between the mount and the airframe.
    silicon bushings.png
    My engine is the Kawasaki 440A 2 stroke, mounted inverted,
    with PSRU above.
    will let you all know how this works when I start my taxi testing, sometime in the near future.
     
  2. Sep 5, 2019 #2

    Charles_says

    Charles_says

    Charles_says

    Well-Known Member HBA Supporter

    Joined:
    May 27, 2019
    Messages:
    137
    Likes Received:
    48
    Bushings installed between engine and mount installed last year, during fitting. I sliced them in half
    before installing. will install proper bolts before completion engine mount to airframe not shown.


    Engine on its motor mounts.jpg
     
    John wadman likes this.
  3. Sep 6, 2019 #3

    MadProfessor8138

    MadProfessor8138

    MadProfessor8138

    Well-Known Member

    Joined:
    Nov 4, 2015
    Messages:
    608
    Likes Received:
    248
    Location:
    Ekron,Kentucky
    I dont know if that is my fault but I asked the Admin to set the build logs so that only the creator of the log can post to it.
    In my opinion,the Build Logs are for individuals wanting to show their project progress without dealing with posts that could possibly derail the thread.
    This will keep the thread clean,civil and easier to navigate for people following the build.
    If you have information,constructive criticism or just want to say hi to the log creator then shoot them a private message...I'm sure they will glad to hear from everyone.

    Kevin
     
  4. Sep 6, 2019 #4

    John wadman

    John wadman

    John wadman

    Well-Known Member

    Joined:
    May 27, 2019
    Messages:
    192
    Likes Received:
    217
    Yep, these are harder than rubber but they do compress. I’m hoping they do the job and last longer than rubber bushings. Price was right and I get two sets.
     
  5. Sep 6, 2019 #5

    Dan Thomas

    Dan Thomas

    Dan Thomas

    Well-Known Member

    Joined:
    Sep 18, 2008
    Messages:
    4,860
    Likes Received:
    2,071
    Is there any shock-absorbing material between the bolt shanks and the aluminum mount? If not, the bolts will wear the mount holes and transmit vibration. It can get noisy.
     
    Charles_says and Pops like this.
  6. Sep 6, 2019 #6

    Pops

    Pops

    Pops

    Well-Known Member

    Joined:
    Jan 1, 2013
    Messages:
    7,140
    Likes Received:
    6,027
    Location:
    USA.
    The shock mounts I bought from NAPA had a shoulder on one end . Make a 4130 steel washer to go over the shoulder. The washer is welded between two short lengths of 4130 tube the ID the same as the OD of the rubber mount and about 1/8" shorter. Mounting bolt can not contact the washer.
    Wish I could do a drawing, scanner is broken.
     
    BoKu likes this.
  7. Sep 6, 2019 #7

    BoKu

    BoKu

    BoKu

    Well-Known Member HBA Supporter

    Joined:
    Aug 16, 2013
    Messages:
    2,323
    Likes Received:
    2,913
    Location:
    Western US
    I used to do that a lot; make a sketch by hand, scan it, and then email it or whatever. These days what I usually do is take a photo of the sketch with the camera in my phone, and post that.
     
  8. Sep 6, 2019 #8

    Charles_says

    Charles_says

    Charles_says

    Well-Known Member HBA Supporter

    Joined:
    May 27, 2019
    Messages:
    137
    Likes Received:
    48
    That's a great idea!
     
  9. Sep 6, 2019 #9

    12notes

    12notes

    12notes

    Well-Known Member Lifetime Supporter

    Joined:
    Aug 27, 2014
    Messages:
    838
    Likes Received:
    512
    Location:
    Louisville, KY
    I'm pretty sure you're talking about the same method used on the Hummelbird, which looks like this.
     

    Attached Files:

    Pops likes this.
  10. Sep 6, 2019 #10

    Pops

    Pops

    Pops

    Well-Known Member

    Joined:
    Jan 1, 2013
    Messages:
    7,140
    Likes Received:
    6,027
    Location:
    USA.

    Yes, the same. Weld the outside of the washer to the two tubes. Then the engine mount tubing is welded to the outside of the larger tubes. Picture sure helps. Thanks.
     
  11. Sep 6, 2019 #11

    Charles_says

    Charles_says

    Charles_says

    Well-Known Member HBA Supporter

    Joined:
    May 27, 2019
    Messages:
    137
    Likes Received:
    48


    Yep! Same here. My engine rated 38 HP, weighs but 58 lbs, So I cut them in half and used one complete bushing for each AN4- bolt Big washer on top, and on bottom. No sleeve though, but that idea, is up-gradeable for me if needed. I do have some .375 OD 4130.
    Time will tell.

    So my engine will sort of "float" in a sea of Polyurethane.The idea is : engine, bushing, engine mount, bushing, airframe. What my photo doesn't show is the perpendicular rear angle, which is isolated from the airframe with same bushings.
     
  12. Sep 7, 2019 #12

    Daleandee

    Daleandee

    Daleandee

    Well-Known Member

    Joined:
    Sep 11, 2015
    Messages:
    896
    Likes Received:
    561
    Location:
    SC
    These appear to be the same ones I used on the bed mount for the Corvair engine on my plane. Work great so far ...

    Dale
    N319WF
     
  13. Sep 7, 2019 #13

    Pops

    Pops

    Pops

    Well-Known Member

    Joined:
    Jan 1, 2013
    Messages:
    7,140
    Likes Received:
    6,027
    Location:
    USA.
    Straight tail C-172's with the Cont -0-300 engine also has rubber bushings between the engine mount and fuselage. Same in the early C-182 if I remember correctly.
    The old 6 cylinder 0-300's are smooth and with the engine to engine mount bushing and then the engine mount to the fuselage bushings its super smooth. That is what you want for a camera platform .
    My old 1959 C-172 was highly modified and lighten in weight and flown in the "restricted Category".
    No paint, no doors if wanted, no interior except for the pilots seat. Camera ports in the floor and both rear window area. King IFR with Autopilot.
     
    Last edited: Sep 7, 2019

Share This Page



arrow_white