Kitfox Aircraft Stick and Rudder Stein Air Grove Aircraft TCW Technologies Dynon Avionics AeroLED MGL Avionics Leading Edge Airfoils Desser CPS Parts EarthX Batteries Kitplane Parts
Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 24

Thread: Balance Master

  1. #11
    Senior Member PapuaPilot's Avatar
    Join Date
    Nov 2013
    Location
    Nampa, Idaho
    Posts
    793

    Default Re: Balance Master

    Does anybody know if they make one that fits on the Continental IO-240? I like the idea of having your prop & engine in balance at all RPMs.
    Phil Nelson
    A&P-IA, Maintenance Instructor
    KF 5, Continental IO-240
    Flying

  2. #12
    Super Moderator Av8r3400's Avatar
    Join Date
    Jan 2009
    Location
    Merrill, WI
    Posts
    2,795

    Default Re: Balance Master

    If you follow the link to ACS, youíll see they do. John and others have stated they werenít happy with the results on a direct drive engine. I would hypothesize that the harmonic pulses in a direct drive situation may negate some of the balancing properties.
    Av8r3400
    Kitfox Model IV
    The Mangy Fox
    912UL 105hp Zipper
    YouTube Videos

  3. #13
    rdooley79's Avatar
    Join Date
    Jan 2013
    Location
    lafayette, CO
    Posts
    92

    Default Re: Balance Master

    Iím finishing a 912 install on my 4. Hal did the build of the engine for me and he recommended using two balance masters. One on the mag end and on the prop as well so I put them on my 912. Probably a couple weeks from first run up and no pirep yet. Hal recommended it highly so thereís that...
    Kitfox IV - 1200 (1994) #1830
    Rotax 670 (90+hp)
    C-Box 3:1
    Warp Drive 3 Blade 72"
    Grove Gear, Wheels, Brakes
    22" Desser Tundra Tires

  4. #14

    Join Date
    Oct 2017
    Location
    St. George, UT
    Posts
    72

    Default Re: Balance Master

    Quote Originally Posted by rdooley79 View Post
    Iím finishing a 912 install on my 4. Hal did the build of the engine for me and he recommended using two balance masters. One on the mag end and on the prop as well so I put them on my 912. Probably a couple weeks from first run up and no pirep yet. Hal recommended it highly so thereís that...
    Two??? I was looking at getting one... now, I have to look at getting two... 😜

  5. #15
    Senior Member rv9ralph's Avatar
    Join Date
    Aug 2014
    Location
    Greenleaf, ID
    Posts
    390

    Default Re: Balance Master

    Two??? I was looking at getting one... now, I have to look at getting two... 😜
    So here is something to think about. In the Rotax 912/14/15 series there are two centers of rotation. The prop hub at the top of the gearbox, and the Crankshaft (I know the camshaft is also a different center of rotation but we will leave that one for now). These are separated by 4-6 incise. The prop and it's rotational forces are turning at 2.27 or 2.43 times slower than the crank's rotational forces. When trying to balance this, you have to consider both of these sources of acceleration.

    To this, the suggestion of two balance masters does make sense.

    Ralph

    ps - I am not an engineer nor do I claim to be.

  6. #16
    Senior Member efwd's Avatar
    Join Date
    Jun 2015
    Location
    Yorba Linda, CA
    Posts
    2,115

    Default Re: Balance Master

    Hmmm. I used a Dynavibe to balance my prop. It worked and I may even swap to the balance master regardless. I seriously hope my $22k Rotax was balanced at the factory.
    Eddie Forward
    Building
    SS7, 912iS, Garmin G3X

  7. #17
    Senior Member rv9ralph's Avatar
    Join Date
    Aug 2014
    Location
    Greenleaf, ID
    Posts
    390

    Default Re: Balance Master

    I used a Dynavibe to balance my prop. It worked and I may even swap to the balance master regardless.
    Eddie, didnít you report you only had a small vibration that popped up at certain times... could it be a multiple of the reduction ratio? Just a thought.

    Ralph

  8. #18
    Senior Member jrevens's Avatar
    Join Date
    Aug 2009
    Location
    Arvada, CO
    Posts
    1,523

    Default Re: Balance Master

    IMG_1368.jpgIMG_1386.jpgIMG_1370.jpgIMG_1385.jpg
    I flew for 1.5 hours on 1/16/20 with the Balance Master installed. The airplane didn't feel as smooth as before, but definitely smoothed out more after full throttle run-up. Today I installed my balancing equipment to get some real numbers. After warm-up, I advanced to 5000 rpm, took a vibration reading, then did the same thing at 4000, 3000 & 2000 rpm. I then went back up in 1000 rpm steps to 5000. I then removed the Balance Master and performed the same exercise again. I had previously dynamically balanced the assembly to 0.02 to 0.03 ips at full-throttle static of approximately 5100 rpm. Here are my results and observations -

    With Balance Master - Starting at 5000 rpm - 0.04, 4000 - 0.04, 3000 - 0.12, 2000 - 0.02 Starting at 2000 - 0.03, 3000 - 0.07, 4000 - 0.03, 5000 - 0.10

    Without BM - Starting at 5000 rpm - 0.02, 4000 - 0.02, 3000 - 0.01, 2000 - 0.02 Starting at 2000 - 0.02, 3000 - 0.02, 4000 - 0.03, 5000 - 0.03

    I allowed time for things to "settle down" before each reading, and observed that with the BM it took a minimum of 30 sec. to 1 min. (sometimes considerably longer) to reach the best balance condition. There was no delay without the BM. I'm not certain why the spike at 5000 rpm when going from 4000 to 5000 with the BM as compared with starting at 5000. Hysteresis in the throttle cable when pushing as opposed to pulling on the throttle arm (I don't have the throttle springs) creating a little carb imbalance may be a factor, but I don't see the same thing without the BM.

    So, my experience is smoother operation without the Balance Master, and much smoother during the transition "settling down" periods. I think that the Balance Master would potentially offer a good improvement/option for an out-of-balance condition if dynamic balancing was not easily accomplished, such as when a small "skull-cap" spinner is used on a Rotax. For me, there is no doubt that my situation is better with a good dynamic balance job alone. Your mileage may vary.
    Last edited by jrevens; 01-18-2020 at 10:32 PM.
    John Evens
    Arvada, CO
    Kitfox SS7 N27JE

  9. #19

    Join Date
    Sep 2015
    Location
    Cave Creek, AZ
    Posts
    134

    Default Re: Balance Master

    Very interesting. Thanks much for taking the time to do this and report the findings. Maybe some others will chime in with their findings.

    Clark

  10. #20
    Senior Member JoeRuscito's Avatar
    Join Date
    Jun 2018
    Location
    Charleston, SC
    Posts
    287

    Default Re: Balance Master

    Great report. Thanks John.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •