Van's Air Force
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Dynamic balance results?
- Thread starter Jesse
- Start date
CharlieWaffles
Well Known Member
YIO-540-D4A5 from Vans and the Hartzell 3-blade composite Semitar prop:
Out of the box, it was .092 In/S using a MicroVibII.
Was so small that we didn't try to improve it as the stock flywheels from Vans no longer have holes to be able to use to add weight. So would require removing flywheel and having it machined.
http://myrv10factory.wordpress.com/2013/09/09/flight-testing-continues/
Out of the box, it was .092 In/S using a MicroVibII.
Was so small that we didn't try to improve it as the stock flywheels from Vans no longer have holes to be able to use to add weight. So would require removing flywheel and having it machined.
http://myrv10factory.wordpress.com/2013/09/09/flight-testing-continues/
Walt
Well Known Member
No need to machine the flywheel (it would be impossible to calculate how much and where to remvoe material from anyway), in this case you just add weight to the spinner bulkhead by drilling one or two holes for the balance weights (bolts/washer) this is an approved procedure.
Continental's don't have a flywheel.
0.100 IPS is considered the after balance upper limit which you were close to, my goal is anything below .040 IPS but can usually do better.
.01
Just did a balance on my Super Decathlon after a prop rebuild. Balanced it at 2500 as that is where I usually run when flopping around the sky.
Got it to .01.
First run said add 24 grams - drilled the back-plate and added washers and a nut and bolt. Second run said add 5 grams- large washer under a spinner screw. Third run we were down to .04, needed a wee bit at 9:00 - added a small washer under another of the spinner bolts. Fourth run said we were .01 - leave it alone!
Runs smooooth.
Just did a balance on my Super Decathlon after a prop rebuild. Balanced it at 2500 as that is where I usually run when flopping around the sky.
Got it to .01.
First run said add 24 grams - drilled the back-plate and added washers and a nut and bolt. Second run said add 5 grams- large washer under a spinner screw. Third run we were down to .04, needed a wee bit at 9:00 - added a small washer under another of the spinner bolts. Fourth run said we were .01 - leave it alone!
Runs smooooth.
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Walt
Well Known Member
That's why in 99% of the cases I install weights at 2 seperate locations on the back plate or flywheel, that gives you the ability to tweak the polar location and weight. Leaving various washers under spinner bolts works but it is not a good practice or an "approved" procedure (the next time you or your A&P take the spinner off it may not go back on the the same way).
douglassmt
Well Known Member
N242BD
Initial number was 0.099 ips
He decided to make one try at getting it a little better, added the recommended weight (one bolt, 7 grams as I recall).
Final number was 0.028 ips. Said that was the lowest he had ever achieved.
Initial number was 0.099 ips
He decided to make one try at getting it a little better, added the recommended weight (one bolt, 7 grams as I recall).
Final number was 0.028 ips. Said that was the lowest he had ever achieved.
brianwallis
VAF moderator
Walt Knows
Walt knows what he 's talking about. I see anywhere from .2 to .5 on a regular basis prior to adding weights. Sometimes you get lucky and only need weight in one location. After years of balancing props, I've only managed to get 0.00 about 3 times. In theory you should not be able to feel 0.07. Feel free to call or PM if you have any questions.
Walt knows what he 's talking about. I see anywhere from .2 to .5 on a regular basis prior to adding weights. Sometimes you get lucky and only need weight in one location. After years of balancing props, I've only managed to get 0.00 about 3 times. In theory you should not be able to feel 0.07. Feel free to call or PM if you have any questions.
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Geico266
Well Known Member
I don't remember the numbers, but it was a dramatic difference in my -10. I have the Dynavibe also. Works great, now very smooth.
I defer to Walt & Bryan for tech advice. I only do 2-3 birds a year now. Balancing is an art, best done by experienced and recently proficient mechanics.
I defer to Walt & Bryan for tech advice. I only do 2-3 birds a year now. Balancing is an art, best done by experienced and recently proficient mechanics.
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