Dynavibe today

[Dorsal]

Finally got around to using the Dynavibe today, I found the results very impressive. Started with a vibration factor of .78 IPS (inches per second) and managed to reduce it to .07 with the weights in the picture. The effect was readily apparent throughout the RPM range definitely worth the effort. The initial bracket was set up for both the accelerometer and the optical pick up however the OP needs to be 6 inches back and not pointed at a shiny surface. The process was fairly straight forward and took less than an hour once set up. As others have mentioned balancing your prop really does take the engine to a new level of smoothness.
At some point I will paint the back of the spinner plate black so as to leave the reflective tape in a place where I won't normally see it, will also probably move the weights inboard bolted to the plate.

[SkyPirate]

Awesome Finn.,, I just replaced the prop on my hurricane because it was so out of balance I thought I'd have to remove an inch off one tip to balance it( the prop that was on it had no markings so I don't know the manufacturer but it was a 68/28 ) ,..I put a 2 blade GSC ground adjustable prop on it,..smooth as ice now 62/28,..set at 15 degrees

[Av8r3400]

Fin - On that technique of balancing, is there a method to balance if you don't have a large spinner with a backing plate to attach washers? I just have the little bullet nose over the center of the prop hub.

I know that my uber-heavy weight Warp prop has to be out of balance...

[Dorsal]

Not sure, the Dynavibe simply tells you where to remove weight (or add weight @180 degrees). It does not tell you how much so it is a trial and error process. You could put washers under the nut of the outer blade grip bolts (possibly getting a set of longer bolts). I suppose you could also trim the blade but that is not something I would be willing to mess with.

[SkyPirate]

I've seen where like Fin said ..people have added washers to the light side,..also seen where some have drilled holes on the heavy side,..or drilled on the light side and put a weight in the hole and epoxied it in place.

I think Steve aka slyfox and Andy aka Akarmy have the dynavibe system too,.. both very pleased with it

[War Eagle]

Would love to have one but I can't handle the $1500 or so it costs. Would be cool if there was a group or agency that would rent them out for doing this kind of work.

My CS prop assembly was balanced at the mfg factory but I am sure I could benfit from an on the plane assembly.

Our local EAA has some tools that can be borrowed but the cost of this tool would be harder to generate the funds for.

[SkyPirate]

Yes they are a bit pricey, but knowing what vibration can do to a $20,000.00 or more engine, would it justify the cost if it prolonged the life of everything on an aircraft including the engine?
Vibration is definately an enemy to the aviation world

[Slyfox]

I keep the degrees on the hub, and the tape on the prop. Than all that is needed is to run it and if I need weight, I use stick on tire weights. When I have it balanced I take the weight back off and drill an 1/8 inch hole and pop rivet it in place. I do my lycoming that way as well.

[Zorro]

I got my prop balanced 2 days ago on the 9/12/11 at Dash Air in Trout dale OR. KTTD. It was out .95 and Darrel got to .34 darn near perfect. I had been trying to work those vibrations for the last 75 hours.
I wished I done it sooner, no more gritting my teeth at certain RPM setting.

[Slyfox]

you can do better. I got mine down from 1.20 to .03. Like I stated, I use those stick on wheel weights. Afterwards I pop rivet them into place. Of course you will need a spinner. I have a fiberglass spinner.

[Zorro]

I have fiberglass too. I just flew 3.3 hours, and checking my numbers I'm only getting 4800 rpm on take off so I think I need to flatten my prop before I do any more balance work.

[Slyfox]

if I remember my numbers from way back when I had a fixed it was around 5100.

[wadeg]

Zorro,
How much does Dash Air at KTTD charge for a balance?
Wade (7S9)

[Zorro]

It was 260.00 I figure I saved many hours on my engine, and some grey hairs. Also it was same day day service I called they said come on down, I noticed right away on taxi, and my climbe out was so smooth. I went 3.3 hours today and the whole way I was aware how smooth it ran.

[GDN]

Just bought the Dynavibe and after first test have problem for RPM, at engine throttle stable the reading on the dynavibe had a lot of variations of RPM the angular measurment each time the same but the ups are false and not useful for correction, in the doc they said it's due to false reading with the reflective tape, you succeed with the small one on your picture ? you OP seems to look up no matter ?

[Dorsal]

Yes the system pictured is what I used and was very stable. When I had the tape on the back of the spinner my RPM readings where all over the map. We will probably be trying some more setups this weekend at the Northeast fly-in, will post any interesting results.