Daryl and I just got the Dyna Vibe that has been making the rounds this summer. We went to the hanger and set it up but I don't think we are doing it right. We are getting readings of 3.7 IPS on the Dyna Vibe. The instructional chart you download says that 1.25 IPS is extreme.
We have just over 300 hours on the engine and it has run great. Haven't really noticed any extreme vibrations. We have the 3 bladed Ivo prop. There are indicator tapes across the joints between the three blades. The tapes have never shown any indications of tearing. I would think that if the prop was extremely out of balance they would have torn long before now.
The attached picture shows how we set it up, which is just like the picture we got from Dorsal.
What I am wondering is if we have read the tape charts right. The charts give a tape width for a certain RPM. Is that engine RPM or prop RPM? The rotax we have is geared down about 2.6 to 1 if I remember right.
I had the same thing with mine, it suggest 2.1 initially, and mine never had
any serious vibration. When I added weight and got the IPS reduced I do notice
a big improvement. My guess - Is that that sensor is a little bit whacky, and
the signal output is not linear.
It still works though, and well enough that I was glad to use it.
Actually your posting the high IPS, is good, as I have been a bit worried about
it. However mine static balanced fine in the past, and I could not understand
how the DynaVibe could be saying I had a serious problem. I did get mine down
to .07 and I notice a big difference in flight. Pretty sure it's the sensor output
is the culprit.
I think that maybe we should rebalance the carbs just to eliminate that possibility. The Dynavibe website says not to try to balance the prop with a rough engine. Still, we would have to add an awful lot of weight to get it down as far as the Dynavibe says to.
hi guys, would like to chime in on this as I used the dynavibe about 6 mo. ago on 4 different airplanes and it worked great.as i look at the picture if I am looking at it right it appears that the mount for the prop pick up is an L shape with a along arm forward with the pick up on it. is this arm mounted solid with no movement ? if not it would tend to act like a tuning fork giving very large ips readings. the first thing I would do is remount the pick up securely and take another reading. hope this helps.
Prop Balancing Question
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