>
>
>
> Just a thought here. Have you carefully balanced the Warp Drive Prop? An out of balance prop would give the symptoms that you describe. The vibration would seem like a harmonic at certain rpms because it would excite any natural harmonics in the airframe or engine mount.
>
> Rob - Titan IIS, 912ULS, WD Prop
>
Well to be honest, I didn't check the balance myself. My blades did have to go back to Daryl shortly after installing it due to a safety recall they issued on a batch of blades that mine were a part of, and I assume the weights of the blades were checked then.
It was also dead smooth in a static runup (the harmonic only appeared as soon as air really started moving through the prop disk). So that was sort of a poor-man's check.
I did find a very noticeable resonance between the blades and the engine assembly towards the end. Tapping on the end of a blade made the whole plane go "thoooommmm" in a way the IVO and the PF don't when you tap on them. At the time I assumed that was the source of the harmonic and put the PF on.
I still have the prop tho and one day may decide to tinker with it again. A dynamic balance and mounting it directly to the prop flange without the extension are two of the things I might try....
But yeah dynamic balance could be a contributing factor.....
If I could get it to work it would really be nice as the plane really hauls a$$ with the WD on it.....
LS
> --- In Titanaircraft@yahoogroups.com, "ls78705" <lstavenhagen@> wrote:
> >
> >
> >
> > --- In Titanaircraft@yahoogroups.com, "Kimberly Panos" <kimberly@> wrote:
> > >
> > > Lucien,
> > >
> > > One of the Tornados here with no static had the round pop-out vents. You could push the vent open, then rotate it back and forth for almost a 10 MPH change on the ASI, and watch the VSI go crazy, with the altimiter fluctuating as well.
> > >
> > > I think you're the only one I've heard of with a harmonics problem with the WD prop. I know that Ken Korenek has flown one on his 912S for years, and has become almost the exclusive prop that is being installed on all the 912S's at a local RANS dealer/builder here.
> > >
> > > Around here, the mountains keep you prisoner if you're under 10k and want to go anywhere eastbound.
> > >
> > > We use the combo pitot/static that looks similar to the factory Titan setup. We get them from aircraft spruce, then shorten the height. It also requires drilling some small calibration holes in strategic places to calibrate it in the airplane.
> > >
> > > --Kimberly
> > >
> >
> > Hey Kimberly,
> >
> > I spoke to both capn' Bob Perry and Don Trisler about this when I had my WD mounted to the plane, they both use the WD. Bob said he has no trouble and Don said he thought he did have a harmonic but that it wasn't harmful. I think those are the only other 2 SS's that run a 912/WD combo apart from Div whose prop uses WD blades. Go figure...
> >
> > I talked to Daryl at WD about it as well and we pretty much reached the conclusion that I already have about as good a combo as WD can offer already and changes in diameter and extension probably weren't going to do much as far as the harmonic.
> >
> > But it was bad enough to make me nervous about flying the plane long-term with it. You could see a hint of blur on the end of the aileron spades with it and a very very slight blur on the top of the GPS mount in the cabin. Not to mention the hard buzz in the seat.
> >
> > The PF has a completely different resonance which breaks the resonance up. It still gives an audible harmonic on climbout but with no buzzing or vibrating sufaces.
> >
> > There's no more spectacular performer you can get tho. I couldn't believe how fast the plane went at only half throttle.......
> >
> > I love my PF, but I wouldn't use anything else but the WD if it didn't have the harmonic on this particular plane......
> >
> > LS
> >
>
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