Blade tracking changing with head RPM??? any thoughts or fixes?

[OldSchool]

Sirs,

flying a concept 30sx, os32, woodies, byron 15%

I have been having problems getting the engine to run consistantly, so
head speed has not been consistant. No matter what I do with the
links, can't get the blades to track, and today noticed that the high
and low blades will switch (first the one with tracking tape is on
top, then later on th bottom.). I am assuming that the changing head
speed is changing tracking.

Any thoughts?

[Kalm2KAOS]

"OldSchool" <OldSchool@here.com> wrote in message
news:ut0e9vk1uuc2tpqk4n7jl7canc782m9i17@4ax.com...
>
> Sirs,
>
> flying a concept 30sx, os32, woodies, byron 15%
>
> I have been having problems getting the engine to run consistantly, so
> head speed has not been consistant. No matter what I do with the
> links, can't get the blades to track, and today noticed that the high
> and low blades will switch (first the one with tracking tape is on
> top, then later on th bottom.). I am assuming that the changing head
> speed is changing tracking.
>
> Any thoughts?

what about a bent spindle?

--
Paul

I'd rather be flying :-))

[Alan Rait]

Could also be the quality of the woodies

--
Alan

alanDOTrait@btopenworldDOTcom
Replace the DOTS to reply

http://heliweb.users.btopenworld.com/


"Kalm2KAOS" <verytallpaul@btopenworld.com> wrote in message
news:b76rms$m94$1@news8.svr.pol.co.uk...
>
> "OldSchool" <OldSchool@here.com> wrote in message
> news:ut0e9vk1uuc2tpqk4n7jl7canc782m9i17@4ax.com...
> >
> > Sirs,
> >
> > flying a concept 30sx, os32, woodies, byron 15%
> >
> > I have been having problems getting the engine to run consistantly, so
> > head speed has not been consistant. No matter what I do with the
> > links, can't get the blades to track, and today noticed that the high
> > and low blades will switch (first the one with tracking tape is on
> > top, then later on th bottom.). I am assuming that the changing head
> > speed is changing tracking.
> >
> > Any thoughts?
>
> what about a bent spindle?
>
> --
> Paul
>
> I'd rather be flying :-))
>
>

[Beav]

"OldSchool" <OldSchool@here.com> wrote in message
news:ut0e9vk1uuc2tpqk4n7jl7canc782m9i17@4ax.com...
>
> Sirs,
>
> flying a concept 30sx, os32, woodies, byron 15%
>
> I have been having problems getting the engine to run consistantly, so
> head speed has not been consistant. No matter what I do with the
> links, can't get the blades to track, and today noticed that the high
> and low blades will switch (first the one with tracking tape is on
> top, then later on th bottom.). I am assuming that the changing head
> speed is changing tracking.

Suspect the blades, but before you change them, check the scissor arm mixers
directly above the swashplate. They should be smooth to operate, but with NO
slop. If there's any slop, tracking'll be a nightmare.

Some crappy woodies have the C/G too far back and this just makes things
work, so if you change the blades, get something half decent.

One more thing. If the scissor arm mixer base can "rotate" excessively on
the main shaft, that too will add to your problems and to stop it (or reduce
it to within acceptable limits) the part the swash sits on (can't remember
it's part number) should be replaced. They should be replaced every now and
then anyway coz they're only plastic and they DO wear out in time.


--
Beav


Please note my E-mail address is "beavis dot original at ntlworld dot com"
(with the obvious changes)

Beavisland now lives at
www.beavisoriginal.co.uk

[Greg Johnson]

OldSchool <OldSchool@here.com> wrote in message news:<ut0e9vk1uuc2tpqk4n7jl7canc782m9i17@4ax.com>...
> Sirs,
>
> flying a concept 30sx, os32, woodies, byron 15%
>
> I have been having problems getting the engine to run consistantly, so
> head speed has not been consistant. No matter what I do with the
> links, can't get the blades to track, and today noticed that the high
> and low blades will switch (first the one with tracking tape is on
> top, then later on th bottom.). I am assuming that the changing head
> speed is changing tracking.
>
> Any thoughts?

I was having a blade tracking problem that may be related to what you are
seeing: the tracking was varying with the amount of pitch I put in. At
hover, the tracking was perfect. At about zero pitch (i.e., spooling up
the blades while the heli was still on the ground), the tracking was off.

After struggling with this problem for a while, what I finally did
was to make DARN SURE that every link running up to the blade
grips was the same length, and that the arms that the links attach to
were the same distance out from the spindle.

The only link I now use to ensure that the blades track is the one from the
swashplate up to the rocker arm.

Here's what I think was going on for me: I had been playing around with
the links on my rotor head a lot. I think I had a lot of variability all
over the place in the link lengths, arm distance from spindle, etc. (Old-
style Shuttle metal arms.) I would hover the heli (about 6 degrees of
pitch), and then adjust the short link from the rocker arm up to the
blade grip so that the blades tracked correctly. But, it turns out they
were ONLY tracking correctly at that one blade pitch! The asymmetry of the
sequences of links on the two sides was such that, while I could get them
to track at one pitch setting, they would be at different pitch angles at
other pitch settings.

In your case, different head speeds means correspondingly different blade
pitch angles in order to generate 1 helicopter's worth of lift to get to
a hover.

So, here's my shot in the dark: buy new links etc. and make rigidly,
absolutely sure that all of the links, arms, etc. are of the same length
on both sides. Adjust tracking only from the arm that goes up from the
swashplate to the rocker.

My $0.02,

Greg Johnson

Good luck!!

[Carl Farrington]

"Greg Johnson" <gregflies1@yahoo.com> wrote in message
news:8faa960.0304111330.22b50452@posting.google.co m...
> OldSchool <OldSchool@here.com> wrote in message
news:<ut0e9vk1uuc2tpqk4n7jl7canc782m9i17@4ax.com>...
> > Sirs,
> >
> > flying a concept 30sx, os32, woodies, byron 15%
> >
> > I have been having problems getting the engine to run consistantly, so
> > head speed has not been consistant. No matter what I do with the
> > links, can't get the blades to track, and today noticed that the high
> > and low blades will switch (first the one with tracking tape is on
> > top, then later on th bottom.). I am assuming that the changing head
> > speed is changing tracking.
> >
> > Any thoughts?
>
> I was having a blade tracking problem that may be related to what you are
> seeing: the tracking was varying with the amount of pitch I put in. At
> hover, the tracking was perfect. At about zero pitch (i.e., spooling up
> the blades while the heli was still on the ground), the tracking was off.
>
> After struggling with this problem for a while, what I finally did
> was to make DARN SURE that every link running up to the blade
> grips was the same length, and that the arms that the links attach to
> were the same distance out from the spindle.
>
> The only link I now use to ensure that the blades track is the one from
the
> swashplate up to the rocker arm.
>
> Here's what I think was going on for me: I had been playing around with
> the links on my rotor head a lot. I think I had a lot of variability all
> over the place in the link lengths, arm distance from spindle, etc. (Old-
> style Shuttle metal arms.) I would hover the heli (about 6 degrees of
> pitch), and then adjust the short link from the rocker arm up to the
> blade grip so that the blades tracked correctly. But, it turns out they
> were ONLY tracking correctly at that one blade pitch! The asymmetry of
the
> sequences of links on the two sides was such that, while I could get them
> to track at one pitch setting, they would be at different pitch angles at
> other pitch settings.
>
> In your case, different head speeds means correspondingly different blade
> pitch angles in order to generate 1 helicopter's worth of lift to get to
> a hover.
>
> So, here's my shot in the dark: buy new links etc. and make rigidly,
> absolutely sure that all of the links, arms, etc. are of the same length
> on both sides. Adjust tracking only from the arm that goes up from the
> swashplate to the rocker.
>
> My $0.02,
>
> Greg Johnson
>
> Good luck!!

sounds bang on to me. quite an intriguing thing to happen really.

[PETERWOJ]

I had tracking changing with different RPM for following reasons:
1: Bend feathering shaft, think about it and you'll know why
2: Warped wooden blade. One blade gave me more lift than other due to different
geometry and would show out of track, non issue with carbon blades.
3: Locking thrust bearing. Above certain RPM the thrust bearing would lock due
to centrifugal force and would not let the blade move to higher pitch. Easy to
spot as it would show at pretty high RPM's and easy to fix by changing
bearings.
My 02 cents

[sapper]

warped blade was my problem, same as urs!
"Carl Farrington" <carl@000compsup000.net> wrote in message
news:b7a6va$qja$1$830fa7b3@news.demon.co.uk...
>
> "Greg Johnson" <gregflies1@yahoo.com> wrote in message
> news:8faa960.0304111330.22b50452@posting.google.co m...
> > OldSchool <OldSchool@here.com> wrote in message
> news:<ut0e9vk1uuc2tpqk4n7jl7canc782m9i17@4ax.com>...
> > > Sirs,
> > >
> > > flying a concept 30sx, os32, woodies, byron 15%
> > >
> > > I have been having problems getting the engine to run consistantly, so
> > > head speed has not been consistant. No matter what I do with the
> > > links, can't get the blades to track, and today noticed that the high
> > > and low blades will switch (first the one with tracking tape is on
> > > top, then later on th bottom.). I am assuming that the changing head
> > > speed is changing tracking.
> > >
> > > Any thoughts?
> >
> > I was having a blade tracking problem that may be related to what you
are
> > seeing: the tracking was varying with the amount of pitch I put in. At
> > hover, the tracking was perfect. At about zero pitch (i.e., spooling up
> > the blades while the heli was still on the ground), the tracking was
off.
> >
> > After struggling with this problem for a while, what I finally did
> > was to make DARN SURE that every link running up to the blade
> > grips was the same length, and that the arms that the links attach to
> > were the same distance out from the spindle.
> >
> > The only link I now use to ensure that the blades track is the one from
> the
> > swashplate up to the rocker arm.
> >
> > Here's what I think was going on for me: I had been playing around with
> > the links on my rotor head a lot. I think I had a lot of variability
all
> > over the place in the link lengths, arm distance from spindle, etc.
(Old-
> > style Shuttle metal arms.) I would hover the heli (about 6 degrees of
> > pitch), and then adjust the short link from the rocker arm up to the
> > blade grip so that the blades tracked correctly. But, it turns out they
> > were ONLY tracking correctly at that one blade pitch! The asymmetry of
> the
> > sequences of links on the two sides was such that, while I could get
them
> > to track at one pitch setting, they would be at different pitch angles
at
> > other pitch settings.
> >
> > In your case, different head speeds means correspondingly different
blade
> > pitch angles in order to generate 1 helicopter's worth of lift to get to
> > a hover.
> >
> > So, here's my shot in the dark: buy new links etc. and make rigidly,
> > absolutely sure that all of the links, arms, etc. are of the same length
> > on both sides. Adjust tracking only from the arm that goes up from the
> > swashplate to the rocker.
> >
> > My $0.02,
> >
> > Greg Johnson
> >
> > Good luck!!
>
> sounds bang on to me. quite an intriguing thing to happen really.
>
>