Safe way to check tracking

[KrazyKyle]

I am about to build my first heli. I've heard that it's not a good idea to restrain a running heli (skid separation, blade failure?).

How does one safely check blade tracking? Keep in mind above mentioned rank beginner status (i.e. rock-sold hovering ain't in the immediate future). Obviously, serious eye protection is involved.

[Skiddz]

set up a pitch curve to have 0 pitch throughout the collective stick movement (If you're setting up 0 pitch at mid stick, set all the pitch curve values to 50)

Set the throttle curve up normally (I like 80% at the midpoint in normal mode) and and spool up the heli. Run the collective stick upto mid-stick. You'll get pretty close to full RPM and 0 pitch so the heli shouldn't leave the ground. (Do this with little to no wind and if you've got training gear, put 'em on)

Once it's up to speed, sight along the rotor disc and see if the tips are traveling in the same plane. If you need to make an adjustment, do it to only one blade. Mark one blade and grip as the master and either tweak on that one, or the other one. Don't mess with both as you'll end up chasing the tracking all day.

[liaan]

yes.. ask me.. don't restrain the heli.... don't be near it when blades are spinning.

what i do these days is simply spin the blades up to hover speed to make sure blades in normal position, then drop cyclic a bit ( i run 0/50/100 pitch curve), which gives me slight bit of negative pitch. then from afar check the tracking. if you bench setup your blades correctley , 95% of the time your tracking will be spot on, or half turn off

L:

[gcmsguru]

Don't know how how it'll work out yet, but I've just ordered a stroboscope to be used to check out blade tracking.

A stroboscope, just for any that don't know, is a device which flashes a strobe light ( think camera flash unit ) in a series of accurately timed pulses, and allows adjustment of the flash interval. By setting the flash interval properly it's possible to make a rotating object appear to be still. It's also possible, to determine rpm if the stroboscope is accurately calibrated and has a suitable readout ( either flash timing or directly in rpm ).

By using the 'scope in a dimly lit area, so the process can be done from a safe distance, I hope to be able to "stop" the blades at any given rpm and see what's going on without having to have eyes at blade level.

This sort of thing just may also be useful for diagnosing vibration, main shaft trueness, and other such difficult areas.

We'll see, and I'll post the results if anyone is interested.

[liaan]

that will be very interesting
just gave me idea.. maybe one can use camera with "action photo" (many foto's after each other) to take a "time slice" of the action.... only thing is, there will be now way to adjust the speed of photo's.. but one should be able to pick up any odd movements in other parts.... ie wobble in flybar etc

L:

[DJ NeX]

I think you guys are trying to over complicate this...

1. I just spin the heli a reasonable distance away from me get it approx. 1 ft. in the air.

2. Have a buddy that is next to me get down and spot the offending blade.

3. Set her down, Thottle hold it, buddy whips out handy dandy ball link pliers

4. Buddy makes adjustment then moves a reasonable distance away from the heli

5. Repeat the steps until she's tracking

[BenHeli]

I placed my on the table and tracking the blade while wearing safety glasses and crouching behind the back rest of the dinning chair. Of course, the bird is weighed down with sand bag just in case ... and yet I used to ride the Harley without helmet until the law changed.

[blueviewlaguna]

Originally Posted by gcmsguru

Don't know how how it'll work out yet, but I've just ordered a stroboscope to be used to check out blade tracking.

A stroboscope, just for any that don't know, is a device which flashes a strobe light ( think camera flash unit ) in a series of accurately timed pulses, and allows adjustment of the flash interval. By setting the flash interval properly it's possible to make a rotating object appear to be still. It's also possible, to determine rpm if the stroboscope is accurately calibrated and has a suitable readout ( either flash timing or directly in rpm ).

By using the 'scope in a dimly lit area, so the process can be done from a safe distance, I hope to be able to "stop" the blades at any given rpm and see what's going on without having to have eyes at blade level.

This sort of thing just may also be useful for diagnosing vibration, main shaft trueness, and other such difficult areas.

We'll see, and I'll post the results if anyone is interested.

Let's hear how the strobe idea worked out, sounds interesting.

[fiveoboy01]

The problem I see with the strobe is that you have to be able to see both blades in the same plane at the same time to determine if one is higher than the other. Dunno if you'll be able to do that.

I agree it's not that complicated, pop into a hover and check it or have someone else look at the disc for you.

[Mike_117]

way too much thought going into it.. I just do it myself..
Hover about 10ft away and get to about sight height.( tail slightly offset ) then just rock the elevator back and forth until I get a good read.. land adjust then try again. (using my X marked blade grip for reference).. i figure at that distance.. I'll have enough reaction time to turn my head and close my eyes should a blade come hurling at me...

[archiebald]

I also think there's too much complication in some of the methods.

With my Raptor 50, I set my pitch on the bench using the "master" blade, then I carefully swing the head round 180deg and confirm that the "slave" blade is identical to the master within the limits of half a turn.

Doing this with a set of carbon or glass blades, I make a flight check but I have NEVER had to adjust the tracking for flight.

[leeph]

Originally Posted by liaan

if you bench setup your blades correctley , 95% of the time your tracking will be spot on, or half turn off

Surely most ball links are a one-way only fit - how do you manage to get half a turn out
of a ball link that only goes on one way?

[Mike_117]

Adjust the longer seesaw linkage fro the swash.. it is equal to 1 1/2 turns to the blade grip link.

[mporlier]

Originally Posted by Mike_117

Adjust the longer seesaw linkage fro the swash.. it is equal to 1 1/2 turns to the blade grip link.

Careful we may interpret your "1 1/2 turn" as one AND a half turn. I think you meant one half a turn.

[Mike_117]

Originally Posted by mporlier

Careful we may interpret your "1 1/2 turn" as one AND a half turn. I think you meant one half a turn.

sorry ..1 full turn on the longer link from the swash equates to 1 and 1/2 on the blade link.
(you can then turn 1 full turn back on the small link and it will give you the half turn adjustment you needed)

[mporlier]

Originally Posted by Mike_117

sorry ..1 full turn on the longer link from the swash equates to 1 and 1/2 on the blade link.
(you can then turn 1 full turn back on the small link and it will give you the half turn adjustment you needed)

I think you are wrong or I am confused. I remember Finless saying one turn on the long link= 1/2 turn on the small

[Mike_117]

i know it gives a half adjustment difference to the small link.. it's possible im wrong on the full 1 1/2. i haven't watched the video since last year.

[fiveoboy01]

AFAIK, the ratio is 1 to .5, not 1 to 1.5.

[Mike_117]

Originally Posted by fiveoboy01

AFAIK, the ratio is 1 to .5, not 1 to 1.5.

just confused the wording.