Rotor Blade Management. - Page 3

Birdy2 · 09-09-2007, 10:06 PM

Gday blokes, sorry iv been gon for a bit, i couldnt figure how to git bac on after rotor changed things last time. [good thing i marryed a smart woman, she got me back on.

]

looks like its pretty well covered Mitch.

Only a coupla points.
Waddles touched on the air over the rotor as a break thing.
This is true, to a point.
As you know, the wasa hasa rotor break [ thanc crist] but i dont NEED it. Wen iv landed [ 0 roll] i hold the stick forward and streight away do a 180* to put its ass into the wind. Now, with the stick locked forward ill shut down and hop out. This has the machine resting on the tail wheel. Wotever the disc's AOA is with the stick locked and the machine on the tail wheel, [ bout 5-8* nose down], i can let the blades slow to bout 20rpm before theyll touch the stops, even then they are only 'touchn' the stops. Iv dun this in howling winds and its the same.
IOW, a neg AOA on the disc of between 3 and 6 degrees means 0 lift. 0 lift means no flapn, no matter how strong the wind is.
Relitive blade AS below 30-20 rrpm dont seem to matter, coz at that speed, the teetering is slow n gentle, and they are easy to stop by hand.
Sum people mistakenly think that a blade with 0 AOA is producing 0 lift. Not so. Depending on the [ayssimetrical] foil's shape, it needs to be a little neg to produce 0 lift.
If you hold the blades at a neg AOA of greater than 0 lift, theyll actualy be autorotating, so they wont slow past a certain rrpm.

The other point, wen i gota taxi, fast or slow, i govern everythn with stick position.
If im taxing UW, after iv prespun, bring the engine up to taxying rpm and govern ground speed with stick position. [ faster-forward, slower- back stick] .
Same with DW, only the taxi engine rpm will be lower.
If the tailwind is faster than i wana taxi, then ill hold the stick full forward and govern the GS with breaks.

Wen im prespin'n in a very strong wind, ill be facing it at bout 45* [ wind approchn at 45* to me right.] with the stick full forward AND to the right. [ thisll prevent any lift generated by the 0 AOA thingy.]
Once they are up to bout 30% flyn rpm, gently let the machine roll forward and turn right into the wind, easing the stick to back n center as you go.
And with this sorta wind, its all virtical from there.

Landing is same, in reverse.[obviosly]
Land, no roll, stick full forward, let machine creep round to the left as you ease the stick to the right.
If you have a stick lock, set it so's the locked position has the disc sitn at a little right side down. [3-6*]
DONT turn 180 after touchdown, and have the stick fullforward, coz theyll still flap at a fairly high rpm. If you have the stick fullback, theyll auto and flap like crazy.

Sorry bout the ramblings, this broken wrist is given me the sh1ts.

ill p1ssoff now.

Mitch · 10-09-2007, 10:19 AM

Thanks Birdy.

Heard you had a broken hand, hope it mends up proper. You did go and get it professionally set, didn't you?

Look after yourself.

Have Eric call me if he is about.

Cheers,

Mitch.

Birdy2 · 11-09-2007, 05:43 PM

Russ, ol mate, iv been pondern this comment for a few days;

get a good pre rotator, and a damn good rotor brake system.

Can recall an incidence back some....landed into a ripper of headwinds, huge gusts bashing me as well. Getting the blades to stopped was alarming, "plan B'
took off again, then landed downwind, pulled up, kept the stick fully back and let the blades wind down. Battling with those gusts was interesting to say the least.

So ensure you can spin em up and shut em down real quick.

I cant make head or tail of it, and iv pulled up in sum pretty sh1tty wind too.

russ · 11-09-2007, 07:46 PM

Was me tandem, no stick lock, no prerotator, no rotorbrake......[ last 2 off machine at the time ]

Monsoon time.........strong winds with swerling blasts. Strip had tall timbers both sides.

Landed and as blades wound down o so slow, the swerling gusts were hinging em bad, took off, relanded with tail wind, was then able to lay blades back somewhat as blades slowed down, then let stick go [ no stick lock, so stick would lay full back ] then able to climb on rear seat and hand slow / stop blades.

So having a damn good brakeing system would have made life easier, as also having a good prespinner.
The quicker you can crank em up.........and the quicker you can stop em can lessen some grief.

Your techneek of tippin em sideways into the wind with the swerling gusts about like that day, i think may well get you into some strife.

Laying the disk flat, and cranking on a good brake is my preferred option.

Birdy2 · 11-09-2007, 09:19 PM

Just curious, how fast was the ground speed wen you landed?.

Why didnt you just do a 180 on the ground?

So having a damn good brakeing system would have made life easier, as also having a good prespinner.
The quicker you can crank em up.........and the quicker you can stop em can lessen some grief.
Breaks are like spinners, they dont do anythn for blade managment.
EVERYONE, from student to CFIs should know how to startup, stop blades in any air, without the aid of breaks n spinners.
And if its dun proper, theres no flapn.

Your techneek of tippin em sideways into the wind with the swerling gusts about like that day, i think may well get you into some strife.
Wot?
You think we dont have trees ere, or mountains?

Laying the disk flat, and cranking on a good brake is my preferred option.
Maybe, but its not the correct way, and you be'n an instructer should know better.
Besides, blades will hing more seveirly with the disc flat than they will if they are held proper, no matter how good your break is.

Brian · 12-09-2007, 10:53 AM

You're not the only one confused Birdy with Russ's technique, I have and do land downwind but on a day when its blowing a gale

???......when you can do as Birdy says and just do a 180 degree turn!!

RUSS, explain that one again.

You have probably flown a few Patroney blades Birdy but the bigger diameter Patroneys can be near impossible to start without a pre rotor .Even my 27 ft 6 's are heavy enough to get going. I know, I'm getting to be a bit of a sook.

Graeme · 12-09-2007, 11:16 AM

I know, I'm getting to be a bit of a sook.

A sook maybe Brian, but at least your not limp wristed like one bloke that we all know. ( They say isolation will do that to you).

Graeme.
I have strong wrists, shame about the rest of me.

russ · 12-09-2007, 01:48 PM

Tandem has soft coupled stearing [ springs ] ......useable strip width........skinny, too skinny to do a 180 on the ground unless you hop out and lift the nose and manually carry it around.......that means stick drops to full back [ no stick lock ] while you is out of the cockpit.........you work out the rest. [ just remember we is talking about a big long tandem here, not some p*ssfart single seater that you could turn ona dime ] Soft coupled stearing has this drawback, half decent ground turns are near impossible.........but i like the positives of soft coupled stearing more better. But that's my view, and that's what counts..........to me. If your view differs.....so be it.

Brian · 12-09-2007, 02:50 PM

Ahhh, I see, thanks Russ for that info.

My eyes start to water a little thinking about that downwind landing, say a 30 knot breeze plus approx 10 knots touchdown [assuming big 2 seater] and while I have never tried a 30 knot down wind landing, I can only assume that some forward speed could be needed to keep a things straight. So, a 40 knot touchdown, that should keep the pilot on their toes !

Definitely need a strip thats not dusty as you wouldnt be able to see for a few moments:eek::eek:

russ · 12-09-2007, 03:34 PM

Laying the disk flat, and cranking on a good brake is my preferred option.
Maybe, but its not the correct way, and you be'n an instructer should know better.
Besides, blades will hing more seveirly with the disc flat than they will if they are held proper, no matter how good your break is.

you got areal selective memory dave........you bein an instructor signed off a student recently that "totalled" his machine within weeks, and it was your fault, coz you failed to train him proper with all the ins and outs of low leval perils............nice one there buddy.
Would compare my training to yours any day matey, and i'm yet to fail a student like you just did. Gimey a call, will give you some pointers on proper training.........