What's up at Hanging Rock? (Pendulous flight instruments)

[Garfly]

 

 

 

[facthunter]

That should all make sense. to you. Also note if the plane is accelerating in a forwards direction the pendulum will be in the same position as if the plane is climbing.

   At night, if there is no horizon, pilot's experience a  feeling of pitch up on climb out as you  accelerate  and counteract it by pitching the plane forward (nose down) and fly into the ground it they are not trained  and forewarned  to rely on the instruments only and not the middle ear based "seat of the pants"  feeling,   Your earthbound body has NO ability to tell up from down  except for the over riding effect of sight. Nev

[Bruce Tuncks]

It's exactly how Einstein figured out relativity. There is NO difference between gravity and inertia...  so what had to give? only our commonsense ideas of space and time. Gravity is the warping of space-time. ( no, I don't really understand it either...  what about gravitons, I wonder) 

BUT in OME's defence, the rock on the string does tell you something in straight and level flight at constant speed. Yes it would need damping to stop the swinging, and then it would tell you slip/skid and Angle of Attack. But wait! we already have that instrument for the sideways stuff. I call it the skid ball and in a glider it is too slow so it is duplicated with a yaw string. If the yaw string blows away, the ball will still be there though.

A fore and aft skid ball would tell you stuff, as long as there was no inertia to worry about.

[facthunter]

I had a plane that had an inclinometer. I think some SUV's have them. An arm runs over a half disc with degrees on it. Aerobatic planes have a structure on the wing tips to align with the horizon. THAT is more reliable.  (or even  a few l Horizontal lines on the windscreen .)  Your AH does all this..Nev

[Bruce Tuncks]

Yep Nev, a brother-in -law had a Pajero with an inclinometer. Sure enough, just when the instrument said, the Pajero rolled.

But I always thought this was a sideways thing and not a fore and aft thing.

 

[facthunter]

Well THAT one was unless he rolled end for end. Nev

[Bruce Tuncks]

Nope, he was negotiating a sideways slope and just when the instrument said, he rolled.

[facthunter]

Back in the 50's they used to say "Buy a VW and Roll your Own" Nev

[Bruce Tuncks]

I wanted a VW beetle in those days but I was too young and poor. I loved the sound of the blower, and yes the rear wheels pivoted around the gearbox so one could tuck under and set off a roll. Only a wimp would worry about this...

[Bruce Tuncks]

The round holdens of the day sure rolled good too. The start of the movie" Sunday too far away" has the hero rolling his holden.

[onetrack]

As regards VW's, it wasn't the rear wheels pivoting around the gearbox that made them roll. It was the major weight imbalance to the rear that made them go from understeer to oversteer in milliseconds, when you pushed them on cornering, or did a quick swerve to avoid something.

 

Modern dual cab utes with a tray that extends the majority of the tray length behind the rear axle, are another vehicle with similarly dangerous handling to VW's, when loaded.

And the worst of the lot is the V8 diesel Landcruiser 70 series, traytop or troop carrier, with the narrow rear axle track. These things are deadly with weight in the rear. 

 

Had a mate travelling with 4 other blokes in a 70 series V8 Troop carrier with the narrow rear axle. They were loaded up with camping gear and a roof rack. They were on a good dirt road, sitting on 100kmh, when it started to rain.

The dirt road had a fair bit of clay in the road base, that turned a bit greasy in sections. They came across a greasy section, and within 20 seconds, the Troop carrier did a bit of a slide, the driver corrected, and it was on its roof instantly, with the driver still trying to figure out what had happened.

Fortunately, all were unhurt, so they climbed out, surveyed the damage (largely panel damage), righted the Troopie with a bit of effort, determined it was still driveable, and off they went again.

They only got 10 kms up the road (driving a lot more slowly) - and they came across an identical Troopie on its roof, as well!