Bent Albert

[Logistics Loader]

assuming of course , someone remembers to lower them...!!!

[DEL Mode]

Just to point out two things.

1. How do you test a cockpit "g" indicator? - Answer you drop it in a vertical axis. Does the RAF have such a test which guarantees the appropriate accuracy? I would ask the question before assuming it is an accurate indication of the actual “g” recorded during a sortie. That is why it is an indicator, and not a gauge.

2. Secondly the 15 or so feet between the gauge and the accelerometer in a Tornado will lead to an error in the readings between the cockpit gauge and the ADR/Fatigue meter. Ever so small, but significant enough.

[rolandpull]

So Chaps,

forgive me for being a techno-phobe, but getting back to the thread:
1. did it undershoot?
2. did it get bent?
3. any piccies?

Anyway G meters are for analysts. Incidentally the first for letters of which happen to be anal!

[Always_broken_in_wilts]

2. Secondly the 15 or so feet between the gauge and the accelerometer in a Tornado will lead to an error in the readings between the cockpit gauge and the ADR/Fatigue meter. Ever so small, but significant enough.

Now if I was a clever chap who built this sort of thing I reckon I could come up with some sort of compensation method to take care of the error mentioned.....just seems like the logical thing to do to me

all spelling mistakes are "df" alcohol induced

[KPax]

To get back to the original post, the ac struck the grass before hitting the threshold and ripping out a couple of threshold lights. Bits of the ac were still being picked up from the threshold the following morning.

[US Herk]

Forgive me if I am speaking out of turn, as I am unfamiliar with Hercs,

Yes, obviously.

how does the fact that the cockpit accelerometer reads 0.2g less than the Airframe accelerometer mean that it is inaccurate??

g limits are typically measured from the intersection of pitch/roll/yaw axes - which usually is near the centre of the wing. I suppose I could concede it is accurate for its placement, but is inaccurate WRT acft limits.

As for your explanation that this is merely the needles "Jumping about", what a load of horsecr4p. If this were the case, according to Newtons laws of gravity, upon sustaining a heavy landing, the needles would be deflected downward under their own weight, thus showing a NEGATIVE reading, as opposed to a 4g positive reading.

Well, you've already been told you're wrong on the pos/neg. What the needles are recording is the spring-weighted movement inside reacting to something it is not intended to measure - impact forces.

Allow me to quote from Mr. Lockheed:

"A Type MA-1 accelerometer, located on teh pilot's instrument panel, gives instantaneous as well as maximum and minimum readings of the g forces exerted on the airplane. The gage scale indicates readings from plus four g's to minus two g's. The maximum and minimum indication needles will remain at highest readings until the push to set button on the gage case is pushed, then they will both retun to plus one g and will again register maximum or minimum readings of g forces until again reset. The accelerometer is designed for inflight use only and does not accurately measure g forces during landing. This instrument is to be used in conjunction with the information on structural limitations in section V."

Had a heavy landing and tried bullsh1t your way out of it before US Herk?

On the contrary - the one time I had a landing that I considered marginally heavy, I immediately turned it in to engineering for inspection. I only considered it marginal based on the fact that two of the emergency exit lights in the rear of the aircraft came on. I would never bullsh1t my way out of anything that could compromise the aircraft integrity & do not appreciate your insinuation that I would.

FWIW - The emergency exit lights in Albert have inertia switches in them that turn them on if subjected to a decelerating force exceeding 2.33 gs. While that isn't a limit anywhere, they don't come on during even firm landings, so I considered it an indicator of something excessive & the prudent thing was to turn it in. Engineering wasn't happy about it, nor was I proud of it, but it was absolutely the correct thing to do.

ROFL..... if the captain can see it behind his knee whilst attempting a tricky manoevere and scanning the primary instruments mhmmmmmmm

Quite good fun during FE whilst OLFing!

The simple cockpit mounted 'G' meters in most British military aircraft are designed to indicate relatively steady state forces. In the event of an impact, cockpit readings will not be an accurate reflection of aircraft structural loads. Strain gauges and/or Fatigue Meters installed near the aircraft CoG are designed to record these forces (strain gauges measure actual deflection of the structure).

YES! Thank you, Blacksheep!

1. How do you test a cockpit "g" indicator? - Answer you drop it in a vertical axis. Does the RAF have such a test which guarantees the appropriate accuracy? I would ask the question before assuming it is an accurate indication of the actual “g” recorded during a sortie. That is why it is an indicator, and not a gauge.

Since my father owns/operates an FAA approved avionics & instrument shop, I can tell you that dropping something, while a good way to measure durability, is a cr4p way to measure a meter's accuracy. Typical cockpit g meters are assembled with springs. Springs can be tested. They also have movements. Movements can be tested. If both are within limits, dropping the g meter can only induce damage & inaccuracy!

I had hoped I would have my Lockheed Tech Manual here at home so I could post a pic, but I don't and have only my aircarft operating manual (quoted above). As I'll be slipping the surlies tomorrow, I'll have a look & see if there's a good piccie of the inner workings of the g meter - as they say, a picture is worth 1000 words and after you see the guts of it, you'll understand why they're not accurate during landing!

I think apologies should be winging there way across the pond round about

Naw, I'm actually on island! Besides, I've got thicker skin than that! :

[Blacksheep]

How do you test a cockpit "g" indicator?

The Standard Serviceability Test (SST) for bench testing a cockpit 'G' meter or more properly an accelerometer, is to rotate it slowly while monitoring the pointer movement for sticking. When on its side the indication is Zero 'G' and when upside down the reading is Minus One 'G'. There is no bench test for the higher figures, though one supposes that factory testing includes the use of a machine that can induce calibrated acceleration forces.

[Hammer Head Too]

Gotta agree with US Herk on this one. Landed many gliders with panel mounted G meters, go over a runway lip, uneven ground, a medium size stone, even a rabbit hole and watch the G meter jump !! 2 or 3 easy