Dumb Question- Windscreen

[cessna170bdriver]

And as far as where to hang the compass goes... thats what double stick tape is for.

Get a compass that mounts on the glare shield...

[DaveF]

Needing the hole in my panel presently occupied by the compass, I recently bought a new compass, to be mounted at the top of the windshield ... way, way up where it won't obstruct my view out the windshield.

[c170b53]

BR Wrote "You guys make absolutely no sense to me...

Well I'm somewhat shocked because and I really hate to break this to you guys but none of us are making sense to those not owning a plane.
Fortunately there's strength in numbers, enough of us spending money on our planes and spending additional cash to make them into what we individually want. If only one person was doing it...wham, off to a locked white room with a view.

[bigrenna]

delete

[daedaluscan]

At the risk of thread drift, which compass would anyone recommend to mount on a strapless windscreen. Mine is in the panel and is unreliable, maybe the iphone near it or something else but I just dont trust it.

[GAHorn]

Vibration alone will many times impart magnetism to iron/steel objects. (Take a long I-beam or piece of steel and align it N/S and hit it on the end with a hammer a couple dozen times and it will take on the properties of a large compass. Reverse it and hit it an equal number of times and it will neutralize again..and so forth and so on... Electro-Weld on it and watch what happens. (wonder why acetylene welding is so popular on steel-tube airframes.....??? Nonetheless.... steel tube airframes will take on a magnetic flux all their own after a while and need to be degaussed or have the compass swing redone regularly. )

I seem to remember our airplanes vibrate. Anyway... your flight controls, such as the steel-tube "T" and the chains, and yoke-shafts etc etc are ferrous and will influence a compass. (If you sit still and move your flight controls fully as in a pre-flight check, you might see your compass movement.) The trick is to realize your flight controls, while in-flight, rest largely in the neutal postion and you should swing your compass accordingly.
The alternative is to relocate your compass.... and/or.... de-magnetize your control system. (This subject as to removing/demagnetizing, i.e., "degaussing" entire aircraft and/or subsystems has been discussed in these forums previously.)

Ideally, your compass should be swung in-flight...and in a retractible gear airplane with the gear UP...but unfortunately that is impractical. The next-best method is to use an airport compass-rose with your airplane engine running, your usual lights ON (remember, land/taxi lights are only intermittent...don't swing a compass with them "on") and with your tail UP as in level-flight ,also with your flight controls in a neutral position. This can be a tedious process and most folks are satisfied to do this with the tailwheel on the ground.

You can get reasonably close by flying in the mid-west along property lines which align with cardinal directions. (You will need lots of time and have a safety pilot keep an eye out for green planes so you don't run up their tails.)

My own '53 model has it's compass located in it's original position in the panel. I can cause the compass to swing on the ground slightly with control movement, but in the neutral position I was actually able to remove virtually all the meaningful errors from my compass using the compass rose at the local airport and confirming it in-flight with the GPS flying triangular courses.

Hope this line of thought is useful.

[170C]

That Green airplane you refer to George is the one that just passed you

[DaveF]

At the risk of thread drift, which compass would anyone recommend to mount on a strapless windscreen. Mine is in the panel and is unreliable, maybe the iphone near it or something else but I just dont trust it.

I just bought a SIRS compass with the long arm. It was cheaper than an Airpath, and as much as I hated spending even a penny on a whiskey compass, I just didn't want to mess with a used one. The compass comes with a sticky pad for mounting, but I don't know if that's a legal way to mount it. If not I'll make a mount that uses the windshield screws at top center.

Overhead mount

SIRS compass.jpg (42.01 KiB) Viewed 23544 times

[bagarre]

I'm holding my breath until the FAA removes the magnetic compass from the minimum equipment list.
It has to be the most useless instrument in the panel.

[sfarringer]

I'm holding my breath until the FAA removes the magnetic compass from the minimum equipment list.
It has to be the most useless instrument in the panel.

So, what do you set your directional gyro to?
I find the magnetic compass to be a pretty useful instrument.
I use my GPS, but I don't totally rely on it.

[bagarre]

I'm holding my breath until the FAA removes the magnetic compass from the minimum equipment list.
It has to be the most useless instrument in the panel.

So, what do you set your directional gyro to?
I find the magnetic compass to be a pretty useful instrument.
I use my GPS, but I don't totally rely on it.

I don't. I set my destination in of of 5 GPS devices and follow the magenta brick road.

[hilltop170]

The whole GPS constellation can be turned off with the flip of a switch. I witnessed it back in about 1999 when they did a test. One second it's there, the next its gone. Kinda unnerving. I, like most others rely heavily on GPS. I don't use charts on a regular basis but when I go somewhere unfamiliar, I always have chart backup, even if they never get used.

Using the compass? I can't remember the last time, but when the EMP strikes, it will be there when I need it.

[bagarre]

The whole GPS constellation can be turned off with the flip of a switch. I witnessed it back in about 1999 when they did a test. One second it's there, the next its gone. Kinda unnerving. I, like most others rely heavily on GPS. I don't use charts on a regular basis but when I go somewhere unfamiliar, I always have chart backup, even if they never get used.

Using the compass? I can't remember the last time, but when the EMP strikes, it will be there when I need it.

By that same reasoning, the Navy should still have sextants on board with people that know how to use them.

[johneeb]

The whole GPS constellation can be turned off with the flip of a switch. I witnessed it back in about 1999 when they did a test. One second it's there, the next its gone. Kinda unnerving. I, like most others rely heavily on GPS. I don't use charts on a regular basis but when I go somewhere unfamiliar, I always have chart backup, even if they never get used.

Using the compass? I can't remember the last time, but when the EMP strikes, it will be there when I need it.

By that same reasoning, the Navy should still have sextants on board with people that know how to use them.

They don't

[daedaluscan]

Guess I am a dinosaur, I recently sailed across the Pacific and took a sextant and tables with me. Never used it except for fun, but personally I think crossing an ocean without one is foolhardy. I would be absolutely amazed if every Navy ship was not equipped and practiced.