Finally figured out a quick way to navigate with Whisky Compass

[Lionheart]

Hey all,

I do not know why, but I could never navigate a circuit (traffic pattern) around an airfield in a plane that didnt have a compass disc. It was the hardest thing for me.

While flying the Dino F-35 lately, having a closed area (top front only) compass reading and the compass reading (digital) in the HUD, it finally occurred to me a super simple way of figuring out your 90 degree turning points...

* Simplify your heading; 115 would be 11 plus a click. 020 would be 2, 350 would be 35, 356 would be 35 plus a click.
* When making a right turn at 90 degrees, add 9 counts to the heading. So... If you are heading 115 Deg, thats 11 plus a click, so 11+9 would be 20 or 200 deg plus a click (205 deg).
* When turning left, (left hand pattern, left turns), you then subtract your 9 points, so 115 deg would be 11-9=2 or 020.
* The hard part (for me) was crossing the 360 threshold when calculating headings until I did it verbally instead of thinking about the equation. For instance; 330 doing a right turn, adding 90 deg to that would be 33+9. With everything starting its loop at 36, with 0 being the next integer or number, you start back at 0 and keep counting.

Example. Right turn; heading 330 (33) would be (adding in mind) 34, 35, 36, 0, 1, 2, 3, 4, 5... So, 33+9=5. What I do is count it off verbally in my mind and cross the 36 point with the next number as zero.

Example 2. Left turn through zero section on the compass. Heading 030, execute LH turn, 90 deg. 3-9= (2, 1, 0, 36, 35, 34, 33, 32, 31). So then, 3-9=310 deg or basic is 31.

Nutshell; counts of 9 with zero being a cross over point (mathmatically, the looping point) for calculating through the N to find your 90 deg turn points...

Works awesome for me. I hope it helps others out that have always had issues figuring out course changes based on 90 deg.



Bill

[SkippyBing]

Bill,

For a slightly simpler method, when you want to make your 90 degree turn, look out the window in the appropriate direction and look for something obvious in the distance that's more or less on the beam. Turn and head towards that, you'll be flying about the right heading. The only maths you now have to do is to make sure you enter downwind on the right heading which of course is the reciprocal of the landing direction, for which you can use the old add 2, minus 2 method.

E.g. Runway direction 100, for the reciprocal add 2 to the hundreds = 300, minus 2 from the tens = 280, the opposite also works so runway 275, minus 2 from the hundreds = 075 plus 2 to the tens = 095.

[jetstreamsky]

The other problem is that IRL the whiskey compass will under read and over read during the turn, remember it as East is least, West is best. In other words making a turn towards the east, the compass will be laggy and if you continue your turn until you see the east heading you will in fact overshoot the required heading whereas while turning to the west, the whiskey compass will be eager to reach the heading early and if you stop the turn at the heading shown you will not have actually reached it. Once you have stopped the turn the whiskey compass will have generally sorted itself out and show the actual magnetic heading, except for any gyroscopic drift. All this is due to cutting the flux lines in the Earths magnetic field with or against the rotation.

[TeaSea]

As part of the instrument test you have to go to partial panel, which really means you go "old school". You use just the wet compass and the turn and bank indicator. Actually works pretty well after you've practiced it a bit.

[Victory103]

When doing compass turns, I was taught this based on my longitude: UNOS=Undershoot North/Overshoot South

[Dangerousdave26]

When I use too much Whiskey I can't turn at all. :icon_lol:

[Lionheart]

When I use too much Whiskey I can't turn at all. :icon_lol:

LOLOL....



I made a mistake in my formula / algorithm. A friend pointed this out to me. 36 'is' zero. So, when crossing 36 on a right turn, go straight to 1, 2, 3, instead of 0, 1, 2, 3.... :S

My oops.

[pilottj]

Yeah I usually use the OSUN method, which is the same as Victory's UNOS. The timed method works great for partial panel stuff too. Standard rate turn will give you 180 degrees in a minute. 30 seconds will give you 90 degrees. 15 seconds for 45 degrees. As a rule of thumb, 3 seconds will give you about 10 degrees. For small course corrections...roll to standard rate...count 1 one thousand, 2 one thousand, 3 onethousand...roll level...your heading should have changed about 10 degrees.

Cheers
TJ

[pbearsailor]

Yeah I usually use the OSUN method, which is the same as Victory's UNOS. The timed method works great for partial panel stuff too. Standard rate turn will give you 180 degrees in a minute. 30 seconds will give you 90 degrees. 15 seconds for 45 degrees. As a rule of thumb, 3 seconds will give you about 10 degrees. For small course corrections...roll to standard rate...count 1 one thousand, 2 one thousand, 3 onethousand...roll level...your heading should have changed about 10 degrees.

Cheers
TJ

TJ has it right--timed turns are really the only way. That's why when you are going to try turns on the compass you should have a watch with a sweep second hand on it. :isadizzy:

If you were in the clouds bouncing around and trying to do turns on the compass, there wouldn't be a good outcome.


cheers,
steve

[SkippyBing]

TJ has it right--timed turns are really the only way. That's why when you are going to try turns on the compass you should have a watch with a sweep second hand on it. :isadizzy:

If you were in the clouds bouncing around and trying to do turns on the compass, there wouldn't be a good outcome.


cheers,
steve

Well the original post was about flying an accurate circuit pattern, if you want to do that with timed turns crack on, but I'd rather be looking out the window.

[TeaSea]

I think pbearsailor is making reference to the idea that if you look out the window all you will see is gray.

I use South leads, North Lags....being a Southerner it's easier for me to remember.

[Lionheart]

I use South leads, North Lags....being a Southerner it's easier for me to remember.

TeaSea,

What is Leads and Lags?

[bstolle]

What is Leads and Lags?

Turning north you have to roll out 30deg before reaching heading 360, turning south you have to turn 30deg past 180deg as the compass swings 30deg further/back at 360 and 180deg

A further error occurs when heading east or west as the compass swings to the north when accelerating and to the south when decelerating.

Nevertheless I highly recommend looking almost exclusively out of the window during a visual pattern as it's unbelievable how many pilots make (unintentional) wrong position reports, enter the pattern from the wrong side etc...
So a sharp lookout in that phase is vital.

[TeaSea]

bstolle's got it. The compass with lead approximately 30 degree's or so when turning to a Southerly direction, and lag's about 30 degree's when heading North. You just have to plan your turns accordingly.

East/West, unless you are making significant speed changes, it really lines up pretty accurately.

[Lionheart]

Ahhh, yes... Roger that. Ive become pretty good at compensating for that.

Many thanks guys.



I was so difficult in the old days for me to figure out my headings. What a mess. I would even put in compass cards and things for my planes because its the only way I could navigate. Finally I can look at that danged Whisky compass and make my turns correctly.



Bill