## Wednesday, January 18, 2012

### Solve for X

Today someone in an aviation workplace was either amused or insulted, I'm not sure which, by my excitement that he was genuinely using trigonometry for real things. I'm afraid that he may have thought that my excitement and admiration was over the fact that he knew how use trigonometry at all, but really this is just one cool part of a very cool project he is working on.

What do you think he's up to?

Unknown said...

Building a yurt, of course.

Anonymous said...

Looks like he's trying to hard to figure out how much pizza to order...... Dude just go with 5 large, give away the leftovers!! Enjoy with a cold beer!

LT

Wayne Farmer said...

Inclination of solar panels on a roof?

Unknown said...

Why is his 0/360 degree mark facing due west?

Anonymous said...

Good to see it's not just me that needs the "SOHCAHTOA" prompt written out. I learned that 40-odd years ago and hated it at the time, but can't think trig without it in front of me.

Ed said...

«Why is his 0/360 degree mark facing due west?»

Because that's where the Sun is at the equinoxes in the diagram?

I agree with Wayne Farmer, must be something to do with the position of the Sun at different times.

sine - sideways.
cosine - central.

DataPilot said...

The first thought that popped into my head when I looked at the drawing was "Pizza". But other commenters have already covered that possibility, so I'll go with thoughts #2 and #3.

"SOHCAHTOA" - Reminds me of 9th grade math. That was a very long time ago, back when my eyes were good enough to not mind repeatedly scanning the sin/cos/tan charts in the back of the textbook. Electronic calculators existed at that point in time, but they were too expensive for my budget.

Compass rose - Hmm... maybe someone is creating a new IFR approach off of a VOR? Since DME readings are calculated as the hypotenuse of the right triangle where one side is the distance above the VOR, and the other side is the horizontal distance from the VOR.

«Why is his 0/360 degree mark facing due west?»
Maybe they're in Norway, where magnetic variance is extreme, and the magnetic north pole is to the left?

X-av8r said...

Are you doing some nosewheel- roulette calculations again? Or maybe trying to fly an arc around a VOR without a DME? Interesting!

Echojuliet said...

bend allowances for working with aluinum?

more likely to be the previously suggested sun position, but i thought i would throw something out there that i never calculate, even though i work with sheet metal a lot.

Echojuliet said...

or balancing a prop... but we have a computer program for that.

Anonymous said...

I find it interesting that the main divisions of the circle are at 40 degree angles. So the circle is being divided into 9 segments.

Another interesting aspect, is the fact that the segments are rotated 22.5 degrees from 0. Wherever 0 is located in relation to geography. ;)

Carmi said...

Could be flight envelope calculations, with the angles being relative directions of wind.

It could also be an approach envelope for a helicopter to a landing site. The angle would indicate the direction of wind, and the distance from the pole is the wind velocity.

It's been over ten years since I worked a flight-deck, so I'm a little rusty.

Cedarglen said...

To whatever degree you have returned to blogging in this space, Welcome Back! You have been missed. The space is yours and how you choose to use it is, of course entirely at the tips of your ten fingers. When/If you write, I will read and enjoy the moment. If I do not comment on every post, please know that they are appreciated none the less. Best wishes and Happy New Year. -Craig. P.S. As concerns outing bloggers, frankly mam,I don't give a damn who you are. I just enjoy reading your periodic posts. Thank you.

grant said...

The half degree and east west axis might suggest that the diagram is associate with a runway.

The 40 degree segments are calibrated from that 1/2 degree starting point - i.e. the runway.

Perhaps this is a runway obstacle/performace analysis being prepared to establish and IFR departure procedure for a runway with obstacles in various quadrants?... 40 degree segments might be the regulatory requirement ... i.e. must clear the highest obstacle in that segment by 400 feet (or whatever).

Why 40 degrees? We know pilots are allowed up to right/left 10 degree errors due to engine failures etc..., so thats 20. Maybe 20 more are added to provide a buffer to worst case scenario, other instrumentation and measurement errors...

Anyway - that's my guess.

So fun to have some Aviatrix fix today!

DataPilot said...

I have one more wild guess. Might this have something to do with optics? Perhaps polarizing sunglasses for aviators?

Aviatrix, this is why I enjoy your blog so much. You come up with the most intriguing puzzles!

The POAP (The Pissed Off Airline Pilot) said...

Math is easy

Paul B said...

My maths was learnt before SOHCAHTOA became popular here in the UK. My Mnemonic was "Some People Have Curly Brown Hair Till Painted Black"... (P=perpendicular, B=base).

Is someone trying to design a set of door wedges from a tree trunk?

Michael5000 said...

Probably quilt design. That's where ~I~ usually use trig.

majroj said...

Had to repeat every math up to basic geometry, never took trig, but it seems to be a description of a downward spiral or helix? Or up I guess.

leisuresuitwally said...

Nosewheel Roulette 2.0!

Aviatrix said...

I haven't forgotten this. Just trying to get a good picture of the yurt to share.

Anonymous said...

Looks like calcs for a stepper-motor.....