View Full Version : Lightning and theodolites

2010-Jul-30, 03:21 PM
I am going back to school this fall and I am feeling kind of nostalgic. Four years ago I dropped out of the Civil Engineering Tech program at school and I am dying to get back.

Although I have changed programs, my favorite memory is of a surveying class. The teacher was great a former police officer turned engineer; He had us all on a first name basis (except his son who was in the class) and he was very relaxed. Except for the one day Martin had a very BAD day...

ECC North Campus is in Williamsville, NY and except for the mound the library sits on, it is completely flat with only a couple of little trees. So Martin would conduct classes outside in the summer session. If you live in the North East, summer is the best time to take Surveying.

On this particular day, the sky was bright blue with some very dark clouds on the horizon. Martin explained that if it rains or worse, if we see lightning, that is it - class would be inside. Fine by me. So I chose to be the poleman and my partner had the theodolite. I figured if it rained, I could run faster with a pole instead of one of the heavy metal theodolites.

Sounds reasonable right?

Let me throw in a detail or two. I am short. I like to tell people I am 5'11" but no one will play that game with me. :) In reality, 5'7" is the largest number I can name without getting a smirk or giggle. This is an important detail. My partner really was 5'11".

The second fact you need to know me and my partner were put together because we were in the same boat. Our wives had both just given birth on the Friday before the class started and after two weeks of work, school and new babies, we were both so short on sleep our waist size and IQ were the same number.

Our task was pretty simple. To save time my partner set the tripod to my height and let me "shoot" first.

So, not only didn't I have to carry the beast of the theodolite and its box outside, I got to go first because he thought it was easier to lean down. I had my figures documented and took my position for his "shoot" in record time. Which was good because the storm clouds were rolling. Again I was in the place that I wanted to be, closer to the building and holding the lightest piece of equipment and my partner would be allowed to use my figures for his part of the project if it rained. All was good.

So there I am holding this ridiculously long metal pole when the whole sky lights up like a flash bulb. This incredibly bright bolt of lightning traced a line from the clouds to ground and burned into my retinas. The clap of thunder was equally amazing, I could feel it.

Lightning and thunder is impressive and powerful. It crosses that impressive line and goes to right to horrifying when you are holding an extend-able metal pole. Although I was actually too terrified to run, I did drop the pole and started to count fingers and toes. My partner threw himself on his back and crab-walked away from the big metal tripod and theodolite.

Just as the first splatters of rain came down I heard Martin, our teacher bellow "RUN!"

Between the thunderclap and rain my partner was confused and ran towards the parking lot. I chased after him yelling "Inside!", waving wildly at the building. I had run all the way back to his set up before he heard me. I waited to make sure he was coming back, and made my second huge mistake.

I picked up the theodolite and threw it in its case and sprinted for the building. I figured that it was expensive despite being 20 years old and in its wooden box what was the danger?

I caught up with Martin. He looked back at me and howled "DROP IT! DROP IT! DROP IT!" I thought "No way", and kept running. When he saw that I wasn't going to drop it, he spun and sprinted the distance to the doors and held them open. I slid through the door and pulled open the inner door.

Martin was chanting "Oh-gawd-oh-gawd-oh-gawd!" at this point and when I turned I saw why.

My partner watched me box up the theodolite and run for it. So he stopped and threw the tripod over one shoulder and the pole over the other. His bouncing run had the legs of the tripod and the pole at full extension and he couldn't run very fast like that.

I used the theodolite to prop open the inner door and started to run back outside yelling "Drop it!" but Martin grabbed me. My partner made it through the outer door, but the pole was too long to make it. At maximum length it was taller than the building. He slipped and slid through the second door on his butt. He recovered and tried to drag the pole through both sets of doors. Martin had let the outer door close on the pole and my partner had knocked the theodolite case away from the second door trapping the pole.

Martin quietly told us "Come on", but my partner was determined to get that pole in the building so we left him struggling with the doors. Martin spent the next two hours in silence watching the rain come down. Questions were answered with quiet yes's and no's. He didn't even assign homework that night.

Martin will always be my favorite teacher. I have so many "fun" memories of that class.


2010-Aug-04, 01:30 AM
During July of this year, I was sitting on the front porch with my house dog, She-She, smoking my evening cigar. We were experiencing a fierce squall, or what the weather department calls an 'isolated thunderstorm'. All of a sudden, behind the house across the street from me, a bright lightning bolt struck and I heard the tremendous clap of thunder immediately after the lightning bolt. Since sound travels around 740fps, and the thunder was with the lightning, the bolt struck a little over 200yds away. As far as I know that's as close as I've ever been to a lightning strike. I took She-She inside and we stayed inside.

2010-Aug-05, 07:58 AM
Up until the early 1970s, Washington State College (now Washington State University) required all engineers (even the electrical engineers) to attend a summer surveying camp. My father (a CE) attended the camp in the early 1950s but by the time I started college, the camp was no longer a requirement for EEs. I suppose I am the lesser for that. My father has told me some mighty tall tales of his summer camps (CEs back then went to camp multiple times).

I did borrow a theodolite from work, once, to sight a fence line between my property and my next-door neighbor, as we had to build a new fence to replace the old rotted fence. That line still holds in wood after 15 years.

2010-Aug-07, 03:01 AM
Lol, Solfe - I'm glad you both were ok! Your story was electrifying, to say the least!

A hiker here in Colorado was recently struck by lightening and was found later by other hikers. Fortunately, he lived as well, though most hikers struck by lightening around here do not live.

I have a question about modern transits, having watched a team survey for some future roads at a base in Iraq. They were using transits with built-in differential GPS capability (a "total station"), and I asked them what they used to pin-point the location of the differential GPS , and they said it was a time-averaged WAAS system, but that couldn't have been, as WAAS coverage does not extend to Iraq! (It's only over the US (http://en.wikipedia.org/wiki/File:WAAS_service_area.png)) Furthermore, WAAS' accuracy has been repeatedly measured as being good down to about 0.9 m / 1.3 m (horizontal/vertical), which isn't good enough to use as coordinates for the beacon on the base. I thought perhaps they used EGNOS, but I don't think that service covers Iraq, either, as its nearest ground RIMS is in Turkey.

So how did they measure the precise location of either the referenced land survey mark or the base beacon?

2010-Aug-07, 09:27 PM
We need a real know-it-all, to answer Mugaliens' question. Got any in the house? grin.

2010-Aug-11, 09:12 PM
They may have been using a commercial differential GPS service like OmniSTAR (http://www.omnistar.com/index.html), which claims both near-worldwide coverage, and a 2-sigma horizontal CEP of less than 20 cm for their "XP" service.

2010-Aug-12, 07:32 AM
They were probably using "real time kinematic differential gps".

How to do a GPS survey to centimetre accuracy (http://www.geod.nrcan.gc.ca/edu/rtk_e.php)

2010-Aug-12, 06:13 PM
We were at Nellis Airforce Base outside of Las Vegas educating the Air Force on just how nasty an elite Navy Tomcat outfit is as an opfor. On these little side trips away from our home base, which was then NAS Mirimar just north of Sandy Eggo, we only brought the guys who had time in and were really good at their jobs, due to the near proximity of all the fine entertainments Las Vegas had to offer.

That was the trip then Lt. Stufflebeem pulled a 12 gee turn and bent the airplane. Kinda funny if it wasn't you who did it. Couldn't get the wings folded back in, an important feature in sweep wing aircraft, and when he landed the wing tips were drooping nearly four feet lower than normal and the bird was just gushing fuel from both its wing roots. Airframes had the bird flying again before we left. *I* would have thought depot level repairs, at the least. They had to replace the titanium I-beam that holds the wings on. (I watched some of that. An I-beam made of titanium is rather pretty in the right lighting.)

But man, we had a bad thing happen.

Weather was hot all day and when this storm blew in and the rain fell, the heat of the concrete runway re-evaporated the rain before it hit the ground. We were walking around the flightline, wet from the shoulders up only, as we remarked on one of the oddest rainstorms most of us have ever seen.

That's when three or four of the senior flightline guys, who actually knew what the hell was about to happen, ran out of the hanger and tried to alert and sherpard in a whole flightline full of working people who were ignorant of the dangers now bearing down on us. I'm first alerted when the guy I'm talking to points and I see a couple of guys running out of the hanger like somethings on fire, so I look to see if indeed, something is on fire.

Turned out to be the sky.

At the end of the runway was a line of clouds putting down so many lightening bolts it looked like they were walking on insect legs made of electricity. And that's when you look up and see all those fat black clouds that had held their fire until now and are right overhead and you think, "Hmmm, I'm standing on a flat concrete runway full of metal airplanes with tails thirtyodd feet tall held to the ground by twelve metal chains. Wonder what's going on in the hanger?"

And we all got inside and closed the hanger doors to about ten feet wide as it stormed like hell outside.

We were taking muster when the guy who started the whole alarm, a guy who had been promoted out of the line shack after eight years in and was now in airframes, staggered in through the space between the hanger doors. His hair, fly and shoes were smoking dispite the rain and he collapsed in front of the formation, trying to tell us about the other victims.

One of the planecaptains was in the middle of one of their more elaborate inspections and had a lot of panels open when the Airframes guy ran up to warn but the both knew you can't leave all the cowlings open and such so not only those two, but four other plane captains, or former plane captains were helping close up the bird when that plane was struck by a large bolt. Four weren't even in direct contact with the aircraft.

None of the victims were able to return to active duty.

That was a monsterous hit for my outfit. I saw the Airframes guy about four months later talking to the Skipper. He was paralyzed on the left side, but improving to partail. He was being put in for a commendation.