View Full Version : Looking for some info on a unique whirly bird I saw today


DrEMHmrk2
24th Jan 2011, 14:39
So, I thought maybe you guys would know what was up with this heli.

I saw a low-flying heli today cruising roughly 45knots pretty much right over I-95 down here in South Florida.

It seemed like a standard helicopter, bigger than an R44, similar to what you would see a news crew flying.

What made it unique, asides from the low flight and speed and being right over I-95 was that it had 2 "outriggers" or pylons on it made of tubular pipe, and at the end of each of these was a white disc-shaped object. I would say the discs were roughly 18 to 24 inches in diameter and maybe 4 inches thick.

At first I thought it was a high-tension power line ship, but I don't think the outriggers were beefy enough to support a person.

Was this some kind of radio reconnaissance bird?

Thanks everyone, i hope my poor description will help!



fijdor
24th Jan 2011, 17:05
Sounds like "magnetic survey" heli or anomaly survey flying low and slow. Depending on the systems he is using, they can look weird.


JD

StAn gelo
24th Jan 2011, 18:55
Like this (http://helicoptersni.fpic.co.uk/p59325105.html) one?

DrEMHmrk2
24th Jan 2011, 19:10
Wow, that's even the same color!

Spot on! What's it for?

DrEMHmrk2
24th Jan 2011, 19:25
I don't know if it's an exact duplicate, because the bird I saw only had the standard numbers on the tail, no additional writing/logo/names I could see.

However the booms are exactly right, as is the size of the bird and the color.

DrEMHmrk2
24th Jan 2011, 19:38
Now I'm wondering what they're doing mapping the magnetic topology in a place like South Florida which is comprised of nearly non-magnetic sedimentary rocks and contains so many buildings, cars and other objects.

Interesting to say the least!

I appreciate all of your sleuthing!

Flying Pencil
24th Jan 2011, 19:48
I think you'll find the kit on the PDG machine is LIDAR.

RVDT
24th Jan 2011, 20:28
More than likely a LIDAR survey.

The pans on the outriggers are the GPS antennas. Using C/A (carrier aided) GPS the accuracy is probably down in the +/- 150 mm range although possibly not in realtime. The GPS data is usually post processed against a fixed base station. The pans under the antennas are to stop reflected signals.

This arrangement would give you very accurate platform orientation in pitch roll and yaw.

There are many different proprietary software algorithms to achieve a GPS position and some C/A units will just not work under a rotor like this one.

rick1128
24th Jan 2011, 21:22
In case no one has told you, the magnetic north pole has moved over 40 nm closer to Russia.

Tru North
24th Jan 2011, 22:04
You've got to watch them Russians!

Sir George Cayley
25th Jan 2011, 19:31
Coke sniffers?

SGC