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wildbillkelsoe
15th Aug 2017, 08:46
I am not a real pilot and I just fly on PCs. This is my first thread here, so I hope I chose the right sub-forum.

My question revolves around getting wind direction and magnitude at a fixed cruising altitude from observed drifting.

Scenario:

I takeoff from point A, fly for 25 minutes on indicated heading 200°, altimeter is 4500 feet, indicated airspeed 100 knots, following a radio beacon on heading and expecting first visual fix being a red house at 50 nauticals dead ahead. Now after 30 minutes of flying, I notice that the supposed red house is to my right hand at 2 o'clock, about 3 nautical miles, while radio beacon is solid on the 200° bearing. To make matters worse, an updraft hit my plane and the weather briefing flew out the window (non-existent). Now I need to get this calculated. And look, the cloud base rose up to 4000 feet. Now I can't see anything.

In the back of my head, the red house which was supposed to be on my nose, now is on heading 260° at 3 nm after 30 minutes.

How to do it?

DaveReidUK
15th Aug 2017, 12:56
If you haven't done so already, you will find it helps to draw yourself a diagram.

You also need one of those strapped to your knee:

https://i.ebayimg.com/thumbs/images/g/tPYAAOSw0TxZZnXn/s-l225.jpg

:O

Joking aside, "following a radio beacon on heading" would suggest that you might want to review the difference beetween track and heading.

RAT 5
15th Aug 2017, 15:04
Ah; the Dalton computer: or is it? It looks to sophisticated and no where to put the dot with a chinagraph.

sycamore
15th Aug 2017, 15:05
R5,lift the lid...

15th Aug 2017, 15:39
One traditional way is the "Manual Air Plot", but you really need another pair of hands (or a Nav!).

Thusly: you plot your heading and TAS on a map, completely ignoring the effects of wind. The theory then says that after a given amount of time (Ideally an hour or easy fraction thereof) you plot the difference between your actual position and the Air Plot position. The difference will be the wind effect.

Which all proves that "Directional Consultants" entire raison d'ętre depends upon the effects of wind.......

DaveReidUK
15th Aug 2017, 17:10
after a given amount of time (Ideally an hour or easy fraction thereof)

Reminds me of when the RAF was looking for a new trainer (the role that the Tucano eventually filled). The RFP specified that the aircraft should be capable of flying at 240 KTAS.

Apparently the RAF can only navigate when flying at multiples of 60 kts. :O

Yellow Sun
15th Aug 2017, 18:16
Reminds me of when the RAF was looking for a new trainer (the role that the Tucano eventually filled). The RFP specified that the aircraft should be capable of flying at 240 KTAS.

Apparently the RAF can only navigate when flying at multiples of 60 kts. :O

Trouble is, if you wanted to fly 10kts faster you'd have to learn the 1:50 Rule :O

YS

sycamore
15th Aug 2017, 18:31
wildbill,as teeters says,do an `airplot `on some graph paper; you should find that,your ground speed is 97 kts,your drift is 3.5 deg. port,as you are left of track,and computing gives a wind of 260/7kts appx. So ,if you are going 100 miles,you need to alter heading 3.5d stbd,to parallel track,then another 3.5 d to regain track at destination,or, 10.5 d stbd to regain track at about the 75 mile mark.Suggest another 50 rpm and you will regain time as well,as you are 1minute late.....
Whilst the `radio beacon may still be showing 200deg. it is probably a class B bearing which was accurate to about +- 5 deg.Dont forget your fuel checks and time log.....

creweite
15th Aug 2017, 18:45
Hmmm, ADF, I remember those from years ago when I did my IR rating, but does anyone still use what few have not been decommissioned yet when GPS or even VOR is so superior?

oxenos
15th Aug 2017, 21:50
Apparently the RAF can only navigate when flying at multiples of 60 kts.

And all navexes start at 1000 GMT

Rosevidney1
15th Aug 2017, 22:15
Multiples of 60 kts? Pah! Luxury! When I trained on the Hiller 12B a lifetime ago we were lucky to get it up to 55kts. It didn't take a great deal of wind on the nose to demonstrably slow our stately progress across the countryside. Conversely a chuff wind might enable keeping up with a motor car!

izod tester
16th Aug 2017, 09:25
Of course, if you have a navigator, he used to have a drift recorder like this:
https://www.ion.org/museum/item_view.cfm?cid=1&scid=2&iid=3

Herod
16th Aug 2017, 12:11
Driftmeter. There is one available on Flight Sim, as well as a virtual E6B. Suggest the original poster search for them.

Blacksheep
16th Aug 2017, 12:42
The Lancaster was equipped with the Mk.I izod and from photos of the flight compartment (as we techies call the cockpit these days) of PA474, it still is...

http://www.lancaster-archive.com/pic-lanc-interior6.jpg

It's the thing with the big foam rubber ring round the top [a prime reason for Lancaster navigators being prone to having a fine black eye at the end of a trip.]

Herod
16th Aug 2017, 14:55

If this doesn't work, log onto flightsim, go to search file, driftmeter. This is for FS9, but I'm pretty sure it woks in FSX

Airclues
16th Aug 2017, 19:01
ref driftmeter for Flight Sim. here is the link.

I doubt whether wildbillkelsoe will see your reply. Although the above replies are interesting to an aviation historian, I feel that he might have been better asking on the Private Flying forum.

He/she is not accepting private messages so I doubt whether he/she will even see these replies.

Dave

old,not bold
20th Aug 2017, 18:18
I seem to remember that the Twin Pioneers based in Sharjah in the '60s were fitted with a simple drift sight very similar to those mentioned so far. And although I don't remember seeing it, the Shackletons would probably have had one too, wouldn't they?

The Twin Pin one was very easy to use; you just rotated the scope tube until the hairlines lined up with the apparent direction of travel over objects on the ground, and then read off the drift angle from a scale. In hazy conditions, though, it was sometimes difficult to see the ground clearly enough. At night, the moon gave enough light if was big enough, and the occasional Bedu camp fire was useful.

Dan Winterland
21st Aug 2017, 02:21
Apparently the RAF can only navigate when flying at multiples of 60 kts.

Bulldog 120, Gazelle 120, Tucano 240. JP 240 or 300, Hawk 420. It makes the mental maths very easy. The exception to the rules where the few that were multiples of 30 such as the Chippy and Wessex (90) and the Tucano in the Nav training role - 210. This last one was to allow the aircraft to catch up if it was late. The Tucano could only relay manage about 255 at max chat on the flat.

Rossian
21st Aug 2017, 13:40
.....most of the replies suggest you are able to pick out landmarks relative to your track.
Out in the ocean there aren't any landmarks. Thats when you need smoke/flame floats in the water and a drift sight to do the dreaded "three drift wind". Great fun! Not!

The Ancient Mariner

Rosevidney1
21st Aug 2017, 20:43
Dan Winterland
Quote:
Apparently the RAF can only navigate when flying at multiples of 60 kts.
Bulldog 120, Gazelle 120,

Interesting. In the AAC we used to cruise at 135 kts and there was an 'intermediate pitch stop' on the collective lever to achieve this. Hadn't heard of the RAF using 120 kt . What speed did the Navy use on their Chicken Legs, I wonder?

old,not bold
27th Aug 2017, 02:50
Ancient Mariner;

The drift sight I mentioned above could be used over the water so long as you could see the apparent direction of travel and line up the hairlines accordingly. This was normally easy - in daytime - as long as the surface was visible and at least slightly rippled. The rougher the sea the better.

DeanoP
30th Aug 2017, 14:07
Whilst measuring drift angle, it could also be used for a ground speed check by timing, in seconds, an object on the ground, or a wave on the sea transiting from one graticule to the other and using the computer on the LH side. Set height against time to give ground speed. Calculating an accurate ground speed was a problem as height measurement requires an accurate QNH. However a radio altimeter would have solved this problem but were not fitted to my vintage of A/C. The 'Kipper' fleet operating more or less at sea level would have made full use of the drift and groundspeed sight.

On the Hastings a/c we could check the correct alignment of the sight by checking the drift angle along the rivets on the starboard side of the airframe. On the Valetta it was checked by tying string from the pitot tube to the port wheel strut. (and removing before flight!!)

A good bit of kit if you could see the surface.

Black shoe polish on the eye piece was something the Nav had to check before using. Always caused a laugh!

Fareastdriver
31st Aug 2017, 12:47
I used to get my wind from this.

old,not bold
31st Aug 2017, 13:06
Apparently the RAF can only navigate when flying at multiples of 60 kts. And there was me thinking that ground attacks were flown at 420 Kts from cab rank departure point to pull up point just to make it easy for us pongo FACs who had to work out how long it would take, as we huddled in a slit trench in the rain.

Or at least they were when it was Hunters from Chivenor.

nimbev
26th Sep 2017, 23:37
Whilst measuring drift angle, it could also be used for a ground speed check by timing, in seconds, an object on the ground, or a wave on the sea transiting from one graticule to the other and using the computer on the LH side.

The orientation of the graticules on the driftsight assumed that the driftsight was looking below the aircraft. On the Beverley the driftsight was not level in the horizontal plane but tilted slightly above the horizontal so that the side of the aircraft didn't interfere with the view. Hence one could get an accurate drift reading but the groundspeed was unusable. This made navigation even more 'interesting' as we had virtually no navigation aids.