Driftmeter

[Guest DC3 Pilot]

Greetings,I'm about to install the Driftmeter in my DC-3, and have a question.I came across an article by a WWII B-29 navigator who said that you could determine ground speed with a driftmeter by measuring the time it took an object to pass from the top of the meter to the bottom, provided you knew your exact altitude (didn't say what kind of altitude :-)). Anyone know about this technique? Thanks,Gary

[Dark Moment 0]

Have you read the manual, Gary? Here's what it has to say:"Determining your Ground Speed (GS) and ETA Having measured the course of the groundtrack between A an B on a chart with Mercator projection and having corrected this course for mean magnetic variation enroute to steer your course as per compass, you can determine the distance between A an B using the chart

[Guest DC3 Pilot]

Hi Mark,Right, I did read that. But this fellow was talking about something quite different.What he said was that you could get a groundspeed figure in just a few seconds by measuing the elapsed time an object took to move from the top of the driftmeter to the bottom, provided you knew your exact altitude. I can see how this would be done in theory -- just a little trigonometry -- but not in practice. In theory, you know two sides of a triangle when you know your altitude (it would have to be altitude above ground, not pressure altitude or altimeter reading), and then if you knew the time it took for the object to move from the top of the driftmeter to the bottom you should be able to calculate the angle between the two vertical sides of the triangle. I believe that would be enough data to determine the length of the third side. Having that, you'd know the distance and time, and could compute speed easily (speed = distance / time).Any experience with this method? Or other thoughts?Best,Gary

[Guest DC3 Pilot]

Oops, I got the cart before the horse :-)I downloaded and installed the Driftmeter for my FS2004 M.A.A.M.-SIM DC-3. Didn't encounter any problems. But when I call it up during flight, I get a solid black square instead of the driftmeter itself. I've triple checked the code I copied per the instructions, and I can't see any mistakes there. Anyone able to suggest what I've done wrong, or a fix? I realize this is an AVSIM download and not a M.A.A.M.-SIM product, but I know there are a lot of people on this site who use those downloads so am just taking a shot at getting some help.Many thanks,Gary

[Dark Moment 0]

Here's my own code, Gary. Mine works. Similar?(WindowXX) ......................square brackets, of courseBackground_color=0,0,0 size_mm=284window_size_ratio=1.000 position=7visible=0ident=314window_size= 0.277, 0.277window_pos= 0.197, 0.061gauge00=drift5!drift, 0,0,240,284MarkMark "Dark Moment" BeaumontVP Fleet, DC-3 AirwaysTeam Member, MAAM-SIM[a href=http://www.swiremariners.com/cathayhk.html" target="_blank]http://www.paxship.com/maamlogo2.jpg[/a]

[Guest DC3 Pilot]

Mark,Got it working. Finally just removed all the folders and icons I had installed, deleted the download, and started over. It worked perfectly the first time :-). I must have done something dumb the first time around. Looking forward to learning to use it. BTW, the bubble sextant is now in my navigation arsenal . . . with that download for star positions it's much easier than when I did celestial navigation on a sailboat :-). Great fun using it . . . excellent program . . . just hard sometimes not to use a star with a -40 declination when its azimuth would give such a nifty fix :-).Best,Gary

[Guest DC3 Pilot]

Hi All,I've been playing with the Driftmeter for a few days now, and want to make sure I understand what I'm doing. Any comments on the following will be appreciated.Scenario 1. My true course is 60 degrees with an expected TAS of 140 knots. From talking with pilots who've just been in the area, I'm guessing winds aloft at my chosen altitude to be from the north (360 degrees) at 20 knots. Using my trusty E-6B, I find a wind correction angle of about 7 degrees left, resulting in a new course of 53 degrees. To keep it simple, let's leave magnetic variation out of it. So now I take off, set my bearing at 53 degrees, and am over the ocean but low enough to see whitecaps and use them for the Driftmeter. I discover that I'm drifting about 7 degrees right. My conclusion: I've guessed the wind correction factor exactly, and need make no adjustment now. But if I had discovered I was drifting 10 degrees right, I would adjust my course by 3 degrees left for a new course of 50 degrees.Scenario 2. Same true course and TAS as above. But I have absolutely no information at all about winds aloft. So I take off using an initial course of 60 degrees. Checking the Driftmeter per above, I discover I'm drifting 12 degrees to the right. So I correct by 12 degrees left for a new heading of 48 degrees.Does it sound like I'm making correct use of the Driftmeter?Thanks,Gary

[Dark Moment 0]

>Does it sound like I'm making correct use of the Driftmeter?Near enough, Gary! Although I would think that wave crests are a a little unreliable as fixing aids! They tend to move!Try it over roads, railway lines, that sort of thing. That would be more typical usage, I think. Use the sextant when out of sight of land. We've got to prove to SPOFF that it works! Just for good order's sake, please note that neither the sextant nor driftmeter are MAAM-SIM products, but they work well with MAAM-SIM aircraft. There will be a new release of the incredible Radio Range equipment over at DC-3 Airways, shortly, which will probably find its way into the main libraries eventually; and I have already tailored it to the existing switches for it (which are dummies, to date, but now will work) in the R4D/DC-3 overhead. MarkMark "Dark Moment" BeaumontVP Fleet, DC-3 AirwaysTeam Member, MAAM-SIM[a href=http://www.swiremariners.com/cathayhk.html" target="_blank]http://www.paxship.com/maamlogo2.jpg[/a]