Simple flight computer

[TheBeeKeeper]

Hi folks,

Could anyone tell me the name of the really simple wind correction computer? Small circlular bit of perspex that is only suited to one cruise speed.

My flying club has 100kt ones, but I need to get slower versions, any ideas where to get them from?

Cheers in advance

TBK

[Genghis the Engineer]

For a standard flight computer Pooleys do one with interchangeable inserts, so it'll go down to about 40 knots flying speed.

For a simple wind-vector diagram that you can use for any speed and nothing else, Flylight's A3 flexwing kneeboard incorporates one, if you don't fly flexwings, you could always ask them (01604-494459) if they'll just sell you the insert or do an A4 or A5 version with a similar insert?

G

[The Trolls' Troll]

Have a look at my infinitely configurable system, for both pre-flight and in-flight planning. It always has the answers to any VFR navigation question.
Warning:-1/4-1/2 brain, pre-programmed in the mysterious and rapidly disappearing art of dead-reckoning is required for it's use.
You can teach monkeys to fly, but you can't teach them to navigate.
Website:- Navok.co.uk. If you want one contact [email protected]
The contacts on the web-site don't work as I have given up in disgust and bemusement at the appalling ignorance and abysmal ability in basic trigonometry and mental arithmetic in today's pilots. There's nothing there that a 12-13 yr old schoolboy(40yrs ago) couldn't get his head around.
If you only fly 12-20hrs a year then the benefits of the system will remain a mystery. If however you master it and fly sufficiently frequently that the aircraft becomes part of you, then you'll come to wonder why GPS is ever employed for VFR flight in the British Isles.

[TheBeeKeeper]

Found it!!!!

It's called a Knightson Computer. Simply select the computer that matches the cruise TAS of the aircraft that you fly and it's very simple to use.

www.knightson.org.uk

MODS - I am in no way connected to this company other than having just purchased a computer for myself! I believe it to be a benefit to the GA community! (Luckily they live about 10 minutes down the road from me, so I could pick mine up!)

TBK

[Cricket23]

This sounds an interesting little gizmo.

Beekeeper - I've tried the link that you've posted but it doesn't work. I've also tried .com and .uk as well, but no joy. Any ideas?

[BigEndBob]

When i wer a lad my fust whizz wheel waz made from cardboard.
Bit eazier these daz with futo copiers.

Seem to remember it was made from a Revell Boeing 727 plastic kit cardboard box.

[Three Blades]

If you are happy to use a PDA or programmable calculator then I (and I am sure plenty others) can post the formulae.
Failing that, you could create a simple printed table where you list out the wind speed and relative angle and have the offset angle and the answer. No messing with wizz-wheels or silimar then.

[Cricket23]

Three Blades - Yep I've got a PDA, and would be very grateful for the formulae please.

[Three Blades]

Here you go:

In Excel:

GS=(AS^2+WS^2-2*AS*WS*COS(RADIANS(360-WA+HDGtrue)))^0.5

HDGtrue=TRACK-DEGREES(ASIN(WS/AS*SIN(RADIANS((WA-TRACK-180))))))

Or if you have an HP calculator and want to combine everything together:

TI&H=TRACK/TRACK*INT(DIST*60/(AS^2+WS^2-2*AS*WS*COS(360-WA+TRACK-ASIN(WS/AS*SIN(WA-TRACK-180))))^0.5)+0.001*INT(4+track-ASIN(WS/AS*SIN(WA-TRACK-180)))

GS=INT(DIST*60/INT(TI&H))


GS = Ground Speed
AS = Air Speed
WA = True wind angle
WS = wind speed
HDGtrue = True Heading
Track = True Track
Dist = length of leg to fly
TI&H = single figure output (eg 12.175) of time to fly and heading for leg (eg 12 minutes, 175 degrees)

[hugh flung_dung]

If you learn the very simple techniques based on the Maximum Drift concept you don't need a wizz wheel and you will then be able to plan "unplanned" diversions almost effortlessly in the air without a gadget. They work at any TAS.
Google or ask here if you don't know about them.

HFD

[Cricket23]

Thanks Three Blades / HFD for your helpful comments.

HFD, yes I generally use the Max Drift method when planning diversions, but as low hour flyer I was looking for other aids which might help with the workload in the cockpit when things start to get busy.

[hugh flung_dung]

If you're familiar with max drift (MD) just use the DI as a representation of the sine function.
Imagine a horizontal line from the centre of the DI to the edge, think of this as being of length MD. Turn onto your track, find the wind on the outside of the DI and mentally drop a line straight down onto the MD line so that it divides it into two parts, the proportion of the line between the cente and where the vertical line touches it is the proportion of max drift on that track, turn towards the wind by that fraction of MD and then add variation. Sounds complex but it takes about 10 seconds and very little brain - 100% accurate.

For head/tail wind use the same process but this time the vertical radius of the DI represents the windspeed. Once you have the head/tail wind component subtract/add to your TAS to give groundspeed.
Convert distance and groundspeed to time either by using a scale, by the fact that you will travel 10% of your groundspeed in 6 minutes or by estimates based on easy speeds (120kts: time= 0.5 x distance, 100kts: time =0.6x distance, etc).

This whole thing takes less than a minute, very little brain and is as accurate as a wizz wheel. Once you've practised a little you may never use a wizz wheel again.

HFD