Dme Arcs
 

Hello Everyone :)

I had posted this Q in 2 other forums just few days ago, but sadly
there are no answers up to now except for a single individual who didn't
understand the Q. Here is a copy of the Q below .....basically all am
asking is what's a good practical formula to use from A RADIAL TO AN
ARC & ARC TO A RADIAL and what sort of configuration (flaps/speed) to
be configured prior. ....that's all! I hope I will get an answer on this
forum am sure there are lot's of X 737 drivers who are wroking for
EK,EY,QR, and GF with ample experience to spare to a newbie :cool:

The Q is below;

Hello Folks,

I have question to ask about the formula to calculate (RADIAL TO AN ARC)
and the formula to calculate (AN ARC TO A RADIAL) on B737-200, I am
new on the A/C after few years flying pistons & Turbos. The old formulas
that worked well on the pistons & the Trubo-props. were;

1. TAS X .5% = Radius (take it away from ARC distance or add to it)

2. Radius X 60/DME

I am wondering if these formulas work on a jet or are there other
formulas to use for the jets? I have been recommended to join & fly
the ARC configured with FLAPS 5 + SPEED 180K!!

I would appreciate any replies from 737-200 drivers out there with
demonstrated working formulas to enlighten me with their experience
and any suggestion to join an ARC, or a Radial from a DME arc will also
be well appreciated.

Thanx a Million......and happy flying to all. :) :ok:

Speedy,

Probabley not many answers as the FMS has made life so much easier we have all forgotten some of these basics. No problem with that either as we just don't need to work it out anymore. But from my previous life I think I used this;

Ground speed in nm/min was your radius at 30deg AOB, so for your example of 180kts ground speed (3nm per min) anticipate the arc by 3nm)

For anticipating the radial from an arc, the 1 in 60 rule works. So for 3nm turn radius use this: 3x60/ARC in degrees. So for a 15 mile arc the lead at 180ground speed (3 nm/min) would be 3x60/15= 12deg

This should work regardless if you are in a jet or a hangglider.....as long as the AOB is 30 deg.

As for the best config and speed on the arc that would be one for a 737 driver.

Now my brain hurts.....

FSM

Dme Arc
 

FSM,

Thanks mate for the prompt reply. I will try your advise & see how it
works, sorry didn't mean to hurt your brain :p I know it has been
aumteen years since you last drove manual .....and once you go Auto
you don't want to go back!! the 1/60 rule I was aware of in
calculating ARC to RADIAL as you see in my post, the only thing
the RADIAL to an ARC is calutated a little bit different ....I guess
due to the fast speed upon entry, unlike the pist. & turbs. they
have slower speed for flying the ARC (I mean light Turbs.)

Cheers :) And please don't hurt your brain you will needed to
program the FMS :p

Happy Flying ..... .well appreciated!

Ohhhhh God! Now my brian hurts too. Great answer by the way and I did it just like you explained many many moon ago:}

A320