Hi...how do i fly a DME arc ???  Would like to know so i can do the arc on approach plates in planes without an FMC. 

Thanks....Chris

A panel with an RMI(or a moving map GPS    ) is key to a painless arc approach.
With a Radio Magnetic Indicator(the thing that looks like an ADF indicator, if you're not familiar), you follow the needle straight to the station.
When you're within several miles of the arc range(two miles for most jets and one mile for props)begin the 90 degree turn to join the arc. The turn ends with the needle pointing to the wingtip(right or left depending on which direction you're arcing).
Nexus relayed what I think is the best method of performing the procedure(a constant bank turn).
You will hear a lot of people say that "it is not an arc but a series of small turns." These are people who have learned on a standard VOR indicator, in which case the OBS is advanced every ten degrees, making it appear (mechanically) as a small series of turns.
Once established on the arc, you have three elements to monitor: distance from station, proper altitude for the approach segment and lead in radial/final course.

-DME is necessary for the approach. In this "constant bank OR series of turns", bank is increased when distance is too great and decreased when distance is too little. This is the key reason that I think the "bank" method is simpler. Maintain about 3 degrees wing down toward the station increase or decrease two-four degrees, as necessary to maintain your distance.
- Altitude usually is a series of descents based on distance or radial. There can be minimum or mandatory altitudes on an approach.
-When you are close to the final approach course you will be reminded by a lead in radial. This will be established ten degrees from the final approach course. (ie: 360 degree final course(180radial) will have lead-in radials of 170 and/or 190. When you cross this radial you will begin the next 90 degree turn to join the final.
.................make small corrections in bank

     ........practice with no wind first(that's a whole different class all together!) 

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Use the JAC (Jackson Hole) arc as an example.

We'll say that we're
approaching from the South at 13,000 feet. First we'll look at the MSA for the sector. Look at the MSA circle on the right side of the plate. At 13,000 feet, we'll be safe until we're established on the approach. 
I would like to be established before I'm on an approach segment(in real life, ATC would vector you), so I'll make a right turn and join the JAC 143 degree radial and if I'm within 25nm, I'll descend to 12,400(in accordance with the MSA). Set the reciprocal(323 course, so that you have proper sensing) using the OBS.  When the course needle centers, we'll make a left turn to about 320 degrees.  At this point we should be heading toward JAC-VOR on the 143 degree radial.
The DME will be my next focal point. When the DME indicates 17DME(I'll assume you're using a slow aircraft for your practice), I'll start a left turn to join the arc. If you have a heading bug, "life is easy". Most light training aircraft(in the US anyway)don't have a bug.   Set the bug to 233 degrees(a 90 degree left turn). This should put us on the arc over EBACA. Once the DME indicates 16 and the turn is complete we can also descend to the segment altitude of 11,900 feet.
This is where the big difference between VOR and RMI becomes evident. 
Use the OBS to set a 333(or round to 330) course. After the needle centers again, you'll rotate the OBS to indicate 340..then..350 ...and so on....and so on...  If you look on the opposite side of the arc, you'll see R-198 indicated. This is the lead-in radial and tells you that it's time to start another 90 degree turn to join the final course. I can't tell you why there isn't one on the East side(perhaps it has to do with a non-standard descent angle) but I would assume the 358 course(178 degree radial) as my led-in from the East side.
Once you've joined the final course, it's just a standard VOR approach. 


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....with no wind...YES...BUT....the DME is still your primary distance indication. With a wind, the needle may be fore or aft of the 90 degree point and the amount of crab required will change depending on how much arc is travelled for the approach(a constant direction change relative to a fixed wind direction).

Wow, you guys are all WAY over my head!

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Despite the terminology overload, it's really pretty simple. You should try it. It's excellent instrument and situational awareness training.

1-Position the aircraft at Jackson Hole(KJAC) rwy19 and tune the JAC-VOR/115.4 on the No.1 NAV.

2-Takeoff and start a slow turn to the south(yellow line).

3-Climb to at least 12,400'.
..... I also created a map of the route over the MSA circle on the right,  to show can see which sector you'll be in.

4-Once you've climbed to 12,400' or more and at least 25DME-JAC, make a left turn to 060(purple line).

5-Use the OBS(VOR knob)to select the 323degree course.
....This will set  you up to join R-143(orange circle).

This may seem confusing at first. If you look at all of the depicted radials(R-143,167,188,198,209), they orient the pilot FROM the station. You aren't going to fly FROM(radial) the station right? You have to fly TO(course) the station to land don't you? The FINAL COURSE is a perfect illustration of this.
Look at the two green circles.  You must fly inbound on the 188 radial (R-188 ) but you have to set a 008 course (reciprocal)  to fly the approach if you want proper sensing on the VOR because you're heading 008 degrees.
6-When the VOR needle centers, make a left turn and join  R-143(323 course)(blue line).

7-At 17DME(unless you've chosen a fast airplane, then it'll be 18DME)start another left to join the arc over EBACA. Stop the turn when you're heading 230.
......As you were tracking inbound on R-143, you're heading should have been in the neighborhood of 320 degrees. A 90 degree left turn (320-90=230) puts us on a heading of 230.

8-Once you are heading 230 and the DME reads 16 you can descend to the altitude appropriate for this segment(magenta line), which is 11,900'.
...if you've never done this before or feel overwhelmed, I would pause the sim and setup for the next portion or just get your bearings straight
9- Advance the OBS another ten degrees (333 degrees).
.....obviously, if you've been paying attention 343 would be the next progression but R-167(347 degree course) is required to indentify the next segment (brown line) and descent, so I would just jump an additional four degrees(now 14 degrees instead of ten) and set 347 instead of 343.

10-After crossing R-167 descend to 10,500'.

11- Set the course indicator to 358.
....this will identify the 178degree radial(grey line)and let you know that you are only ten degrees from the final approach course.

12-When the needle centers on the 358 degree course, start a 90 degree turn to the right to join the final and set the final course of 008 degrees.

13-Once you're established on the final course, descend to 9,800 feet. Follow the 008 degree course and descend at each segment(DME distance) as the profile view(red box) calls out.

....don't be afraid to pause and check things out or run the sim at a slower speed

lol, I hear ya on the free!  And speaking of Jepp charts, for some reason i just stopped getting my Jepp chart updates in the mail... haven't gotten one since like mid Feb!  Would probably be a good idea to look into that.

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....while on the subject.....I guess it's time for me to update my simulator!        I wanted to give my lesson a test run and found out that '02 still has the old Low Altitude frequency in the database. Ergo, if anyone is trying this at home and using an older version, 108.4 is the old JAC frequency and runway 19 used to be 18. Quote:
  ...that's a tough call.   I tried it with the default Baron and flew the arc at 120kts and two degrees bank and maintained (+/-) .2nm. I can see how maintaining less the two degrees consistent bank might be a bit of a task(flying something slow like a 172).
The problem that I have with the ten and ten technique is that when you transition to larger and faster aircraft, it turns the approach into a sloppy mess. There are a lot of techniques, styles and equipment that I disregarded or bad mouthed as a young instructor, that I later found to be absolutely crucial in  bigger airplanes.
What that method creates is a  continuously fluctuating DME value. If the wind aloft is zero then the cycle can be predictable(on the arc initially, inside the arc and then on the arc again when the next ten degree point is reached).

Because the wind is usually never calm at altitude and the fact that it's relative direction changes throughout the approach means that what is essentially that technique's "acceptable" level of inherent deviation adds to the overall deviation created by dynamic factors. In laymans terms, "you'll be chasing the arc".
Try both techniques in something a little faster like the 737 or Lear45.

Is it just me or does a DME Arc seem like alot of work in just a few minutes/secons 

From setting up the radios and such to the OBS and distances.  I guess in a slow aircraft it would not be as bad but suppose you are in a B1900D how does the pilots set this up in such a short period of time, also what about pilots who are by themselves?

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The key is(and this applies to ANY approach), reviewing the approach and setting up as much of the panel as possible (without disturbing your enroute navigation guidance) as early as possible. In the jets, we generally 'brief the approach' and setup the airplane as much as possible at least 20-30 minutes from the destination. You are correct though, even in a two man cockpit, it is alot of work and rapid-fire situational awareness in a short period of time.