Chili:
I don't know the airfield in question, but I disagree - we do NOT have enough information here to answer definately.
The information we have been provided with seems to indicate that gliding and powered operations are totally seperate, with the powered aircraft operating in this case on the north side of the airfield while the gliders take the south. If this is the case (and I'm not saying it is - I don't know), then a base leg join, to fit in with the segregated power traffic, could well be perfectly acceptable.

Fournicator
That gives me the biggest clue as to what the definite answer is.

Agree! I’ve flown from an aerodrome in the Fens with non radio glider traffic. Gliders don’t always and can’t always do what you expect them to do. As a former Cadet MK 3 rider, I can vouch for this.

Glad to see there is some debate, then. :ok:
Just to clarify some points raised earlier
1) gliders right hand circuit, powered a/c left hand circuit
2) grass airfield, unmarked runways, powered a/c land left of gliders.
3) R/T is "Radio" (sorry - I didn't mention this)
4) First visit (this might be relevant).
Now, I agree with CM that you don't want to get near the gliders. However, if the field is grass, with no clear runway markers, its a bit difficult to see where the runway is (especially if a first visit) - also to orientate yourself to a non-visible runway.
So what would be wrong with an abbreviated overhead join? By this, I mean fly almost overhead at circuit height +1000ft, but remain North of the active runway, away from the glider side. Once near the overhead, the runway becomes visible, as does the glider ground positions and the left/right separation of the circuit traffic. Now, a left turn, still remaining North of the runway, on the "powered" side, towards the runway heading would allow one to orientate oneself to the circuit direction and have a good look at the traffic distribution. A descending left turn onto downwind would insert one nicely into the circuit.
What would be wrong with this approach?
GB

Nothing wrong with this idea, but be aware of the following:

1) Cables drift with wind - there is the possibility that the launch cable could drift across to the powered side, especially if a student / early solo is struggling with the take-offs (you don't say whether the site is winch launch, aerotow or both so I'm thinking worst case scenario here).

2) There may be a local soaring instruction that you don't know about, allowing the gliders to thermal once they're on the powered side, so long as they're above powered circuit height (Have flown somewhere were this was the case). In this case you're going to meet people intent on getting height fairly soon after launch so that they can disappear on cross country tasks / further climb. This won't have a happy outcome :uhoh:

So - how about a slight modification to your idea. Approach the airfield as you've stated, remaining on the powered side. You know the runway direction, so you can work out roughly how that will lie on the field. Identify the airfield from a distance - turn left and descend to circuit height rolling out on a track similar to the runway heading. You won't have identified the runway at this point, but that's not a problem. You will have avoided any gliders operating in scenario (2) above and any cables from scenario (1).

On reaching circuit height - Right turn of 180 degrees to bring you onto a downwind heading at the start of or preferably before the downwind leg. Fly downwind - identify runway, inspect surface and situation, continue with circuit as normal.

a) you really don't want to be overhead as gliders may well be thermalling there and there may be winching
b) don't go near the glider circuit - it could ruin your entire day
c) joining from left base gives you no idea as to what is going on and is almost as bad as joining on a straight in approach
d) if you join downwind you are likely to be parallelling any glider in their circuit so you can get a good view of circuit traffic from glider and power side
e) if you are about to turn base at the same time as a glider, extend downwind or prepare for a go around and let him get on with his landing.

There was a nasty collision at Aston Down not so long ago with tug and glider turning into each other.

The Rules of the Air are quite clear - power gives way to gliders!

Just to add, don't assume that the gliders will always be able to adhere to the left-hand circuit rule. Gliders can get caught out by heavy sink, or be on marginal final glide which doesn't allow them to join the approved circuit.

This time of year that gives the glider a choice between landing in a field full of crop, with probable damage to the aircraft and possible injury to the pilot, or flying a right-hand circuit (or no circuit at all).

You therefore have to assume that gliders may be forced to use any circuit or part thereof, and so need to look out both inside and outside the circuit at all points.

Alarming though this might sound, I know of no collisions between powered a/c and gliders (or between gliders) in the landing phase - there have been collisions near gliding sites, primarily between tugs and gliders, but these seem to occur above circuit height. Having said that, I've seen a number of last minute sightings and consequent manoeuvres, but none which got close enough (in glider pilot terms) to appear dangerous.

The reason for this is, I think, that because there are no definitive rules about where everyone is flying, we all keep a far sharper lookout than in other phases of flight.