Dusteater,

If speed is your goal, not turning, then you may not need to limit yourself to a delta-wing configuration. The main reasons that high speed aircraft use delta wings are to minimize drag at high mach numbers ( not a problem for you ) and to generate vortex lift at high angles of attack, for maneuvering or landing. If you are able, willing, and allowed by your club to land pretty 'hot', you can probably do better than a delta wing. I have been giving some thought to a really high speed model, and I have been thinking more along the lines of a cruise missile kind of confguration. A minimal fuselage can be used to house most of the junk that Diamond Dust leaves out in the open, and fairly small-area, stubby wings can be placed around the middle of the length, with a fairly conventional vertical and horizontal stabilizer layout. I was thinking about a completely symmetrical 4-fin layout, to complete the cruise missile theme, but that would not be necessary for speed. To reduce drag and weight, the tail surfaces could be mounted on a boom just big enough for strength and to house the control rods. As Ollie pointed out, it is very important to get all the usual crap inside a clean body. Parasite drag, which is the component of drag caused by all the junk, is a huge problem on most models. A small-winged missile with everything inside would be so much cleaner than Diamond Dust that it should not be too hard to beat it for top speed. Landing is a different matter, and might be the reason to go back to a delta wing.

Good luck,

banktoturn