suncruiser

Had a fun idea about building a recumbent, sole purpose being speed. ideally a 29" wheel rear end, maybe a 24" single front, with a derailleur style shifting system for the rear. was thinking a nice negative camber for the rear wheels for stability and placing the rider, me, in between them. toying with the idea of disc brakes. just have no real idea how to do this, or where i should start.... anybody have any input on this? anyone else thought of something like this?

Retro Grouch 

If I were building a recumbent with the sole purpose of speed, I don't think that I'd start with the delta trike configuration.

Jeff Wills

Cambered rear wheels will increase rolling resistance. There will be less rolling resistance if they're mounted vertically.

I agree with Retro- if I wanted to build a fast recumbent, I'd start with a two-wheeler.

BlazingPedals

In the HPRA world, the fast trikes seem to be leaning deltas, with front wheel drive and an extremely narrow track (15-17".) They'd still be hard-pressed to keep up with a good highracer or lowracer, though.

BlazingPedals

My advice would be that, if you want something that's fast, look to what's being used in racing now and copy/improve on the fastest designs. Or, you can go off in a totally different direction and design something that hasn't been done before but *should* work. A RWD narrow-track tilter* would fit the bill, if you could figure out how to implement it.
1. Narrow track would keep the frontal area low, which is a major problem with most trikes
2. I'm a big-wheel chauvinist, but if you're trying to keep a small frontal area, using rear tires that stick out above your head would be counter-productive.
3. In some instances, fat tires can be faster than skinny, and where they're sheltered behind the rider might be one of those; but 29-er tires aren't generally designed for low rolling resistance.

*The reason tilters are popular is because the track is so narrow that they'd otherwise tip horribly on turns.