On Thursday, August 13, 2015 at 10:58:24 AM UTC-4, Sean Fidler wrote:
[snip]
By the way, there no speed limit in the U.S. rules.
[snip]

I'm an outsider to this, but in the 2015 rules at http://www.ssa.org/ContestRules , I see:

---QUOTE---
10.8.7 While inside or within 2 miles of any Start Cylinder that has been designated for use by any competition class, pilots are expected to avoid flight at indicated airspeeds greater than 115 mph and to pay particular attention to safe flight near circling sailplanes.
---END QUOTE---

The phrase "...pilots are expected to..." is strangely loose language for a rules document, but it still reads like a speed limit to me.

Cheers,
-Mark Rebuck