Jonker JS1 Winning US 18m Nationals?

Paul Remde wrote:
Hi,

If I'm reading the online result correctly, it looks like Bill Elliott is
ahead in the US 18m Nationals - flying the Jonker JS-1 Revelation. It is a
very close race though and the contest is not over. But it is cool to see
the underdog (the JS-1) doing well in Bill Elliott's very capable hands!

I am not sure the JS-1 is the underdog, but Elliott certainly is doing very well. It appears that the contest will be won by either him or DJ.

If Elliott does win, the JS-1 will have won all 3 of the National Championships it has entered (twice in South Africa and once in the US).
One wonders whether any other glider has ever had such a record when only a single example of the glider was entered in each contest.