GLH was a popular 1/2a pylon racer for Cox TD engines and were designed to compete in the AMA 1/2a class. Ace produced a kit of the GLH which utilized their molded foam wings. The Cox Sure Start of today puts out less power than the TD engines making the GLH a little less of a performer when powered with the SS. I have had good luck shrinking the old Pylon racer designs like the GLH by 10% or so when using them with the Cox SS instead of the TD.