Not braking with 9bar sounds strange. Last summer I used 3bar with pulsating valve and still managed to get small flats on the tires. Is the o-ring hard as glass? Actually this wouldn't be bad at all if controllable and symmetrical
btw. My new Hawk is ready for maiden. AUW 11,7kg with just CAT fuelled. Full lights and smoke system on board. Didn't even try to make it light weight... This is to be trainer for the another one and it is heavier with scale gear and all the details. Some 70g of lead on the nose...
/Jyri