Luke
All I can say is you are either performing the landing wrong or attempting it in conditions that are too light winds... which means the same thing - not doing it right...
Dont mean to criticize but these are the facts - I am certain the UC and mount is strong enough but one must account for conditions ie grass / runway surface / wind etc.
The most damage I have done to mine in these landings is when doing it in too little wind and I have sanded down the lower corner of the trailing edge of the rudder on the runway..... in the last 10-15 feet in lighter winds it wil soon drop out the sky - you must convert from parachute to harrier landing to normal landing and keep the power on as required.....
sorry if I am telling you something you already know...
Be nice to your 140 !