as for the matchbox's? this is all 2nd hand info for me, do a search here in this jet forum, there has been many topics about the matchboxes. about 1 1/2 years aog, i started work on my kangaroo, i saud i was using matchboxes on the elevons, i had many replies saying get rid of them( not reliable) can fail. but is ok to use them on rudders and rudder / nose wheel. as for the exact reason, i am note really sure, but many have said not to use them on control surfaces such as, ailerons, elevons and elevators, so i removed them, then sold the jet to purchase a scale bird

like i has said , all that info is 2nd hand. do a search and read for yourself

mark