▁wings ▁and ▁tail plane , ▁causing ▁the ▁air frame ▁to ▁break ▁up ▁in ▁flight . ▁Although ▁the ▁test ▁pil oted ▁successfully ▁ba iled ▁out , ▁with ▁the ▁Berliner - Jo y ce ▁X O J - 1 ▁and ▁V ought ▁X O 4 U - 1 ▁( built ▁to ▁a ▁slightly ▁different ▁specification ) ▁nearly ▁ready ▁for ▁tri als , ▁Bu A er ▁decided ▁to ▁dis continue ▁X OK - 1 ▁development . ▁So le ▁example ▁of ▁Ke yst one - built ▁variant ▁of ▁Bu A ero ▁design ▁no . ▁ 8 6 ▁for ▁a ▁light - weight ▁observation ▁bi plane , ▁ 4 0 ▁of ▁which ▁were ▁built ▁by ▁Berliner - Jo y ce ▁A ircraft ▁as ▁the ▁X O J - 1 ▁or ▁O J - 2 . ▁▁ 1 7 ▁April ▁The ▁second ▁of ▁two ▁West land ▁West bury ▁tw in - engine ▁test ▁bed ▁f ighter ▁pro tot ypes , ▁J 7 7 6 6 , ▁retro f itted ▁with ▁Br istol ▁Jup iter ▁VIII ▁engines ▁with ▁reduction ▁g ear ing , ▁suff ers ▁engine - start ▁accident ▁at ▁Mart les ham ▁He ath ▁this ▁date . ▁With ▁H uck s ▁st arter ▁turning ▁over ▁engine , ▁with ▁the ▁thro tt le ▁accident ally ▁wide ▁open , ▁the ▁aircraft ▁suddenly ▁j umps ▁the ▁ch ock s ▁and ▁coll ides ▁with ▁the ▁H uck s ▁vehicle , ▁being ▁dam aged ▁beyond ▁econom ical ▁repair ▁: stru ck ▁off ▁charge . ▁ 5 ▁May ▁A ▁Royal ▁Air ▁Force ▁Haw ker ▁H