Heres a link tothe Mig Sweeper setup;
http://library.modelaviation.com/ma/1987/3/mig-sweeperwhich is Greenaway derived series III .
Not discimilar totheese

Bin clowning with drg , 2 in round things , makes fuse just under 36 in,would / will use 60 span , for a 'LongJim'. Jose Modesto plan/ picture .
This actually looks fearfully modern :

and is dimensinally same as the mig . ( predeceeds it ) .
Would think it'd be a good candidate for Igors flap system .
THIS is ANCIENT .
https://images.duckduckgo.com/iu/?u=http%3A%2F%2Fi.imgur.com%2FxRkQiMg.gif&f=1
Apparently techniques have improved since then , though .
post addenum .
Just listening to " Windy Spinners " Tape . At 1:04 he says of Sweepers " & fourth was really Larry Scareinzi lue Angle in disquise ".
( Being the B A is a small .60 ship , he first modern type

one could just start , and finish , there .

. . . . . . )

at the risk of being tedious , we'll put the picture on . Seeing as the cats out of the bag . Who'd of thought , under rated , eh .

was to iconoclastic to omit , borrowed curtosy P.A.M.P.A.