▁cross - section al ▁area ▁and ▁easier ▁se aling ▁of ▁the ▁press ur ized ▁cabin , ▁but ▁it ▁was ▁also ▁known ▁to ▁help ▁with ▁g - force ▁handling . ▁ ▁The ▁ 3 4 6 ▁design ▁was ▁intended ▁to ▁be ▁air - launch ed ▁from ▁the ▁back ▁of ▁a ▁large ▁mother ▁ship ▁aircraft ▁for ▁air ▁launch , ▁the ▁car rier ▁aircraft ▁being ▁the ▁D orn ier ▁Do ▁ 2 1 7 . ▁After ▁launch , ▁the ▁pilot ▁would ▁fire ▁the ▁ 3 4 6 ' s ▁Walter ▁ 5 0 9 B / C ▁tw in - ch am ber ▁" c ru iser " ▁engine ▁to ▁acceler ate ▁to ▁a ▁proposed ▁speed ▁of ▁Mach ▁ 2 . 6 ▁and ▁alt itude ▁of ▁ 3 0 , 5 0 0 ▁meters ▁( 1 0 0 , 0 0 0   ft ). ▁This ▁engine ▁had ▁two ▁ch amb ers ▁— ▁the ▁main ▁comb ust ion ▁chamber ▁as ▁used ▁on ▁the ▁earlier ▁H W K ▁ 5 0 9 A ▁motor ; ▁but ▁capable ▁of ▁just ▁over ▁two ▁short ▁tons ▁( 4 , 4 1 0   l bf ) ▁of ▁thrust ▁at ▁full ▁power ▁( more ▁at ▁alt itude ), ▁and ▁the ▁lower - th rust ▁Mar sch of en ▁thro tt le able ▁chamber ▁of ▁either ▁ 3 0 0   kg ▁( B - version ) ▁or ▁ 4 0 0   kg ▁( C - version ) ▁top ▁thrust ▁levels ▁mounted ▁beneath ▁the ▁main ▁chamber . ▁ ▁After ▁reaching ▁alt