"Simon Elliott" Simon at ctsn.co.uk wrote in message:
What prevents those contra-rotating rotors from touching?

Those rotors are quite rigid and fairly far apart, as can be seen he

http://www.airliners.net/open.file/596083/M/

Better yet, have a look at this duckling

http://www.h43-huskie.info/


Best regards

HECTOP
PP-ASEL-IA
http://www.maxho.com
maxho_at_maxho.com