Cotton was able to demonstrate that by removing lead weights it was possible to install cameras with longer focal - length lens in the fuselage .
Lead weights had been installed in the extreme rear fuselage to balance the weight of the constant speed propeller units .
Cotton was able to demonstrate that by removing lead weights , which had been installed in the extreme rear fuselage to balance the weight of the constant speed propeller units , it was possible to install cameras with longer focal - length lens in the fuselage .