Originally Posted by
Tickle
Purely from theory, in terms of design, cost, performance/handling, maintenance, safety and effect on engine/transmission? Would it improve them or have a negative impact (apart from cost) on the machines?
Comparing the R22 Beta II and the Cabri G2 is a very reasonable example of what might happen. They both use essentially the same engine. First we need to compare performance at an equivalent weight. The limiting factor here is the R22, which at full fuel (168 lbs) can hold 300lbs of people, so say 468lbs total. This would put the Cabri at approx. 1400 lbs equivalent (it can hold a lot more fuel). Looking at the POH for both machines, many of the performance parameters seem nearly equivalent, e.g. cruise speed, etc. However HIGE really falls off in the G2. HIGE is 9500ft in the R22 vs. 7000 in the G2 (standard day).
The other issue is that the Cabri requires 20 or so additional continuous horsepower from the engine compared to the R22 Beta II to obtain the performance that it does. So the derating cannot be as conservative in the G2.
Thus in a putative 3-bladed R44 one might expect to seen HIGE, and possible HOGE, performance fall off, and engine derating changed to a less conservative value.
Of course the real issue is cost, which will rise by a factor of 1.5 for both capital and operating, but you didn't want to discuss that
