Jan 042011
Well, here’s one way to get heavy lifting helicopters: nail a few existing helicopters together. A Piaseki idea shown in a report to the Navy in 1972 involved removing the tail from a more or less stock CH-53D and mating it with another almost stock CH-53D, using a rigid truss-structure to connect the two. Payload was to be up to 18.7 tons.
15 Responses to “Multi-Heli”
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Is there one pilot or two (one I hope).
wouldn’t there be two pilots…one or two maybe in each unit and they
would have to coordinate movements…or else….
Believe it or not, there was also a design study (39-X-11) with the helicopters mated…wait for it…tail to tail. Wouldn’t that be fun.
Whoa, tail to tail. That’s some scary stuff right there. At least they didn’t try to connect them bottom side to bottom side. Of course, would’ve made a hell of a weed wacker.
This looks scary.
Remember the Blimp with 4 helos attached? Tragic ending.
And that relatively small tail rotor turns this entire mating-dragonfly stack? How does that work?
Wait a second,
If each helicopter nominally needs it’s tail rotor to counteract the torque
of the main blades, shouldn’t two main blades need two tail rotors ?
Torque adds and all that.
If they were counter rotating, all bets are off, but that is some serious modification to the original helicopters.
-Gar.
I remember the blimp + 4 attached helicopters. Control problems from having each helicopter with a separate pilot rather than a proper integrated control system. I figure having that blimp in the middle accounts for it working as well as it did with that shoddy control design.
With respect to the tail rotor for torque counteraction. If you’d really pursued this monstrosity I think you’d have built a set of reversed gears for one of the transmissions, probably the forward machine which doesn’t have a tail rotor to worry about.
Barring that, you could modify the tail rotor on the rearward machine. You might do slightly longer blades (so long as they don’t interfere with the main rotor), increase the blade pitch, and increase the gear ratios on the tail rotor drive shaft to spin it faster (or some combination of the the above) to increase the thrust capacity of the tail rotor. Of all of the issues this kludge represents, fixing the tail rotor probably isn’t the worst. Control issues and basic mechanical strength of the overall airframe are probably the biggest nightmares.
Certainly hope it would work better than their Helistat:
http://www.youtube.com/watch?v=_7jENWKgMPY
Yeah, I remember the epic failure that was the Piasecki PA-97. Unfortunately that kluged up nightmare cost a pilot his life.
You certainly have to wonder if any real structural analysis was done on the tubular airframe and if there were any appreciation of the forces that structure needed to endure. I guess a weak airframe and control system/ground effects induced oscillations ultimately did it in.
Just looking at that thing, you just know the pilot couldn’t have had a good feeling when he climbed into the cockpit.
The overall concept itself wasn’t without merit, but the implementation was just horrible in so many ways.
I guess Piasecki had a penchant for wanting to re-purpose/kluge up existing aircraft and other off the wall designs. They did build some workable helicopters back in the 1950’s if memory serves. The “Flying Banana” being the one I remember. Not very familiar with that craft so I don’t know how competent a design it was.
The Flying Banana came out of a period where if a helicopter even flew in a controllable manner it was considered a major success.
The Helistat looked like it was dragging the Eiffel Tower around under it.
If Piasecki wanted to do something like this plan, they should have just taken two entire power/rotor units off of the CH-53 and stuck them on opposite ends of a new fuselage, like a super-Chinook.
And for God’s sake, not side-by-side like that goofy Mil V-12:
http://www.youtube.com/watch?v=kKsWTdjnXiw
How a company that had such a good success record with their helicopters ever decided to design it like that is beyond me; the thing was a throwback to the German Fa 223 “Drache” of WW II.