Folding main rotor blade for parking

[Grayforge]

Hi folks,

Question about helicopter storage:

I have a shop that's 35' deep with a door that's 10' wide by 12' tall. I know I can fit some helicopters with semi-rigid rotor systems in, no problem (R22, Rotorway, etc). But if I were to get a helicopter with a 3 blade/fully articulated rotor system, is it relatively easy and safe to either remove one blade or swing a blade around to allow the helicopter to slide into the shop, then (very carefully) reverse the procedure to go flying?

I spoke with an Enstrom rep at Airventure and he said it wouldn't affect tracking or balance on their helicopter.

Thanks!
Russ

 

[JEFF TIPTON]

I would think that require a logbook entry into the airframe mechanic each time the blade is installed.

 

[WaspAir]

It's still not likely to fit, I'm afraid. If you consider the geometry of a three blade system, spaced 120 degrees apart, for a rotor diameter D, if you fold back one blade, the two remaining tips will stick out to the side at least D/4 at minimum width orientation (.87D at max). That means for an approximate 26 foot system (like on a Hughes/Schweizer, about the smallest around) those tips will extend 6.5 feet to the side of the center of the hub. Then you still need half the skid separation (1/2 of about 6.6 feet, or 3.3 feet) plus a ground handling wheel on the other side of the hub. Together, that will pretty much use up your 10 feet of door width.

An Enstrom has more like 32 ft diameter, which means 8 feet for the two blade tips, plus half the gear width.

You could get it narrower by folding two of the three blades, but that will be quite an operation.

I would not recommend removing a blade, and would want to support the folded blades externally. How easy folding might be depends on how the blade is gripped and how the drag link is set up. They are generally not designed with that in mind, excepting Navy choppers with power folding to fit in aircraft carrier elevators.

 

[Grayforge]

Good math! I imagine one could roll the helo in with one remaining blade forward, then rotate it as the helicopter moves in so that the other blade moves inboard. So I think it'd still fit. Something like the crappy artwork below.

The main issue remains "Is it mechanically feasible and would it require special maintenance procedures and inspections?"

 

[WaspAir]

For Standard Airworthiness, I seriously doubt it would fit under owner-performed preventative maintenance.

 

[Grayforge]

You're probably right. I doubt the FAR/AIM says "preventative maintenance includes oil changes, light bulb replacement and main rotor blade removal & replacement."