springs located at the end of the torque tube on a Bensen

Butch

Newbie
Joined
Jun 18, 2020
Messages
20
Location
Jackson Ca
Aircraft
Bensen Gyro
Total Flight Time
50 hrs
How should these springs be adjusted and for what purpose? The springs on my Bensen are set to keep the stick pulled back against the seat when I let go of it. Is this correct?
 

Vance

Gyroplane CFI
Joined
Oct 30, 2003
Messages
16,322
Location
Nipomo,California
Aircraft
Givens Predator
Total Flight Time
2400+ in rotorcraft
How should these springs be adjusted and for what purpose? The springs on my Bensen are set to keep the stick pulled back against the seat when I let go of it. Is this correct?
Without pictures it is hard to know so I will take a guess.

Most gyroplanes have a trim mechanism that allows the gyroplane to be trimmed to fly at a particular speed without much stick pressure.

This is often done with a spring.

If there is an adjustment it allows the aircraft to be trimmed for different speeds.

Likely you will need to fly your gyroplane and see what speed it is trimmed for and if you want a different trim speed you make an adjustment.

Depending on how it is done more speed may need more or less spring.
 

Jazzenjohn

Gold Supporter
Joined
Oct 9, 2004
Messages
2,863
Location
Milan Mich.
Aircraft
I've designed, built, and flown 4 different ultralight gyros. Amassing parts for a 2 place now.
Total Flight Time
400+
Like Vance said, the spring is set to fly with little or no pressure at some flying speed. The force you feel holding the stick in the neutral position will lessen as the blades come up to speed. The biggest difference in spring tension has to do with which blades you're using and how much gimble offset you have. Dragon Wings and Sport Rotors for instance, need much more spring tension than Bensen blades. The gimble offset, if reduced, will require less spring tension, but at the expense of reduced stability. The adjustment is usually done on the ground after feeling the sticks reaction in flight. Scott Essex makes a nice spring tensioner that can be adjusted in flight. Most 2 seat gyros have inflight adjustable trim.
 

Doug Riley

Platinum Member
Joined
Jan 11, 2004
Messages
6,402
Caution: If you are a new pilot, have someone more experienced fly your machine and help you adjust the springs. A gyro with springs substantially out of adjustment can be quite challenging and uncomfortable to fly. A brief hop into the air over the runway is enough to allow an experienced pilot to judge how far out of adjustment the springs are, and to take a first pass at dialing them in. It can take several little flights and small changes to get it just right.

The springs normally are set to pull the stick back against the seat when the rotor is stopped, but how HARD they pull is the key issue. Up-down movements of the mast clamp of a fraction of an inch will make a noticeable difference in stick pressure at a given airspeed. The "classic" goal for a Bensen is zero pressure (hands off) at, or just above, the best rate-of-climb speed -- typically 45-50 mph.
 
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