When it came to seat belts and shoulder harness, we were looking for something comparable to what we had used on the prototype. Aircraft Spruce (www.aircraftspruce.com) had exactly what we needed:
Part # Description Price
13-00201 Type 1A seat belt $35.80
13-00601
Type 1A Y-shoulder
harness $43.95
Shoulder Harness Installation
On the prototype, the shoulder harness was anchored to a plate secured by the two bolts that attached the shock plate (G4-2) to the aft side of the mast. This did not seem practical on the new gyro, so an AN4 bolt, spacers, and AN970 fenderwashers were used to mount the anchor end of the harness to the center point of the seat mounting plates, midway between the two lowest set of attachment bolts and centered between the seat mounting rails.
Once achored, the harness routes up the back side of the seat, but your must not simply route it over the back of the seat as shown here. If you do and ever get thrown forward into the harness, it will exert a compression force on your spine that can rupture spinal discs and cause significant injury! This is where the holes, one of which is visible in the photo below, at the top of the seat braces come in!
An AN27 bolt, two AN-960 washers, and a AN4 nylock nut are used, along with a 2-inch piece of 3/8-inch (OD) aluminum tube, to bridge the space between the seat support rails, as shown below:
With the harness strap routed over the aluminum tube, the stress point for the harness is now high enough above our shoulders to avoid spinal compression:
Seat Belt Installation
The fittings at the end of the lap belt are supposed to anchor to the top of the plates that back up the small brackets that anchor the forward end of the drag struts (see arrow below). Unfortunately, with the Brock stick, these brackets severely limit side-to-side stick movement because they interfere with the yoke at the rear of the walking beam stick assembly. It might have been possible to rotate the plates forward to clear the yoke assembly but that solution was unacceptable. I refuse to fly an aircraft where a slight movement of one or both plates would interfere with the primary rotor control system. As an alternative, I opted to mount the belt anchor fittings to sidewalls of the tail boom, about 1.5-inch aft of the attachment point for the seat brace extensions
This was accomplished with an AN-31 bolt, three AN-970 fender washers as spaces on each side between the tail boom and the belt fitting, with an additional AN970 washer on the outside of each fitting:
The final result was a neat and comfortable belt installation.
Although the lap belt looks like it is too far forward, it is perfectly positioned when
you actually sit in the seat!
