Front shoulder harness attach

[Bcone1381]

I need some help. I don't like the position of the of the factory front shoulder harness attach point (2017 fuselage build) due to risk of injury to the rear seat occupant in an accident.

Photo one is me sitting down with my back on the rear cushion. The the attach point is about 6" form my skull.

Photo two is the factory attach point without my ugly face influencing things.

Photo 3 is my sad design fix...I thought maybe a cushion applied to my fitting would work. It looks pitiful. I'm not good and don't like design, and my design sticks down way too far. If it's too difficult to fit, the rear seat passenger will use have to wear a helmet during takeoff and landing. I bet I spent two or three days on this stupid thing.

Photo 4 is what I have now and what is in Bob's Patrol (photos circa 2017).

You can also see the rear seat shoulder harnesses are wrapped around a fuselage tube. I used a two bar slide like race cars use to wrap the straps around the tubing. I wish I would have thought to try to wrap the front should straps too around the bar that crosses the fuselage above the factory attach fitting.

Is there anything anyone who has a good design fix? I'm past the point of welding anything. A bolt on fix would be nice.




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[Paul Johnston]

Brooks-you could saw off that bracket and grind. Then trapp the rear diagonals with two 1/4” aluminum plates using a 1/4” bolt that’s vertical. Seat belt would be captured with same bolt.

[Paul Johnston]

[Mark Goldberg]

Current production Patrol & LSA kits have a vertical bushing welded into the front of that cluster. With a 5/16" ID. Mark

[Bcone1381]

EVERY time I have a design issue, I over think and over complicate it. I really like your simple fix, Paul. I've been looking at that thing for years, trying to come up with a solution. Now if I can grind it off with out melting holes in my fabric with sparks from the grinder.

[stinger]

Br00ks, my harness mount is placed in the same position as Paul's . Stinger

[S Lathrop]

I have a 4 Place, A model, that is yet to be finished. I struggled with the shoulder harness mounting points.

My back ground is in auto racing, building and driving formula cars. I have been air born and upside down and even have the skid marks on my helmet where it contacted the track surface. So I am a bit anal about safety harness design.

In a race car, I have the should harness mounted so that the straps are horizontal above the shoulders. When you go inverted, the harness does a good keeping you in the seat. In case of a hard frontal impact the harness does not place a downward pressure on the spine as it would if the mounting was below the shoulder. The issue I see and I could not satisfactorily solve was how to mount the shoulder harness low enough to provide proper restraint when inverted.

My current thinking is to have a second shoulder harness that mounts under the seat and passes between the back of the seat and the pilot, over his shoulders and attaches to the shoulder harness where attaches to the lap belt. Another option might be to have the belts that pass between the seat back and the pilot have a loop that the shoulder harness passes through and this would retain the pilot in the seat when inverted..

Just an idea. I am looking for suggestions or thoughts. I have done a short session in an aerobatic plan but I don't remember how the harness was rigged. I do remember that is worked great.

[Light&Sweet]

The lap belt does the yeomen’s duty of keeping you in the seat, including when inverted. Aerobatic aircraft used in competition and airshows will have two lap belts with separate attach points. One of those belts will usually have a ratcheting tensioner. A shoulder harness can help restraint of the upper body in negative-g aerobatic maneuvers, but a shoulder harness in a GA aircraft is present to prevent uncontrolled forward, upper body movement. A lap belt should contact you low on the hips and as tight as you can comfortably make it while in motion.

[Bcone1381]

This is what I came up with. The plates are 4130 steel. The plates sandwich the upper tubing and the bolts make gentle contact with the tubing preventing the sandwich from sliding forward. All bolts will be installed with the nuts up, bolt head facing down to reduce skull penetration risk.
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[500AGL]

I can’t take the time to go into detail right now but I’m also a big proponent of race car restraints, as they are far superior to anything in an aircraft. That industry figured it out a long time ago.
There are good diagrams online of proper restraint angles off shoulders hips and crotch. Which brings up a life saving point from me - if you do any sort of bush or off airport flying, install a 5 or 6 point harness. The 5/6 point is the crotch strap, which I contribute a large part of my current well being to. (If you want to dive into it go to SuperCub.Org and read “A soapbox moment” thread)

Fly an airplane like a Bearhawk that is strong. Install the real deal restraint system. Skip aircraft and go direct to quality race car components. And last, wear your airplane like it’s part of you.

Pb

[Utah-Jay]

Anyone have a link to a retractable shoulder harness 4 point seatbelt?

[robcaldwell]

Do a search on eBay for "Schroth Military Vehicle 4-point Restraint System Seat Belt". You should get many choices.

[Bcone1381]

An example of a Schroth 5 point harness. They use these in race cars....i see more 6 point harnesses though on eBay. I like the 5 point because thats what I've used for 33 years. I used a Schroth two bar slide to wrap the shoulder straps around the fuselage tubing. The crotch strap keeps the center attach mechanism low around the hips on impact. We don't want it rising up into the sternum when we are restrained.
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[500AGL]

Yup, I had the six point Schroth, 3” shoulder straps, it came from a new race car where the driver upgraded to a high end harness for comfort. Excellent harness.