Better shoulder Harness Attachment

[avrojockey]

Anyone use an alternative means of attaching shoulder harness? Inertia reels?

Dude I was flying with said a friend of his had a off-field landing in a 7, when the tail cone buckled there was enough slack in the cable that he hit his head on the instrument panel.

I guess he came out of the accident ok, but this got me thinking about alternatives. It would be really nice to have an inertia reel system from seat pan.

 

[RV7A Flyer]

Would an inertial reel be able to take up the slack quickly enough? My understanding was that an inertial reel is primarily to allow the belt to loosen and retract freely during normal use, but then lock up in the event of impact.

 

[rocketman1988]

Anyone use an alternative means of attaching shoulder harness? Inertia reels?

Dude I was flying with said a friend of his had a off-field landing in a 7, when the tail cone buckled there was enough slack in the cable that he hit his head on the instrument panel.

I guess he came out of the accident ok, but this got me thinking about alternatives. It would be really nice to have an inertia reel system from seat pan.

My question would be if the shoulder straps were tight to start with, or were they being worn like most do, comfortably...

Also, Van wrote a good article on "minor" changes to seat belt attachment. It is a good read and details some of the finer points dealing with how seatbelts are attached, and why it is that way.

 

[Roadjunkie1]

Shoulder harness tightness....inertia reels...

My question would be if the shoulder straps were tight to start with, or were they being worn like most do, comfortably...

I have always had the lap belt and shoulder harness fairly tight as that helps keep me in place in the front seat of SuzieQ. Nothing in the cockpit needs the shoulder harness to be loosened to be reached. The snugness helps me to feel more a part of the airplane and adds to the secure feeling I have when we fly. That said, I do have the occasional reason to fly through Wyoming.... I make sure they are tight before I get to Laramie..... SEATBELTS TIGHT is also part of my checklists, including emergency checklist....

I have been in airplanes with the inertia reels and I do not feel like they are holding me in place like a solid belt does. I'm not sure an inertia reel would make the harness any tighter in a rapid forward deceleration than a solid belt.....but I have no data to back that up.....IMHO....

 

[azrv6]

Also, Van wrote a good article on "minor" changes to seat belt attachment. It is a good read and details some of the finer points dealing with how seatbelts are attached, and why it is that way.

Where would one find this article? Thanks.

 

[avrojockey]

Where would one find this article? Thanks.

Yes...very interested in what he said. The current attachment is very robust, I couldn't imagine any part if it failing until I heard of this incident.

The human body can take a lot of lateral force...wonding if you can get near the same protection without extending the seating system so far from the occupant.

 

[wirejock]

Loose belts

I have always had the lap belt and shoulder harness fairly tight as that helps keep me in place in the front seat of SuzieQ. Nothing in the cockpit needs the shoulder harness to be loosened to be reached. The snugness helps me to feel more a part of the airplane and adds to the secure feeling I have when we fly. That said, I do have the occasional reason to fly through Wyoming.... I make sure they are tight before I get to Laramie..... SEATBELTS TIGHT is also part of my checklists, including emergency checklist....

I have been in airplanes with the inertia reels and I do not feel like they are holding me in place like a solid belt does. I'm not sure an inertia reel would make the harness any tighter in a rapid forward deceleration than a solid belt.....but I have no data to back that up.....IMHO....

Driving a race car, the officials said, if they can get a fist under the harness, they wouldn't let you pass onto the track. It got to be such a habit, every straight was an opportunity to yank the harnesses down. Funny how they can always get tighter.
Off roading, I yank the shoulder belt to cinch up.
In our cars, I yank on the belts.
I just don't feel safe, if they're not tight.
Another funny habit, I still pump the brake twice before any use. Had a total failure once. Ever since I hit them twice to make sure they're working.

 

[rocketman1988]

Sport aviation

Where would one find this article? Thanks.

It was an article written by van in sport aviation some years ago, after a builder decided to use inertia reels mounted low near the spar box on a -10. The article was addressing the many mods made to that aircraft, and how some of them actually, in Van’s opinion, were less safe. Not sure the article can be found on the vans site documents.

Out of respect for the builder, I won’t mention his name but search sport aviation for a -10 done up like a Lexus…beautiful airplane…vans response was in the following SA issue.

 

[RV8JD]

"At What Price?"

"At What Price?" by Dick VanGrunsven, Sport Aviation, August 2011, Page 94.

"Mod Masterpiece”, the article on the RV-10 he was critiquing appeared in the June 2011 issue.

 

[StuBob]

My shoulders are higher than the seat back, as is the seat belt attach point. If I make the shoulder belts really tight, it squashes my back down, which isn’t tolerable for long. ISTM the seat back or the harness attach should be a little higher. Or maybe I could fashion some harness guides that would hold it up a couple of inches. It would also keep them in the same place when I took them off, making them easier to find when I get back in.

Has anyone done such a thing? Is there a reason why it’s a bad idea?

 

[EMacGill]

Shouler harnesses have to be designed in accordance with FAA AC 21-34. Note the required angles at the shoulders in Figure 14.

 

[StuBob]

I'm pretty sure most SBS RVs have an excessive downward angle, depicted in that figure as 5 degrees down. It's especially likely in RV7's, where so many people pile cushions and things to get them out of the seat-box hole and let them see forward.

If you attached some sort of guide to the top of the seat, you could make that angle whatever you wanted it to be.

 

[BobTurner]

If you attached some sort of guide to the top of the seat, you could make that angle whatever you wanted it to be.

That assumes, of course, that the seat back could carry the load. A 5g deceleration is very survivable. But for a 200 lb person, that translates to 1000 lbs that must be carried by the restraint system. That’s why Vans cautions against un-engineered modifications.