Shoulder harness?

[M Towsley]

Re: Shoulder harness?

My Hooker shoulder harness is also attached to the tube in front of the aileron cables and exit through a slit in my interior, which resembles a vinyl headliner in an older vehicle. No reinforcement, and no tears. Adjust the strap/buckle as far up as possible to the mounting tube. This allows the harness to spread wider over your shoulders and lessens the chafing on your neck. I also found at Walmart a seat belt cover that attaches with velcro that I use to pad my neck area. It is made of a thin dark grey velour that matched my lighter grey harness and is relatively unobtrusive. Protects your neck and keeps the belt from getting sweaty and dirty.

Marty
N95275

[gusc]

Re: Shoulder harness?

It doesn't matter if the tube fails or bends, the main thing is that it absorb some of the sudden stop energy rather than have your head absorb all of it.

I know about this after crashing my Stinson and hitting my head on the top edge of the pane. I had no shoulder belts. Although I got a nice gash and was out for a few seconds even a slight absorption of that energy would probably have resulted in no injury at all.

My wife and I had multiple bruises about our bodies but we walked away from it and walked to the ambulance and drove home. Can't ask for more than that.

[AlvinMcIver]

Re: Shoulder harness?

Frank,
My mechanic secured shoulder straps (one on each side) to those diagonal bars. I watched as he consulted the instructions that came with the belts which even indicated the number of times the belt wrapped on itself. If I can find the instructions I will scan and post them.
Alan
As an aside, I take some kidding from my hangar mates for wearing a skateboard helmet from which I cut the sides to fit the head set. That's ok because it has saved me a number of head whacks during those 1000fpm thermal days when the spine is stretched enough to allow the head to contact the cross pieces even though the hips are belted down.

[Frank DeBartolo]

Re: Shoulder harness?

Alan,

Thanks for the info. Are you referring to the Hooker Harness? That is the one that I am thinking about. If it can be attached to the diagonal tubes, it would be great. Does Hooker send instructions with the harnesses?

Thanks again,

Frank

[mhorowit]

Re: Shoulder harness?

It doesn't matter if the tube fails or bends, the main thing is that it absorb some of the sudden stop energy rather than have your head absorb all of it.

A true statement, but it would be nice if _one_ of the items to be repaired after the sudden stop was not that tube. If one could get away without that repair, so much the better. - Mike

[AlvinMcIver]

Re: Shoulder harness?

Frank
As I don't remember the manufacturer, I will have to look at the label on the belts this week end. I checked my logs and the AI did it with a one-time field approval. I have a copy of the 337 and will scan and email it to you if interested, but it looks like he just photocopied the installation instructions, which came with the belts, onto the back of the 337 and sent the 337 to the FSDO for approval.

[flyguy]

Re: Shoulder harness?

I guess the guy in the tow plane was slowed down a bit, but he still pushed the instrument panel in about a foot with a nice round impression of his torso. He didn't get the engine in his lap because he hit the dike with his landing gear. The FAA estimated about 25 g's. The harness and connectors didn't fail.
My implied point was that if you can find a triangulated point with steel behind it in TENSION it will be much stronger than the center of a tube. The problem about a tube center force is that MULTIPLIES the force on the end joints, because the tube doesn't stretch, it just breaks whatever is at the ends.
It would be great if there was a triangulated point we could use on the B models, but I believe, from checking years ago, that the one available is too far off to the side.
Being closer to the end is better, and that may be what we are stuck with.
One of the things I considered back then was triangulating the tube at the anchor point with turnbuckled cables (2) to both sides of the fuselage tubing further back. In a crash the cables would be in tension and very strong, and of course tied to a triangulated point that gives tension strength.
Darryl

[VictorBravo]

Re: Shoulder harness?

Mine were attached to a steel clamp, like an overgrown Adel clamp, which was clamped around the rear cross tube. It adds a lot of extra security in flight for me. but it also shows me that I'd also like to have a lower "submarine strap" like on the acro planes.

In my experience, turbulence can throw you up off the seat. The geometry of the existing lap belt is such that there is not a lot of force holding you down in the seat. The lap belt is at it's best when you are being thrown forward into the panel (yikes). A submarine strap, connecting the lap belt to the floor area under the seat, will provide a much stronger force keeping you from flying up out of the seat.

In my humble opinion, bending the cross tube is the best thing that could happen. If you crash in such a way as to be thrown forward so hard that the shoulder harness bends the middle of the cross tube, then be thankful for the shock absorbing that the steel tube gave you!

I also agree that there might be a better place for the shoulder strap to attach. The best of all places would be Nico-pressed around one of the tube clusters at the lower middle section of the fuselage. The length of cable will also have some give in a crash. And you won't have to cut up your headliner. But trust me, folks, removing the headliner is a nice thing to do in a T-craft. That extra headroom and access to the workings of the airplane is well worth it.

Bill

[Richard Boyer]

Re: Shoulder harness?

I do like my headliner. It vastly improves the interior look of my AC and believe it or not, that makes people that haven't flown before "feel" safer. Also, mine is velcro'd up and is "easy" to get into. Easy is a relative term.....mostly because I have to fuss with it to make sure it is back in the right place. My head does brush the headliner, but I don't notice it with my headphones on.

I do wish I had that "fifth" point on my seatbelt as my head has hit the roof a few times due to turbulence.

If you are really concerned with the strength of that tube (which I'm not), you could always go to a 3 point seatbelt setup like they have in most planes and cars. I believe Hooker sells that setup too.

Richard Boyer
N95791
Georgetown, TX

[adrozell]

Re: Shoulder harness?

Make sure you look at the FAA materials.

http://www.faa.gov/avr/afs/news/harness/seatbelt.htm

It may help with proper installation technique.

[alwaysoar]

Re: Shoulder harness?

These must be Y type shoulder harnesses, so how are the two ends attached to the seat belts? Are they loops the seat belts go through, and if they are, isn't there the possibility the harness could spread if the loops slid along the seat belts, and your body would just push through?

[mhorowit]

Re: Shoulder harness?

I went snooping around looking at harnesses.
The one I saw had metal pieces at the end of each shoulder strap that fit over the seatbelt tang just before the tang was inserted in the seatbelt latch.
I have also seen harnesses with loops at the end which fit over the seatbelt.
I like the first type.
Not expensive - see WagAero.
ONly question - is there enough spacing on the tang to hold the harness hardware when the seatbelt is buckled? I dunno - maybe different seatbelts have longer tangs. - Mike

[AlvinMcIver]

Re: Shoulder harness?

Everyone seems to be fishing around for some answers while Frank and I were communicating off line. In addition to sending a scanned copy of the 337, I sent the following to Frank:

Frank,
Attached are two of the pictures. I'll send three more by second email.
The Mgfr is Davis Restraint Systems, Inc. in Alhambra CA. There was this
number on the label: FDC 7275-74-1-080. If you have any other questions,
let me know.
Alan

The installation of the shoulder belt was easy and didn't cost much at all. I will try and post the pictures which show the attach point on the aircraft and the seat belt.

Alan

Ok, I can't figure out how to post a pictures with this Quick Reply. I'll try some other way.

[AlvinMcIver]

Re: Shoulder harness?

Honey, I shrunk the pictures. Hope they still turn out.

[Guest]

Re: Shoulder harness?

Mine harnesses are attached at the cluster aft of the aileron balance cable by a loop of steel cable wrapped around that cluster.

Some factory airplanes apparently had a fitting welded in back near this point. I installed harnesses that I got out of a wrecked f21 and pretty much duplicated the installation except for replacing the welded fitting witha loop od cable. There used to be an airplane junk yard nearby.

The ends of the cables are looped around the cluster and are bolted to the hardware at the end of the f21 harness. I fabricated the cable loop and before finishing it slide a piece of vinyl tubing over the cable so the cable does not chafe on the airframe.

The f21 harness looks like a regular seat belt with a short piece of cable attached to the metal plate at the airplane end of the belt (that plate that attaches to the aircraft and the seat belt wraps around & thru it).

The harness configuration is single belt over one shoulder (outboard) and the female belt fitting is attached at the same point as the center seat belt anchor (middle of the seat).

Dave