Shoulder harness

[jimbrain]

Does anyone have a suggestion on the best way to carve a slot in the former over the rear spar carrythrough for the harness strap without nicking the square tube? Headliner is in place and zipper is about six inches behind spar.
Thanks, Jim

[EDGEFLY]

Jim,
I don't have an explicit answer to your question although I do know that Bill Pancake has developed a " restraining " system which presumably solves the Shoulder harness problem for Chiefs. I have seen it posted somewhere, perhaps on the fAA forum. I have not proceeded with a shoulder harness installation on my Chief since I have been unable to identify an acceptable "Y" configuration harness to use. Could you share with us your harness choice and how you plan to integrate or replace the existing seat belts ?


Dale

[John Baker]

I had success using an angle drill/driver to drill a hole at each end, then using a Fein Multimaster to cut the area between the holes to complete the slot. Now that the patent on the Fein has expired, there are numerous less expensive competitors. A handy tool for cutting in tight spaces.

[jimbrain]

Dale and John,
Third try answering your posts. Ipad keeps locking up, so don't know what you will get.
John, thanks for the suggestion. My son has one of the knock offs.

Dale, I plan to order the 3A "Y" type from spruce with the sewn in loops. That way I won't have to replace my seat belts, and I believe the loops will be more comfortable for me. I have used the metel to metal which join in the very middle and was not too happy. If I am not happy with these I am only out about $100 for the pair,and can try something else. I will anchor them to the rear spar carry through by looping the strap around the square bar.

Thanks for both your replies.
Jim

[Richard Murray]

Jim

Is this the harness you are thinking of?
http://www.aircraftspruce.com/catalog/a ... ness3a.php

Richard

[jimbrain]

Richard,
Yes, that is the one. The image at the top shows metal blades like the 3B, but the description and drawing below show sewn loops. Guess I better check before I order.

Dale,
I found a combination in the Spruce catalog I think will work as a metal to metal set. Be sure that both sides of the belt are adjustable at the buckle.

Jim

[EDGEFLY]

Jim,

I'm not sure what you are looking at for metal contacts but I have looked at the Air Spruce line-up and didn't find what I thought I wanted. I have seen somewhere a four way buckling arrangement which had a single point disengagement facility. This is of interest to me because it would allow a user quick release from belting should need be. Haven't found it yet. I'm also not hot about vendors requiring non TSO/not for certificated Acft. offerings.

[Paul Agaliotis]

Dale,
You're spot on with the non-TSO stuff. Seat belts are one of the few items that are required to be TSO'd on our little planes.
Paul

[MikeB]

I haven't looked at it too carefully but I had planned to use the Wag Aero "Y" type seat belt combination" shoulder and seat belts on my Chief once I get to that point. I notched the upper board on both sides before I put the headliner in and will wrap the belt around the spar carry through. Of course I need to cut a hole in the headliner also for the shoulder belt to come through. The belts are TSO'd and around $125 each side.
Mike

[bob turner]

You do not need TSO for shoulder harnesses on aircraft not originally so equipped. Many of the non- TSO shoulder harnesses are actually better and safer than the TSO type.

You do need an accepted standard - - FAA says SAE is ok -and a mechanic's signature. This is one of the few enlightened new FAA policies.

Lap straps need to be TSO - and Spruce has the good Rupert 3" belts.

[skyking3286]

I had better access to the rear spar thanks to a overhead window 337, but I used a modified hacksaw blade, a piece of aluminum to go over the rear spar and protect it from nicks and such and a metal sanding bar for RC planes.

[bob turner]

A lot of folks, and including one STC that uses 1/8" plate steel and AN-6 bolts, attach Cub shoulder harnesses in the center of a tube that spans the rear spar attach point. A crash in trees could bring that tube right in to the back of the front pilot's head as the wings collapse rearward.

My advice has always been to pay attention to which way the structure will collapse, and to never use hardware that is ten times stronger than the airframe it is attached to, at least for shoulder harnesses. The whole idea is to use the collapse of the airframe as a cushion to slow your body movement.

[MikeB]

In some cases (and the Chief is a good example) there aren't many options as to where to attach the shoulder harness. I had looked at the upper left and right cluster carry through cluster but attach options are pretty limited and having some 'give' on the shoulder harness attach point on the carry through seems like a good idea and a better idea than banging your head on the dash with no harness. Even a better idea is not to have a crash, I guess.

Mike

[Paul Agaliotis]

With more and more harness set-ups being installed, It would be good to look at AC 21-34 for installation of these systems. It covers the TSO C22 for the lap belts and TSO C114 that covers the harness restraints. It gives some great examples of installations.
Paul

[wwillyard]

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