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Preferences on 4pt vs 5pt seat belt harnesses?

W

WJONES

Member
Hello all,

So what do you think, for us non aerobatic guys is the 5pt systems really
necessary? The 4pt seems like less hassel and cheaper too! Thoughts?

Wes Jones
RV-9A
Fuselage
 
The seatbelt geometry on the side by side airplanes isn't good. I believe there is a significant chance that, in the event of a crash, you would submarine out of the belts if you didn't have the crotch strap.

If you are not sure, find someone with a side by side RV, adjust the seat and cushions to fit you and strap in without using a crotch strap. Try to visualize what could happen to you in the event of a hard landing which compressed the seat cushions and caused your body to slide forward.
 
I was told by someone I had faith in (I believe a fellow from Hooker Harness, but Im not positive) that the crotch strap was not so much to protect against submarining, but to hold the lap belt in the proper position - i.e. low on the waist. Without the crotch strap, the lap belt tends to ride up higher on the abdomen, where it is more likely to harm some internal organs during a crash. For this reason, it is NOT considered just extra protection that is only needed by those doing aerobatics. Makes sense to me.

regards

erich weaver
 
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Kyle Boatright said:
The seatbelt geometry on the side by side airplanes isn't good. I believe there is a significant chance that, in the event of a crash, you would submarine out of the belts if you didn't have the crotch strap.
Click to expand...

This may be one of those situations where the cure is worse than the disease.

***OUCH*** :rolleyes:
 
jcoloccia said:
This may be one of those situations where the cure is worse than the disease.

***OUCH*** :rolleyes:
Click to expand...

Well, as someone else said, the crotch strap's primary job is to keep the lap belt positioned properly. Hopefully, the strap isn't directly stopping you from submarining.

Of course, if you don't have a crotch strap, and do submarine, the stick is gonna put a hurt on you anyway...
 
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5 Point please!

Having "tested" a 5 point system (not in an RV) I wouldn't be without one.

John Clark
RV8 N18U
KSBA
 
I had a 5-point system in my aerobatic motorglider when I did cartwheels across the ground starting with the left wingtip. I received one small scratch on my knee. the scratch was so minor that the paramedic didn't even put a bandaid on it. Glad I had the 5-point system!
 
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I went with the 5 point due to the keeping the lap belt where it belongs. Hopefully I will never need the harness, but if I do I want everything I can have in my favour.
 
9A builder. Just got my 5 point from Hooker a couple days ago. For all the same reasons mentioned earlier.
Besides, it is kinda cool.
 
4 pt, 5 pt, 6 pt.

I'm not sure what the FAR's might say, but I'm going with the exact same 6 point that I have in my track-day car(Miata) if I can. It replaced the 5 point, and while I've not crashed it, I have had a few off-track excursions, and the 6 point is much nicer than the 5 point, for all the reasons you can imagine. Experience form other people, the split bar versions are more comfortable than the V versions. My split is nice. My car harness is a FIA rated 2" shoulder, 3" lap cam-lock pull-down Schroth.

SCCA club rules are requiring 6 point harnesses for 2007 or 2008, I don't remember. I think it's 2007.

Bottom line: the tighter you can tie yourself to the mass, the better off you should be in an event that turns your 1500-lb finely crafted piece of functional sculpture into a energy absorbing device. :eek:

Rick 90432
 
Rick,

I also thought about pulling the belts out of my Miata, like yours a track car, but then I started looking at the attachments holes on the car vs. what is used in the plane and elected to go with hookers for the -9.

Besides, I still have two more years left on the belts in the car before they expire.
 
rjcthree said:
I'm not sure what the FAR's might say, but I'm going with the exact same 6 point that I have in my track-day car(Miata) if I can. It replaced the 5 point, and while I've not crashed it, I have had a few off-track excursions, and the 6 point is much nicer than the 5 point, for all the reasons you can imagine. Experience form other people, the split bar versions are more comfortable than the V versions. My split is nice. My car harness is a FIA rated 2" shoulder, 3" lap cam-lock pull-down Schroth.

SCCA club rules are requiring 6 point harnesses for 2007 or 2008, I don't remember. I think it's 2007.

Bottom line: the tighter you can tie yourself to the mass, the better off you should be in an event that turns your 1500-lb finely crafted piece of functional sculpture into a energy absorbing device. :eek:

Rick 90432
Click to expand...
I must be missing something here. Where is the 6th point?
1/Left shoulder, 2/Right shoulder, 3/Left waist, 4/Right waist, 5/Crotch, 6/?
I understand separating the "Y' harness, but that doesn't add a point of body contact.
 
Vehicle, not body

The six points refer to points of attachment to the vehicle. The crotch strap becomes two crotch straps, leaving a nice v shaped area free of straps for your ... crotch.
 
That makes sense, but if that is the case, most 4-point harnesses are actually 3-point. Adding the simple crotch strap would be a 4-point. So a 3-point system as in standard automobiles is the same as what is normally referred to as 4-point in aircraft in that the shoulder harness actually attaches to one point on the airframe.
 
You're right. To fully describe the setup, I quess we'd need a 2 part descriptor, indicating both the body part count and the attachment point count. A side by side RV would typically have either a 4/3 or a 5/4, while my 8 will be fitted with a 5/5. Having been involved with both the aviation and race car areas, I'd never really thought about the fact that the nomenclature was not fully consistent within each arena, much less across both!
 
6 Point

Mel,

A few years back (I can't exactly remember when) the SCCA mandated 6 point harnesses. As mentioned above, the crotch strap requires two points, making an inverted V. Each shoulder harness requires a separate attachment but can be wrapped around part of the roll structure, as I have done in my Miata. (Horizontal bar behind the seats, not the roll bar.) Then the lap belt goes to points on either side of the seat. Also, they cannot be attached to the seat as you see in a number of production cars today.

Two other items are that they have to be 3" wide and they have an expiration date on the label. Just like old milk, they have to be tossed out and replaced when they expire.

Funny story: Since my car is still "street legal" and has a plate on it, Nora and I occasionally take it for a drive up in the mountains (after putting street tires on it). There is nothing so fun as driving mountain roads with a car capable of pulling over 1G in a turn! :D We were taking a leisurely drive when in a moment of inattention I entered a 10 MPH right hand mountain turn (meaning a cliff on one side and a granite wall on the other) at over 60. As soon as the back end started to rotate, I put the clutch in and locked up the brakes. We slid up that road sideways, across both lanes, between two blind turns. Not waiting around to see if someone was coming from either direction, I dropped the clutch spun it around at proceeded on up the road.

The only thing Nora said was, "I would like you to put a harness in on my side." I don't think she even raised her voice.

WHAT A WOMAN!
 
I have been wondering about 2" lapbelts compared to 3" lapbelts.

Is anybody you know using a 3" lap belt in a side by side? Right now I have the 2" belts with the crotch strap and the civilian buckle.

A couple things-- There's hardly enough room for the 2" laps IMHO.

also-- I can't imagine drilling two holes or mounts for a "six point" crotch because straight up between the ribs works perfectly.

also-- I am thinking of reverting to Military/SCCA old time belts because it seems simpler to put on, get out of and explain to passengers. (actually not changing what I have, just for another project.)

7a first flight 2/7/06
262 hrs.
 
5th point

Rember the one downside of the 5th point is you have to cut a slot in the seat cushion...Which I forgot to do of course. No matter, the guy that made the covers needs to adjust the seams on them ayway so one day I can use the 5th point.

Frank
 
Bill, you're killing me. I've got 18" of snow on the ground, the Miata is in the back garage sleeping, and you're talking about pulling lateral g's. Grrr. Where is spring?!

Rick 90432
 
Photo of 5th point installation

For these who installed the 5th point, would you please post a photo of the installation if you have one.


Paul
RV-7A Finishing
 
WJONES said:
So what do you think, for us non aerobatic guys is the 5pt systems really
necessary? The 4pt seems like less hassel and cheaper too! Thoughts?
Click to expand...
I too wouldn't be without a 5-point, and for three important reaons...
1) Anti-submarining in a crash as mentioned by others.
2) The ability to snug it down in turbulence. This is actually a big deal in an RV which rides a bit "harsher" than a Cessna.
3) More comfortable: with the lap belts snugged down it simply feels more secure and even comfortable.

YMMV,
 
5 POINT SEAT BELTS

I PERSONALLY WITNESSED A FATAL RV-6 CRASH AND I WOULDN'T FLY AN RV WITHOUT A CROTCH STRAP. THE CROTCH STRAP HOLDS THE LAP BELT DOWN WHEN YOU GET UPSIDE DOWN. WITHOUT IT, YOUR BUTT LEAVES THE SEAT BY ABOUT ONE FOOT. BINGO, A BROKEN NECK!
ALSO LEAVE YOUR SHOULDER STRAPS LOOSE ENOUGH TO ALLOW YOU TO MOVE OR LAY OVER TO ONE SIDE INSTEAD OF BEING HELD BOLT UPRIGHT. IF YOUR HEAD CAN'T MOVE EXCEPT FOR PRESSING AGAINST YOUR CHEST, IT WILL CUT YOUR AIR OFF.
I RACED STOCK CARS FOR YEARS AND HAVE SEEN IT ALL!
 
Another vote for the 5th ELEMENT

I am with cowboy, the crotch strap is key. You will submarine and yes you will have more internal injuries, depending or the direction of impact. You get use to taking one lap belt, threading the shoulders and crotch on it and than the other 1/2 of the lap belt, click. DONE. It's a minor inconvenience and you can still loosen the shoulders or lap in cruise as desired for more comfort.
 
I'm not gonna discourage anybody from putting in a crotch strap if they feel it makes them safer in a crash. I won't disagree there.

But jeez, after reading this thread and others and previous discussions on rv-list and what not, it sure sounds like a LOT of people don't have a friggin clue how to tighten their 4-point systems properly.

I often have to show passengers how to do it right. For whatever reason it's not intuitive to some people.

Leave your shoulder harnesses LOOSE. Tighten the lap belt DOWN onto your lap. Then snug up the shoulder harnesses.

As the seat cushions warm up and you settle in, LOOSEN the shoulder harnesses, tighten the lap belt, and then re-snug up the shoulder harnesses.

If you get into turbulence...same deal. Give the shoulders some slack, get that lap belt good and tight DOWN on your lap, then snug the others up.
 
Dan,
Now you tell me!
I was one of the people that didn't know
how to tighten safety belts, (until last Thursday).
While being bounced around wondering if I should
slow down to the blue line on the ASI, I slowly
learned to tighten the lap belt first and THEN the
shoulder belts.

Much better after that,
Tom
 
Thread Killer

Can anyone share an example of a death or injury related to a four point system in an RV vs the five point as a probable cause or even contributing factor? (same question stopped the rivet vs welded aileron push rod thread as, evidently, nobody could find one there.)
I too will not argue if someone feels one way or another is safer but it would be nice to see some kind of supporting fact if there are any. THanks.
 
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