Crotch Strap, or not?

[BSwayze]

I'm at a point in the center section of my fuselage where I need to make a decision about seatbelts. I notice that Vans sells 4-point seatbelt and harness kits, or 5-point kits with a crotch strap. Now would be the time to install the brackets if I go with a crotch strap. So I'm wondering...

What are most builders using? I admit I haven't paid much attention to this matter until now. What are the advantages/disadvantages of each kind other than the cost? Is it a compromise in safety to go with a 4-point seatbelt?

Thanks for any comments, suggestions, or input

[RichB]

I think the main difference is the 5 (or now, 6) point harnesses prevent "submarining" in an impact. Eg, you can't slide down under the lap belt.

[kiwipete]

The 5 point is much better when it gets bumpy. Helps keep you in the seat better with less chance of hitting your head on the canopy.

Cheers

Peter

PS You can retro-fit these later but it's much easier when building the centre section.

[RV10Man]

My brother did a 4 point in his 9A. The problem I have, is the shoulder harnesses pull the lap belt up into your gut. For that reason, I'm putting the 5 point in my -10, front & rear seats.

Marshall Alexander
RV10 N781DM
fuse/panel/cabin top

[yakdriver]

I like the crotch strap as it keeps the lap belt down across your thighs where it is supposed to be and doesn't let the shoulder harness pull it up. Mandatory for any negative G acro. Don

[N733JJ]

I'm not convinced of the merits of the crotch strap preventing "submarining". I don't think this is a likely scenario. This is more likely in a car where you can get hit from behind.

However, I do agree with Marshall, the crotch strap does keep the lap belt low on the hips where it belongs. The lap belt should be installed so that it holds you down into the seat. The crotch strap helps this be preventing the shoulder straps from pulling the lap belt up. The shoulder straps should prevent forward movement (into the instrument panel), not to hold you (via the shoulders) into the seat when in turbulence or inverted! Without the crotch strap, we will find the shoulder straps will exert downward pressure on your shoulders in these situations. This can cause broken collar bones.

In the corporate jets I fly, one does not have a crotch strap and it drives me nuts. The lap belt is always riding up towards my stomach where it will do no good (maybe some harm?). Fortunatly, that airplane will soon be replaced and the new aircraft will have a five point system.

Go with the 5 point, it is more comfortable, safer and will give you the feeling of strapping in, becoming one with your machine, not just getting in it!

Scott A. Jordan
N733JJ

[vernh59]

In the UH 60 I fly there is a five point harness. In the C-12 (Army King Air) there is the standard 4 point. The 5 point harness is much more comfortable because the lap belt doesn't have to be as tight to stay in position. In the event of a negative G loading the lap belts posiion is maintained by the crotch strap not your hips. My -8 will have the five point harness.
On the subject of restraints, do any of you guys use an inertia real on your harness? Pros? Cons?

[Mel]

If you have the option of installing the crotch strap, do it.
The best thing it does is to keep the lap belt low where it belongs.

[Ron Lee]

Never Armour All critical surfaces.

I have a four point belt systems and would prefer five because of the turbulence we get in the Rockies.

Install the hardware needed for a five point.

[Steve Barnes]

One time I hit a bump that was 4.5 positive and 2.5 negative, the crotch strap made it a non event.