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Second Seatbelt for Aerobatics

Berchmans

Well Known Member
What have people done out there for installation of a second seatbelt for aerobatics that pass the IAC requirements of a separate attachment point?
 
Not required for flying in Primary or Sportsman, which is most likely where you'd be with the RV. IAC rule below.

2.3(k) Dual seat belts with separate attach points and a shoulder harness are mandatory for Advanced and Unlimited (power and glider) categories. The same equipment is strongly recommended for Primary, Sportsman, and Intermediate power categories, but is not mandatory except when IAC Technical Monitors deem them necessary for the sequence being flown in these categories.
 
Ron has one

Ron Schreck has dual lap belts in his (I think) and can describe and take pictures. I have dual in my RV4 and attached with screws under the seat and floor. As Eric said, unless you like self induced punishment, not necessary, but I like to feel pinned in the seat.
Bill Mclean (willyeyeball)
 
Novice Idea

I've been thinking about this for my 6A. It may be a dumb idea, and I won't be offended if experienced aerobats say so, but what would be wrong with taking an automobile lap belt and attaching it to my manual flap control rod behind the pilot's seat (one end on each side of the seat) with climber's carabiners for a backup lap belt? Wouldn't this arrangement be strong enough to hold the pilot in his seat in case the harness was accidentally unlatched during or before inverted maneuvers?

Alternately, the carabiners could be hooked into eyebolts installed in my baggage area floor. My thinking is that the extra lap belt is not for crashes but to hold the pilot in his seat if the harness comes undone during negative g's and, as such, the attach points do not need to be as strong as with the harness. (My weight at the -3g limit would be about 600lb.) Also, I would like to remove the second belt for non-aerobatic flights. John
 
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I use flap control rod in my 7a. No carabiners just thick rope just in case if main harness fails. Of course this "scientific" method has nothing to do with IAS requirements but I hope it should work. I did not test it because it is easy to bend flap rod but it should work as a lifesaving future once then you have to replace it. Like airbag. Is it appropriate to ask Van?s what they think about flap rod?
 
The second belt is not so much a back-up in the event of a primary belt failure, but is usually a ratcheting belt that can be tightened enough to restrict pilot movement especially during inverted flight. I have found that I can better concentrate on flying aerobatic figures when I am firmly attached to the airplane and not bothered with the effort to keep my head off the canopy.

I secure my ratcheting belt to aircraft structure with pip pins for easy removal when not required.
 
I see what you mean Ron. Does the second belt go down a little lower toward the legs than the primary belt to prevent you from lifting out of the seat better?
John
 
I was more concerned of opening/unlocking the main belt inadvertendly so I installed like a receptacle for a second lap belt. The belt is installed in only 10 seconds and removed as quickly. When not used as a lap belt it serves as a baggage holddown. The belt is from Aircraft-Spruce like 13-00301.
I used the same attachment point and used AN-3 bolts (loaded in single shear).
The other AN3 bolt is clamping an aluminum tube between the arms so that the belt hardware slides in easily.



 
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What I did.

I had a couple of those cargo tie down rings that Vans sells plus some 2"x3"x1/4" angle and nut plates left over from my build. I cut the angle pieces to fit and bolted them to ribs under the seat pan. The cargo ring plates are screwed into nut plates attached to the angle.

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The second lap belt is the removable type belt sold by Aircraft Spruce. It goes across my legs and tightens up nicely without distorting the seat pan. Haven't had a chance to do any loops and rolls yet, but will try the setup and report back. The installation was fairly easy. The cargo rings are removable and strong. John

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Tried new lap belt.

I tried out my second lap belt setup today. With broken layers above and below I didn't loop, but rolled a couple of times, and the second belt across my legs did add to my stability. I think the installation is plenty strong for my 183 lb weight. It might not be strong enough for heavier pilots and/or negative G maneuvers. The belt cinches up tight, and there was no deformation of the seat pan. John
 
Second Seat Belt

Thanks for the replies. I have installed a ratchet on my Crow 5 point but just can get it tight enough to really hold my butt tight to the seat while inverted. Lower across the legs looks worth at try. Let me know how it works out.
 
Ratcheting Belts

I'm certainly no expert but I have installed two sets of Hooker harnesses in two airplanes and flown quite a bit of hard aerobatics in both.

A ratcheting belt is one of the best investments you'll ever make if you plan to do any negative g maneuvering. If all you plan to do is float over the top then don't worry about it. But, if you want to hold those 45 degree downlines, fly a decent slow roll, or do any outside figures, you MUST have a ratcheting belt. You simply CANNOT pull hard enough on a standard lap belt to secure your butt in the seat for aggressive negative g maneuvering.

You DO NOT want a ratcheting belt that comes straight off the fuselage bottom and runs across your thighs. You'll probably give yourself a blood clot or worse if you try that approach!

The ratcheting belt needs to cinch down across your hips. Otherwise, when you push any significant negative g, your butt will try and float up and out along the plane of the seat back. Not good. The belt needs to hold you both down and back into both the back and the bottom of the seat.

I use the same attach point for both belts. The risk I accept is a potential failure of the attach point. Any other failure, of the seatbelt or the latching system, does not depend on having independent attach points for the two belts. I think that's an entirely acceptable risk.

My advice - buy a Crow or a Hooker and double up on the same, plans built attach point. You'll be happy with that and completely safe within the limits of RV approved aerobatics.
 
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