Dual Lap Belt for Aerobatics

I finally got around to installing the 7-point Hooker harness in my RV. The hard part is devising a second attach point for the lap belt. I suppose some will attach both belts to the stock attach points but that does not give the optimum geometry for the belts and does not provide redundancy for safety. I needed to provide a second set of attach points further forward for the ratcheting belt so that the belt will securely hold my upper thighs from raising off the seat during negative G flight.

I used a 3/4 inch square steel tube that is welded to two tabs that secure the tube to the two floor longerons with four AN-3 bolts. The bolts go through the longeron angles and into nut plates secured to a 1/16 inch thick steel doubler. I welded some little tabs onto the end of the 3/4 inch square tube to attach the ratcheting lap belt. The seat cushion is quite thick over the tube but I cut a bit of foam out to let the cushion rest on the tube.

Prior to installation:


Belt attachment detail:
Lap Belt 3 by Ron Schreck, on Flickr

Installed:


That ought to hold me!

Nice one!

I might copy your idea.
Having thought about it in similar and different ways.
Looking good!

That's awesome Ron! I will likely plagiarize your idea! Thank you for sharing.

Nice!

I'm very familiar with your type , just can't sit longer than 15 minutes without turning things upside down . Thanks for sharing Ron. You just reminded me of Mark and every time he got in my -7 he screamed at me...." Bioni, (that's what he called me), where the heck is your crotch strap? I can't get in this plane without a proper 5 point harness" , he use to say... To that I would alway reply, "you could if you didn't have ants in your pants and could fly straight and level for a 30 minute flight ".

The mod looks great Ron. I may have to do that myself in Mark's honor

I remember the funny things Mark used to say to me too. He never called me by my first name. It was always "Esquenazi" and sometimes "Mr. Esquenazi". I always knew what he was going to say about the performance of my maneuvers by the inflection of the individual syllables of my name!

Mark is sorely missed by many. I know many of you didn't get to meet Mark. He was a long time IAC competitor and a friend of the RV community. He passed this summer quite suddenly and unexpectedly. More to follow on a separate thread.

Former Pitts/Hooker type.

What will the square tube and supports do in a ground impact?

At say 9g vertical, I would not want it either not yielding/deforming and creating injuries or becoming a steel bear trap and grabbing me.

I think it eyeballs ok, fwiw.

moosepileit said:

Former Pitts/Hooker type.

What will the square tube and supports do in a ground impact?

At say 9g vertical, I would not want it either not yielding/deforming and creating injuries or becoming a steel bear trap and grabbing me.

I think it eyeballs ok, fwiw.

Click to expand...

I'm not going to test that particular failure mode. The steel bar is about six inches below your butt with a standard seat cushion installed. The non-ratcheting belt is attached to the standard attach points and will act just like the standard belt in a mishap.

I suppose the ratcheting belt would come in handy if you crash upside down!

Here's some free advice from a parachute rigger/skydiving instructor/a&p mechanic and pilot.

For those of you wearing parachutes and considering your emergency egress procedures....cockpit snag potential is a very real concern. There are often many items between you and that open parachute that can either snag you on the way out, or catch a ripcord and cause a premature deployment. Either of which would ruin you day. Items such as; canopy latches, throttle and mixture controls, ratcheting seat belts, unsecured leg straps, etc. All of these are snag potentials and need to be considered. I would suggest talking to your local parachute rigger about this and develop a plan while still on the ground.

Blue skies and soft landings.