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Berchmans 03-31-2017 11:28 AM

Second Seatbelt for Aerobatics
What have people done out there for installation of a second seatbelt for aerobatics that pass the IAC requirements of a separate attachment point?

sandifer 03-31-2017 11:42 AM

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.

WillyEyeBall 03-31-2017 01:39 PM

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)

jpowell13 03-31-2017 10:09 PM

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

Marabou 04-01-2017 02:23 AM

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 Vanís what they think about flap rod?

ronschreck 04-01-2017 06:51 AM

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.

jpowell13 04-01-2017 10:22 PM

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?

SuperCubDriver 04-01-2017 11:32 PM

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.

ronschreck 04-02-2017 05:32 AM


Originally Posted by jpowell13 (Post 1162570)
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?

Yes. That's the preferred location.

jpowell13 06-07-2018 08:26 PM

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.

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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