VAF Forums

VAF Forums (https://vansairforce.net/community/index.php)
-   RV-7/7A (https://vansairforce.net/community/forumdisplay.php?f=7)
-   -   Secondary Lap Belts (https://vansairforce.net/community/showthread.php?t=104138)

Daniel S. 09-10-2013 08:02 AM

Secondary Lap Belts
 
Hey guys.
I've wrapped up most all of my interior purchases / finishings etc... (yeah, yeah, yeah.. I havent started the fuse yet. :rolleyes:)... I've been planning this build for many years & know exactly what I want, so I spread out costs from time to time. The $5k+ on interior junk being one of those things. I'll blame costs on the wife as she required heated seats & other amenities not typically found in -7s. I just ordered the last pieces that I know of (seat belts). I got crow 5 point harnesses. BUT I've always had this fear of seat belts not being completely latched or letting go during inverted flight :eek:... Irrational as this fear may be, I want to build a little redundancy into my restraint system. My first aerobatic trainer had a secondary / two stage locking lap belts. Has anyone installed a secondary lap belt in a -7 with secondary anchor points? It would be nice if I could make them easily removable! Any ideas / plans / pics etc.?

schristo@mac.com 09-10-2013 08:27 AM

Planning to hang from the belts?
 
Unless you plan to fly purposfull negative gee maneuvers it is completely unnecessary...

Daniel S. 09-10-2013 08:34 AM

If you have the systems, why not pull a neg -G here & there? I know the -7 is not the best inverted, but nontheless its fun to tinker around inverted ;)... Yes, hanging from the belts.

Low Pass 09-10-2013 08:38 AM

Quote:

Originally Posted by schristo@mac.com (Post 806013)
Unless you plan to fly purposfull negative gee maneuvers it is completely unnecessary...

Agreed.

And conversely, if you plan *sustained* negative I believe you need a secondary (lap) restraint. Or a parachute.

bret 09-10-2013 08:41 AM

Some one else tried this rout, he ended up not doing it, and put everything back stock.

David Paule 09-10-2013 08:44 AM

Consider emergency egress on the ground, too, especially for a passenger that isn't familiar with the airplane.

Dave

Daniel S. 09-10-2013 08:52 AM

Yes, ***Sustained*** If a belt fails or isn't latched properly, I'd perfer stay with the plane rather than unintentionally bailing out with a parachute. Me being the safety freak that I am, I'll probably have both a chute & a secondary lap belt anyway. Im not really asking if it's needed, it's more of a how question :)

Thanks

schristo@mac.com 09-10-2013 09:00 AM

Have fun ;)
 
A touch of negative here and there is fine by me, and I don't mind cleaning up some oil on the belly but inverted push is really not much fun. Just make sure that you have everything in the cabin secured... a friend who used to fly unlimited busted an RV6 canopy from a phone coming loose out of a pocket when pushing around inverted!

Provision for inverted oil, or a half raven setup... extra cost and weight but everything is a trade off. For a long time I have been going back and forth on installing a half raven system and/or smoke... I have all the pieces for smoke now and am just dragging my feet but have not moved on inverted oil. If I were to do it again I might install the half raven and an accumulater... still on my list of maybe but there is not much room for mounting without major rework.


If you have the systems... Why not...
Mostly RVs are ready to fly at any time with flight bags, tools, Oxygen, and lots of misc stuff loaded up ready to go.. even then they are ready for some lite acro... if you want to get a bit more spirited you need to pull all of that out, perhaps grab a chute, remove the back cushion...

Daniel S. 09-10-2013 09:06 AM

Looking at the plans, I'm wondering if the few that have mentioned installing secondary belts didn't just use the same anchor point(s)? Those should / better be plenty stong.

larrynew 09-10-2013 09:10 AM

Daniel, here are some previous VAF discussions about secondary lap belts.

http://www.vansairforce.com/communit...ad.php?t=30395

http://www.vansairforce.com/communit...ad.php?t=20892

Low Pass 09-10-2013 09:18 AM

Quote:

Originally Posted by Daniel S. (Post 806031)
Looking at the plans, I'm wondering if the few that have mentioned installing secondary belts didn't just use the same anchor point(s)? Those should / better be plenty stong.

Well, how strong is plenty strong? Remember your design needs. The main attachment is used (worst case) *alone* for crash or off field landings. The secondary lap restraint is used in the *one* instance your main belt fails. In theory, the secondary point must be good for ~1.5G worth of load. I would think (way off the top of my head), you could drill a 3/16 hole down somewhere on the anchor assembly and install an AN-grade screw eye. Connect some 3/32" aircraft cable and route up to an attachment up above the floor board somewhere for the secondary restraint. Just one wild idea.

Daniel S. 09-10-2013 09:29 AM

Thanks Larry!
Those were exactly the posts I was looking for!!! I remembered them but couldn't find them. I guess I'm a search dummy!

Daniel S. 09-10-2013 12:52 PM

No Luck
 
I've gone through all of the old posts & have yet to find any *Sucessful* secondary anchor point mods. Maybe, I'm being naive to the floor design, but I dont see why you could add 4 secondary ribs with 1/8 inch stock doublers between them & bolt directly to the rib sandwich. I'd think that would be plenty strong to me snug at -2Gs (450lbs).

***Rib sandwich (my idea)= Stock rib & placement, then a 1/8inch doubler, then a secondary rib with opposite flange orientation... All this riveted together as one floor rib & riveted in place. AN4 bolt through the sandwich, trim flange where belt passes through floor, add second ratchet type lap belt The only draw back I can think of is added weight. Dumb mod idea?

SuperCubDriver 09-10-2013 01:28 PM

I also wanted to have a second lap belt for the occasional aerobatics. I am not afraid that the belt itself is failing - more that it is not perfectly closed or I open it inadvertendly during flight with the control stick or however.
So what I did is using the same anchor points and installed some aluminum spacers. I bought a lap belt from Aircraft-Spruce with two removable ends. These are easily installed when needed and the belt can also be used as baggage tie-downs with another anchor point at the rear of the baggage compartment.




All times are GMT -6. The time now is 07:58 AM.