Seat Belt Fittings

[Murray Randall]

Just finished all the seat belt fittings using an old discard Piper wing spar web.  I've always thought that the they were 6061 but have no basis for that assumption.  My napkin calc says the min capacity of anything in my filltings is 3000 lb.  I milled the slots with my Enco milling machine and sew the belts with my Singer commercial maching.  The buckle is labeled Mfg for Ford Motor Co, is all steel.  The weight of all the fillings is 2.83 OZ, add the budkle and it all comes to 6.25 OZ.  The Ford buckle is 3.41 OZ and the Beech Aircraft buckle also in the pic weighs 7.15 OZ. 

[Tom H]

I've never seen seat belt fittings made from aluminum.  Sure would save weight, but wonder if they are strong enough?  I think the impact forces are the critical design issue, and could be more than 3000 lbs?
I made the seat belts for LEU Treehugger from 4130 and re-purposed webbing from car belts.  Did not have a mill - had to drill a line of holes and hand file to make slots.  Good, honest work, all the time wishing I had a mill.

Tom H

[Sam Buchanan]

The 4-point harness used in RV-6-7-9 aircraft and available from Vans Aircraft (Part Number = SBH-TT6 BLACK, $95.00) works like a charm in the Eagles:

http://www.vansaircraft.com/cgi-bin/store.cgi?ident=1395409140-194-66&browse=airframe&product=seat-belts

Unlike many belts, these adjust on both sides of the lap buckle so you can center the buckle regardless of how the belts are installed. The shoulder harness also disconnects from the lap belt when it is unlatched which makes the harness very easy to put on. After trying a harness from Great Plains that didn't have this feature, I now fly a RV-6 set and it works flawlessly.

No fabrication required and easy to install.

[Murray Randall]

The 3000 lbs is a conservative treatment but the lap belt divides the load.  A 200 lb pilot at 10G gives something like 2000 lbs, 1000 LB at each side. The toung going into the buckle will wear against the hard steel retainer in the buckle and should be watched.  Yes the milling machine is wonderful.  I bought mine on Craig List for $750 and use it extensively.  The motor runs either 110 V or 220 V.  No 3 phase Bridgeport.  You must do slow work feeds as it is not as rigid as a Bridgeport, somethimes I see .002 inch per second.   What does the 4 point Vans harness weight Sam?     Mine will be a four part with adjustment at all four legs. The shoulder attachment to the belt is connected to the lap clasp at the clasp and can be loose with the lap attached if desired.   But wieght motivated me and the out of pocket cost was zero.  

[Sam Buchanan]

   What does the 4 point Vans harness weight Sam?     Mine will be a four part with adjustment at all four legs. The shoulder attachment to the belt is connected to the lap clasp at the clasp and can be loose with the lap attached if desired.   But wieght motivated me and the out of pocket cost was zero.  

Haven't weighed it but it is light, similar to a passenger car seat belt. The 5-pt racing harness I now have in the RV-6 is much heavier.

I know you want to build your own set, but I posted this info for other builders who will be looking for a nice harness that works well, is lightweight, and readily available at a reasonable cost.

[Murray Randall]

Yes that Van's seat belt is one serioulsy good bargain!!!   And your web site and contributions here have always been spot on, helping me and many many others, thanks again Sam.       (I am curious about the weight of the Van's belt and will see if I can get it from the Van's site)

[Jlwright]

I wonder if the general public can buy from Vans. I thought you had to have a builders number. Now that I've sold my RV I don't know of I can still buy stuff. Maybe that only applies to sub kits and engines for planes and not accessories.

[Murray Randall]

I don't see that Van's gives a weight for the $95 seat belt kit. It sure looks first class, easier to adjust belt lengths. Absolutely no doubt you would be getting excellent quality at a super good price.  But it sure looks seriously heavy!          (Yeah I harp about weight when I get up to the pulpit here on the site but I give the weight back with my four longeron fuse, door, windows, and sky light.)

[Sam Buchanan]

I wonder if the general public can buy from Vans. I thought you had to have a builders number. Now that I've sold my RV I don't know of I can still buy stuff. Maybe that only applies to sub kits and engines for planes and not accessories.

Jim, Vans will sell to anyone, they are one of the largest suppliers to the kit-built industry. Lots of people are using Vans landing gears, tailwheels, engine mounts, wheel pants, etc, etc.......

Place an order and they will be more than happy to take your money.  

[Sam Buchanan]

I don't see that Van's gives a weight for the $95 seat belt kit. It sure looks first class, easier to adjust belt lengths. Absolutely no doubt you would be getting excellent quality at a super good price.  But it sure looks seriously heavy!          (Yeah I harp about weight when I get up to the pulpit here on the site but I give the weight back with my four longeron fuse, door, windows, and sky light.)

I doubt anyone could make a good harness any lighter than the one Vans sells unless your using a ratcheting strap to tie yourself to the seat. The latch on the G-Force racing harness I now use in the RV-6 is as heavy as the entire Vans harness now in the Eagle.

Vans Aircraft was the inventor of "lightness fanaticism".  

[Jlwright]

Ratchet strap! There you go Sam, I'm on it. You did say you were switching to those right? :-)
Good to know I can still buy from Vans. Not sure where I got that idea. They have some small parts I would like to use on the XL.

[Bob S.]

THIS is the belts I used on my Legal Eagle..
Seemed light and uncomplicated. Included all fittings....

http://www.aircraftspruce.com/catalog/appages/seatbelt5.php?clickkey=7864

[grdev]

Do you have a photo of how you installed your harness?

[Bob S.]

I dunno WHAT happened to all my pictures I had in the Yahoo Group...I THOUGHT I had some picture there... Guess I will have to take some new ones... Basically I made some blocks from some nylon I got off eBay and clamped the seat belts @station 3 cross tube and the shoulder straps to the angle tube ... Too high according to Sam, but it fits well for me... if I have to really USE the shoulder straps to stop me from going through the dash, it will prolly bend that tube! But that will also soften the stop. If i ever re-do I will take it to the top longeron X point...almost straight back from my shoulders....

[Murray Randall]

For better or worse here's a pic of my home brewed seat belts mocked in, with only one shoulder strap for now