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Thoughts on installing crotch strap

Steve Ashby

Steve Ashby

Well Known Member
Sponsor
I need the opinions of those who are flying. I am working on the center section and I wonder wether I should install the anchor for the crotch strap. When I finish, I will not do anything more than "gentleman's aerobatics" (the occasional roll or loop) so is the 5th seat belt really necessary. Thanks for your input.
 
"Optional" Options

For my 2 cents worth; As I build, I think of the things that I want and will use but also what does the addition or deletion of equipment, etc do for the resale ability and value. Sure, I'd like to think I'll keep it forever, but I'm realistic. Is that crotch strap fitting (or __________ ) something that would excite or hinder a future buyer. Also, how easy / difficult is it to add or remove later.

I've added some crazy stuff to my plane as I'm building, but it's all easily removable.
 
I would like to hear how people are installing these as well. I plan on putting one in, but not for airwork.

The main thing a crotch strap does is prevents you from slipping down underneath the panel in an emergency landing when a severe head on impact has occured.

Of course, I don't ever plan on having one, but that is what it is for.

:rolleyes: CJ
 
Crotch Strap

I read a post some time ago when an RV (6?) had to perform a forced landing and it tipped over and the pilot ended up in the baggage compartment when it all came to rest. He never knew how he got there and said he had his "4 pt." belt on good. That convinced me to install a "5 pt." and I just received the crotch strap kit from Van's after scratching my head for a while and wondering how to best attach it. Their system looks pretty straight forward and should work well.

Doug
90116, 13B rotary, FWF
 
I heard the shoulder straps can come off your shoulders and you slip up and out of the seat belt. This can happen even if you lap belt is tight ... if the seat back moves during a crash. I would like to see a strap at chest high to connect the two shoulder straps together.
 
As I understand it, the crotch strap/5th pt is for withstanding crashes. Prevents "submarining" which apparently is a significant issue. I seem to have read something Van wrote about it that really sealed the issue for me. Does little good for RV-grade acro though.

If you're building the -8(A), putting the 5th point in isn't that big of a deal.
 
I put crotch strap anchors in my 6A (design of my own, done before Van's had a kit). Having flown in other 6's and 7's with only 4 point, I wouldn't consider not having the fifth point. The crash implications are obvious, but the normal straight and level flight advantages are clear once you have flown with both types in turbulence. The best way to be comfortable in turbulence is to be strapped in tightly, and that simply is not possible with the 4 point. The angle of the lap belts in the side by side types simply will not allow it.
 
Crotch Strap

I added the crotch straps after 2 years of flying. I am 6'3" tall and in rough air they hold you down a little better and keep you from cracking your head on the canopy. I simply like the way they hold the lap belt in your lap. I would say put in the hardware, even if you don't plan on using them. It is completely out of the way, when no belt is attached.
 
I agree with all that the crotch strap is a must in the RV. I havn't ordered mine yet, and am wondering how it attaches to the frame, do suggestions or instructions come with the belt?"
Larry
 
Low Pass said:
As I understand it, the crotch strap/5th pt is for withstanding crashes. Prevents "submarining" which apparently is a significant issue.
Click to expand...

Yes indeed. Back in '87 a DC-9-10 crashed on takeoff from Denver; lost control with ice on the wings, 28 fatal, including the cockpit crew. Rumor has it that the copilot wasn't wearing the crotch strap, just the lap belt/shoulder harnesses; his body was found wedged down by the rudder pedals after submarining under the lap belts. I'm not sure that the 5th strap would've saved him, but ya never know...
 
Crotch Strap/ Upside down venture

From my previous posts:
I installed Hookers in my 6A. I bought the 7 crotchstrap kit but did not use it. I used 5/8 inch high strength bolts and two large steel washers per rib. I pre-drilled the washers (used as strengthening doublers) so I could pop rivet them on either side of the ribs similar to the fuel drain fittings on your wing tanks.

Remember, all this work is done via 90 degree drill and between some narrow rib spacing.
__________________
Frank Eldridge (deceased) had this happen to him and wrote and spoke about his being thrown into the baggage area of his 6A. He was upside down with the plane partially in a wet area. He pulled his 5-6" pocket knife out and chipped out a large enough area on the rear baggage area to crawl out of the plane. Later I crawled back in that hole to recover some personal items for him. His only injury in the accident was a cut on his head from being cut by the plexiglass.

His best advice, some of which you will read in the links I added in the tribute I wrote a few weeks ago under the forum 'RV Friends Who Have Passed On' suggested:
1) Buy and wear the best seat belt/shoulder harnesses you can afford
2) Always carry a sharp knife on your person to use to break the canopy out.

I was on-scene within moments of Frank's accident. I helped recover the airplane and helped in the NTSB investigation. Frank's RV was kept in my hanger. I am very familiar with this accident and the excellent protection the RV-6A design provided.

So, with this experience as a background, I have a canopy breaker tool from an F-4 mounted on the back side of my 6A flap motor mount. I have a strong folding hunting knife in a side pocket. I installed Hooker harnesses along with a strong crotch strap. I used removeable 'gear' pins to hold my slider canopy on the front canopy mounts.

From one of Frank's articles:
--> RV-List message posted by: "Frank Eldridge"

January 1, 2003, I had a forced landing in a RV6A. After a ground roll of about
20 feet in a swampy area the plane ended up on its back. I found myself in
the baggage compartment unhurt. I had always thought that I could kick plexiglass
in the canopy out, but I could not. I always carry a pocket knife with a three
inch locking blade and I was able to take that knife and break a hole in
the canopy to get out. The only blood in the airplane was where I cut my hands
on the plexiglass breaking a larger hole in order to extract myself. I strongly
recommend to all my RV friends that they carry a knife like mine in their
pocket because in my case I could not have got to a tool in the cockpit of the
airplane. I have followed RV accidents very closely since mine, and a large
number wind up on their back. So, please get a knife and keep it in your pocket
when flying an RV. There is a story about my accident posted on Doug Reeves
Van's Air Force Web page. Here is the link to my particular article:

http://www.vansairforce.net/articles/FrankEldridge0.pdf
 
5th point

I installed the starps but after my freind upholstered the seats we found that you have to cut a hole in the seat cushion to make it work. This is OK as long as you never have to ajudt the seat back position...At least I guess, because I have not brought myself to start cutting holes in my expensive seat cushions yet.

frank
7a
 
Get them

Having flown extensively in an RV-6A without them and an RV-6 with them I decided to put them in even if I have to devise my own mods to Van's kit. I agree with N819VK and Alex.

To quote N819VK: "in rough air they hold you down a little better and keep you from cracking your head on the canopy. I simply like the way they hold the lap belt in your lap."

Yep

And to quote Alex: "Having flown in other 6's and 7's with only 4 point, I wouldn't consider not having the fifth point. The crash implications are obvious, but the normal straight and level flight advantages are clear once you have flown with both types in turbulence. The best way to be comfortable in turbulence is to be strapped in tightly, and that simply is not possible with the 4 point. The angle of the lap belts in the side by side types simply will not allow it."

Yep. The belts seemed to want to go across my stomach instead of my beltline.

lrfrey, the mounts go between the floor ribs. I have pictures but don't have access to them right now.

FrankH: Are your seat cushions in the way of the strap coming up from behind the control stick being tightened enough? I am not understanding your issue exactly.

Most people put the adjustable seat parts in but I have never seen anyone actually use this feature.
 
Last edited:
arffguy said:
FrankH: Are your seat cushions in the way of the strap coming up from behind the control stick being tightened enough? I am not understanding your issue exactly.
Click to expand...

Using the Oregon Aero seat cushion with the seat back in the middle posititon. The crotch strap installed as per plans. The cushion is then in the way for the crotch to come striaght up...I.e the strap has to go forward to the notch in the set cushion...UP..And then back towards you lap belt.

Clearly this won't work so requires either a much deeper notch in the seat cushion...or a slot cut in the seat cushion for the crotch strap to pass thru...About 2 or 3 inches behing the notch in the seat cushion.

Frank
 
Hooker harnesses

I don't have my -8 fuse yet, but if anyone has some words of wisdom or pictures on fitting 5-point hooker harnesses (which I do have) then I'd be grateful.
Cheers,
 
Drop it in that there -8

Thanks Bryan. Was that part of the standard fuse kit? Or did you need to buy anything extra from Vans?
 
I had the std kit and installed my harnesses after a couple of years of using Van's std belts. The Hooker harness I bought had steel bushings in the aluminum ends that I removed. This was so the aluminum strap end fittings would ends would slide between the intermediate pieces that attach to the airfraft structure. Building new you could bend/fab your intermediate straps to accomodate the steel bushings if you choose.

IMO the bushings are there to accomodate a belt fitting that will swivel/move. Mine were sandwiched firmly and don't move. So I didn't see a significant need for the bushing.

Also, as long as we're talking harnesses. You might take a look at some of the auto racing suppliers. Summit sells lots of stuff that would work in an experimental. Check Simpson Racing too.

Hope that helps!
 
Got a hooker!

There was a group buy on some hookers ( :eek: ) so I took advantage of that and had a pair made up. They're really nice harnesses, so I hope they are as comfortable and safe as they look. Everyone raves about them, so I'm looking forward to installing them. Hmm, I guess I'd better actually order the fuse kit first!!
Cheers,
 
Install it Steve.
You will need it. I will need it:) There is no good reason to leave it out.
Best,
 
worthless_without_pics.gif
CJ
 
Okay, that is what I am looking for!

Rick, do I understand you correctly? That is a Vans setup?

I didn't knwo they had a kit for the crotch strap!

Hmmmm, that makes it a whole lot simpler!

:rolleyes: CJ
 
Yes and yes. The 7 kit will work on a 6 but it does require some modification to the parts (the rib spacing was 1/4 inch more on the 6, at least on mine.) I did it as a retrofit, and while it was more challenging than installing it during construction would have been, it was doable. If you can build an RV than you can do this.
 
5th strap

If you fly inverted or do any neg. "G" the crotch strap makes a big difference and keeps you cinched down against the seat much better than lap belt alone. The antisubmarine feature is a plus for my 2 cents.
 
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