Real life RF limits

[AK Dad]

I never imagined hitting a soft seat back regardless of the crash force causing any real serious damage

That's one of the things that becomes less obvious as G-forces increase. At a certain amount of force "soft" no longer does any good because, depending on the properties of the materials, it compresses too quickly and essentially acts as though it's not there. What you get then is nearly equivalent to direct contact with hard structures within the seat, like the metal frame for instance.

In the early days of ejection seats in fighter aircraft they were finding a lot of guys with real-world spinal injuries that were not predicted by testing. What they found thru investigation was that a lot of pilots were adding their own extra seat cushions because the ejection seat cushions were so uncomfortable. What the pilots didn't seem to realize was that the seat cushions were so thin and uncomfortable because you couldn't have too much cushion that allowed the seat to accelerate prior "hitting" the pilot in the rear-end.

Hope that didn't seem too far off topic, but that's part of the reason that having things like heavy coats or loose installs can lead to injuries in CRs.

 

[nataliem257]

That's one of the things that becomes less obvious as G-forces increase. At a certain amount of force "soft" no longer does any good because, depending on the properties of the materials, it compresses too quickly and essentially acts as though it's not there. What you get then is nearly equivalent to direct contact with hard structures within the seat, like the metal frame for instance.

In the early days of ejection seats in fighter aircraft they were finding a lot of guys with real-world spinal injuries that were not predicted by testing. What they found thru investigation was that a lot of pilots were adding their own extra seat cushions because the ejection seat cushions were so uncomfortable. What the pilots didn't seem to realize was that the seat cushions were so thin and uncomfortable because you couldn't have too much cushion that allowed the seat to accelerate prior "hitting" the pilot in the rear-end.

Hope that didn't seem too far off topic, but that's part of the reason that having things like heavy coats or loose installs can lead to injuries in CRs.

It didn't seem too far ;-) if hitting a seat back during rebound (which happens in every single frontal impact crash with a rear facing restraint) can result in a cracked skull, it certainly makes me wonder why more manufacturers don't allow for it. Which brings us back to the original question!

 

[Amyfromky]

Anyone else like seats that provide rebound control? Like Radians and Britax and Foonf and True Fit? That's one of my criteria, personally (just seems like since the data we have say RF to two is safe, should we be more like Sweden for kids bigger than that RF? Are the minor facial/skull injuries from rebound that we see in tiny RF babies likely to be worse in big preschoolers RF without rebound control? Just pondering...)

We just replaced our seats because of an accident and one of the things that attracted me to the Foonf is the rebound bar. I like it better than the tether of our Diono and Britax because I can push the captains chair back with it installed and get behind it so I can get to the 3rd row.

 

[joolsplus3]

I must have this burned into my brain after enough readings (wow, it needs updating! 'big' RF seats that go to 2? old news!) http://www.carseat.org/Technical/tech_update.htm#toptetherRF

I remember hearing 'minor orbital fractures' at some point, though a google search doesn't come up with much blaming RF crashes for that.

Here's what looks like a pretty impressive side impact video, but the rebound looks like it's more than it could be (Of note, Canada has the same seats but with big front bolsters at the sides/legs to prevent rebound, it would be cool to see the same seat in the same crash) [ame="http://www.youtube.com/watch?v=dTGWx7mwL1I"]Child Seat Crash Test | Safety 1st Air Protect | Rear Facing, Side Impact Test | 3 Yr - YouTube[/ame]