Take the emotion out of it, please
Not completely true. I have crashed a composite that lands about 20KTS faster than an RV and sinks a **** of a lot faster. Walked away with trivial injury and the plane will fly again. Had I hit at the same velocity and sink rate in my F1 (a metal plane ) the engine would have deformed right into my lap leaving me quite dead.
There are many components on a composite that will absorb impact ie landing gear, engine and engine mount, cowling.
Your science about deformation is correct but the conclusion suggests that composite planes are death traps compared to metal aircraft. This just ain't so.
It depends on what you hit, how you hit it and as mentioned a combination of your vertical and horizontal velocities.
Survivability in a composite is every bit as survivable as in metal if not moreso.
I was a Boeing engineer on composite analysis years ago out of college. I'm appreciate your opinion, its just not based on facts. Composites don't deflect, yield or deform, they take ultimate load and fracture. You can make sacrificial composite structure to absorb energy but not primary structure like wings and fuselage.
WHO IN THE HECK SAID DEATH TRAP? 
I NEVER SAID THAT! However they (all composite) planes just are not as "friendly" in a crash, period, especially ones with higher stall speeds.
With out emotions, look at cold hard facts. Composite structure can be very strong, durable and safe............... however the STRESS-STRAIN diagram says it all. IT DOES NOT ABSORB ENERGY. One strategy is make it heck for stout, so it does NOT FAIL at all ever. Yes that's great but also very heavy. Most composite planes are as heavy or heavier than equiv metal planes or rag-n-tube planes because "when in doubt make it stout". Most composite planes are overbuilt for flight loads, which is a bonus in a crash. When a metal plane crashes it "balls up". When a composite plane crashes it cracks and burns to the ground. You don't ball up composites.
The energy absorbing characteristics of structural composite materials are suckie (engineering term). Metal bends, deforms and absorbs energy. The RV is not Gods gift to aviation crash worthiness. Far from it, it is fairly light structure and YES your feet are right on the firewall next to the engine, BUT THAT IS NOT THE TOPIC. Lets stay focused. These discussions always turn to "but oh yea well your xyz is this and that". RV's have nothing to do with Lancairs, except they are both planes.
For a bush plane that might crash into trees middle of no where, give me a steel truss airframe (aka, Cub, Maule), super strong, maintains integrity (yields not fractures) and absorbs energy.
Given a choice of making an off field engine-out landing in a Lancair IV-P -OR- RV (any), put me in the RV. Given a choice of any plane, a super Cub with stall kit, 5 pt harness and helmet.
I know talk of crashing is emotional, but we assume some risk when we fly regardless of the model plane we fly. This idea you can crash and die is not really news. I highly suggest not crashing.
You're changing the subject with your composite plane saved your life and think the F1 (Rocket) would have been fatal story. It is also vague. What kind of plane and accident was it? Sorry I don't know the details.
There are scenarios where a composite plane might not fail in a crash, maintains engine mount, wing tanks and cabin envelope remains intact. Where a metal plane in the same crash may deform too much and be worse. Sure they say wearing your seat belt in a car can kill you sometimes? Could happen.
If you make the composite plane very strong, which many are, it adds weight, lots of weight. You can't make a plane 100% crash proof survivable.
You're also right, a hit directly on the noise of an RV, pushes the engine up and back, more than likely rotating it into the cockpit area. With the compact design of RV's, your feet are right there. I have seen two accidents where the impact direction and force was great enough to cause this to happen, both fatal, most likely stall spins. The whole plane was intact but the engine came back into the cockpit. Lesson? Don't stall-spin or stuff your RV straight into the ground because it will hurt (not for long however). HOW TO FIX THAT? You could "fuse" the engine mount (make it weaker so it fails first) and beef up the aft firewall structure that takes engine loads.
The idea in an off field crash, you hope if you hit something, the landing gear, wings, tail, aft fuselage takes the blunt of it and the energy VECTOR is more horizontal than vertical.
Lets face it, we sit over a wing spar (not directly thank goodness), under a plastic bubble*, with thin metal sides and a couple of angles. Still that stuff does provide protection. You really hope the wings, tail, aft-fuselage and gear take most of the initial impact, to absorb the energy. An accident with a large vertical component (like a spin) is hard to survive in any airplane because the human body can take many many times more G-force in the Fwd/Aft direction than vertical. *(Except for the -10, which happens to have a composite roof. The RV-10 is probably safer because its bigger, more metal to absorb energy.)
The topic is not to BASH RV's to make composite airplane pilots feel better. Composite pilots should know the limitations of the kind of material their plane is made from. Why not accept that limit? Knowledge is power. People ascribe all kinds of great things to composites, some of it is true, but there are down sides.
What you find with Lancair or **Legend accidents, is they burn to the ground after an off field landing. The fuel tanks often lose integrity (meaning fail). I avoid flying planes with fuel tanks behind the instrument panel or under the seats. Many Glasairs have wet-center section tanks. No thanks. Keep the fuel out side the fuselage. RV's separate wing "fuel cells" are pretty good. May be a bladder would add more protection but also weight **(Turbine two seat tandem P-51'ish kit plane)
Everyone is so sensitive. Composite planes with higher than average landing or stall speeds are therefore have LESS crash survivability statistically and from an engineering standpoint. Their is no debate about that. There are many many ways to mitigate this, but typical composite kit planes don't have these safety features, one being 18G seats. I worked on aircraft airline seats, and they are made to move and bend with out failure to absorb energy without transfering that energy to the seat occupant. They cost a lot and there may be no room in a homebuilt plane for one. (Take a good look next time you are on an airliner.....look under those uncomfortable seats at the structure....a lot of work went into them to make them sturdy but "soft" enough to not transfer forces into the occupant.)
I don't have a grudge against composite materials and studied it in college and analysed it for a living, for a time. It is great stuff, but aluminum has a slight edge in an accident material wise. Design and how you use those materials is a different issue. I am talking material only.
Planes like the Sukhoi Su-29 Tandem two-seat aerobatic aircraft, has 60% composite. Why not 100%. Because they where smart and used steel truss fuselage (covered in graphite/honeycomb panels). Why? Its better, lighter and crash survivability is better than an all composite fuselage. The SU-29 has an ejection seat option! The wing limit is 18G ultimate (12G limit)!
