Just_a_fan wrote: ↑
Tue Feb 13, 2018 11:33 pm
djos wrote: ↑
Tue Feb 13, 2018 11:13 pm
We know a lot about it actually, it's the same material used in the F16 cockpit which can handle bird strikes at 1,000 kph and not shatter. The FiA even fired a wheel at an F16 cockpit and it absorbed the energy and deflected the wheel without any issues at all.
The aero screen is not the same as a full canopy. The big hole cut in the top to let the driver get in totally changes the way the screen can handle applied loads. I'm struggling to see why people on a technical forum don't understand this.
"The F-22's canopy is approximately 140 inches long, 45 inches wide, 27 inches tall, and weighs approximately 360 pounds. It is a rotate/translate design, which means that it comes down, slides forward, and locks in place with pins. It is a much more complex piece of equipment than it would appear to be. The F-22 canopy's transparency (made by Sierracin) features the largest piece of monolithic polycarbonate material being formed today. It has no canopy bow and offers the pilot superior optics (Zone 1 quality) throughout (not just in the area near the HUD) and it offers the requisite stealth features. The canopy is resistant to chemical/biological and environmental agents, and has been successfully tested to withstand the impact of a four-pound bird at 350 knots. It also protects the pilot from lightning strikes. The 3/4" polycarbonate transparency is actually made of two 3/8" thick sheets that are heated and fusion bonded (the sheets actually meld to become a single-piece article) and then drape forged. The F-16's canopy, for comparison, is made up of laminated sheets. A laminated canopy generally offers better bird strike protection, and because of the lower altitude where the F-16 operates, this is an advantage. However, lamination also adds weight as well as reduced optics. There is no chance of a post-ejection canopy-seat-pilot collision as the canopy (with frame) weighs slightly more on one side than the other. When the canopy is jettisoned, the weight differential is enough to make it slice nearly ninety degrees to the right as it clears the aircraft."
The costs for a whole unit are 10X more then a halo, they are very very heavy and need additional air and safety measures (because of fumes), heat prevention and fragile for scratches etc. Plus, 4 pounds (around 2kg) at 350 knots is not a lot compared with the loads that the halo will be able to have.
Lets see what happens when Indy will crash test their solution.