I?ll take a Stab at some of the original questions, mainly because I?ve had a chance to experiment with various chute types, helmet/headset types and fly an RV-8.
On the WHY? Simple. Stuff happens. So if you are an adventurous pilot who likes flying 3 feet from others, it could save you. If you are a really adventurous one who likes to do 20 minute acro sessions that require you to write down the sequence so you can remember it all, it?s also a good idea. One, confidence. Two, you can?t discount Geese, Buzzards, and morons in spam cans that seem to think your smoke trail is something they want to fly through.
On the chute type, Seat Cushion versus Back Pack question;
Seat Back Style: If your RV-8 is going to have the adjustable rudder pedals (honestly, you?d be smart to install them no matter what) you can get away with a Back Pack style chute. No matter what the manufacturer tells you, a Seat BACK style chute IS going to push you forward further than the standard seat back cushion from Vans. So you will feel a little cramped in that the instrument panel and windscreen bow will be closer to your than you are accustomed too. However, long term flight in the back pack chute is generally a non -issue. I have flown five or more, one hour hops with about a 30 to 45 minute rest between hops with no appreciable pain using this type of chute. In this case, it was a Para-Phenalia MINI. No pain. No discomfort. Nothing. Personally however, I did NOT like the back pack design in the RV-8 because I felt it really pushed me further forward than I like, but with adjustable pedals, it was not really a problem, leg wise. I am 5? 10 inches and needed to adjust the pedals forward a notch or so. Without adjustable pedals, forget it unless you are shall we say, vertically challenged. None-adjustable pedals may mean you may not be able to use a seat back type. Borrow one first to find out. In my case, the chute was used mostly for close formation flight, and it repositioned me so that the windscreen bow was dead in the middle of my line of sight to the lead aircraft I was formatting on, particularly from the number Two position. No so bad if off his right wing. So if you plan on doing that sort of thing, you need to consider seating position and site lines when deciding which way to go between seat pack or seat cushion types. Best advice. BORROW both and find out. On the upside, I think it would be very easy to get out of the RV-8 using this type of chute as there is nothing hanging down below you. When you ?rise? to clear the cockpit (roll, fall, whatever) the chute is rising with your back and clears the seat back as you egress. This IS important. If you gotta get out, a back pack design may be a lot easier to egress the RV than a seat cushion pack.
Seat Cushion Style: The seat cushion types (Strong Mod 304 etc.) is wonderful in as much as it does not screw with your site lines. You remove your seat bottom, and put a 1 inch thick by 6 inch wide by 14 inch long piece of hard foam in the seat pan (which is used to keep the chute pack level). When you climb in, you now have the same seat height as you would have had with the seat cushion in place. Your fore and aft sight lines remain the same as well, so there is no need to readjust your head position constantly due to the windscreen bow being in the way. The DOWN SIDE of the seat bottom type is that it?s like sitting on a briquette. Worse, in the RV, you cannot use a thick cushion on top of the chute because there is not enough head clearance. You can order padding from Strong, but height is critical in the RVs. So you have to test the concept before spending $$ on a seat pad you cannot ultimately use. If you do not level the chute with a filler pad beneath it , you might be able to get away with some sort of pad on top of the chute. The concern then becomes that the chute is angled too steeply at the front and cuts off leg circulation. I have about 20 hours sitting on these suckers for formation flights and even with the aforementioned 40 minute break between hops, you are in agony after about three or four hours. I also wonder if egress will be as simple with the seat bottom type. Probably not, but its one more thing hanging down inside as you bail. However, several war bird guys have used the Strong 304 and 306 models to actually save their keister?s when it hit the fan. I recommend reviewing the Big Beautiful Doll youtube video on just how quickly it can go bad and how low you can be and still survive with a Low Porosity canopy. When the pilot parted ways he had 500 to 600 feet left to impact. The canopy popped, he swung once, and was on the ground! They WORK! Finally, if you are not flying hard core hops like mentioned above, the seat bottom type is comfortable enough for a typical session of sky busting.
Personally, for ease of egress and comfort, I want to say stick to the seat BACK design in the RV-8. Naturally, being and idiot, I insisted on buying the seat bottom type due to the sight lines. I do more formation than acro of late and it annoyed me to no end being so forward in the cockpit.
On Helmets. Love them or hate them, IF you are going to use one, you SHOULD look into a quick disconnect plug: part number U-92A/U which is also part MS177/3-1. This allows you separate your helmet from the headset cables in a HURRY. You simply have to splice it inline a few inches down the line from the helmet proper. You then rewire the remaining long lead on the jack/radio side to a TP-120 plug, which plugs into the U-92A/U on the helmet side. Rather than having to reach down and find your headset jacks to pull the mic and speaker plugs, you just tug on the central plug (the TP-120) going into the U-92A/U adapter and off you go. Why bother? I have heard several stories of folks trying to bail only to be yanked back in by their lead wires. The Adapter gives you a break away point even if you forget. Of course, a headset is a different story. Those you can toss. But a helmet is not coming off should you need to leave the premise quickly.
As far is wearing a lid, I seldom do for anything but acro sequences or tight formation. But I can tell you if you are doing a lot of formation in clear whether, that visor is an EYEBALL saver, or maybe even a life saver. Using sunglasses and a visor, you can look straight up at the leader while the conniving, mean spirited, foul rat B****rd positions you so that you are staring right into the sun for 367,921 seconds or the end of time, whichever comes first! Without it, wow, PAIN. So people may want to laugh at you for wearing one, but you kept position and did not hit anyone else?s aircraft for being blinded!
Nice to have coming over the top of a loop into the sun as well.
Canopy release. Enough covered here. But there are plenty of methods to get the RV-8 lid to part ways. That?s the least of your worries.