a data point
I'll relay a few data points from the guy I fly with all the time, 2 hangar doors down, who has a beautiful RV-4. He has a couple of "complaints" about its configuration...
1) He says he won't fly with a passenger over 200 pounds. The lack of pitch feedback when slow in that configuration can mess with you. Got any 201-pound friends you'd like to fly with?
His particular RV-4 has a hopped up O-360 with a heavy Hartzell up front, and even with that heavy nose he talks about the CG issue when a body is in the back seat.
2) Just 2 days ago he was saying he wants to add a moving map. He has no room to do it without panel surgery. I asked if he'd consider a handheld, ipaq, whatever, and his response was that anywhere he puts it, it'll be covering something else up. Not much space.
3) When we travel, range is somewhat limited by the -4's small fuel tanks. When flying with a pack of -4's, -6's, -7's, and -8's, it's the RV-4 that gets low on fuel first.
4) We do "photo missions" from time to time. When this guy's wife flies with us, we actually put her in the back of another guy's RV-8 instead of the RV-4. Gives her much more room with the camera & lens. In the -4 she says she'd be hitting the canopy and not having as much room to twist around.
He loves his RV-4, and it looks like a fun little plane. He did a fantastic job cramming everything in, using the cheeks behind the firewall for some stuff (firewall space is limited).
My impression of the RV-4 is that it's probably the most "fun" non-Rocket RV to fly, but not necessarily the most versatile. If you want to equip the plane for IFR, be able to tote around porky passengers, make long cross-country trips, and have a little more room for...well...everything, then the RV-8 may be a good choice. If you like more of a challenge in the construction phase, and you're not gonna go nuts on equipment and avionics, then the RV-4 is cool, too.
)_( Dan
RV-7 N714D
http://www.rvproject.com