Congrats Tracy!

Bryan

 

 

Today there was nothing left to do on the RV-8 but flight test it.

 Very hot day (93 F and high humidity) but ground tests of the cooling system had gone so well that I was confident of cooling in flight.   Installed the radio and transponder in the panel (which for some reason I had neglected to do until this morning) and they both worked with no problems, which is always a surprise. 

High speed taxi tests had already been completed and the P-factor was no worse than the RV-4, in fact I think it has less.  This may be premature because I haven't done a full throttle takeoff yet.  The RV-8 has 1.25 degrees right offset which I think helps a lot.  The RV-4 has no offset.  First flight was done without wheel pants or main gear intersection fairings.

Just to make sure there were no surprises, takeoff was done at the same fuel flow as the RV-4 at WOT.  I didn't note the manifold pressure but the throttle quadrant was barely over 1/2 throttle.  Ground run on the -8 feels more stable than the -4 with considerably more rudder authority (it's physically bigger so no surprise).   The plane broke ground at about the same point as the -4 but it feels like it levitates off rather than rotates off.  Probably due to the higher wing incidence on the ground than the -4 with the short gear legs but also due to the longer wing.  I had extended both wings by about 18" so the wing loading and span loading are less than on the -4.   It has about 13% more wing area than stock.  This was actually the second time the -8 had air under the tires since it had floated off ground about a foot once before during a high speed taxi test.

Airspeed was increasing rapidly after lift off but the ASI was not matching the visual ques.   Normally I expect to see 120 mph at the end of the runway but ASI shows only 80. Too late to abort but the airplane is climbing & sounding very nice.   I had been doing a lot of seat-of-the pants takeoff and simulated dead stick landings (in the -4) in anticipation of today's tests so I would feel comfortable in the event of partial or complete panel failure  (Blue Mountain EFIS1 with only a standard ASI for backup).  Climb to 1000 feet felt effortless even after throttling back to 8 GPH.  I notice that I'm hunting for information and not absorbing much due to the very different instrument panel.   Remembering that the EFIS1 has the primary ASI in a speed ribbon format I hunt for it and see 0 MPH when I finally find it.  The EM2 shows the same airspeed as the steam gauge, now about 100 MPH.  First squawk of the flight and this means I will do the first landing sans airspeed indicator.  I can't seem to locate the GPS ground speed on the display either.  Glad I did all that practice.

Time to settle in and start evaluating engine performance.  I had taken off with the engine fairly warm so I was not surprised to see oil & water temps nearing 190 F after climbout.   I continue collecting data hoping the temps will start coming down but it is soon apparent that they are stabilizing at about 200 on both oil and coolant.   Very disappointing, since they had been well below this on the ground when at the same fuel flow I was currently flying at (I had backed it down to 5.75 gph by this time).

The plane itself is flying beautifully.  The aileron trim is able to trim out a very slight left wing heavy tendency and the ship feels like it is gliding through the air effortlessly.  Again, no surprise, the plane feels just like an RV (Magnificent!).  At this speed (guessing about 135 mph) the roll response  is only slightly slower than the -4.  The ailerons were extended with the wing so the RV feel has been preserved.  I've completed a wide circuit of the pattern and in position to make an approach so I throttle back and I can immediately tell that the glide ratio is significantly higher than the -4.   The longer wing is having more effect than I thought it would even with the heavier engine.  This -8 with a 20B ended up weighing about 70 pounds more than the average one equipped with an 0 - 360 and fixed pitch prop and about the same as one equipped with an IO - 360 with constant speed prop.  All the attention to weight control has paid off.  I throttle up for a go around and the FBW throttle responds well, no detectable throttle lag at all.

The higher than expected oil and water temps are distracting me from data gathering (Rats, I haven't had time to replace the EM2 with a data logging EM3 yet) so I make a few more circuits of the field and setup for an approach.  I crank in more flaps early to kill off the airspeed and excess glide ratio and intentionally do not look at the ASI to avoid being confused.  Wheel landing touchdown is perfect and now I glance at the ASI and see 40 MPH.  Obviously wrong.

All in all, a great first flight.  The RV-8 is going to be exactly the airplane I was hoping for.   Still a lot of testing and tweaking to do.

Tracy