July 13, 2008
I've been busy with the Phase 1 flight testing on the Miss'ippi Mudbug (N57EN). I now have about 15 hours on it and let me say that every time I fly it, I fall in love a little more. This is truly an awesome airplane. The Mudbug is equipped with a Bob Barrows O-360 engine, de-rated to burn 93 octane mogas. It produces about 180HP. It has a Sensenich fixed pitch prop (76" diameter x 56" pitch). Empty weight is 1338 lbs with a CG of 11.8". I weight about 265 lbs and the full tanks (52 gallons) of fuel weigh 312lbs so my flight testing is somewhere around 1900 lbs. and 14" C.G., depending on the remaining fuel on board.
I'm flying from a turf runway and takeoffs with 2 notches of flaps (25 degrees) are excellent! Full throttle with the stick all the way back and then just ease it forward to just get the tail up, the next thing you know it's flying. Lift off is in about 300 feet with a 7 knot headwind and I start out climbing at 80 mph. I'm well over the 50 foot trees that line either side of the runway very quickly. After that I retract the flaps and I like to settle into 90 mph climb which yields about 1100 FPM at a density altitude of 2000 feet on a 90 degree summer day here in south Mississippi.
Power off stall speeds are as follows:
Clean - 50 MPH IAS
25 degrees flaps - 48 MPH IAS
40 degrees flaps - 45 MPH IAS
The stalls are very benign. In fact you almost can't tell its stalling. I wasn't sure at first if I was getting a full stall, so I kept holding the stick all the way back and the nose dropped only slightly below the horizon and it was just kind of mushing around.
I tried to complete my climb testing and glide testing but with these hot summer days its just too bumpy to get really accurate results. What I find is that the best rate of climb speed (Vy ) appears to be at around 85 mph and I would put best angle of climb speed (Vx) at around 70 mph. Best glide speed (Vbg) seems to be about 70 mph. where it loses about 500 FPM. I'll get some better numbers when I can get a nice smooth day to try it again.
I like to land with 2 notches to 3 notches of flaps depending on how high I am on final. I keep the downwind in tight and do power-off approaches, cutting the power on downwind just when I'm abeam the desired touchdown point (we don't have numbers on the turf runway). I then establish and trim for a 70 MPH glide and turn base when the touchdown point is about 45 degrees off my left shoulder. Once I'm established on final I bring the airspeed back to 65 and put in flaps as needed to make the touchdown point. Sometimes I'm still too high and just end up doing a slip to lose the extra altitude. Between the flaps and slips I can pretty much place it anywhere I want it.
During the flare, there is plenty of elevator authority and I find that when doing the full stall landings, the tailwheel tends to make contact with the runway before the mains do. After touchdown, the Bearhawk rolls out straight and true with no tendencies to swerve. The rudder stays effective through-out the rollout so keeping it on the centerline is easy.
Video Taping a Flight:
This is my first attempt at video taping from inside the cockpit. This
is not a very good one, as this was hot (95 degrees) day here in south
Mississippi and the air was quite bumpy, so the video is kind of bouncy.
I was trying to handhold the video camera with one hand while flying the
airplane with the other. I was just pointing it in the general direction
and not even attempting to look through the viewfinder so wasn't sure what
I would have until I got home and viewed it.
The side window is open so there is a lot of wind noise especially when I move the camera near the edge of the window. I'm at about 500 to 600 feet AGL just about 5 miles inland from the Mississippi Gulf coast, very near Kiln MS where Brett Favre (retired Packers QB) is from. I'm cruising at about 2400RPM and 130 mph TAS.
I think I'll try to rig up a tripod on the backseat floorboard and strap it to the passenger side seat or something next time.
Anyway, here it is - sorry for the poor quality - I'm still working on it: Video Link
I can't express how incredibly enjoyable flying my Bearhawk is. On Saturday I spent about 2 hours just flying around over the country-side at about 500 feet AGL with the window open (so much cooler) and ended up following a local river. I came across some rafters gently gliding down the river, sipping a few beers (this very rural by the way). They waved up at me so I rocked the wings and then waved back through the open window. Southern hospitality at its best!