The ultimate “project update”! Way to go, Brian... your airplane is beautiful!
The ultimate “project update”! Way to go, Brian... your airplane is beautiful!
John Evens
Arvada, CO
Kitfox SS7 N27JE
EAA Lifetime
Chap. 43 honorary Lifetime
Wow!! Seems like you had just started that build.
- Gary
S7 SuperSport Tri-gear
w/Rotax 912, Oratex, Dynon
For those interested in performance, here are some numbers derived from EFIS flight data:
Density Altitude: 8000
Flight test weight: 1175 lbs.
Flaps: 1/2 position
Ground Roll: 550'
Distance to clear 50' obstacle: 1017'.
Climb rate: 1300 fpm at 71 mph.
These numbers are with an inexperienced Kitfox pilot making no attempt to extract maximum performance. I'm pretty happy with the performance, and look forward to developing the skill required to expand the envelope.
--Brian
Flying - S7SS
Nice Brian! Thanks for posting the numbers. Refresh my memory on your engine again? Non standard 914 turbo, correct? HP?
Great Job!
Clark
Flight test is going slower than I'd hoped. I'm only 7 hours in. Between work travel, kids' activities, teaching a Private student, and weather, it's harder to find flight time than build time! It's 30 degrees and snowing this morning. Go home Spring, you're drunk!
Some notes:
-The performance is a lot of fun. At SAF, I can make pattern altitude inside the fence. On a touch and go, it's airborne before the throttle makes it to the stop. Really fun.
-The oil temps on the 914 at ~40 deg and 9000'DA get warm. At Max climb power and Vy, I would overheat within 2-3 minutes. Of course when you're climbing at 1500 fpm, you don't need to maintain that for long to transition to a cruise climb. If I push the nose over to 85 mph, it cools right down, and I still climb at 900 fpm. As summer approaches, I may have to think about improving cooling.
-My empty CG is 9.7. Solo with full tanks puts me at 11.7. At that CG, you run out of aft trim way before approach speed. I put 50 lbs of ballast in the aft cargo bay, putting the CG about 13 inches. It's a different airplane now on the approach. Much easier to land.
-No left turn tendency mitigation is incorporated into the design, so like most, mine has a slight left tendency. Hands off the yaw is .5 to 1 ball width to the right, and it rolls left ~ 1 deg/s. I'll add a rudder tab to center the ball, and then adjust the washout.
-Stalls like a kitten! Stalls are non-events.
-Full flaps sucks. The controls get 'weird". Hard to describe, bit it's more than extreme adverse yaw. I'm pretty sure airflow over the H stab gets turbulent.
-Its fast. The turbo does it's job. 130-135 mph at 11000' DA. (914 w/912 ULS cylinders, Airmaster prop w/ 70" WW blades.)
--Brian
Flying - S7SS
Thanks for the update! Sounds like it’s fast and climbs great also! What ideas do you have on cooling? Thinking of lowering my oil cooler all the way down to sit flush with the bottom of the radiator. Wonder about an oversized oil cooler?
Dustin Dickerson
Building 7ss STI x 2
Oratex
29" shock monster
EP912STI 155hp
Garmin
N33TF......FLYING!
N53TF......FLYING!
If I can reasonably manage temperatures by lowering the nose and reducing power, I won't change anything. There's no reason I need a maximum performance climb to 3000' AGL.
If I do struggle to control the oil temps, a bigger oil cooler is an obvious choice, but finding one that fits where the current one does might be a trick. It would need to be wider, but not much taller, and the cooling air inlet NACA would need to be modified to accommodate different ports. It's probably a pretty big job.
Thomas used an oil/coolant heat exchanger on his Shark, so that's another option I would consider.
--Brian
Flying - S7SS
Hey Brian, great to hear from you. Thanks for the report and keep them coming! I'd like to know how it does as the weather warms into summer.
Clark
Dustin Dickerson
Building 7ss STI x 2
Oratex
29" shock monster
EP912STI 155hp
Garmin
N33TF......FLYING!
N53TF......FLYING!