Specs:
Badland F2 kit with Polini 303
Eprops 2 blade 160cm ground adjustable prop
Stewart Systems with Superflight 104 fabric
254# empty weight
General Flight Characteristics:
The aircraft is very predictable in flight. Maintaining straight and level flight is a non-event. Two fingers on the stick and and course correction or altitude control is maintained. Rudder use is very similar to other fabric airplanes that I have flown (Think Piper Pacer/Super Cub/Super Cruiser/J4). An hour long flight is very enjoyable with no fatigue from aircraft control workload.
Ultralights in general:
Coming from general aviation aircraft that cruise between 2-6 times faster a big difference noticed here is the small speed envelope that the aircraft operates in. It’s a new concept for me to be cruising about 25 knots above stall speed. The aircraft flys well, but a small speed change is quite noticeable in how the airplane feels and responds. Most of my flight time is spent between 40 & 50 knots. I admit, seeing 39 knots on the airspeed while climbing away from the runway was startling for my brain. However, the wing was quite happy with positive control and good response. It should, as this is the Vy speed for this wing. Keep in mind as well, Vne is 70 knots. I have seen 60 knots in a power descent, but have not exceeded 60 knots yet.
Back to F2 specific.
Slow Flight:
All of it is slow flight
. No seriously. From 35 knots down the airplane starts to feel slow, albeit it is only settle here. 35 knots is Vx. Note, only 4 knots from Vx to Vy. At 30 knots the angle of attack is quite large and the wing is throwing clues your way that critical angle of attack is knocking on your door. At 27 knots the wing is now screaming at you for a lower angle of attack. Stalls so far have recovered very quickly as soon as the angle of attack is reduced. I however still struggle with pushing left rudder input due to the counter clockwise rotation of the engine. So many hours of clockwise ga engines have cemented right rudder into my muscle memory. Performance:
I am very please with takeoff and climb performance. I am going to work on building performance charts as I continue to fly. Rough numbers….. 200-250 feet on the takeoff roll with a normal takeoff and little to no wind. I am not forcing the airplane off as early as possible. If pushed harder this distance could be shorter by maybe 10% or a little better. At this time I can say that the demonstrated unstuck speed is 28 knots. What is very noticeable is headwind component. A 10 knot headwind is dramatic. It is about 33% of the airplanes needed flying speed and you aren't even moving yet.
Climb rate is around 500 foot per minute from 1500msl to 3000msl. This is with the throttle retarded about 400-500rpm. I do not run WOT (Wide Open Throttle) any longer that necessary after departure. This is simply me looking for engine longevity. I have not had the airplane over 4000 feet msl yet.
Cruise around 48-50 knots. Engine seems to like 7100-7300 rpm or so. Remember, 4000 rpm and below is basically idle for my Polini 303. Red line rpm is 8400. I have a 3.2 gear reduction so 7200 engine rpm is 2250 prop rpm. 8400 engine rpm would result in 2625 prop rpm.
Glide. I did one glide. I need to do more. Especially practice with power off 180 landings. That being said 40 knots with the power at idle produced a glide that felt close to a cessna 172 or a piper warrior (warrior with a taper wing that is. IMO the Hershey bar wing is a poor glide wing). When slowed to around 35-37 knots the windmilling of the propeller slowed enough to disengage the clutch to the engine. This results in the engine speed dropping from 4000 rpm (windmilling prop driving the engine) to a normal 1500-1600 rpm idle and a decrease in drag from the prop windmilling. I need to experiment here more and start recording some numbers.
Landing. It’s very enjoyable for me to point at the 500 foot markers, land a wheel landing, and still need to taxi forward to get to the 1000 foot marks. It’s ridiculous, ridiculously fun that is. With minimal braking a wheel landing is roughly 300 feet. I feel that 200 is within the aircraft's abilities, I simply have not pushed it that hard. 3 point landings will result in shorter ground runs of course. I have performed 1 three point landing in the grass. Without paint markings I can’t provide a ground roll distance accurately. I can offer this….. the particular grass runway I used is a private strip that is 1600 feet long with obstacles at both ends. I have gone into this runway with my RV4 in the past. Using my F2 with an approach speed roughly 25 knots slower than the RV4 I felt like I could touch down in the F2, take a nap, and wake up before we got the the end of the runway. Super comfortable due to the lower speeds involved. I am on 13 inch tires and they did much better in the grass than I had anticipated. Maybe the spring suspension is secretly taking credit here. Either way, I am pleased.
Thoughts on wind limits. I am not to the point that I can say the limit is x amount. I landed in wind that was 40 degrees off runway with 14 gust 19. I did not intend to have that much wind when I went out, but the wind went from near calm to 14G19. This results in a cross wind component of 9G12. Landing was very doable. Understand that I have removed the rudder to tailwheel steering linkages during the build phase. I wanted to be able to turn tight on the ramp and or near hangars/parking spots. This means there is a little more work to be done to keep the airplane straight on the landing roll out and taxi. At this time that is enough cross wind until more hours are in the logbooks. When taxiing directly across that wind on the ramp it takes judicial amount of brake use to keep directional control due to the free caster on my tailwheel. Current personal limits 15 knots total and 10 knots x-wind.
At the end of the day it takes me about $12 of avgas and maybe a $1 of two stroke oil to fill the fuel tank back up. I see a fuel burn of about 2.2-2.5 gph. Then I put it in my trailer and have no monthly hangar bill. This airplane has given me a very enjoyable path back to the skies without a medical while being very economical to operate.
LM
