TAKE OFF FLAP SETTING

[Jim B]

I have been flying my Jabiru 2200 powered Sonex since September 2009 and have accumulated 317 hours on it. I built it with three flap setting rather than the two per plans. 99.9% of the time I take off with zero flaps. A couple of times I have used the first notch of flaps. Once off the ground my climb out speed is 103/104 mph IAS with somewhere around 700 fpm ROC depending on all the usual variables we deal with. I retract my flaps on climb out around 100 mph at a safe altitude. Now my question, How many of you routinely use flaps on take off?
Jim

[gammaxy]

I use 10 degrees on short grass fields especially if near gross weight since it seems to get me off the ground quicker and I raise them once I'm climbing out of ground effect.

The flaps help takeoff and fly at a lower speed, but once the airplane's going fast enough that it doesn't need the flaps, it'll climb faster without them.

I don't think you're getting any benefit by keeping them out until 100mph, but I don't think it hurts too much.

[Corby202]

I use the first stage of flap if I have a heavy passenger. The runway I use is a little bumpy and so I figure if I did did bump into the air earlier then I had planned it would be safer.
Usually no flap and climb out at 80 knots.

[tonyr]

Hi Jim,

I have a 2200 Sonex TD, and my hangar neighbour also has a 2200 TD.

Your observations appear to mirror ours..

I always use 10 deg of flap for takeoff, as does my neighbour, regularly getting off the deck at about 65-70 mph levelling to accelerate a bit, then climbing out 75-85 mph.

I usually retract at around 300' and continue climbing at about 92-95 mph to keep the rear cylinders cool.

No VSI configured on my Dynon at present so not sure of the rate of climb, probably anywhere from 700-1000 fpm solo. (I have a 54 - 48 Sensenich)

Monitoring rpm, CHT and EGT tends to determine my climb rates more than aiming for a particular number.

Most of the strips I fly out of are 2000' grass strips and even when using 10000' of asphalt, I still use flap.

(I've converted all my figures from knots and metres for you uninitiated people)

I have 3 positions on my flap quadrant as well, if doing an baulked approach, using more than 10 deg of flap with the 2200 is not an option.

At another field nearby there is an Aerovee Sonex nose dragger, that routinely takes off without flap and the run is noticeably longer before they get airborne...

Something like 25-30% again to what I use.

Probably a technique/bad habit thing from flying trucks.. as I did notice that the pilot flying it did not apply a bit of back stick to increase the angle of incidence as they got close to flying speed, but rather kept the nose planted all the way down the strip.

Cheers Tony

[mike.smith]

I started flying my AeroVee Sonex with 1 notch of flaps for takeoff, but after a year of flying and trying different things, I found the ONLY time I got better takeoffs with flaps, was from grass or rough strips. Unless I'm flying off one of those surfaces I use no flaps. With one person on board I'm airborne at 36 kts in 800 feet. At gross it's about 40 kts.

I also used to take off by lifting the tail while building speed, but my take off rolls were always significantly longer, and I had to pull back on the stick to get it to break ground. Now I take off with no flaps, and leave the tail wheel on the ground. The plane takes off by itself, and in fact I have to set nose-down trim before I start my takeoff or the plane will pitch up right after breaking ground.

[peter anson]

I have always used one notch of flap on take-off, the theory being that if the noise suddenly stops the forced landing will be at a bit lower speed.

I also used to take off by lifting the tail while building speed, but my take off rolls were always significantly longer, and I had to pull back on the stick to get it to break ground. Now I take off with no flaps, and leave the tail wheel on the ground. The plane takes off by itself, and in fact I have to set nose-down trim before I start my takeoff or the plane will pitch up right after breaking ground.

When I first started flying the Sonex I used a similar technique because I was concerned about the sharp swing to the left when the tail came up, but a very experienced and highly competent pilot advised me that the problem with that technique was that it was possible for the aircraft to lift off before it was really ready to fly, something that could easily with a bumpy grass runway or a slight gust of wind. I changed to a conventional technique and coped with the swing by just feeding the power in more gradually.

Peter
Sonex 894, 342 hours

[Jim B]

All
Thanks for the feedback and new information on takeoffs. I think it will be beneficial to use one notch of flaps on takeoff with a passenger or on a bumpy strip. I have only flown from hardsurface runways with the Sonex. I have the factory provided wheel pants and just don't want to take a chance of damage from a grass strip.
Jim

[daleandee]

I think it will be beneficial to use one notch of flaps on takeoff with a passenger or on a bumpy strip. I have only flown from hard surface runways with the Sonex. I have the factory provided wheel pants and just don't want to take a chance of damage from a grass strip.
Jim

I fly mostly from pavement but do like to visit a few local grass fields. On the pavement with the 120 HP I find a "clean" no flaps takeoff works best for me. As pressure builds on the elevator I move the stick forward so that when it breaks ground it is at takeoff attitude. When lightly loaded it can leap off the ground quickly so be prepared. I do use 10º flap on grass runways. Tom Huebbe & John Davis both gave me some really good pointers on flying one of these tail dragging things. 8~)

About them wheel pants ... I've had mine off a couple of times because of small cracks forming in various places. I just repair with fiberglass and hit it with some plain white spray bomb paint. Hard to keep wheel pants looking great if you fly grass fields. But grass field fly-ins seem to be where the most fun is!

Dale Williams
N319WF @ 6J2
Myunn - "daughter of Cleanex"
120 HP - 3.0 Corvair
Tail Wheel - Center Stick
Signature Finish 2200 Paint Job
165.2 hours / Status - Flying
Member # 109 - Florida Sonex Association

[vwglenn]

No flaps in my 3300 on take off. I get the tail up with a little forward pressure before I lift off. I keep it in a three point attitude but just get that wheel off the ground. If I don't do that it'll yaw pretty hard once the rudder coupled tailwheel lets go of the earth. Climb out at around 110 on hotter days 85-90 when it's cool. I used to have three flap positions on my plane but the aluminum angle for the detent developed a crack right where the cutout met the stringer. Now I have... up, 10 degrees, and full down. I always pulled full flaps on downwind even when I had the extra position.

When I did the transition training in the aerovee Waiex with Joe, we did a little experimenting with the first notch on takeoff. Found that the plane would break ground quicker but that was about all it was good for.