Hi everyone, I've got a Seagull Decathlon that I've flown with a few times (my second plane and first taildragger). Each time I struggle taking it off (fly and land just fine). I can't keep the plane tracking straight. I know taildraggers tend to pull some, but is this one tougher than others? Should I be flying a different tail dragger?

Couple tips I received: take the spring off the tail wheel and replace with straight rod, bigger wheel on the tail. I love the set-up I have with this plane, but I am getting highly frustrated at this point. Thanks in advance.

Not sure if this is the trouble or not. But I see so many people throw the throttle wide open from the get go & they take off across the runway. I have always found that if I take more time to take off, ease the throttle open gaining speed till I reach full throttle that I have less trouble making it track straight.

kengee,

On a plane like yours, here is what I do. I position the plane on the runway, and from idle hold full up elevator and slowly increase the throttle while letting off the elevator. When I reach 1/2 throttle I'm usually off the elevator (elevator at its neutral position) and the plane has enough speed for the rudder to be functional. This keeps weight on the tail wheel so there is positive steering/directional control.

Do you have toe-in on the landing gear? If the wheels are straight ahead or have toe-out this could be causing it to be squirrel on the ground.

Hogflyer

Kengee, when I first started with the tail draggers, before I soloed, I had the same problem you are experiecing. Here is what I learned.

1 Throttle management is the single most important thing in a straight down the center line take off. You have to get the rudder flying and controlling the direction of the plane before applying full throttle. Our field has a 500 ft paved runway and the entrance from the flight line to the runway is at about 40% of the length from the start on the left. I really prefer take offs and landings when the wind is from the right as it give me a longer take off roll and if I touch down near the circle, I have a longer way to overshoot and still not get into trouble. I roll out to the center line and as I'm making my turn to line up, I start very slowly incerasing throttle. All the while, I am keeping full up elevator to keep the tailwheel down. As the plane picks up speed, I keep slowly increasing power. After about 50 to 75 feet of acceleration, I release the up elevator and keep adding power About this point, the rudder has control and I'm at about 50% throttle. From here you can more rapidally add power without verring to the left. However if you jam full throttle at this point you may make a left turn in the process.

2. setting up your plane is important. The tail wheel needs a stiff, but not necessarly a ridigid coupling to the rudder. I use a lot of the sullivan tail wheels and I use the smaller, stiffer spring. I also use the 60+ size one as the tail wheel wire is stoutter and it holds the plane on corse better. The 40 size one tends to fold to one side or the other under full up elevator on takeoff. Go to a paved and smooth area and with the radio on and controlls in netural, push the plane into the wind and watch how it rolls after releasing it. It should roll straight on the course you pushed it. If it is rolling off to one side, bend the tail wheel axel to straighten out this roll. It is important to do this with the radio on and after the plane has been trimmed out so you are not adjusting the wheel to a rudder that is not centered for flight.

3. make sure your engine has the right thrust , IE zero or a bit of right thrust depending on the design of the plane. Follow the plans here. If the plane is built to plan and the motor is mounted straight to the firewall, this is the last area you will tweek to try to fix your takeoffs.

4. Some birds just don't handle well on the ground. The short length compaired to wing span lends its self to bad ground handling, IE the Cubs are know for bad ground handling, both the models and full size I have been told.

5. If all else fails get a gyro and put it on the rudder. I did this for a couple weeks while I was still on the buddy box and it helped the takeoff considerably. I found it was effecting some other things, so I pulled it. I had a cheep one that didn't allow me to control the gain from the radio and had to make adjustment on the ground. If you go this route, get one that you can shut down the gain after takeoff and turn it back on for landing.

Practice, practice, and more practice is the key. Touch and go landings don't count, land, taxi back the pits and do a U turn and take off again. Until you get the hang of it, 10 to 15 takes offs and landings a day is a good goal. More if you can get the runway tiine and have the time.

Don

Thanks for the advice everyone. I have been told and do slowly build up on the throttle, I'll try maintaining the wheel down a little longer since we have plenty of runway. I think tweaking the landing gear is in order too. I will try the more rigid spring and the 60 size tail wheel. And I know the main gear toes out, so I will change that too. Again, thanks for the advice.

One thing have have to dissagree on is the importance of the tail wheel, springs are fine and the tail wheel is really more for taxiing around, if you are having problems with the way it taxies change it.
When taking off the tail wheel only contacts the ground for the initial roll out and that usually is not for a very long distance.
Most of your take off roll will be on the mains only. Offset thrust on the engine and good rudder control are the major keys.

Another thing to concider is the type engine in your Decathalon. 4 strokes swing larger props and will want to pull the plane left a little harder than a 2 stroke. The most common ways to compensate for this have already been stated above, and are all of equal importance:
Tow in on the landing gear
Even accelleration
Rudder control
As far as the tail wheel goes, half of my planes use a skid plate instead of a tail wheel. The only thing you need a tail wheel for is taxiing. Other than that, it's just there to keep the rudder off the ground.
Do not put a gyro on the rudder. If need be, some radios will allow you to mix the rudder with the throttle. Gyros are for helicopters. Putting one on a plane is like saying you don't want to learn how to do this, so you'll just put it in automatic. Gyros on airplanes are not learning tools.

One thing that I have heard is try to take off in grass, I know on some taildraggers it helps make take off's a lot easier.

Jon

Like many other posts I ease on, especially with my big gassers, they opull very hard if I slam the throttle, so throttle managment. I don't see the need to change anything, just live with it, learn to fly it, it will make you a better pilot in my mind, make you quicker to react. One of my yaks has a twisted tail wheel from landing to hard so takes offs I put down elevator (very little) so I have rudder athority. But I have been flying for awhile and I don't fly airplanes like what your talking about. Have Fun!

A high-wing taildragger with close coupling can present a challenge, as many Cub owners will testify. The Decathlon is no exception. The Seagull, from my readings, behaves more like a clipped-wing Cub (correct me if I'm wrong), which has less difficult ground handling and takeoff characteristics. I have a Hangar-9 Tango that I have flown several times, and it has a nasty tendancy to torque-roll if the throttle isn't managed carefully. Whether it requires more skill to get off the ground than a Decathlon is currently beyond my knowledge. However, I will post an update of my observations when I get my Lanier Citabria (similar to a Decathlon) on its first flight.

NorfolkSouthern

The main gear can be shimmed, and it helps significantly.

The speed with which you roll the throttle in is really important with this airplane. I taxi mine into position and basically begin to taxi it down the runway. A couple of click more throttle and it'll build takeoff speed all on it's own and steer just like it did taxiing. Roll the throttle the rest of the way and it's flying. The picture was taken back in 2006. It's still as pretty today. And will go flying soon. As for the shimming..............

To begin with, it was a tad easy for a bump or rock to divert the taxi. I located the CG with the hang-it, and string-it method to see where it was both longitudinally and latitudinally and then figured what the angle was to the tires' point of contact with the ground. The design layout isn't generous with that angle. So I shimmed mine.

You can simply run a strip of wood that holds the back of the gear away from the fuselage. But I decided to make a wedge plate the size of the gear center piece to support it entirely. Tell ya' what. I'll go get a picture of that.......... brb

The plate is just a scrap of decent plywood. Liteply wouldn't be worth using as it'd probably crush. I just cut a piece that fit the space and sanded it into a wedge. Didn't measure the angle at all.

Sometimes, just a little bit works great. This did.

I painted it with surfacing resin when I was fuelproofing the nose of another ARF that was raw wood. You could also wrap simply Ultracote it. That's all that was under the gear center before.

It was easy. Took maybe 10 minutes.

IF your wheels are toed out, that alone could be a lot of the problem.

But there's one other thing I would like to point out about this plane - Make sure you have a good amount of speed before you let it get off the ground.

This plane has driven a lot of people crazy because they get it off the ground and it immediately goes into a hard left turn which they can not recover from. This is a simple case of taking off before it has good speed.

It is a deceptive plane because it LOOKS like it's an easy flier that will float like a Cub, but it's not. It is a highly aerobatic plane and needs speed to overcome the engine torque.

This is one of the more difficult tail draggers to takeoff. You picked a doozy as a first! Do not despair, you have gotten some good pointers in this thread. Once you get the hang of this one, all others will be a snap (no pun intended). Stick with it.

While I agree with the slow roll on of throttle and use of right rudder, the last thing you want to do is keep the tail on the ground for a prolonged period. You want to get the tail into the air as soon as possible and keep it there in while the airplane picks up speed. When the tail is "flying, it moves the landing gear closer to the center of gravity and is much more stable than when the model is in a three point stance. With the tail in the air, taildraggers steer about like any nosegear model.

On some models, I find that adding down elevator trim makes lifting the tail into a proper stance during the takeoff roll better.

Generally, having the gear too far forward makes a plane more likely to ground-loop, if the airplane has this problem you will have great difficulty. Airplanes designed by someone that flys from grass are usually forward of ones designed for pavement. Pick the tail of the plane up. If it is extremely heavy, you will have problems.

Thanks for the additional input everyone. I have made a note about the shimming of the front gear. I have noticed that it does get bounced onto a new line fairly easily. More than my skill is able to keep in check. I have had a couple of the instructors fly it and ok the set up so that should be ok.

I do have a four stroke engine in it, so that might make it a little more difficult (but the engine is the best part about it, a ys63, and runs perfectly). I'll definitely keep working at it, and hopefully with a couple of these ideas and practice I'll get it. Here's hoping for good weather next weekend.

I landed my Venus II one day and the landing was a tad long. So, I turned it around and started to taxi back to where I was standing.. it was about 100 yards away... (yeah, I know.. don't remind me of my landing skills on that one..let's just say it was windy, ok? ).

Well, I have a non-attached tail wheel on that plane.. meaning that it free-floats around, so all steering is done by the rudder, and it usually needs a bit of help from the prop wash.. yeah.. well, while taxi'ing back, I had the elevator full up to keep the tail wheel down , out of habit, and then the darned thing went airborne as it was headed directly toward me. I immediately cut the throttle and put it back on the ground.. and looked around to see if anyone was watching.. oops.. scared the hell out of me!!! I guess I had to much throttle on there, ya think? [X(]

CGr.

Learn to love the rudder. All airplanes and taildraggers in particular require throttle and rudder management. Don't depend on the engine offset to make up for torque and P factor. If you will practice using the rudder to overcome the tendancy to pull left, you will learn to appreciate takeoffs, and not look at them as a necessary function to flying.

Bill, AMA 4720
WACO Brotherhood #1

Engine offset is not just for overcoming torque on takeoff. I agree you should learn to use the rudder but some offset helps the plane preform better in a number of situations not just takeoff.

A couple of very easy things to do which help a LOT...

- Adjust the tail wheel so that when the sticks are centered and your rudder is centered the plane will roll but angle slightly to the right... say 1 ft over a 10 ft travel. This will help offset left yaw as the plane starts out initially.

- Adjust the tail wheel so that the plane sits more level on the runway. This has a dramatic effect on initial yaw on run-up.

You may still get some left yaw, but it will not be as dramatic.

If the plane also seems to yaw to the left as you run up the throttle while it is in the air, you may want to mix a very SMALL percentage of throttle mixed into the rudder. 4% is often enough.

Doing all three helps a lot to keep the tracking straight, especially when coupled with the Toe-in suggestion.

One of the guys at my club has that plane and had similar problems. During take offs the plane had a mind of its own He added a couple degrees of right thrust and it was fixed his problem.

I have just went to my "second" plane...4*40....taildragger configuration.... after SUperStar 40 trike configuration.......I spent a day taxiing and making takeoff runs but did not get airborne in order to see how she handled on the ground.Full up elevator at idle....open to 1/2 thottle.....feed in slight right rudder...back off elevator to about 1/3.....zoom tracks staright and JUMPS off the ground in 25'-30'..........OS .46 AX pulls it no problem.