Hi, I'm practicing taking off with my LT-40 and my instructor told me to hold full up-elevator at the beginning and relax it to about 1/4 up as I throttle-up until rotation.

This is different from what I learned from book. The book says: throttle up gradually to full throttle and apply a littel bit up-elevator when the plane gains enough airspeed and begins to rotate.

However, the field where I fly is grass and bumpy. So, I wonder if I should use a different technique. Honestly, I don't feel very comfortable with the manuveur of applying full up-elevator first and then relaxing it to 1/4.

I used to be able to take off from the same grass field with no problem. It just happend last Sun. Maybe the landing gear and the nose gear wire were bent during hard landing. My instructor said I should adjust the angle of the nose gear up since it appears the nose points too much to the ground. If I so, will the trainer leaves the ground before it has enough airspeed? I setup the nosegear according to the instruction book from SIG.

Any suggestions?

Thanks.

ME...

I am not an expert on this but I also fly from a grass field. Last Sunday I watch a couple of the LT-40's at our field and they didn't seem to have many problems with the grass.

I have found that if your model doesn't sit high enough for the prop to clear the grass, you're gonna have problems. I fly an Avistar which uses the trike landing gears. I wasn't happy with the height of mine so I closed the gap between the tires on the main gear and put a longer nose gear on mine. Now it clears the grass nicely. I am also going to change the stock tires out and go with something like 3" tires to give it a bit more gound clearance.

As far as using some up elevator, I use full up until I am positioned and starting to roll a bit then relax until I am satisfied that it has enough speed before adding a bit of up again. If your model is pretty level sitting on the gound, I would think that you could get a good long running start before rotating.

The best suggestion I would offer is ask around, listen to what the more experienced flyers have to say and experiment a bit until you find a method that you are comfortable with. I would venture to say that if you ask 8 flyers how to do something, you'll get 12 different answers.

Good luck,
Crash Master
(Crashing with finese is an art)

The method for elevator use as descibed by your instructor works well for a tail dragger. Trike gear airplanes are very different. The LT40 is very stable because of the placement of the landing gear and the width between the wheels. With a rough grass field, the first thing you need to do is to have proper size wheels. Too small wheels try to push through the grass rather than ride on top of it it. This keeps the plane from gaining proper speed. On an LT40 you will need 3" wheels for the mains and 2 3/4" for the front steering wheel. I would get Dubro Lite Weights. For the take try this: elevator at neautral, throttle up to full and steer straight down the runway. When you have reached the 1/2 way point on the runway start to add in up elevator. The plane should leave the ground nicely followed by a smooth climbout. Holding in up elevator right away keeps the plane from gaining proper takeoff speed and the plane may also take off before its ready making control sluggish until it gains speed. Hope this helps, Fast!

What the fright instructor was teaching you is called a soft field take off. It is a valid way of taking off from rough or soft fields.. It just gets you into the air quicker.. it is the same technique with both tail wheel and trike gear airplanes.. you hold full up elevater and throttle up pretty quickly.. It gets you off the ground quicker.. just be carefull to get the nose over as soon as you get off the ground to let yourself accelerate.. it is not as safe of a method because of the slow rotation speed, but easier on the airplane when flying from a rough field.. I agree with the previous post about the larger wheels too. it will help alot. Good luck!

Cheers,

FW

We fly in at sod farm so you never know what length the grass will be. We had an LT 40 out there last week and he had to hold full up elevator to get the plane off the ground. He couldn't get ground speed any other way. Just think of you tri gear becoming a tail dragger (you just want the nose up and the prop out of the grass). The best solution is some big ol' tires! The other part of the problem is landing. As soon as you hit that grass if you nose isn't high you are going to flip over on your back and hope you didn't snap off your rudder! I running 3 inch tall tires and I'm going to move to 4 on my tail dragger.

Yup,
Like the last post said, listen to your instructor. Things may have changed at your field (taller grass, your nose gear may have bent back slightly, etc) since you first started learning there. Even though you have a tricycle geared plane, the drag of tall grass, too small a nose wheel, or slightly bent back nose gear can all cause the nose of the aircraft to assume a slightly "negative" angle of attack as you try to accelerate. This "digging in" so to speak, of the nose can at the very least cause so much drag that the plane stops accelerating before you have suficent safe airspeed to rotate and lift off, and in the worst case, (I've seen it happen with a soft/flexible nose gear) cause the prop to start mowing grass (big time power loss) instead of lifting the plane off.
As another poster above said, what your instructor has described to you is a soft field takeoff procedure, also used in some full scale planes. If you think about it, by holding less pressure on the nose wheel (up elevator), or even holding it slightly off the ground, there is MUCH less ground drag (1/3 of your wheels are almost or totally off the ground). This keeps not just the nose wheel, but also the prop well clear of the grass and allows you to accellerate the plane faster and also achieve a HIGHER ground speed, than when you were "plowing along" with a negative (nose down) attitude.

With this said, it is true that you should slightly reduce the up elvator as the speed increases so that you do not lift off too soon into a stall, so this type of takeoff DOES make you think a bit more than what is described in your planes manual. Also, you MAY be able to accomplish something similar by just going to a slightly larger diameter nose wheel that holds the nose at a slightly positive angle of attack, but then you will also still have to have enough power on hand to handle the drag of the nose wheel in the grass on the takeoff roll.

Hope this all helps,

Lee

If your nose is pointing down while the plane is at rest, adjust it so that it is level or pointing slightly up. This will NOT give your plane a tendancy to take off too soon. Rather it will allow the plane to gently lift off the ground when it has reached proper flying speed.

We have a grass field as well.... I ran 3" foam wheels on my trainer and would not give any elevator until it reaches atleast 1/2 to 2/3 down the field and it would take off great.. I agree with the above about pulling up at taxi and down the field. That is what we do with taildragger's... Hope it helps and practice..



FLY IT LIKE YOU STOLE IT !!!!!

A beginner should always listen to and follow the instructions of their flight instructor. These people are telling you what works based on years of flying experience. I have been an instructor for around 14 years and have seen and flown just about every type of trainer that has been made during that period. I have never ever consulted the student's manual before flying their trainer. Point being is that your instructor already knows what works and does not have to read a manual first.

I haven't flown on grass for a year, but when I learned last year, it was on a grass field. My instructor had me do the same thing. The only difference was that we had somebody hold the plane, ran up the engine to full throttle, and let go of the plane with full up.

My buddy uses his foot.

I have flown models for around 12 years and have flown full size planes from a cessna 152, 172 trike landing gear on both of those and a cessna 170 which is a tail-dragger, and I have flown many types of model planes from trainers to giant scale aerobats, Do what ever is comfortable to you but also listen to the more experienced guys, if it dont work for you dont do it anymore, the point of all this is to have fun and just fly the plane. I always use up elevator when taxiing, you never know when the nose gear might hit a bump and try to tip over or on a taildragger it keeps the tail down to control steering...on a soft field takeoff you have to keep the -- nose wheel light for many reasons -- and you keep the nose up on takeoff roll (flaps down on) until you reach takeoff speed and lift off lowering the nose a little and gaining speed and your off ( mind you that is a full scale takeoff ), but do what works for you, later

You might want to try using a different prop. If you switch to a larger diameter with less pitch, it should give more thrust and get the plane off the ground sooner. Good luck and let us know how you make (or made) out.

I run a 13x4w (Thunder Tiger .54 4 stroke). It isn't a speedster (I was never into high speed anyway) but it has tons of torque. I love that prop and so does my plane!

If it is a rough grass field, which it sounds like it is, with a forty size plane you will have to give it up elevator until you gain ground speed. As your speed increases, slack up on the elevator. You want to get the weight off the front end and onto the main wheels. Putting the plane up higher on the nose wheel won't do it by itself. By giving it full up with most of the pwer it gets the weight off the front and helps the ground control. Try different size wheels as well (bigger).
Good Luck

I too am lerning with an lt40 on grass and had grass mowing problems to begin with. I had an 11" prop which bogged badly on takeoff. I switched to a 10" which helped (but is not a recommended prop for my 46 LA). I've also taken the 2.75" wheel from the nose (along with another one I bought from the hobby shop) and moved those to the rear and took one of the 3" rear wheels and moved it to the front which gives it a more nose up attitude. I haven't flown it yet since this mod, but it is something you might consider. Whatever will reduce my need of 409 and paper towels to remove the green from the whole plane.

Wayne

Get some big tires
Listen to your instructor

The big tires will help alot.