I removed my floats and reinstalling the trike gear and I'm wondering what the rule is for setting the front wheel hight hight?
Should you set the wing incedence to the ground by adjusting the wheel hight?

Pop

Yes, the plane should sit level or very slightly nose up.

With any tricycle gear setup the fuselage should be relatively level. Excessively nose high or nose low will cause Problems nothing severe but enough to make the airplane not as much fun to fly.

An airplane with a nose high attitude will takeoff ok in most cases but will be difficult to acheve a two point touch down (a three point touchdown is not desirable with any tricycle). The nosewheel will tend to touch first causing the landing bouncys just like a taildragger with the main gear to far forward.

An airplane with the nose set to low will tend to glue itself to the runway requiring more elevator and/or airspeed to lift off and when it does it will jump off wildly.

John

I have found that you always want the nose a little low when setting on all wheels. If you have the nose high, you will find landings without excessive bouncing difficult and you may find the plane lifting off with insufficient flying speed resulting in the proverbial tip stall and cartwheel. A nose down attitude is almost mandatory if flying off a hard surface but you can get by with the nose a little high in grass.

If the nose is set low then the main gear legs will be inclined backwards, causing the point of contact of the wheels with the ground to be further aft. The other point of view is that the CG will be further forward relative to the mainwheels, so the elevator will have to produce more force to rotate the nose upwards. Really overdoing it will stop the plane rotating at all whereas just a smidegeon will still produce an abrupt take-off.

Actually, the behavior you describe will be caused by the wing actually creating lift in the downward direction because of the negative angle of attack. It would have a little to do about the shift in gear location vs cg location, but it is such a slight change that it is not the main cause of the plane "sticking" to the runway. Even a couple of degrees of negative angle of attack and the airfoil will produce lift towards the ground and you will have a tough time getting it off. However, when you do get rotation, it is followed by the jump in the air because you are probably going very fast and the wing all of a sudden creates a bunch of lift straight up, thus jumping off of the runway.

I designed a high lift plane with a very high lift experimental airfoil, and on the first prototype, the plane was at a slightly negative angle of attack. This was not on purpose, just a construction error and we decided to try it out anyways. It would not leave the runway at all, even after a 300ft roll at full throttle. We then adjusted the landing gear a little and got it to level and the plane took off in 10 feet. Just goes to show that a couple of degrees of angle of attack can make a difference.

No matter what the question there shall always be pros and cons. So much depends on your style of flying. Here is a suggestion for you. Set plane up so wing is at zero angle of attack. try it. Next change to slightly smaller nose wheel giving negative AOA, try it. Next use slghtly larger nose wheel now you have positve AOA. This should enable you to choose how you like it. Personally I think much of this is B.S. I don't find it at all critical. I do prefer slight negative though.

As you can see from this thread and an almost identical one http://www.rcuniverse.com/forum/fb.asp?m=9154423 currently running in the beginner forum, there are three totally different opinions.

Try all three and you'll know which is best for you.

Or convert to tail dragger. Then you can go from nose high to level to nose low all on the same takeoff run or landing.

simple is almost always better.

The fuselage holds the wing and tail correctly for flight.
Adjust the gear so the fuselage is parallel to the ground and it'll be good to go. (humorous selection of words intended)


(didn't somebody already mention this..... )