Question: How do I adjust the nose up/down angle on my trike gear model?

Answer: Generally the nose gear can be adjusted slightly up and down so that the wing is near zero incidence (level) when the model is on the ground. If the nose is pointing up, the wing will be flying when the model is on the ground and you will tend to porpoise up and down when landing. If the nose is pointing down a high ground speed and excessive up elevator is often necessary to get the model to lift off.  

To adjust the nose up/down angle of the model when it is on the ground, you can do several different things or combine these things to get the desired result.

Lengthen the gear leg by loosening the set screw in the steering arm and pulling the gear downward or shorten the nose gear by pushing it upward slightly and then reseating the set screw.

AND/OR

A different nose wheel can be installed. Increasing the nose gear diameter by 1/2" will lift the nose approximately 1/4" higher with respect to the ground. So instead of a 2.5" wheel for example, try a 3" nose wheel. Do the reverse if you want to drop the nose lower towards the ground.

AND/OR

A different set of main gear wheels can be installed. Decreasing the main gear diameter by 1/2" will lower the center of model by approximately 1/4" with respect to the ground and at the same time reduce the degree of nose down attitude. So instead of a 3 " main wheels for example, try 2.5" main wheels. Do the reverse if you want to drop the nose lower towards the ground.

Note that by combining changes to both the nose wheel and the main wheels, a great deal of adjustment can be done to the nose up or down angle of the model when on the ground.