You MUST do it right to avoid big first flight troubles
CG, Hang point, and Bar position on a Trike
There are several things to think about when setting up a new wing on a trike. If the wing is an exact replacement for the trike it is pretty safe to set up and go. If the Trike is not matched to the wing, it is important to do a proper job of setting things up before you attempt to fly the trike.
CG of the Trike
There are two important CG’s on a Trike. First the wing has a CG limit/location that needs to be considered separately from the CG limit/location on the trike. The center of gravity limits/location of the wing is determined by the manufacturer and or designer. The location of the hang block determines the location of the attachment point of the trike mast via the hang bolt, this attachment point must fall within the center of gravity limits along the keel tube of the wing.
All the weight of the trike and pilot hang below this attachment point via the hang bolt. This then, is the center of gravity of the Trike.
Everything hanging from this point is free to swing in any direction. The trike itself must be in a balance state while hanging from this point which will allow it to be in position for normal flight. This attach point is the center of gravity of the trike by itself, as well as the center of gravity of the wing as determined by the placement of the hang block.
BOTH THE WING AND THE TRIKE, HAVE TO BE IN CORRECT BALANCE BEFORE FLYING THE AIRCRAFT.
The reason for stating the two balance points separately, is that one can be changed to an incorrect position without changing the other. Changing either, will change the flight characteristics of the aircraft. Only when both are correct, will the aircraft fly correctly.
You need to think of the mechanics of the trike hanging from the hang bolt without the wing. The trike hangs from a single bolt and is free to swing like a pendulum fore and aft until it finds its center. The only way to change where the Trike ends up, is to move the load (weight) around in the trike, or change the position of the mast thus re-locating the hang point (hang bolt through the mast) fore and aft from its present position. This of course is done by repositioning the the mast thus moving the hang point forward or rearward. This is most often done by changing the length of the down tube.
In my book I show how I do this step by step. Please go to my Go Fund Me Page and help me with my project. The Gold Membership gives you free access to the Chapters of the book, here on Mike’s Trikes, as they are being put together. You also get hands on build videos and exact cad drawings of every part. Please consider a generous donation to let me finish this project. The gold membership is 100 dollars. It is hard to find a good set of plans for any aircraft for that price. Say nothing to the book with a step by step explanation of how I did it.