Originally Posted by
John_M_
Ahh yes I understand... Is it possible the model has a nose down stance when the model is static on the ground, it would have a negative wing incidence ... that would aggravate the issue, as the models ground speed increases so would the downward pressure on the nose gear... can you raise the nose stance so the wing has a positive incidence sitting on the ground?
***EDIT***
Never mind I just saw your photos of it sitting on the table, it looks like it has a good positive stance on the ground.
That was actually the issue: Static, it stands 3,5 degrees positive. When rolling, the nose dips with increasiong speed until fully compressed at 0,9 degree
negative: The nose (measured at the tip) dips almost 2,5" from full extended to full compressed nosegear. Those O-rings start interfering with spring stiffness at +2,6 degrees, so I have good hope the nose dipping will be limited to that.
Remember that geometry I was talking about? The first 3/4" of nose dip allready compresses the spring halfway through its travel. the remaining 1-3/4"of nose dip is spread over the remaining half of the spring travel, That is that change in leverage, and the spring being linear means that the resulting returnforce is not...
The issue is compounded by main gears with rather stiff springs and a rather progressive linkage.
To be honest, I think these legs are designed more for looks than for practicality.