Reforming Tail-spring Bearhawk 4

[Techman2512]

I have the flat "leaf" style spring on my Bearhawk 4. What are the negatives(concerns) to having the tail-spring reformed to add an addition inch or so(<2") increasing vision over the cowl a bit? or lengthening it a bit and reforming?
See attached pic for current.

 

[jaredyates]

I think you need more arch than pictured, to give yourself a more favorable king pin angle and mitigate shimmy. Your current spring is flatter than it's intended design, so there isn't any drawback to getting it back to conformity.

Talking about lengthening the spring sounds like a redesign/structural question. It's probably not ideal to give it more leverage against the fuselage and its mounting points. This whole area was designed as a system and it gets some hard usage.

 

[Techman2512]

I think you need more arch than pictured, to give yourself a more favorable king pin angle and mitigate shimmy. Your current spring is flatter than it's intended design, so there isn't any drawback to getting it back to conformity.

Talking about lengthening the spring sounds like a redesign/structural question. It's probably not ideal to give it more leverage against the fuselage and its mounting points. This whole area was designed as a system and it gets some hard usage.

So I should have a shop with a press give me a bit more arch/pitch than I currently have? 300 hours on plane. Is this just from normal tail first landings flattening the pitch? Should I just replace the leafs as old ones are stressed? Thanks

 

[jaredyates]

You can try bending them cold, but the ideal path would be to heat treat them back to soft, bend them, and then heat treat them back to springy. I was in your shoes at about the same number of hours and just obtained new springs. I guess back in the day just about every town had a spring shop that was set up to do this for truck springs, but in modern times perhaps less so.