Re: Tailspring replacements

Peter Harris <peterjfharris@...>


With help from John Tenhave we analysed my broken tail spring after I landed
backwards following an encounter with the fence. The kit tail spring was
VERY poorly made with much excess resin. John designed a tubular glass
spring which Sam and I have been using successfully for the past couple of
years. It is lighter, stronger and more flexible than the original spring.
Unfortunately my spring maker is now asking AUD140 per part ie it is time
consuming tedious work that does not suit his shop.

I am sure John would release the recipe if you want to make your own but you
would need to make a slightly tapered mandrel and wrap the part and oven
cure it.

Alternatively there are manufacturers of glass fishing rods that would
possibly take on the job but volume is so small.



From: Q-LIST@... [mailto:Q-LIST@...] On Behalf Of
Mike Perry
Sent: Tuesday, 25 March 2008 2:49 AM
To: Q-LIST@...
Subject: [Q-LIST] Tailspring replacements

I'm re-reading the old newsletters. It's obvious there were many
tailspring (TS) breaks in the early days. I have questions about why the
TS broke and about replacement choices. I also need to replace my TS --
probably start on the tail cone work in about 2 months. Questions:

1) Did the QAC tailsprings break because of bad design or bad
production? That is, would a properly constructed 5/8 inch glass rod be
strong enough? Would making it longer help? (more length to dissipate
shock loads?)

2) Has anyone tried making their own TS?

3) What do experienced flyers recommend for replacement? I am aware of
spring steel (Patillo) and cut-down Dragonfly (Farnum) tailsprings. Are
there other options?

4) Is their a current source for a Dragonfly TS? I thought Aircraft
Spruce took over D-fly sales, but I don't see the D-fly in the current

Mike Perry

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