On 20.8.2011 16:59, Brett Sanborn wrote:
> On the Treger hubs that Ben bought last time we were in Serbia, the
> spring dimensions seemed to be consistent with what was on the plan, .2
> mm wire with 3.5 coils. However we don’t actually know if the ones that
> Ivan sells are the ones that he uses, right?
>
I took a pic of a Treger hub that Geoffrey (from UK) bought, it seems to
be also 3 turns spring.
Talking of which (the springs), I discussed 'em with the Brits, and
learned an interesting concept about "hard" and "soft" springs. Looks
like the one that I have been using, with 7 turns, is in the "soft
category", resulting in an abtrupt change of pitch when it eventually
happens. And with a harder spring I would have the prop staying longer
"on the spring", making the change in the altitude while on the spring
more variable. I guess the next step is to measure the motor torque
curve while unwinding, measure the VP action, and try to figure the
torque -> pitch & RPM -> output power pattern of the flight, then think
if a different pattern of changes would be more efficient.
I have a feeling that I have just opened a new door slightly, and have
taken a brief peek into the room.... Wonder what I'll find there :-)
-Tapio-
- application/x-ygp-stripped attachment: stored
Received on Thu Aug 25 2011 - 22:28:55 CEST