Re: LPP Postal Contest Rule Clarification

From: jeffrey.hood <jhood_at_hmcon.com>
Date: Sat, 24 Mar 2007 17:33:07 -0000

> I ask for clarification of this rule as it pertains to the LPP
Postal Contest:
>
> 21.3.6. No gadgets of any kind are permitted on the model (i.e.,
variable
> pitch props, automatic incidence changing mechanisms, etc.).
>
> My question is whether a prop that is intended and designed to
flare, either
> positively or negatively, through the normal torsion of the prop
material,
> under flight loads, would be considered a "variable pitch prop" and
 therefore
> a prohibited "gadget" under this rule.

Nope... as long as there are no hinges, folding mechanisms, gears,
etc, it is okay... Those devices constitute "gadgets" to my
interpretation... Flaring via twisting the spar of the prop is an
accepted way of achieving flare of the blades... Some spar
arrangements sometimes are questioned, as in use of multiple carbon
rod elements for a more controlled flare, or as Jim Clem apparently
had at a USIC a while back, carbon fiber spars that twisted to an
upper pitch, and then stopped when they contacted each other... I
think that was disallowed by the CD at the time, but I would even be
okay with that... my read of the rules (and I guess since it is my
postal I get to make this decision... :) ) is that as long as there
are no mechanisms like the aforementioned, and the deforming of the
spar (wood or carbon fiber) is accomplished solely with forces exerted
on the prop during the normal release of energy from the motor, it
would be okay by me...

Hope this clarifies it... (and someone can correct me if they think
that my interpretation of the rules is off... :) )

>
> I ask this in consideration of parallel language in the EZB rules:
>
> 19.2.11. It is prohibited to use any scheme, device, or mechanism
which
> affects the rate of energy release from the rubber motor, except for
propeller
> blade flare or deformation.
>
> I cite this because it shows that where the intent of the rule maker
was to
> allow flaring props, it was stated in the rule. That it is not so
stated in
> the LPP rules suggests that it was not the intent of the rule maker
to allow
> flaring props.
>
> I have no preference whether flaring is or is not allowed. I can
fly under
> either interpretation. I request clarification because I don't want
 to
> violate the rules nor do I want to neglect an opportunity to
optimize my propeller.
>
> Thank you,
>
> Gary Hinze
Received on Sat Mar 24 2007 - 10:33:11 CET