Hi All,
Bill, I think you have the right answer for all the event directors.
This would be the only fair (and easy) way to make a decision. As in
the past, if some can't identify "one" model in the air what will the
rotor "is it or isn't it" do to them. I realize that some competitors
will complain about this, but it will work the same for everyone and
will be doable by the event directors. A good example - At our
regional one heli. top prop braced itself against two right angle
sides of a ceiling box with its probe against the ceiling itself for
a while. it was technically only against the ceiling but only one
prop was turning. How would you call this? Fortunately, at that point
it was already in first place so I didn't have to make a decision.
Chris Borland - Sacramento
On Mar 31, 2011, at 7:03 AM, Bill Gowen wrote:
>
> Jeff
> First off - I don't have a dog in this hunt. I'm done with
> helicopters for this year.
>
> I understand the difficulty of making the call on whether the
> copter is flying or hung. But the easy route would have been to say
> that both rotors have to keep turning. If the rotor stops the
> flight time stops.
>
> With the FAQ that has been issued I think all of the top teams will
> be working on ways to exploit the stopped rotor scenario. And the
> worst case I can think of is that on Wednesday before the Nationals
> a rules clarification is issued banning stopped rotors. Yes, I've
> been thru a similar situation.
>
> ----- Original Message -----
> From: Jeff
> To: Indoor_Construction_at_yahoogroups.com
> Sent: Thursday, March 31, 2011 9:23 AM
> Subject: [Indoor_Construction] Re: SO Helicopter
>
>
> Not sure what you are reading into the FAQ, but timing stops when
> the rotors stop supporting the copter OR it touches the ground.
> Problem being addressed is how to determine when rotors aren't
> supporting the full weight.
>
> In practice, the judges I've observed have stopped the clock
> whenever a portion hung over something for any time, but not when
> it bumped and came free quickly. Also not when it was UNDER and not
> locked in place vertically (though frankly those cases have been rare)
>
> Problem in writing the rule is for every case I've seen or can
> think of where the copter is or isn't still supporting the weight I
> can think of a counter case with the opposite result. Thus it was
> left to the event supervisors discretion.
>
> Jeff Anderson
> Livonia, MI
>
> --- In Indoor_Construction_at_yahoogroups.com, "Bill Gowen"
> <wdgowen_at_...> wrote:
> >
> > As far as I can tell from the posted "FAQ" any flight where the
> helicopter lands on the floor at the end is legal.
> >
> > ----- Original Message -----
> > From: abcd4321
> > To: Indoor_Construction_at_yahoogroups.com
> > Sent: Wednesday, March 30, 2011 9:20 PM
> > Subject: [Indoor_Construction] Re: SO Helicopter
> >
> >
> >
> > Sorry to keep asking the same question but i am rather new at
> free flight models.
> >
> > If the helicopters top prop stops spinning but it comes down by
> itself is it legal? If not can someone explain why?
> >
> > Also what do people think the top times will be at the NSO
> Tournament?
> >
> > Thanks!
> >
> > --- In Indoor_Construction_at_yahoogroups.com, "Bill Gowen"
> <wdgowen_at_> wrote:
> > >
> > > Note to the moderator - the below is not a rules related post!
> > >
> > > Without the benefit of any actual knowledge on my part I think
> you can say that when both rotors are spinning they are getting
> equal torque from the motor and would therefore have something
> close to the same RPM. When you stop one of them the torque to the
> other one does not increase so there shouldn't be any major change
> in the RPM of that rotor. Therefore it will take something close to
> twice as long for the motor to unwind.
> > >
> > > In the process of attempting to design a helicopter myself I
> experimented with fins replacing the bottom rotor. This
> configuration wouldn't generate enough lift to fly. My GUESS is
> that the same would probably apply to most twin rotor copters. I
> think without the benefit of support by the ceiling they probably
> wouldn't stay in the air.
> > >
> > > Notice all the disclaimers in the above opinions.
> > >
> > >
> > > And part of the issue with on-line responses, if you are not
> there to see it, it could be hard to judge if held up mechanically
> or aerodynamically. Which, to me, makes all the difference in the
> world.
> > >
> > > Its also why I asked the theoretical question. Because if I
> can't explain what I think I'm seeing 30 ft over my head against
> bright lights, is my interpretation correct?
> > > - Is the longer flight time reasonably explainable from a
> purely theoretical aerodynamic sense?
> > > - If some one could point me to the relevant propellor
> equations I might be able to puzzle it out with some examples.
> > > - Seems like a simple question, but I may be oversimplifying.
> Which has lower drag?
> > > --Two propellors identical but opposite pitch props working
> together.
> > > -- or one of those propellors working by itself
> > > -- to produce the same lift (or maybe exceed the minimum lift?).
> > > - True for all operating conditions, or just some?
> > > - Because if the drag isn't lower, how can the flight be longer?
> > > - And is it a small or large effect?
> > >
> > > Thanks,
> > >
> > > Jeff Anderson
> > > Livonia, MI
> > >
> >
>
>
>
>
Received on Thu Mar 31 2011 - 13:49:38 CEST
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