Seen top blades stop twice in competition this year by two different schools. Our local team has a top blade that stops at ceiling every time. In my opinion if it lands on floor and doesn't stay on ceiling after the bottom blades stop turning for certain amount of time the flight counts. Of course, the later "certain amount of time" should be clarified with standard time of perhaps ten seconds.
Mark
To: Indoor_Construction_at_yahoogroups.com
From: candjborland_at_surewest.net
Date: Thu, 31 Mar 2011 13:49:42 -0700
Subject: Re: [Indoor_Construction] Re: SO Helicopter
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 - 15:29:33 CEST
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