My understanding is that in the 2 state finals I'm familiar with the top
rotor locked into either a ceiling tile or a light fixture.
The copter then stayed there until the torque dropped enough for it to fall
free.
The kid I was helping had his copter hang the top rotor on a practice
flight. It took over 10 minutes for the bottom rotor to stop. In his case
the copter didn't fall so it wouldn't have been a legal flight (I guess).
So I don't think we're talking about an aerodynamic phenomena. The copter is
being supported by the ceiling - not by the thrust from the bottom rotor.
On Wed, Mar 30, 2011 at 3:34 PM, Jeff <janderson_at_twmi.rr.com> wrote:
>
>
> So we don't get to far on AMA rules, reminder, they only inform SO rules
> writers and SOME event supervisors. The only binding rules for SO are the
> ones published by SO and have in the past specifically contradicted AMA
> practice, eg torque burners.
>
> Side question on the theory behind this. How does it work?? For one rotor
> to hold the same weight as two it has to spin faster, increasing drag that
> rotors drag. Is this increase less than the loss of drag from stopping the
> other rotor? If not, how is efficiency (flight time) increased? If it is,
> then I understand the result.
>
> Thanks,
>
> Jeff Anderson
> Livonia, MI
>
>
> --- In Indoor_Construction_at_yahoogroups.com, Benjamin Saks <bensaks_at_...>
> wrote:
> >
> > I remember back in my youth of chasing the Junior AMA Helicopter record
> that
> > there were old designs which used this practice to kill the top rotor
> spin
> > and get longer flight times. I could be wrong but I think that they made
> > flights like this grounds for disqualification.
> >
> > In order for this to work well, you need to "drill" the top rotor pylon
> into
> > the ceiling. It works in the soft drop ceiling tile best, but I could not
> > imagine anywhere else. Otherwise you would have to get lucky and lock in
> the
> > rotor into a girder or something, assuming it would release when the
> power
> > decreased enough.
> >
> > On Wed, Mar 30, 2011 at 3:17 PM, Jeff <janderson_at_...> wrote:
> >
> > >
> > >
> > > Tom has it right, this is NOT the place for official clarifications,
> those
> > > are only posted on the NSO website so they are available to all.
> > >
> > > Also, I'm only one voice in these decisions, several others contributed
> to
> > > the final, published rules and they all get a voice in coming up with
> the
> > > official answers.
> > >
> > > I can however quote the relevant portion of rule, 3.k "...Time Aloft
> ...
> > > stops when ... the rotors no longer support the weight of the
> helicopter..."
> > >
> > > While the answer seems clear to me from that, I wrote it, thus the need
> for
> > > an official clarification. Especially since I'm supervising Robot Arm
> this
> > > year, not Helicopters, at the national contest.
> > >
> > >
> > > --- In Indoor_Construction_at_yahoogroups.com, "Thomas" <parkreation_at_>
> > > wrote:
> > > >
> > > > Not to dodge this issue, but this needs to be addressed first through
> SO
> > > Clarifications before a statement may be published. Even still, I would
> > > rather yield to Jeff A. on this anyway as this event is his creation.
> let me
> > > see what else I can uncover...
> > > >
> > > > Regards,
> > > > Tom Sanders
> > > > SO National Supr (Wright Stuff)
> > > >
> > > > --- In Indoor_Construction_at_yahoogroups.com, "Bill Gowen" <wdgowen_at_>
> > > wrote:
> > > > >
> > > > > I'd be interested in hearing from Tom and Jeff on this subject.
> > > > >
> > > > > ----- Original Message -----
> > > > > From: abcd4321
> > > > > To: Indoor_Construction_at_yahoogroups.com
> > > > > Sent: Tuesday, March 29, 2011 6:16 PM
> > > > > Subject: [Indoor_Construction] SO Helicopter
> > > > >
> > > > >
> > > > >
> > > > > Hi, my team recently won the NJ state Science Olympiad Tournament
> so we
> > > are going to nationals. We had a 2:12 helicopter flight wHich got us
> second
> > > place. I recently found out that it is possible to get much higher
> times if
> > > the top (free) rotor stops spinning once the copter reaches the ceiling
> and
> > > starts to spin again once the copter starts to come down. However
> Locking
> > > the rotor does not work as the motor stick still needs to spin.
> Essentially
> > > he rotor must get stuck to the ceiling under the lift generated solely
> by
> > > the lower rotor. We tried to just use tape which worked until it got
> stuck
> > > to tightly.
> > > > >
> > > > > I was hoping you guys could help out.
> > > > >
> > > > > Thanks,
> > > > > Sarath Jaladi
> > > > >
> > > >
> > >
> > >
> > >
> >
> >
> >
> > --
> > BEN SAKS
> > www.bensaks.com
> >
>
>
>
Received on Wed Mar 30 2011 - 12:43:10 CEST
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:46 CET