In my experience, increased pitch on the bottom blade helped with stability.
There is a point that too much pitch will exceed the critical angle of
attack and you will loose lift--and stability--though.
HTH,
Kody (who had his competition today)
On Sat, Apr 9, 2011 at 10:26 PM, abcd4321 <sarathjaladi_at_yahoo.com> wrote:
>
>
> Does any one if increasing the pitch of the bottom fixed prop so that the
> motor stick/prop spin slower is a good idea.
>
> Thanks!
>
> --- In Indoor_Construction_at_yahoogroups.com, "Jeff" <janderson_at_...> wrote:
> >
> > Process is someone has to ask the question on the clarification form
> on-site, then a committee rules.
> >
> > Anyone can submit a question.
> >
> > Answers take a little longer.
> >
> > 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
> >
> > --- In Indoor_Construction_at_yahoogroups.com, William Gowen <wdgowen_at_>
> wrote:
> > >
> > > I just checked the NSO website and didn't see a clarification.
> > >
> > > 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
> > > > > >
> > > > >
> > > >
> > > >
> > > >
> > >
> >
>
>
>
Received on Sat Apr 09 2011 - 20:08:12 CEST
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:46 CET