An consideration with regard to half motors. because force = mass *
acceleration, a partial motor will not tell you whether your model will take
the increased torque on a full motor. Because the rubber has greater
distance to pull from. If there are any slight abnormalities on partial
test, it is necessary to readjust before you do a full motor. Thinking that
partial motors would tell me something about torque load cause me to
demolish a model in the Salt Mine.
Nick Ray
On 11/30/06, Bill Gowen <b.gowen_at_earthlink.net> wrote:
>
> Okay guys - here's the fly in the ointment. When you are doing your
> testing/adjusting/optimizing you are setting up the model for the conditions
> that are in effect on THAT DAY and THAT TIME. When you fly in slightly
> different conditions your trim settings and power requirements might need to
> be slightly different. If you're flying in Johnson City conditions with a
> storm front moving through and lots of humidity your model may barely fly
> with your optimized settings.
>
> I'm not saying that there's anything wrong with the approach. It's just
> that you have to be prepared to make changes as conditions require.
> Sometimes events are won or lost depending on flyer's ability to adjust to
> prevailing conditions. You probably don't even need to ask me how I know
> this!
>
> ----- Original Message -----
> From: torqueburner
> To: Indoor_Construction_at_yahoogroups.com<Indoor_Construction%40yahoogroups.com>
> Sent: Thursday, November 30, 2006 9:24 AM
> Subject: [Indoor_Construction] Re:prop pitch
>
> --- In Indoor_Construction_at_yahoogroups.com<Indoor_Construction%40yahoogroups.com>,
> "Bill Gowen" <b.gowen_at_...> wrote:
> >
> . . .Optimal pitch is the one that gives you the highest flight time. . .
> >
> . . .Adjust the cruise first. Get the best combination of prop pitch and
> model trim for the
> cruise. Then go for the ceiling height with launch torque adjustments. . .
>
> Brant, our experience with SO planes agrees with what Bill has suggested.
> Last year my
> students modified an Ikara prop so that had an adjstable hub that allowed
> for changes in
> pitch. They set the pitch, then made several flights each with a variety
> of rubber sizes that
> differed by 0.005". They found that there was a range of pitches that
> seemed to give them
> pretty comparable times if matched up with the appropriate rubber size.
>
> If the pitch was higher than this range, flight times dropped - it was
> tough to get it all the
> way up to the top. If the pitch was too low, the plane climbed so well
> that they had to back
> way off on the turns, and the times were lower as well.
>
> One interesting thing we discovered at last year's state competition: the
> students had
> found what they considered an optimal combination of pitch and rubber by
> flying half
> motors in our gym. But at the competition, the plane just wouldn't climb
> out, even when
> launched at a much higher torque than they had used in practice. When we
> got home, we
> measured the pitch of the prop they had been using - it had changed to a
> higher pitch! So
> I guess when they heated/twisted it to repitch it, it relaxed over time
> back toward the
> original pitch.
>
> Has anyone else seen this problem with repitched plastic props? If so, any
> suggestions as
> how to prevent it?
>
> Dave Drummer
> Kutztown Sr. High School
>
> [Non-text portions of this message have been removed]
>
>
>
[Non-text portions of this message have been removed]
Received on Thu Nov 30 2006 - 11:27:30 CET
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:44 CET