Response #2 to SEN 97-22 - 22 Oct 1997

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News and Reports - 1997

Response #2 to 97-21 of 22 October 1997 

Re: SCAT Electronic News 22 October 1997 

At 01:13 AM 10/24/97 +0000, you wrote:
>In reply to : Mail No :005125 Oct 23 17:01:39 1997   From
inet:RWaterman@aol.c>> on Re: SCAT Electronic News  22 October 1997
>
>
>E-mail from Bob Waterman ..
>
>
>Interesting conversation with Ralph Cooney on the way back from Lost
>Hills - Livotto. After watching a relative novice - Charlie Stiles - (with an
>electronic timer) trim out an F1C during the contest, making slight timer
>adjustments to tune his flight, Ralph hypothesized that it would be an easy
>addition to add either a motion or a proximity sensor to the model so that
>when the model stopped, or got close to the ground, the chip clock in the
>timer recorded the time of the flight. A timer official on the flight line
>could plug into each plane after the flight, record the official time, and
>zero out the timer for the next official. Additionally, without much weight
>cost, a motion sensor could be added to record the stopping of the
>propeller, and that time of engine run could be recorded and retrieved
>after each flight as well. We brainstormed all of the "what if's and
>problems we could think of and I won't go into them here respecting your
>desire to stay awake, but the total idea is feasible and solves problems
>like "line of sight" and human reflexes on short motor runs.
>
>Ain't America Great,
>
>Waterman
>
>Reply from Roger Morrell
>
>Bob
>
>It's obviously a long ride back from Lost Hills to where ever you and
>Ralph hail from ! ..
>
>I like the idea and will experiment putting it in one of my timers - I
>think the most important item is the choice of 100% reliable sensor to
>detect contact with the ground. Proximity sensors are a little heavier and
>more expensive than a simple switch.
>
>On the motor run I have done some work on a recording tachometer that
>you put in the airplane and it measures rpm and altitude  .. and saves it for
>later analysis.  If my ride home was as long as your I'd be thinking how to
>change the needle setting during the climb as well.
>
>Say how about this .. not do it in the timer at all - but in a separate device
>that you strapped on the model. It only need weigh a couple of grams and
>could be supplied by the organizer to stop cheating. It can be light because
>the battery can be very small as it does not have to drive anything
>mechanical .
>
>In fact what say we try this at the Patterson Contest - I will make up some
>of these.
>
>Give me any input on the sensor for detection of end of flight ..
>
>Roger
>
>... what you other flyers think of this  ?
>
>Roger Morrell


Roger & Bob,

I like it.  Besides being more fair & accurate, it would make the contest
day much more enjoyable as we would all be relieved of timing duty and be
able to spend more time with models and friends, or resting out of the sun.

First thing that pops into my mind is accelerometers.  There are now
extremely small devices which are integrated right onto a chip.  If you
sensed acceleration in all 3 axis, I believe there would always be some
output in at least one of them while the model is flying.  So all you have
to do is have a microcontroller which starts a clock, moniters the 3
accelerations, and stops the clock when they all return to zero.

One slight problem is that a flight might get a few extra seconds as the
model may take some time to fully come to rest on the ground, or if it is
very windy the model could tumble and the system would think it is flying.
Also a challenge would be how to start the system, especially in F1A, but
I'm sure we could find a way.

Ken
Ken Bauer
Airtek Engineering
RF Circuit & System Design
This email address is being protected from spambots. You need JavaScript enabled to view it.
PHONE: 909-393-9889

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