| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 1252.1 | RADAR | KAY::FISHER | Stop and smell the balsa. | Tue Oct 09 1990 12:09 | 15 |
| > One topic that I recall nothing on at all is that of measuring the
> speed of the models in the air. How about some thoughts here on
> measuring the speed of models from the actual model or between two
> points on the ground. I guess one could have a peak hold device in
> ones plane. Any ideas ?
Say an add in one of our magazines the other day for hand held radar
detectors - looks like they start around $300.
Bye --+--
Kay R. Fisher |
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| 1252.2 | Doppler module... | GALVIA::ECULLEN | It will never fly, Wright ! | Tue Oct 09 1990 13:00 | 23 |
| Radar sounds good !
I recall there being a doppler radar module available in one
of the electronic mags ($70) - drain was about 100 mA so plane operation
is possible. Then it it all depends on the height of the plane
when it passes over the module to get the speed.
I saw in a recent documentary on a group of US MIT guys who were
trying to fly, by human power alone, from Crete to Santorini, (~78 miles)
in Greece. Apart from the actual program - which was very interesting
(fancy composites -> 60lbs plane) - they had a small prop driving the
speedo electronics etc - maybe a miniature version would be possible.
Then calibration would be fun......officer, yes,... I was, ...,....Hhmmmm,
calibrating my, errrr,... ehhhh speed indicator,.....
YES THAT WILL BE A $50 ON THE SPOT !!!
!I would be interested in something really cheap and located in the plane.
Eric();
|
| 1252.3 | Use a Radar Gun | SELL3::MARRONE | | Tue Oct 09 1990 13:45 | 16 |
| It's very simple. Call the local police and invite them to your field
and ask them to bring their portable radar gun. They'll be happy to
measure the ground speed for you as your bird whizzes down the field,
but be careful, don't speed too fast or else you might get a speeding
ticket ;-)
Kidding aside, while this may not be exactly what this note had in
mind, we did have this exact experience at our Merrimack NH field a few
months ago. Seems one of the local cops stopped by to watch us flying
because he has an interest in model aviation, and one of the club
menbers asked him if he could use his radar gun to measure the speed of
our planes. Sure enough, he gladly obliged, and we spent about half an
hour doing speed runs. It was fun. I think we also got some good
press with the local police since they now know us better.
-Joe
|
| 1252.4 | | WRASSE::FRIEDRICHS | Kamikaze Eindecker pilot | Tue Oct 09 1990 13:52 | 8 |
| Yup, the local police are very good in Merrimack...
They clocked my SS-40 with its old K&B .60 doing a mere 98mph! Not bad
for a sport plane...
cheers,
jeff
|
| 1252.5 | Condor R/C has Airspeed indicators | ROCK::MINER | Dan Miner, DTN:225-4015, HLO2-3/D11 | Tue Oct 09 1990 14:42 | 17 |
| Condor R/C Specialities (or whatever their name is now) from
California sells little devices that you put in your plane and it
transmits a signal to the ground. On the ground, you have a little
hand held receiver that reads the AIRSPEED of your plane.
See note 1012.3 for more details.
_____
| \
| \ Silent POWER!
_ ___________ _________ | Happy Landings!
| \ | | | | |
|--------|- SANYO + ]-| ASTRO |--| - Dan Miner
|_/ |___________| |_________| |
| / | " The Earth needs more OZONE,
| / not Caster Oil!! "
|_____/
|
| 1252.6 | numbers for the curious | BRAT::RYDER | perpetually the bewildered beginner | Thu Oct 11 1990 06:17 | 12 |
| Just to see what numbers you might expect to measure, here are some
extractions from earlier notes:
Casey's MiG-3 at 105mph
Shailesh Patel ... Baker Jug .... 105-mph
Dan Parsons' MB-5 ... just over 120 mph
the Violett Sport Shark ... over 160 mph
Alton who is glad they make planes like Gentle Ladies for us slow types
|
| 1252.7 | Whow, that fast ? | GENRAL::KNOERLE | | Thu Oct 11 1990 16:50 | 6 |
| I wonder how fast my KNIFE-edge will fly with this healthy WEBRA 61 Long
Stoke in front, swinging a 11 x 10 at 13,000 rpm at the ground and
beeing a (besides the non retractable landing gear) overall clean plane !
Bernd
|
| 1252.8 | simple answer is pitch_in_inches x kilo_rpm | ABACUS::RYDER | perpetually the bewildered beginner | Sun Nov 18 1990 00:13 | 10 |
| >> I wonder how fast my KNIFE-edge will fly with this healthy WEBRA 61 Long
>> Stoke in front, swinging a 11 x 10 at 13,000 rpm at the ground and
To a first approximation, if the prop were moving in gelatin,
10 x 13000 / 1056 = 123 mph
In practice, I understand, the engine might spin faster once the plane
is moving, and that can result in a higher speed. In note 65.13 John
Chadd describes this as "unloading the prop".
|
| 1252.9 | polaroid rangefinder | POBOX::KAPLOW | Set the WAYBACK machine for 1982 | Thu Dec 27 1990 12:47 | 8 |
| re: .2
Several of the folks who built Dedealus are old friends of mine. I
know they had some fancy electronics, but on the actual flight
most of them failed. The altimeter was rather simple: an
ultrasonic rangfinder from Polaroid, available in an experimenters
kit. Unfortunately it is good only to about 100 feet, but then HPA
fly pretty low.
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