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Oct 26, 2017, 04:53 PM
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Measuring Flight Speed without a Radar Gun


As I my interest in fast-mover type planes has grown lately, I've wanted to measure airplane speed. I know a radar gun is an obvious answer, but there are issues with positioning, finding a willing helper, flying the plane at the gun (and helper) etc. Pitot tube sensors are an option as well and for a very accurate measure, I may try something like that soon.

Thanks to RCG and a little bit of research, I found a reasonable and cheap [free] alternative using a sound recording and doppler analysis software. I put a video together demonstrating the process start to finish.

Have fun...

How Fast Does it Fly? How-to Measure RC Plane Speed without a Radar Gun [tech] (11 min 49 sec)
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Oct 27, 2017, 01:50 AM
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I have been doing it for few years now and I also made a post in my blog last july publishing formula with temperature only and temperature and humidity corrective factors.
Oct 27, 2017, 02:45 PM
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You forgot to supply the WAVEosSCOPE software which actually is doing most of the work that I used to do manually, although it does not consider humidity factor, which, I must admit, is not really influencing much the result. I supply it herebelow. For the audio you could use format factory software that could extract audio from video in interested trances or divide audio file and save them directly in wav format.
Last edited by eagle60; Oct 27, 2017 at 02:50 PM.
Nov 01, 2017, 02:24 AM
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If you are interested in fast planes I could suggest you the old 1/2A class which is not too expensive. You could use my modified GLH II wings (my post of june) stright or swept eventually covered with fiberglass ( my post of july). For the fusolage you can choose from any plan that can be found here :
https://www.rcgroups.com/forums/show...RCG-Build-Logs
regardind power system depend on which speed level you want to be :
2826 2200kv 2s and 7x6 for 140/150 kmh 3s and 7x5 for 180/190 kmh
2836 2200kv 3s and 6x5 for 200/210 kmh 4s and 5x5 for 230/240 kmh
(anyway pls check absorptions to be within the given motor limit)
for higher speeds pls check https://www.rcgroups.com/forums/member.php?u=292421 for ideas.
Last edited by eagle60; Nov 01, 2017 at 02:31 AM.
Nov 09, 2017, 01:11 AM
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Wow, full circle, lol, I had the GLH about 3+ decades ago, and now I just found waveosscope and started using it tonight and still learning.

What speed would you get for this file?

EDIT: link to web
http://www.sprut.de/electronic/soft/scope.htm
Last edited by --Oz--; Nov 09, 2017 at 02:17 AM.
Nov 14, 2017, 02:14 PM
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Assuming the temperature was 20 C (it does influence the result) the speed was between 260 and 270 Kmh. It is not easy to read the graphic as noise is short and slightly dirt. Which motor is it ? If it is the RCX 2206-2400 V2 on how many cells were you running it?
Last edited by eagle60; Nov 14, 2017 at 02:23 PM.
Nov 24, 2017, 06:19 PM
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Quote:
Originally Posted by eagle60
Assuming the temperature was 20 C (it does influence the result) the speed was between 260 and 270 Kmh. It is not easy to read the graphic as noise is short and slightly dirt. Which motor is it ? If it is the RCX 2206-2400 V2 on how many cells were you running it?
Sorry late reply, 5S on 2206-2400 v3 KK5050 RS30A V2, BF3.1.7, Revolt 32K. It was a normal SoCal day, 70F.
Nov 25, 2017, 03:06 AM
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so it was about 21 C, not much a difference, it is well within the system accuracy
Mar 25, 2018, 01:20 AM
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Could you try to get a speed from this video? The later passes are quicker as the battery heats up (but it also seems to be closer to the camera for a better doppler differance), check pass at 49 seconds. tia
267kph | movr5r2 f80 2500kv 5x5 apc prop 32a kiss esc kiss fc v2 6s1300 95c (1 min 16 sec)


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