Radar Guns/ Unlimted Speeds

[marke]

I was wondering if anybody has used a Radar Gun to See what kind of top speed the Unlimteds are turning. I know they have onboard telemetry. Would this be safe to do? Seems so. with Base balls being shot with radar guns etc, This would be on the fastest part of the couse. Also what speed was Dago Red was running if you used the previous timing system, when Dago was blowing everybody away lap times. September Fury was putting in some great speeds also. I know that top speed versus average is alot diffferent, but it would be interesting thing to bring up in discussion. Did Dago Red break 500 mph Lap Speed if you used the old timing system. When they were on a roll. I like what the Bear has done, but have always been a fan of the Stang.

Mark

[Mike51]

Re: Radar Guns/ Unlimted Speeds

What would a radar gun tell you that telemetry doesn't? And surely it would be much less accurate.

[MRussell]

Re: Radar Guns/ Unlimted Speeds

I do have one, but it only goes to 199mph.

[Mluvara]

Re: Radar Guns/ Unlimted Speeds

Good luck finding a low cost radar gun that works to those speeds...The radar signal shouldn't interfere with anything, but one would also need to be able to aim the radar gun head on, which you would have a hard time doing.

The lap speeds are relative. They are tied to a distance and then use the good old Distance = Rate x Time equation. You can go convert the old to new lap speeds. I think it is a difference of 2%. I've said it before, but if what I think is true about the timing/course system, Dago was actually doing ~520mph on the record run.

Michael

[Apteryx]

Re: Radar Guns/ Unlimted Speeds

I sold radar guns a few years back, and the early ones, didn't even go to three digits, and none of the guns in my time would indicate 200+.
Really, what would be the need?
I think a good GPS would be more accurate.
Unless your going through timing gates, speed doesn't matter any way, just as long as it's a little faster then the next guy.

[Reno_Steve]

Re: Radar Guns/ Unlimted Speeds

An accurate way of measuring speed which some of you may already have unknowingly made timings with is by the Doppler effect.

Using a tape recorder or video camera you record the sound as the aircraft flies past and later load the sound into your PC as a WAV file.

Software is available which works an osciloscope and displays the sound using a Fast Fourier transform as a frequency/time.
By comparing the change in frequency between the aircraft coming towards you against that when it is going away from you the speed can be calculated.
I have used this technique with model RC aircraft and the results have been consistent with times recorded by other means.
Go dig out your old video tapes and have a play.

[Bill@Interstell]

Re: Radar Guns/ Unlimted Speeds

Or you could note the indicated air speed and do the corrections for temperatire and pressure like they teach you in ground school.

That is if you're not too busy to look.

[Reno_Steve]

Re: Radar Guns/ Unlimted Speeds

I presumed the question was from a spectators point of view with no access to the aircraft. For normal use a GPS would probably give the best results if mounted in the plane.
Maybe we could arrange for a download from each onboard planes GPS to be available to all on a website. Might give some interesting results.

[First time Juke]

Re: Radar Guns/ Unlimted Speeds

I do have one, but it only goes to 199mph.

This is not a problem if you measure speed of the Rare Bear from a 350 mph going Lancair IV. Or is it ?

[Reno_Steve]

Re: Radar Guns/ Unlimted Speeds

To modify a radar gun to read higher speeds a divide circuit can be used.
We are having similar problems with RC gliders as these are reaching speeds of over 300mph, outside the range of most radar guns.

We should have a cheap solution soon.

http://www.rcgroups.com/forums/showthread.php?t=772890

http://www.rcgroups.com/forums/showthread.php?t=772890