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speed recording - 12/18/2007 12:07:33 AM   
Zman39



Posts: 467
Joined: 1/27/2005
From: Central, FL, USA
Status: offline 		Hey all,

I am putting together a composite electric speed plane and need to know what is a good way to record maximum speed. I saw one device but it requires drilling holes in wing for air tubes. I rather not drill holes in this beautiful plane. I have heard some do it with handheld GPS units which are accurate but not sure how small they come and probably wont be an abundance of room inside sleek fuse. Any ideas?

Thanks

Z
       Post #: 1

RE: speed recording - 12/18/2007 4:22:49 AM   
Mike Connor



Posts: 1384
Joined: 1/10/2002
From: Tulsa, OK, USA
Status: offline 		I have read here on RCU about people using a GPS unit in their aircraft to record speed but do not remember the details. You might try a search for more details. Other then that you could use Doppler, radar or stop watches to get speed.

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http://www.mikesrc.us/

(in reply to Zman39)
       Post #: 2

RE: speed recording - 12/18/2007 10:30:34 AM   
Zimodile


 

Posts: 8
Joined: 10/2/2006
From: Ibstock, UNITED KINGDOM
Status: offline 		As far as I am aware (although I may not be fully aware, so set me straight if I'm not!) the refresh speed on GPS is not high enough to get a good speed reading at the speed/ distance equation that we would typically fly at. Interested in this problem too!

Z

(in reply to Mike Connor)
       Post #: 3

RE: speed recording - 12/18/2007 10:33:03 AM   
Zman39



Posts: 467
Joined: 1/27/2005
From: Central, FL, USA
Status: offline 		I did read there are now small watches, not to pricey, that have gps and will record highest speed but havent found them in a search.

(in reply to Zimodile)
       Post #: 4

RE: speed recording - 12/18/2007 4:15:35 PM   
phjoker



Posts: 362
Joined: 9/20/2005
From: Vernon, NJ, USA
Status: offline 		the gps is an iffy.. I had put a small Garmen gps in my GP minnow w/jett90lx. One one run I was full throttle high dives and a lot of hard banking the gps read 256mph. Then i did another run with no hard banking and some smaller dives that registered 163mph. Next run NO dives NO banking just a lot of straight and level it read 142mph all of these are MAX speed. It is hard to say but we think somehow the hard banking was throwing off the gps, and since it is measuring max speed a high enough dive will give you the 163mph.At 256 for a prop plane I know somethihng very very very bad would have happened(wings folding and massive flutter) LOL
That is my experience with the gps
Pete

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RE: speed recording - 12/18/2007 4:24:41 PM   
Zman39



Posts: 467
Joined: 1/27/2005
From: Central, FL, USA
Status: offline 		good to know, sounds like that might not be the answer. i wonder who sells cheap radar guns <G>


Z

(in reply to phjoker)
       Post #: 6

RE: speed recording - 12/18/2007 10:05:44 PM   
tom3097


 

Posts: 13
Joined: 5/17/2005
From: Bloomfield, NJ, USA
Status: offline 		I had the same results as phjoker.I bought a Garmen fitness gps that we could use at the field in q500 and deltas.It seemed accurate a couple of times.But we got a lot of 250 and up readings.A few of us in our club are looking into chipping in on a radar gun.Unfortunately from what I've read anything that is going to be accurate isn't cheap.

(in reply to Zman39)
       Post #: 7

RE: speed recording - 12/19/2007 5:27:44 AM   
Troy-RCU



Posts: 503
Joined: 1/18/2002
From: Oceanside, CA, USA
Status: offline 		What airframe are you building? You will find most cheap radar guns will not detect the smaller planes. The 'How Fast' device is probably the best and easiest device you can use and it's really small. It's also accurate. You don't have to drill holes in your wing... you could conceivably tape the tubes on temporarily.

A past article I showed on here about it on a really small (24" span) pylon plane.

http://www.rcuniverse.com/forum/m_6331929/anchors_6331929/mpage_1/key_fast%252Cdevice/anchor/tm.htm#6331929


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Can you feel that Buddy, HUH, HUH, HUH!!!??
I Have EXORSIZED the electrons, this plane is clear.

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RE: speed recording - 12/19/2007 2:21:14 PM   
colbourne



Posts: 39
Joined: 11/2/2006
From: Canberra, AUSTRALIA
Status: offline 		Has anyone tried modifying this so that it transmits down to the ground the speed and can allow several passes with the speed being known each time.
Maybe a voice synthesizer on a computer would be the ideal and it could also record the data and show on the screen.

(in reply to Troy-RCU)
       Post #: 9

RE: speed recording - 12/19/2007 4:24:32 PM   
The Internet Killer


 

Posts: 222
Joined: 8/21/2005
From: Ferndale, WA, USA
Status: offline 		Don't forget the guy holding the radar gun gets "Danger Pay".

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       Post #: 10

RE: speed recording - 12/21/2007 2:44:37 AM   
colbourne



Posts: 39
Joined: 11/2/2006
From: Canberra, AUSTRALIA
Status: offline 		Does the doppler speed method work on electric aircraft ? I tried it with a gas turbine and found there were just too many frequencies to be able to pick the correct ones to compare. With gliders I have heard of people using an electric speaker to make a steady tone.
So much for silent flight

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       Post #: 11

RE: speed recording - 12/21/2007 4:35:50 AM   
Mike Connor



Posts: 1384
Joined: 1/10/2002
From: Tulsa, OK, USA
Status: offline
quote:

ORIGINAL: colbourne

Does the doppler speed method work on electric aircraft ?

Yes, If they have a prop.


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Mike
http://www.mikesrc.us/

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RE: speed recording - 12/21/2007 1:15:39 PM   
Bob R2



Posts: 513
Joined: 6/20/2004
From: , TX, USA
Status: offline 		FWIW, I've used a small Garmin with success, but you have to do a couple of things. First, go into the programming and set the sampling interval to the minimum - I believe it is one second. Second, fly large race track laps. If you fly vertical maneuvers, you get crazy speed readings. Apparently the vertical resolution isn't sufficient to accurately calculate speed in the vertical. The "how fast" device is smaller and pretty cool, but with the gps you don't have to poke holes in your plane.

(in reply to phjoker)
       Post #: 13

RE: speed recording - 12/23/2007 6:28:38 AM   
Troy-RCU



Posts: 503
Joined: 1/18/2002
From: Oceanside, CA, USA
Status: offline 		Someone figured it out for the How Fast Device. Simple, easy, effective. No poking holes in your plane.

http://www.rcgroups.com/forums/showthread.php?t=789142

< Message edited by Troy-RCU -- 12/23/2007 6:29:10 AM >


_____________________________

Can you feel that Buddy, HUH, HUH, HUH!!!??
I Have EXORSIZED the electrons, this plane is clear.

(in reply to Bob R2)
       Post #: 14

RE: speed recording - 12/23/2007 6:50:25 AM   
TheTick


 

Posts: 333
Joined: 8/17/2004
From: , CA, USA
Status: offline 		I have the prospeed radar gun and it works great but it misses alot of passes when you get around 200+mph. I got it refurbished for around $450. I've never come across a less expensive gun that can consistently clock fast small planes.

(in reply to Troy-RCU)
       Post #: 15

RE: speed recording - 12/23/2007 1:23:08 PM   
Springer



Posts: 38
Joined: 11/6/2007
From: Ringwood, NJ, USA
Status: offline
quote:

ORIGINAL: Bob R2

FWIW, I've used a small Garmin with success, but you have to do a couple of things. ........


Can I get model numbers?

(in reply to Bob R2)
       Post #: 16

RE: speed recording - 12/23/2007 5:42:01 PM