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Old Dec 15, 2012, 05:00 PM
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I just wanted to let everyone know that there are quite a few fliers on youtube to have claimed to be flying over 200 mph with their edf jetsx. . . .how are we gonna proove true speed?
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Old Dec 15, 2012, 05:03 PM
Current project: Electrolyte
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True airspeed is not what this challenge is being judged on. The doppler passes will tell ground speed. If you care to know true airspeed you can install an in flight air speed indicator.
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Old Dec 15, 2012, 07:16 PM
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Doppler and radar (the two methods we're using) do measure groundspeed.

But measuring opposite direction passes in the same flight cancels out any headwind or tailwind.

If wind is cancelled out, groundspeed will match airspeed, so what we're getting is as good as airspeed.

Airspeed sensors are nice, but don't do well for this contest format because of the calibration issues and installation variables. The standalone units (not tied to a logger that can be analyzed later) are also subject to spikes that don't give a true representation of the plane's speed.

Quote:
I just wanted to let everyone know that there are quite a few fliers on youtube to have claimed to be flying over 200 mph with their edf jetsx. . . .how are we gonna proove true speed?
Pretty easy to verify if it's on video. Just doppler it.
Many of these claims come from a single time a GPS unit, airspeed sensor, or phone doppler app spat out a 247mph that could never be repeated.
They're also likely to have been a single downwind pass, so not what the plane can really do in a no-wind condition.
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Old Dec 15, 2012, 08:39 PM
Current project: Electrolyte
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Quote:
Originally Posted by murdnunoc View Post
Doppler and radar (the two methods we're using) do measure groundspeed.
According to the rules found in the first post, doppler is the definitive decision maker for speed!

Another interesting concept that was proposed by someone was the use of FPV.
Its definitely a realistic consideration worth discussing that was not possible only a few years ago. I can see why someone might go that route. Is that really fair game?
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Old Dec 15, 2012, 11:16 PM
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To me it seems very irresponsible to go FPV on something as extreme as the setups that will be run here.

A whole bunch happens really quick at 200mph on any size plane. A 70mm size plane would be downright foolish.
Add to the challenge of FPV flying the fact that we'll be trying to drive as close as possible to the camera/radar, and it increases the danger.

I haven't read the AMA safety code regarding FPV, but I'd bet a nice steak that it recommends against small planes at high speed being controlled by FPV.
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Old Dec 16, 2012, 12:41 AM
Aka: Tom Jenkins
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Palm Beach County, Fl.
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Here's my sunracer with a hat cam taped to it, turn the volume down, you'll get the drift I'm smelling if yer wanting to fly fpv at warp speed. its quite the slay ride

sunracer.wmv (3 min 55 sec)
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Old Dec 16, 2012, 12:49 AM
Lee Liddle
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Carrollton, Tx
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FPV on that!, Not me baby.LOL
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Old Dec 16, 2012, 03:13 AM
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Good God Apex your Sunracer must be doing 150+!
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Old Dec 16, 2012, 07:58 AM
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Quote:
Originally Posted by pdawg View Post
According to the rules found in the first post, doppler is the definitive decision maker for speed!
From what was discussed in the "200mph with 70mm " thread, we were going to accept both radar and doppler. It was discussed that way a few times, and it seemed like everyone was happy with both.

I'd be fine with doppler only. It's what I use myself because of the ease of verification by outside parties. But I do understand those who prefer radar, and I don't think it would cause a problem to use it, too.
Thing is, we know any video that gets posted with radar results is going to be dopplered anyway "just to check..."

What you think, Apex?
Doppler only, or radar and doppler?
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Old Dec 16, 2012, 08:16 AM
Lee Liddle
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Carrollton, Tx
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As far as Radar goes, it would still have to be accompanied by a video, and guys are going to Doppler the video.. I`m pretty sure that if the Doppler of the video doesn`t match the radar gun, that the radar gun`s accuracy would be questioned by many, especially if it was going to be at the top of the speeds posted.

So my feeling on radar is, there`s no problem using it in a video, but it`s going to have to match the Doppler, or it`s not going to be accepted. Much like using a Doppler App on a phone. It`s good for immediate feedback and can help you fine tune your flying style for best speed, but it`s still going to have to be verified by a separate Doppler analysis.
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Old Dec 16, 2012, 08:32 AM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
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Satrting my 70mm build Today

Since I`m waiting on magnet wire to rewind the motor on my 35mm Nanospot, I`ll be starting my first build on a 70mm Mini-spot. Most would not consider a 70mm a "mini", but since the original Hotspot, is about 5ft and weighs 25lbs or so, I think Minispot will work.

Aprox specs.....

Span 32"
Length 36"
Weight 4lbs
Power 3kw to 4kw

It will be basically the same as the Nanospot that has been Dopplered at 87mph on weak lipos. However, the Minispot will be......twice as big, with 4 times the wing area, 12 times the weight, and at least 24 times the power, yep, 24 times the power. So grab the popcorn boys.

I`ll be posting periodic progress reports here, but will also be doing a separate more complete build and progress thread. I`ll add a link here as soon as I get the thread going.
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Old Dec 16, 2012, 10:10 AM
Flirtin With Disaster !!
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United States, OR, Mt Angel
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Quote:
Originally Posted by ApexAero View Post
Here's my sunracer with a hat cam taped to it, turn the volume down, you'll get the drift I'm smelling if yer wanting to fly fpv at warp speed. its quite the slay ride

http://www.youtube.com/watch?v=QrpfB...tZxp-A&index=9
Nice looking RC club you have!
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Old Dec 16, 2012, 01:15 PM
Lee Liddle
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Carrollton, Tx
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Minispot 70mm takes shape

I`m taking a lunch break, thought I`d post a few pics.
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Last edited by Knife Liddle; Dec 16, 2012 at 01:21 PM.
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Old Dec 16, 2012, 04:23 PM
Aka: Tom Jenkins
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Palm Beach County, Fl.
Joined Aug 2008
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Lee, I'm guessing the motor goes under the hole in the fuse gusset? That shroud leaves a ton of room for your turkey feathers if you're running WFO then adjusting the efflux for the speed pass right?
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Old Dec 16, 2012, 04:27 PM
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Turkey??
Liking how this sounds.
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