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Posted by SoaringDude | May 26, 2014 @ 12:33 PM | 985 Views
Recently I started an RC Groups thread on the subject of windy TD/ALES contest flying and got some great feedback. The original post included an outline of windy "How to" topics. This post presents an expanded version of the original outline with the purpose of being a guide for anyone who wants to explore topics that address flying better in wind.

If you have specific topics you want to see added or expanded in this outline feel free to contribute a comment here.

Chris

Windy contest flying outline

How to use ballast
The upsides and downsides of adding ballast
When to start ballasting
Amount of ballast to use
Wind-specific TX settings
By flight mode
Consider creating separate TX "model" for windy conditions
Launches in wind
Self launching versus your timer holding your plane
Launch camber changes in wind
Dealing with gusts on launch
Winch pedal-to-the-metal versus tap-tap-tap, which should you use?
Finding lift in wind
Search strategies in high winds
Upwind versus downwind searches
Working lift in wind
Thermal versus wave techniques
Thermal turns in high winds versus surfing
How far downwind should you follow a thermal?
Landings in wind
Changes to landing pattern
Changes to use of flaps
.....What happens if you use too much flap?
Ballast and damage on harder "off axis" landings

Posted by SoaringDude | May 09, 2014 @ 12:17 PM | 2,338 Views
This is a follow-up to my blog post "Protective fuses for your servos" immediately preceding this one. While the micro fuses in that post would do a good job protecting your plane from a potentially catastrophic servo short circuit, using a resettable "polyfuse" is even better since it never needs to be replaced if it ever trips. I owe Mike Wilson the credit for suggesting this alternative.

The resettable fuse part number: TE Connectivity p/n RUEF110 1.1A 30V, Mouser p/n 650-RUEF110, $0.32/ea in qty 10. These devices are low cost and small (14x7mm) "radial" package devices that look like capacitors and should be soldered directly into your harness in front of each servo you want to isolate for short circuit faults (described later in this post).

How they work

If you're electronically curious you can read how these resettable fuses work here. The basic idea: current that exceeds the rated trip current causes the polyfuse to heat up and increase its resistance thereby reducing the current to safe levels until either the short circuit terminates or until the fuse is reset via a power cycle.

Bench tests

To test this device I used a Hyperion 2S LiFe 1450mAh battery, a 68 ohm 1 watt resistor to simulate a 100mA average servo load, and a 1ohm current shunt that allowed a digital storage oscilloscope to display the current flowing through the servo load during short circuit conditions. Two types of tests were performed: a continuous...Continue Reading
Posted by SoaringDude | Apr 29, 2014 @ 11:12 PM | 1,888 Views
May 9 2014 update: I just added a new blog post "Resettable fuse isolation for servos" that describes an even better servo fuse solution than the one described in this post.

A recent RCG thread related how a plane that was being bench tested all of a sudden experienced a servo short circuit failure that quickly melted a servo connector, harness wires, and even some of the plane's wing skin. Had this happened in the air the plane would have lost control as soon as the battery was drained, which would not take long with a short circuit in progress.

One of the posts by Tuan (RCG: fnnwizard) suggested a fuse for each servo as a protection mechanism so I did a bit of research and found a nice submicro fuse that can be directly soldered into your harness for each servo you want to protect. These are Littlefuse sealed micro slow blow fuses, $1.11/ea in qty 10 and in stock at mouser.com.

1.5A fuse: Mouser p/n 576-047301.5MRT1L, Littlefuse p/n 047301.5MRT1L
2.0A fuse: Mouser p/n 576-0473002.MRT1L, Littlefuse p/n 0473002.MRT1L
2.5A fuse: Mouser p/n 576-047302.5MRT1L, Littlefuse p/n 047302.5MRT1L
Manufacturer datasheet
Construction: molded epoxy + axial solder leads. Dimensions: 3.4mm x 7.1mm (small!)

Comparison of times/currents to fuse blow:
1.5A fuse: 2.7A in 100sec, 3.1A in 10sec, 4A in 1sec, 5A in 0.5sec
2.0A fuse: 3.5A in 100sec, 4.3A in 10sec, 6A in 1sec, 7A in 0.5sec
2.5A fuse: 4.2A in 100sec, 5.0A in 10sec, 7A in 1sec, 8A in 0.5sec


Note...Continue Reading
Posted by SoaringDude | Sep 19, 2013 @ 06:20 PM | 2,269 Views
Wanted to give a heads up about a new product that many RC flying clubs may find helpful. It's called the Wind Field Display which provides an outdoor large LED display of current wind conditions. It shows Current, Average, and Peak wind speeds, wind direction in degrees, and it has a wind alarm feature. This allows you to set a wind speed that, when reached, will cause an alarm relay to turn on any external audio or visual attention-getting device. More info here.

Chris B.
Posted by SoaringDude | Feb 06, 2013 @ 12:14 PM | 2,851 Views
A few days ago I started an open Club Safety thread in our soaring club's RCG forum. The purpose is to allow a free exchange of ideas and recommendations on field and flying safety. I'm very impressed with the contributions. Other clubs with RCG forums might want to consider doing the same thing.

Chris B.
Posted by SoaringDude | Jan 21, 2013 @ 10:13 AM | 2,711 Views
On January 1, 2013 it was reported on RC Groups that a spectator had been killed at an RC soaring slope site in Germany. After a healthy exchange of posts on RCG it became apparent the issues of RC flying club safety preparation and insurance awareness were in need of help.

From this discussion I decided it would be a worthwhile effort to launch a project that would create a well-researched outline for an RC Flying Club Safety Plan. This work is done and available on this project website to RC clubs to use as a guide.

It's gratifying to see some clubs have already taken the outline and plan to use it to develop their own safety plan. Any questions or feedback don't hesitate to ask.

Chris B.
Posted by SoaringDude | Dec 22, 2012 @ 12:14 AM | 3,258 Views
While the number of RC flying fields that are close to a NEXRAD weather radar site are small, I know from RCG searches that there are at least several others that have suspected radar interference problems.

I just posted an article on my soaring club's RCG forum here that explores how the NEXRAD radar works and when/why RC interference might result.

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January 6, 2013 Update:

Several days after my original NEXRAD post on our club forum I received a nice email from club member Jonathan Heritage offering some great feedback. In it he suggested that using the Friis Transmission Equation we might get a better idea of how closely we could fly to the NEXRAD radar ball before our 2.4gHz receivers get swamped out from the high power radar pulses. After running some quick numbers Jonathan's well-reasoned conclusion was that our planes should be safe as long as we don't get too close. Since we aren't seeing very many control issues in that quadrant of the sky he's no doubt right.

I decided that it would be helpful to build a spreadsheet that implemented the Friis equation and then apply it at various points on our flying field. The basic idea was to calculate how much NEXRAD power would be received at a plane's 2.4gHz receiver antenna terminals compared to our RC transmitter signals.

So here's the net conclusion from this analysis. At the worst possible field location point "I" (i.e. farthest from where pilots stand with their...Continue Reading
Posted by SoaringDude | Mar 26, 2012 @ 08:21 PM | 3,794 Views
We've been developing a new "pulse load test" that can test voltage regulators with high current pulses from an actual LiFe 2S pack. The goal was to simulate high current demands from digital servos under high flight loads and see how the regulators handle it. This capability was just announced in the Voltage Regulator thread.

All the tests that have been posted so far on RC Info Share now have pulse test data. There is also a new Pulse Test Results Compilation document on the tests page that graphically compares all regulators tested so far.

These tests were developed with much technical help and suggestions from Mike Wilson.

Chris B.
Posted by SoaringDude | Feb 26, 2012 @ 09:58 AM | 4,060 Views
I just posted an article here in my club's RCG forum (SVSS forum) about using voltage regulators and voltage reducers to keep LiFe battery pack voltages under manufacturer's limits for many popular servos.

Comments/feedback welcome.

Chris B.
Posted by SoaringDude | Feb 22, 2012 @ 09:02 AM | 4,391 Views
At our local flying field yesterday afternoon trying out an 8oz ballast bar in 10-12mph winds. Impressions:
With ballast: Flys really well w/ 8oz bar, makes final approach more predictable in this kind of wind. One negative: it noticeably slows down response in thermal turns, makes it feel a little "laggy." However penetration is better and wins out overall.
Without ballast: You can definitely catch smaller thermals and bumps. You can land the plane okay w/o ballast in 10-12mph winds but you have to keep your speed up to buck the wind on final. I tended to land long on time until later in the afternoon. This plane responds very well to surfing into the wind with 2-4mm camber: it floats amazingly well in wind and allows you to stretch a flight out much better than my X3.8 (AUW 79oz).
Posted by SoaringDude | Feb 13, 2012 @ 10:54 PM | 5,729 Views
After flying 1 years with an Xplorer 3.8 that was built by Claude Turner, I decided to build one myself. Got the model at Visalia in Oct 2011 from Soaring USA (SUSA) for a great price but didn't actually start the build until December. This was my first ever molded plane build.

There are other excellent Xplorer build logs like this one from Tony Kilwein. So I decided to do this log with the idea that I might be able to help other beginner molded plane builders. I'm not describing every single step I took but rather I'm highlighting those areas that cost me more time given my lack of experience. I'm including many pics of the linkage for all control surfaces so it's easier to replicate on your first build.

First, I do owe a big THANK YOU to several people:
1. Ed Stewart, who has built many Xplorers. SUSA gave me his number when I asked detailed build questions and Ed had great answers. If you decide to get your Xplorer built by someone, I heartily recommend Ed. He knows his stuff and his fees are more than reasonable.

2. Scott Meader, our local build expert who also has built a ton of Xplorers. Scott was very willing to share some extremely valuable tricks and suggestions. Could not have done it without him.

3. Many others, include WebbSolution/Dave, Kilwein, Bob @ SUSA, Target, Tom Watson, Tuan, and others. Much of what I am relating in this build log I learned from them.

One more point: I'm a long time advocate of honest feedback when I do projects...Continue Reading
Posted by SoaringDude | Feb 13, 2012 @ 09:08 AM | 4,277 Views
I recently posted two more reports on RC Info Share's Voltage Regulator Tests page. These new reports show the results of performance tests for the Greentronic RegSlim linear regulator and the Castle 10A CC BEC switching regulator. Both products passed the tests although there are some important and significant differences about how they each do their job.

One note on the test plan itself: we are continually evolving the test methods to better test the regulators for performance in RC plane applications i.e. using the latest battery packs and more accurately simulating the loads they see in flight.

More tests coming...

Chris B.
Posted by SoaringDude | Feb 08, 2012 @ 09:47 AM | 4,268 Views
I just posted a new YouTube video showing how I approach launch and landing practice for thermal duration (TD) contests. I did it to answer questions from several friends but thought it was worth posting here. This video shows the last 4 landings during a 2-hour practice session at our club's field. Chris B.

Posted by SoaringDude | Jan 20, 2012 @ 10:39 AM | 4,441 Views
A new page has been added to the RC Info Share site. It is the Voltage Regulator Tests page which is where we will post testing results for voltage regulators that are usable (or not based on the tests) in RC soaring applications.

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I just posted a test report on the Novak 5A Universal BEC #5465. This is a very compact linear regulator that works really well in RC soaring applications. With small reasonably-priced regulators like this there's no excuse for shortening the life of your non-HV servos by running them at too-high voltages.

Chris B.
Posted by SoaringDude | Dec 16, 2011 @ 10:00 PM | 4,670 Views
Have finally decided to start up a basic website RC Info Share with the purpose of sharing RC soaring product comparisons. It will also be used to post product testing results.

The genesis of this site was driven by several RCG threads in the F3X forum on the topic of MKS Servos and voltage regulators for soaring use. The ongoing problem with using LiFePO4 ("LiFe") batteries with servos seems to have gotten worse specifically with MKS. i.e. they seem slightly more sensitive to voltages above 6v than other brands. Too bad since they are the tightest servos around with amazing centering performance.

So RC Info Share was launched to list specs for RC voltage regulators that can be used to reduce servo supply voltages in planes. Also created a "Voltage Reducer" section to show diode voltage reducer solutions which have a number of benefits over the typical regulators (including a board I designed and am producing for the soaring community).

I have the ability to add other website authors to this site so other areas can be opened up as needed.

Chris B.
Posted by SoaringDude | Mar 03, 2011 @ 11:54 AM | 19,914 Views
For the last 2 months I have been shooting aerial footage using a GoPro HD Hero camera. Awesome camera. As part of the process I have been experimenting with how to best process the video to remove shaking from the video clips as the camera itself does not have an image stabilization function.

I just posted a side-by-side video comparison of two different methods of stabilizing video footage: Method 1 is using the built-in Stabilize Media option (Tools | Video menu) found in the Sony Vegas Studio HD Platinum 10.0 software. This is an earlier version of the proDAD Mercalli video stabilizer that has received good reviews. Method 2 is using the VirtualDub video editing program and the companion Deshaker filter plug-in, both of which are available for free.


I included embedded comments in the video and which method I like better. If and when I decide to shell out $200 for the proDAD Mercalli plug-in I will also post a comparison of that. For now, though, I'm happy with

Stabilization settings I used: (Note: I first convert all GoPro MP4 video files using the HuffYUV lossless codec in VirtualDub and saved as an AVI file before deshaking)

Vegas Movie Studio HD Platinum 10.0:
Type: General footage, Intensive Analysis
Rolling shutter correction: checked

VirtualDub Deshaker filter:
Pass 1: Square pixels, Progressive scan, Camcorder has a rolling shutter: Amount: 82%
Vid output: Motion vectors, Block size: 30 pixels, Scale: Full, Use pixels: All, Color mode: RGB
Detect rotation: checked, Detect zoom: checked
Remember discarded areas to next frame: checked
Pass 2: Same destination properties as source: checked, Resampling: Bicubic,
Edge compensation: Adaptive+ fixed (no borders)
Extra zoom factor: 1
Motion smoothness: all 4 values are 1000
Max correction limits: Horiz, Vert, & Zoom: 15, Rotation: 5

Comments welcome.

Chris B.
Posted by SoaringDude | Jan 18, 2011 @ 01:12 PM | 7,106 Views
To all those asking, here's how I mounted the HD Hero camera on my non-powered gliders. Many HD Hero owners use the clear plastic case that comes with the camera but I decided to go for best video quality (it's an HD camera after all) and minimum drag by mounting the camera "naked." I got the basic idea from a post on RC Groups.

Basically, the mount is a piece of 1/16" aluminum that bolts to the top of the wing using longer wing bolts. I have different pairs of wing bolt holes drilled so the same bracket works with both my gliders. The camera is secured using zip ties. Holes are drilled allowing the camera to be attached facing front, back, left, and right: you get to pick one direction per flight .

Several important details: first, drill the wing bolt bracket holes so you center the camera weight over your plane's CG. This will minimize trimming changes. FWIW, even with the CG unchanged I still needed lots of up trim with the camera on board. Next, you want to protect your glider from the metal mount with foam. Pic 4 shows how I used thicker foam in the center and thinner foam on the mount "extensions." Pic 3 shows the cut channels in the foam to allow for the zip ties. Next, you will need to use longer wing bolts. On both my gliders it took an extra 10mm of bolt length to do the trick.

Finally, but of critical importance, it is HIGHLY advised that you use short wing bolt spacers between the camera bracket and the wing bolt holes in the...Continue Reading
Posted by SoaringDude | Dec 06, 2010 @ 02:21 PM | 6,320 Views
Since the debate is still raging (long RCG thread) regarding whether you need to use a voltage reduction circuit or not when using LiFePO4 2S battery packs, I decided several days ago to call Airtronics and get their official answer to which specific internal components in their servos would be overstressed if you were to use a direct-connected LiFe 2S battery pack. Just got a callback from Jack Albrecht in Airtronics support who reported the following verbally:

"According to the word directly from Sanwa, through Mike Greenshields, ALL Airtronics equipment (receivers and servos) are approved for use when direct connected to all packs from 4-cell AA through A123 / LiFe 2S battery packs."

When I asked for a clarification on how far back (i.e. previous servo purchases) you can go and still have their blessing, he said any servo with a "blue connector." When I also asked about the fact that LiFe packs do put out 7.0v briefly off the charger, he said that surface charge did not last long and was not a concern to them.

So I can't speak for other servo manufacturers (yet) but Airtronics is giving a thumbs up for direct-connected LiFe 2S packs.

Chris B.
Posted by SoaringDude | Nov 15, 2010 @ 10:49 PM | 7,697 Views
In response to the excellent thread on running with LiFePO4 battery packs, I have received many requests for details on how to hook up the parts for the voltage-reducing circuit when you want to connect a LiFePO4 2S battery pack to a plane that uses servos and/or a receiver that is rated for 6v or less.

The PDF attachment is a schematic and notes that follow-up the initial connection description from Flo in Munich on the subject.

If you plan to add this circuit to your plane, be sure to follow all instructions and especially the thorough ground test described in the schematic notes.

If you have feedback or suggestions I'll be happy to update this post and the attachment. Just to be clear about this, I offer this information without assuming any liability for the ultimate outcome of your particular implementation of this circuit, okay?

Regards,

Chris B.