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Spektrum DSM2 interference detector trials:
When I read that the latest version of the Spektrum AR7000 could output a datastream quantifying any failures of the transmitter to receiver 2.4GHz DMS2 link, the idea that this could be used to detect areas of particularly high noise began to take shape. Loss of signal by the receiver occurs when the signal to noise ratio becomes so small that the signal from the transmitter can no longer be discerned from noise (unwanted signals). Both the signal and noise strengths vary with distance from the source.
When the AR7000 DSM2 receiving system encounters a marginal signal to noise ratio it calls this an antenna fade (A) and switches to a second receiver/antenna combination within milliseconds. If the second receiver/antenna combination fails this is also called an antenna fade (B) and then the subsequent loss of information is called a frame (data packet) loss and if several frame losses sequentially occur then the system declares a hold. The AR7000 receiver contains an output data stream that reports the number of antenna fades for receiver A and receiver B, the total number of frame losses and the number of holds, in real time. This datastream can be inputted to a monitoring device, in this case I used an EagleTree V3 datalogger. You could also remote the datastream back to an FPV pilot/observer or a remote data dashboard.

Spektrum says that several antenna fades (50 or so per flight) and several frame losses (20 or so per flight) are normal for a typical flight and if the number of antenna fades exceeds 500 per flight then you should reconfigure the receiver locations in the plane, etc.

The plan was to attach an AR7000 with one remote receiver to the fuse of a slowstick so that there was minimal blockage from motor, esc, battery etc during flight.

Next , fly to different predetermined locations near the field using time as the locator , then after the flight,  analyze the data looking for areas of high antenna fades and frame losses.

Here are a couple of pictures of the SS fuse and a shameless plug for BlueSkyRC’s nifty new plywood stick motor mount.

SlowStick Fuse showing two part receiver and data logger.

New motor mount from BlueSkyRC

Well , like many ideas, this one didn’t pass the experimental stage. On the first flight there were zero antenna fades recorded during a 20 minute flight around Nichols park in Gilbert, AZ. I checked the system using the range check function, it was working, antenna fades and frame losses could be generated but only at a distance of several hundred feet with the range check switch on (transmitter power output greatly reduced). (flying your plane with the range check switch on is highly risky).
On a second try I actually did record two antenna fades during a 20 minute flight but they were at the very edge of my visual ability to determine the attitude of the plane.
A third flight several days later produced zero antenna fades in 15 minutes.

This idea began to resemble a solution that was looking for a problem.

I’m sure that signal blockage by large brick batteries, perhaps some carbon fiber and a large motor can occur, but for park flyers, the DSM2 link between transmitter and receiver is extremely strong and reliable. In larger planes, common sense in positioning receiver(s) is obviously required.

In this case, adding a second redundant receiver was not necessary, the primary receiver was openly exposed and did not fade within visual range.

The next time one of my planes falls from the sky, the last thing I will suspect as the cause is radio link failure due to either low signal strength or high levels of interference. DSM2 technology is indeed robust and impressive.

Modeltech’s “Blue Max”, flown by Snoopy and controlled by Al Gerben.  67 inch wingspan’
Approx. 6.5 pounds.Power is a 1000 watt Scorpion motor and the battery is a 4 cell 3500ma LIPO.  I have to say, a pleasure to watch this plane in the air.

Mansell Models Stitts Skybaby

On October 20^th, 2009, the sky was grey with scattered clouds and the adrenaline was pumping. Tom Mansell was able to maiden the ¼ scale Stitts Skybaby with a large crowd to boot.  The plane took to the sky quickly as Tom put plenty of space between the plane and the ground to get it all trimmed out.   After a few minor adjustments and taking out the rudder mixing, the plane flew really well despite It’s 44oz flight weight.   The attached video contains footage of the maiden flight and some from the next few days.  What a pleasure to watch this plane fly.

Tom based this model on RCM plans that were drawn up by Pat Trittle.  Though the dimensions and airfoil are similar to Andy Clancy’s Skybaby, there have been many changes that mostly include structural reinforcement that will support the 300 watt motor.  Tom designed the rudder to be more like the original full scale plane and added ailerons and extra ribs to support the ailerons.  The bottom wing has been greatly reinforced to support the widened landing gear.  This thing tracks very well on the ground.  Though Tom referenced the RCM plans he has created an entirely new airplane here.

Tom framed up the plane after having JTechLaser.com laser cut his parts.  He then handed it over to Steve Mueller (a dedicated scale builder) to finish up the Skybaby.  The local response to the plane has been amazing and it sure is something to see in person.

Tom is making plans to make the kit available under Mansell Models and will probably be available in the next few months on BlueSkyRC.com.

Here are some of the statistics on the finished plane:

E-Flite 480, an APC 12X6E prop, a Turnigy 40amp ESC, a 3-cell 11.1 volt 2200mah Li-poly battery, and 4 servos for the Rudder, elevator and one for each set of ailerons.

RCGroups Skybaby Thread

Click read more to see more photos.
Read more…

E-Flight Jenny flown by Eli Wagoner

Welcome to Spotlight, we will be posting photos on a weekly basis to give the viewers a look at what is happening at the fields.

Less than 20 years after the Wright brother’s first flight, Henry Woodhouse published a textbook on Aeronautic Engineering.  Excerpts from this book that relate to German WWI war planes have been reprinted and offered for sale for less than $10 at this site:

If you ‘re interested in modeling WWI aircraft, this collection contains details of construction that can be used to improve the accuracy of your models.  Other details , like the configuration of the  control linkages may not be of much modeling help but will be interesting to WWI era airplane history buffs.

The Fokker Single Seater Biplane D-7 makes a good example of the contents of this collection.   Photographs and diagrams are abundant and the specific topics covered include:  Airfoil, Wing Construction, Struts, Fuselage, Tail, Undercarriage, Engine and mounting, Radiator, Petrol and Oil Systems, Throttle control and Fabric and Dope.

The advancement in aviation in its first two decades is amazing and exemplified in the contents of this publication.

This book is well worth the reasonable price and if you have even a glancing interest in early aviation I recommend it.

Rus' Teeny Slow Stick

One of the best things about going out to the local field is seeing all the new and unique planes that come out of the local creative minds.  Just when you think just about everything has been done with the GWS Slow Stick, something totally unique shows up.   Rus Carlson, of Mesa, recently brought out to the park one of the most modified Slow Sticks I have seen to date (if you can still call it a Slow Stick).   Rus was given a very small section of the center wing of a Slow Stick by one of the other locals (thanks Ev) and he was told, “let’s see if you can use that for something”.

Using Depron and thin plywood and a little carbon fiber, Rus has built a low-wing rudder elevator trickster park flyer.  It rolls like it has ailerons, spins like a tornado and floats in like a butterfly.  We even got to see him fly it through a hula hoop the other morning.

Wing Span:   16.5″, Average chord: 10.5″

Weight:   5-5/8 oz (w/o battery)

Motor:   Turnigy 2211 (1700kv)

Battery:  Flightmax  2 cell,   500mAh,  20C,  7 minute flights

Click on the Read More to see a couple more photos.

Read more…

One thing that’s easy to see when out flying with the group is a fun-loving attitude. This week my 1st grade son brought home a monkey as part of a writing assignment. He was supposed to write about what this monkey did while he was with us over fall break. David immediately suggested that we should give him an airplane ride, so we strapped him on and off he went. Being a rookie flyer, I let David fly this round but the kids all thought it was great. We even snapped a few photos for posterity. Its great to see how much kids enjoy watching the planes – I’m sure we’ve got a few young RC pilots in the making.

When Monkeys Fly

I acquired a short kit for a Dr1 from the designer, David Payne,  at BlueSkyRC a few weeks ago and the build is about complete.
This is a 31 inch (top wing span) 1/9 Scale model of the famous tri-wing WW1 fighter. As a scale model it has the same number of wing ribs as the original and your first impression when inspecting the kit is ‘holy cow that’s a lot of ribs’.    ( phrase acquired at Joe’s BBQ)
Framing the plane is straightforward but takes some time, I found myself searching through sheets of laser cut balsa looking for individual parts.  Speaking of laser cut parts, these were excellent, having been cut by master laser cutter,  Jim Wagoner at JTechlaser.
David has a build thread on RCGroups and combining the photos online with his well drawn plans  provides the direction required to successfully complete the building of this plane.  This is not a kit for the first time builder, but with a grand sum total of 2 different short kits and a couple  full  kits of experience I was able to get the pieces glued together to complete the framing.  The cowl is located and attached with two carbon fiber eighth inch rods and two pairs of magnets.  Binding for the metal wires for the cabanes and later the landing gear was braided kevlar fishing line, saturated with thin CA.
The rudder and elevator servos are located with mini-connector adjustment access from the open cockpit and use push rods.  The aileron servos were glued to the cover plates and wind up inside the top wing with the servo arm protruding thru the plates.

OK,  so now I’ve got 4 wings, a fuselage, 4 control surfaces, a balsa/plywood cowl,  etc, and it’s time to decide on which full scale Dr1 this model is going to look like.  The decision was made,  a blue and white Dr1, registered in Germany as PH-EBF, which is a replica of Dr1  flown by LT von Raben, Jasta 7, 155/17.   Here’s the one picture I could find of that plane actually in the air, among a dozen or so ground shots including one of the plane displayed indoors in a museum in Belgium.

The Dr1 aircraft preceded color photography, so the actual colors are often disputed.  History indicates that the blue color was based on a fabric sample that was mistakenly assumed to be from LT von Raben’s Dr1 but probably came from a later Fokker DVII that replaced the Dr1.  Nevertheless, I really liked the blue and white scheme , so my plane is a model of above PH-EBF which is a replica of LT von Raben’s Dr1, which was probably red and white rather than blue and white.

Here’s the firewall and motor mount , note the carbon rods, magnets and tapers on the motor mount to give a little down and right thrust.

with Cowl attached

Looking into cockpit showing location of tail servos.

motor mount, faux motor, esc is velcroed inside top of cowl.

Aileron Servo configuration.

von Raben's white Raven, graphics by Callie.

Ready for flight.

Building this plane has been a learning experience, a lot of fun, and because of the well executed design and quality laser cutting produced a good looking scale model Dr1.  Will it fly? —  report coming up in a few days.

Link to Callie Graphics