WHAT CAUSED THE MIRACLE FLIGHT?

              

By Frank Sutton

Alex received his Motion RC AL37 jet airliner as a Christmas gift. Of course, he was thrilled. As many of you already know, Alex plans to be a jet airliner pilot and is already flying actual sailplanes as a member of Cypress Soaring (https://www.cypresssoaring.org/) in addition to flying R/C planes with Silent Electric Flyers San Diego (SEFSD). He is preparing to solo in a Cypress Soaring sailplane later this year.

              Alex assembled his brand new Motion RC AL37 jet airliner on Christmas Day, and he installed a known good SPECTRUM AR620 6-Channel Sport Receiver from another plane. Unfortunately, he soon discovered that the lights and retractable landing gear worked but the twin jet engines would not start. Alex spent many hours unsuccessfully troubleshooting the engine problem for several days. All of the receivers he tried would work fine and start the engines on other aircraft, but none of his receivers would start the the new AL37 jet engines.

              We reached out to Motion RC’s Technical Support for assistance and eventually attempted to troubleshoot the engine problem via E-mail and text messages with Motion RC’s Technician “Andrew”. Unfortunately, all the troubleshooting by Andrew and Alex remained unsuccessful – the jet’s engines would simply make a beeping tone and not start.

              We were planning to ship the engines and electronics back to Motion RC for troubleshooting when Andrew told us he lives not too far away in the Lake Elsinore area, and he invited us to bring the plane, or at least the electronics and jet engines, to his home to troubleshoot himself. We gratefully accepted his generous offer and met Andrew at his home in Lake Elsinore on Saturday afternoon, 04JAN2020, after Alex’s sailplane flight at Hemet Airport with a Cypress Soaring Instructor.

              Andrew conducted the same troubleshooting procedures that Alex had repeatedly performed with the same negative results. Andrew then brought out a brand new Admiral RX600SP 6-Channel DSMX Compatible Receiver with Stability Plus Gyro available from the Motion RC Website and connected it to the AL37. We were soon very happy to hear the jet engines come to life for the very first time!

              For still unknown reasons, the Spectrum AR620 Receivers were not compatible with the AL37. Andrew recommended we use an Admiral RX600SP Receiver (the same type that he used to get the engines working). We saw for ourselves the Admiral Receiver was obviously working for the AL37 while the Spectrum AR620 Receiver did not, so we ordered two of them from the Motion RC Website after returning home that evening. The brand new Admiral RX600SP Receivers arrived on Friday 10JAN20, just in time to install and fly the AL37 with a new Admiral Receiver the next day!

              Alex successfully flew the AL37’s “Maiden” flight on Saturday, 11JAN20, at SEFSD Field. All went perfectly well and the AL37 flew beautifully! Not long afterwards, Alex was ready to fly the second flight with another fully-charged battery. We did not know at takeoff that the AL37 was about to fly off into history, and we would forever remember this second flight as “The Miracle Flight”!

              The Miracle Flight began routinely, the AL37 jet airliner took off right to left and circled back around again, but after heading towards the Sea World rollercoasters a second time while starting to turn right, Alex calmly but loudly reported something that I very much dreaded to hear – he’d lost connection with the aircraft! OH NO!

              The AL37 jet airliner seemed to break away from a right-hand turn and went into a left-hand turn, then it rolled over upside-down while going into a Kamikazi-like maneuver heading straight down at a very high rate of speed! We lost sight of the jet airliner as it went down below the bush line, and we thought the beautiful AL37 jet airliner had just crashed fast and hard leaving nothing but a hole in the ground full of foam, broken parts, and our broken hearts!

              Much to our amazement, however, the big beautiful AL37 jet airliner miraculously reappeared again a little farther to the right, rising from beneath the bush line and it was slowly soaring upwards, again gaining altitude! From our perspective at the runway, the AL37 seemed to be riding right up the rails of the new rollercoaster as it was heading back into the sky! WOW! It didn’t crash! UNBELIEVABLE!              

              I was instantly suffering from a severe case of “Shock and Awe”! I was momentarily dazed and confused! I was trying to comprehend the miracle I’d just witnessed when I instinctively and loudly ordered Alex to land as quickly as possible. All I could think of was how much I didn’t want to hear Alex call out another loss of connectivity while the jet airlner was still in the air!

              Alex and I later discoverd most of the SEFSD Pilots at the runway that day witnessed the Miracle Flight’s near disaster and recovery, and they also momentarily believed the jet had crashed before it climbed back into the sky!

              That day I was experimenting with our GoPro camera and recorded both the Maiden and Miracle Flights on video, and part of the Miracle Flight was also recorded on our van’s dash camera. If you haven’t yet seen it, the “Maiden and Miracle Flights” video is posted on the SEFSD Website in the “SEFSD General Flying & New Jets – JAN20” gallery. It is the second “photo” from the left in the top row. The first “photo” is the “Hawaiian Airlines” video of Jovi’s beautiful Hawaiian Airlines AL37. Here is the direct link to the Miracle Flight video:

  https://sefsd.smugmug.com/SEFSD-General-Flying/i-qczjCr7/A

              Alex landed the AL37 successfully. With the help of several SEFSD Pilots, the investigation into what caused the near catastrophy began immediately. The Admiral RX600SP Receiver was not blinking. Battery levels for both the Spectrum DX8 8-Channel Transmitter and the onboard 6S-cell battery powering the AL37 were both still outstanding. It was not obvious exactly what happened, so we grounded the AL37 until we could figure out what caused the second flight to become the Miracle Flight.

              Alex had flown several times with other planes with no anomalies before flying the AL37 that morning using the Spectrum DX8 8-Channel Transmitter, and he successfully flew those planes again with the same transmitter after the AL37’s Miracle Flight. So, we quickly suspected the loss of connectivity may be due to a faulty receiver and we vowed not to use that receiver again in another plane.

              We asked Jovi, the Hawaiian Airlines AL37 Pilot, what type of receiver did he use? Jovi had been flying his AL37 for a few weeks before Alex flew his for the first time that day, and Jovi reported that he had not experienced any problems with his AL37 using a brand new Spectrum AR8010T 8-Channel Air Integrated Telemetry Receiver. Jovi very highly recommended we switch receivers (again!). This Spectrum 8-Channel receiver has dual antennas which Alex and I thought was very smart because it gave the AL37 a better chance of receiving the transmitter’s signal, and it also had a few other upgraded features that neither the Spectrum AR620 nor the Admiral RX600SP enjoyed. Alex and I figured too, if it worked well for Jovi’s AL37, then it should work well for ours, so we bought and installed a Spectrum AR8010T Receiver for our AL37.

              After the Electroglide on Saturday, 18JAN20, Alex successfully flew the AL37 with the new AR8010T Receiver four times. Later that same day, I finally fulfilled a promise I’d made to Motion RC’s Technician “Andrew” and submitted an outstanding review on the Motion RC Website with three photos of the AL37 included . Of course, I mentioned the “Miracle Flight” and to Motion RC’s credit, my review was posted just as I’d written it.

              The new Spectrum AR8010T performed superbly, and we thought the AL37 was finally configured properly for safe flights! It wasn’t long before we discovered, however, that our AL37 was still in danger of a catastrophic connectivity loss!

              On 31JAN2020, Scott Wallace, a Motion RC customer, saw our review of the AL37 on the Motion RC Website. In the review I’d mentioned Alex and I are members of SEFSD.  Mr. Wallace visited the SEFSD Website and obtained the E-mail addrss of our club President, Tony Blackhurst, and he sent an E-mail to Tony requesting it be forward to Alex and I to warn us of what he suspected was the problem that caused the loss of connectivity on the “Miracle Flight”.  Mr. Wallace advised that our AL37 remained at high risk for a disaster despite installing the upgraded Spectrum Receiver! Mr. Wallace stated in his 30JAN2020 E-mail:

     “I saw Frank’s review of the Freewing AL37 and his near disaster when the receiver acted up. I researched with a HAM (Amateur) radio operator my crashes with a Freewing F-4. He said that high current Electronic Speed Controls (ESC’s) are known for generating common mode RF (Radio Frequency) interference. He suggested I install clip-on RF chokes as close to the ESC as possible on both the input and output side of the ESC(s). I did this and have not had any loss of TX/RX handshake since. I bought the kit which has multiple sizes and have flown hundreds of successful flights since putting these on all my EDF jets. Frank’s AL37 will act up again. He needs to get these installed.”

              Mr. Wallace voluntarily made the effort to contact and warn us of this problem, and we certainly appreciated it! He also provided a URL link for the RF Chokes available on Amazon:

 https://www.amazon.com/dp/B00V4MMIBW/ref=cm_sw_r_oth_api_i_GOgnEb78YV0SS

               I replied to Mr. Wallace (and Tony too!), thanked him for his assistance, and promised that Alex and I would spread the knowledge with all the SEFSD Pilots.

              The next day I sent an E-mail to Motion RC’s Technician, Andrew, and asked for his opinion about these “RF Chokes”. Andrew replied the same day stating:     

     “We include these types of magnetic chokes on many of our ESC’s as the BEC on the AL37. With the AL37 having so much “juice” running through it with so many functions it could be possible that some interference could be more present with this model vs others. I would say its not a bad idea at all to add some. I believe the saying goes: “An ounce of prevention is worth a pound of cure”. I’ve also added a capacitor to my setup to always provide clean voltage to my system.”

               Andrew also provided a URL link for the capacitor advertised on the Motion RC Website:

  https://www.motionrc.com/products/hobbyeagle-16v-ez-plug-capacitor

              Motion RC describes the capacitor’s function: “…Provides cheap insurance as a way to avoid electronic surges and brownouts”.

              On 01FEB2020, I replied to Andrew’s E-mail thanking him for the additional information and told him Alex and I would be sharing this information with the SEFSD Pilots, including Jovi who was flying an AL37 himself! I told Andrew that we’d grounded our own AL37 until we got this problem figured out. I also assured Andrew that Alex and I are still big fans of Motion RC and loved the AL37, and we would be watching to see what his company comes out with next!

              On Sunday, 02FEB2020, Alex and I visited Kearny Mesa’s Discount Hobby Warehouse to see if they had an RF Choke, or a Capacitor, or something that would help reduce the chances of another near-disaster with the AL37. Fortunately for us, our friend and fellow SEFSD Member, Scott Charity, was working that day so we spoke with him about the problem. He had not yet seen the video of the near-disaster, but when Alex and I started explaining what had happened, he finished our story for us – except he didn’t know our AL37 narrowly avoided crashing! Scott was confident he knew what more likely than not caused the out of control Kamikazi nose dive! Of course, Alex and I are not R/C electronic engineers and we were eager to hear another possible solution to the connectivity problem!

              Scott explained he was not at all surprised by what happened, and highly recommended we change the AL37’s power configuration to one of two methods, those being:

 1) Use a second (smaller) battery to control the flaps, elevator, rudder, numerous lights, and retractable landing gear in addition to the large battery required to power the twin jet engines.

 2) Use the single large battery to power everything, but add a Battery Eliminator Circuit (BEC) Switching Voltage Regulator.

               Scott further recommended a BEC made by a company named “Castle”. He advised a BEC would significantly reduce the chances of a momentary electronic surge or brownout, and that was more likely than not the actual cause of the connectivity loss experienced during the “Miracle Flight”. This was all new to Alex and I!

              Luckily for us, Scott had one Castle BEC2.0 left in stock so we opened it up and read the specifications manual. After talking more with Scott about our options, Alex and I decided to add the Castle BEC2.0 to the AL37 as relatively inexpensive insurance against another momentary connectivity loss. We considered the “RF Chokes” and “Capacitor” additions too, but it appeared to us that these weren’t required if a technologically superior BEC was installed. We also liked the idea that with the BEC, a secondary battery was not required to be flown onboard the AL37 to operate everything (except the two jet engines).

              On 03FEB2020 I sent an E-mail to Steven Belknap (SEFSD Editor) and several of the SEFSD Officers, including Brad Bender, informing them of these new developments. I also told them I wanted to write and submit this article to help inform other SEFSD Pilots that may want to move up to larger, more complicated aircraft and may be as unaware as Alex and I were of the optional electronic safeguards for flying these larger aircraft. Alex and I would absolutely hate to hear of an AL37 or similar complex plane going down hard because of a momentary loss of connectivity that possibly could have been prevented!

              Brad replied via E-mail on 04FEB2020 stating that he also used Castle BEC’s in most of his medium planes. Just FYI, Alex and I believe Brad’s “medium” planes are much larger than most because some of his largest planes are neary as big as a compact car! He explained for his very largest aircraft, he uses the two-(or more)-battery system because those planes have the power and lift to carry additional batteries. Brad went on to confirm in a plane with many servos, retracts, and lights, reducing the voltage from a 6S-cell battery could lead to a system brown out if a lot of things happen at once (and added that Jovi flies his aircraft more conservatively than Alex flies!).

              On Saturday, 08FEB2020, Alex once again successfully flew the Motion RC AL37 four times with the Castle Battery Elminator Circuit (BEC2.0) Switching Voltage Regulator onboard as well as the Spectrum AR8010T 8-Channel Air Integrated Telemetry Receiver. In fact, Jovi flew his AL37 together with Alex’s AL37, simultaneously in the air for the first time ever! Those two big jet airliners flying together looked very impressive, and a lot of fun!

              We also talked more with Jovi, Brad, and Scott that morning about the modifications to our AL37. We learned a few new things too including Jovi’s AL37 is set up slightly differently than Alex’s; Jovi has installed a separate gyro in his AL37, and both jet airliners seemed to be flying with no problems.

              If you’re interested, here’s Castle’s Website:

               http://home.castlecreations.com/becs

               And here’s a related article I found on Flite Test’s Website discussing BEC’s:

               https://www.flitetest.com/articles/what-is-a-battery-eliminator-circuit

                Alex and I are still learning about R/C aircraft electronics, and we probably will always be learning something new too! When the large 6S-cell batteries arrived for Alex’s AL37, we thought they were bad – they had no voltage and wouldn’t charge! We showed the suspected bad batteries to Brad one Saturday morning and he gave us our first large battery lesson – we had to connect the two dangling wires to complete the circuit for the battery cells to operate! Well, that explains it! Ha! We couldn’t figure out what those two extra wires were used for. We learned the batteries are “deactivated” when shipped by not connecting those two wires, so thanks again Brad!

              This past weekend we met with several more SEFSD Pilots about this and discovered many of them have either BEC’s or a second battery installed in their larger, more powerful planes. Thank you too, everyone, for your assistance and support; we sincerely appreciate it! Alex and I know we’re very fortunate to have discovered Silent Electric Flyers San Diego, become members, and made such good friends with so many Pilots. None of us in our family can remember what we used to do on so many weekends before flying with SEFSD!

              Thank you, SEFSD Pilots!

 V/R,

  Frank and Alex Sutton