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Anyone Have Issues Flying Elev-8 On Hot/Humid Days? — Parallax Forums

Anyone Have Issues Flying Elev-8 On Hot/Humid Days?

Out here in Texas, the temps have gotten up around mid 90's with humidity in the 50 - 60% range. I have on occasion flown under these conditions and have had a sudden pitch over and crash with no apparent cause that I could determine. I have noticed that after flying around 8 - 10 minutes the motors are hot to the touch. The last time I crashed, I had swapped out a battery for a fresh one.

I have since let my aircraft cool down after a flight - will fly another aircraft. And then change batteries and fly. So far, I've had no mishaps. I know that with heat/humidity, density altitude increases and the aircraft has to work harder to stay in the air. But I'm wondering if anyone else has had problems with heat and humidity.

BTW, my Tarot 4002 motors also feel hot after a flight. But if I fly under cooler conditions, the motors (both types) feel fine after landing.

Comments

  • I have to ask, is this with the APM or the Parallax FC?
  • High humidity and high temperatures can certainly affect the density of the air but I fly my Elev-8 here in Idaho at 4,500 ft altitude without trouble. I'm betting the problems are heat related rather than air density related.

    I gather this is your impression as well.

    I personally don't go outside when it's hot (transplanted hearts don't deal with temperature extremes well) so I haven't flown my Elev-8 when it's been hot.
  • I've flow the ELEV-8 v3 at a density altitude of 8300 ft without any trouble. Can you provide some specs on the platform you are flying (ELEV-8 v2 or v3, takeoff weight, and any modifications you have made)? I know you've done quite a bit of customizing to some of your platforms, just not sure which one this is. Thanks!
  • I have flown all three of my aircraft under these conditions. All three are using APM 2.6 F.C's. The Elev-8 that crashed is the lightest of the three as it has no extras (video equipment, gimbal, etc.), at 3.8 lbs. It is using the stock motors for the V2 Elev-8.

    The other Elev-8, with the Tarot motors, gimbal, GoPro Hero4, telemetry, video transmitter & 4S lipo weighs in at 5.6 lbs.

    The Tarot hexcopter is the heavyweight at 6.8 lbs. It too, has a gimbal, GoPro Hero4, video transmitter and 4S lipo.

    Motors on all three feel hot to the touch when I fly in 90+ degree weather, but all seem to fly okay. On cooler days (70+), the motors feel fine after a flight.

    I only mentioned the density altitude thing in that I know that the props get less bite in the air ans therefore I have to fly at higher throttle settings than otherwise.

    Like I've said, lately, all three have been flying okay, but I've been careful not to hover in place for very long and after a flight, I given the motors time to cool down before attempting a 2nd flight.

    On a side note, I have to say, flying the Elev-8 is a pleasure!
  • Not sure how much any of this will be helpful since you probably know most of it, but anyways...
    You're spot on that the motors will have to spin faster to create equivalent thrust due to the lower density, so It doesn't surprise me much that the motors might get warm in those conditions, which is fine. But if they get above 150 F or so (hot enough to quickly cause a burn), then the are being overworked.
    The pitch over could be cause by a motor failing in flight, but if the motors weren't overheating, I think it is more likely an issue with an ESC going bad or the flight controller. I won't be much help with the flight controller, but as far as the ESC is concerned, most failures are catastrophic and irreversible, so if it's working once everything cools off, it probably wasn't the cause of failure during the flight.
  • Thanks Kyle for your response! I did suffer previous crashes where I suspected a bad ESC and changing out ESC's seemed to fix the problem On my lightest Elev-8, the one without all the video stuff, I actually swapped out the stock 30A ESC's from Parallax with 40A, thinking one or more were bad. But as I swapping out the last one, I discovered I had a bad motor! I completed the swap out anyway, and I'm happy with them.

    I don't think the motors got that hot, but they were indeed hot to touch.

    I don't know if the APM, or any other F.C. for that matter is subject to heat sensitivity in the 90 degree range. I've decided to just fly sparingly on hot days, if at all. Also, I do occasional static tests of the motors to satisfy myself that they are all running okay. When it comes time to replace the stock motors on my Elev-8, I may move up to the Tarot motors and strap on a 4S lipo - it should really fly! It will also make my logistics easier by dealing with the same motor on all three copters...
  • If the motors ran again later without swapping them it's very unlikely to be a motor issue. ESCs occasionally have thermal overload protection, but that's pretty rare - if yours are inexpensive that won't likely be it. It could be expansion of a board causing a solder joint to fail. When it cooled back down it would likely reconnect, so it would appear a lot like a thermal shutdown.

    Kyle and Ken have both flown in sub-zero (even snowing) as well as +80 degrees with no resulting issues that I know of.
  • Thanks Jason - Motors run fine afterwards and I have confidence in the ESC's. I've triple checked all of my solder joints, but hadn't considered a possible joint on the F.C. board - I might open it up and take a look-see...
  • kwinnkwinn Posts: 8,697
    GlassKNees wrote: »
    Thanks Jason - Motors run fine afterwards and I have confidence in the ESC's. I've triple checked all of my solder joints, but hadn't considered a possible joint on the F.C. board - I might open it up and take a look-see...

    One cause of intermittent problems I have come across in the past has been the feedthru. Very difficult to localize but if that is the cause of your problem soldering a wire to both sides of the board should take care of it.
  • Will be going out for a test flight later today. I did notice some vibration in #3 motor during a static test. Examination revealed that one of the mounting screws worked itself loose and fell out. I replaced it and put a dab of clear nail polish on it to hold it in place. I had forgotten to do this when I last replaced the motor. I find that a dab of clear nail polish will hold the screw in place but is easy to remove if I have to replace a motor....
  • PublisonPublison Posts: 12,366
    edited 2016-09-10 15:19
    Locktite Blue is always recommended for high vibration mountings.

    http://www.loctiteproducts.com/p/t_lkr_blue/overview/Loctite-Threadlocker-Blue-242.htm

    Good luck on the test flight!

  • Well, it flew fine yesterday, that is until it clipped a tree. I was going to do a video shoot and programmed a waypoint mission so the autopilot would fly the aircraft while I concentrated on the camera. Unfortunately, I set the altitude just a tad too low for a tree that was in the flight path.

    I uploaded the same mission on both Elev-8 quads - flew the one without the camera first as a sort of dry run to make sure I had it lined up for the video shoot. I broke two props when it got hung up in the tree but there appears to be no other damage. I will have to check it out today.

    I did go back home, altered the altitude,made a couple of other minor adjustments and uploaded the revised mission to the aircraft and flew it. I was monitoring the live video feed so I could take evasive action in case I got too close to a tree, but it wasn't necessary - the flight went well.
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