Today, the lower right prop vacuumed a small stone - I heard a small mini-hit sound, and my climb leveled out in spite of being at full power. Went up about 20’ and decided to land. Placed my OpenPPG on the sand and suprise!
Yep, sorry you had trouble. I have to be very careful at the beach too and do a good prop check before I put it in the car.
Ouch! You have spare propellers? Seems a good idea.
All repaired and good to go. And made a few improvements along the way.
I extended the battery holder ledge to support part of the weight - part because the packs have to tilt away from their own weight during the emergency release - there must be an off balance scenario taking place - the wight of the pack disconnects the plugs automatically due the the 26lbs weight heading downward.
Nice. My setup keeps the cables clear of the props well enough for normal operation but I didn’t think of a prop breaking. Might be nice to have some minimal shielding just between the props and the batts. Hmmmm…
2 busted props and motor detached!
My 1st flight with X4. Take off went well then around 50ft heard a crack and decided to land. I am still not sure of the exact cause… any ideas anyone?
I will try to post the video. I am guilty of hooking one side of the netting incorrectly but this would not seem to account for the problem. On the other side, the prop has obviously hit the netting at some point. I thought I had tensioned reasonably but maybe it needs to be even tighter somehow. But could a netting impact cause so much damage?? The video I think shows the right lower prop went 1st. Maybe part of this prop hit the left prop and caused that to be so imbalanced that it shook itself off the mounting?? or possibly sand was the problem as with others on this post. Any theories appreciated. I am using 6S batteries and 22x12 props with batch 4. I am also using a maytech MTS2009AS mosfet switch which seems to work very well. I love the X4 and hope to get it fixed asap. Apart from the prop bust I had a very easy take off and much prefer to a ICE.
That is heartbreaking. I’ve been there, breaking props in taller grass (always the bottom two). Almost became routine now.
Paul and Zach has access to the engine mount. The repair will go faster than you think and you’ll be up in the air soon. Hang in there.
Been there…done that! It was probably the net on the left side…and cascaded from there. All in all, I think you are lucky, and it could have been worse.
Mine happened on my Batch 3 when my throttle cable was going bad. On launch, the two motors on the right side decided to stop, and it twisted me to the ground pretty hard after about 5 steps. One of the lower props contacted the metal frame, a piece of that prop contacted another, and a piece of that prop went through my wing.
I’m glad I had a 3d printer, wing patch, extra aluminum spacers and SS socket head bolts to help with the repairs. …then I had to build a new cable. I had to order silicone wire from Amazon…maybe some of the SS nuts and bolts too and extra cage segments from Paul. Also, I had to design a new cage adapter so I didn’t have to replace the arms and connectors!
You’ll recover nicely!
Bill
Thanks bill. That’s a lot of fixing you had to do. I am thinking I might need a new motor also. I can see a tiny dent in the rim & it’s stiff to turn by hand. It looks difficult to stretch the netting really tight. I might try a cable tie onto the motor arm with each flight. Has anyone else had netting slackness issues?
You should talk to Paul about your motor. I consulted him on mine, and they turned out to be ok. Mine had a different feel and sound from the other two when I would spin them by hand, but that was two years ago, and they are still working fine.
I tighten my net with a couple strips of 3/4" Velcro before each flight…also use some fuzzy adhesive Velcro to keep the carbon from rubbing the net and Paracord.
Great tips. Thanks. I think I will copy what you are doing.
Andy,
My “fixes” may not be the best…every situation is different…but these have worked for me so far. Good luck!
Bill
You might also put a ty-wrap around each ESC and the motor arm since the mounting ears on them seem to be very weak, especially if you over tighten the screws. One narrow enough to fit between the ESC fins.
I used 1 1/2" industrial adhesive Velcro under each ESC when the ears broke. That was 2 years ago.
Bill
Hi Andy, That was a beautiful take off! Sorry to hear what happened! Here are some things I have observed from your pictures and video:
The left tension line for the net was routed on the back side of the left arm instead of the front:
The Y in the tension line (the location of the knot) needs to be adjusted so that the net overlaps the bottom arm as much as possible like this:
Since the props are only one inch apart it’s easy for one prop to break and hit the other prop. Also, if a motor comes off and dangles while still running there is no way the other prop could miss hitting that. However, I think your analysis was correct when you said the right prop broke and a piece of that caused the left prop to break and the off balance prop shook itself off the mount.
Now I must ask: Why did you continue to use throttle after you heard the crack? You made the right decision to land right away but why did you not instantly release the throttle? Did those broken props shake the motor tremendously? Did you notice the shaking? It shook hard enough for a motor to break off the mount so it must have been shaking pretty bad.
A free hanging spinning motor with half a prop on it could do a lot of damage so I’m glad you didn’t get hurt!
Nice landing by the way!
Stay safe my friend!
Andy, Paul is correct that it probably started on the right side and cascaded from there. When I saw the net routing on the left side, I just jumped to conclusions… even though the net on the left wasn’t torn.
My bad! …improper net tensioning was most likely the culprit. I hope you are back in the friendly skies soon!!
Bill
This is an interesting case study on the safety of multi-motor electric. Two props out and the other two were able to push the aircraft and pilot to a safe, or safer, landing. May not have been absolutely necessary but that’s a pilot-in-command decision.
A prop hitting the netting on a single ice is going to be a glide down only and cost a lot more to fix. Potentially motor repair.
I’m completely paranoid about anything that could pull or shake or get blown loose in flight or reach a prop. Still I had a prop strike a loose, unused, battery strap. When i heard it hit i instantly dropped power and landed. An easy choice, I had just launched and was still over my lz. I only cracked one prop blade a few cms in from the tip and I was able to repair it. A very cheap lesson.
Thanks Paul. Yes, I was thinking those knots were not quite tightening the net as much as as they could. I kind of assumed they were in the correct place from delivery but I should have moved them and certainly with all the info from yourself and Bill I will make sure the netting is super-tight for my next flights. Yes, I should have immediately released the throttle. My 1st thought was it might have been a motor arm snapping into place and there didn’t seem to be noticeable loss of power. Super smooth airflow and no other sounds… the flight seemed to be going well! I only landed as a precaution on account of the crack sound. I was unaware of any motor shaking. The only problem I was aware was the crack sound. But in future I will be more attentive! Looking at the video could it be the case that the 2 lower props were shut down by the ESCs or hub?? I will now remove the props and try starting it up to see if the motor is damaged…… I’ve just done that…. All 4 props rotating normally… (I secured the naughty motor temporarily to the side of the arm… it spat out quite a few tiny bits of metal and still feels stiff to turn by hand but I will keep testing to see if it becomes less stiff with time……its a bit noisy and not improving yet with lots of running…. See video on same link….
