Post by zpeedie on Aug 21, 2016 17:56:01 GMT
I'm a new SplashDrone SAR (Fisherman) owner. I am also new to drones, but spent quite a few years in the RC car world (18th scale brushless off-road & 1/8 scale Nitro buggies). I purchased my drone with the sole intent of using it to fly my shark bait out. I fish from shore in Corpus Christi, TX, and I'm too old & fat to kayak my bait over 1/4 mile out through the wind & waves.
Before I get to my question about prop washers, a little back story.... I had two minor incidents (crashes) when I was learning to fly & then coming up with a workable system for flying bait out.
This made me think back to something my father had always told me about how many threads need to be used to achieve the maximum strength of any given nut/bolt. He always told me you want to engage as deep as the diameter of the bolt. I found an example article HERE that goes into even more detail.
I've also seen a number of people mention their props are coming off during water landings. It certainly all seems related. The next day I bought some M6x12mmx1.5mm stainless washers. Fortunately the inner diameter on the washers I bought was only 6.24mm; I looked at others that were over 6.5mm. I felt that was simply too much "slop" and wanted something that could dance around the shaft less. I traded out all of the stock spacers, and I flew 3 more days with this configuration & had no further issues. I've also had no crashes since making this change & can't confirm resolution.
The stock washers/spacers are 6.2x15x3mm. Considering the threads on the props don't come all the way to the edge, I really wanted something with a 6.1mm inner diameter, closer to a 15mm outer diameter, and a 1-1.5mm thickness. I ended up ordering some black nylon washers from Amazon & some titanium washers from Ebay (China).
From what I've read, the 3mm thick washers are a rather recent change. I believe this was done primarily to remove the jello effect from video. Since my drone is used for bait delivery exclusively, you may need to evaluate what this type of change is doing to the quality of your videos. That's not a consideration for me.
Hopefully this story helps someone else out there, but I do have two related questions:
Before I get to my question about prop washers, a little back story.... I had two minor incidents (crashes) when I was learning to fly & then coming up with a workable system for flying bait out.
- Incident 1: I took a test flight in front of my house a few hours after the drone arrived. I didn't fly more than about 50m out & 10m up. It began to toilet bowl, and even though I'd ready about switching to ATTI mode, I was only about 4 ft. off the deck & thought I could land it. I was almost right.
- Damage 1: Two props barely touched the asphalt in the street as the drone landed. It chewed up the ends & shortened the props by about 1-2 inches. Both props also "popped off". Note: they didn't unscrew, actually damaging the threads on the motor assembly slightly. Fortunately I was able to repair the threads & screw a new prop in place on both motors. I was quite glad I purchased spares & immediately ordered another backup set. I also did some reading & re-routed a few wires in the drone & did another calibration. I haven't seen a toilet bowl since.
- Incident 2: The beach where I fish in Corpus Christi does not get plowed. Sometimes there can be quite a bit of seaweed, human trash, and natural trash (drift wood) on the beach. So I got a cheap tarp from Harbor Freight & staked it down with tent stakes... essentially creating a sort of landing zone. Well, that was the
bestworst idea I had. A wind gust lifted the tarp a couple of inches just as I was taking off to fly out a bait. that allowed my hook to catch the edge of the tarp & the next thing I knew, the drone was upside down in the sand. - Damage 2: The sand was a bit more forgiving than the asphalt, and the props suffered no damage (I've flown them 30 times since just fine). However, both props were again sheared off the motor shaft & the threads were again chewed up as a result.
This made me think back to something my father had always told me about how many threads need to be used to achieve the maximum strength of any given nut/bolt. He always told me you want to engage as deep as the diameter of the bolt. I found an example article HERE that goes into even more detail.
I've also seen a number of people mention their props are coming off during water landings. It certainly all seems related. The next day I bought some M6x12mmx1.5mm stainless washers. Fortunately the inner diameter on the washers I bought was only 6.24mm; I looked at others that were over 6.5mm. I felt that was simply too much "slop" and wanted something that could dance around the shaft less. I traded out all of the stock spacers, and I flew 3 more days with this configuration & had no further issues. I've also had no crashes since making this change & can't confirm resolution.
The stock washers/spacers are 6.2x15x3mm. Considering the threads on the props don't come all the way to the edge, I really wanted something with a 6.1mm inner diameter, closer to a 15mm outer diameter, and a 1-1.5mm thickness. I ended up ordering some black nylon washers from Amazon & some titanium washers from Ebay (China).
From what I've read, the 3mm thick washers are a rather recent change. I believe this was done primarily to remove the jello effect from video. Since my drone is used for bait delivery exclusively, you may need to evaluate what this type of change is doing to the quality of your videos. That's not a consideration for me.
Hopefully this story helps someone else out there, but I do have two related questions:
- Has anyone else tested different materials, dimensions, etc?
- When I was working on the threads on the motor assembly, I noticed a small set screw that appears to go against or into the actual shaft of the motor..... or it might. Anyone know how the motor housing comes apart? I have a hobby-grade allen driver that properly fits, but I'm assuming it was assembled at the factory with lock-tite. I'd rather not remove it if I've incorrectly guessed the purpose of that set screw. Also, if it does come apart like I think it does, does anyone sell that part of the motor assembly? I have one each spare CW and CCW, but I would hate to throw out a good motor just because the threads on the shaft were a little mangled.