Garrett Gee Posted March 21, 2023 Report Share Posted March 21, 2023 Went to do a preflight recently before a planned early morning departure and while "burping" the Rotax, heard a slight rattle in the propeller spinner/hub area. This led me to start looking into what the issue was, and finally led to me pulling the propeller from the from the spacer. Found that two of the 6 screws that attach the spinner backplate to the spacer had the heads completely sheared/broken off, and the nut and shaft of the screws were flinging around in the hub area. Decided this was very unusual, and decided it would be a good idea to pull the rest of them. One broke while removing, and the remaining 3 showed signs of corrosion/rust. Airplane is always hangered and has flown in very little rain/precip since it was installed about 1.5 years ago. Anyone else experienced anything like this? Also found a little corrosion on the spinner screws. I love the propeller and fully intend to keep flying it (once screws are replaced). Thoughts on replacing with titanium screws? Any reputable sources for screws and nylock nuts in titanium? Note: The spinner backplate came from the factory already attached to the spacer. Also, the E-Props manuals says these are M5x12 screws, but I have a load of M5s on the shelf, and they don't fit. They appear to be M4. Can anyone else confirm this? Quote Link to comment Share on other sites More sharing options...
Anticept Posted March 21, 2023 Report Share Posted March 21, 2023 You have to buy the hardware from e-props. Also, you need to communicate with them about this issue. They're the ones best able to work with you on the issue. Quote Link to comment Share on other sites More sharing options...
Garrett Gee Posted March 21, 2023 Author Report Share Posted March 21, 2023 1 minute ago, Anticept said: You have to buy the hardware from e-props. Also, you need to communicate with them about this issue. They're the ones best able to work with you on the issue. Thanks. Yeah, I intend to email them tomorrow. Just wondering mainly if anyone else had seen anything similar. As for the hardware, I just found the kit they have for titanium, but not sure it’s worth that price… With shipping and everything, probably close to $175… Quote Link to comment Share on other sites More sharing options...
Anticept Posted March 21, 2023 Report Share Posted March 21, 2023 I do not know what the regular hardware is on e-props bit I felt like it was a disservice to myself to use anything else but the titanium hardware. Titanium corrodes far less in contact with carbon fiber than steel does. Some stainless steels are about as resistant as titanium, but some are really bad, worse than steel. If you have done any wet weather flying, or even when it was only moist out, I would suspect that you might have picked up moisture. Quote Link to comment Share on other sites More sharing options...
Madhatter Posted March 21, 2023 Report Share Posted March 21, 2023 8.8 metric hardware is far less protected for corrosion as compared to aircraft AN and MS hardware which use cadmium plating. My guess is that the bolts on yours were probably over torqued. I have titanium bolts in mine as I do not like the 8.8 metric bolts which also have a much less strength than standard aircraft hardware that I'm used to. I'm sure however they are fine if torqued properly. I have a full set of unused standard bolt kit if you want it for free. Quote Link to comment Share on other sites More sharing options...
Garrett Gee Posted March 22, 2023 Author Report Share Posted March 22, 2023 23 hours ago, Madhatter said: 8.8 metric hardware is far less protected for corrosion as compared to aircraft AN and MS hardware which use cadmium plating. My guess is that the bolts on yours were probably over torqued. I have titanium bolts in mine as I do not like the 8.8 metric bolts which also have a much less strength than standard aircraft hardware that I'm used to. I'm sure however they are fine if torqued properly. I have a full set of unused standard bolt kit if you want it for free. I'm with you there. Wish I could use some AN on the prop. Thanks for the offer. After some thought, probably going to go with the titanium from e-props. Pricey, but probably worth it. Quote Link to comment Share on other sites More sharing options...
Mike Koerner Posted March 22, 2023 Report Share Posted March 22, 2023 Its hard to avoid over-torquing. e-Props calls for the torque on the standard fasteners to be rechecked regularly. That means I need a click on my torque wrench. I have to use a flex drive to clear the gearbox. Seems like about 1/3 of them turn 30 degrees or so before the click each time I check them. I don't know if they are really loosening or if the flex drive is inhibiting the click some way. Quote Link to comment Share on other sites More sharing options...
Madhatter Posted March 23, 2023 Report Share Posted March 23, 2023 That should not happen especially after several checks. A universal joint is definitely not the way to do it. There are torque wrench extensions but calculations must be made. Very easy to do. Quote Link to comment Share on other sites More sharing options...
Anticept Posted March 23, 2023 Report Share Posted March 23, 2023 Or just turn the torque adapter 90 degrees. Where do you buy your adapters madhatter? Every kit I have seen charge WAY too much. Mike: Click type torque wrenches are some of the worst things on the market. Maybe higher end models don't suffer from this issue, but all the ones I have tried are sensitive as hell to temperature and whether I've committed my timely ritual blood sacrifice last wednesday or thursday. Quote Link to comment Share on other sites More sharing options...
Madhatter Posted March 23, 2023 Report Share Posted March 23, 2023 I use a Snap-on digital torque wrench, expensive but accurate. I also never lend it out. I have access to extensions but also have made some. Whatever it takes to do it right. Quote Link to comment Share on other sites More sharing options...
Mike Koerner Posted March 23, 2023 Report Share Posted March 23, 2023 This is a damn good idea. I'm surprised I didn't think of it. I found this adapter on Amazon for $19 - free next day delivery with Prime. just keep the torque wrench roughly aligned with this part and apply the equation: M1 = M2 x L1 / L2 Where: M1 is the torque setting of the wrench M2 is the actual torque applied to the nut L1 is the normal length of the wrench L2 is the extended length of the wrench I do think the U-joint style flex adapter I had been using has not been transmitting the torque repeatably. Thanks! Quote Link to comment Share on other sites More sharing options...
Garrett Gee Posted March 23, 2023 Author Report Share Posted March 23, 2023 Just an update. E-Props responded and said they are now using M5 screws for the spinner backplate, and are sending out replacement screws/nuts and a drill bit at no cost, with instructions to enlarge the old holes to use with the new hardware. Prop was installed in Sept. of 2021, so if you have one from this time frame, they apparently switched from M4 to M5 hardware for the backplane. Quote Link to comment Share on other sites More sharing options...
Anticept Posted March 23, 2023 Report Share Posted March 23, 2023 Follow those instructions with the absolute utmost care! Props and hubs are no joke when it comes to field modifications. Quote Link to comment Share on other sites More sharing options...
Bill3558 Posted March 24, 2023 Report Share Posted March 24, 2023 I spent a few extra bucks for the titanium. Glad I did. Quote Link to comment Share on other sites More sharing options...
Garrett Gee Posted March 24, 2023 Author Report Share Posted March 24, 2023 EP-SL-002_Service_LetterID840_00100.pdf Quote Link to comment Share on other sites More sharing options...
Madhatter Posted March 24, 2023 Report Share Posted March 24, 2023 On 3/20/2023 at 10:55 PM, garrettgee2001 said: Went to do a preflight recently before a planned early morning departure and while "burping" the Rotax, heard a slight rattle in the propeller spinner/hub area. This led me to start looking into what the issue was, and finally led to me pulling the propeller from the from the spacer. Found that two of the 6 screws that attach the spinner backplate to the spacer had the heads completely sheared/broken off, and the nut and shaft of the screws were flinging around in the hub area. Decided this was very unusual, and decided it would be a good idea to pull the rest of them. One broke while removing, and the remaining 3 showed signs of corrosion/rust. Airplane is always hangered and has flown in very little rain/precip since it was installed about 1.5 years ago. Anyone else experienced anything like this? Also found a little corrosion on the spinner screws. I love the propeller and fully intend to keep flying it (once screws are replaced). Thoughts on replacing with titanium screws? Any reputable sources for screws and nylock nuts in titanium? Note: The spinner backplate came from the factory already attached to the spacer. Also, the E-Props manuals says these are M5x12 screws, but I have a load of M5s on the shelf, and they don't fit. They appear to be M4. Can anyone else confirm this? I also have a prop from the same date, I will replace the bolts in question. The other thing that is an issue is the spinner screws, the rivnuts have little or no locking ability. This can cause them to come out and damage a blade it happened on an earlier E Prop I had. I use a small amount of Locktite 222 now. Quote Link to comment Share on other sites More sharing options...
Warmi Posted March 24, 2023 Report Share Posted March 24, 2023 Well, thank you guys for working out all the inevitable kinks typical in any new product … I will probably upgrade a year or two from now once the design gets a bit more mature . Quote Link to comment Share on other sites More sharing options...
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