Warp Drive Prop Inspection Issues

[FastEddieB]

I don't know if the CT uses a Warp Drive prop, but I was inspecting the Warp Drive propeller on my Sky Arrow yesterday, and I found two things...

 

 

1) One of the nuts on the backing plate for the spinner is stripped. I don't know if that's a Warp Drive part. For now, I just installed a nut over the nut plate. Would that tiny bit of extra weight so close to the hub cause a balance problem?

 

2) I noticed that one of the leading edge strips is just a tiny bit loose, as seen in this video:

 

 

Anyone know the recommended repair? I did just email Warp Drive and I'll let you know what they say

 

Thanks in advance - over 4+ years the prop has been trouble-free to this point.

 

I also posted this the the "Sport Pilot Talk" site and I'll be monitoring both for responses.

[Roger Lee]

Hi Eddie,

 

The nut if it is on the individual blade is an AN4 and should be replaced and that nut shouldn't be an issue that close to the center of mass. It is too light. If it is on the prop mounting plate where the prop is bolted then that should be a 13mm nut.

 

As far as that leading edge, you absolutely need to stop using that prop right now. I would consider it grounded. It is unsafe. I would also recommend new blades without nickel edges. Rotax doesn't like Warps over 68" and most definitively with nickel edges. The inertia is too high. If it were me I would keep the hub and get three new blades without metal edges and yes there are CT's with Warp 66" props. I had one until just recently when I put a 68" Sensenich 3 blade on.

[FastEddieB]

Thanks.

 

I was hoping the answer would be "Super Glue".

 

I'll let you know what Warp Drive says. I guess new blades every 5 years or so is not the end of the world. I have to check and see what a blade set will cost.

 

I found a nut that fit the spinner screw perfectly. I never know whether something is metric or SAE and usually just have to fish around until something fits!

[Roger Lee]

Hi Eddie,

 

You don't need to buy new blades every 5 years. It is on condition and the Warp blades are very easy to repair because they are solid carbon fiber. You can even do a field repair for a bad nick with super glue and baking soda. I don't think you'll find 3 new blades that bad a price from Warp. Warp uses a clear tape for edge protection on regular blades. It works fairly well. I never got a nick in my blades.

 

I have a used set of 66" 3 blade here if that works?

[FastEddieB]

Here's the result of yesterday's calls.

 

As I said, I thought I had emailed the video to Warp Drive. I had Googled "Warp Drive Prop" and the first hit is warpdriveprops.com and had sent it to their online email link and that was who I called first.

 

Turns out this is just a dealer, not the factory. The fellow's advice was that it should be a simple fix with epoxy, and that the weight of the nut should not matter.

 

I then called the factory (warpdriveinc.com). Spoke to a fellow there and he initially also said epoxy or SuperGlue. I then sent him the video (the other had actually gone to the dealer). On seeing the entire strip move, he said epoxy would still be a satisfactory temporary repair, but that if that was happening they'd really like to take a look. He said a whole new strip, bonded properly, would probably be less than $100. He said he did not feel it was a safety of flight issue, and that even if the entire strip departed the prop, the imbalance would be noticeable, but not dangerous. Oh, and he agreed the weight of the nut was not an issue.

 

Long story short, being a proponent of "Most Conservative Action", I'm going to go ahead and send all three blades to the factory for inspection/repair. I'm down for my annual anyway, so the timing is good, and he said they could turn them around in a few days.

[Roger Lee]

Hi Eddie,

 

I personally think he gave you bad advice.

I think he was nuts over the flight safety issue. If it flings off your entire plane will shake due to that much of an out of balance. You would swear in the cockpit it was coming apart from that much vibration. Now think if that piece leaves the plane, where is it going? It's large enough and has enough mass to kill if it hits someone. What if you are on the ground around hangers and people and I believe an in flight failure wouldn't let you fly home, but cause a forced landing. I have flown Warps with large nicks and it will cause a vibration big enough to get your attention. I can't imagine what loosing an entire metal strip that size of the leading edge. It's a huge portion of that blades balance. I know you take passengers and that adds another layer of liability.

 

Your doing the right thing by sending these back to get re-done. Liability will rest with them and not you using super glue.You didn't consider new blades without the nickel edge? better on the gearbox and engine.

[Tad Olmsted]

Listen to Roger, please!

 

This person gave you some advice that is questionable for the repair. Double check them and be safe instead of sorry. You're on the right track Eddie, and I apreciate your willingness to correct problems when they come up. Keep up the good work.

[FastEddieB]

Update...

 

The factory received the blades and the leading edge rebonding should be straightforward.

 

Darryl gave me permission to post his earlier email to me:

 

Hi Ed,

 

Thanks for the form. I will watch for the blades to arrive and start the work on them right away. As far as the blades with or without the nickel edges this will make no difference whatsoever on the gearbox. With the diameter of propeller you have, the light weight hub and the tapered tip profile we are so far under the allowable limits of the Rotax box there is no reason to question the nickel edges due to weight. A new set of blades just like what you have sells for $885.00 or $705.00 without the nickel. Trading your set of blades in would drop this cost about in half or we can repair your blades for around the $100.00 range based on what you have described.

 

With the holidays, it may be a week or so before they're done. I OK'd the repair, and they said they'd also inspect, refinish and balance all three blades as part of the repair.

 

I'll report back with photos when I get them back.

[FastEddieB]

BTW, Daryl commented on the need for leading edge protection.

 

I opined that my prop was mounted high enough that gravel would not be much of an issue. He said the main problem was rain. He said if you avoid rain, then the strips might not be necessary, but that a plane used for travelling that might encounter rain really needed the strips to avoid erosion - that rain drops were actually worse than gravel.

 

He further said that they had experimented with metallic tape, but that it had not been durable enough.

 

Just passing this along - I'm a newcomer to composite props.

[Roger Lee]

Hi Eddie,

I have used the Warp for many years and used only the taped leading edge protection. My blades were as close to the ground as 10" , both tractor and pusher and I have never had an issue. I don't fly in heavy rain, but light rain for a while was never an issue. Typically we don't fly in rain. For most that's a non issue. The prop up high like yours is a non gravel issue. The clear taped edge works just fine. Don't forget about used car salesmen.

 

What's the length of your prop?

 

Food for thought:

Why do you think Rotax after 21 years with the 912 and Warp prop experience doesn't like a Warp over 68" and none with a nickel edge?

Rotax doesn't have a stake in any prop MFG.

[Mac Bowden]

I've been watching this thread and will add my thoughts to the discussion.

My CT2k has had a Warp Drive prop for the past 5 years with nickel edges. The aircraft was originally under the U.K. CAA regime but this year I placed it on the Irish register. Both Authorities apply one of the strictest engineering requirements for registering ultralite machines, it's called Bcar Section 'S' and if they are happy with the arrangement then I'm O.K.

Living in the extreme north west of Ireland you can expect two days out of three to be rainy and yet the prop has done over 500 hours in some pretty murky conditions without any sign of delamination etc. Factor in that we also fly off short, wet grass strips and we want the power response to be rapid ...... it's a great prop that does exactly what I need and very well priced compared to anything here in Europe.

By the way it's untapered and 66 inches in diameter.

Happy new year to you all and safe flying.

Mac

[FastEddieB]

What's the length of your prop?

 

I had to look it up: 68.5".

 

I've only been in light rain a couple of times, but I know that when circumventing thunderstorms heavy rain can kinda come out of nowhere sometimes.

 

Anyway, for now repair of the prop as is made sense. If and when I have to replace the blades I'll revisit the issue.

 

BTW, the only reason I even have an option is that I'm Experimental. Otherwise I think an LOA would be technically required, and 3i is not in a position right now to issue those.