I received a text message with a link to the Warp Drive website informing me of a new service bulletin they just issued.

The bulletin applies to the "HP" hubs that are used on the O-235, O-200 and C-90 engines.

The SB is for cracking of the prop hub.

It is also onerous in that it requires inspection "every 15 hours of flight or 12 months". Since you have to pull the prop bolts this takes a bit of time and effort - especially for people like me who fly a lot of hours every month.

They do offer a hub trade-in plan for $150 (a 50% discount according to WD) which apparently eliminates the problem. Guess I'll be spending some more money....

You can read about it here:


Probably not one of those SB's you can ignore.

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Thanks or the info Gary,

I’m going to order the new hub.


I would think it would be worthwhile to try to talk them into replacing this for free. From the bulletin it looks like this was a design error since the they tried to put the put their logo on the hub and the cracks originated from that location.

Be aware of this, I have an earlier hub that is not engraved with

warp drive, this hub is not affected.

if you are affected, the $150 cost for a new hub includes refinishing the blades, 

balancing them and new hardware as well as return shipping.

I’m sure they are losing money on the deal.

Daryl at Warp Drive is a great guy and provides superb customer service.

i am not affiliated with warp drive.


This is my situation also. WarpDrive/Daryl has been totally upfront. Returned my call within a few hours. Their service has been great.

Take note; these hubs/props call for retorque every 10-15 hours, this has always been the case. Maybe have a look at the hub at this time!

Del Clowes

N364DC  Lyc O235?

Gary just saw your post in open forum, I had a similar one under the 601 forum. I have the same concerns you have, I cant live with a 15 hour inspection even if it means changing the prop. I have an email into Warp Drive and if I don't hear back today I will call them and find out my options .I ordered a protractor, but have no idea at what angle the blades should be set at. I do believe I have the hub that is not engraved, but not knowing that yesterday I didn't really look. I will this morning. 


I just heard from Warp Drive, and Dave is correct, the older non engraved hub is not included in this SB. I'm quite relived as I didn't see any easy options. The 15 hour repeat inspection was just too much for me to endure as I said most of my flights are CC that one way exceed 3 hours, so just not an option for me.  

I removed mine today and will send it in tomorrow. I only have 11 hours on the prop since I purchased it, so I’m not too happy to pay an extra $150.

Hi guys

There's some confusion with this SB. I read it a couple times and didn't see that the SB says the replacement hub eliminates the 15 hour inspection. The inference is definitely there but nowhere do I see it stated(did I miss it?). I also don't see any statement that Item 5 under "if no crack is found" on p3 doesn't apply if the new hub is purchased. I do see an offer for a new hub for 150 but no statement in that offer that relates it to the 15 hour required inspection being eliminated.

So I called Darryl again and asked and what I understand is that the 15 hour inspection requirement stands(even with the new hub) until further notice from Warp Drive. I also understand that the 2 cracked hubs are not related to a harmonic balance problem in the engine(s)/prop combination that we have.

Don't take my word for it confirm it to suit yourselves but I see some of you look to be thinking you're out from under the inspection if you spend the 150. That's not how I understand it.

Joe Spencer

Joe;                            I also talked with Darryl and have the same understanding as you. My hub is an early model (no engraving) that has had no problems. The instructions from WarpDrive do however stipulate retorque every 10-15 hrs. Kind of a good time to check the hub condition. 

Del Clowes

I understand the 15 hour bolt torque check is called for regardless of the Warp Drive prop hub you have. My spinner is held on with a lot of screws, and the prop bolts are all safety wired. I am not disputing the fact this should be done every 15 hours, I just don't care for it and I will look for a different option for my 601. Maybe there isn't a better option, but I will check and see what all my options are. 

Hi Gil

I think if you took a survey you would find that no one who has a warp drive prop the torques their 

props every 15 hours. I do mine at the annual condition inspection.

The manufacturer makes those recommendations to Cover their asses.

props are expensive and once you price a few I think you might change your mind.

Sensinich provides the original wood  prop on my AMD built 601XLB, runs about $1,000 plus the spinner and hardware. Figure about $1500. 

The composite Sensinich runs about $3000.

i really wouldn’t worry about it if you have the non service bulletin hub like

i do. 

Just fly the crap out of it.



Well said. Notice in my reply  to Joe I diden't   claim that my prop is torqued @ 10-15 hrs. only that WarpDrive instructed to do so. Mine has been flying for four years and is great. 

You are spot on "fly the crap out of it".



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