Prop crack line, is it just the finishing?

[redbaron1982]

Today doing my preflight inspection I found this? The prop is a 3 blade MT. Is for years old. 

I know at some point I will have to refinish it, it has some paint chipping on the tips. 

But my question is: how likely is for the crack line in the picture to be anything more than just the paint/finishing?

Is it safe to fly it like this?

I'd assume that such a crack would have made the blade to fail if it was anything more than just paint. But I need some experts opinion. 

Thanks!

[Hank]

Isn't that a composite blade? I wouldn't expect wood or fiberglass / carbon fiber to Crack neatly across the grain. I also wouldn't expect aluminum to crack neatly like that, either.

Maybe @Cody Stallings has some relevant experience he can share.

[redbaron1982]

Yep, is composite

[Rwsavory]

https://flyhusky.com/forum/index.php?threads/mt-prop-gel-coat-cracks.73/

[EricJ]

Need to look in the maintenance manual for that prop for proper guidance.   Composite props need care specific to their own construction.

 

[redbaron1982]

This is what I found in the operations and install manual for the prop is:

  6.8.3. Small crosswise paintcracks in blade surface

  Crosswise paintcracks are just cosmetic and no reason for repair. In any case, monitor those cracks for possible change. In case of coubt (sic) contact manufacturer.

My understanding is that is something not worry about, but I would like to have another's opinion.

 

[Schllc]

I thought it was composite covered wood. 
the wood grain would 100% be perpendicular to this crack and if it’s wood, I wouldn’t be concerned about that crack. If it’s all composite I’m not so sure. 

[MikeOH]

16 minutes ago, Schllc said:

I thought it was compost covered wood.

Hmm, I've heard of being 'green', but don't you think using compost in a propeller is a little much?

[redbaron1982]

20 minutes ago, Schllc said:

I thought it was compost covered wood. 
the wood grain would 100% be perpendicular to this crack and if it’s wood, I wouldn’t be concerned about that crack. If it’s all composite I’m not so sure. 

It's wood treated with resin, as far I known. 

[MB65E]

Totally acceptable! The entire blade could look like that in fact. It’s a wood core blade wrapped in glass. They have improved their paint products over the last 10y. The white blades’ glass would bubble and crack in the past. Their spinners are Kevlar. Super had to work with. 

Great propellers, just not as nice as the newer Composite Hartzells. But for the price they are awesome!! 
-Matt

 

[Will.iam]

3 hours ago, MB65E said:

Totally acceptable! The entire blade could look like that in fact. It’s a wood core blade wrapped in glass. They have improved their paint products over the last 10y. The white blades’ glass would bubble and crack in the past. Their spinners are Kevlar. Super had to work with. 

Great propellers, just not as nice as the newer Composite Hartzells. But for the price they are awesome!! 
-Matt

 

Do Hartzell make a composite for m20K mooney?  All i see is the old metal version that’s 75lbs even the composite they have for the long bodies is 64 lbs. with my already nose heavy 56 lbs 2 blade, only the MT prop that saves me 11 lbs off the nose is an attractive buy gaining useful load and better t/o climb performance and hopefully with better aft cg will keep current cruise performance too. Although i dread the cowl removal with an additional blade to content with. 

[MB65E]

The two blade option is called the Trailblazer propeller. It’s STC for some Cardinals and other Lycoming powerplants. Hartzell has the similar 3 bladed prop on the Cirrus line with both Lycoming and Continental versions. 
I’m not aware of the STC for the m20 with that prop on it yet. 
Hartzell has the better blade technology at this point. 
-Matt 

[A64Pilot]

The Hartzell composite has been out for years, believe it or not but Maule was one of the first, same prop the Cirrus uses is why I think. If Hartzell made one for a Mooney there is no way I could afford it, especially with their “new”pricing. Price one but sit down first.

MT is composite in name as composite just means made from different materials, MT is a wood prop covered in fiberglass, wood is strong but has issues with moisture, the glass fixes that.

MT USA is based in Deland Fl I’m pretty sure, I’d certainly call them and have them weigh in, I’m pretty sure it’s not unsafe, but boy if you lose a blade the outcome is real bad, so give them a call in the morning.

 

Edited September 29 by A64Pilot

[201Mooniac]

I would contact Peter Marshall from MT to get manufacturer guidance.  His contact info is:

peter.marshall@mt-propellerusa.com

Phone: (386) 736 7762 Extension-204

[MB65E]

Funny I want to put an Extra 300 MT on a M5 540 Maule !! 
Everyone freaks out at the counterweights and says why would you want to do that. Well the old 2 blade Hartzell needs OH and I have two spare MT’s. But no STC for it. 
-Matt

[A64Pilot]

10 hours ago, MB65E said:

Funny I want to put an Extra 300 MT on a M5 540 Maule !! 
Everyone freaks out at the counterweights and says why would you want to do that. Well the old 2 blade Hartzell needs OH and I have two spare MT’s. But no STC for it. 
-Matt

A friend built an Experimental Maule, Chuck is the builder of record but it was built in David Wright’s shop, David is in Moultrie and rebuilds Maules, he did mine.

Anyway it has an IO-540 built for the Red Bull racers and has an MT aerobatic prop with reversing, being an aerobatic prop when oil pressure is lost like on shut down it goes to full pitch, not min like normal, sounds really strange on start-up.

Chuck didn’t get near the speed he thought he would with all the HP and clipping almost 6 ft of wing from a stock Maule. Stock is 235 HP on that airframe and I don’t know how much more than 300 he has.

They put ram air on it like a Mooney but didn’t do it right, theirs is like a funnel and has the big end forward which will build velocity but not pressure, you want pressure so even though it’s counter intuitive you put the small end of the funnel forward to build pressure

I haven’t seen it for years but bet he has the stock 33’ wings on it now, if he still has it.

https://www.kitplanes.com/experimental-maule/

You have an M5? I miss my M6, never should have sold it, it would truthfully be a better fit for the flying I do now.

Edited September 30 by A64Pilot

[Pinecone]

On 9/28/2024 at 6:26 PM, Will.iam said:

Do Hartzell make a composite for m20K mooney?  All i see is the old metal version that’s 75lbs even the composite they have for the long bodies is 64 lbs. with my already nose heavy 56 lbs 2 blade, only the MT prop that saves me 11 lbs off the nose is an attractive buy gaining useful load and better t/o climb performance and hopefully with better aft cg will keep current cruise performance too. Although i dread the cowl removal with an additional blade to content with. 

"They are working on one."

Hartzell rep was at Mooney Max 2023 and said it is in the works.  But no idea when.  Or idea of cost.

[MB65E]

Friend/Customer’s airplane. It flys really nice. Reminds me of a hot rod tripacer. 
Darn thing is a truck! Light in pitch. The old Hartzell keeps trucking but we wanted to play with the Extra 300 prop on it. The Extra was upgraded to the wide cord MT scimitar. The wide cord MT performs about like the Hartzell Claw. Better braking performance than in the past, which means more thrust too. Funny it showed up in braking performance. 
Be fun to play with it. 
The folks that do the MT STC’s sorta laughed at me. 
-Matt

[Cody Stallings]

On 9/28/2024 at 10:52 AM, Hank said:

Isn't that a composite blade? I wouldn't expect wood or fiberglass / carbon fiber to Crack neatly across the grain. I also wouldn't expect aluminum to crack neatly like that, either.

Maybe @Cody Stallings has some relevant experience he can share.

Looks like it’s a crack in the paint layer.

Don’t really wanna downplay that as you now have a week area in the composite layers(paint and filler) that will allow it to flex and let moisture in.

Not good.