propeller leading edge coating 2

[boo1]

Does any one have information or studies on erosion coatings for propeller leading edges. Leading edge 6061-t6 sheet metal bolted on with molded polyuerthane coating. Speed ~740 ft/sec. One referance I found listed :Irathane-Badg-H.S (Polyureth.) Dow-Adiprene.
Cheers

 

[netlogician]

Some information for you:

1)

http://dodconf.swri.org/2001/Abstracts/Hong-Advaned Rain and Dust erosion.htm

2)

http://www.hartzellprop.com/pdfs/sl180.pdf

3)(more of a product ad)

http://www.flamesprayinc.com/prop-guard.htm

4)

http://www.international-marine.com/news/pdf_propellerdirect/proplr.pdf

5)

http://www.astroexpo.com/news/techpapersdetail.asp?id=35&csort=1&searchtext=erosion+coating

(Regarding erosion and coating protection as it relates to ion thrusters, NOT propellers...also you need to become a member of their site and log in to view this article.)

6)

http://www.microspheres.co.za/contents.htm

Hollow Cenospheres and their usages

 

[WKTaylor]

Boo1...

I have been in general aviation [+homebuilt Acft] a long time: the use of ALUMINUM for a prop leading edge is NOT adviseable... especially 6061!

Wooden props have had brass/bronze leading edges riveted on.

Plastic [FRP] props come with a thin CRES or titanium abrasion strip bonded [integral] onto the leading edges.

Sheet-aluminum is too soft for this function. Anodize hard-coats [including those with PTFE impregnation] may provide short-term resistance to abrasion... but IMPACTS [gravel, sand, etc] are the real killers of prop blades.

Solid aluminum props are made from a much tougher, stronger, harder alloy than 6061... and are shot-peened and anodized.... and the leading edges still get beaten-up!

Suggest a CRES or Titanium LE... and bond or flush-rivet it on... DO NOT use threaded fasteners!

Regards, Wil Taylor

 

[boo1]

This is the existing design system. The blades are 11.75 ft in diameter four blade design and have an ARA-D airfoil shape reversable pitch propeller in a ducted shroud. The blades are a compost carbon reinforced foam core with a glass reinforcemnt and a poly urethane wear coating. The leading edge is protected with the bolted on guards, we are investigating for product improvements

 

[WKTaylor]

Boo1

Is this propellor for a Fixed or rotary-Winged AIRCRAFT???

Your Description leads me to conclude that this "propellor" may be used for another purpose, IE: air-boat, hovercraft, vetilation-fan, wind-tunnel-fan, wind-turbine, etc.

Also, How fast is this prop turning???? Regards, Wil Taylor

 

[boo1]

There are used on a High Speed Hover Craft, the blade speed is ~1200 RPM. The air stream is very dirty with water droplets and sand ect.

 

[WKTaylor]

boo1... You have a real problem!

I cannot believe that the original designers were so naieve about prop-blade leading edge design, as to use 6061-T6 aluminum... there is NO durability to the material.... and NO super magical coatings to prevent damage.

You have the WORST of all worlds...

Abrasive erosion [sand/debris]
water-droplet erosion/cavitation

The most durable coating(s) I can suggest will be a "pain" relative to blade balance and dynamics [add a lot of weight & irregular thickness]; and material compatibility issues.

The only option I can suggest is replacing the aluminum Leading edge with a bonded-on abrasion resistant strip of CRES, titanium or inconel foil. It MIGHT also be possible to apply a uniform thickness, of abrasion resistant ceramic coating by flame-spraying, onto the tough/high-temp foil.

ARE YOU ABSOLUTELY CERTAIN THE BLADE L.E. IS ALUMINUM????? Regards, Wil Taylor

 

[boo1]

Base metal checked out to be 6061 Al. The bonded urethane coating is what we are looking for help with.

Cheers

 

[WKTaylor]

OK, Sorry for the "pulpit" lecture... "gotta do what Ya gotta do"

Try:
AMS-C-83231 Rain Erosion Coating [Black]
AMS-C-83445 Rain Erosion Coating [White]

Apply per either of the following documents:

Boeing Process spec BAC5880
USAF T.O. 1-1-8
Regards, Wil Taylor

 

I’m curious about who originally asked the question on leading edge protection because I believe I know the vehicle you are discussing. Please enlighten us.

 

[forestoak]

As he has a dowty hovercraft propeller, these were bolted on, but the leading edge guard is a not made from aluminium. I take it you don't want to buy an original guard for the prop?
If the aerofoil is an ARA-D, this was off a Textron C7.

 

[boo1]

The system is from the US Navy LCAC. The coating investigation we for a product improvement.

 

[Techcitizen]

one company which might be of help to you is ;
Analytical Services & Materials, Inc.
107 Research Drive,
Hampton, VA 23666 U.S.A.
Tel. 757 865-7283
Fax 757 865-7309.

 

[boo1]

We tested some samples of ASM biocoat last year(Very tough stuff). Additional field test this year....