Chipped rotor blades?

Paint would wear from both the main and tail rotors with the most wear at the tip(similar to the way props wear on fixed wing a/c). Some chipping would occur but was to be avoided if possible. Badly chipped blades would be replaced. Tail rotors had a tenendcy to be damaged from expended shell casing from both slicks and gunships

Blades had to be in balance and 'in track' or the helo would shake, so "chips" were not really allowed.
Sometimes you would find dings and dents, then you would have to check the blade to be sure it was still balanced. These dents and dings would be then marked as inspected, usually with a red circle with the letters QA inside, (Quality Assurance) to show they were inspected.
The blades are the wings of the helo, so they are kept pretty clean.

Don

it was said on a history channel documentry the blades on the hueys did not last long and had to be replaced every 100 or so hrs flight time if so then the chipping thing is probably minimal because of constant replacements

DURR wrote:

it was said on a history channel documentry the blades on the hueys did not last long and had to be replaced every 100 or so hrs flight time if so then the chipping thing is probably minimal because of constant replacements

While rotor blades have a finite "life", 100 hours seems somewhat low, especially considering that 100 hours...and more...was flown in a month or less.

The phased maintenance cycle on aircraft is different from type to type, but most types have certain inspections and preventive maintenance required at each 100 hours. This often involves removal and reinstallation of blades or possibly replacement due to condition.

All the previous posts concerning "chipping" are correct, significant dents, or chips in the leading edge of blades are idicative of blade strikes and are usually cause for replacement. The big concern is over leading edge spar integrity. Several methods were used on metal blades to give a visual assesment of spar integrity.

H-3s and CH-53s used to have a "BIM" (I forgot what the acronym stood for) indicator on each blade. This setup was based on pressurizing the leading edge spar...the idea was that if pressurization was lost, then there was a breach somewhere in the spar.

CH-46s and CH-47s used an "ISIS" (integeral spar indicating system) indicator on each blade, it was similiar to that used on CH-53s and H-3s except that it was based on a vaccum existing in the leading edge spar.

The problems of both these systems is that a faulty spar could be indicated when in fact the problem was simply a loss of pressurization or vaccum caused by other than a loss of spar integrity. 

Paint erosion on the other hand is a fact of life for rotor blades especially when operating in a field environment and generally doesn't cause any problems. It looks like crap, and the way I used to try to stay ahead of it was by applying Johnsons floor wax to the leading edges of the blades.

HTH

Jonathan Primm

 

The HH52 had the BIM's too, when they showed red you weren't going to fly.
(I also forgot what the BIM stood for)
When I said the blades were kept clean I meant areodynamically of course,  we found that a layer of salt from low hovers over salt water could effect the blade balance especially on the HH65 and HH60 aircraft. So low water hovers caused fresh water wash down on the blades minimum prior to next flight.
(All in all I'd say my memory is not bad for a parachute rigger)

Don

I think you're asking this question with the wrong words, but I know what you mean. Blade wear was minimal at the leading edges because of the paint and primer coatings. In the areas where alot of grit was blown into the air during take-off or landing the paint would erode away with the greatest wear occuring from the tip of the blades and advancing along the surface towards the rotor head in a diminishing pattern. Most visible paint wear was on the tailrotor blades. Surface dings didn't usually chip and had depth and area restrictions, if exceeded they were replaced. Edge dings on the tailrotor from contact with FOD also had limitations that if exceeded would cause replacement but they could be repaired if limitations had not been exceeded. Painting the leading edges could be done at the GS level during phase inspections, but again, there were restrictions on paint depth that could cause irregular airflow over the blade surface so painting was limited. TBO  on the original metal blades was @1500hrs which meant they were removed and overhauled and as long as the blades retained their aerodynamic balance limits were returned to service. Once full blade life was realized they were destroyed. Over time the TBO was increased as documentation records were established and the newer composite blades had a beginning TBO of @2,000 hrs.
Chief Snake
ex UH-1 wrenchbender and knuckle smasher

Come on dude, the memory can't be slipping away that bad. A BIM is an blade integrity monitor.

CS

Sometimes they use some sort of abrasion tape on the leading edge, don't they? At least I think I've seen that on civi AC.

Speaking of dings... I once looked inside a harrier and saw numerous dings in the leading edges of more then a few fan blades. Apparently they can still fly them with some damage to the blades.

Dave
http://www.dpdproductions.com
- Featuring the NEW 'Military Aircraft' Photo CD -

DPD1 wrote:

Sometimes they use some sort of abrasion tape on the leading edge, don't they? At least I think I've seen that on civi AC. Speaking of dings... I once looked inside a harrier and saw numerous dings in the leading edges of more then a few fan blades. Apparently they can still fly them with some damage to the blades. Dave http://www.dpdproductions.com - Featuring the NEW 'Military Aircraft' Photo CD -

I work for a helicopter company operating in the Gulf of Mexico, and yes, the guys in the blade shop apply tape on the leading edges of the blades they repair.

Dings, dents, and gouges on rotor and stator vanes on engines is common and there are cirteria that spell out acceptable limits as to location width and depth of the gouge or ding. Often  repairs by grinding and blending the gouges are often allowed as long as they are not too big and depending on their location along the chord of the individual blades.

Jonathan Primm 

We had a bird develop a sevre vibration while flying back to Denver from Boise,Our best IP was flying it and got it done ok. While checking it out they found one of the main rotor blades had cracked from the back edge of the main spar through the trailing edge of the blade. They were lucky, blade turned out to be defective.

Ok, about 90% of that went over my head.  LOL Let me ask the question differently.

How would the blades (main and tail) look on a typical huey in action during this time?  In otherwords, I can leave them as is.  Right now, I have them painted the correct colors with just a touch of faded paint effect on the tops of the main blades.  Is that all I need?  Or is there any other weathering I need to show?

You could leave them as they are. More weathering in you wish

EDIT: found a pocture late last night, can post tonight if you wish

Thank you, gentlemen.  :)

The wear on both the top and bottom of both blades would be similar. Tail rotor wear would like the same also.

 Notice that is the widest at the end and narrows as it goes towards the helo

Is that some kind of primer showing or bare metal?

Bare metal

Aluminum?  I was actually expecting to have primer of some form showing.

Yes, aluminum primer get worn away also. Best analoge I can think of it taking sandpaper to a car and keep sanding away, metal will show through.

The front leading edge spar was an elongated "D" shape.  I think it was magnesium, not aluminum.  So that is the metal showing.  The thin layer of primer paint goes as quickly as the top coat in "abrasive" conditions.  You would have a thin feather edge showing the under layers of primer. 

 

Melgyver wrote:

The front leading edge spar was an elongated "D" shape.  I think it was magnesium, not aluminum.  So that is the metal showing.  The thin layer of primer paint goes as quickly as the top coat in "abrasive" conditions.  You would have a thin feather edge showing the under layers of primer.

More likely a more durable metal, Nickle Cadmium alloy or Titanium and something else.

 

Jonathan Primm

It could be, I know it was a grainy dark metal.  I'll have to see if there is any mention of it in the few TM's I have at home.