Main Rotor Blade Filler Blocks

These little wood blocks will kick yer butt lol.

The ones that go into the outer ends aren't too bad to make but the inside ones are a real deal to make. They aren't just triangle shaped as they appear to be. They are also thicker inside than they are outside. Getting these things right is very difficult but with plenty of time and lots of wood it can be done lol. We even made sure they weighed in the same, not an easy task.

We didn't glue them in like the book said to do.

We were afraid if we did, one day we may have to remove them and I can't imagine how hard that would be. Another reason is it would add an unmeasurable amount of glue that would change the weight of the tip, which is not a good thing. The down side to doing it that way is someday one or even both of these tip plugs could be slung out of the blade and if it were to hit someone it would be all she wrote for them.

We checked these on several ships at every fly in we went to and only about 1 out of 50 have them glued in.

March 1st 2004

There was a ship that went down in Ohio (N198BG) owned by Brian and Linda Geoffrion that developed a major vibration in flight.  Brian immediately entered an auto rotation to get the ship down quick as he could but things went amuck at the bottom in the flair and they ended up crashing the ship into some trees just short of hitting a house.  Scuttle butt is Tom Smith from Rotorway and Homer Bell went out to look at the remains of the ship to possibly see what caused it and the only thing they can come up with is that it's highly probable the vibration was from an end plug coming out of one of the main rotor blades. They think the vibration was so bad that it may have caused the tail rotor belt to jump track causing Brian's electric trimable horizional trim fin to deploy in a full aft tilt position causing the ship to nose over and hit the ground.

It will never be known for sure because pieces of the ship were missing or discarded, meaning never found or thrown away by the folks who cleaned up the debris prior to them arriving on the crash site.

The last foot of one of the rotorblades was never found.

This information may or may not be completely acurate so it's best to get it from the before mentioned sources themselves. 

The moral to this story

Be sure to bond these plugs in with blade glue no matter what.

It isn't just the fact that they may come out possibly striking someone with it, it's the loss of the weight of the thing.  When the rotorblades are turning at full RPM the force on the endcaps is a tremendous amout and that little wood plug could weigh as much as or around 300 pounds out there on the end of that blade.  Loosing it would immediately wreak major havic on the rotor system.

Anyhow, Donna and I are glueing ours in ASAP because we sure don't want that to happen to us and we're passing this information along so it doesn't happen to you.  In glueing these blocks in were told to use blade glue coating them with enough glue so they get a good bond without having alot of the glue pool up inside the blade as we push the plugs into the blades.  That way the added weight of the glue will be minimal hopefully not changing the balance of the blades much.  Of course we're going to have to rebalance the blades once we get this finished but as fate would have it we're having to do that anyhow because of a major vibration problem we had when one of our elastomeric bearings has bit the dust already.

You can see what happens in the end in the maintenance section under /vibration problem / March 2004 page

END