Rudder and elevator suggestion

[Alphalpha]

On the rudder stringers and elevator ribs I recommend a light coat of Proseal on the aft trailing end of these in the area of the last two rivets. This spreads the rib to skin load out beyond the end rivets preventing end cracks there. There’s a lot of wind pounding back there.

 

[dbhill916]

I'm not visualizing where you are recommending placement. Can you mark up a drawing as an example?

thank you,
-dbh

 

[Alphalpha]

Just glue (thin layer) the stringer to the skin with pro seal in the area of the last one or two rivets. Any skin flexing causes that last rivet hole to be the place that flexes and ultimately cracks. The pro seal spreads the load from stringer to skin out some so it isn't flexing at the edge of the rivet.

I've built numerous tail feathers and never had one crack by doing this.


PS, Cessna flap trailing edges have the same problem because these skins do flex a lot especially in the prop blast areas.

 

[rmarshall234]

I had decided to reply before realizing it was YOU, Wheeler.. My reply….

Sounds like a great idea. My first Mechanic’s job out of A&P school ( where Wheeler was one my teachers ) was at Corporate Helicopters in San Diego. I did a lot of sheet metal work there (for whatever reason) and every lap joint or doubler was coated with pro seal first. It was a PITA so I asked Jon McClure the DOM why that was and he explained that helicopters vibrated so much they found it to be a necessary step.

 

[dbhill916]

Thank you for both the graphic and the description. It seems like Mr RMarshall had an excellent instructor!

 

[Alphalpha]

I had decided to reply before realizing it was YOU, Wheeler.. My reply….

Sounds like a great idea. My first Mechanic’s job out of A&P school ( where Wheeler was one my teachers ) was at Corporate Helicopters in San Diego. I did a lot of sheet metal work there (for whatever reason) and every lap joint or doubler was coated with pro seal first. It was a PITA so I asked Jon McClure the DOM why that was and he explained that helicopters vibrated so much they found it to be a necessary step.

Hey Robert, are you building a -15 now?

 

[Webb]

On the rudder stringers and elevator ribs I recommend a light coat of Proseal on the aft trailing end of these in the area of the last two rivets. This spreads the rib to skin load out beyond the end rivets preventing end cracks there. There’s a lot of wind pounding back there.

My RV8 had similar instructions with RTV instead of Proseal recommended. Is this omitted from the RV15 instructions?

Before installing the skin, place a fingertip size daub of RTV inside the trailing edge of the rudder skin at the end of each pair of stiffeners (See “Folded Trailing Edges”, Section 5.7)

 

[rmarshall234]

It seems like Mr RMarshall had an excellent instructor!

I had a few excellent instructors in the program at Miramar College (I highly recommend it) and Wheeler was one of them. Since that time, I have flown formation with Wheeler, gone motorcycle riding, received expert advice from him when building my biplane, and have seen him amongst his peers. The man’s a treasure in the aviation community and a wonderful human.

 

[rmarshall234]

Hey Robert, are you building a -15 now?

Hi Wheeler! No, but I think you are I’ll have to stop by and impede your progress

One (Plans-built) airplane project is enough for me in this life time. The Acroduster is still a work-in-progress but I am finally at the point where I can fly it multiple times in a row and return it to the hangar w/o having to work on it.