Need advice on tail

[HURMANAV8R]

All,
I am building a Rocket II and I have seen photos of other RV's that have filled in the hollow spaces at the end of the horz stab and on the elevator were the counterweight goes.
Any suggestions, pro or con?

[SMO]

I was going to fill in the empty space at the back of the HS, even made some foam/fiberglass pieces. Got stuck on an appropriate attachment method - tips are already riveted on. Could try to glue them in with epoxy but don't like the idea of not being able to see how well they are attached. The thought of them to coming loose and jamming up the elevator at the wrong time...........I have decided to leave this for now. I did see where someone inset them about a quarter inch and put a filet in the quarter inch space. Looks like a good idea..... might do that before paint. Meanwhile I just want to get this bird in the air!

WRT to the counterweight space on the elevator, need to leave that open until after paint as rebalancing the elevator will likely require drilling into the counterweight to remove weight. Could try to fill the area after that but wouldn't want to screw up the balance in the process.

[WAM120RV]

Hi

I have done this on my 4 with lightweight glass. No cons so far but looks a lot better and I believe reduces drag as no well for an air pocket to form.

Balancing was not a problem either.

[HFS]

John and the "Bakersfield Bunch" began doing this upgrade way back in the '80's on the early -4's that were being built there. (Maybe John did it on his early -3's and Rocket I, but I don't remember.)

They used expandable foam to fill the cavity, sanded it flat, filled the exposed face with featherfill (or some other light "bondo"), and then finish paint over that. Some builders would use a very light fiberglass to seal the surface instead of bondo, but I don't think John did.

My Rocket is S/N 002 and I chose not to do the mod because of my concern of the potential for water intrusion (especially at the back) and the resultant corrosion opportunity.

Some of the builders would also fill in the ends of the flaps and ailerons.

There are also some "speed mods" out there that actually modify the shape of the inboard ends of the elevators to give better aerodynamics by reducing drag = more speed. Dave Anders has recently completed such a mod on his very fast -4 and believes there is some advantage from the result.

YMMV

David Howe

[HURMANAV8R]

I am interested in any mod that would add a knot or two.
Where can I find some pictures of the mod?

[HFS]

Do a forum search using "Elevator Speed Mod" and you will get a great deal of info, past and present, on the subject.

David