RV-8 BUILD: Empennage almost complete - wing kit ordered

[Induna]

UPDATE: As per Vans recommendation I started building the right elevator first, as it is not as complicated as the LH elevator.

Results came out very good. Just need to fit the fiberglass fairings, but that I will only do when I have nothing else to do (whilst waiting for delivery of the wing kit...)

Now I will start the LH elevator..

Pics below

[Induna]

just another comment... i invested in a pneumatic rivet/dimple squeezer and it it TOTALLY worth its money!!! with the hand squeezer I had constant joint pains for days.. lol

It makes the task so much more enjoyable...

[Goose1]

Hi J

For interest do the elevators come with the plates to do SB14-02-05. We have a RV8 with crakes at the top rudder hinge and loose rivets on the elevator outboard hinges. We are fitting the plates now.

Groete

[Induna]

Hi J

For interest do the elevators come with the plates to do SB14-02-05. We have a RV8 with crakes at the top rudder hinge and loose rivets on the elevator outboard hinges. We are fitting the plates now.

Groete

Hi Hans,

no i do not have the doublers. I see that the SB is only applicable where cracks are already found:

NOTE: Installation of this service bulletin as preventative maintenance is not
recommended. If cracking has occurred at an outboard hinge position, install a
doubler only at that position.

The elevator kit i have does have the spar reinforcing plates though. Are there kits that did not have them?

Jacques

[Goose1]

Hi J

For interest do the elevators come with the plates to do SB14-02-05. We have a RV8 with crakes at the top rudder hinge and loose rivets on the elevator outboard hinges. We are fitting the plates now.

Groete

Hi Hans,

no i do not have the doublers. I see that the SB is only applicable where cracks are already found:

NOTE: Installation of this service bulletin as preventative maintenance is not
recommended. If cracking has occurred at an outboard hinge position, install a
doubler only at that position.

The elevator kit i have does have the spar reinforcing plates though. Are there kits that did not have them?

Jacques

Yes the plates must only be fitted were cracks are found, was just wondering if they changed the design.

[Chalkie]

The elevator kit i have does have the spar reinforcing plates though. Are there kits that did not have them?

Jacques

Yes the plates must only be fitted were cracks are found, was just wondering if they changed the design.
[/quote]

Hang on guys, there seems to be some confusion here. The elevators and rudder spars have always had the doublers (on all RV variants) where the Heim joint screws into the K1000-6 anchor nut. The spar cracking is associated with misalignment of pivot centres, loose jam nuts and perhaps aerobatic loads. The repair is relatively simple with the addition of a .063" doubler on the outer face.

I have found many RV-s with the jam nuts loose, this puts all elevator loads onto the two rivets holding the anchor nut. The flexing causes the spar to crack.

I took an old open end spanner, heated it with oxy/acetylene and bent two 90 degree offsets so that the spanner fits flat on the spar and clears the spar flanges. This allows me to tighten the nuts properly.

The picture posted by Goose1 above is a good example of loose jam nuts and all the loads being applied to the rivets holding the anchor nut, which causes stress cracks in the spar web.

I will post a picture later.

[Induna]

Hang on guys, there seems to be some confusion here. The elevators and rudder spars have always had the doublers (on all RV variants) where the Heim joint screws into the K1000-6 anchor nut. The spar cracking is associated with misalignment of pivot centres, loose jam nuts and perhaps aerobatic loads. The repair is relatively simple with the addition of a .063" doubler on the outer face.

I have found many RV-s with the jam nuts loose, this puts all elevator loads onto the two rivets holding the anchor nut. The flexing causes the spar to crack.

I took an old open end spanner, heated it with oxy/acetylene and bent two 90 degree offsets so that the spanner fits flat on the spar and clears the spar flanges. This allows me to tighten the nuts properly.

The picture posted by Goose1 above is a good example of loose jam nuts and all the loads being applied to the rivets holding the anchor nut, which causes stress cracks in the spar web.

I will post a picture later.

Hi Chalkie

this makes perfect sense, thanks. Yes I have checked and my kit does have the spar reinforcement plates on the inside of the spar. I have added a note to self to make sure of the jam nut tightness. Also, your spanner idea is great to ensure that the spanner face is flat against the spar when tightening.

[Chalkie]

If you look at the photo below you will see cracking of the spar web under the heads of the rivets that hold the anchor nut.

I built my RV-6 to plans, but found the heads of the rivets interfered with the bent spanner I made; so on all builds after that, the AN470AD4-4 rivets were replaced with AN426AD4-4 The spar can be dimpled to accept the counter-sunk rivet head and the .063" doubler can be machine countersunk so that the anchor nut sits flat on the doubler.

http://avcom.co.za/phpBB3/download/file ... &mode=view

[Chalkie]

A .jpeg of the modified set spanner...

Attachment-1.jpeg

[Induna]

A .jpeg of the modified set spanner...

Attachment-1.jpeg

Thanks Chalkie! a very good piece of information for all!

[Induna]

UPDATE: The empennage kit is almost complete with only the fiberglass fairings remaining. I also took the step and ordered the wing kit (slow build).

While I am waiting for the kit to arrive I started building another double garage, which will be my primary workshop, as space will becoming an issue very soon... Luckily I need the garage in future, so its not an unnecessary expense...

[Thatch]

I am a taildragger fan (and most of my hours are TD), so naturally I will build the TD version. (i think it's wrong to build a tri-gear RV-8... )

J

I saw nose wheel RV8's for the first time at Oshkosh this year and I must say that they just look wrong.

[Chalkie]

Just a follow up on the picture of the modified set spanner to tighten the jam nut.

I also took a bit of 7/8" 4130 pipe with .040" wall thickness and squared off the one end to allow me to use it to screw in the rod end bearings / Heim joints.

Attachment-1.jpeg

To insert these rod ends to the correct length, Van gives a measurement from the spar web to the bolt centre, great for design engineers but with a self aligning spherical bearing this is difficult to measure. So take the value given and convert it to mm then add half of the outer diameter of the rod end bearing housing (6 of the 7 are 19mm diameter) then add this to the bolt-centre value and make a tool from ally scrap. Now you can set all rod end bearings to the correct value for elevator or rudder alignment.

Attachment-1.jpeg

Take note, the four rivets around the rod end are AN426AD4-5 and not AD470 as called for in the plans. I find the round heads of theAN470 rivets get in the way when trying to tighten the jam nuts

Attachment-1.jpeg

[Induna]

UPDATE: the manufacturing of my wingkit is complete. It is now being crated and will subsequently ship early November. Hopefully I will have it delivered before the end of December...

Also my new workshop (newly build double garage) has been completed, so now I will have sufficient space for the bigger sub-kits to be built...

Good times ahead.

[Fransw]

Nice one! You are making good progress!