[rv8r]

Once again a big thank you for all the support you gave me on the way to get my RV4 airborne yesterday!
While taxiing we found some fluttering of the main landing gear. Not dramatic and only at slow speeds, but if I can get rid of it it would be fine.
The landing gear of the 4 (3 and 6 as well) should have some fluttering tendencies by construction (round steel rods can move in every direction), and the manual mentioned to glass some wooden stiffners in place. I ommitted that step and would be courious to know if that will do the job.
Does it make a difference, and if, any problems with corrosion underneath the fiberglass layup?
Thanks and cheers from Germany (airspace will never be the same around here since yesterday LOL)

 

[gmcjetpilot]

Corrosion may be, depends

Once again a big thank you for all the support you gave me on the way to get my RV4 airborne yesterday!
While taxiing we found some fluttering of the main landing gear. Not dramatic and only at slow speeds, but if I can get rid of it it would be fine.
The landing gear of the 4 (3 and 6 as well) should have some fluttering tendencies by construction (round steel rods can move in every direction), and the manual mentioned to glass some wooden stiffeners in place. I committed that step and would be curious to know if that will do the job.
Does it make a difference, and if, any problems with corrosion underneath the fiberglass layup?
Thanks and cheers from Germany (airspace will never be the same around here since yesterday LOL)

Congratulations! das ist wundervoll!

Yes it makes a difference and no, corrosion is not a problem with the builder manual wood stiffener.

Shimmy = Try to play with tire pressure. Are the wheels balanced? Is the wheel pants and gear fairings installed.

Stiffener = I installed it on my first RV4 and it made a difference. Did I need it? I flew from a larger airport. I had a long taxi distance. The taxi was on a wide open taxi way, where I could taxi fast. One or both main gear could get "excited" and shimmy. It would not stop until I slowed way down again. The Stiffener allowed me to taxi faster with no noticeable shimmy. Slow speeds where never an issue for me even without the stiffener.

If I few from a little grass strip or a small airport, I would NOT have needed the stiffeners or put them on. They do add some weight.

I played with tire pressure, wheel fairing balance, all had some positive effect, but the final modification was the stiffener.


Corrosion = NO, Using wood stiffeners and fiberglass layup, there has been no major problems I have ever heard of. First its not a real wet area (fairing protects the area). Unless you are in a super wet salt environment don't worry about it. Even if water gets in it should be able to get out or evaporate. The fiberglass should seal the steel where it attaches. Where the wood stiffener sits mosture may get in? However it should run out or evaporate. You can use Pro Seal to attach the wood stiffener to eliminate the gap where mosture can go. Of course a good epoxy primer is needed on the steel.

Corrosion = YES, People sometimes have used expanding foam to fill in the gear fairing around the steel gear leg. That has caused bad corrosion. It caused rust and pitting because the foam chemicals and the foam held and attracted mosture. Before Van provided powder coated steel parts the builder had to do all surface prep and primer steel parts. I am sure that in some cases the builder did not do a good epoxy primer of steel parts.


Use good materials and compatible adhesives and compounds. Pro Seal (tank sealant) should be excellent to seal the wood to the gear leg or fill the gap. Once you fiberglass the gear leg it should be resistant to corrosion. Last mosture should not really get into the area if you have the fairing proper. You can always take the gear leg fairing off and look for corrosion.