[Toobuilder]

Looking to build new fuel tanks for the Rocket and I'm putting together my BOM. The Rocket shares a common airfoil with the -4, -6, -7 and -8, so any of those tank ribs should work. Looking at the Van's store, there is a dramatic difference between the prices of the tank ribs between the models. The -7 is significantly less expensive (like half) than the -8, for example. Any idea why this is so?

 

[Larco]

I could be wrong but I believe the 4 and 6 share the same tank ribs and the 7 and 8 share the same ones but are different than the 4 and 6. The attachment to the wing spar is totally different on the 4/6 and the 7/8. I remember using the 4 ribs on a Rocket and IIRC the 6 ribs use the 4 part number as well. IIRC the 7/8 have a 7 part# for either of the two.

 

[Toobuilder]

According to the Van's site, I see the following prices:

T-404L - $16.00
T-704L - $13.30
T-804L - $43.75

If there is any logic to the series, these are all the equivalent part (position, form, function, etc)

BIG price difference for stamped aluminum.

 

[Ralph Inkster]

When I built up replacement tanks for my current 6A, Vans sent me 7 ribs instead, something about 6 ribs no longer available. I had to cut off the rear flanges & fabricate new ones to conform to the 6 spar, which created a couple extra areas to seal, no big deal. So, I'd go with the cheaper 7 ribs, or 4 ribs if you can still get them.

 

[srt]

My RV-8 plans call out the T-704 ribs. I think the T-804 ribs are probably for the old pre -1 wing that was not fully pre-punched.