Fuel tanks

[rival_95363]

Hello all,

I just purchased an rv8/a with an rv4 wing installed. The claim was that it was a stronger wing with the carry-through spar but the downside is that I can only carry 32 gallons vs. 42 gallons. I was wondering if their are any type of wing tip tanks or other types of tanks people have created or installed into the rv 4 wing to get some additional fuel.

Any advice would be great, pros and cons.

Thanks

Randy B.

[dedgemon]

Why would a '4 wing be stronger than an '8. The '4 has a gross weight of 1500 lbs vs the 8's 1800. I sure would want some background on that aircraft if it was mine.

The carry through structure on the '4 wing doesn't make it stronger. It "might" look "stronger" but the real issue is how that wing will behave when loaded.

If I were you, I would contact Vans for some professional advice.

[PIN 37]

Van is definitely the man to contact with this type of question. "Van's the man"

[rvbuilder2002]

Originally Posted by rival_95363

Hello all,

I just purchased an rv8/a with an rv4 wing installed. The claim was that it was a stronger wing with the carry-through spar but the downside is that I can only carry 32 gallons vs. 42 gallons. I was wondering if their are any type of wing tip tanks or other types of tanks people have created or installed into the rv 4 wing to get some additional fuel.

Any advice would be great, pros and cons.

Thanks

Randy B.

Randy

I don't mean for this to sound too harsh but the number one piece of advice (though too late now) is that you should have asked for advice before purchasing this airplane.

Without knowing anything about what the builder did to install the RV-4 wings, the last thing anyone here on VAF should be doing is suggesting ways to add more Fuel (load) to the airplane.

The RV-4 wing was designed for a gross weight of 1500 lbs. The RV-8 was designed for a gross weight of 1800 lbs. It is entirely possible that because of details related to the installation of a 4 wing on an 8 fuselage, that you have an airplane that may not even be capable of a 1500 lb gross weight. The only way to know would be doing an inspection and then some engineering computations on what is there.

The best advice I can think to give you at this point...respect the 1500 lb gross weight limit of the RV-4 wing, which basically makes it a single place airplane. This advice is given in the interest of your safety, and that of passengers you might consider taking with you. Seriously. You really don't know what you have, and neither does anyone else, without doing an analysis of the airplane.

P.S. It is entirely possible that the person who built this airplane is an engineer that was capable of making design changes to make the 4 wing equivalent to the 8 wing, though I doubt this is the case since he told you he used the 4 wing because it was stronger.

[rvbuilder2002]

Originally Posted by PIN 37

Van is definitely the man to contact with this type of question. "Van's the man"

The reality is that Van's is in the business of designing good airplanes and then selling kits for them. They are always willing to help people out with construction problems/mistakes that they make. They are not in the business of analyzing modifications that builders choose to do (that could be a full time job in it self). If a builder is going to make a major modification like this, they better be prepared to do their own engineering, or find someone that can do it for them.

[rival_95363]

Everyone who responded,

I appreciate the remarks and concerns from everyone since my original post. The information about the wing being stronger came from the second owner of the aircraft and not the original. The original owner had it made by a professional builder who I hope to find out has more information and reasoning behind this type of design. If anyone gathers any more information (positive or negative) I would be glad to hear it. Until then I will be contact with the builder to do some more investigating.

Thanks again,

Randy B

[Paul Thomas]

My gut feeling is that something is off. The logical explanation is that the builder was working on a -4 when the -8 was introduced and switched model but kept the old wings.