Introduction and fuel tank question

Hi to all,

As a prospective "newbie" builder living in Australia, I have followed this excellent forum for some time and I am now in the final stages of planning my RV4 project. I look forward to actively participating and obviously benifiting from the wealth of builder experience available here.

I would be keen to hear from anyone who has used Evan's pre-built fuel tanks, and in particular whether there is anyone who has extended the tank by an extra rib to gain greater capacity. I know this can be easily done, however I would like to hear from those of you who believe this should not be done and why.

Looking forward to joining the RV community and the steep learning curve ahead.

Darren

It would be nice for extending your range, but you'd need to make your own fuel tank skin (I don't know if Evan does this) and cut the f-401 skin to match perfectly. Plus unless you had a ballast weight in the back, depending on what engine/prop combination you use, you'd be hard pressed to fly by yourself with full tanks due to having a heavy fore center of gravity.
Anyone else?

Joe, fuel sits at 70" and the CofG range is 68.7 to 77.4 so there would be no CofG issue surely?

Darren, it would mess up the wing skin layout, so the parts you would need to build it would be custom. I believe there are some tanks (tubes) that slide down inside the cut out holes in the wing ribs from the tips. You might want to research those. It would be much simpler.

Good luck!

RV-6 tanks...

Steve Sampson said:

Joe, fuel sits at 70" and the CofG range is 68.7 to 77.4 so there would be no CofG issue surely?

Darren, it would mess up the wing skin layout, so the parts you would need to build it would be custom. I believe there are some tanks (tubes) that slide down inside the cut out holes in the wing ribs from the tips. You might want to research those. It would be much simpler.

Good luck!

Click to expand...

...would give you an extra 6 gallons, and the tank skins can be bought unpunched. Trimming the outer skins to fit the longer tanks would be trivial.

The other part that would have to be changed is the tank support U-shaped flange on the front of the spar if the spar is not yet riveted.

If you have an old DIY spar, making a longer part to fit the -6 tanks should be easy...

The other option would be to see what John Harmon did on the early Harmon Rockets - these used modified RV-4 wings, and had larger tanks to feed the thirsty 6 cylinders.

Evans tanks

Not sure about extending the tank, but I had Evan build my RV-8 tanks with the capacitive senders and flop tube mods and am very happy with the workmanship. I had Vans ship the parts to him, he built them, and then shipped the completed tanks back to Vans who put them into my wing kit for shipping to NZ.

common mod...

It was not unusual for 4 builders to simply order the RV-6 skins and the RV-6 tank flange (U shaped piece riveted to the spar). I'm sure those parts are still available.

If you talk to Evan, just ask him if he would build you RV-6 tanks for your -4. I'm sure he must have done it before.

Personally, I would have done it if I had thought of it early enough. I don't see any downside at all.

Good luck with your project.

John

DPC

Thanks to all for the replies.

I've read good reports re: Evan's tanks. I'll talk directly with him and discuss the option further. As a newbie builder however, the K.I.S.S. principle is probably going to rule.

Thanks again,

Darren