Extra (or bigger) holes in tanks

After reading some comments on fill rates on the deltahawk page and witnessing first hand fill rates on a RV I got to fly in last weekend, I was curious as to how to increase it. I could see how it'd be very easy for a line worker to 'fill' the tank and put the cap back on without waiting for it to seep into the other partitions. Not a good thing (but a good reason to always check tank levels on preflight).

So can extra holes be drilled in the tank baffles? Or can current holes (both for fuel and air) be increased in size to let the fuel flow between partitions better?

Thanks,

It works as is! Don't mess with the design. Filling an RV tank is not especially slow. The holes are small so that the ribs act as anti-slosh baffles. There are over 4,000 RVs flying without a problem. Don't create one. One of the taboos of modifications is fuel systems.
Mel...DAR

Fuel it yourself

I would rather fuel it myself or be there when the fuel was put in. But then again I spent 18 years of my life in FBO/airport businesses too. Nothing wrong with letting the line service personnel do it if they are properly advised by you to let the tanks settle and they have pride and care in their work.

Also keep in mind that the holes in the tank ribs serve as baffles that keep that large slug of fuel from surging from one end of the tank to the other. In an aircraft, I don't think you'd want that to happen.

I can imagine a scenario where an "ocean wave" type surge action might affect handling. The slowed movement of fuel from one rip to the next also helps to keep fuel from moving AWAY from the pickup tube if the ball isn't centered.

Like everyone says, don't mess with a design that works.

I too thought about this and I figured it would be a lot easier (and safer) to just tell the fuel guy to let it settle and of course how many gallons you are expecting to get.

Having never handled a Jet A1 nozzle, can anyone say if it's hard to keep the flow rate down to prevent splashing?

Must be fun to wave the big truck over and ask for "30 gallons please".

zsadecki, have you decided to go with Deltahawk? Have given any thoughts to a custom cowl?

I'm still in the dreaming/deciding stage for my engine and avionics. I've tossed around the idea of the supercharged e-subie, deltahawk, 200hp io-360, and recently building a 'super 7' with an io-540.

I really like the idea of a non-normally aspirated engine, as I'll probably be visiting my parents in Idaho (5500ft ele), and when there I'll probably be playing at even higher airports. So I've decided a turbo or supercharger would be VERY nice to have.

I really like the fuel flows on the diesel, too. and the subie isn't so bad either unless you are going all out.

The io-540 would be almost as good as a turbo, though... And the climb rates down low!

So many decisions...

Anyways, I've sent an email to Van's asking their opinion of dilling a couple extra air holes... I'll let you all know how it gets answered. (and I can venture a guess based on everyone's comments).

FYI, Van's answer

Here's what Van's had to say about adding extra air holes:

SHouldn't be a problem, but so long a s the standard holes are there
the tank should fill fairly quickly. The ones I have seen that are
noticeably slow are where those holes are partially blocked with
sealant.

Vans

Click to expand...

So it's not a problem if you want to add an air hole or two in the baffles...

I put an additional set of holes in mine

Both my RV's have an additional set of 1" holes about one inch from the top of each rib to facilitate additional fuel flow during the fueling process.

Also opened up a bit the air bleed holes at the top as well.

Oh my god he messed with the fuel system for improvement

Kahuna