Advertised Fuel Tank Volume

[Larry Fulwider]

Do you check the volumes of tanks vs the advertised volume? It would be interesting if you could post what you have found from different suppliers and / or the same supplier with different sizes and shapes.
   The most inaccurate advertised volume I have found is the Great Planes Viper 500 which comes with the Top Flite ARF Nobler. Embossed as  180 cc (and advertised as 6 oz) it is only 132 ml, or 4.5 oz. 

Here is a somewhat random list of some tanks I’ve checked. (Not saying how the ones I’ve built came out compared to the plans!)

Viper 500 6 oz  4.5 oz
Du-Bro 406 6oz  6.0 oz
Brodak BH-489 Med Wedge ATF 4 oz  3.9 oz
Brodak BH-593 Profile 4.5 oz  4.3 oz

Methodology used: Each tank was filled, then fuel withdrawn through normal pickup with 2 oz syringe (and short 1” fuel line) calibrated in cc; syringe volumes withdrawn, noted and totaled. Results converted to ounces, and rounded to nearest .1 oz. Pessimestic estimated accuracy within 3 ml per tank.
    The clunk tanks had all internal plumbing in place, including uniflow tube, with overflow in max fill position.

   Larry Fulwider

[FLOYD CARTER]

Probably, when a tank is designed, volume in ounces is converted to cubic inches, and then the plug (in my case) or the bending template is made.  Actual volume might be a little less than calculated because (1) the overflow tube position leaves a little bit of air volume (2) the tubing displaces a small bit of volume.

It is normal to select a tank larger than necessary, and then measure the fuel load after several flights determine the correct amount.

Is that what everyone else does?

Floyd in OR

(driving directions to OR:  "Follow the cloud".)

[Bob Reeves]

Sullivan 4 ounce slant = 3.75 ounces
Dubro 4 ounce all tubes forward 4.25 ounces

[Jim Thomerson]

Perfect marketed two different size 3/4 oz long wedge tanks.   

[ray copeland]

Agree , agree!!  I use quite a few of the Hayes plastic clunkers, 3,4, and 6 oz. They all hold quite a bit less than stated!!

[Larry Fulwider]

Agree , agree!!  I use quite a few of the Hayes plastic clunkers, 3,4, and 6 oz. They all hold quite a bit less than stated!!

Ray --

Hey, I think those old clapped-out McCoys just use more fuel than you want to admit  

Sullivan 4 ounce slant = 3.75 ounces
Dubro 4 ounce all tubes forward 4.25 ounces

Interesting! The Du-Bro holds more than advertised? I think I have one, I'll check it also.


        Larry Fulwider

[Mark Scarborough]

yes the Dubro does, I tworks out perfectly in a Viper Pylon racer, just enough fuel for a comfort margin when racing. also worked well in My Oriental, fits well, and just the right amount of fuel for my LA 46

[Bob Reeves]

Interesting! The Du-Bro holds more than advertised? I think I have one, I'll check it also.


        Larry Fulwider

The way I checked was to prop the tanks up with opening at the highest point, no plumbing. Filled them up and then sucked them dry with a syringe. What prompted it was I had a 4 ounce Sullivan in my Saito 62 powered stunt ship and it wasn't running as long as the 4 ounce Dubro in my old Score. Wasn't sure if it was the engine or tank. 1/2 ounce difference between the two told the story..