Extended Range Fuel Tanks
                                                                                              Patent Pending
Designed and manufactured by
Hotel Whiskey Aviation, LLC

System Design Goals

   HOTEL WHISKEY AVIATION developed the ER Tank system with several goals in mind which included the requirements to avoid excessive modification of any of Van's basic structure or design and to keep the extra fuel load as close as possible to the middle of the CG envelope of most RVs. Additionally, the system was to be reliable in fuel transfer, simple to use, and simple to install, including installation in aircraft that are already flying.

ER Tank System Function

   One of the primary design objectives for the ER Tank system is "Ease of Use". For this reason Hotel Whiskey Aviation has developed the ER Tank system to be simple and reliable when installed, tested, and used properly.

   The Differential Vent ER Tank system uses no pumps and requires no on-board electrical power or guages. It's only control is a pair of simple gate valves that open the path to drain the ER Tanks into the RV mains. The illustrations below show this operation.

   Newer ER Tank systems for the RV-7, 8, and 10 (as well as the 9 they are available) utilize small electric pumps for positive fuel transfer. HWA felt this additional bit of complexity was more than warranted by the benefits afforded with this type of transfer capability.

   Note that each ER Tank kit comes complete with a SAMPLE Flight Manual Supplement but it is up to each customer to do proper flight testing to insure proper in-flight tank function.

How the system works...

   Simplicity is a primary design feature of the ER Tanks which helps to make the system easy to install and use. Here you can see how the system works.

   Fuel flow is controlled by the TRANSFER VALVE or FUEL PUMP (see images below). When the transfer valve is opened or fuel pump switched on, fuel is moved from the ER Tank into the main tank. The ER TANK is vented to the underside of the wingtip and, as such, has a slightly positive pressure applied to it during flight. This very slight pressure differential will cause the fuel to transfer from the ER Tank to the Main Tank in a matter of minutes.

   Operation during flight will require you to feed from the MAIN TANK long enough to make space available to transfer the ER TANK fuel to the MAIN TANK. When enough fuel has been burned from the main tank, you can begin a fuel transfer operation.A complete Flight Manual Supplement is provided with each ER TANK kit but each aircraft owner is responsible to perform flight testing in order to ensure proper system operation.

 


Pricing & Buying
ER Tanks

Back to
ER Tank
Introduction

The SYSTEM
(how it works)

Design
Installation
& Operation

RV-4
Specs &
Performance

RV-6
Specs &
Performance

RV-7 & 8
Specs &
Performance

RV-9
Not Available
at This Time

RV-10
Specs &
Performance

ER Tank system for RV-7 & 8 as well as upcoming RV-9 & 10

   The system schematic below shows the fuel pump between the ER Tank and the main tank. Note that the plumbing has been greatly simplified when compared to the previous method that utilized differential vent pressure and a transfer valve (shown in next image). In this system the pump draws fuel from the ER Tank and lifts it (slightly) to the upper part of the main tank. The vent line on the ER Tank remains in place and is easily located on the underside of the wing near the tip.

ER Tank system for RV-4 & 6

   The differential pressure system uses the slightly higher pressure in the ER Tank to "push" fuel into the main tank during fuel transfer operations. This is controlled by opening the fuel transfer valve located in the cockpit near the wing root area. The positive vent pressure, in combination with the "downhill run" built in to the RV wing dihedral, allows fuel to reliably transfer to the MAIN TANK.

Tank location and C.G. considerations (all RVs)

   Below you can see how the ER TANK is located just ahead of the wing spar. This configuration minimizes changes to the empty and operational C.G. characteristics of your airplane. Note that the overall empty weight of the system is less than ten pounds but you will still need to re-calculate the weight and balance data for your airplane and incorporate this information in your flight operations guide.

For further information or questions about purchasing and
installing ER Tanks, please contact us at:
ERTanks@SafeAir1.com