Internal tank being developed for Chinook

A company in Central Point Oregon is developing an internal tank for the Boeing CH-47 Chinook helicopter. Jordan Aircraft Services is constructing a tank engineered by Eric Foy of Perideo LLC in Rogue Valley Oregon that will hold up to 2,800 gallons.

CH-47 Chinook CHI Aviation
CH-47 Chinook operated by CHI Aviation working out of Medford, Oregon December 15. Photo by Tim Crippin.

It will employ an innovative method to help produce a constant flow of water or retardant, according to Ed Jordan, owner of Jordan Aircraft Services. Since the tank system is primarily horizontal in the aircraft, it could be difficult to maintain adequate head pressure at the bottom of the tank as it empties using gravity rather than a pressurized system. As the water is dispensed through a valve in the belly of the Chinook, horizontally mounted 54-inch pistons will push the liquid toward the center of the tank over the valve. This is intended to maintain an adequate head pressure ensuring that the desired flow rate is obtained.

(Photos of the tank on Fire Aviation.)

Mr. Jordan told us that the tank itself is completed, but they are still working on the valve system. The tank has been installed in a Chinook in Medford, Oregon operated by CHI Aviation, formerly known as Construction Helicopters. They expect to be able to begin testing by early Spring.

The personnel at Jordan Aircraft Services have been involved in constructing tanks for a number of aircraft, including S-61 Sea King helicopter, 10 Tanker’s  DC-10, Erickson’s Air-Cranes and their MD-87s.

On a related note, Billings Flying Service now has six Chinooks. The company began acquiring them from the military in 2014 when they purchased two which they flew back to Billings from the Redstone Arsenal in Huntsville, Alabama. The ships were busy in 2015, Gary Blain, a co-owner of the company, told Fire Aviation. He said they expect to have five of them available in 2016.

Mr. Blain said they are following the development of the internal tank closely, but so far they are having success with external buckets.
Thanks and a tip of the hat go out to Tim.

3 thoughts on “Internal tank being developed for Chinook”

  1. I am still bewildered by the fascination of pressure to discharge water/retardant by aircraft. Regardless if the expellant is compressed air or compression (plungers) pushing against head (water) in a vessel it seems like a lot of extra motion, maintenance and expense that in the pass has NOT proven to perform like good old gravity. All the above mention aircraft tank conversions are gravity! I like innovation but the plunger idea is hard to wrap my mind around. Hopefully I will be wrong on this one.

  2. Perhaps an understanding of the limitation on the capability of gravity in a Chinnook will help. The interior space of a Chinook can carry a tank approximately 4′ x 4′ x 24′ long which will hold around 2800 gallons. All of this must be expelled through an existing hole that is 30″x 30″. With associated hardware the gate is around 21″ x 21″. Without any pressurized assistance it would take 8 seconds to drop 1800 gallons. This is a very slow drop and it only gets worse as the head is reduced, taking up to 16 seconds to expel an entire 2800 gallon load. Retardant will be even slower. These numbers are unacceptable as this is barely a trail drop. An 16 second spot drop simply wont work. For comparison, most all large capacity internal tanks have substantial gate door capacity, A crane can salvo a full load in a little over a second. So for emergency operations it is critical to have an instant salvo, and for fire operations there must be coverage levels that work from trail to spot.
    There have been several efforts to make gravity internal tanks for large (over 1500 gallon) helicopters, None have been successful because of the gate restriction. Look at the tank head and gate size of the LAT and VLAT and you will see the size required for effective drops. A 21″ x 21″ gate is too small, but I suspect that engineering a structural change to the airframe ( to allow larger gates) is a far greater problem that engineering a pressurized system.

  3. One way or the other, we must make CH- 47 tanking work since it is the only civilian operated, heavy-lift helicopter in production in the U.S. It’s likely engine, transmission and rotor-blade upgrades will evolve in part, because of military requirements. Relative to other fire helicopters, S-61 and S-64s have a good but sometimes very expensive parts supply chain.

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