|Bombs away. In full release mode, the extra-large doors ensure that all the water comes out with enough force to penetrate dense forest canopies. (Photo courtesy of Ascent Helicopters)
Ascent was approached by the BC Forest Service (BCFC) and the State of Victoria in Australia as both were looking for improvements in existing tank technology. Lemke says that there are really very few tanks that are specifically designed for firefighting. Most tanks were actually originally designed for aerial spraying and the drop doors were initially designed simply as a means of quickly dropping the chemicals if the aircraft needed to land quickly in an emergency.
BCFS and the Australians had approached the manufacturers of the day, looking for improvements and refinements, but found the manufacturers were reluctant to make any significant changes to their existing products. Lemke speculates that it may have been that these tanks had originally been certified as long as 40 years ago and the manufacturers were not thrilled at the prospect of having to re-certify those original designs under current regulations.
As an engineer with Ascent Aerospace, Ryan Yip was involved with building the first tank. At the very beginning, they were surprised to discover how difficult it was to find the specialized materials they had decided to use. A company a few miles down the coast by the name of Boeing was ramping up development on something called the 787 Dreamliner and was buying up everything on the market. It wasn’t fun then, but Yip laughs now when he says that today you can’t give it away.
Lemke talks about how they took time to make sure they got it right in the development phase. “The tank has been in operation for almost six years on a Bell 212 on a limited SPC,” he says. “We had manufacturing aspects that we wanted to clean up, we wanted to get the tank lighter and there were a few things that we wanted to change out six years, areas we wanted to improve. We actually wanted to go carbon fibre at the very beginning, but it was not the time. We actually got the approval done in Australia. That’s where our carbon fibre was made, so the shell was made in Australia. Then we brought it to Canada and changed some of the systems on it. Then in the process of the carbon fibre we’ve changed our manufacturing process, to make it a lot less labour intensive and hopefully save costs and also save on weight. Our original tank was a combination aluminum and fiberglass skeleton, encased with a fiberglass shell. We’ve made quite a few improvements on that whole system.”
Originally the tank was controlled by a printed circuit board, Lemke notes, but the first year was dedicated to ironing out the bugs, including a problem with quality control. There were also contamination issues that needed to be worked out, so the Ascent team replaced them with a programmable logic control. “With the programmable logic control, we can trouble shoot and we can reprogram a lot easier,” Lemke said. “We are also in the process of working with SkyTrac out of Kelowna to tie in data tracking and monitoring, so then we can also monitor the systems via the satellite system. That way, if a pilot is having problems we can troubleshoot the tank. The reality is that apart from the circuit board issues, we’ve had very few problems with the tank.”
|How the tank looks when installed on Ascent’s Bell 212. Note the fully retracted snorkel. (Photo courtesy of Ascent Helicopters)
“Another nice thing about our tanks is that we redesigned the cyclic grip, we took the original Bell cyclic grip and added things on to control the tank, so the whole thing is controlled by the pilot’s thumb. There’s no box here and box here. The cockpit ergonomics of it are such that it is easy to use and it doesn’t take a lot of thought process. Actually, you don’t even notice it when you start working the tank, you can keep your head up and we really wanted to reduce the pilot workload.”
“Gallons-per-hour” was a term used by Dan McIvor to extoll the virtues of the Martin Mars water bombers, the simple idea that more water that was lifted and dropped, the better the outcome would be. Lemke has had positive feedback from the contracting agencies where they have operated their system, that they want as much water as possible out of the lake and on to the fire. With the 50001C helitank, the snorkel retracts after it loads, so you don’t have any restrictions on forward flight, other than the regular flight manual restrictions.
|Up, up and away. The tank sports a clean profile and fully retracted snorkel, nothing to impede flight. (Photo courtesy of Ascent Helicopters)
This feature is especially critical in Australia, where, in many locations, they have to truck in water, so they want to get as much as possible. Once the water is on board, it’s quicker getting to the scene of the fire, because of the airspeed restrictions for any type of external load. “With the 50001C, you don’t have that consideration and coming back empty you can move even faster, especially without an empty bucket underneath the helicopter,” Lemke says. “It’s a time and distance formula – your travel time between water source and fire scene is less and you don’t lose any water in transit.”
The new tank gets its baptism under fire when Ascent’s 212 goes into service at the end of April with B.C.’s Rapattack program, based in Salmon Arm. Lemke sees its long-term involvement with that program as a win-win for Ascent and the BC Forest Service. Ascent was able to flight test the original tank for six years in real life situations and the Forest Service watched it happen right before
Lemke describes a normal “day at the office” during the fire season at Salmon Arm as a well-coordinated team effort. “For a standard rap attack mission, we take off with a three-person rappel crew and an attack spotter,” he says. “We fly out, figure out where we’re going to put them on the fire, we put them in and then while they’re getting their gear together, we’re actioning the fire. Then when the crew is ready, we offload their gear. With our tank, we have the option of putting half the water on the fire offload the other half to them. It takes some 45 seconds to offload 155 gallons off the hover. We can keep supplying them water on the ground or we can attack the fire directly. If we’re not needed, we can move on to other taskings.”
There’s also a very unique feature to the Ascent tanks and Lemke says it was almost an afterthought. “The doors are really large, so sealing the doors properly was a real focus for us,” Lemke says. “With the way the doors are designed, the water comes out in a big volume – we almost throw it out. We have to drive those doors open, and we don’t want to interrupt the flow of water coming out those doors. So, we have big seals that inflate.
“When the doors close, the gap can be anywhere from a quarter-inch to three-quarters of an inch, because there is always a bit of flex. It’s a special rubber that does not retain a memory. You won’t get an imprint in the seal, have it stay that way and have a leak. That in turn allows us to do what we call a ‘restricted drop,’ where we can deflate those seals, which brings out a shower curtain of water, so instead of dropping a big load of water we can drop this shower of water. I think the longest we’ve done is 2,000 feet. We do it quite a bit in the Kelowna area; it works great on grassfires.”
|A family portrait. Ascent’s new carbon fibre 50001C helitank (360 U.S. gallons) sits in front, with the old aluminum/fiberglass tank in the rear. Note the large drop doors. (Photo by Paul Dixon)
Ryan Yip watched the 212 in action with the tank on a grassfire outside Kamloops last summer. The fire was stretched out along a rail line, started by sparks from a passing train. Using the restricted drop technique, only two drops were required to control the blaze by showering it along its length. Yip figures it could have taken up to 10 straight dumps to cover the same, which would have taken much longer and wasted a significant amount of water.
The challenges facing fire crews are evolving nationwide with a combination of warmer summers, less precipitation and urban sprawl stretching out further and further in many locales. Lemke is well aware of the new realities in B.C. “I remember the first 18 years of my firefighting, we were fighting fires in the middle of nowhere and now we’re more and more in Kamloops and Kelowna and different areas,” he says. “What we’ve seen a big difference: the interface fire is their focus. So now, in the interior of B.C., for example, now we’re flying in built up areas fighting fires. We’ve been trying to get the Forest Service to bite on NVG. We have our new tank set up so we can ground load. Land and ground load retardant and then with NVG we could work all night in a sustained attack around areas like Kelowna. So, that will be our next focus. We’ll do NVG approval for our 902 next. We’ll see how that goes and look at our 212 for sustained action.”
As the 2014 season is about to unfold, the 360 (U.S.) gallon, carbon fibre 50001C is locked and loaded to take on the world.