Christchurch Fires and thoughts about C130 fire bombing

[noooby]

One of these would be more effective than a large plank wing. More water/hour on the fire. 10,000 liters per drop.



I'm 6ft 2, so you get an idea of the size.



Picking up sea water. Fresh water snorkel on the left side of the tank with flexible hose. You dropped it on your first pickup and then the mechanics raised it onto the hook at the end of the day, with assistance for a come-along as the pump head weighs 600lbs and sucks 12,000 liters a minute!

For sea water, this boom was lowered into the water and ram pressure filled the tank in about the same amount of time as fresh water (45 odd seconds). Forward flight over the ocean prevented salt spray getting all over the aircraft. Boom was raised and lowered with an old hydraulic rescue hoist.



Returning to base at the end of the day. The pilots would select water coverage in the cockpit. A computer on the tank would then look at that selection and based on GPS ground speed and Radar Altitude, it would modulate the doors open and shut to ensure the same amount of water hit the same square footage of earth. Worked really well.

There was also salvo mode where it just opened fully as long as the button was pressed. Good for snapping off trees to make a fire break!

All images copyright me, from a life lived a looooong time ago.

[baronbeeza]

I think the barrow you are pushing was a suggestion that the RNZAF C-130 could be used as a type of water bomber. Among the many that have replied here I can see some that have served on 40 Sqdn and they will know for sure just how unique and original such a idea is.

Among those reading and replying here are some ex-RNZAF Engineering Officers, ex- Pilots and SNCO tradesman that have worked on those aircraft.
I know of at least three ex-RNZAF Engineering Officers on this forum and they would know exactly what it takes to get such role equipment approved, purchased and fitted.



Mention of a cheap, oval, alloy tank (with baffles) that could be quickly installed in the rear of a C-130 would have many of us thinking of something like that. I know that is how I pictured your suggestion.

Alloy is not at all strong when under any pressure and you may well find that the load is going to have to be a series of cylindrical based tanks.

We then have to factor in re-charge and discharge flows and pressures and I would have thought there would be a great deal of design work involved.

Aircraft role equipment has to meet the same design standards and airworthiness practices as the aircraft itself, not like something you can tow around behind a tractor.

Have been used for fighting fires also.....

[noooby]

There is no pressure when refilling water bomber tanks, it is all volume and flow. Just like closed circuit refuelling. Fixed helicopter tanks like on the Skycrane are (wait for it) alloy riveted structure. Perfectly sound and very strong. Internally baffled to stop sloshing and vented at the top so that air can replace water when the doors open.

Simple, yet effective.

Simplex belly tanks for helicopters are mostly composite nowadays. Again, no pressure, they just need to be able to carry the weight of water.

[ErrolC]

The MAFFS system (which has the feature of being fittable in only 24hours or so) is pressurised - to push the water out, as far as I can see. Permanently converted water bombers and helicopters with belly tanks 'just' (using controls as nooby says) drop the water out the bottom? It seems a pipe out the back (and a hole in the top, presumably) doesn't do the job that well.

[rone]

That reply shows how narrow your thinking is, and shovels are useful too to dig yourself out of the s--t. No barrow is or was being pushed, was purely thinking out loud, but did not expect to have a suggested means of fire fighting attacked as unworkable when the same method has been in use for 50years o/seas. You appear to not believe alloy can be used for pressure tanks. You might be knowledgeable about aircraft but unless you are also very experienced with pressure vessels I suggest you don't decry someone who does. For what it is worth the MAFFS system Mk11 version uses a stainless steel tank (because of the corrosive retardant), the actual pressure vessel is mounted alongside the liquid holding tank. This tank is not pressurized until the discharge valve is opened, the flow of water governed by the volume of air released into the main tank. This tank is not then under high pressure as you seem to think as the outlet is open the atmosphere. That is just a simplified description, so in the words of Mr. Ripley, Believe it or not.

[baronbeeza]

Yeah, I think we cross-posted. I was referring to the C-130 water bomber concept.

Pressure refueling of aircraft is typically carried out at a standard of 50psi. I had something like that in mind for the replenishment of the water bomber tanks but I also alluded to the discharge pressure. It would appear to be 1200 psi which is extremely high. The airports may have start carts and other high pressure tanks available but they take ages to recharge with a compressor system. Again I am assuming but I would be thinking bottled Nitrogen would be utilised and that would be a replenishment each turn-round.


I referred back to Wiki and it seems that an additional module is used as part of the system. It does the compressed air recharge between trips.

An air compressor module provides air pressure for charging the system; it stays at the airtanker base during air operations and is used to recharge the system between runs

The water and other chemical fluids would no doubt be pumped aboard during the turn-round also.

The helicopter option seems far quicker and easier for our environment. That heavy hauler is impressive also.

[rone]

The main tank would never be pressurized to 1200psi unless the discharge valve was not opened. Even then I do not believe that would bee the case. The air tank alongside is at 1200psi. Consider for a moment if that was a oxy. bottle from a welding set. They are at about 3000psi when first filled. But when welding or cutting the torch pressure is regulated to 50psi maximum. Same principle applies to the tank of liquid. The pressure is regulated to control the discharge rate. As atmospheric pressure is roughly 15psi, then any pressure above 15psi will push the liquid out. The flowrate is dependant on the Volume of air going in as well as the pressure differential above atmospheric pressure. Put simply, that is how it works. With the airborne compressor on the MAFFS Mk2 there is the ability to recharge the air tank while dumping liquid I would assume.

[The Red Baron]

Its a hoary old chestnut using fixed wings to fight fires here,many operators have pushed the fixed wing barrow over the years James/Wanganui Aerowork/Jetspread etc but there appears to be a political reluctance to use fixed wing aircraft much here.
At the end of the day there really aren't enough fires here to warrant large expensive aircraft types.
There are plenty of Crescos and Air Tractors available at short notice with very experienced pilots and 2 or 3 of those working off a strip close to a fire can deliver as much as a heavy aircraft.
Most of the fires here tend to be small and in steep terrain probably more suited to a helicopter/Cresco mix rather than a very large aircraft.

[baronbeeza]

One of the power stations I spent some time at was Cobb.

It is unique in that it has the largest working pressure in NZ with a head of something like 1865 ft. (In my day)





That view shows the outflow from the 6 machines. The first four were all 3 MW each and the rear two were 10 MW each.

That pressure equates to about 850psi at the nozzle entry to the pelton wheels. The smaller machines ran at 1000rpm and the big ones were 3 pairs of poles so ran at 750rpm.

The steam station at New Plymouth ran at about 130 Bar and would spin the turbines at 3000 rpm. (One pair of poles).

I am not sure but I think it was No 3 (or 2) that had a blow out at Cobb, possibly early 1960's.
The story is that it blew a hole in the side of the station there, shot a stream of water across the river uprooting a tree. There was still enough force to then shower back over to infront of the station itself I believe.


High pressure fluid has a lot of force associated with it. That trickle of water from those first four machines would form just a creek and yet we derive 12 MW of electricity from it, day in and day out.

I think the C-130 must get a real boot in the bum when they open those nozzles..

[rone]

One foot head equates to 2.7psi, so your 1865ft head is 690psi. The pipe itself is also a large diameter by the looks of it. That is all hydraulics work in principle, pressure and volume combined result in the power(force) generated. I don't think the water flow from the MAFFS discharge nozzle would affect the speed of the aircraft, the pressure is dissipated to near zero at discharge but the volume remains constant. With your power station the pressure is absorbed spinning the pelton wheel, once the water has passed over the wheel the pressure is also greatly reduced, while the volume (flow) remains constant. This is what gives the rooster tail effect. Same as the flow from a jet boat. It is pressure plus volume that makes things work.

[baronbeeza]

I was working on 32' of water being one atmosphere. That is the rule of thumb I have often used but I was juggling figures from memory regards Cobb.

I can see straight off that one foot is going to be more like 0.5psi.

How 1865 x 2.7 comes even close to 690psi we can only guess.

EDIT, got it... 2.7' to the psi would sound about right..

Others may be interested so we can refer to a chart.

www.kylesconverter.com/pressure/feet-of-water-to-pounds-per-square-inch

Wiki says the head is actually 1955' which converts to 847psi.

en.wikipedia.org/wiki/Cobb_Power_Station

It has been over 40 years since I last worked at Cobb so my memory isn't going too badly.

As Errol and others have indicated, you need either a very large hole to dump several thousand litres of water in quick order or you need to eject it out under pressure.

We all knew one tank with some large dia pipes sticking out the back was never going to cut it.

[rone]

we seem to be back to the original disagreement. I never said anywhere that discharge was purely by gravity, while I did say that a couple of large diameter pipes discharging out the rear door(ramp), I neglected to get all technical and explain that some form of pressurizing of the tank was required. My error in overlooking I am among such technically precise people when I was only putting forward a concept. My thoughts are exactly what the MAPPS Mk1 version was. I must remember for the future.

[ErrolC]

The concept technically works (at some level of sophistication). Whether it worth the costs (which go well beyond the equipment installed on the aircraft) is another matter.

[rone]

Agreed, although in the case of the present fire, the ongoing cost so far must be fast approaching even hiring one from the nearest place which is Indonesia. Specially when the value of the homes alone are taken into account.

[craig]

Given the suggested 24 hr setup time wouldn't it be cheaper to simply lease a bomber from the Northern Hemi. Their winter off season so presumably there would be something available short notice (surely they could get something here within 48hrs)? The cost of ferry etc would still be cheaper than having our own unit to purchase / maintain with crews trained and current.

[baronbeeza]

I doubt the 24 hour set-up time would work down here.

Logic would dictate that we would be in partnership with Oz if bringing a machine down from the NH was going to be an option.
It is not my field but I suspect after all the discussion we as a country will have a system not far removed from where we are now.
The helicopters and Cresco seem to be up to the task.

Using a RNZAF C-130 simply isn't an option and for a whole host of reasons.
For starters we didn't just come up with an original 'inspired' thought here. The aircraft have been here for decades and I have heard all this before.
Nothing has changed. This fire fighting didn't just transpire with the advent of Wikipedia. It has been around for ages and everyone is well aware of the systems.

We still don't have surplus C-130 aircraft. One can't be made available in 24 hours let alone get it to the point where the role equipment can start being installed. Tasking is planned well in advance and we run the risk of losing several days to wasted maintenance if the machine is not required.
Fitting and removing the kit for no reason is a real possibility and a unnecessary downtime.
There is the massive cost of the purchase and modifications and then of course the operational issues discussed here.

It is pointless having invested in the role equipment if you don't have an aircraft to fit it in IMMEDIATELY.

It was an 'idea' that had little merit and most here could see that.

A politician can have a plan that constantly evolves and may try to rewrite history so that the end result looks nothing at all like the original concept.

[baronbeeza]

www.trustpower.co.nz/our-assets-and-capability/power-generation/cobb

[noooby]

Feb 17, 2017 13:26:34 GMT 12 baronbeeza said:

Yeah, I think we cross-posted. I was referring to the C-130 water bomber concept.

Pressure refueling of aircraft is typically carried out at a standard of 50psi. I had something like that in mind for the replenishment of the water bomber tanks but I also alluded to the discharge pressure. It would appear to be 1200 psi which is extremely high. The airports may have start carts and other high pressure tanks available but they take ages to recharge with a compressor system. Again I am assuming but I would be thinking bottled Nitrogen would be utilised and that would be a replenishment each turn-round.

I agree about the fuel pump pressure for refuelling, but the pressure in the wing is zero. From my P-3 days, I believe the rupture limit of the wing was something like 2 or 3 psi if you had a blocked vent? Put 50psi into a wing and it goes kaboom! LOL. Somewhere there is a photo of a Herc wing that did just that from a blocked vent.

Oh, and for those who need to visualise what one load in a Skycrane is..... Take 3 of those bright red fire trucks located all over NZ. Now empty all of them into the tank on the Skycrane and there will be nothing left.

So when I was firefighting in Canberra in 2003 when it burned, we were dropping 3 firetrucks worth of water every 5 minutes. 120,000 liters of water per hour. The firetank has foam tanks built in with 8 or 10 injectors so that the foam is injected into the water for better mixing (done between pickup and drop by the co-pilot). The foam is basically very strong dish soap and breaks the surface tension of the water, allowing it to flow better on the ground and cover more area effectively.

Retardant (the red stuff) is totally different and is not dropped on the fire. It is dropped on the ground ahead of the fire to prevent it from spreading.

Pressurised water bomber systems just seem to complicated for this simple old AME. Let gravity do the work for you and save all that weight and complexity!

For heli firefighting there are two camps. Buckets and Tanks. Buckets are cheaper, but you can't fly as fast with them hanging out the bottom and if foam is used, then there is a chance of contaminating the water supply with foam (if that water supply is used for drinking you'll get diarrhea). Tanks are a closed system, so no worries about water contamination and you can fly faster to and from the fire as they are fixed to the airframe. But, they are heavier and cost more.

[frankly]

Feb 17, 2017 16:29:36 GMT 12 rone said:

Agreed, although in the case of the present fire, the ongoing cost so far must be fast approaching even hiring one from the nearest place which is Indonesia. Specially when the value of the homes alone are taken into account.

I'm not sure you're on Receive Mode. I'll make it simple:


* A range of tactical options are needed to contain and attack a fire

* Those tactics require a variety of tools. The tools need to be appropriate for the tactics

* There is active debate in the fire fighting community about fixed wing versus rotary air attack for smaller-scale fires. In the main, the NZ and AU community prefers rotary for most incidents

* A C-130 sized platform is overkill for NZ tactical needs in any given year

* Even if a 15-20 tonne payload aircraft was needed, a military C-130 isn't the ideal choice

* Fitting role equipment to an aircraft that size is highly specialised, expensive and time consuming.


SaveSave

[Ian Warren]

Feb 18, 2017 5:39:08 GMT 12 noooby said:

For heli firefighting there are two camps. Buckets and Tanks. Buckets are cheaper, but you can't fly as fast with them hanging out the bottom and if foam is used, then there is a chance of contaminating the water supply with foam (if that water supply is used for drinking you'll get diarrhea). Tanks are a closed system, so no worries about water contamination and you can fly faster to and from the fire as they are fixed to the airframe. But, they are heavier and cost more.

One of the biggest things not thought of by the outsider, the other affects 'water contamination' , where the fire was the ocean fill was ideal, .... the not so ideal part is now finding out it was more than likely caused and started by some brain dead prat's, the only other large and serious fire that threatened the public and housing on the Cashmere hills was in the mid 1990's again arson was cause .. teenagers without anything upstairs.