Analysis of the poll to design an air tanker

Author Bill GabbertPosted on Categories Fixed wing

Now that over 350 readers of Fire Aviation have expressed their opinions in the poll about the characteristics of an ideal purpose-built air tanker, we can sit back and analyze the results.

Bean, who is a frequent participant here, and the person who originally suggested the idea of asking our readers for their thoughts on the subject, has contributed his interpretation of the polls, and beyond that, looked at existing aircraft that may have some features we would like to have in an air tanker.

Bean’s thoughts as of November 2, 2014:

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“Looks like the jury is pretty much in:

3000+ gal, twin engine turboprop, multi pilot, probably not amphibious, gravity feed tank.

Looked over a fairly long list of cargo and medium attack aircraft: Here’s a site with a comprehensive list of aircraft designs and specs. http://www.flugzeuginfo.net/acdata_en.php

Hard to carry the load with two turboprops … need two 5000+ hp class engines [really thins out existing aircraft designs]. Much over 3,500-4,000 gallons and more than two turboprop engines are a really good idea. May as well build something like a C-130 derivative.

Should have a high mounted wing and high mounted 5000+hp engines to enable use of the large radius props required by the big engines. Added bonus is a coanda effect from that configuration that adds lift.

Dual tandem main landing gear to reduce runway / ramp loading. Enables use of tarmac and dirt fields.

Needs medium to low wing loading [aircraft gross weight / wing area] to enable good maneuverability. A high wing loading results in fairly fast drag rise in turns and reduced maneuverability.

Needs good power to weight ratio [engine power / aircraft gross weight] for adequate single engine performance and better load capability at high density altitudes, better short field performance.

“Beefy airframe”.  Ground attack air tanker work is much harder on airframes than passenger and routine cargo hauling.

Of all the aircraft manufactured, the Transall C-160 is as close as existing aircraft designs have come: http://www.flugzeuginfo.net/acdata_php/acdata_c160_en.php
Original cost was around $28M in today’s dollars. Still cheaper than C-130’s. 35,000 lb payload over 900 nm. Has also been modified for surveillance and command and control.

A significant difference in a point design tanker from a cargo aircraft is that 3,500-4,000 gal doesn’t require a lot of cargo bay volume so the fuselage diameter could be smaller and overall length shorter if a multi-purpose aircraft was not desired.
Bean”

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Bean’s aviation experience: Retired Navy fighter pilot, landing signal officer, aviation safety officer, some post grad work in aero and aircraft structures, pilot time in almost every fixed wing the Navy operated including piston and turboprop.  Navy service from 1969 – 2000. Hold commercial flight engineer and ATP ratings, flew for major air carrier for awhile.

Typos, let us know, and please keep in mind the commenting ground rules before you post a comment.

27 thoughts on “Analysis of the poll to design an air tanker”

  1. Surely hauling heavy loads at low level in relatively hostile conditions is a compelling argument for 4 engines? The amount of surplus installed power necessary to cater for the engine-out eventuality must mitigate against twins.
    Especially in the case of the C160, a 50 year old design with even older engines, built in limited numbers and with no support structure in the US.
    How would that ever compare well with a C130, which whilst admittedly an even older design, has benefited from continual development over a much longer production run, meaning there are many younger airframes around?
    The BAe146 and derivatives seem to make a lot of sense, though airlines were put off by the cost of the 4 engines. I believe they can use the air brakes to fly at higher power settings, to some extent offsetting the slow spool up of relatively high by-pass ratio fans.

  2. Well said, Johnny

    Succinct

    While the general LAT and VLAT pilot and mechanic community seem to understand this to include many well educated general aviation pilots and mechanics seem to also…..

    Some of those Xmas dreams need a large infusion of cash…

    I am sure those operators will agree..

    For those wanting C27J and C160 dreams…….better have parts spares and support……..Jolly Ol St Nick is not supplying that!

  3. It must be getting close to Christmas, everyone seems to be making out their air tanker wish list. New airplanes (exception SEATS) and foreign airplanes are not the culture of the U.S. air tanker industry. Part 137 (ag/fire)) airplanes are hard workers with life cycles and serviceability that MAY require early retirement compared to Part 121 (airlines) airplanes. The “industry” is on the right track

  4. Sure the C-160 would be a very nice air tanker.
    Although it is very sensitive to high temperature/density altitude .

    The maintenance cost and spare parts availability is also a concern.

  5. Yes Leonard

    You got a line on a bunch? How about the dinero to buy them from whatever bank has the pink sheets

    That new outfit on another website….something Klein wildland fire aviation has been talking it up…….

    Where’s the capital and the operators that going to wrestle those away from the bank?

  7. I’m curious, being interested in aircraft in general, but with no fire aviation experience, why the strong preference for turboprop engines versus jets?

    1. Good question, Kevin. Both are “jet” powerplants, one with a gear box and prop connected. Both have a “spool up’ time lags, some manufactures better than others ( time response). Regardless if its a recip or turbine you fly the aircraft on planning and forward energy not unanticipated thrust to accomplish the mission safely.

    2. Turboprops are more efficient [burn less fuel] than turbojet engines at the lower speeds and altitudes where the tankers operate.

      2. I must have missed that on the “test” fuel burn. Never flew a suck and blow. I’m curious what is the difference in fuel consumption between the Bae 146 and the C-130 working fires, both are 3000 gallon air tankers.

        1. Right, Johnny, the BAe-146 and the MAFFS C-130H and C-130J carry 3,000 gallons, but Coulson’s C-130Q holds 4,000 gallons.

  8. A lot of the mentioned twin engine platforms are not happy at the 3000 gal mark.Pushing the flight parameters should be a rare occurrence not a daily one.Of course they can download but thats not what the poll is about.Newer C130’s with GRAVITY tanks make great drops.P-3’s were good but spar repairs very costly.IMHO 3000 and up means either 4 engine turboprop or jet.

    1. Bob,

      You pretty much nailed it … its real hard to find a twin engine turboprop aircraft that can carry 3000+ gallons. The Transall C-160 is the only real possibility. It does show that it would be possible to build a twin turboprop that could meet the poll’s payload requirements.

      Bean

  9. I just don’t see a twin engine tanker working out if you want it to carry 3000 gal plus.

    I am assuming from the rave reviews that the MD 87 performed well after it got the ingestion problem solved?

  10. As a person who uses these tools, I think two overlooked aircraft that have kicked a$$ this year are Neptunes 146 & Aeroflite’s Avro. Slow and stable all day long with now proven tanks of 3000 gal. Folks utilizing these tools are impressed.

    1. my cat hit enter before i was done,,shes hungry…but id like to add,,even though Antonov has long ago stopped construction,why couldnt an “American ” company like Northrup Grumman buy a license to build new built AC for a dedicated fire aircraft?..maybe use it off season for drought watch?..or other things im not smart enough to suggest?..

      1. Bean..thanks for the reply…i had no idea on the payload…me’s not schmart enough for that schtuff…lol..but i mean it..with all the calculations ..i sorta go…ewwww..and just read on..

  12. Gents,

    Gave the P-3 and C-130 designs a miss since they were 4 engine aircraft.
    Passed over the Q-400 [2600 gal] and the CV-580 [2100] gal designs since they didn’t meet the polls desired capacity. Passed over the MD-87 design since it wasn’t a turboprop.

    Lots of designs could be used as starting points for a purpose built tanker but the poll requirements really limited the field.

  13. It would be hard to justify the purchase of a new airplane to fill the roll of air tanker four months out of the year. The “jury” has identified the Conair CV580 and the Erickson MD 87, both are gas producers. There is no perfect air tanker fit. Give me a type three helicopter with a 100 gallon bucket working a lightning strike of 1/2 acre or a VLAT when I need to build some serious line in a short period of time. If there was a surprise (newcomer) this fire season it would have to go to the Erickson folks and their MD 87s.

  14. The Q400 is a beefy airframe. Horizon Air’s N403QX (MSU Bobcat livery) was stripped down by Bombardier in 2012 for evaluation. With nearly 30,000 hours and cycles (the most of any Q as the time), it was structurally sound. The Q400 is a pleasure to ride in (many jumpseat hours) and work on.

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