Warbird Information Exchange

I'll apologize in advance if this topic has already been discussed. Would anyone venture to guess what the R&D (research & development) costs would be to convert a DC-4 to a fire fighting platform with C-130 or similar turbo-prop arrangement. I'm guessing there's 20-30 derelict DC-4 fuselages left in the world that would make this conversion plausible by converting many in order to make it economical with a lower cost per unit. Basler has obviously been successful with their DC-3 conversions and seeing private ownership of ex-military P3 Orions are restrictive and filled with red tape, converting many DC-4's like Basler would eventually become economical. Not to jump the Climate band wagon but wild fires are only going to get worse and I'm thinking not all communities can afford the costs of a 747 supertanker. A more affordable platform needs to be developed but I'm thinking the R&D for a ground up design would obviously out weigh conversion of existing air frames. Other than the 215, 415 & 515 a larger payload like the L-188 Electra needs to be available , seeing that most Electra's have already been pressed into this service, more aircraft will ultimately be needed. I realize many C-130's have already converted for this purpose, so is that a more economical way of addressing this issue?

Completely uneconomic for the few remaining. You would need several hundred air-frames to amortize and warrant all of the R&D and certification costs.

I can't even begin to think of the many, many issues with doing this, or why anyone would think of doing it. It's kind of like saying, "How much would it cost to convert my P-40 into a P-51?".

And since (at minimum) you'd have to redesign and remanufacture the wing to take engines with 3 times more power than the originals, you would undoubtedly be better off starting with a clean sheet of paper and gain the massive benefits of a brand-new airframe.

And why would anyone bother to re-engine a limited pool of DC-4s when there are airfields jam-packed with stored airliners, which are affordable and wouldn't need to be re-engined?

The future of air tankers (and there definitely is one) lies in bespoke, new-manufacture types, not modified ancient airframes, often with questionable history not to mention stress and corrosion issues. And spares supportability.

A new C-130J flyaway cost is somewhere around $51 million. Lop off the military specific stuff and it falls a bit. Top it off, it's got a TC, so much easier to operate and deal with the legal side of things.

if it had to be done, (doubtful) using R-2800s would be easier

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I think it is a good idea use the Pt-6 QEC as used on the BT-67 . It is a great fire bomber able to operate out of small airport , very strong ie no air frame life the only real issue was the engines.

Why not convert retired DC-6 tankers?

http://www.air-and-space.com/Douglas%20 ... ankers.htm

And when you add turbines the fuel capacity will also need to be increased along with a decrease in water capacity. When the plane is throttled back it takes much more time to throttle back up turbines also costs millions to overhaul, with the flying FOD from the fires its just not a good idea.
Besides its not just the recip engine that is hated by the forest service it is the old style airframes as well.

Hijacking this thread for a moment. I think DC-3s are a “buy” investment. I think there are maybe 80 in flyable condition, maybe more. There are hundreds of airframes out there, most are corroded hulks. I think there were at least five airworthy examples lost last year, including two turboprop conversions.
I talked to someone to someone that does t- prop conversions and he said the last five airframes they purchased were trucked in as it’s getting harder to find good airframes.
I saw several at Opa Locka, Florida hauling freight including the bare metal one that later went down in the Bahamas. It looked so odd and ancient, but still making money for its owners, Last week , we flew into LAX, Los Angeles International. There was a C-47 sitting on the cargo ramp, and I also saw it there last year. It looked cosmetically rough but is still earning its keep. There seems to be no end in sight for these airframes.
The DC-4, the engines, R-2000’s are some of the best radials ever designed. To do a turboprop conversion you would want to look at the PT-6 series and their big brother the PW-5 as used on the DHC-7 and DHC-8. You have to think at this point very bright people have looked at the feasibility and it isn’t a good candidate for conversions. A stripped down C-130 would make sense as they have a pressurized cabin and fuel for days. The DC-4 still has to grind around in the weather, doesn’t have air conditioning, etc. Avgas is scarce in Africa and many areas of the world.

Found this list on propliners web site. http://www.proplinerinfoexchange.com/1- ... JAN16-2020 that link says about 170 airworthy including turboprop conversions. More than I thought as I would have guessed about 80 as well. Just gee wiz info anyways.

I think the more interesting question on the Airworthy DC3 subject is how many Radials are still in Active revenue service. Not Turbos, not Museum birds, not privately owned, but real working DC3 Piston Pounders that fly regularly in a commercial application. I would guess around 20-30 ?

What an interesting subject!

You can still find DC-3 types, Convair twins, Beech 18s, Big Dougs, and maybe a couple C-46s still hauling various cargo. Skydiving outfits carry jumpers aloft in DC-3s and Beech 18s. There are still radial-powered airtankers in operation in various parts of the world doing firefighting and oil spill dispersant drops. Are there still any radial-powered Beech 18s doing sightseeing flights in Hawaii? How about radial-powered crop dusters? I know I've seen radial-powered banner tugs (mostly converted crop dusters) flying over tourist areas recently.

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Dean Hemphill, K5DH
Port Charlotte, Florida