C-47 "What is it?" for the WIX Brain Trust

[Cubs2jets]

Yeah, OK. They're air scoops/inlets.
In all the pictures I've searched, the do NOT appear in WWII period pictures.
They only appear on some C-47's (never DC-3's). I'm guessing those had a postwar civilian history?
What are they for / what do they ventilate?
Does anyone know a specific installer?

PSAM-C47-Taxi_In-768x512-12.jpg (62.58 KiB) Viewed 4704 times

dc3-city-of-garibaldi-tillamook-air-museum2.jpg (69.92 KiB) Viewed 4704 times

Thank you in advance to the WIX Brain Trust!

C2j

[Larry Kraus]

C-47s with hot air heaters had the scoops on the belly of the airplane for mixing cold air with the hot air from heat exchangers from the exhaust stacks. Earlier versions of the C-47 had steam heaters and didn’t have these scoops. Here are a couple of pages from a C-47A Flight Manual that mention the belly scoops in the text.

IMG_7738 by tanker622001, on Flickr

IMG_7739 by tanker622001, on Flickr

I flew a C-47A and A C-53 in the 1980s, but that was flying in Florida and the Bahamas with freight and we didn’t use the heaters. Most of my DC-3 time was in a Super DC-3 (R4D-8/C-117D) in Alaska on that 1981 Fish Haul. That airplane had an excellent combustion heater with a scoop in the nose and we used it often.

[Cubs2jets]

Larry,

I knew I'd get an answer here on WIX. Thank you for the additional information from the flight manual. I respect (and somewhat envy) your extensive recip time. You always add something to the conversation.

Thanks!!

C2j

[Larry Kraus]

Always glad to be of assistance. That’s what WIX is all about.

[AG pilot]

Always glad to be of assistance. That’s what WIX is all about.

Hear, Hear!!

[Cubs2jets]

Larry and others in the WIX Brain Trust,

From your information, I was able to dig deeper into this. I find that from C-47A-25DL onwards (including C-47B's) the "improved cabin heating" - i.e. a heat muff on each exhaust - system was installed (MANY thousands of airframes). This leads me to a follow up question:

Was there a modification that deleted these from some post war C-47's? I ask because they are not present in all pictures of all civilian C-47.

C2j

[Clifford Bossie]

Larry and others in the WIX Brain Trust,

From your information, I was able to dig deeper into this. I find that from C-47A-25DL onwards (including C-47B's) the "improved cabin heating" - i.e. a heat muff on each exhaust - system was installed (MANY thousands of airframes). This leads me to a follow up question:

Was there a modification that deleted these from some post war C-47's? I ask because they are not present in all pictures of all civilian C-47.

C2j

The War Eagles C-47-90-DL 43-15679 was surplussed from RFC in 1945 and purchased by Phillips Petroleum. It was then converted to DC-3 configuration and part of the modification was deletion of the "heat muff" type heater. In its place a fuel fired heater was placed in the aft part of the fuselage. I believe that is the type of heater that was the cause of the fire in the DC-3 crash that Ricky Nelson and his band were killed in. I will try and post photos later of our heater.

[Larry Kraus]

I remember the night that this accident took place. An unnecessary tragedy caused by a faulty combustion heater, a very cold night and an incompetent crew. I recall that the crew tried to claim that Rick Nelson was free basing cocaine or some such garbage as the cause of the fire. The copilot apparently reset the heater circuit breaker multiple times until a fire started.

A link to the Rick Nelson accident report

https://www.baaa-acro.com/sites/default ... /N711Y.pdf

Link to a more detailed report

https://www.caseygerry.com/2015/04/20/t ... sons-dc-3/

So, some DC-3s did have combustion heaters with other than the hot air system from the exhaust muff. I’ve been looking at pictures of various DC-3s and paying particular attention to the exhaust systems. A number of them have shorter exhaust stacks and a few have multiple short stacks as on the Super DC-3. Those airplanes would most likely have combustion heaters.

High gross Twin Beeches had ejector exhaust with multiple short stacks and had to switch to combustion heaters in the wheel wells from the efficient hot air heaters similar to those on C-47s. The damaged blood circulation in my feet is a testament to how ineffective these heater combustion heater installations could be. Great when everything worked properly, but you were out of luck if the ducting to the cockpit was less than perfect or if you didn’t shut the heater down soon enough on landing. That could pop the over temp circuit breaker in the wheel well. If you forget to check it before the next take-off, you were out of luck for that flight and it would invariably be a 6 hour leg with ambient temperatures below zero Fahrenheit.