Up close and personal with DC-7 tankers: engine maintenance (2 of 2)

Here are some more photos from Larry Kraus off Q.E.C. stands either ready to install or just removed from the airplane. In order to provide a reference regarding the size of the Q.E.C's, a couple of the photos have people near by. Enjoy!

 

 

 

Up close and personal with DC-7 tankers: engine maintenance (1 of 2)

 

 

The other day Larry Kraus and I were continuing our e-mail exchanges about DC-7 engines when he shared some interesting details on the process of how Butler changes out a bad engine for a good engine. I had wondered how aircraft engines are replaced, so I was very interested in what Larry had to say:

One point of interest concerning the DC-7 engine installation is that the engine, prop, oil system (oil tank/cooler and all lines) and all of the accessories are mounted in a Q.E.C. (Quick Engine Change) assembly. The British call this Q.E.C. a "Power Egg". If you look at the Q.E.C./Power Egg, you can probably see where the term originated, especially if you think of the Q.E.C. without the engine stand.

The pictures here show an engine that Butler brought to us for Tanker 66 in Fairbanks in 1983. The engine itself weighs about 4,400 lbs. The Q.E.C. when it's ready to install weighs a bit over 6.000 lbs. These picture are in sequence, including photos giving a good view of what a Q.E.C. looks like out of the engine stand.

These really are Quick Change assemblies. The record for Butler for an engine change is truly amazing.I was flying as co-pilot to Laddie Lash in 1979 in the old Tanker 67 on a fire near Klamath Falls. We shut #4 engine down because of smoke from an oil leak and flew to Redmond. The problem would take a while to repair and a Q.E.C. was ready that had been run the day before on a test stand.

There were no complications and it took right at two and a half hours from the time we parked in front of the hangar to starting to taxi out for a test flight. The test flight went okay and we were back flying on the fire within four hours of shutting the engine down. That's a record,but it isn't unusual to have the old engine removed and the new one ready to run within four hours.

As I understand it, the Q.E.C. is used for many tankers, and the Q.E.C. can take some time to build. For example, Larry tells me that "It takes a long time to build up a Q.E.C. when you start with a bare mount and an engine in a can. For the DC-7 Q.E.C. at Butler, it takes around 3-4 months per Q.E.C. in the winter with two or three guys working on it."

Up close and personal with DC-7 tankers: power plant specifications

As I was looking around on the web recently to learn some history of the Douglas DC-7's when I ran across a couple of references to power plant (engine) specifications for the four engines on the DC-7. The specification was as follows:

4× Wright R-3350 18EA1 Turbo-Compound radial piston engines, 3,400 hp (2,535 kW) each

Now because of the reference to a 3,400 hp engine, I suspected that these power plant specifications where for the DC-7C not only that but some of the other specifications (not listed here) did not match those that Larry had sent me earlier. They appeared to be for a slightly bigger and heavier aircraft. So, I sent Larry Kraus an e-mail, I include his response below. But first I want to thank Larry for the time he took to write me and walk me through the incorrect power plant (engine) specifications. I am now slightly better able to read power plant specifications in the future. Here is what Larry says:

Our engines are a mix of civilian and military engines.The civil engines are either DA4's or EA1's. With 115/145 avgas,the DA engines were rated at 3250 hp. The EA's were used originally on the DC-7C and had some localized strengthening of the crankcase and improved mounting flanges for the PRT's that allowed an increase to 3400 hp (the C model was larger and considerably heavier than the DC-7.I think that the max take-off weight for the C model was 142,000.

We also use R-3350-42's and a couple of other dash number Navy and Air Force engines that were used on WV-2's and C-121's.These were military versions of the Lockheed Constellation. The P-2 also uses very similar versions of the R-3350. All of these engines are the Turbo-Compound models with the PRT's (Power Recovery Turbines).There are 3 PRT's per engine. They are similar to turbo-superchargers in that they use engine exhaust to spin a turbine wheel,however,instead of the tubine wheel being attached to an air compressor (to boost the air pressure at the carburetor), the PRT's are connected directly to the engine crankshaft via a fluid drive something like an automatic transmission in a car.

The main difference between the DC-7 engines and those in the P-2 is that the DC-7 engines use direct fuel injection with an injector on each cylinder and the P-2 engines use a single large injector into the eye of the internal supercharger that's driven by the crankshaft. I don't remember all of the dash numbers for the 3350 military engines that we use,but if it matters.I think that I mentioned it in my WIX thread somewhere. These are large engines with two rows of 9 large cylinders (18 total). R-3350 means a Radial Engine with a 3350 cubic inch capacity (the internal volume of the cylinders). A large 8 cylinder car engine might be 350-400 cubic inches.

The main point being that all of these engines (DC-7 and P-2) have been de-rated to 2880 hp while using 100 octane fuel. I'll attach a cutaway of a DC-7 engine from the Douglas manual (above) that gives a view of the PRT drive. It's a bit complicated, but the PRT's really do recover horsepower that's just going out the exhaust. With the 115/145 power, each of the 3 PRT's is said to have been worth 150 hp at take-off power.

So, if I were to say anything about the power plant on Butler's DC-7's, I would say the following:

Four 2,880-horsepower Wright R3350 engines.

Thank-you Larry!

This just in, I am adding a couple of posts tomorrow on changing out engines on the DC-7. Stay tuned for more.

Note: double click on the manual page to enlarge the view for easy reading.

Up close and personal with DC-7 tankers: specifcations

This is the first of two articles on specifications of Butler's DC-7's. Tomorrow I will post an article focusing on the power plant (engines) specifications.

Weights of aircraft

Gross weights: The weights of Butler's DC-7's are 113,000 pounds gross with 100/130 avgas. The actual design gross weight was 122,000 pounds gross with 115/145 avgas (no longer easily available). According to Larry Kraus: "the difference is due to reduced horsepower available with the lower power settings allowed with 100/130 avgas. Our take-off power with the higher octane115/145 avgas was 3,250 power per engine. It is 2,880 with the reduced power settings".

Landing weights: Landing weights for Butler's late models DC-7's (T-62, T-66) is 100,000. Larry says that T-66 (a DC-7B) "had some structural reinforcement around the landing gear and also for the flaps. The landing weight for Tanker 60 is 102,000. That airplane has the same power reduction as the straight seven's, so the maximum take-off weigh for Tanker 60 is also 113,000.

Normal take-off weight loaded with retardant: 108,000 pounds.

Turning diameter (on the ground)

I have seen references to the turning radius in specifications of various tankers, so I asked Larry about this. It turns out that the spec that I had from one of the USFS documents (72 feet 8 inches or a diameter of 145 feet 4 inches) was close. I was interested in his comparison of the turning diameter of the DC-7B with the turning diameter of the C-118A (the military equivalent of the DC-6B). He sent me a copy of the turning radius page from the only DC-manual that he has available along with a manual page showing the equivalent information for the C-118A because it shows that the outer wing tip clearance is 74 feet. I want to point out here that the simulator that Larry and his co-pilot use is a C-118A simulator. This is what Larry had to say about turning radii:

This is close to what the USFS info gave for the DC-7. As you can see, it all depends on what you use as a basis for the turning radius.The reason for the slightly larger radius for the DC-6 vs the DC-7,even though the DC-7 is slightly longer with the same wingspan,has to do with the nosewheel steering limits.The DC-7 nosewheel turns 71 degrees either way and I think that the DC-6 only goes 67 degrees.

 

As you can see, the turning diameter of the DC-7B is 142 feet 5 inches and the turning diameter of the C-118A is 148 feet 2 inches

And in an earlier e-mail he spoke about the tight turning radius of a DC-7:

It's tight enough that the airplane doesn't pivot around a locked wheel on the inside of the turn.The inside wheel actually turns backwards.It still amazes me sometimes how tight of a parking spot you can get the DC-7 out of using maximum nose wheel steering.

Fuel Capacity

I'll let Larry explain the fuel capacity of Butler's DC-7's:

The DC-7 and DC-7B with the larger capacity fuel system (top in the above page from the Douglas manual) can carry 5512 gallons of fuel.That's the capacity on Butler's 7's.Our normal tanker fuel load is between 500-600 gallons per engine in the main tanks and 50-75 gallons per engine in the alternates.That allows between 3.5 and 4.5 hour flying.Our oil tanks also hold 46 gallons of 60 weight oil each.Avgas weighs 6 pounds per gallon and oil is 7.5 pounds per gallon.

Retardant Capacity

Butler's DC-7's can carry up to 3,000 gallons of retardant.


Dimensions

I think that this Douglas manual page that Larry sent me showing the dimensions of the DC-7 is self explanatory so I attach it below without comment.

Note: Double click on the manual pages to enlarge the view for easy reading

Up close and personal with DC-7 airtankers: Introduction

 

 

I want to begin by introducing Butler's three DC-7 airtankers: T-60, T-62, T-66. Tankers 62 and 66 are straight DC-7's originally built for United Airlines. Tanker 60, on the other hand is a DC-7B that was built for Eastern Airlines. Larry's tanker, since 1983, is T-62. His co-pilot is Ron Carpinella. A two-person crew, pilot (aka PIC or pilot-in-command) and a co-pilot flies Butler's DC-7s, there is no flight engineer. While each crew has a primary tanker, they do flew each of the three DC-7 tankers. The picture below is the original data plate from Douglas Aircraft for the plane that eventually became T-62. Butler has contracts with the Oregon Department of Forestry (ODF) and with CAL Fire for its DC-7's. As I understand it, specific tankers are committed to specific state contracts. In 2009, T-62 and T-66 were on ODF contracts, where tanker 62 was based in Medford and tanker 66 was based in Redmond. Tanker 60 spent three weeks in 2009 based out of Chico CA on a call when needed (CWN) contract.

The first DC-7 flew commercially for American Airlines in November 1953. Passenger capacity ranged from 74 to 99 in the DC-7's and DC-7B's. I was interested to learn from Larry that "the wingspan was exactly the same from the DC-4 through the DC-7B,although the wing structure changed considerably between models.The fuselage length grew a great deal from the DC-4 through the DC-7 as well.

The heavier DC-7C was slightly longer allowing for an extra row of seats, increasing the passenger capacity to 105. The DC-7C also had longer wings allowing for a larger fuel capacity. By the mid- to late 1960s most major U.S. Airlines had replaced their DC-7 with newer jet planes on their coast to coast and international runs. For more on the history of this magnificent aircraft go here.


 

Early on in my writings on aerial wildland firefighting, someone sent me links to a two-part video starring the DC-7 airtanker. Watching these videos only wetted my appetite to learn more about aerial wildland firefighting. These videos were put together by Bob Webb, one of Larry's former co-pilots who has since moved on from Butler and is now a PIC in his own right. Being an aficionado of aviation history, I enjoyed the images showing historical pictures of various commercial DC-7 airplanes. You will also a couple of images of one of Butler's DC-7 tankers when it was used by United Airlines.  For the last several minutes of part 1, you experience retardant drops from the pilot's point of view (aka the left seat). There is also some incredible footage of a thunder storm. Allow about thirteen minutes to watch this video. It is an incredible video! It may be found here. Note on May 13, 2013, the original link for this video was on Patrick's Aviation, a few months ago I noticed that it was no longer around, but only recently did I find this same video on youtube, but without the audio. Still, you get the pictures and video.

Overview: up close and personal with a DC-7 tanker

Over the course of the last several months, I have run into various references about the Douglas DC-7 air tankers on the web and in books and magazines. Over the summer I saw an article, probably from an Oregon newspaper with a photo of a DC-7 tanker then under contract to Oregon. Recently, I again saw references to DC-7 tankers being under contract to California, this time through an electronic bibliographic database that I accessed through my local public library. Now, I have always had a fondness for the various aircraft in the Douglas DC series, so I asked one of my airtanker pilot friends about these DC-7 tankers. I was lead to Butler Aircraft and then to Larry Kraus, a veteran tanker pilot who has been captain of one of Butler's three DC-7 airtankers.

I have been corresponding with Larry Kraus for the last several days. Thank-you Larry!! This correspondence plus this thread on Butler's tankers, started by Larry on the Warbird Information Exchange forums, form the basis for a series of articles on the DC-7 tanker. Please sit down and join me as we get up close and personal with these beautiful and historic tankers.

Upcoming topics include:

Dec. 7: introduction to Butler's DC-7 tankers and a little history
Dec. 8: specifications - pt. 1
Dec. 9: specifications - pt 2:
Dec. 10: engine maintenance pt 1 and pt 2
Dec. 11: shots of the former passenger cabin of T-62, ballast
Dec. 12: former passenger cabin continued, floating beam
Dec.14: the cockpit
Dec. 16: retardant drop cockpit controls and the drop sequence
Dec. 18: more on the drop sequence
Dec. 21: action shots pt 1
Dec. 23: action shots pt 2
Dec. 30: my reflections

Edited to add a revision I made at Larry's request on March 1, 2010: revisiting ballast, weight and balance, and fuselage stations

K-MAX around the world

Kaman K-MAX

When I was coming up with the list of type 1 helicopters that I just finished writing about, I came upon the Kaman K-MAX. If you have watched the video that I have embedded from the July 2009 airshow in Binghamton NY, then you have seen that the K-MAX has no tail rotor. The K-MAX is a different kind of helicopter using something that is known as synchropter technology where there are contra-rotating, inter-meshing rotor blades. In this design, a tail rotor is not necessary.

The K-MAX is designed for heavy lifting, where it is rated to lift 6,000 pounds with its cargo hook. For specifications, go here. A couple of videos, including a ten minute video introducing the K-MAX, "K-MAX around the world" may be found on this Kaman K-MAX web page. This same video may be found on you tube, I'll make a post embedding that video a little later.

The fire fighting version of the K-MAX is known as the FIREMAX. The FIREMAX has a 700 gallon fixed tank, and I believe that it also has the capacity for bucket operations although I'm not sure how large the bucket is.

Aviastar has a page with information about the K-MAX at this location.

Sikorsky S-64/CH54

Direct link to video


Direct link to video


Direct link to video

I have written extensively about the Erickson Air Crane, so you may recall that Erickson purchased the manufacturing rights and type certificate for the Sikorsky S-64E and S-64F from Sikorsky in 1992. You may also recall that the S-64 is the civilian version of the military CH-54. In addition to manufacturing "new" Aircranes, Erickson refurbishes military CH-54 for civilian use.

Some photos and specifications of the CH-54 may be found here. Wikipedia's entry on the CH-54 may be found here.

As I end this series on type 1 helicopters, I wanted to mention that there are some S-64 "Skycranes" that are flying that are not Erickson Aircranes. Most of these are refurbished military CH-54's. One of these Skycranes is shown in the video.

Edited and updated on November 20, 2017: the video that I originally embedded here is no longer available, so I have embedded three short videos of the CH-54, two are stock footage from Vietnam and the last is from a 1991 airshow. In addition, I have removed two dead links and replaced the links with what I hope is similar information.

Helicopters: S-58

One of the most successful helicopters ever built is the Sikorsky S-58/H-34. The military version is the H-34 Choctaw, serving in the armed forces of over 25 countries. This piston-powered helicopter was first flown on March 8, 1954. Sikorsky developed a turbine conversion kit for the S-58, the S-58T, which first flew on August 19, 1970. There are very few of these models still flying today, and as I understand it, most are used in firefighting and construction operations. I think, but am not quite certain, that the S-58 qualifies as a type 1 helicopter for firefighting, so I am writing about it now.

California Helicopters specializes in refurbishing S-58 and S-58T helicopters. They have a webpage with photos and specifications and another page with weights, performance and design specs.

Desiree Horton, a helicopter pilot who writes The Adventures of a Chopper Chick! weblog has (or still does?) fly the S-58. She summarizes the history of the S-58 here..

Wikipedia has a page on the H-34/S-58 that includes some photos and information on the different variants.

Type 1 helicopters: S-70

The military counterpart of the civilian Sikorsky S-70 helicopter is known as the UH-60 "Black Hawk". The first prototype of the UH-60, a design replacement for the Bell UH-1 or Huey series of helicopters, entered service in October 1974. It entered service in the U.S. Army in 1979.

In addition, there is a nice write-up (with some pictures) of the many variants of the UH-60 and the S-70 here, note that this is a MS Word document. The many variants make direct comparisons difficult.

The firefighting version of the S-70 is known as the Firehawk. The Firehawk can be fitted with a removable 1,000 gallon fixed tank. Existing Black Hawk's can be converted to the Firehawk configuration or the Firehawk can be built as a new model. The LA County Fire Dept has an air operations webpage with pictures of one of their three Firehawks and a description of the fixed tank system.

Type 1 Helos: Croman Helos

Last year I embedded some footage of a Croman Sikorsky S-61 here. That video has been removed by the user. For those of you who have found your here, enjoy this footage of Croman Helos shot in 2008.

Happy Thanksgiving everyone!

Type 1 helicopters: Sikorsky S-61

The Sikorsky S-61 is the civilian version of the SH-3 sea king. The first operator of the S-61 was Los Angeles Airways, using them for passenger service starting on March 1, 1962. Passenger capacity is up to 30 passengers depending on the variant (there are six variants).

Some nice pictures and a video of the S-61 may be found here

Specifications for the S-61 (Frawley, Gerard: The International Directiory of Civil Aircraft, 2003-2004, page 194. Aerospace Publications Pty Ltd, 2003 cited by http://en.wikipedia.org/wiki/Sikorsky_S-61)

Typical Specifications (exact specifications depend on the variant)
Crew: 2 pilots
Capacity: up to 30 passengers
Length: 58 ft 11 in (17.96 m)
Rotor diameter: 62 ft (18.9 m)
Height: 17 ft 6 in (5.32 m)
Disc area: 3,019 ft² (280.6 m²)
Empty weight: 12,336 lb (5,595 kg)
Loaded weight: lb (kg)
Maximum takeoff weight: 19,000 lb (8,620 kg)
Powerplant: 2× General Electric CT58-140 turboshafts, 1,500 shp (1,120 kW) each

Performance
Maximum speed:166 mph (267 km/h)
Cruise speed: 120 kn (222 km/h)
Range: 450 NM (833 km)
Service ceiling: 12,500 ft.
Rate of climb: 1,310-2,220 ft/min (400-670 m/min)

Croman Corporation has S-61's with 1,000 gallon fixed tanks used for firefighting operations. Croman has a page with pictures and videos of their firefighting S-61's.

Type 1 helicopter loading retardant from dip tank

I came across this video on you tube the other day. I a am pretty sure that this is a type 1 helicopter, possibly one of Columbia Helicopters tandem helicopters loading retardant from a dip tank. The helo was fighting fires in 2008 (I believe) in or near Tahoe National Forest in CA.

Type 1 Helicopters: fire fighting with Columbia Helos

To be honest, I am not quite sure which one of Columbia's tandem rotor helicopters is the star of the video, the Boeing Vertol 107 or the Boeing 234 Chinook. But you will get an idea of the fire fighting capabilities of Columbia's heavy lift, tandem rotor, helicopters. The video is shot from a camera on the pilot's helmet. In addition, you will hear audio feed of radio communications.

In addition, you might want to go and watch this video from Columbia. Here you will see more footage demonstrating the bucket operations.

Enjoy!

Type 1 Helicopters: Boeing Vertol 107

direct link to video

Columbia helicopters has a smaller tandem rotor helicopter, the Boeing Vertol 107. This is the civilian version of the CH-46 Sea Knight. Some pictures and a video of the CH-46 may be found here. Go to this location for the wikipedia entry for the CH-46 Sea Knight. I think that the tandem helicopter shown in the video that I embedded here is the Boeing Vertol 107.

Columbia purchased the type certificate to the Boeing Vertol 107 in December 2006. The 107 can carry a 1,100 gallon bucket. Spend a little time exploring the Columbia Helicopter webpage and you will find some photos of the Boeing Vertol and a video gallery featuring the Boeing Vertol 107 and its bigger brother, the Boeing 234 Chinook.

Specifications for the Boeing Vertol 107 may be found here.

Update on October 6, 2014:  The video that I originally embedded here of a Boeing Vertol 107 on wildland fire operations is no longer available. I found a video on the start up and departure of Vertol 107 that I thought you'd enjoy.

Ortega Fire: kudos to aerial firefighters.

I spent about an hour yesterday afternoon watching live streaming of the Ortega Fire burning in southern Riverside County, CA (south and east of Los Angeles. To see a map of this rugged area near the Cleveland National Forest, go here. The fire started late yesterday morning when a tractor knocked down an electric pole with a transformer, sparking the fire.

A couple of things that I want to point out. As I was watching the live streaming, I heard someone say (I assume the news helo reporter) that the winds were light or nonexistent. On the downside, they talked about high levels of fuels (vegetation) "fueling" the wildfire. Another downside, while there were a lot of ground crews fighting the fire, the steep terrain meant that the ground crews had a difficult time getting in and fighting the fire safely. This is the type of fire where aerial firefighting air craft can make all the difference.

Fortunately, there were aerial resources available and fighting the fire from above, two S-2's that I believe were from Hemet-Ryan, and four helicopters including one helitanker.

I have to say that I watched with awe as the fire grew during the time I was watching the live feed. I watched as embers blew down from the top of the ridge to an area down slope. The fire made a quick run up the mountain, impressive. I am told that I was watching something known as the chimney effect. And I watched the helos and the air tankers make drop after drop. See this news report from myfoxla for more information.

The good news is that what was reported as 10% containmentlate yesterday afternoon is now 75% containment. I understand that the latest estimate has firefighters containing this fire by around mid-day today.

Type 1 helicopters: Boeing 234 Chinook

A while back, I was visiting a friend who had spent some time in the military and was familiar with some of the helicopters then in use by the military, including the CH-47 Chinook helicopter. At some point the subject of my blog came up, he briefly mentioned the afore mentioned chinook helicopter, and suggested that I check out Columbia Helicopters.

I did so, and found that Columbia Helicopters uses the civilian version of the CH-43 Chinook, the Boeing 234 Chinook, for fire fighting operations. That was when I decided to spend a little time writing about the Boeing 234 Chinook and other type 1 or heavy firefighting helicopters. According to the Interagency Helicopter Operations Guide (chapter 6), a type 1 or heavy helicopters is defined as:

having at least 15 passenger seats or 5,000 lbs payload, 700 gallon retardant/water capacity, and maximum gross takeoff/landing weight of at least 12,501 lbs.

In the video you will see two of Columbia's heavy lift helicopters in action, the Boeing 234 Chinook and the Boeing 107 Vertol. I will be writing about the Boeing 107 Vertol in a later post. As you can see from the above video, both are tandem rotor helicopters.

The wikipedia entry on the CH-47 Chinook may be found here. More information, including some photos of the Boeing 234 Chinook may be found here.

Columbia has three variants of the Boeing 234 Chinook, the utility, combi, and the LR:

234 utility specifications
234 combi specifications
234 LR specifications

If you go the main page of the Columbia Helicopters web page (sorry that I can provide a direct link, and click on the operations menu and then on flight operations you will find their "fighting wildfires" page. You will see that the Boeing 234 Chinook carries a 3,000 gallon bucket, has a foam tank and is capable of carrying what Columbia calls long-term retardant.

I'd like to thank my friend and aviation historian, T, for his assistance in helping me find the links that I have included here and for the links in upcoming posts.

A quick note

In case any of you are wondering, I do not live anywhere near the flood affected areas. The storm system that has ravaged the southern areas of the Jersey shore and has also ravaged areas south of us is supposed to be pulling away from Jersey today. I understand from the weather channel that areas south of us, for example Norfolk VA were hard hit with flooding and rain fall in the double digits.

update on northeaster off northeast coast

The storm continues to slowly move up the mid atlantic and northeast coast. Myfox Philly has a map of wave heights as reported by buoys and ships. Impressive wave heights. I noted some buoys reporting 15 to 20 foot wave heights. Here is a slide show of some images of the flooding.

The Press of Atlantic City has a web page with reports of the storm and videos, it may be found here.

I understand that the NJ Forest Fire Service has been helping out with evacuations from Wildwood. See this thread on wildland fire for more information.