Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Wolfala on May 24, 2007, 12:08:38 AM
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Just trying to figure out our knowlege base of folks who have actually operated P&W 1830, 2800, 1320, and Curtis Wright 1820s. Is fuel economy the sole reason they were phased out? Did they have lower TBO's then their Horizontally Opposed siblings?
Or is it just a progression of old technology to the new?
Reason I ask is we operated a R-1830 today and tore down a Hydromatic propeller - and i'm just curious if their operation has changed fundamentally throughout the years.
Wolf
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I think technology was the biggest reason they where phased out. They are reliable engines. I have heard stories of P-47s with 4 or 5 cylinders shot to pieces and still made it home. Aerodynamicaly speaking, a radial engine causes lots of drag, as for the horizontal opposed engines there is less of a cross section. I'm an aircraft mechanic so maintainance could be another reason, I know changing magnitos on a radial is a pain, they are at the rear of the engine, opposed engines have them mounted on top.:cool:
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Magneto placement depends on the engine. I think the R-2800 in the F4U had them mounted on top in front of the first row of cylinders.
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I have run the 1340, and 2800. Plus several of the Wright engines.
I believe technology just surpassed them. With the advent of the turbine, we have just bypassed the radial engine technology. The turbines on turboprops can simply fly for longer TBO, get better fuel economy (longer range), weigh a lot less, ease of maintenance, and in some cases produce more HP than the radial.
As for TBO's, the 2800's we use today get around 200 hours, then we rebuild them to prevent items from wearing out and needing replacement. Parts are just getting very hard to find.
FYI, on the 2800, the magnetos are mounted on the forward reduction gear cases. Same for the 1340. As for changing them being a pain, naw, you just need practice doing it, thats all. Once you have done several you learn the tricks of installation.
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Ok, I stand corrected on the magnito placement. Not all radials have the mags located on the rear. I have only worked on the R-985 Wasp Jr. like this one, wich was on a Beech 18.
(http://i142.photobucket.com/albums/r94/steveg79/r-985_wasp_junior-02.jpg)
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Originally posted by Bodhi
I have run the 1340, and 2800. Plus several of the Wright engines.
I believe technology just surpassed them. With the advent of the turbine, we have just bypassed the radial engine technology. The turbines on turboprops can simply fly for longer TBO, get better fuel economy (longer range), weigh a lot less, ease of maintenance, and in some cases produce more HP than the radial.
As for TBO's, the 2800's we use today get around 200 hours, then we rebuild them to prevent items from wearing out and needing replacement. Parts are just getting very hard to find.
FYI, on the 2800, the magnetos are mounted on the forward reduction gear cases. Same for the 1340. As for changing them being a pain, naw, you just need practice doing it, thats all. Once you have done several you learn the tricks of installation.
How does it work with sourcing parts? Do you have to fab them yrself or just canibalize from somewhere?
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Some of the major engine rebuilders have good stock still> Plus, individual owners (like the one I work for) spend an aweful lot of money on buying up spare parts supplies and anything that comes available. We then properly catalog, NDT (nondestructive testing), and properly preserve for storage all the parts we anticipate needing over the life time of the aircraft. That way we are never caught with our pants down so to speak...
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I read in a book somewhere that from an efficiency standpoint, piston engines lose out to turbo-props at about the 400 HP range. That's why, so the book said, the horizontally opposed engines, like the Lycoming O-720 series (at a stock HP rating of 400) were the largest ever designed. Now that Walther and some others have turbo props that hit the top of that range, we'll probably not see anything larger. PT-6 in the Caravan and the other single engine props are rated at 600 SHP, so, at least from a currently manufactured aircraft standpoint, the books' contention appears to be true.
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I've got a great many hours running R-1820s and R-2800s. However, that dates back to 1979. Somewhere, I have a NATOPS for the Grumman C-1A....
My regards,
Widewing
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Widewing, you flew the C-1 COD? That is a pretty awesome aircraft. We used to have a guy that had one, and we used it as a support bird for airshows and such. We could load damn near anything into it and the darn thing would take off! I saw pictures one time way back that showed them loading jet engines into one for apparent delivery to a CV.
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Originally posted by Bodhi
Widewing, you flew the C-1 COD? That is a pretty awesome aircraft. We used to have a guy that had one, and we used it as a support bird for airshows and such. We could load damn near anything into it and the darn thing would take off! I saw pictures one time way back that showed them loading jet engines into one for apparent delivery to a CV.
I was the flying crew chief on Saratoga's C-1A. Same on HU-16. FE on the C-131 and C-118.
The C-1A was extremely capable in the COD role. We could haul just about anything we could stuff into the fuselage. I've loaded the cabin so full that I had to crawl in thru the cockpit overhead hatch to get aboard.
Aside from being aboard whenever the plane flew, I was responsible for doing the pre-flight ground checks. This included run-up and mag checks. I'd usually taxi to the run-up circle and do a full power run-up, then taxi back and pick up the pilot or pilots. If we were not transporting passengers, only one pilot was required and I had many opportunities to fly right seat.
I did the same thing with the other aircraft. However, the C-131 and C-118 had nosewheel steering and were easy to taxi. You taxied the the C-1A like a fighter, using brakes, differential power and rudder (not very effective). In flight, the Flight Engineer has different duties than a crew chief as he sits in the cockpit jump seat and has specific things to do (set power settings, operate landing gear and flaps) as well as monitor the function of the engines. We still had engine analyzers on those old birds.
A full power run-up in the C-118 was fun. Four R-2800-52Ws at takeoff power (10,000 total hp) is impressive and very loud too.
My regards,
Widewing
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Bodhi,
I worked R2800s on DC6 aircraft for 17 years and currently work in a radial engine overhaul shop up here in Everett, WA.
The TBO for the CL-215 firebombers with the R2800-CA3 is 1300 hrs. On the DC6s we had a TBO of 2500 hrs. We had a fleet of 14 and averaged a cylinder change per day. Many R1830 users are TBO of 1200 hrs.
BeDee
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Thats cool Bedee. Bit of a different operation than ours though.... You guys must have a massive amount of spares.
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When you guys say "R2800"--is that pretty much the jug engine?, and was that the pinnacle of radial engine design?
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Referencing the DC6s, we tried to go into the spring/summer flying season with 7 QECs ready. This operation was in Alaska and we had to keep them flying especially during the fish haul. Figure 36 spark plugs per engine X 4 engines X 14 aircraft and you can see the stock of plugs we had to keep on hand alone.
BeDee
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bj229r,
Curtiss-Wright took it a step forward with the R3350 series. It was found on aircraft such as the B-29 (R3350-57AM) and on post-war aircraft such as the the Neptune and Douglas DC-7. We just put out a set of cylinders for a Douglas Skyraider (R3350-26W). Pratt & Whitney came out with the R4360 that was the pinnacle of radial engines. It had 28 cylinders in 4 rows of 7 cylinders. The Reno racer Dreadnought is using on of our engines and we are working with a museum to build some R4360s for a KC-97 restoration.
BeDee
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Took care of a DC-6 in BOS for a few months in 1984. Worked on 3 DC-3s for a small cargo outfit for a couple of years. Go out at night to do the through service with a forklift, 55gal. drum of oil, and 2 buckets of spark plugs. No sound quite as romantic as those big radials. Kind of miss it.