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radial engines
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flywithastick
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advantage - sound better
disadvantage - leak a lot of oil
seriously...
advantage - dynamically they probably have an advantage (vibration, mounting issues, etc) since the length of the engine is short as compared to the number of cylinders. Shorter crank handles operating loads better & will be lighter. Multi bank radials cram a lot of cylinders in a fairly short distance (reduced bending moments at the eng mount - similar to first item).
disadvantage - lot of profile drag, oil collects in the bottom cylinders causing possible damage if not cleared when starting, a little more difficult to route exhaust manifold, plug leads, etc around the engine, round profile not quite as suited to the generally oval profile of most planes (getting weak).
disadvantage - leak a lot of oil
seriously...
advantage - dynamically they probably have an advantage (vibration, mounting issues, etc) since the length of the engine is short as compared to the number of cylinders. Shorter crank handles operating loads better & will be lighter. Multi bank radials cram a lot of cylinders in a fairly short distance (reduced bending moments at the eng mount - similar to first item).
disadvantage - lot of profile drag, oil collects in the bottom cylinders causing possible damage if not cleared when starting, a little more difficult to route exhaust manifold, plug leads, etc around the engine, round profile not quite as suited to the generally oval profile of most planes (getting weak).
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pilotyip
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Run better when damaged
I believe because they have more cylinders, they can take more internal damge and continue pumping out power, I have had to shut 4 radials in about 1000 hours of radial flying. Only one was a complete failure, in the rest the engine was still running and I made precautionary shutdowns
I believe because they have more cylinders, they can take more internal damge and continue pumping out power, I have had to shut 4 radials in about 1000 hours of radial flying. Only one was a complete failure, in the rest the engine was still running and I made precautionary shutdowns
The last season I spent in the 4Y, in four months I shut down five engines...over about a 50 hour period. Typical.
Then again, I've gone almost a hundred hours without shutting one down...once.
Radial engines have their place, but do not match turbines for power, reliability, maintenance frequency, vibration, etc.
The origional idea of the radial was to increase power in a piston engine with a minimal increase in weight, while retaining adequate cooling. The engine is short compared to an inline engine. Harmonic vibration issues created along longer crankshafts are not nearly the issue.
Someone mentioned vibration being a benifit of the radial...if you consider an increase in vibration to be a benifit, then yes, it is. Otherwise, you're stuck with a lot more airframe stress when running a radial engine. This is especially true if everything isn't running perfectly. Foul a plug, you have vibration. And so on. I've seen 3350's break their mounts, and 2600's crack of their prop governor housing assembly. I had two runaway props due to vibration breaking and shorting wires in the cannon plug to the prop governor.
Radials like to catch fire, some more than others. The 4360 seemed to like it a lot. So did the 1820, and 3350.
Radial engines are loud, and burn a lot of oil. I typically serviced each engine with 3-6 gallons of oil per flight hour.
I have lots of late-night experience changing cylinders from a ladder in the rain, being consumed by mosquitoes, and eating pizza that is wet and tastes like 60 weight oil and avgas. I also have a lot of clothing that has stains from 60 weight oil all over it.
You haven't lived until you've oiled your airplane in high winds using a 5 gallon bucket with a funnel and a ladder, and end up wearing half the bucket, and drinking the other half when you get blown off the ladder. Or burned your hands on hot exhaust stacks changing out gaskets and seals during a working day.
Radial engines are large, and heavy. With one only a couple of exceptions, they're old, and parts are no longer manufactured, but reconditioned.
With respect to piston engines, they're quite efficient in terms of what they can do for their size.
Folks will talk about how one could blow a jug and keep on flying, but those folks never owned one, or had to work on one. I've certainly never continued to operate one after it started banging; I shut them down right now. I've had jugs come off, pistons burn through, sucked valves, disintegrated superchargers and supercharger clutches, failed inductions, carburetor failures, propeller failures and governor failures, fires, etc. In each case, I shut them down, except one. In that case, I had a governor base rupture on #4 and a supercharger die on #1. I shut down the governor rupture due to excessive oil loss and a fire hazard, and kept #1. I flew to the next stop, replaced the governor base and assembly, and then departed on all four, shutting down #1 for the remainder of the flight.
The advantages are that you may be flying an airplane with radial engines, and those are what you've got. They keep you aloft.
That, and a radial engine certainly sounds better...unless you happen to live at the airport and need to get some sleep.
Radial engines do NOT take abuse well.
Radial engines are geared engines in most all cases, and demand a lot more respect. Cooling issues may be more critical in many cases, as well. Radials are not as tolerant of abusive power or operating techniques. A great deal more backlash is found in them, and these engines should be operated most all the time at power settings adequate to keep the slipstream from driving the prop. Radial engines are prone to hydraulic lock, something far less common in other types of engines, and rarely heard of in turbines
.
Then again, I've gone almost a hundred hours without shutting one down...once.
Radial engines have their place, but do not match turbines for power, reliability, maintenance frequency, vibration, etc.
The origional idea of the radial was to increase power in a piston engine with a minimal increase in weight, while retaining adequate cooling. The engine is short compared to an inline engine. Harmonic vibration issues created along longer crankshafts are not nearly the issue.
Someone mentioned vibration being a benifit of the radial...if you consider an increase in vibration to be a benifit, then yes, it is. Otherwise, you're stuck with a lot more airframe stress when running a radial engine. This is especially true if everything isn't running perfectly. Foul a plug, you have vibration. And so on. I've seen 3350's break their mounts, and 2600's crack of their prop governor housing assembly. I had two runaway props due to vibration breaking and shorting wires in the cannon plug to the prop governor.
Radials like to catch fire, some more than others. The 4360 seemed to like it a lot. So did the 1820, and 3350.
Radial engines are loud, and burn a lot of oil. I typically serviced each engine with 3-6 gallons of oil per flight hour.
I have lots of late-night experience changing cylinders from a ladder in the rain, being consumed by mosquitoes, and eating pizza that is wet and tastes like 60 weight oil and avgas. I also have a lot of clothing that has stains from 60 weight oil all over it.
You haven't lived until you've oiled your airplane in high winds using a 5 gallon bucket with a funnel and a ladder, and end up wearing half the bucket, and drinking the other half when you get blown off the ladder. Or burned your hands on hot exhaust stacks changing out gaskets and seals during a working day.
Radial engines are large, and heavy. With one only a couple of exceptions, they're old, and parts are no longer manufactured, but reconditioned.
With respect to piston engines, they're quite efficient in terms of what they can do for their size.
Folks will talk about how one could blow a jug and keep on flying, but those folks never owned one, or had to work on one. I've certainly never continued to operate one after it started banging; I shut them down right now. I've had jugs come off, pistons burn through, sucked valves, disintegrated superchargers and supercharger clutches, failed inductions, carburetor failures, propeller failures and governor failures, fires, etc. In each case, I shut them down, except one. In that case, I had a governor base rupture on #4 and a supercharger die on #1. I shut down the governor rupture due to excessive oil loss and a fire hazard, and kept #1. I flew to the next stop, replaced the governor base and assembly, and then departed on all four, shutting down #1 for the remainder of the flight.
The advantages are that you may be flying an airplane with radial engines, and those are what you've got. They keep you aloft.
That, and a radial engine certainly sounds better...unless you happen to live at the airport and need to get some sleep.
Radial engines do NOT take abuse well.
Radial engines are geared engines in most all cases, and demand a lot more respect. Cooling issues may be more critical in many cases, as well. Radials are not as tolerant of abusive power or operating techniques. A great deal more backlash is found in them, and these engines should be operated most all the time at power settings adequate to keep the slipstream from driving the prop. Radial engines are prone to hydraulic lock, something far less common in other types of engines, and rarely heard of in turbines
.
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Avbug
While certainly not first-person experience, my Dad flew Skyraiders for the Air Force during the Vietnam war. He has related many stories of guys coming home with jugs of their 3350's blown off.
I am sure the thought of shutting it down while it was still running and deep in indian country never entered their minds.
He also talked of the reliability of those engines - such as punching through a thunderstorm with rain so heavy that there was a whirlpool on the floor draining into the stick well. Never skipped a beat.
Admittedly, the modern turbine engine can't be beat but those old engines certainly did the job.
While certainly not first-person experience, my Dad flew Skyraiders for the Air Force during the Vietnam war. He has related many stories of guys coming home with jugs of their 3350's blown off.
I am sure the thought of shutting it down while it was still running and deep in indian country never entered their minds.
He also talked of the reliability of those engines - such as punching through a thunderstorm with rain so heavy that there was a whirlpool on the floor draining into the stick well. Never skipped a beat.
Admittedly, the modern turbine engine can't be beat but those old engines certainly did the job.
Triholer,
Single engine ops are a little bit different ballgame. So are military ops. If I were somewhere I didn't care to build a summer home, and blew a jug, I'd be for running it until it wouldn't run any more, too.
The heaviest rain I ever saw was in a radial powered airplane, and it didn't miss a beat (did have to adjust the carb heat, however). The rain was in Florida, and was heavy enough I couldn't see my inboard engines. I've never seen rain that bad before, or since. I do recall thinking about the thermal effect on the engine, at the time. That much water running over the cylinders, cooling them unevenly, and no cracking, no apparent adverse affects. I never did understand that. The R-2600 was a tough engine, when it was running.
It was a really tough engine, when it wasn't.
Single engine ops are a little bit different ballgame. So are military ops. If I were somewhere I didn't care to build a summer home, and blew a jug, I'd be for running it until it wouldn't run any more, too.
The heaviest rain I ever saw was in a radial powered airplane, and it didn't miss a beat (did have to adjust the carb heat, however). The rain was in Florida, and was heavy enough I couldn't see my inboard engines. I've never seen rain that bad before, or since. I do recall thinking about the thermal effect on the engine, at the time. That much water running over the cylinders, cooling them unevenly, and no cracking, no apparent adverse affects. I never did understand that. The R-2600 was a tough engine, when it was running.
It was a really tough engine, when it wasn't.
I've got about 5000 hours of being pulled thru the air by radial engines. Everything from 985's on Twin Beeches to 3350's on Connies. Had two engine shutdowns during that time. One was due to a broken crankshaft on an 1820. That one quit without warning and the prop wouldn't feather. The other shutdown was on a 3350 that had swallowed a valve. It was still producing power, but we elected to shut it down before it started making metal.
Desdamona,
TDValve touched on something important, indirectly. The way in which the engines are operated makes a very big difference. Two engine shutdowns in five thousand hours is quite remarkable for radial engines, but it makes a point. Engines which are being operated consistantly and held at constant power settings for long periods of time will surely (as a rule) outlast engines that are constantly being jockeyed with big power changes and flying at extremes.
My summer boss flies behind radials in single engine airplanes, as do many friends, and hasn't had hardly a lick of trouble. His father has spent a lifetime behind them, mostly on singles, and the same holds true.
An airplane being operated in a point to point type condition, flying from A to B with reasonably constant power settings and small changes, will most always last a whole lot longer.
Is the sound worth it? I dunno...My bike is a ricemobile because while I appreciate the "Americanness" of Harley, I can't stand the noise (can't afford the noise, either...
). The experience certainly is. You need to have an attraction to that sort of thing. If you're the sort who sees a beaver on floats and suddenly finds himself or herself short of breath with a quickened heartbeat, then certainly flying behind a radial engine is worth it. If you're wanting to push on to a job in a 737, it's probably worth it for the entertainment value...but may not necessarily be your cup of tea.
I was sitting on the ramp one morning with a senior captain, with a few moments of quiet. It was early, the sun just beginning to rise. Across the ramp I spotted a DC-3; tired, but sitting hopeful with nose in the air. I commented that I'd trade spots in a heartbeat. He looked in the general direction and commented that the Citation X there would be okay. No, I said. The Doug. The what? The Douglas. The DC-3.
Oh, he said. Hadn't even noticed it. Wouldn't have even seen it if I hadn't pointed it out. Different strokes to different folks; he saw what he wanted to see, and so did I. If you want to fly a radial powered airplane, then do so; in my opinion, you won't regret it. I love everything about a radial engine, including the times it makes you sit up and open our eyes wide, and the greasy burns from safety wire cuts and avgas while working on them. Even the oil stained clothes have a certain familiarity about which I cannot complain.
TD, I didn't get to fly the Connie. I would love to have done so, however. Some airplanes just stand out as being shapes that draw you, like the sillouette of a woman, it turns your head. The GV is that way, as is the Beech Staggerwing. Every bit as much, the Connie to me is a timeless airplane...one of these days I'd sure like to fly one.
TDValve touched on something important, indirectly. The way in which the engines are operated makes a very big difference. Two engine shutdowns in five thousand hours is quite remarkable for radial engines, but it makes a point. Engines which are being operated consistantly and held at constant power settings for long periods of time will surely (as a rule) outlast engines that are constantly being jockeyed with big power changes and flying at extremes.
My summer boss flies behind radials in single engine airplanes, as do many friends, and hasn't had hardly a lick of trouble. His father has spent a lifetime behind them, mostly on singles, and the same holds true.
An airplane being operated in a point to point type condition, flying from A to B with reasonably constant power settings and small changes, will most always last a whole lot longer.
Is the sound worth it? I dunno...My bike is a ricemobile because while I appreciate the "Americanness" of Harley, I can't stand the noise (can't afford the noise, either...
). The experience certainly is. You need to have an attraction to that sort of thing. If you're the sort who sees a beaver on floats and suddenly finds himself or herself short of breath with a quickened heartbeat, then certainly flying behind a radial engine is worth it. If you're wanting to push on to a job in a 737, it's probably worth it for the entertainment value...but may not necessarily be your cup of tea.I was sitting on the ramp one morning with a senior captain, with a few moments of quiet. It was early, the sun just beginning to rise. Across the ramp I spotted a DC-3; tired, but sitting hopeful with nose in the air. I commented that I'd trade spots in a heartbeat. He looked in the general direction and commented that the Citation X there would be okay. No, I said. The Doug. The what? The Douglas. The DC-3.
Oh, he said. Hadn't even noticed it. Wouldn't have even seen it if I hadn't pointed it out. Different strokes to different folks; he saw what he wanted to see, and so did I. If you want to fly a radial powered airplane, then do so; in my opinion, you won't regret it. I love everything about a radial engine, including the times it makes you sit up and open our eyes wide, and the greasy burns from safety wire cuts and avgas while working on them. Even the oil stained clothes have a certain familiarity about which I cannot complain.
TD, I didn't get to fly the Connie. I would love to have done so, however. Some airplanes just stand out as being shapes that draw you, like the sillouette of a woman, it turns your head. The GV is that way, as is the Beech Staggerwing. Every bit as much, the Connie to me is a timeless airplane...one of these days I'd sure like to fly one.
Avbug-
I don't even need to SEE the Beaver to be short of breath, I only need to hear it approaching! I have been known to lose large fish off the line up in Canada due to the sound of the Beaver or Otter. Alas my pocketbook will never allow ownership of such a beauty! I really just need a simple 4 seater to haul my husband around the state to meetings, but can't quite bring myself to settle for something "ordinary". So I continue to search for the perfect plane: sounds cool, has a little style, reasonable operating costs, and not costing more than my house to purchase. Any suggestions?
I don't even need to SEE the Beaver to be short of breath, I only need to hear it approaching! I have been known to lose large fish off the line up in Canada due to the sound of the Beaver or Otter. Alas my pocketbook will never allow ownership of such a beauty! I really just need a simple 4 seater to haul my husband around the state to meetings, but can't quite bring myself to settle for something "ordinary". So I continue to search for the perfect plane: sounds cool, has a little style, reasonable operating costs, and not costing more than my house to purchase. Any suggestions?
flywithastick
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Your original post didn't say anything about buying a plane.Desdamona said:
Here are a couple of ideas with lower end prices I've seen/heard of lately. I'm sure others will be able to add to the list.
450 Stearman - $90k, R985 has pretty good parts availability
220 Stearman - $70k, don't know so much about availability of these radial Lyc and Continental parts
T-6 - $90k (I know of one bought for this amount in decent flying condition), R1340 parts still pretty available
Yak-52, -55, CJ-6 - $50k & up. Popular Chinese/Russian products with pretty good parts availability. Only problem is the engine turns the wrong way!
Wilga - $45K Slow by design and engine also turns backwards.
I was pretty lucky on engine reliability for sure! There's more than one crew that had as many engine failures during a trip around the pattern as I had in ten years.
For avbug, or anyone else still flying the big radials: Does the use of 100 octane vs 115/145 have any effect on engine life? Do you still setup advance spark and 10% lean during cruise?
For avbug, or anyone else still flying the big radials: Does the use of 100 octane vs 115/145 have any effect on engine life? Do you still setup advance spark and 10% lean during cruise?
A Squared
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TD valve,
using 100LL requires us to use the CB-16 power settings on the R2800 as opposed to the CB-17 power settings (2400 BHP vs 2500 BHP) We're limited to 103,800 MGTOW rather than 107,000.
We still lean to a 12 BMEP drop in cruise (approx 10% power drop) Our spark advance systems have been deactivated. I don't know of any hard and fast figures for engine life, but theoretically running at the CB-16 settings should prolong engine life, as long as detonation is avoided.
using 100LL requires us to use the CB-16 power settings on the R2800 as opposed to the CB-17 power settings (2400 BHP vs 2500 BHP) We're limited to 103,800 MGTOW rather than 107,000.
We still lean to a 12 BMEP drop in cruise (approx 10% power drop) Our spark advance systems have been deactivated. I don't know of any hard and fast figures for engine life, but theoretically running at the CB-16 settings should prolong engine life, as long as detonation is avoided.
TD,
The spark advance is only applicable to some engines. Same for leaning. I usually used the autolean setting on the carb, as long range economy was never my primary goal. Also, it wasn't often in those airplanes that I'd stay in cruise.
100LL tends to foul plugs badly; forever chasing dying or fouled spark plugs due to leading. On the P2V-7's, the leaded fuel tended to build up on the turbine blades, too (R-3350's, J-34 on same wing).
when leaning for long cruise, I usually set up either lean or rich of peak, but usually didn't advance back to get power per the traditional method. I also leaned often by the color of the flame on the shortstacks.
The spark advance is only applicable to some engines. Same for leaning. I usually used the autolean setting on the carb, as long range economy was never my primary goal. Also, it wasn't often in those airplanes that I'd stay in cruise.
100LL tends to foul plugs badly; forever chasing dying or fouled spark plugs due to leading. On the P2V-7's, the leaded fuel tended to build up on the turbine blades, too (R-3350's, J-34 on same wing).
when leaning for long cruise, I usually set up either lean or rich of peak, but usually didn't advance back to get power per the traditional method. I also leaned often by the color of the flame on the shortstacks.
NERVOUS
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- Feb 11, 2002
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Flew the right seat on a '-6 awhile ago.
I came in one early morning into St. Domingo some time back, with that still air basically flying the ship for me. That right base to final on a visual, where the captain isn't on your case for once for not being nuts on the 'slope, and she just slid right onto the runway.
I still remember that afterglow from that greaser that warmed up that early morning cool. We taxied off to the cargo ramp passing an American Airlines jet along the way.
That heavy crew's waves were the icing on the cake. I've never felt so proud in my life before or since.
nervous
I came in one early morning into St. Domingo some time back, with that still air basically flying the ship for me. That right base to final on a visual, where the captain isn't on your case for once for not being nuts on the 'slope, and she just slid right onto the runway.
I still remember that afterglow from that greaser that warmed up that early morning cool. We taxied off to the cargo ramp passing an American Airlines jet along the way.
That heavy crew's waves were the icing on the cake. I've never felt so proud in my life before or since.
nervous
crash-proof
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Another radial fan...
My 1st consumer dream is a DC-3, 2nd plane would be an Albatross. I have this "thing" for radials, that makes me turn into a little kid and run out of meetings if i hear one outside. The sound goes straight to the heart.
I use to work by Opalocka airport couple years back, and they got this enormous assortment of radial stuff: tons of DC-3s, Super 3s, DC-6, DC-4, DC-7 (the only operational one in the world!) and lots of Convairs, not to mentions twin-beech's.
Just the other, day though, I took a spin around there and seemed like half the planes that were flyin back then were either mothballed or torn apart.
The times, they are a changin...
And from what it sounds they spend more time in the hands of a mechanic than the pilot.
My 1st consumer dream is a DC-3, 2nd plane would be an Albatross. I have this "thing" for radials, that makes me turn into a little kid and run out of meetings if i hear one outside. The sound goes straight to the heart.
I use to work by Opalocka airport couple years back, and they got this enormous assortment of radial stuff: tons of DC-3s, Super 3s, DC-6, DC-4, DC-7 (the only operational one in the world!) and lots of Convairs, not to mentions twin-beech's.
Just the other, day though, I took a spin around there and seemed like half the planes that were flyin back then were either mothballed or torn apart.
The times, they are a changin...And from what it sounds they spend more time in the hands of a mechanic than the pilot.
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