I've been reading about the Allison and Rolls Royce v-12 aircraft motors from WW2 in a great book called "V's For Victory!" and was wondering. Are there any modern era F1 engine manufacturers using fork and blade connecting rods? It seems there wold be some advantage to having the cylinder banks in-line with each other.
Fork and blade con rods.
Started by
Kevin Thomas
, Mar 23 2003 16:08
23 replies to this topic
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#2
CFD Dude
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Posted 23 March 2003 - 16:27
I'm not exactly sure what you mean by 'fork and blade' connecting rods. Is that where one connecting rod is 'sloted' and another fits inside of it so the cylinders in the left and right banks of a V engine don't have to be off-set from each other?
I don't know if you've seen this thread ( http://www.atlasf1.c...&threadid=49132 ) but it has some pictures a Ferrari connecting rod from the 049 engine from 2000.
I don't know if you've seen this thread ( http://www.atlasf1.c...&threadid=49132 ) but it has some pictures a Ferrari connecting rod from the 049 engine from 2000.
#3
Kevin Thomas
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Posted 23 March 2003 - 17:36
Quote
I'm not exactly sure what you mean by 'fork and blade' connecting rods. Is that where one connecting rod is 'sloted' and another fits inside of it so the cylinders in the left and right banks of a V engine don't have to be off-set from each other?
Yep. The technique was common for the Big v-12s. I just wonder if the advantages of having the cylinder banks in-line is offset by the added complexity.
#4
desmo
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Posted 23 March 2003 - 21:56
I am only familiar with the type from Harley-Davidson motorcycle engines. I think these are only suited to applications with one piece rods and built-up crankshafts. Don't see much of a potential upside other than a slight reduction in the rocking couple caused by the cylinder offset of using conventional rods. Built up cranks I expect are not up to F1 duty in any form.
#5
Kevin Thomas
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Posted 23 March 2003 - 23:35
Quote
I am only familiar with the type from Harley-Davidson motorcycle engines. I think these are only suited to applications with one piece rods and built-up crankshafts. Don't see much of a potential upside other than a slight reduction in the rocking couple caused by the cylinder offset of using conventional rods. Built up cranks I expect are not up to F1 duty in any form.
The Allison and Rolls engins used one piece crankshafts the con rods had split big-ends.
Another advantage I thought of is you would be able to reduce the length of the engine a little.
#6
marion5drsn
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Posted 23 March 2003 - 23:49
Here is a fork and blade connecting rod sketch. Used in engines from about 1900 to the Harley-Davidson motorcycle engines . Very expensive!!! Harleys also have roller bearing I believe and three piece cranks.
http://www.tpub.com/engine3/en3-51.htm
Connecting Rods: Allison bearing
Fork and blade type made from steel forgings machined and shot-peened. Connecting rod bearings consist of two flanged steel thin shells lined with nickel-silver-tin, and clamped in the forked end by two bearing caps. Center portion of the outside diameter of the bearing is covered with an overlay of nickel-silver-tin which acts as journal for the blade rod. Blade rod fits around the overlay and is held in place by a single steel cap. Bronze bearing pressed into the small end for the piston pin. Big-end bearings lubricated under pressure from crankshaft, small-end bearing lubricated by splash.
It only reduces the length of the engine by the width of one conrod if that.
M.L. Anderson
http://www.tpub.com/engine3/en3-51.htm
Connecting Rods: Allison bearing
Fork and blade type made from steel forgings machined and shot-peened. Connecting rod bearings consist of two flanged steel thin shells lined with nickel-silver-tin, and clamped in the forked end by two bearing caps. Center portion of the outside diameter of the bearing is covered with an overlay of nickel-silver-tin which acts as journal for the blade rod. Blade rod fits around the overlay and is held in place by a single steel cap. Bronze bearing pressed into the small end for the piston pin. Big-end bearings lubricated under pressure from crankshaft, small-end bearing lubricated by splash.
It only reduces the length of the engine by the width of one conrod if that.
M.L. Anderson
#7
CFD Dude
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Posted 24 March 2003 - 00:10
I have to agree with Desmo, I think they probably don't use these in F1 engine construction. With the piston speeds that they see, the strength of the connecting rod would be the main concern and more important than saving 10-15mm in the length of the engine.
On an side note, I have seen these type of connecting rods before, the Arrow advertisment in RaceCar Engineering for the last couple of months has a picture of a pair of fork and blade connecting rods.
On an side note, I have seen these type of connecting rods before, the Arrow advertisment in RaceCar Engineering for the last couple of months has a picture of a pair of fork and blade connecting rods.
#8
desmo
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Posted 24 March 2003 - 00:24
Kevin Thomas wrote:
The Allison and Rolls engines used one piece crankshafts the con rods had split big-ends.
That's interesting, I'd never seen fork and blade two piece rods. The Allison con rods actually look pretty sound.
The Allison and Rolls engines used one piece crankshafts the con rods had split big-ends.
That's interesting, I'd never seen fork and blade two piece rods. The Allison con rods actually look pretty sound.
#9
Kevin Thomas
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Posted 24 March 2003 - 02:10
Quote
Here is a fork and blade connecting rod sketch. Used in engines from about 1900 to the Harley-Davidson motorcycle engines . Very expensive!!! Harleys also have rollar bearing I believe and three piece cranks.
Cool, thanks for that. I was looking all over Google for a picture.
Looking at the picture, I guess you wouldn't save mutch in width. That thing is about as wide as two regular con rods. How much of a rocking couple would there be on a v-10?
#10
marion5drsn
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Posted 24 March 2003 - 02:45
The book,"Vees for Victory" is a real fine piece of work, read the pages about the balancing of the engines it might answer your question. I will see tomorrow just what pages it is on and will post it when I can. M.L. Anderson :yawn:
#11
Formula1_Fan
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Posted 24 March 2003 - 09:02
Take a look at the following:
The connecting rods are interlocking, blade and fork construction. The blade rod moves back and forth on the back of the upper crankpin bearing and is held in place by a counter-bore in the fork rod. See Fig. 3-2 and Fig. 3-3.
One side of the blade rod bearing surface is longer than the other and is known as the "long toe. The blade rods are installed in the right bank of the engine, with the long toe toward the center of the engine.
The fork rods are installed in the left bank of the engine. Serrations on the bottom sides of the rod match similar serrations on the bearing basket. The bearing basket consists of two halves, bolted together at the bottom by three bolts having self locking nuts. The fork rod and basket are fastened together at the serrations by means of a dowel and capscrews. Fork rods and baskets are not interchangeable since they are line bored as an assembly. Both the fork rod and basket are stamped with an identical assembly serial number for purposes of matching and identification.
The top of each rod is machined to a contour of the piston pin. Piston pins are held to the connecting rod by two capscrews, provided with non-removable spacers.
Connecting rod bearings consist of upper and lower shells, Fig. 3-2. They are semi-circular steel, having a layer of bronze covered by a lead tin coating on the inside diameter. The upper bearing also has a bearing surface in the center of the outer diameter consisting of a layer of bronze without lead tin overlay. This provides a bearing surface for the slipper of the blade connecting rod.
Dowels in the fork rod and bearing basket hold the shells in proper position. Two dowels in the fork rod hold the upper shell and the lower shell is located by a dowel in the basket.
No adjustment of connecting rod bearings is provided. When bearing clearance exceeds the limit given in the specification, replace the bearings. After bearing shells are once used on a crankpin, they must not be used on any other crankpin.
Lubricating oil is supplied the crankpin bearing from an adjacent main bearing, fed through a drilled passage in the crankshaft. An oil groove at the center of the lower bearing supplies oil to a drilled passage in the upper bearing for the blade rod bearing surface. Oil is distributed over this surface by a "fishback" or oil groove down the bearing center having grooves at right angles along its length.
The connecting rods are interlocking, blade and fork construction. The blade rod moves back and forth on the back of the upper crankpin bearing and is held in place by a counter-bore in the fork rod. See Fig. 3-2 and Fig. 3-3.
One side of the blade rod bearing surface is longer than the other and is known as the "long toe. The blade rods are installed in the right bank of the engine, with the long toe toward the center of the engine.
The fork rods are installed in the left bank of the engine. Serrations on the bottom sides of the rod match similar serrations on the bearing basket. The bearing basket consists of two halves, bolted together at the bottom by three bolts having self locking nuts. The fork rod and basket are fastened together at the serrations by means of a dowel and capscrews. Fork rods and baskets are not interchangeable since they are line bored as an assembly. Both the fork rod and basket are stamped with an identical assembly serial number for purposes of matching and identification.
The top of each rod is machined to a contour of the piston pin. Piston pins are held to the connecting rod by two capscrews, provided with non-removable spacers.
Connecting rod bearings consist of upper and lower shells, Fig. 3-2. They are semi-circular steel, having a layer of bronze covered by a lead tin coating on the inside diameter. The upper bearing also has a bearing surface in the center of the outer diameter consisting of a layer of bronze without lead tin overlay. This provides a bearing surface for the slipper of the blade connecting rod.
Dowels in the fork rod and bearing basket hold the shells in proper position. Two dowels in the fork rod hold the upper shell and the lower shell is located by a dowel in the basket.
No adjustment of connecting rod bearings is provided. When bearing clearance exceeds the limit given in the specification, replace the bearings. After bearing shells are once used on a crankpin, they must not be used on any other crankpin.
Lubricating oil is supplied the crankpin bearing from an adjacent main bearing, fed through a drilled passage in the crankshaft. An oil groove at the center of the lower bearing supplies oil to a drilled passage in the upper bearing for the blade rod bearing surface. Oil is distributed over this surface by a "fishback" or oil groove down the bearing center having grooves at right angles along its length.
#13
flannel
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Posted 24 March 2003 - 16:02
How is the blade rod pulled back down after the exhaust stroke?
#14
marion5drsn
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Posted 24 March 2003 - 18:20
Rods of any type are pulled down just like any conrod the fact that they are forked is immaterial to function!
Below is a picture from a Phantom III Rolls-Royce engine. Beautiful picture.
http://www.boddice.co.uk/bpic526.htm
How not to treat Allison conrods below!!!
http://balder.prohos...34/430-076f.jpg
http://balder.prohos...34/430-066f.jpg
Below is Mercedes-Benz WW-2 engine explaining conrod bearing.
http://usfighter.tri...om/engines3.htm
http://www.bf109.com/engine.html
Junkers Jumo V-12 engines of WW-2 had fork and blade conrods but with copper lead bearing.
Hispano-Suiza from 1914 in the 718 & 1127 cubic inch engines had fork & blade rods and probably the later V-12 aircraft engines around 1923.
Connecting Rods: Rolls-Royce Merlin
Steel I-beam connecting rods are of the fork and blade type. The forked rods operate on the "B" bank, and the blade rods on the "A" bank. All rods have separate bearing shells. The forked rod is of the "marine type" comprising an upper strut bolted to a split steel bearing block assembly in which is carried the removable-type silver-lead indium lined, steel-backed bearing shells that bear on the crankpin. The blade rod low end is fitted with a steel-backed bearing shell lined with a silver alloy, which bear directly on the forked rod bearing block.
M.L. Anderson
Below is a picture from a Phantom III Rolls-Royce engine. Beautiful picture.
http://www.boddice.co.uk/bpic526.htm
How not to treat Allison conrods below!!!
http://balder.prohos...34/430-076f.jpg
http://balder.prohos...34/430-066f.jpg
Below is Mercedes-Benz WW-2 engine explaining conrod bearing.
http://usfighter.tri...om/engines3.htm
http://www.bf109.com/engine.html
Junkers Jumo V-12 engines of WW-2 had fork and blade conrods but with copper lead bearing.
Hispano-Suiza from 1914 in the 718 & 1127 cubic inch engines had fork & blade rods and probably the later V-12 aircraft engines around 1923.
Connecting Rods: Rolls-Royce Merlin
Steel I-beam connecting rods are of the fork and blade type. The forked rods operate on the "B" bank, and the blade rods on the "A" bank. All rods have separate bearing shells. The forked rod is of the "marine type" comprising an upper strut bolted to a split steel bearing block assembly in which is carried the removable-type silver-lead indium lined, steel-backed bearing shells that bear on the crankpin. The blade rod low end is fitted with a steel-backed bearing shell lined with a silver alloy, which bear directly on the forked rod bearing block.
M.L. Anderson
#15
flannel
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Posted 25 March 2003 - 14:46
In the picture that Formula1_Fan posted, the blade type rod doesn't have a cap, so how is it pulled down, does it hook underneath the forked rod - if so, surely this is a bit gruesome!
#16
Greg Locock
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Posted 25 March 2003 - 22:08
I think it is a bit gruesome. It looks as though the blade hooks into the fork in the recess at the lower end of the square aperture.
I've got to say this is one of those areas where some enginers were chasing something that is no longer relevant - the TINY effect on block length cannot have been the primary reason to do this. The change in inertial forces and moments is also very small, in fact the increased weight of the reciprocating components may even make it worse.
I'm guessing that would have a significant effect on the main bearing loads, which may mean they could get away with a smaller crank, which would be a big weight saving.
I've got to say this is one of those areas where some enginers were chasing something that is no longer relevant - the TINY effect on block length cannot have been the primary reason to do this. The change in inertial forces and moments is also very small, in fact the increased weight of the reciprocating components may even make it worse.
I'm guessing that would have a significant effect on the main bearing loads, which may mean they could get away with a smaller crank, which would be a big weight saving.
#17
marion5drsn
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Posted 25 March 2003 - 23:28
Allison engine in a tractor below.
http://probe.prohost...m/showimage/3-3
One big thing I failed to mention is the fact that all the gear wheels, idler wheels, pinion wheels and the shafting for the overhead camshafts is equal on both of the engine possibly making the cylinder heads more interchangeable than if the engine was not "flat" on both sides. Most Vee style engines were made in this fashion up until Cadillac I believe changed to the offset banks somewhere in the late 1920s or the 1930s. I will have to do some research on this "fact". In my book on Cadillac. This is the oldest(?) Vee engine I know of! M.L. Anderson
http://www.delphion.com/details?
After writing the above I found this on the internet. Note words SIDE BY SIDE.
Le Havre, France, December 1903, the Antoinette engine, designed by Leon Levavasseur draws excitement in Aviation circles after its display. Named after the daughter of industrialist Jules Gastambide, who sponsored its development, its very lightweight and high power is believed to be the break-through needed to produce a practical powered airplane.
Also at Gastambide's expense, Levavasseur built an airplane to use the engine. However, it failed to fly during trials at Villorran near Chantilly.
This has not dampened enthusiasm for the engine. Leon Levavasseur received patents engine on August 28. Two have been perfected so far producing 24 hp and 5O hp. The larger weighs only 344 pounds. The water-cooled Antoine machined steel cylinders brass water jackets, arranged eight cylinders "V". The big ends are placed SIDE BY SIDE on four crank pins. Instead of a carburetor, a manifold pipe leads to each cylinder, through which gasoline into a tiny funnel on each cylinder. After turning the valve on, gasoline vapor and air are sucked in induction stroke. M.L. Anderson
http://probe.prohost...m/showimage/3-3
One big thing I failed to mention is the fact that all the gear wheels, idler wheels, pinion wheels and the shafting for the overhead camshafts is equal on both of the engine possibly making the cylinder heads more interchangeable than if the engine was not "flat" on both sides. Most Vee style engines were made in this fashion up until Cadillac I believe changed to the offset banks somewhere in the late 1920s or the 1930s. I will have to do some research on this "fact". In my book on Cadillac. This is the oldest(?) Vee engine I know of! M.L. Anderson
http://www.delphion.com/details?
After writing the above I found this on the internet. Note words SIDE BY SIDE.
Le Havre, France, December 1903, the Antoinette engine, designed by Leon Levavasseur draws excitement in Aviation circles after its display. Named after the daughter of industrialist Jules Gastambide, who sponsored its development, its very lightweight and high power is believed to be the break-through needed to produce a practical powered airplane.
Also at Gastambide's expense, Levavasseur built an airplane to use the engine. However, it failed to fly during trials at Villorran near Chantilly.
This has not dampened enthusiasm for the engine. Leon Levavasseur received patents engine on August 28. Two have been perfected so far producing 24 hp and 5O hp. The larger weighs only 344 pounds. The water-cooled Antoine machined steel cylinders brass water jackets, arranged eight cylinders "V". The big ends are placed SIDE BY SIDE on four crank pins. Instead of a carburetor, a manifold pipe leads to each cylinder, through which gasoline into a tiny funnel on each cylinder. After turning the valve on, gasoline vapor and air are sucked in induction stroke. M.L. Anderson
#18
desmo
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Posted 26 March 2003 - 02:13
C. F. Taylor:
"Except where there is a premium on engine length, as in aircraft, single rods side by side on a long crankpin seem the simplest and most reliable system vor V engines. Where the crankpin must be shorter, either the forked and plain system or an articulated system has proved successful."
"Except where there is a premium on engine length, as in aircraft, single rods side by side on a long crankpin seem the simplest and most reliable system vor V engines. Where the crankpin must be shorter, either the forked and plain system or an articulated system has proved successful."
#19
Greg Locock
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Posted 26 March 2003 - 23:55
Well if Taylor says it, it is hard to argue. Now I'm puzzled, why is an aircraft engine so sensitive to length?
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#20
Formula1_Fan
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Posted 27 March 2003 - 06:30
Quote
Originally posted by Greg Locock
Now I'm puzzled, why is an aircraft engine so sensitive to length?
An aircraft engine is sensitive to length, probably because it's sensitive also to volume. An aircraft engine has to be as small as possible (in external dimensions) so there will be no great effects to aerodynamics. Because of this in WW2 there were used the asteroidal engines (i don't know exactly the English term for these engines. I mean engines with a circular pattern of the cylinders), which combine big displacement->great power with low total volume of external dimensions.
#21
Greg Locock
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Posted 27 March 2003 - 12:07
I think we call them radial engines. Hmm, OK, maybe the advantage of a short engine is that you can maximise its moment about the C of G, but I really doubt that half a conrod's width (at a rough guess) is going to make or break a design. I'll go and ask some engineers.
#22
Formula1_Fan
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Posted 27 March 2003 - 21:43
Quote
Originally posted by Greg Locock
I think we call them radial engines. Hmm, OK, maybe the advantage of a short engine is that you can maximise its moment about the C of G, but I really doubt that half a conrod's width (at a rough guess) is going to make or break a design. I'll go and ask some engineers.
Apart from the shortness that you gain (ok, it's a small advantage), probably there is an issue of balance. When the cylinders are offset then there is a vibration out of that. When each cylinder has another cylinder exactly opposite then these vibrations are gone. What do you think?
#23
marion5drsn
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Posted 27 March 2003 - 22:16
Quote from Greg Locock;
I think we call them radial engines. Hmm, OK, maybe the advantage of a short engine is that you can maximize its moment about the C of G, but I really doubt that half a conrods width (at a rough guess) is going to make or break a design. I'll go and ask some engineers.
Even if you change that Center of Gravity statement to a Moment of Inertia statement what you say still applies. No one I know has up until now asked questions about the fork and blade's reason for existence and I am beginning to believe that it may be one of those things that just got started and just kept going without being re-questioned. I will make a simple sketch and see if that might answer the question.
Most, if not the vast majority of Radials were made with an odd number of cylinders due to firing problems and the cam plate problems.
M.L. Anderson
I think we call them radial engines. Hmm, OK, maybe the advantage of a short engine is that you can maximize its moment about the C of G, but I really doubt that half a conrods width (at a rough guess) is going to make or break a design. I'll go and ask some engineers.
Even if you change that Center of Gravity statement to a Moment of Inertia statement what you say still applies. No one I know has up until now asked questions about the fork and blade's reason for existence and I am beginning to believe that it may be one of those things that just got started and just kept going without being re-questioned. I will make a simple sketch and see if that might answer the question.
Most, if not the vast majority of Radials were made with an odd number of cylinders due to firing problems and the cam plate problems.
M.L. Anderson
#24
marion5drsn
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Posted 28 March 2003 - 17:25
# 1. The total length in a short stroke engine is determined by the cylinder diameter more than the conrod width and type of conrod. The offset of a side-by-side conrod setup results in the engine being the width of one conrod longer than an engine that is made with fork and blade conrods.
http://home.earthlin...BLADELENGTH.JPG
# 2. Below is the layout for the cylinders showing the offset of the right side cylinders for ONE conrod width of the cylinders in the case of this large engine it is 1.500" or 38.1mm. This being on an engine with side by side conrods.
http://home.earthlin...NGPATTERN-2.JPG
M.L. Anderson
http://home.earthlin...BLADELENGTH.JPG
# 2. Below is the layout for the cylinders showing the offset of the right side cylinders for ONE conrod width of the cylinders in the case of this large engine it is 1.500" or 38.1mm. This being on an engine with side by side conrods.
http://home.earthlin...NGPATTERN-2.JPG
M.L. Anderson
