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A question about connecting rods 2
- Thread starter dicer
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patprimmer
New member
No one has produced any data here yet. I suspect there is no back to back data in the public domain.
Most comparisons of H vs I are a racing H vs a production I so not a fair comparison.
I thought the radial engine, thread going in circles pun was an obvious joke.
I have seen a bent rod from hydraulic lock. It was a production I beam and was very bent. I have no doubt a H beam would have been equally bent so that does not really prove anything.
Re the production radials, one uses H beam for the master only and one uses I beam. Also totally non conclusive.
This really is going nowhere unless someone comes up with hard back to back data, and even then, it might depend more on the quality of the individual pieces rather than the basic I vs H design. This has all been repeated several times in this thread alone so I really have finished with it.
Regards
Pat
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Most comparisons of H vs I are a racing H vs a production I so not a fair comparison.
I thought the radial engine, thread going in circles pun was an obvious joke.
I have seen a bent rod from hydraulic lock. It was a production I beam and was very bent. I have no doubt a H beam would have been equally bent so that does not really prove anything.
Re the production radials, one uses H beam for the master only and one uses I beam. Also totally non conclusive.
This really is going nowhere unless someone comes up with hard back to back data, and even then, it might depend more on the quality of the individual pieces rather than the basic I vs H design. This has all been repeated several times in this thread alone so I really have finished with it.
Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &
for site rules
- Thread starter
- #42
The prove anything part, is the fact that a connecting rod does have a bending moment, and the excess pressure of the hydraulic lock helps prove as an exageration if you will of what is and can be happening in the cylinder as far as pressure and its effect on bending a connecting rod, a proof of forces other than just inertial effects on the rod. And shows what kind of strength is needed in high boost applications, or NOS usage in the extream, or even in those hotrod engines like top A fuel.
The usage of the two designs in the old radial engines is conclusive as we disscused why, the H was chosen.
It simply needed the cut outs to accomidate the articulated rods. It is the most effcient way to do the job and quickly, but note the articulated rods are of I beam design. The engineers most likely figured the cut outs for like the PW rod would weeken that area, and decided the H beam would sufice and be a one shot wheel cutter machining job. It was a cost cutting thing not a this is the best structure for the application thing.
Also as a side note they chose forged steel for the crankcase vs the forged aluminum that the Pratt & Whitney used. Both engine designs are exemplary, and have proven very reliable and longlasting.
The usage of the two designs in the old radial engines is conclusive as we disscused why, the H was chosen.
It simply needed the cut outs to accomidate the articulated rods. It is the most effcient way to do the job and quickly, but note the articulated rods are of I beam design. The engineers most likely figured the cut outs for like the PW rod would weeken that area, and decided the H beam would sufice and be a one shot wheel cutter machining job. It was a cost cutting thing not a this is the best structure for the application thing.
Also as a side note they chose forged steel for the crankcase vs the forged aluminum that the Pratt & Whitney used. Both engine designs are exemplary, and have proven very reliable and longlasting.
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