Geek1945
Well-Known Member
To say these ratings are way over my knowledge is a gross understatement but, I know there are some who with a few clicks of their keyboard can answer this questions.
"If a jet ski engine is rated at 310HP PS >2HP/LB and produces 1890Lbs of water thrust is there a way to convert water thrust (appx) it to airscrew (propeller) thrust? Second is 1PS = 746 watts or 735.5??(1 electrical HP) since Wiki can be read either way (what's a kilopond = slug)?;
Physikalisch-Technische Bundesanstalt (PTB)[8] in Braunschweig as exactly:1 PS = 75 kilopond-meters per second(75 kp·m/s)×(9.80665 N/kp) = 735.49875 N·m/s ≈ 735.5 N·m/s ≈ 735.5 W ≈ 0.7355 kW ≈ 0.98632 hp (SAE)
The PS was adopted by the Deutsches Institut für Normung (DIN) and then by the automotive industry throughout most of Europe, under varying names. In 1992, the PS was rendered obsolete by EEC directives, when it was replaced by the kilowatt as the official power measuring unit. It is still in use for commercial and advertising purposes, in addition to the kW rating, as many customers are not familiar with the use of kilowatts for engines."
Are ASTM and SAE in agreement or are there conflicts since FAA has blessed ASTM but not SAE?
I was under the impression threads on bolts were machine cut but, NO MS bolts have rolled threads, so what's the difference? Are MS nuts threads rolled too? Are AN fittings still 37 degrees and double [upset] flared as hi-pressure fittings are?
Maybe today 746 watts = 1HP =12,000 BTU's is 100% efficiency most motors are 70 to 85% so an engine rated at 100 PS would actually be some where in 70 to 85HP? Yet, if replacing an electric motor with a engine the rule of thumb is double HP is recommended. If PS is 22 years obsolete why is it still being used. It seems these ratings have little relation to what a customer really gets. Like new car mileage stickers; your mileage will vary translated means you're dreaming you're getting less!
Life was so simple in the 1950-60's then it got screwed up using people names and smoke and mirrors advertising instead of descriptive scientific terminology. It took 2 weeks before I figured out F(x)=y then calculus got better and I wasn't the only dinosaur either. Ed
"If a jet ski engine is rated at 310HP PS >2HP/LB and produces 1890Lbs of water thrust is there a way to convert water thrust (appx) it to airscrew (propeller) thrust? Second is 1PS = 746 watts or 735.5??(1 electrical HP) since Wiki can be read either way (what's a kilopond = slug)?;
Physikalisch-Technische Bundesanstalt (PTB)[8] in Braunschweig as exactly:1 PS = 75 kilopond-meters per second(75 kp·m/s)×(9.80665 N/kp) = 735.49875 N·m/s ≈ 735.5 N·m/s ≈ 735.5 W ≈ 0.7355 kW ≈ 0.98632 hp (SAE)
The PS was adopted by the Deutsches Institut für Normung (DIN) and then by the automotive industry throughout most of Europe, under varying names. In 1992, the PS was rendered obsolete by EEC directives, when it was replaced by the kilowatt as the official power measuring unit. It is still in use for commercial and advertising purposes, in addition to the kW rating, as many customers are not familiar with the use of kilowatts for engines."
Are ASTM and SAE in agreement or are there conflicts since FAA has blessed ASTM but not SAE?
I was under the impression threads on bolts were machine cut but, NO MS bolts have rolled threads, so what's the difference? Are MS nuts threads rolled too? Are AN fittings still 37 degrees and double [upset] flared as hi-pressure fittings are?
Maybe today 746 watts = 1HP =12,000 BTU's is 100% efficiency most motors are 70 to 85% so an engine rated at 100 PS would actually be some where in 70 to 85HP? Yet, if replacing an electric motor with a engine the rule of thumb is double HP is recommended. If PS is 22 years obsolete why is it still being used. It seems these ratings have little relation to what a customer really gets. Like new car mileage stickers; your mileage will vary translated means you're dreaming you're getting less!
Life was so simple in the 1950-60's then it got screwed up using people names and smoke and mirrors advertising instead of descriptive scientific terminology. It took 2 weeks before I figured out F(x)=y then calculus got better and I wasn't the only dinosaur either. Ed
