Power versus Thrust

Posts from the Yahoo Groups mailing list.
Locked
rmm_guam

Power versus Thrust

Post by rmm_guam »

Hi Bruce..
Would really like to have your take on how to explain the relationship or difference between Power and Thrust.
Thanks
RMM
earthstaraircraft

Re: Power versus Thrust

Post by earthstaraircraft »

Sorry to but in but power is what the engine or motor is producing via torque and rotational speed and thrust is related to the capacity of the propellor to move air, small prop small thrust at same power,large prop large thrust same power. A Cessna 172 has 350 lb static thrust small prop, a Robinson R 22 big prop over 3000 lb of thrust. Same engine.
Happy Flying
Mark

Sent from my iPhone
jaimesadasalinas

Re: Power versus Thrust

Post by jaimesadasalinas »

Power = Thrust (F) times Velocity

P= F x V

Please note that thrust diminishes greatly with speed (Velocity) on piston
engines with propellers, as power remains practically constant

I have tested about 8 different ULs with 503, 582, HKS engines and
different props tied from the tail with a weight scale to measure static
thrust

I have gotten figures ranging from 3.5 to 4.5 lbs of thrust per nominal Hp
(Actual power ranging probably from 85% to 90% of nominal power due to
altitude, temperature, barometric pressure and humidity )

According to the attachments a C-172 should be producing around 211 Kg =
464 lbs of thrust at the altitude, temperature , barometric pressure, that
those tests were conducted

Static thrust tests <file:///Users/jim2107873540/Downloads/M0755.pdf>

Helicopter thrust must be measured under 2 very different conditions:

A.- In ground effect (HIGE)
B.- Out of ground effect (HOGE)

Those big rotors give it a much higher efficiency for take off

Say, 10-12 lbs per Hp in HOGE and 16-20 lbs per Hp of thrust for HIGE




--
The information contained in this message is being sent to the intended
recipient and contains PRIVILEGED/CONFIDENTIAL information. The
modification, retransmission, disclosure, copy or other use of such
information by persons other than the intended recipient is strictly
prohibited. If you are not the intended recipient please advise the sender
immediately by reply e-mail and delete this message and any attachments
without retaining a copy. Thank you.
dunceeconometrics

Re: Power versus Thrust

Post by dunceeconometrics »

Great example Mark! How do I get one of those Robinson props on my TGull? .....still laughing.
bruce.markle

Re: Power versus Thrust

Post by bruce.markle »

Seems to me that the early ones were called the “Laughing Gull” - Maybe they had that Robinson prop…



Sorry, just had to do it…
earthstaraircraft

Re: Power versus Thrust

Post by earthstaraircraft »

Robertson props are to expensive.
And they would hit the tail boom.
Happy Flying
Mark

Sent from my iPhone
rahulchoudhary73

Re: Power versus Thrust

Post by rahulchoudhary73 »

laughing gulls the best ever... doves and lapwings doing a major flyby here today

(saw a guy kick off a motor discussion on a physics forum, with a 100Kg magnet and 100kg of copper wire, and then what... very signifnificant discussion)
Locked