I know shit I guess. I can test a top fuel engine in under 5 seconds but the
results would probably effect ticket sales.
Best
Anthony
Sent from my iPhone
On Dec 10, 2015, at 9:47 PM, Monroe L. King Jr. <monroe@xxxxxxxxxxxxxxxxxx>
wrote:
Measuring the power output of a top fuel engine directly is not always
feasible. Certain models use a torque sensor incorporated as part of the
RacePak data system. Dynamometers that can measure the output of a Top
Fuel engine exist; however, the main limitation is that a Top Fuel
engine cannot be run at its maximum power output for more than 10
seconds without overheating or possibly destroying itself explosively.
Making such high power levels from such relatively limited displacement
is a result of using very high boost levels and running at extremely
high RPMs; both of these stress the internal components to a high
degree, meaning that the peak power can only safely be achieved for
brief periods of time, and even then only by intentionally sacrificing
components. The engine power output can also be calculated based upon
the car's weight and its performance. The calculated power output of
these engines is most likely somewhere between 6,340 and 7,460 kW (8,500
and 10,000 hp),[8] which is about twice as powerful as the engines
installed on some modern diesel locomotives, and approaches the power
output of the largest aviation turboprop engine ever built, the 12,000
hp Soviet Kuznetsov NK-12 engine, with a torque output of approximately
8,100 newton metres (6,000 lbf·ft) and a brake mean effective pressure
of 8.0–10.0 MPa (1,160–1,450 psi). Of course, both locomotive diesel
and aviation turboprop engines are designed to produce these power
levels continuously for hundreds of hours without failure; one could
increase the power output of either one by many times if you were
willing to limit power output to 10 seconds or less.
For the purposes of comparison, a 2009 SSC Ultimate Aero TT, the world's
third most powerful production automobile, produces 960 kW (1,287 hp) of
power and 1,508 N·m (1,112 lbf·ft) of torque.
Engine weight
Block with liners 84.8 kg (187 lb)
Heads 18.1 kg (40 lb) each
Crankshaft 37.0 kg (81.5 lb)
Complete engine 225 kg (496 lb)
-------- Original Message --------
Subject: [AR] Re: Closing the loop on rocket engines
From: Anthony Cesaroni <acesaroni@xxxxxxxxxxx>
Date: Thu, December 10, 2015 7:33 pm
To: arocket@xxxxxxxxxxxxx
Nope. I have a test and instrumentation group and most of what they do is
design, build, commission and support dynamometer facilities for automotive
and military. For over 30 years actually. The calculation is too simple as
well as flawed. Sorry.
Anthony
Sent from my iPhone
On Dec 10, 2015, at 8:41 PM, Monroe L. King Jr. <monroe@xxxxxxxxxxxxxxxxxx>
wrote:
Sorry but you can get the HP quite easily it's a simple calculation
horsepower= weight over ET divided by 5.825
Anything under 4 seconds is in that ballpark. They actually make more HP
than that if you take into account drag and tire slippage.
-------- Original Message --------
Subject: [AR] Re: Closing the loop on rocket engines
From: Anthony Cesaroni <acesaroni@xxxxxxxxxxx>
Date: Thu, December 10, 2015 6:28 pm
To: arocket@xxxxxxxxxxxxx
No one has ever tested and verified that those engines produce that much
power. It's a hyped estimate based on flawed assumptions.
Anthony.
Sent from my iPhone
On Dec 10, 2015, at 7:59 PM, Monroe L. King Jr.
<monroe@xxxxxxxxxxxxxxxxxx> wrote:
Try out some 10,000hp action https://www.youtube.com/watch?v=CN4uAQzI1rs
Rocket guy's are cool don't get me wrong. But this is where I'm coming
from.
-------- Original Message --------
Subject: [AR] Re: Closing the loop on rocket engines
From: "Troy Prideaux" <GEORDI@xxxxxxxxxxxxxxxx>
Date: Thu, December 10, 2015 5:08 pm
To: <arocket@xxxxxxxxxxxxx>
To illustrate that last point with a comparison: let’s take the Merlin
1C or 1D combustion chamber only.
It’s small enough to fit under the bonnet of just about any car on the
road and probably light enough to be carried by a single man.
Propellants LOX:PR1 at ~2.36 O:F ratio
Feed rate: 140Kg/s (for the 1C say)
Now for that propellant combination I calculate a c* of ~1690 m/s at
optimal mixing
So, specific E Joules/Kg = (1690^2)/2 = 1430823
So incorporating flowrate 1430823 * 140 = 20,031,521 J/Kg
Converting to Power = ~20 MW
Note: that’s just the chamber only.
Now compare to a super-duper $mega sports car:
What, they max out at about 1000HP? Which is ~0.75MW?
That’s with an engine that’s substantially larger and much much heavier.
Feel free to correct any of my BOE calcs..
Troy
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx]
On Behalf Of Andrew Burns
Sent: Friday, 11 December 2015 5:17 AM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Closing the loop on rocket engines
There are several differences between rocket engines and car engines
that are key to this discussion:
- Rocket engines need only work for a few minutes at a time before being
thrown away (generally)
- Rocket engines operate with very tightly defined propellants at
controlled temperatures and pressures and within a very narrow operating
window
- Rocket engines are normally essentially binary, on or off, they're not
normally dynamically throttled
- Rocket engines have an absolutely immense thrust/power to weight ratio
compared to car engines and are accordingly so much more highly stressed