User Tag List
Results 46 to 60 of 100
-
02-21-2017, 07:45 AM #46
The point alot of people miss is it takes power to accelerate mass, that's why in a drag racing situation the lighter flywheel accelerates the boat quicker. Once the engine is up to speed it is not taking additional power to operate a heavier flywheel, but from a longevity standpoint a lighter flywheel is better, not having all the weight hanging off the top of the crankshaft, let alone what happens when the prop comes in and out of the water with the flywheel trying to twist the crankshaft
action mobile marine, 772 528 0754, dealers for aces fuel products,wolf efi, pro marine,latham and gaffrig/livorsi. we build gearcases and modify them(3 litre) to ratchet, and powerheads as well. 21 skater/3 litre wolf efi 113 mph the engine build http://www.screamandfly.com/showthre...-3-litre-build
-
02-21-2017, 08:11 AM #47Screaming And Flying!
- Join Date
- Feb 2015
- Location
- Ontario
- Posts
- 8,091
- Thanks (Given)
- 205
- Thanks (Received)
- 321
- Likes (Given)
- 1921
- Likes (Received)
- 2005
- Mentioned
- 2 Post(s)
- Tagged
- 0 Thread(s)
Take a 5hp motor with a 5 lb wheel ,run it a 4000rpm. Now replace that wheel with a 5000 lb wheel and see if it can maintain 4000rpm. Or build a flywheel which can draw mass from the outer edge toward the center while rotating.
A student stands on the center of a rotating platform that has frictionless bearings. He has a 2.0 kg object in each hand, held 1.0 m from the axis of rotation of the system. The system is initially rotating at 10 rpm. Determine a) the initial angular velocity in radians per second, b) the angular velocity of the sytem in radians per second after the objects are brought to a distance of 0.20 m from the axis of rotation, c) the change in the rotational kinetic energy of the system as the objects are pulled closer to the center of rotation. d) What causes the increase in rotational kinetic energy? (Assume that the moment of inertia of the platform + student remains constant at 1.0 kg m 2.)
Solution:
a) Use 1 rev = 2 radians and 1 minute = 60 seconds to convert:
10 rev/min = (10 rev/min )(2 rads/rev )(1 min /60 s ) = 1.05 rad /s.
b) Use conservation of angular momentum. We therefore need to compute the initial and final moments of inertia of the system:
Ii = I (student + platform) + mri2 + mri2 = 1.0 kg m 2 + (2.0 kg )(1.0 m )2 + (2.0 kg )(1.0 m )2 = 5.0 kg m 2
If = I (student + platform) + mrf2 + mrf2 = 1.0 kg m 2 + (2.0 kg )(0.2 m )2 + (2.0 kg )(0.2 m )2 = 1.16 kg m 2.
Determine final velocity using conservation of angular momentum:
So that:Ii = If.
= = x 1.05 rads/s = 4.5 rads/s.
c) The change in kinetic energy is:
KE = KEf - KEi = If - Ii = (1.16 kg m 2)(4.5 rads/s )2 - (5.0 kg m 2)(1.05 rad /s )2 = 11.8 J - 2.75 J = 9.05 J.
d) As the student pulls the object in toward the center of rotation, he is doing work on the system. This work goes into increasing the kinetic energy of the system.Last edited by FMP; 02-21-2017 at 10:05 AM.
-
02-21-2017, 10:34 AM #48
-
02-21-2017, 11:15 AM #49Screaming And Flying!
- Join Date
- Feb 2015
- Location
- Ontario
- Posts
- 8,091
- Thanks (Given)
- 205
- Thanks (Received)
- 321
- Likes (Given)
- 1921
- Likes (Received)
- 2005
- Mentioned
- 2 Post(s)
- Tagged
- 0 Thread(s)
An infinite mass wheel and an infinitely small HP will take infinite time
-
powerabout liked this post
-
02-21-2017, 03:28 PM #50Screaming And Flying!
- Join Date
- Mar 2008
- Location
- Tourist Trap, Florida
- Posts
- 14,753
- Thanks (Given)
- 381
- Thanks (Received)
- 1305
- Likes (Given)
- 5602
- Likes (Received)
- 11033
- Mentioned
- 2 Post(s)
- Tagged
- 1 Thread(s)
What I wanna know is, how do those ice skaters spin so damn fast with out a flywheel.....
83 V-King, 96 Mariner, 200 hp ff block 2.5 w/a 28p choppa
We gotta clean this liberal mess up, VOTE TRUMP TO MAGA!
Rebuild thread:
http://www.screamandfly.com/showthre...-it&highlight=
http://www.screamandfly.com/showthre...cs.&highlight=
Videos
-
02-21-2017, 03:48 PM #51
-
02-21-2017, 03:54 PM #52Screaming And Flying!
- Join Date
- Feb 2015
- Location
- Ontario
- Posts
- 8,091
- Thanks (Given)
- 205
- Thanks (Received)
- 321
- Likes (Given)
- 1921
- Likes (Received)
- 2005
- Mentioned
- 2 Post(s)
- Tagged
- 0 Thread(s)
Was going to post one with real nice shape just to give an example to the question above.
-
02-21-2017, 04:41 PM #53Screaming And Flying!
- Join Date
- Mar 2008
- Location
- Tourist Trap, Florida
- Posts
- 14,753
- Thanks (Given)
- 381
- Thanks (Received)
- 1305
- Likes (Given)
- 5602
- Likes (Received)
- 11033
- Mentioned
- 2 Post(s)
- Tagged
- 1 Thread(s)
83 V-King, 96 Mariner, 200 hp ff block 2.5 w/a 28p choppa
We gotta clean this liberal mess up, VOTE TRUMP TO MAGA!
Rebuild thread:
http://www.screamandfly.com/showthre...-it&highlight=
http://www.screamandfly.com/showthre...cs.&highlight=
Videos
-
Mr. Demeanor liked this post
-
02-21-2017, 07:36 PM #54
The hardest fact about lightened flywheels... They look cool.
If I don't ask any questions, I'll never learn anything.
-
FMP, Mr. Demeanor liked this post
-
02-21-2017, 09:02 PM #55
I know! My poor motor looks so sad. Kind of like its wearing an ugly hat.
13' Biel tunnel AKA "Flight Risk"
13" Modified Yamaha V4 - 101 mph
21' Paramount
Mercury 300 Promax
-
02-21-2017, 09:03 PM #56
-
FMP liked this post
-
02-21-2017, 09:06 PM #575000 RPM
- Join Date
- Jan 2017
- Location
- Waterford Michigan
- Posts
- 104
- Thanks (Given)
- 17
- Thanks (Received)
- 0
- Likes (Given)
- 2
- Likes (Received)
- 3
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
-
02-21-2017, 09:12 PM #585000 RPM
- Join Date
- Jan 2017
- Location
- Waterford Michigan
- Posts
- 104
- Thanks (Given)
- 17
- Thanks (Received)
- 0
- Likes (Given)
- 2
- Likes (Received)
- 3
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
-
02-21-2017, 09:16 PM #59Screaming And Flying!
- Join Date
- Feb 2015
- Location
- Ontario
- Posts
- 8,091
- Thanks (Given)
- 205
- Thanks (Received)
- 321
- Likes (Given)
- 1921
- Likes (Received)
- 2005
- Mentioned
- 2 Post(s)
- Tagged
- 0 Thread(s)
By drawing mass to center axes of rotation. Sample problems above
Last edited by FMP; 02-22-2017 at 10:45 AM.
-
msm liked this post
-
02-22-2017, 12:49 PM #60
i've been told for years n years tha lite weight came about for "slowin' down" ta turn more than any other reason.... any other benefit was jus icin'........