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-   -   Charlottesville Racers Thread (https://www.rcuniverse.com/forum/rc-regional-racers-bashers-206/2989523-charlottesville-racers-thread.html)

Big-ED 09-22-2005 07:12 AM

RE: Charlottesville Racers Thread
 
Here are the specs.
Big difference in HP..[sm=thumbup.gif]

MACH .26
Displacement: .26 cu in (4.26 cc)
Bore: 18 mm
Stroke: 16.75mm
Cylinders: ABC
RPM Range: 30,000
HP: 2.75


O.S. RG
21 RG (OSMG2055)
Engine Displacement 0.211
(cu in) Bore 0.654
(in) Stroke 0.630
(in) RPM Output 3,000-35,000
([email protected])1.9 @ 30,000
(oz)Weight 11.47
Parts Listing 13610

.

slicks 09-22-2005 07:44 AM

RE: Charlottesville Racers Thread
 
Hey ED -- wow you are here early!

I have looked at that spec's and you are correct that there is a big difference in hp -- but my thought is that there should be when comparing a .26 to a .21. My experience is that the spec's are one thing but pushing the engines hard is another. I haven't driven the Mach - but have watched Dave, Scott and Kevin kick butt with them. But last week when I was trying to stay infront of Dave (I think that it took him longer to lap me this week :)) my OS RG was hanging in there with no problems, and on the long straight was almost as fast.

I guess the fairest test would be to test them at both tracks (Scott & Wayne) as Scott's is a tighter technical track where Wayne's is more wide open with big sweepers.

Don't get me wrong -- I like my RG -- it puts out a lot of power and I can handle it because it is not too much power. It also works well at the tracks we all run at. Now Amanda is another story --she can handle the power (she kicked but when she ran Scott's 777 with the .21 Mac).


SManMTB 09-22-2005 09:56 AM

RE: Charlottesville Racers Thread
 

Hey Christian --- you are the engineer, what do you think?
Well you know, looking at the swaybardifferentiallock and the molecular balance in terms of thermal efficiency related to port volume/speed unit, I think that the bigger volume will yield a double redundancy not always needed. The larger mass and higher inertial lag combined with the viscosity change in fuel/air mixture at optimal angular speed (ω/s) will result in a definite lag in reaching max rpm (v = ω/s²). The differentiated equation for this realtionship will reach a minimum when the portliquid reaches critical mass. This happens when dφ/dt => F x sin ωt at higher centripetal forces.

A forgot to add that the power output/time area during 5 mins of racing is highly dependant on air density and running a less than optimal molecular mix will make a higher diplacement redundant and more often hurt the energy delivery more than having less volume. A small but distinct rotation of a valve assembly CW will be more beneficial than liquid displacement numbers but only up to a point where thermal expansion and stored thermal energy is smaller than the dissipation caused my fast moving objects through a viscous liquid with the same caracteristics as a mix of 20% O2 and 80% N2.

Big Stampy 09-22-2005 09:58 AM

RE: Charlottesville Racers Thread
 
Yeah, all that and it goes fast too! [sm=spinnyeyes.gif]

SManMTB 09-22-2005 10:13 AM

RE: Charlottesville Racers Thread
 
It doesn't matter what engine you have if it's not tuned properly.

slicks 09-22-2005 10:16 AM

RE: Charlottesville Racers Thread
 
so you are saying that the increase in size and weight of the Mach in a 5 minute race does not warrant the change from the RG to the Mach .26.

oh .... I think that one of your formulas is wrong.

SManMTB 09-22-2005 10:21 AM

RE: Charlottesville Racers Thread
 


ORIGINAL: slicks

so you are saying that the increase in size and weight of the Mach in a 5 minute race does not warrant the change from the RG to the Mach .26.

oh .... I think that one of your formulas is wrong.
:D They are not even wrong..... they violate all laws of thermodynamics and common sense with the power of a 80lbs rock at the speed of light.

Basically yes. But anyone who can accept a bigger rate of depletion of funds per time unit will think it's a viable substitute.

Big-ED 09-22-2005 10:41 AM

RE: Charlottesville Racers Thread
 
Yeah What Christian said..


ORIGINAL: SManMTB


Hey Christian --- you are the engineer, what do you think?
Well you know, looking at the swaybardifferentiallock and the molecular balance in terms of thermal efficiency related to port volume/speed unit, I think that the bigger volume will yield a double redundancy not always needed. The larger mass and higher inertial lag combined with the viscosity change in fuel/air mixture at optimal angular speed (ω/s) will result in a definite lag in reaching max rpm (v = ω/s²). The differentiated equation for this realtionship will reach a minimum when the portliquid reaches critical mass. This happens when dφ/dt => F x sin ωt at higher centripetal forces.

A forgot to add that the power output/time area during 5 mins of racing is highly dependant on air density and running a less than optimal molecular mix will make a higher diplacement redundant and more often hurt the energy delivery more than having less volume. A small but distinct rotation of a valve assembly CW will be more beneficial than liquid displacement numbers but only up to a point where thermal expansion and stored thermal energy is smaller than the dissipation caused my fast moving objects through a viscous liquid with the same caracteristics as a mix of 20% O2 and 80% N2.

slicks 09-22-2005 11:04 AM

RE: Charlottesville Racers Thread
 
now wait a minute ----- I'll bet that Rodney can get an 80 lb rock going at the speed of light! All he would need is a screwdriver!!!!

aahhh is it ........ depletion of funds / time ........... or is it fun / $$ :D



ok - I give - I've had enough - UNCLE - ................. what did your boss chew you out this a.m. or something!

trackman 09-22-2005 11:24 AM

RE: Charlottesville Racers Thread
 
chris i didnt feel good to start with. now i have a massive headache trying to figure out what the hell
you just said!
thats it, i quit racing. your making things entirely too difficult!!!!

SManMTB 09-22-2005 12:30 PM

RE: Charlottesville Racers Thread
 
:D:D:D:D


It was just a small amount of facts + opinions wrapped in BS.

fourwheels0 09-22-2005 12:40 PM

RE: Charlottesville Racers Thread
 
i thought it was easy to understand. oh my god my buggy is gonna fly now:D

SManMTB 09-22-2005 12:55 PM

RE: Charlottesville Racers Thread
 


ORIGINAL: slicks

now wait a minute ----- I'll bet that Rodney can get an 80 lb rock going at the speed of light! All he would need is a screwdriver!!!!

aahhh is it ........ depletion of funds / time ........... or is it fun / $$ :D



ok - I give - I've had enough - UNCLE - ................. what did your boss chew you out this a.m. or something!
I think it can be written like this:

Speed = Money / Time (Going faster means more money)
Fun = Speed x Time (Going fast a long time is more fun than going fast for 5 mins)

We can then write:

Speed = Money / Time (1)
Speed = Fun / Time (2)

Putting equation (1) and (2) equal, the equation reads:

Money / Time = Fun / Time (3)

Equation (3) can then be simplified to:

Money = Fun

:D

SManMTB 09-22-2005 12:57 PM

RE: Charlottesville Racers Thread
 


ORIGINAL: fourwheels0

i thought it was easy to understand. oh my god my buggy is gonna fly now:D
The key is the swaybardifferentiallock! [sm=thumbup.gif]

fourwheels0 09-22-2005 01:20 PM

RE: Charlottesville Racers Thread
 
i was gonna say that but i didn't want to confuse any one.

and yes critical mass=rodney+ screwdriver:D

slicks 09-22-2005 01:45 PM

RE: Charlottesville Racers Thread
 
[:@][:@][:@] AAARRRGGGHHHHH I just lost 2 1/2 hours of work! All the filters I built are GONE!!!! All of my co-workers are out of the office (including my boss) today -- so I have no one to vent to! [:@][:@]


SManMTB 09-22-2005 03:19 PM

RE: Charlottesville Racers Thread
 
PEBKAC?

Super_Dave 09-22-2005 03:22 PM

RE: Charlottesville Racers Thread
 
I belive Chris was basically saying more displacement will use more fuel giving you less runtime and there was a part in there saying that the extra weight of the internal parts and the drag of more fuel being in the motor at one time will give you less performance at a higher rpm. Well the HP and torque makes up for it.

Running at about 250 degrees I can run 6mins on a tank of fuel in 90 degree weather with about 80-90% humidity. It might be a little less run time in cold weather because in cold weather you get more air and to compensate you need to get more fuel too. Really... don't worry about run time it will last more than 5mins when its tuned right :). The mach .26 doesn't have anymore rpms than the O.S. RG but it sure as hell has more torque... that torque will let you pull a lot harder threw and out of corners and break the rear tires loose to get the buggy to steer around when you want to. The extra torque and HP also lets you gear the buggy higher giving you higher speeds. As far as value it is only $30 more than the RG but in performance its worth $50 more than the RG to me.

I never had an O.S. RG but I have broken them in and drove the one on Jesse's buggy and it just doesn't have the punch. It doesn't give you as much low end power to really pull hard out of the corners and you can't gear it for more speed like you can with the mach .26 because it just doesn't have the power.

On Scotts track its really not that big of a deal the only time I do have a slight advantage on the RG is slightly more accleration on the straight but it wasn't much at all it would really start to show about 20ft before you needed to brake but it doesn't help much there. It really helps me going up the the big double... I don't have a problem making it over where I do see some o.s. RGs if they don't hold a lot of speed through the corner and hit a smooth line then they have trouble making it over all the way. At Amherst and on Waynes track the torque helps a little more because like I said it can take a higher end gearing without losing any bottom end power. Its not even going to help you gain a half second on lap times but it should help a little and personally I feel more comfortable driving with the extra power at my fingertip.

I'll let Amanda drive my buggy next time shes at the track so she can feel the difference for herself.

octospider0 09-22-2005 03:37 PM

RE: Charlottesville Racers Thread
 
Aside from Chris's voodoo mumbo jumbo of which I am sure he is practicing black magic btw.
I am putting the machs in my buggies do to in no small part from how mine runs in the LST. There is no start problems and it will idle for damm near 5 minutes without flaming out. If it can move the mass of an LST they it has to be good in a lighter buggy.

SManMTB 09-22-2005 04:11 PM

RE: Charlottesville Racers Thread
 
OK guys, I didn't expect you to try to analyze the text. It contains BS but I did actually wrap up some 'useful' stuff in there. :)

I think Dave actually got most of it right LOL! :D:D:D
Hidden in the message, I also said that it doesn't matter how big your engine you have if you run it too rich anyway.

[sm=thumbup.gif]

Super_Dave 09-22-2005 04:32 PM

RE: Charlottesville Racers Thread
 
"A forgot to add that the power output/time area during 5 mins of racing is highly dependant on air density and running a less than optimal molecular mix will make a higher diplacement redundant and more often hurt the energy delivery more than having less volume."

That says most of it... less than optimal molecular mix: basically said running to rich is going to hurt your performance :). I can be smart when I want to be... but thats not to often :eek:. I forgot exactly what I scored highest in on an online IQ test I took but the score was 132 in some type of mathmatical area that had no math in it... just a lot of puzzles. There was no memory section to it but I'm pretty sure I would have failed that part ;).

slicks 09-22-2005 04:44 PM

RE: Charlottesville Racers Thread
 
OK - now that I am home and I had to work late today and EVEN HAD TO WEAR A TIE to a meeting (I gave up ties when I got out of manangement!) AND I lost 2 hours of work!!! I can now say that the big give away was the swaybardoohickie thingamabob that Christian first threw out there!! Good one.

Dave - your power comparisons was what I was looking for and it all makes sense.

Christian -- I hope that you wet your pants while laughing so hard!!!:D

SManMTB 09-22-2005 05:35 PM

RE: Charlottesville Racers Thread
 
I was honestly LMFAO!

slicks 09-22-2005 07:07 PM

RE: Charlottesville Racers Thread
 
So what does PEBKAC stand for?

SManMTB 09-22-2005 07:21 PM

RE: Charlottesville Racers Thread
 
Problem Exists Between Keyboard And Chair.


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