RC Fuels Nitromethane, Castor Oil, Synthetic, heli fuel, 4 stroke, etc...Fuel Q&A is here!

Coolpower 30% heli fuel temporally discontinued

Reply

Old 06-12-2008, 06:42 PM
  #26  
XJet
Banned
 
Join Date: Mar 2003
Location: Tokoroa, , NEW ZEALAND
Posts: 3,848
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Coolpower 30% heli fuel temporally discontinued

Why are they using mags? Why not CDI?

You can get a snot-load more joules (ie: hotter/bigger spark) out of a CDI than even a huge magneto will deliver and a CDI will be a lot lighter than a magneto to boot so that'd help the ETs.
XJet is offline  
Reply With Quote
Old 06-12-2008, 10:35 PM
  #27  
mr502go
Senior Member
 
Join Date: Jul 2007
Location: Kennesaw, GA
Posts: 111
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Coolpower 30% heli fuel temporally discontinued

even with the richer a/f ratio. . . I would bet the density in the cylinders is consierably higher. As far as force inducted engines having a "lower compression ratio" yes typically thet do. . . but you would be referring to a static compression ratio, or the total volume vs combustion chamber volume, where swept volume is part of total volume. This doesn't take into account valve events (ie when are both valves really closed, which is when the cylinder actually starts building compression) It also doesn't take into account the additional air forced into the cylinders by the power adder, in this case the supercharger. So while, yes the static ratio is very low on paper, in real life, the final compression ratio is much much higher than on most engines. Even on street cars with superchargers/nitrous oxide, it's necessary to upgrade the ignition system to deliver more joules to the plug gap, and the gap must be decreased by a significant amount just so the spark can actually jump the gap and ignite the air fuel mix. On a 5.0 liter mustang for instance, you can make 11.5:1 or so, and still maintain approximately a .050 gap and be fine, you bring the compression down to 9:1 or even 8.5:1 and add a supercharger producing 15lbs, you have to decrease the gap to approximately .035 and go colder on the heat range, to control ignition reliably. The air fuel charge still has a higher density with the blower than it would with a high compression n/a engine.
mr502go is offline  
Reply With Quote
Old 06-12-2008, 10:37 PM
  #28  
KC36330
Thread Starter
 
Join Date: Apr 2006
Location: Enterprise, AL
Posts: 5,952
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Coolpower 30% heli fuel temporally discontinued

ORIGINAL: XJet

Why are they using mags? Why not CDI?

You can get a snot-load more joules (ie: hotter/bigger spark) out of a CDI than even a huge magneto will deliver and a CDI will be a lot lighter than a magneto to boot so that'd help the ETs.
with the spark duration of 26° a CDI would have to have one hell of a capacitor to hold enough charge to give that spark duration as well as the power source to charge it back before the next firring. the mags are also driving two plugs per cylinder.
KC36330 is offline  
Reply With Quote
Old 06-13-2008, 05:06 AM
  #29  
balsaeater
Senior Member
 
Join Date: May 2005
Location: p, ANDORRA
Posts: 283
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Coolpower 30% heli fuel temporally discontinued

The drag racing world is totaly different to models and is closer to rocket motor chambers where liquid fuel and liquid oxegen are mixxed in high compression
A teasppon of fuel of which most is oxegen in the nitro methane is on each cyclinder mixxed in with high pressure air nearly liquid in the engine and hydro lock can easily blow the car cuclinder head off as there is nearly no space in the squish heads to fit the fuel and air

extract of drag racer info taken from post 45 (Balsaeater )from subject substtute nitro methane

http://www.rcuniverse.com/forum/m_66..._2/key_/tm.htm

In drag racers where they often use 85% nitro and 15% methanol sometimes higher nitro contents in the past before new rules max 85% and they generate ~6000 to ~7000 BHP plus from a 90KG V8 motor getting nearly ~80hp per one KG of motor and effectivly melting the twin 70 amp spark plugs after 4 seconds and then deiseling the motor for the remaining few seconds of the drag run
Then nitro is more of a fuel by definition of fuels and to get the extra air in they need to divert 800 hp to the Blower ( super chargers ) to cram more air in so much so that its nearly liquid air and liguid fuel in the chambers

This is more close to rocket fuel solutions and has very little resemblence to most RC modeling needs where nitro is really used to make life easier to tune RC motors so nitro is a major fuel burning component in some situations and a very very minor fuel burning component and major liquid air injection solution in other senarios like RC motors

Budget RC cars users will opt to increase compression on the motors use 5% nitro and use 20% Castor fuel to get better performance using skimmed heads or thinner or lessor no head gaskets solutions

balsaeater
balsaeater is offline  
Reply With Quote
Old 06-13-2008, 08:47 AM
  #30  
Sport_Pilot
 
Sport_Pilot's Avatar
 
Join Date: Jan 2002
Location: Acworth, GA
Posts: 16,916
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Coolpower 30% heli fuel temporally discontinued

The Mags are electronic, they may be CDI as well.
Sport_Pilot is offline  
Reply With Quote
Old 06-13-2008, 08:51 AM
  #31  
Sport_Pilot
 
Sport_Pilot's Avatar
 
Join Date: Jan 2002
Location: Acworth, GA
Posts: 16,916
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Coolpower 30% heli fuel temporally discontinued

So while, yes the static ratio is very low on paper, in real life, the final compression ratio is much much higher than on most engines.
He was talking the very real need for very low compression ratios for 100% nitro racers. This is the total compression including the supercharger. We know the other stuff you said, some don't understand the nature of nitro fuel.

On a 5.0 liter mustang for instance, you can make 11.5:1 or so, and still maintain approximately a .050 gap and be fine, you bring the compression down to 9:1 or even 8.5:1 and add a supercharger producing 15lbs,
We are talking about ratios around 6.5 here, after supercharging.

http://www.turbofast.com.au/racefuel5.html
Sport_Pilot is offline  
Reply With Quote
Old 06-13-2008, 09:10 AM
  #32  
KC36330
Thread Starter
 
Join Date: Apr 2006
Location: Enterprise, AL
Posts: 5,952
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Coolpower 30% heli fuel temporally discontinued


ORIGINAL: Sport_Pilot

The Mags are electronic, they may be CDI as well.

most of the ones i've seen in use are Mallory gear driven generator mags, they are not electronic, you dial up the timing pointer and tighten down the bolt.
KC36330 is offline  
Reply With Quote
Old 06-13-2008, 10:30 AM
  #33  
Sport_Pilot
 
Sport_Pilot's Avatar
 
Join Date: Jan 2002
Location: Acworth, GA
Posts: 16,916
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Coolpower 30% heli fuel temporally discontinued

I don't think I have seen a Mallory mag for twenty years. MSD is the formost supplier. Also timing is not that simple anymore, in fact it changes as the race is run. Not just based on speed but also some have a timer which changes the timing a set time after it starts. Also there is usually some switch's the crew chief sets for burn out and race. Recently a funny car blew its engine because they couldn't open the body to reset this switch. It failed to hit the high speed timing pattern and blew the engine. I watch nearly evey NHRA race now.

http://www.msdpromag.com/

Check out the 44 amp mag. I think many I have seen are actually bigger than this. The 12 amp mag is more like the old Mallory and Vertex mags. But even that is now elecronic pickup.

Just checked the Mallory site, they are apparently only good for 4-6 amps, not used for AA fuel dragsters.
Sport_Pilot is offline  
Reply With Quote
Old 06-13-2008, 10:44 AM
  #34  
KC36330
Thread Starter
 
Join Date: Apr 2006
Location: Enterprise, AL
Posts: 5,952
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Coolpower 30% heli fuel temporally discontinued


ORIGINAL: Sport_Pilot

Also timing is not that simple anymore, in fact it changes as the race is run. Not just based on speed but also some have a timer which changes the timing a set time after it starts.
rather then watching it on TV you might wanna actually get out the rule book and give it a good reading over, pay particular attention on ignition timing .
KC36330 is offline  
Reply With Quote
Old 06-13-2008, 12:39 PM
  #35  
Sport_Pilot
 
Sport_Pilot's Avatar
 
Join Date: Jan 2002
Location: Acworth, GA
Posts: 16,916
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Coolpower 30% heli fuel temporally discontinued

I have, I know they have some rules, but I also know what they do. The timing is advanced or retarded based on a timer, not engine RPM, or rather also. However the programing varies so often.

As of Sunday 3/19/06 all NHRA T/F Funny Cars need to send in their MSD 8971 Pro Mag Digital Retard Control units for the latest update version 9.

The PN 8971 needs to be reprogrammed to new specifications outlined below. This change will be implemented at the O’Reilly Spring National March 31-April 2.

An RMA # is Mandatory when sending your unit for the modification. Please call 915-856-2785 to obtain an RMA and shipping address. Please inform the customer service rep of the forwarding address of were to send the unit. There is a $50 fee for each unit.

On site updates will not take place, all units have to be send in for the updates.

The rate at which the engine is retarded will be set to 50 degrees per second for the first one-tenth of a second, and the remainder of the run time will be retarded at a rate of 25 degrees per second. All other variables will remain the same as Version 7. Including the time the unit is charged at 3.0 seconds, and the initial trigger rpm point of 8250.
Sport_Pilot is offline  
Reply With Quote
Old 06-13-2008, 12:59 PM
  #36  
mr502go
Senior Member
 
Join Date: Jul 2007
Location: Kennesaw, GA
Posts: 111
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Coolpower 30% heli fuel temporally discontinued

ORIGINAL: Sport_Pilot

So while, yes the static ratio is very low on paper, in real life, the final compression ratio is much much higher than on most engines.
He was talking the very real need for very low compression ratios for 100% nitro racers. This is the total compression including the supercharger. We know the other stuff you said, some don't understand the nature of nitro fuel.


We are talking about ratios around 6.5 here, after supercharging.

http://www.turbofast.com.au/racefuel5.html
Very interesting link you provided. However no where in there did it make mention between the differences of static and dynamic compression. If you maintain that with the supercharger, the maximum dynamic compression ratio will not exceed 6.5, then you would say that at full tilt, with the huge ports in the heads, and those high volume blowers, that they are only capable of filling the cylinders with 6.5 times the volume of combustion chamber in the head. I will still maintain that those compression ratios refer to static compression, which is figured only by determining mathematically the total volume (for those that don't know (swept volume + combustion chamber volume) divided by the combustion chamber volume) This doesn't take into account how much volume exits the exhaust valve (at low rpm) due to valve overlap from a huge cam, the crank can rotate quite a few degrees after bottom dead center on the intake stroke before the valve actually closes, hence the REAL swept volume is actually less (at a low rpm where air charge inertia is minimal) Static compression also doesn't take into effect how much extra air is packed in at the higher revs these cams are designed to work at, where the inertia of the air column packs more air in those few degrees of overlap, in that case there is technically a greater volume of air in the cylinder, and hence the real compression ratio will rise. There is more air per stroke @ 6000 rpm than than there is at 1000 rpm, however the chamber volume remains a constant. When you add the supercharger, or any other power adder for that matter, it simply magnifies things.

On a more important note, I think the thread has lost a bit of focus, and has turned more or less into a debate about the volatility of nitromethane, which for our purposes is really neither here nor there, though I always enjoy spririted debate =) Has anyone else looked to find any other alternatives to the coolpower 30%?? I'm considering trying to make some super thin head gaskets for some of my engines so I can get the same or better performance with less nitro.
mr502go is offline  
Reply With Quote
Old 06-13-2008, 01:43 PM
  #37  
Sport_Pilot
 
Sport_Pilot's Avatar
 
Join Date: Jan 2002
Location: Acworth, GA
Posts: 16,916
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Coolpower 30% heli fuel temporally discontinued

I still maintain that those compression ratios refer to static compression,
No, that is total. The blower doesn't actually give a big boost these days. They are only big because the engine is big.
Sport_Pilot is offline  
Reply With Quote
Old 06-13-2008, 02:27 PM
  #38  
KC36330
Thread Starter
 
Join Date: Apr 2006
Location: Enterprise, AL
Posts: 5,952
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Coolpower 30% heli fuel temporally discontinued


ORIGINAL: mr502go

............Has anyone else looked to find any other alternatives to the coolpower 30%??

the 20% Coolpower (still the Heli fuel, not the pro pattern) takes minimal tweaking of the high speed needle but it's performing only marginally less then the 30% for us, we've tested it in a few pattern ships with YS 160/170 DZ's as well as high performance heli's and the temps are in the mid to upper 90s with high humidity so it should hold over till the 30% is back in production.
KC36330 is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service