Kevin Eldredge, flying Relentless in the Super Sport Class, qualified easily all week. But right before the final race on Sunday things didn't go as planned. This interview with Kevin was conducted via cell phone in his hangar. He wore his Zulu ANR headset connected to his cell phone using Bluetooth. More informatin on Zulu is available at www.LightSpeedAviation.com.
@beeroosterm - I actually reversed my notes on the first post and should have said low to medium compression engines not high compression. I think Top Fuel is 6:5:1 and the Supercharged Merlin is only 6:1.
SlamDuncDrummer 2 months ago
@beeroosterm - it is my understanding that Supercharged engines allow an engine to sustain higher power levels at rest. I.E. cruise speeds at say 1,000 less RPM etc. They also allowed piston engines to be efficient at altitude. When an engine can be at rest (so to speak) during a race, this means that this engine will have a certain period of time where it can be pushed harder.
I would think that the combination of reliability and performance would be the reasons for the Magnetos.
SlamDuncDrummer 2 months ago
@beeroosterm - I have been to a lot of top fuel events as a photographer for NHRA.com and have spent my time in between the trees and within 5 feet of the cars and I have never been sprayed with anything other than tiny tire pieces from the burn-out. Occasionally oil from an oil down but never nitro. My white lenses are typically black by the end of an event.
SlamDuncDrummer 2 months ago
@beeroosterm - I did a bit of reading and maybe you have an answer:
Nitro burns slower than gas but burns completely because it contains it's own oxygen atoms. While Nitro has lower energy density it can produce nearly 3 times more energy than gas or methanol. This is possible because Nitro contains its own oxygen atoms.
While nitro burns slower, it burns nearly 100% of the fuel. This is why you see massive header flames at night. The dual Magnetos are required to keep all that energy lit.
SlamDuncDrummer 2 months ago
@SlamDuncDrummer Turbo/supercharged engines run with low-compression pistons/combustion chambers, as the blowers up the cylinder pressures well enough. As for Top Fuel cars, they force as much fuel as possible through the cylinders - to the point that the fuel is used as a coolant as well. They do not come close to burning all the fuel that is pushed through them - as anybody who stands anywhere near them can attest. You have to take a "nitro shower" when you get home after the races.
beeroosterm 2 months ago
@beeroosterm - after doing a bit of research on this and talking to a few friends that tune Top Fuel cars and high horsepower, supercharged engines with a lot of compression on cars or aircraft, it appears that magnetos are required to get the longer duration, higher energy spark required to ignite the entire mixture.
For example; on a fuel car they are using a fuel pump that pumps 8 gallons of nitro per minute per cylinder. The magneto ignites all of this mixture leaving nothing behind.
SlamDuncDrummer 2 months ago
@SlamDuncDrummer Guess I'm a simpleton. I thought the entire point of using an electronic ignition was to eliminate the magneto/contact points setup. I've worked on them for years when restoring antique outboards, and they are a pain in the ass, with the contact points causing most of the problems.
beeroosterm 4 months ago
@beeroosterm - my simple point was that magnetos are run with electronic ignitions all the time, especially in aviation.
SlamDuncDrummer 4 months ago
@SlamDuncDrummer Here's a quote from the website "A lot of changes had been made. The wing had been moved back nine inches; a major rework of the airframe. Many other things had changed, including the moving the center of gravity, electronic ignition and tail changes." From Warbired aeropress
beeroosterm 4 months ago
@beeroosterm - on the Tsunami website and in the WIKI it clearly states that it has magnetos. Magnetos are run with electronic ignition systems all the time. In fact the WIKI states that Tsunami specifically chose magnetos for weight reduction among other reasons.
SlamDuncDrummer 4 months ago