Mastertech

My Feedback: (31)

Thanks, I figured that was the case, just making sure.

Is the waiver requirement really for the operation of the engine and sub-systems or the speed of the airplane or both?

Tim

George

My Feedback: (57)

That's part of it, but it is a mechanism that allows us to operate turbine powered aircraft in a specified framework that originally was outside the AMA safety code; and allows the waiver holder to enjoy this facet of the hobby under a new set of AMA safety regs and to fall under the AMA insurance coverage.

END OF THE AMA LESSON

Anyone have other videos of the AB?[8D]

knobby1

Here's a couple of vids of my Aussie 1/4 scale dragster with one fitted, not as clean burning as the Russian effort but works pretty well nonetheless. I get ~30%, (~10lb) augmentation depending on ambient conditions....on a nice cool crisp day it really cracks.....she's damn thirsty though, the A/B by itself will drink 1200ml of fuel in less than 30 secs...[X(] The car has been clocked at 146mph during a speed meet at a drag strip.....has working chutes too..!...

http://www.youtube.com/watch?v=qk5-evHF1uA

http://www.youtube.com/watch?v=Lu-UC5afVIM


Cheers,
Smithy.

George

My Feedback: (57)

Thanks Smithy!![8D]

VF84sluggo

My Feedback: (55)

Hmmm...sounds a lot like a TF-30

Sluggo

on_your_six

My Feedback: (11)

What metals are you referring to? Titanium? Oh, I was stoked seeing this... hope he continues the effort sometime in the future.

I wish AMA was a bit more open minded about pushing the boundary limits(not just jets).. at least my dad has a farm (and mind) big enough to let me have this kind of fun.

AndyAndrews

Why would AMA care about afterburners anyway? I'm just curious. It seems to me that they are no more or less dangerous than a pulse jet engine.

Andy

Jgwright

Working model afterburners have been around for some time. There was a commercial firm in Germany making them called Skypipe but I guess that there was no commercial sales and the firm is no longer operating. They used a KJ66 size engine with an afterburner. I guess the AMA attitude did not help. I have only seen one plane fly with an afterburner once in Germany in 2004 and it was interesting but not as spectacular as you might imagine. It was a home constructed one and worked well and there were no 'flames' visible. You could hear the roar as it was switched on. Now we have such powerful engines in such light weights it removes any benefit from having them. Having said that the Russian one looks the most competant and certainly works well.

John

knobby1

No, titanium is not much good for this sort of thing, we're talking high temp stainless type materials such as Inconel, hastalloy and the like. John is correct about the "Skypipe" from several years back, I do remember seeing it.

It's actually quite difficult to get a decent burning A/B system for our small engines, we can quite easily scale down everything mechanical, but it's our inability to scale down air and fuel molecules which can cause problems, giving the fuel enough oxygen and the time to burn is where we can find problems, as can be seen in both the above examples, the tailpipe is quite a bit longer than the engine itself to allow enough time for the fuel to burn within the can. The engine itself doesn't take kindly to reverse pressures generated inside the A/B can. One has to do their homework to work out the pressure ratios and fuel burn requirements etc... They're horribly inefficient and thirsty, for a 30% increase in thrust, you use ~500% more fuel..!

When up to a decent rpm there should be very little flame visible outside the exhaust. If you've seen real jet dragsters in action, they do plenty of low rpm burns to give a nice fire show for the crowd. I try to do this when I do static shows with my little 1/4 scale dragster at my local drag strip. The "big" kids are the ones who enjoy it the most..! Me included.

Cheers,
Smithy.