I bought a three pack of these along with my first reload casing. The only problem now is that I am having a difficult time identifying a rocket that can use this motor. All of my RockSim simulations show the delay to be too short. Wondering if anyone else uses this motor and what rockets they fly with it?

The only thing the E11-3J is good for is relatively light (only an 11 newton avg thrust) but draggy (large diameter) rockets that will not coast far. It is fairly limited in its usage. For example, it would work well in a Mars Lander setup with a 24mm mount.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, TURMOIL, FIASCOS, and HAVOC !

Rockets that can use low-thrust, long-burn motors tend to have long coast times and thus need long delays, but slow-burn APCP motors need delay grains that are physically very long, and the motor cases are not designed for such long grains. The result is that these slow-burn motors end up having incongruously short delays

About the only suitable birds for them are RC rocket gliders, cones and saucers, although the saucers tend to not go straight up and can still be thrusting after turning over and heading back down. That is, low-weight, high-drag birds are best suited to the low-thrust/short-delay combo, but you gotta be careful with the saucers.

The alternative is to leave out the ejection charge and instead use electronic deployment, but that adds some weight, which can be problematic with such a low thrust motor.

Doug

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YORF member #11

See my discussion on delays here.

Greg

Would it be possible to use the delay from an F12-5J with the E11? According to the Aerotech delay lengths document the delays with the F12-5J and E11-3J are the same length, but the F12-5J utilizes a slow burn material.

After further review I think my 24mm modified FatBoy should work well. I'll just have to wait for a nice calm day since the FatBoy loves to weather cock.

http://www.nar.org/SandT/pdf/Aerotech/E11.pdf

http://www.nar.org/SandT/pdf/Estes/D12.pdf

Almost anything a D12-3 can lift, the E11-3 can lift better. Peak thrust arrives earlier and stays pretty high on the E11. The D12 has slightly higher peak thrust, but it arrives later and then drops off fast.

Perfect in Maxi V-2s, Saturn Vs, etc. As always, you should use a good launch rod for fat and heavy rockets, so I suggest a 1/4" diameter by 6 foot long steel rod.

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-Fred Shecter NAR 20117 (L2)
Southern California Rocket Association, NAR Section 430

A Big Daddy would probably be good.

I've flown my Estes Big Daddy (E version, but I doubt it matters) on this motor many times. I personally think this motor is nothing short of perfect for this particular rocket.

Sandy.

You're right, Fred. I tend to think of 11N avg thrust as being low, but it's really not that low when put in the context of BP motors. However, a longer delay would still give this motor a broader range of use, IMO.

Doug

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YORF member #11

The E11J doesn't have the big spike that the D12 does, but the aggregate thrust from 0.0 to 0.5 seconds is about the same. Anything greater than 0.5 seconds the thrust is significantly greater for the E11J. As a bonus (or detriment from one's point of view) is the burn time is almost double for the E11J.

Greg

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