G-power Eliminator

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Bowhunter

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I got a new Eliminator today and I got a 24mm G37-6 I modified the mmt to allow the 7inch long motor to fit. Could someone rocsim this for me it says on the box 1400ft on a E Im just tring to find out the alt. and speed Thank You
 

slim_t

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Originally posted by Bowhunter
Im just tring to find out the alt. and speed
umm, Really high and Really fast.
Seriously, that thing gets up there on the Estes E.
I can't imagine what it'd do on a G, but I'd love to see it.

Tim
 

Zak Orion

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I looked around and couldn't find a eng file or a thrust curve for the G37, if anyone knows where it can be found please post a link. I also guessed that you were talking about the Ellis Mountain G37(been drooling ever since I heard that they were certified). With that said, I took the stats that I could find and tried to match it up as close as I could and ended up rocksimming it with a G35 Econojet(simular burntime and average impulse) and rocksim said it would go 3931ft at 558MPH. Sorry, I couldn't get the real numbers for you but this should get you in the ballpark of what the real motor will do.
 

rabidsheeep

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just a scratch idea running through my head...

if after each letter the impulse doubles then from e to f its x2, and from f to g its x4 from e, so 4 times the altitude of 1400... 5600 feet? ish?

somone correct my simple thinkings.
 

Bowhunter

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Yea its an Ellis Mountain motor I cant find the thrust cruve for it either but The epoxy is dry and just waiting for the next launch date
 

Zak Orion

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Originally posted by rabidsheeep
just a scratch idea running through my head...

if after each letter the impulse doubles then from e to f its x2, and from f to g its x4 from e, so 4 times the altitude of 1400... 5600 feet? ish?

somone correct my simple thinkings.
I am not sure if that holds up(too tired to look up the math right now). I know my Alpha Killer(stormcaster modded for a E9) does about 1500ft on a E9 but goes about 2300ft on a F21. I know a F21 is more then double the power of a E9. I would think that it has something to do with the aerodynamic forces increasing as speed increases(please tell me if I am wrong)
 

rabidsheeep

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True i guess, the faster the rocket will go the more drag will increase on anything on the rocket.
 

Bowhunter

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Originally posted by Zak Orion
[With that said, I took the stats that I could find and tried to match it up as close as I could and ended up rocksimming it with a G35 Econojet(simular burntime and average impulse) and rocksim said it would go 3931ft at 558MPH. [/B]

Wow 558 I hope the Body Tube dont collapse
 

wwattles

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It's been about 8 years since I studied quantitative aerodynamics, but I do remember that drag is an exponential function of speed combined with the coefficient of drag. In other words, as your rocket goes faster, the drag increases exponentially. Also, it means that the smoothness of your finish becomes exponentially more critical as the rocket accelerates.

Eventually you get into a variety of other issues, such as air pressure/humidity, temperature, and drag-induced friction heating. That's why on the high-power rockets that are designed to go well above Mach 1, they use high-temp materials for the nose cones.

So back to the question: doubling the power will have a decreasing effect on your altitude/speed. Yes, it will go faster and higher, but not a doubling.

WW
 

slim_t

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Originally posted by Zak Orion
my Alpha Killer(stormcaster modded for a E9) does about 1500ft on a E9 but goes about 2300ft on a F21
Zak, quick question.
How do you recover your Stormcaster? Do you use a streamer?
I built mine stock, with the exception of making room for an E. It's first launch, I used and E9 and a 12" chute, and it drifted away over the trees, and I was in a huge field. As far as I could tell, it didn't come down at all, just floated horizontally.
I've built another one since, but haven't launched it yet, and am wondering if a streamer will do the job.

Tim
 

Zak Orion

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Originally posted by slim_t
Zak, quick question.
How do you recover your Stormcaster? Do you use a streamer?
I built mine stock, with the exception of making room for an E. It's first launch, I used and E9 and a 12" chute, and it drifted away over the trees, and I was in a huge field. As far as I could tell, it didn't come down at all, just floated horizontally.
I've built another one since, but haven't launched it yet, and am wondering if a streamer will do the job.

Tim
Personally, I use a 12 inch chute(I will choke it if the wind is up). I even launched it over the winter on a F21 and got it back(second time I wasn't as lucky). I am also careful on the angle of the launch rod. I am usually lucky enough to hit it so I don't have to walk far. I also watch previous flights to see what the upper level winds are doing. The fields we have are not that big(40 acres at the small site and 160 at the big site)
 

Zak Orion

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BTW, streamer should do fine. I have found that the stormcaster is a rather strong rocket as long as you don't try landing it on a hard surface.
 

gerbs4me

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It might just shred right off the pad without glassing it.
 

fehskens

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Originally posted by wwattles
It's been about 8 years since I studied quantitative aerodynamics, but I do remember that drag is an exponential function of speed combined with the coefficient of drag.
WW
The drag is computed as

D = 1/2 * Cd * rho * A * v^2

where:
Cd is the drag coeffiecient
rho is the mass density of the medium (usually air)
A is the reference area
v is the velocity.

All in compatible units, of course.

If drag were an exponential function of velocity, the v would appear as an exponent. A mathematical nit, but an important one.

len.
 

teflonrocketry1

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I don't have the motor file for the Ellis Mountain G37 but using a Ellis Mountain G35: Maximum Altitude 4862 ft AGL, Maximum Velocity 559mph, Optimum Delay 10.5 seconds, no wind, straight up. A 6 second delay gives deployment at more than 115mph; this should shred it nicely!

Bruce S. Levison, NAR #69055
 

gerbs4me

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yep, deployment at 115mph is a shred waiting to happen.
 

Conan

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I don't think it would shred on launch, and should be OK with the right delay.

I used to fly my stock Maniac (pretty much identical to the Eliminator) on RMS F motors with the stock chute and recovered it. Of course we had a VERY large field back then...

Unfortunately I lost that Maniac to a lawn dart :(
 
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