An Interesting Graph

Just for fun, I decided to compare price to altitude for motors G through O and came up with an interesting graph. Sort of a "most bang for your buck" in a high performance sense.

For altitude I used the TRA altitude records and for motor cost I used prices from the Wildman site.

Plus, I think measuring flights in "feet per dollar" is pretty interesting. The MPG of the rocket world.



Heres the exact results:

G: 382.6 ft/$
H: 423.6 ft/$
I: 183.0 ft/$
J: 279.3 ft/$
K: 168 ft/$
L: 129.7 ft/$
M: 129.0 ft/$
N: 44 ft/$
O: 5.57 ft/$

Alex

Interesting! Thanks for posting.

Verna
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Those are interesting results. Thanks for sharing.

It would be interesting to see $/Ns plotted simultaneously, then you'd be able to see how much the actual cost factors into the cost/ft. I'd imagine poor rocket performance is tainting this data.

This is the reason I mostly fly G's and H's. Most performance per dollar by far. Personally I feel the humble little G doesn't get enough respect.

So “H” motors followed closely by “G”s gives us the most bang. . .Perhaps an inappropriate word choice considering the topic, for the buck.

Everything else falls off rapidly with each step up the alphabet.

This doesn’t even take into account the cost of building a rocket that can make maximum use of each motor.

You could probably build a $100 rocket that could get the best from a “G” whereas a $100 rocket with an “O” motor is nothing but confetti waiting to happen.

Long before I even achieved Cert 1 status I was accused of having flown an “N” motor.

One “G” at a time.

It's not surprising as it has a lot to do with rocket diameter and sectional density.

Consider that minimum diameter rockets are nominally 1", 1.3", 1.6", 2.3", 3" and 4" in diameter. The cross-sectional area aka drag increase with the square of the diameter and the square of the velocity. And if we ignore drag, mgh = 1/2 mV^2 or h = V^2 / 2g. Rockets with the same sectional density require the same impulse per unit area to reach the altitude so the larger the rocket, the more total impulse you need. The higher you go, the more velocity you need. The dependency is not close to linear and show that size and speed really add to the propellant cost.

Bob

butalane said:

I'd imagine poor rocket performance is tainting this data.

Click to expand...

Definitely. Some of those records could be broken pretty easily with the release of new motors. (I, M, O). However, that doesnt necessarily mean they'll have more ft/$. A 60k M2245 flight would be about 104.

Alex

Thanks for putting that together. For what it's worth, I've thought AT 24/40 F reloads are the most impressive performance/price I've used. There is something about a big dramatic fireball and roar of a bigger motor though.

Your graph would also appear to infer that if someone were to try and pick off a record, "I" might be the one to go for.