I wonder if you might get better performance from a 1/2A3T adapted down, I can’t imagine that that kind of propellant load is very well optimized in an 18mm casing.
But yes I can see how this kind of math can fall apart without too much effort.
Keeping It Low: What Approach Do You Prefer for Flying in Small Fields?
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I wonder if you might get better performance from a 1/2A3T adapted down, I can’t imagine that that kind of propellant load is very well optimized in an 18mm casing.
But yes I can see how this kind of math can fall apart without too much effort.
I'll find out about the HiFlier XL tomorrow....
D12-5. I think the C11 estimate is optimistic, however I guess that's why we light the fuse. My guess-o-meter is 597ft.
Hans.
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Does the spin induce a helical smoke trail?
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had a friend with a marriage like that. Didn’t end well…..
Not that I can tell.
Tell me about it!
shockie
High Plains Rocketeer
I locate my launch pad on the field,such it's the long direction of the field with the wind blowing in that fire tion.
I then tilt my ticket launch angle slightly into the wind.
This results in the weather cocking intentionally flying into the wind, and using a shorter time delay.
Then use streamers or smaller chutes with larger spill holes
I then tilt my ticket launch angle slightly into the wind.
This results in the weather cocking intentionally flying into the wind, and using a shorter time delay.
Then use streamers or smaller chutes with larger spill holes
Winds were light and the park was large, so I didn't keep all that many down low. And I forgot to turn the altimeter on for some flights.
Of possible interest to OP, a stock Astrocam went a whopping 72' on an A8, so even a B should keep it below 200'.
Boosted Bertha on a B6+B6 went 256', so a B+A combo might come in under 200'. This Bertha has a baffle and was carrying a JLCR as well as the altimeter, so it's a little on the heavy side.
Astron Explorer went 590’ on a D12. Extrapolating that to a C11, it's probably pretty close to OP's 200' ceiling.
My flying field elevation was about 5500’, so if you're closer to sea level, expect to get 5-10% less altitude from the thick air.
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DJRNY
well it has fins and took off like a rocket....
I'm in the same situation with smaller fields to fly in, so there is a lot of great information in this thread! I have looked at a lot of it but may have missed some things so hopefully I'm not being redundant here.
I try to choose lower impulse motors for my rockets, check the wind speed and direction, and set up appropriately in the field so as not to have them drift into the trees downwind.
I also like to fly bigger LPR models when I can. One thing I have done is use various on-line decent rate calculators to choose parachutes for my rockets to give them all similar decent rates. I usually start by launching a small rocket to a given altitude first, and if it doesn't drift too far I repeat it with a larger one. Then I will fly the smaller one higher, and repeat with a larger one, and so on. Of course I don't want to lose any rocket, but losing a small one if I push too high seems better to me than losing a large one.
Of course, there are many other factors and this is not fool proof....
I try to choose lower impulse motors for my rockets, check the wind speed and direction, and set up appropriately in the field so as not to have them drift into the trees downwind.
I also like to fly bigger LPR models when I can. One thing I have done is use various on-line decent rate calculators to choose parachutes for my rockets to give them all similar decent rates. I usually start by launching a small rocket to a given altitude first, and if it doesn't drift too far I repeat it with a larger one. Then I will fly the smaller one higher, and repeat with a larger one, and so on. Of course I don't want to lose any rocket, but losing a small one if I push too high seems better to me than losing a large one.
Of course, there are many other factors and this is not fool proof....
You can tailor your descent rate to your field type, for instance our launch fields usually have lots of grass so aren't too bad on fins. Also I think some rocket designs are more forgiving of faster landings than others. These days when I create my own designs I typically have fins set forward from the rear of the rocket so the airframe and/or motor will hit first and not the fins.
I have a theory that fin sweep priorities go something like this:
- Scratch builder: "I want to protect my fins, so I'll set them forward and/or sweep their trailing edge forward."
- Low power kit maker: "Swept fins look "rockety", plus people like rockets that will stand up on a table. If a fin breaks, that's not good, but maybe we'll get an extra sale out of it, so not all bad either."
- High power kit maker: "I don't want my rockets to have a reputation as fin-breakers, so I'll sweep the trailing edge forward. Damn, I have to offer a V2, but I sure wish people would stop buying it."
- Professional sounding rocket designers: "Swept fins are lower drag for the stability. I sure am glad I won't have to reuse them."
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I've decided that I'm just going to stick my fins straight out, with no sweep either way. Plus, that makes cutting them much easier. I'm a lazy scratch builder.
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Your next rabbit hole: rear eject. Because fixing a scratched nose cone is easier than fixing a broken fin.
I've not built any of the designs I came up with, but I fiddled with rear-eject concepts for the booster of a staged black-powder cluster a while back. Considered the application to swept fins but again didn't pursue it. Maybe someday.
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