Madcow Avlanche

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Really excited to start this build. Did anyone else get a tail cone retainer with it?
 
Same here... should be here just after the weekend. Don't think I'll have it built in time for LUNAR next weekend... but soon....
 
I also got mine yesterday while I was at the SSS Spring Fest. This week we are traveling in New Mexico, so no building until next weekend.
 
What, no pics? The suspense is killing me. Any weights/is it standard wall tube/bright white or translucent, etc.....??? Won't be seeing mine 'till Wednesday at the soonest.
 
Today, I need to unpack this:
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And pack this for a week of offroading in New Mexico:
009.jpg


But I took a few minutes to unpack the much anticipated MC Avalanche:
003.jpg


004.jpg


005.jpg


006.jpg



Enjoy...
 
Per the instructions: "B. Built weight Just Over 3Lbs". No way! With hardware/epoxy/fillets/motor retainer/electronics/parachute/shock cord it's got to be more like 4.5 pounds.

Here are the weights of my kit and parts (no hardware, glue, paint, etc.):
Total: 1751g (3lb 13.7oz or 61.7oz)

Sustainer: 674g
Motor tube: 176g
AV/nose cone tube: 124g
AV outer cap: 24g ea
AV inner cap: 20g ea
Switch band: 21g
Nose cone with metal tip: 276g
Fins: 378g total
Centering rings: 10g ea

I'm building a RockSim file and will post it soon.
 
Total: 1751g

Thanks for the details, BRD. Without the avbay I'm seeing 1410g. I wonder how swatkat measured 40oz (1134g) on his kit in the other thread? The numbers in my OR file are very close to your measured weights. I'm planning to fly it SD with a chute release.

I look forward to your Rocksim file. I can't get measurements of the fins from photos very well and those weights are way off.
 
RockSim File is done. I'll post it to RocketReviews. You'll have to add your hardware, parachute, etc.
Stability is 2.33 empty.
As I stated, it's 3lb 13.7 oz for just the empty kit. And 7lb 3oz with a complete K550 motor/case. 9924 feet up with this motor, which, coincidentally, is what I bought for my L2 and will probably fly. L2 cert on the drag race is OK, right?
I ran a few sims with the model as-is. Obviously it will go lower with the extra weight that will be from all of the components.
I removed all sims that were under 50 F/s off the launch rail.
I've got anywhere from 6711 feet on a J460T up to 12795 feet on a K375NW.
I only run Aerotech for now. You can download the file and sim whatever motor you want to fly. Post your plan and the sim here.
Screenshot:
Screenshot%202018-04-10%2013.52.18.png
 
Thanks! FYI OpenRocket reports "Discontinuity in body diameter." The fincan has a diameter of 3.13" while the NC is 3.147" and switch band is 3.135". With both set to 3.13" the K335NW sims to 11813' in OpenRocket at Mach 1.17.
 
Thanks! FYI OpenRocket reports "Discontinuity in body diameter." The fincan has a diameter of 3.13" while the NC is 3.147" and switch band is 3.135". With both set to 3.13" the K335NW sims to 11813' in OpenRocket at Mach 1.17.
I put in actuals and they were definitely a little different for each component. It must suck to try to develop a new kit so I'm glad Madcow did all the hard work.
 
I put in actuals and they were definitely a little different for each component. It must suck to try to develop a new kit so I'm glad Madcow did all the hard work.

Hey is the booster tube really 33” (per you RS file)? Madcow states it’s only 30” on website.
 
Please forgive a potentially lame question. OpenRocket shows your components having fixed CGs (and masses). Did you fix the CGs intentionally, or is it a quirk of import?
 
Please forgive a potentially lame question. OpenRocket shows your components having fixed CGs (and masses). Did you fix the CGs intentionally, or is it a quirk of import?
I fixed them because they are actuals. In RockSim you can't put in just actual mass. If you override the mass it also overrides the CG. I'm not sure about how that works in OpenRocket.


BTW, there is also a RockSim file on the LDRS Avalanche Competition website (https://ldrs37.org/ldrs37-avalanche-competition/) but I doubt it is very accurate. Reported weight is 6 pounds without motor. No overrides on masses. That's why I make my own files with calipers and a scale accurate to the gram.
 
Thank you for your effort and precision. It's nice to have a good file.

Yup, BRD is correct on the weight. I don't know how I converted 1700 grams to 41 Oz. Must be my old Mars Climate Orbiter software :) Thank you for providing the file!

Rockethound, the BAR-None is supposed to arrive end of this month, so I'll get it all weighed and measured (correctly) then. But thin-walled FG and a plastic nose-cone may allow for it to slide in under 53.
 
Yup, BRD is correct on the weight. I don't know how I converted 1700 grams to 41 Oz. Must be my old Mars Climate Orbiter software :) Thank you for providing the file!

Rockethound, the BAR-None is supposed to arrive end of this month, so I'll get it all weighed and measured (correctly) then. But thin-walled FG and a plastic nose-cone may allow for it to slide in under 53.
Just a couple of questions for my learning and thought process on this setup: You are trying to keep the rocket under 53 ounces (loaded mass) so you can launch as a class one rocket, right? What motors would you use? An H242 has 110g of propellant so that's just under the 125g max for class 1. But a loaded H242 in 38/240 case is 279g (just under 10oz). Just for fun, I changed the mass of the Avalanche to 40oz to simulate the BAR-None possible mass, then loaded the H242. A simulation goes to about 2500' and is off the pad at a safe 60 F/s. And I simulated a G339N-P which has 49g propellant and weighs 190g (6.67 oz) loaded in a 38/120 case, going to just under 1000' and 73 F/s off the pad. Not bad at all. But it's plugged so you'd have to use electronics. Personally, I can't launch anywhere near my house over a few hundred feet. I'm stuck at the parks with motors up to C, maybe D in a Big Daddy kind of rocket. I'm not pushing the limits of class 1 around here (Mountain View, CA) due to the small parks and many houses. But I'm hoping the launches at Moffett Field start up again because that final sim I mentioned seems perfect with the 1000' waiver.
 
Just a couple of questions for my learning and thought process on this setup: You are trying to keep the rocket under 53 ounces (loaded mass) so you can launch as a class one rocket, right? What motors would you use? An H242 has 110g of propellant so that's just under the 125g max for class 1. But a loaded H242 in 38/240 case is 279g (just under 10oz). Just for fun, I changed the mass of the Avalanche to 40oz to simulate the BAR-None possible mass, then loaded the H242. A simulation goes to about 2500' and is off the pad at a safe 60 F/s. And I simulated a G339N-P which has 49g propellant and weighs 190g (6.67 oz) loaded in a 38/120 case, going to just under 1000' and 73 F/s off the pad. Not bad at all. But it's plugged so you'd have to use electronics. Personally, I can't launch anywhere near my house over a few hundred feet. I'm stuck at the parks with motors up to C, maybe D in a Big Daddy kind of rocket. I'm not pushing the limits of class 1 around here (Mountain View, CA) due to the small parks and many houses. But I'm hoping the launches at Moffett Field start up again because that final sim I mentioned seems perfect with the 1000' waiver.

The 53Oz limitation is for our SARG launch site. It's great, but close to McClellan AFB, so no HP waiver and a 1500' AGL limit. So we're left with kits less than 53Oz total and less than H-motors. We all also launch/are members at LUNAR where we've got HP and a 15k waiver. So love to kits that I can fly on both. Goal for the Bar-None is a nice flyer on G80-4 or G76-4 at SARG and then some mid-I power+ for LUNAR.
 
The 53Oz limitation is for our SARG launch site. It's great, but close to McClellan AFB, so no HP waiver and a 1500' AGL limit. So we're left with kits less than 53Oz total and less than H-motors. We all also launch/are members at LUNAR where we've got HP and a 15k waiver. So love to kits that I can fly on both. Goal for the Bar-None is a nice flyer on G80-4 or G76-4 at SARG and then some mid-I power+ for LUNAR.

I'm flying at LUNAR. Got a bunch of stuff for this Saturday.

On the BAR-None at 40oz rocket weight with no motor, a G76G goes to 986' and 45 F/s off the pad. I think that's passable for SARG. I would definitely go bigger on mine at LUNAR like you said. Can't wait to get these flying. Is there a BAR-None race planned for LDRS? Are you going to drag race the Avalanche?
 
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