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How low was your level 2 certification flight

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DrewW

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For a J motor, under 1,000 feet, you might want something over 10” in diameter. Drag increases pretty quickly with increased diameter.

I’m interested in what you come up with!

I think scaling with wetted area it could be 7.5” but I have some ideas forming for increasing drag.

I think 2021 is going to be fun for me between all my rocket projects, maybe I should prepare my wife though...🤔
 
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My L2 was with a Madcow 4" Super DX3. I put almost 3 Lb of concrete .n the nose to Keep it low. We have a 3000' waver. I used a D.M.S. J270 and a chute release.
 

ThirstyBarbarian

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I think scaling with wetted area it could be 7.5” but I have some ideas forming for increasing drag.

I think 2021 is going to be fun for me between all my rocket projects, maybe I should prepare my wife though...🤔
Do you have a design in mid you are scaling?
 

DrewW

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Do you have a design in mid you are scaling?
Sorry, mental scaling off someone else’s post of a 5” rocket that I had mistaken for yours. But with drag, roughly speaking, scaling with surface area and mass scaling with volume. You could see a ~2x increase in drag and a ~3x increase in mass with a 50% upscale, all things being equal (which they seldom are)
 

Rocketjunkie

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Not a L2 cert flight, but a L2 motor to under 2000'. Could fly it without the F15's to about the same altitude.
 

AlfaBrewer

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My X-celerator (12 lbs dry) got all of 1100' on a J350 this past weekend. DD worked just as expected.
I think your sub 1k goal is quite doable with a draggy design (I'm thinking tube fin) or a heavy rocket on a high thrust-short burn motor.
 

Rocketjunkie

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None of my variable drag rockets with plates exceeded 700 feet. Dual deploy with main at 300 feet. Altitudes were 460 with 6 plates, 515 with 4, and 728 with 2 plates. The rocket will go about 2500' with just the tube fins and a J244. This would probably go as an oddroc and run afoul of the certifying authorities :)
 

RobertH3

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I was advised that keeping Cert flights low is a good thing. True.
You get to watch the entire flight and if conditions are good then a simple apogee deployment is in order. LOC Mini-Magg on J435SW-10 to 2350' with a nice roar and smoke plume to follow. DMS motor and deployment at apogee. Simple. No RMS case to lose, no altimeter or tracker to worry about. Almost ashamedly simple but textbook. Did require 0-5 mph winds and a nice sunny day.

Cheers / Robert
 

noffie79

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My L2 cert flight. Madcow PAC3 on a J285 to 2230’.

Madcow 4" PAC-3 High Power Rocket Level 2 Cert. flight w/onboard HD video
 

Tractionengines

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OK...question: is a standard tubefin (6fins with diameter equal to body tube) considered an "oddroc". I hope not. They are very stable, low flying, and what I am thinking of using for L1 and L2 if allowed....Thouhts?
 

Conway Stevens

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About 23 years ago I did my L1 cert flight to only 950ft. AT H242 in a PML 4inch Endeavor. was a perfect flight up and down on motor ejection and had a Missle works RRC altimeter on just for a measurement. Wish I had pics. night be able to find some from back then
 

T-Rex

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My soon to be Level 2 flight sims to 1672ft. We have a 2000ft ceiling, so I took a LOC Warlock and modified the fins, added a heavy parachute to achieve that goal.
Has made several flights on I motors, one of those is my avatar.
 

ThirstyBarbarian

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My soon to be Level 2 flight sims to 1672ft. We have a 2000ft ceiling, so I took a LOC Warlock and modified the fins, added a heavy parachute to achieve that goal.
Has made several flights on I motors, one of those is my avatar.
What is your fin modification?
 

DrewW

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What is your fin modification?
@T-Rex yes what is the mod? Inquiring minds want to know. Also, flying HPR on a field with a 2000’ ceiling seems pretty interesting. I’m into it, but I’m sure it limits the options significantly.
 

T-Rex

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What is your fin modification?
@T-Rex yes what is the mod? Inquiring minds want to know. Also, flying HPR on a field with a 2000’ ceiling seems pretty interesting. I’m into it, but I’m sure it limits the options significantly.
I copied and upscaled the fins from a Fat Boy. I fiddled with them a little, little bigger or little smaller, don't recall which, then made them from 1/4" ply. Anyway, with the Fat Boy fins, and pointed nose like a Big Daddy, I call it Fat Daddy.


2000ft ceiling doesn't really limit me near as much as my wallet.
 

ThirstyBarbarian

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I copied and upscaled the fins from a Fat Boy. I fiddled with them a little, little bigger or little smaller, don't recall which, then made them from 1/4" ply. Anyway, with the Fat Boy fins, and pointed nose like a Big Daddy, I call it Fat Daddy.


2000ft ceiling doesn't really limit me near as much as my wallet.
I can get a sense of it from your avatar picture, but not a lot of detail. I like the Fat Daddy name. Lol.

A 2,000 foot ceiling would not be a huge problem for me either. My L2 flight went a bit higher, but it wouldn’t have been difficult to keep it lower.
 

Arsenal78

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I did mine on a LOC 5.5 Goblin to just over 1500ft on a J425.
 

T-Rex

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I can get a sense of it from your avatar picture, but not a lot of detail. I like the Fat Daddy name. Lol.

A 2,000 foot ceiling would not be a huge problem for me either. My L2 flight went a bit higher, but it wouldn’t have been difficult to keep it lower.
I did not use the original fins. I remade them.
 

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StreuB1

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Too bad you aren't asking for Level 1.

My first L1 was only around 200 feet! LOL From liftoff to touchdown was around 20 seconds.
 

StreuB1

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A Doorknob on a J275W would be a very low an slow L2. Its huge and has loads of base drag and the J275 is barely a J and its low average thrust coupled with the drag leaves for very little post-boost coast phase.

This would also be a crowd pleaser as the J275 is also smokey and loud.
 

Idunno

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It is a challenge to do so. Low flight means tricky deployment sequence
Why would that be? I would think it is even easier. You can get away without having a drogue. Even if you use one, I don't see the difference if drogue deploys at 10,000ft vs 1000 ft.
 

dhbarr

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Why would that be? I would think it is even easier. You can get away without having a drogue. Even if you use one, I don't see the difference if drogue deploys at 10,000ft vs 1000 ft.
If you're +5 sec. ( secondary only / bonus delay / slow unfurl ) at 1k ft, it can matter a couple of shovelsful :)
 

Nytrunner

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Why would that be? I would think it is even easier. You can get away without having a drogue. Even if you use one, I don't see the difference if drogue deploys at 10,000ft vs 1000 ft.
Need a big heavy rocket to stay that low on an L2 motor. Bigger heavier rockets need bigger tanglier recovery harnesses. As dhbarr described, crap happens

Note, I didn't say it was impossible, just challenging.
 
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