Do I have this right? Level 1 staging motors...

SilicdyneTRF
Advertise with us
madcow rocketry
The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
mbeels

mbeels

Yes balsa
TRF Supporter
Joined
Feb 9, 2019
Messages
3,303
Reaction score
2,078
Location
SE PA
If I understand correctly, with a Level 1 HPR certification, the total impulse must be <= 640.0 Ns. So, for example, I could not fly a RMS 38mm/360 H550 ST (320.0 Ns) + I180 W (326.0 Ns) = 646.0 Ns. But I could fly DMS HP-550 ST (312 Ns) + I180 W (326.0 Ns) = 638 Ns, or even a H550 ST (320.0 Ns) + H550 ST (320.0 Ns) = 640.0 Ns.

The two things that I didn't realize are that:
1) 640.0 Ns is still Level 1 (it isn't < 640.0 as I had assumed)
2) the two H550 ST motors (RMS and DMS) have a slightly different certified impulse.

Pretty minor details, just something I thought was odd.
 
That is correct, because if the total impulse is over 640 n-s then you're into "J" territory, which is Level 2.
 
Holy Schnikeys!

A L1 certification is good up to 640 N.... :shocked: that's amazing when one realizes the LPR / MPR total impulse limit is 160 Newtons.
 
lakeroadster said:
View attachment 553054
Click to expand...


That is actually a bit misleading. What they are actually trying to point out is the difference in Class as viewed from the FAA.

Class 1 is below what is listed above. Class 2 is what is listed above. Certification level is purely the total installed impulse of the propellant in the motor, as certified/tested/designed/intended irrelevant of propellant mass.

Ignoring Research rules and average impulse, a 160ns G motor that contains KN/Sugar propellant would have a propellant mass > 125g due to its lower impulse. This means that it is a Class 2 rocket due to propellant mass in the eyes of the FAA but it is still L1 certification in the eyes of NAR/TRA (BATFE) due to the total installed impulse.
 
I think that the point of this thread is the impulse range for L1 and not a question about the hpr boundary.
 
Last edited:
Another way to look at it is myself as an L3, can go to my local chosen field that I fly rockets without an FAA waiver (Class 1). I can fly a Wildman Mach 2 on an H73J without an FAA waiver and without a formal launch because it falls under the purview of Class 1 as it's total mass is < 3.3lbm, contains < 125g of propellant, and delivers < 80ns of average impulse. It can be flown as viewed as a MPR by anyone L1 or greater certification.
 
lakeroadster said:
View attachment 553054
Click to expand...

To further clarify StreuB1's comment, the line between Aerotech's full-g motors and baby H-motors begins around 105g.

Therefore, a lightweight rocket with a baby H-motor can be a class 1 model rocket. TRA & NAR will still require a L1 cert to fly it, but the FAA has no interest in them. It's a small but confusing range of flights.
 
tsmith1315 said:
To further clarify StreuB1's comment, the line between Aerotech's full-g motors and baby H-motors begins around 105g.

Therefore, a lightweight rocket with a baby H-motor can be a class 1 model rocket. TRA & NAR will still require a L1 cert to fly it, but the FAA has no interest in them. It's a small but confusing range of flights.
Click to expand...
That is the condition I got my L1. Rocket <1500gm, Prop weight <125gm so NO FAA COA needed.
H238 at 165Ns so >160.
 
Level up man so you have more variety to deal with. Trying to stuff electronics/wiring in a small rocket is a PITA. If you want to stage, stick with tried and true BP staging to entertain yourself. Trying to work things out in a small L1 type rocket would be quite hard.
Plus, you need to get more experience with electronics first before trying APCP staging. And, you'll need a tracker of some kind. Rf (likely if a small rocket) or GPS in a larger one. Unless you don't mind losing the sustainer.
Spend your time learning deployment electronics for the time being. One small mistake and a flight could be "off-nominal".
Kurt
 
ksaves2 said:
Level up man so you have more variety to deal with. Trying to stuff electronics/wiring in a small rocket is a PITA. If you want to stage, stick with tried and true BP staging to entertain yourself. Trying to work things out in a small L1 type rocket would be quite hard.
Plus, you need to get more experience with electronics first before trying APCP staging. And, you'll need a tracker of some kind. Rf (likely if a small rocket) or GPS in a larger one. Unless you don't mind losing the sustainer.
Spend your time learning deployment electronics for the time being. One small mistake and a flight could be "off-nominal".
Kurt
Click to expand...
Basically, yes, get experience with electronic deployment first then venture into air-start multi-stage.

As for dong this with a smaller 2-stage rocket it is very doable.
Since I have been doing DD for a few years in rockets down to a BT50 (24mm) two stage air-start was next challenge.
Build a 3" from BMS school rocket kits. Launch weight is ~1000gram and been flying a G74 in booster and D15 second stage. Separation is just over 100 feet, 2-stage ignition happens around 100-150 feet. 2-stage apogee is 700-800 feet.
This completely qualifies as a non-HPR and Class 1 so can fly at local club field. Apogee is low eoung to see entire flight and also not drift out of the smallish field.
Now that I have a number of successful flights will be taking it to an MDRA launch with H to E motors (and stay within my L1 cert). This will have a GPS tracker.
 
Last edited:
ksaves2 said:
Level up man so you have more variety to deal with. Trying to stuff electronics/wiring in a small rocket is a PITA. If you want to stage, stick with tried and true BP staging to entertain yourself. Trying to work things out in a small L1 type rocket would be quite hard.
Plus, you need to get more experience with electronics first before trying APCP staging. And, you'll need a tracker of some kind. Rf (likely if a small rocket) or GPS in a larger one. Unless you don't mind losing the sustainer.
Spend your time learning deployment electronics for the time being. One small mistake and a flight could be "off-nominal".
Kurt
Click to expand...

Yes, I'll probably level up eventually, but for now I'm having a lot of fun seeing what I can do with the Level 1 constraint. The extra challenge is enjoyable to me. As my wife says, I like to make things difficult. ;)

My first full DD rocket (before HPR certification) was a 33mm MPR with a 24mm motor and I flew it quite a bit on Ds, Es, and Fs (scratch built with Eggtimer Classic). I've used GPS trackers in 38mm MD rockets (LaserLoc 163, Mach 1 Alien Interceptor), plus did some air starts which felt like a good transition to staging. Yeah, I realize that staging is a next level of complexity and potential for things to go poorly, so I'm approaching it with due respect. When I finally get there, I'll probably do a boosted-dart configuration first, and then a conservative motor combination before attempting to max out my Level 1 Ns allowance. For now it is still just ideas and simulations.

Thanks all for the input.
 
waltr said:
As for dong this with a smaller 2-stage rocket it is very doable.
Since I have been doing DD for a few years in rockets down to a BT50 (24mm) two stage air-start was next challenge.
Build a 3" from BMS school rocket kits. Launch weight is ~1000gram and been flying a G74 in booster and D15 second stage. Separation is just over 100 feet, 2-stage ignition happens around 100-150 feet. 2-stage apogee is 700-800 feet.
This completely qualifies as a non-HPR and Class 1 so can fly at local club field. Apogee is low eoung to see entire flight and also not drift out of the smallish field.
Now that I have a number of successful flights will be taking it to an MDRA launch with H to E motors (and stay within my L! cert). This will have a GPS tracker.
Click to expand...

Cool, maybe I'll see you at MDRA. I'm hoping to get out there again this winter while we're at Higgs Farm.
 
Does sound like you have the experience to build and fly a 2-stage air-start.
They are fun to watch and the next step up in challenge.

Planning MDRA at Higgs in February & March, then Red Glare.
 

mbeels​

I will be getting down to MDRA this Saturday.
Will have three rockets, one is a LOC 54mm IRIS. If there there look for it.
No 2-stage this time but very likely at the February launch.
 
waltr said:

mbeels​

I will be getting down to MDRA this Saturday.
Will have three rockets, one is a LOC 54mm IRIS. If there there look for it.
No 2-stage this time but very likely at the February launch.
Click to expand...

Hope you get some decent weather, so far the extended forecast looks quite ok. I see it is the Xmas tree launch, that should be a spectacle. I won't be able to make it down this month, but maybe February?
 
waltr said:
I will be getting down to MDRA this Saturday.
Will have three rockets, one is a LOC 54mm IRIS. If there there look for it.
No 2-stage this time but very likely at the February launch.
Click to expand...

Hello, I think I saw 2 LOC Iris rockets yesterday, one seemed to have igniter issues on the pad. I was running around a lot with my son, so I didn't catch you. How'd your launch go?
 
My IRIS (black/white 2.2") went fine and was on the first B2 pad launched. Anouncer said first HPR rocket of the day.
H128W to 2037', DD worked and landed on over side of ditch (like a lot of rockets did yesterday).
My second rocket was a LaserLOC 223 on an H250G. Went out of sight to 2858'. GPS walked me right to it.

I did talk to a lot of people and maybe even you.
 

Similar threads

INFX_TryHard
Astrorizzicist - My attempt at a mostly 3D printed L2 capable rocket
Replies
29
Views
2K
thzero
T
K
Salvage 20+Year-Old Motors ???
Replies
20
Views
1K
kjhambrick
K
J
My Wildly Overcomplicated Level 1 Build
2 3 4
Replies
93
Views
5K
Rschub
Rschub
SPStorm
LOC Precision 4" Goblin Level 1 Certification build thread
Replies
27
Views
2K
SPStorm
SPStorm
Switch
My first high power rocket for Level 1 certification: Apogee Zephyr
Replies
29
Views
6K
Peaceful_Warrior
Peaceful_Warrior

Latest posts

Back
Top