Cert 2 Max motor ?

[bobby_hamill]

Been having a chat with a friend of mine. Long story short the question is " not trying for a cert 3 what is the max motor size allowed for cert 2 use" ?

 

[dhbarr]

Most total impulse? L2200G
Longest burn time? L395
Highest average thrust? L3200
Highest peak thrust? L2525, but that curve looks funky

Physically widest motor? 98mm
Physically longest motor? Probably one of the 75mm hybrids

Fastest off the rod? Depends on the mass of your bird
Fastest top speed? Depends on the drag of your bird
Most altitude? Depends on the mass and drag of your bird

https://www.thrustcurve.org/motors/...tExempt=all&csfmApproved=all&availability=all

 

[dr wogz]

as dbharr said: define "maximum"

per "the rules", anything 'L'

 

[ThirstyBarbarian]

It’s a “maximum” L, however you define “maximum”, which is 8x more maximum than the maximum motor you have flown prior as a Level 1.

Certification is a time to show what you’ve learned and demonstrate your knowledge and skill. If you feel you have learned enough flying H and I motors to make that 8x leap to L motors, then go for it. It seems like a stretch to me.

There’s nothing in “the rules” that says you can’t do it that way, but you might have trouble getting someone to agree be a part of your certification process. No one is required to agree to being your witness, for example, and I know some L3s who definitely would decline to be associated with your cert flight, if the biggest motor you had ever flown was an I, and you wanted to fly an L for your cert flight. You should get someone on board with that plan before you get started, and make sure your club will agree to allow you to fly it. One of my clubs requires all flights over K to be submitted for approval in advance of a launch, and I’m pretty sure an L motor level 2 cert attempt would not get approved without someone going through your rocket end-to-end, and maybe not even then.

Good luck, and take a video!

 

[bobby_hamill]

Thirsty
I understand where you are coming from.I am thinking far in advance about a special project that is way down the road.

It gives me something to focus on while at home getting over my 5th hospital stay

 

[Sooner Boomer]

Getting silly playing with numbers...

L
2 K
4 J
8 I
16 H
32 G
64 F
128 E
256 D
512 C
1024 B
2048 A
4096 1/2A

Estes A10-3 (13mm) weight 8 grams ea = 16,384 grams total weight, 4 grams ea propellant = 8192 grams propellant
Estes A8-3 (18mm) weight 16 grams ea = 32,768 grams total weight, 3 grams ea propellant = 6144 grams propellant

AeroTech L339N (98mm) total weight = 3210 grams, 1796 grams propellant

AeroTech L2500ST (98mm) total weight = 4989 grams, 2313 grams propellant

Aerotech L1500T (98mm) total weight = 4658 grams, 2491 grams propellant

Just for fun, let's try to set a record, lighting off 300* C6 motors

300 C
150 D
75 E
37 F
18 G
9 H ...so you would need to be Level 1
4.5 I
2 J
K ..so you would need to be level 2

* price those in 3-packs at Hobby Lobby, *there's* a stimulus check!

 

[ThirstyBarbarian]

Thirsty
I understand where you are coming from.I am thinking far in advance about a special project that is way down the road.

It gives me something to focus on while at home getting over my 5th hospital stay

Sounds good.

Maybe I misunderstood your original question. Were you asking what is the largest motor you can use in a Level 2 certification flight? Or were you asking what is the largest motor you can fly if you are already a certified level 2? The answer is actually the same — you can fly a maximum impulse L (up to 5,120 N-s). However, one of those questions raises a red flag for me, while the other one doesn’t, and maybe I misunderstood which one you were asking. Either way, as long as it’s part of a well-planned project, that’s the important thing for motors that big.

Regarding L3 motors compared to big L2 motors, I actually often prefer watching a big L fly over watching an M because of the safety setbacks and range setups. At my clubs, the Ls can fly at the regular high-power pads, which are 300 feet away. Technically an M can launch from a pad at 500 feet, but the range is set up so that they are usually flown from an away cell that is 1,000 or more. To me, watching a big L launch from 300 feet away is more impressive than an M at 1,000 feet. I feel the same way about watching a G motor launch 30 feet away versus an H at 100 feet (or worse, 300 feet).

Good luck with your project and with your recovery! Have a healthy new year.

 

[dhbarr]

That Loki L2050 should absolutely spank a 54mm off the left side of the 50's at Airfest.. Just putting that out into the universe :-D