What to Expect When You're Expecting a Cert Flight

[jqavins]

I think it would be helpful to a lot of people preparing for their first cert flights to have a description of the process. Obviously, this sis aimed at people going for L1. There are lots of folks her eon TRF better qualified than I to offer this advice, so I'm just going to get the ball rolling. I'll be happy to delete most of what I write when other people do it better.

I suggest it would be a good idea to make this thread sticky.

There is already a plethora of information here on the rocket, stuff like selecting a kit and/or designing, construction techniques and materials, motor selection, preflight checklists, etc. The focus here in on the certification process itself (but I know that some spilling over is inevitable).

Here we go.
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GENERAL

• There are certification programs in the US from both the National Association of Rocketry (NAR) and the Tripoli Rocketry Association (TRA). TRA is international, and there are also other certifying organizations in other countries (I know of Canada's and I'm sure there must be others.) The rules vary somewhat in the details, but are generally very similar.
• I recommend browsing through this thread for a lot of good advice on mistakes to avoid.
• You will build and fly a rocket that uses either an H or I motor, and recover it successfully. "Successfully" means that the deployment device (parachute, presumably) is fully deployed, the rocket is found and returned, and the rocket has either
  • Suffered no damage,
  • Suffered only cosmetic damage, or
  • Suffered minor, field repairable damage such that it could safely fly again the same day.
• Your flight and its successful result will be witnessed by a qualified person.
• Paperwork will be mailed to the certifying organization, whereupon you will receive an updated membership card, a pat on the head, a pin, a trophy, a Certificate of Achievement suitable for framing, and a solid 18 karat gold medal, or some subset of those things.

BEFORE FLIGHT DAY

• Pick a kit or design a rocket, or design modifications to a kit to be suitable for H or I motor flight. There's lots of advice on this available elsewhere on TRF (and other sources) so let's not go into it here.
• Build it well, build it strong, avoid the temptation to overbuild. Again, there's lots of information on this elsewhere.
• Consider starting a build thread here in the HPS subforum. That will give you a good place to ask questions and receive both answers and unsolicited advice which you can take or leave as you wish.

ON FLIGHT DAY

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Lunch hour is over, so I'll get back to this later unless someone beats me to it.

 

[Bat-mite]

You will need to have purchased a motor, either before flight day (recommended because them you can measure true CG), or on the field on flight day. You'll need to know what motor to choose, that has enough thrust to get good exit velocity and can hold up to the wind. You should know its descent rate, and approximately where it will come down. I have seen way too many level one certs fail because the rocketeer shot for the moon, deployed a main at apogee, and watched it sail into the sunset.

To get a motor, let the vendor know you are buying one HPR motor for a certification attempt. You cannot buy more than one until you pass.

On flight day, check in with the certifying member. The certifier must watch you build the motor, so make sure you have everything you need, like BP, dog barf, snap-ring pliers (if necessary), grease.

Once the certifier is okay with your rocket and motor, get the rocket RSOed and go to the pad. After flight, recover the rocket and present it to the certifier.

 

[waltr]

To start- go to the web site of either NAR or Tripoli (depends on which org you are to cert with) and read what they expect. NAR requires electronic filling and email address of yourself and the witness(es).
Then download the cert forms and print them.

Go through ALL the questions on the form and know how to answer each. If you don't know the answer then research to find answer and/or ask the person you found to witness the flight.

Find a person(s) with the require cert level to witness your flight and sign the forms.

It does help if you have built and flown Mid powered rockets over 1kg weight and on G motors. This helps with knowing how to setup successful recovery systems. Remember successful recovery is a cert requirement and is the most common failure to cert (it is the only thing I have seen to fail a cert).
Building a rocket to fly on a G is pretty easy.

Now on to Bat-mite's post.

 

[Donnager]

I would suggest choosing a baby H, not an H-550, not an I-500. If you can reign this in, your success likelihood will go up.

You don't need a moon shot for a certification attempt. I would suggest an H-100, H-219, or H-283 if you are using disposable Aerotech stuff.

 

[jqavins]

I would suggest choosing a baby H, not an H-550, not an I-500. If you can reign this in, your success likelihood will go up.

You don't need a moon shot for a certification attempt. I would suggest an H-100, H-219, or H-283 if you are using disposable Aerotech stuff.

Wow, it only took till the third response.

 

[Donnager]

Wow, it only took till the third response.

? I have seen too many fail, or be lost, by using hot motors for the first high power shot, especially with no deployment control. My response was #4.

Most of the college students that bring rockets to our site do their L1 with H-100's, and they tend to be successful for the most part. If you want your level 1 with a full I, or your level 2 with an L, go for it. I am just stating that if you want to certify, rather than to prove something, use the more mundane option. It's just easier.

 

[tsmith1315]

Remember that everyone involved is a volunteer.

Your certifying party is also the there to fly rockets, so expect them to be busy prepping/flying their own rockets, and oftentimes helping run the launch. Respect their time.

You'll be expected to know the certification process, so go to the appropriate TRA or NAR, CAR, etc website and study the procedure. Bring any required forms with you, and duplicates in case of wind/rain.

 

[tsmith1315]

?

There is already a plethora of information here on the rocket, stuff like selecting a kit and/or designing, construction techniques and materials, motor selection, preflight checklists, etc. The focus here in on the certification process itself

 

[Donnager]

My bad. I was just trying to give hints for how to be successful.

I guess I can't read or understand the very specific guidelines for this post.

The formality of the certification process is very specific to your Prefect or NAR representative. Trying to speculate on what someone in Kansas wants when I am familiar with Florida, Alabama, and Georgia persons, is apparently beyond my capability. I'd suggest talking to the certifying representative you have a relationship with.

 

[boatgeek]

Contact the club you're going to be flying at well in advance (say a couple of weeks) to let them know that you're hoping to fly a certification flight, what restrictions they have, if they have any advice for time to fly, and if they can help you find a witness. It is also helpful to come to a previous launch in person and fly some mid-power to see how the wind/recovery dynamics are. Most clubs are happy to help, though also respect @tsmith1315 's point that everyone is a volunteer and some of them want to fly their own rockets at the launch. You can also ask for help finding a witness on TRF if you're going to a regional or larger launch. For NAR, you will need two L1 witnesses or one L2/L3 witness for an L1 certification. Tripoli rules are likely different.

Common failure points:
Shock cord/recovery harness doesn't stay attached. This is a big one. Don't use the flimsy little eye on plastic nose cones--it will pull off at an inopportune time. Don't use screw eyes to secure your shock cord to the fin can--they will pull out. Use a threaded eye with a nut and washer (and loctite or a nylock nut) or glue the shock cord to the motor mount.

Ejection trouble. Delay is wrong, chute doesn't eject, altimeters fail. This is primarily down to experience and, if using an altimeter, ground testing before flight.

Other recovery issues. Parachute doesn't inflate, chute gets tangled, chute breaks loose, shock cord breaks. All of these are best learned with smaller rockets on lower stakes flights. Work on packing chutes so they inflate reliably, make sure your shock cord and attachments are strong enough, etc. Lots of advice on these issues on this forum. If you're using dual deployment devices (altimeter, chute release, etc.), practice with them on midpower rockets before your certification flight so you have the procedures down.

Structural issues. This is mainly going to be popping a fin on landing, or the entire rocket comes apart in flight. Use good construction techniques to keep the fins on, choose an appropriate size chute for your rocket's weight and your flying field (concrete or playa require a larger chute than soft sod). If the rocket zippers, it's usually a delay/ejection issue.

Lost rocket. It went out of sight and was never seen, drifted off in the wind, got stuck in a tree, got stuck in power lines, went into a swamp. Fly the field. Keep your altitude and descent speed in line with not losing the rocket. Advice from experienced club members will help here too. My local MPR/LPR field is nominally big enough to fly to 2000 feet or so, but flights over 1500 feet are at high risk of being lost to horse pasture, trees, or river.

And on a more meta note, you build/fly a rocket you don't like. Getting your certification isn't much good if you don't like flying afterwards. Some people do a simple cert flight on the way to a more complex/higher flying rocket. That's great if you see it as your stepping stone. If you don't, do what you love even if there's a higher risk of failure. That plays into kit selection, motor selection, etc.

 

[rharshberger]

? I have seen too many fail, or be lost, by using hot motors for the first high power shot, especially with no deployment control. My response was #4.

Most of the college students that bring rockets to our site do their L1 with H-100's, and they tend to be successful for the most part. If you want your level 1 with a full I, or your level 2 with an L, go for it. I am just stating that if you want to certify, rather than to prove something, use the more mundane option. It's just easier.

+1 we see a lot of H123W, H128W, H115, in addition to the listed motors.

 

[thzero]

All of this advice should be practiced at the midpower level. Then you L1 cert is a non-issue as you are familiar with the process, practices with the process, etc. and it should just be pack the recovery, load the motor, tech, launch, recovery, get L1 cert.

 

[jqavins]

All of this advice should be practiced at the midpower level... pack the recovery, load the motor, tech, launch, recovery, get L1 cert.

But mid power flights don't involve paperwork, official witness, buying a motor without a cert in place, etc.

 

[thzero]

But mid power flights don't involve paperwork, official witness, buying a motor without a cert in place, etc.

Best advice other than build and fly bunch of midpowers up to G? Join a NAR or TRA club! Club officers and such will be able to help with all three.

 

[Donnager]

+1 we see a lot of H123W, H128W, H115, in addition to the listed motors.

We see those as well, and they are great alternatives, as is the H135W, but usually for the non-college kids like me (I'm getting old). For some reason, the schools seem to standardize on something like a 38mm H100, which is probably a great motor for a 3" rocket that will fly to a couple thousand feet. We don't see them certify often on 29mm stuff.

It seems to work. We like having the college groups at our launches. I will say the college kids seem to have more igniter issues than what seems reasonable. I guess they figure it out. Maybe some small portion of them will be rocketeers when they get older.