misc high power questions

hey! thinking of getting my L1 in the next while... anyways had some questions

1. how do you use your chute protectors? do you use them like wadding, where you crumple it? or do you "burrito" your parachute (or "taco" it, where the nosecone-facing half is open)? do you put a couple pieces of wadding in there along with the chute protector (to protect the chute protector,lol?)

2. how tightly should you be tightening your rail buttons? secure as hell, free flying or somewhere in the middle?

3. is a collection of nuts/screws/washers correctly assembled acceptable for L1 cert? or do you have to use a retail-style retainer for your cert?

4. if something resulted in disqualification to your L1, but your rocket is still fine to re-fly, do clubs let you re-try your L1 on the same day? i guess this would be a pretty rare scenario, but still good to know.

5. is it good to "test" your rocket on a G motor before flying? or is it better to have your L1 cert be your maiden flight? in this scenario, my "test" would be on the same day as my cert. I wouldn't be able to bring it back home and make any major changes.

thanks!

Just a few quick answers. I'm sure you'll get many more.

1. how do you use your chute protectors? do you use them like wadding, where you crumple it? or do you "burrito" your parachute (or "taco" it, where the nosecone-facing half is open)? do you put a couple pieces of wadding in there along with the chute protector (to protect the chute protector,lol?)
I use mine as a burrito. I have several with burn holes in them so I now use a handful of dog barf to help protect the protectors.

2. how tightly should you be tightening your rail buttons? secure as hell, free flying or somewhere in the middle?
I usually tighten them up snug. I think they are attached more securely that way. I do rotate them every 4 or 5 flights to even the wear.

3. is a collection of nuts/screws/washers correctly assembled acceptable for L1 cert? or do you have to use a retail-style retainer for your cert?
Yes, as long as it's positive retention.

4. if something resulted in disqualification to your L1, but your rocket is still fine to re-fly, do clubs let you re-try your L1 on the same day? i guess this would be a pretty rare scenario, but still good to know.
I'm not sure it's up the the club, I think it's up the the person signing off the cert and the organization rules.

5. is it good to "test" your rocket on a G motor before flying? or is it better to have your L1 cert be your maiden flight? in this scenario, my "test" would be on the same day as my cert. I wouldn't be able to bring it back home and make any major changes.
You can do test flights, but in your case, what would be the point? If you are doing nothing new or different with recovery or anything else and you can't make any real changes to the rocket, I would say, just fly the cert.

Good luck.

Welcome and here goes:
1. I fold my chute then completely wrap it (burrito style) in the chute protector then loosely pack the shock cord. No part of the chute is exposed to the nosecone or otherwise.
2. Open for debate. I like mine tight. Some like them loose so they can roll a bit. Loose is OK if you are prepared to replace them in case they become too loose and get lost.
3. Yes, perfectly fine.
4. You can retry as long as the rocket is in safe flying condition, even if you have to repair it to become so again.
5. Yes, you should providing the rocket you choose for your L1 can safely fly on G's. More importantly, you should want to do so because G's are fun. No test for L1 unless you count a few questions from the RSO about CG/Cp and your blood type, mothers maiden name and the number of flaps a humming bird makes with it's left wing in a minutes time.

thank you both for all your answers!

+1 to Handeman's and Grouch's comments. They nailed it, pretty good.

grouch said:

No test for L1 unless you count a few questions from the RSO about CG/Cp and your blood type, mothers maiden name and the number of flaps a humming bird makes with it's left wing in a minutes time.

Click to expand...

Due to the fact a hummingbird flaps both of its wings at the same time, and a hummingbird can flap up to 70 times per second, that would be approximately 4200 times.

Was that a laden or unladen hummingbird?

Of course, you can always install a baffle to your HPR to mitigate the need for the burrito.

I learned yesterday that you can also protect your shock cord with a Nomex sleeve for the edges closest to the flame.

You might want to check out my Raptor Evolution build (and look over the .ork file and .rkt files found there) for ideas on baffles.

Regarding your 2nd question. I like mine to be able to spin. It's my preference... YMMV

As to your 4th question: It's not as rare as you might think. I got my L1 yesterday. My first attempt (using an H178DM-14A Metalstorm DM) resulted in a busted nosecone. It was (with help from Salvage1) duct taped it back together, and flew less than an hour later with an I357T-14A Blue Thunder successfully. As my rocket was able to be repaired and flown again on the same day, I'm now certified as a NAR L1 flier through OROC.

To Question 5: My rocket was a scratch built rocket without any prior flights. I felt it was due diligence to fly it on an G-67R Redline just to make sure it was safe. Building a known kit (or mod of one (e.g.: MDRM)) that has been demonstrated repeatedly for successful L1 attempts might not need that confidence booster (but it's still a good idea to give it a test flight).


Pointy Side Up!
Jim

You can tape the motor in if you want. (positive retention is NOT required.)

I crank my buttons down. if they wear out, I'll replace them. 8 foot of derlin on alum is not going to cause enough drag for me to give a whoop about.

I look at test flights like this: Why? there's zero reason. You're putting the rocket at risk on a likely underpowered motor, for what? to see if it's stable? you know it's stable. That it will fly? You better know it'll fly. That the recovery works? It's a cord and a parachute. There is no penalty for a failed L1. So, why test fly? Fly on the L1 motor. if you succeed...win! if you succeed on a G, you just put a flight of wear on the rocket, risked damage, and still no cert.

I say put an I600 in it and punch it.

blackbrandt said:

Due to the fact a hummingbird flaps both of its wings at the same time, and a hummingbird can flap up to 70 times per second, that would be approximately 4200 times.

Click to expand...

Oh young BB, college may be trying times for you. You are assuming said humming bird is actually flying. The hummingbird in question may be dead or asleep in which case the correct answer would be significantly less than the number you provided. Furthermore, the little bird could be flying for half the time and doing other things such as washing his car with the remaining balance in which case the numbers would be further skewed. Be careful for details that seem relevant but actually aren't. If you research how many times a humming bird flaps it's wings a second you discover that many sources state they do not actually flap their wings instead choosing to beat or rotate their wings 12-80 times a second. Now I am willing to chalk flapping, rotating and beating their wings as the same thing and dismiss that argument as semantics although they are in actuality quite different. Now having said that, most sources state that they do something with their wings up to 80 cycles a second. Notice I said wings not wing. Now if said bird flaps (for the sake of argument) his wings (plural) at up too 80 a second then the same bird flaps (again, for argument purposes) his left wing the same number. The corollary to that is he flaps his right wing the same number as the referenced number as well. The mentioning of the left wing in the original question is an added detail not needed for the correct answer. Now please note, the hummingbird discuss was referred to as a male. That was done in no way biased to the male of the species. I could have easily chosen the fairer sex to illustrate my nonsense.

rharshberger said:

Was that a laden or unladen hummingbird?

Click to expand...

And was it a North American or European humming bird?

Adrian

grouch said:

Oh young BB, college may be trying times for you. You are assuming said humming bird is actually flying. The hummingbird in question may be dead or asleep in which case the correct answer would be significantly less than the number you provided. Furthermore, the little bird could be flying for half the time and doing other things such as washing his car with the remaining balance in which case the numbers would be further skewed. Be careful for details that seem relevant but actually aren't. If you research how many times a humming bird flaps it's wings a second you discover that many sources state they do not actually flap their wings instead choosing to beat or rotate their wings 12-80 times a second. Now I am willing to chalk flapping, rotating and beating their wings as the same thing and dismiss that argument as semantics although they are in actuality quite different. Now having said that, most sources state that they do something with their wings up to 80 cycles a second. Notice I said wings not wing. Now if said bird flaps (for the sake of argument) his wings (plural) at up too 80 a second then the same bird flaps (again, for argument purposes) his left wing the same number. The corollary to that is he flaps his right wing the same number as the referenced number as well. The mentioning of the left wing in the original question is an added detail not needed for the correct answer. Now please note, the hummingbird discuss was referred to as a male. That was done in no way biased to the male of the species. I could have easily chosen the fairer sex to illustrate my nonsense.

Click to expand...

LOL! This is why I love TRF!! Good show, Grouch!
(p.s.- I think a hummingbird would drive a Lotus....)

fyrwrxz said:

(p.s.- I think a hummingbird would drive a Lotus....)

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Well, FWIW, Hummingbird was the development codename for the newly-unveiled Mustang GT350. So, I think some of the larger, more kick-ass species would probably drive that...

Also FWIW, to the point of #4, on my first flight for L1, the parachute detached due to a failed snap swivel. However, the rocket was rugged enough to survive to fall with minimal issue. When the parachute finally landed, I reattached it with a new 600# swivel that Ken Allen sold me onsite, and made a second flight fairly immediately. I think the longest part of the downtime was chasing the chute downwind...

DizWolf said:

You can tape the motor in if you want. (positive retention is NOT required.)

I crank my buttons down. if they wear out, I'll replace them. 8 foot of derlin on alum is not going to cause enough drag for me to give a whoop about.

I look at test flights like this: Why? there's zero reason. You're putting the rocket at risk on a likely underpowered motor, for what? to see if it's stable? you know it's stable. That it will fly? You better know it'll fly. That the recovery works? It's a cord and a parachute. There is no penalty for a failed L1. So, why test fly? Fly on the L1 motor. if you succeed...win! if you succeed on a G, you just put a flight of wear on the rocket, risked damage, and still no cert.

I say put an I600 in it and punch it.

Click to expand...

And from the other perspective....

I had my heart set on getting my L1 on the day when my family could be there. My objectives were: don't go too high, don't lose it, don't complicate things. I built an Aerotech Sumo and launched it on Gs several times before I put a baby H in it. By the time I had my cert flight, it was old hat. It just went higher; everything else was the same. Guaranteed success.

As far as the G flights goes, I did What Bat did. There are all sorts of flavors of L1 rockets. Some feel a true L1 rocket is one that only flies on H's and I's. I like the fence riders myself. I like rockets that fly well on F's and G's but can also take H's or even I's if you want. I have a LOC Onyx that has flown just as many times on H's as it has on G's. Now I'll be the first to tell you an Onyx is not at all a L1 rocket but as long as you understand it will go much higher than something like a LOC IV and are prepared to walk for the recovery providing you saw where it went then go for it.

In the end I think the best idea is to determine what you will fly most. If you only see yourself flying H's, I's J's and higher then build something bigger and sturdier and forget about flying it on G's. If you can see yourself flying more G's than H's then build something smaller and lighter. What ever you do, just don't lose sleep over it because you will eventually build another rocket anyway so no big deal.

From experienced level 2: I like the first 2 answers. However, my rail buttons always spin freely, it's in mad cow instructions. ABSOLUTELY use nomex sleeves on all exposed shock chords not in burrito . Don't use tape retention. If u lose your metal reusable motor tube, you will cry. It just makes sense. Be sure to use the 5 to 1 thrust weight ratio for motor size selection. Ask the locals for advice on delay. Use a smaller Hp motor the first time, try to stay at 2500 to 2000 feet so you can see the rocket at all times. NEVER NEVER TAKE YOUR EYES OFF THE ROCKET TO HIGH FIVE YOUR BUDDY, OR YOU WONT FIND IT!!,!!

grouch said:

... count a few questions from the RSO about CG/Cp and your blood type, mothers maiden name and the number of flaps a humming bird makes with it's left wing in a minutes time.

Click to expand...

As a follow up to CG/Cp mention - my recommendation to the OP is to put a mark (permanent or temporary) at the rocket's Cp. This will allow the RSO to quickly determine stability. You can determine Cp a number of ways. If it is a kit, you may be able to find it here:

https://www.rocketreviews.com/what-is-cp.html

Or you can use the free Openrocket program and "build" your rocket in the simulation program.

NEVER NEVER TAKE YOUR EYES OFF THE ROCKET TO HIGH FIVE YOUR BUDDY, OR YOU WONT FIND IT!!,!!

Click to expand...

It also helps to find a 8-10 year old (good balance of eyesight and responsibility) and ask them to help you keep eyes on the rocket. They should point at it at all times from liftoff to touchdown. This makes it much, much easier to find it if you lose it. If it's out of direct sight, also getting a bearing (just left of the white house) is helpful.

I flew on a medium sized G before flying on the baby H to make sure everything worked properly and that the recovery harness holds on both ends. That saved an H motor (at the cost of a G) on both my and my daughter's L1 flights.

thanks everyone.

additionally, how tight should a nose cone be for HPR? or is it the same "you can hold it by the nose cone, but barely"?

For single deploy, you should be able to lift the rocket by the cone and not have it slide apart.

For dual deploy, you may need shear pins or tape to help prevent ejecting the NC at apogee.

I got my level one this year. I choose a big 4” rocket that wouldn’t go too high to improve my chances for recovery.

It took two attempts to get my cert. Both were done on the same weekend. During the first attempt the body was damaged by impacting with the nosecone after ejection. I made a field repair by cutting off ~3” of the body tube, installed another motor with a shorter delay, and sent it up again.

The buttons were set to spin per the instructions.

No swallows, hummingbirds, or coconuts were harmed in the process.

Using a longer harness could have saved your airframe.

blackbrandt said:

Due to the fact a hummingbird flaps both of its wings at the same time, and a hummingbird can flap up to 70 times per second, that would be approximately 4200 times.

Click to expand...

What is the airspeed of an unladen swallow in flight?

runty said:

hey! thinking of getting my L1 in the next while... anyways had some questions

1. how do you use your chute protectors? do you use them like wadding, where you crumple it? or do you "burrito" your parachute (or "taco" it, where the nosecone-facing half is open)? do you put a couple pieces of wadding in there along with the chute protector (to protect the chute protector,lol?)

2. how tightly should you be tightening your rail buttons? secure as hell, free flying or somewhere in the middle?

3. is a collection of nuts/screws/washers correctly assembled acceptable for L1 cert? or do you have to use a retail-style retainer for your cert?

4. if something resulted in disqualification to your L1, but your rocket is still fine to re-fly, do clubs let you re-try your L1 on the same day? i guess this would be a pretty rare scenario, but still good to know.

5. is it good to "test" your rocket on a G motor before flying? or is it better to have your L1 cert be your maiden flight? in this scenario, my "test" would be on the same day as my cert. I wouldn't be able to bring it back home and make any major changes.

thanks!

Click to expand...

The odds of reaching uniform agreement to all of these questions are about the same as those of a certain very warm place suddenly getting very cold, but I will give you my opinions.

1. Wrap your chute and shock cord in the Nomex chute protector and make sure that the "top end" ("the top of the taco") is facing away from the charge. Something else to consider here is to wrap a rubber band around your shock cord to prevent it from tangling with your parachute.

2. Depends on the rail buttons. Some, by the nature of their application, are tight and there is no control. I personally like the Delrin rail buttons sold by Mad Cow because they are small and very well secured into the rocket. I leave some play in them so they roll. The less friction with the rail, the higher and faster your rocket goes. Keep in mind that rails get pretty scorched and pocked as more rockets get launched off them, and that increases the friction. If you are using aerodynamic rail buttons, the manufacturers general recommend tht they be kept fair loose so they don't get hung up in he rails.

3. Motor retention is your own call. Just remember that if the motor comes out...you fail. That's why most people opt for commercial retention. For my L1, I personally used my own, imbedding and gluing in two threaded rods into the aft CR and then using nuts and washers to hold the motor into place. When it landed, one of the nuts and washers had come loose, but the other held, and I still passed.

4. Our club probably would. Hypothetically, you could go to a vendor, buy a new kit, assemble it at the field and fly it that afternoon. If your rocket was repairable, but not "within five minutes," you should also be fine.

5. You always run the same risk of motor failure with a test flight as you do with a cert flight, so it's up to you. If you decide to do this, use a G that has as much initial thrust as possible. Look at the thrust curves of the motors. That way you see if it can handle the force of the H motor you intend to put into it. Most construction failures happen at launch, so if you had a weak glue joint, it would come apart soon after he launch. The burn is generally shorter (unless you are using an H410), so the overall damage would be less than if you used a high power motor. But if you are using "baby H's" (say about 5-10% of an H) you may as well skip a test flight. For example, a CTI G54 has a total of about 159 NS, and a H54 has about 161. Barely any real difference. May as well certify on the first try.

different opinions help, thank you!

Well, what next? We are all happy to help but want to see the results too!

My answers are pretty similar to everyone else, but I'll put in my 2 cents as well.

1. how do you use your chute protectors? do you use them like wadding, where you crumple it? or do you "burrito" your parachute (or "taco" it, where the nosecone-facing half is open)? do you put a couple pieces of wadding in there along with the chute protector (to protect the chute protector,lol?)

I tend to go "burrito" style. This makes sure that you are protecting the parachute from being burned by ejection charges. If you want to get really fancy, use a deployment bag. (not really necessary unless you are using a fancy parachute). I usually add dog barf (wadding) as well to further protect the chute, nomex, and shock cord. Dog barf is cheap and doesn't take anything away from your over all mass.

2. how tightly should you be tightening your rail buttons? secure as hell, free flying or somewhere in the middle?

I make my rail buttons loose. While DizWolf is correct, you aren't going to see a lot of wear over 8ft on the rail buttons, this wear translates directly into loss of altitude. Free spinning reduces your friction on the rail. In all the flights that I have done, the only time there has ever been a problem with loose buttons was after high cycles of moving the buttons. Unscrewing and screwing the buttons into the same holes. But this was a problem with the airframe, not the buttons. Its really about personal preference and your air frame/tapped hole. If your frame is soft... Torque 'em down since they might move otherwise, if it hard (FG or CF) let the buttons spin, they won't come unscrewed.

3. is a collection of nuts/screws/washers correctly assembled acceptable for L1 cert? or do you have to use a retail-style retainer for your cert?

Some kits even use nuts/screws/washers for the retainer. While a prefer the aerotec retainer, its not required... It just looks nice and is super easy to use. Either way... you want to make sure you don't lose your casing... speaking from experience, there is no feeling like having a successful flight, only to find out you lost your motor casing...

4. if something resulted in disqualification to your L1, but your rocket is still fine to re-fly, do clubs let you re-try your L1 on the same day? i guess this would be a pretty rare scenario, but still good to know.

This is up to the club, but in most cases they want you to succeed. My experience is that they will probably try to help you fix it so you can get your cert. My L1 crashed the first flight (super unstable due to an over-site in the sim by myself and someone that was helping me). It landed safely, but wasn't a cert worthy flight. Added weight to the nose cone and flew again with no problems.

5. is it good to "test" your rocket on a G motor before flying? or is it better to have your L1 cert be your maiden flight? in this scenario, my "test" would be on the same day as my cert. I wouldn't be able to bring it back home and make any major changes.

I'm of the philosophy that if it works it works, if it doesn't, it doesn't. If it is a super expensive rocket... I might test it with a lower power (cheaper motor) as long as it is a safe flight! Testing with a lower power will only get you so far if the flight isn't close to what it would be with a L1 motor. I haven't tested any of my rockets with a lower power motor, but its really up to you. I don't see the benefit of it, so I don't do it.

1. how do you use your chute protectors? do you use them like wadding, where you crumple it? or do you "burrito" your parachute (or "taco" it, where the nosecone-facing half is open)? do you put a couple pieces of wadding in there along with the chute protector (to protect the chute protector,lol?)

Wrap it like a burrito and make sure it fits into the airframe but not too tight

2. how tightly should you be tightening your rail buttons? secure as hell, free flying or somewhere in the middle?

Your rail buttons should spin freely

3. is a collection of nuts/screws/washers correctly assembled acceptable for L1 cert? or do you have to use a retail-style retainer for your cert?

Some flyers construct their own home made type retainers using nuts, bolts and washers

4. if something resulted in disqualification to your L1, but your rocket is still fine to re-fly, do clubs let you re-try your L1 on the same day? i guess this would be a pretty rare scenario, but still good to know.

Not sure but I think as long as the rocket is safe to fly again?

5. is it good to "test" your rocket on a G motor before flying? or is it better to have your L1 cert be your maiden flight? in this scenario, my "test" would be on the same day as my cert. I wouldn't be able to bring it back home and make any major changes.

I never did. My L1 flight was the maiden flight for my SUMO and on top of that I drag race my friend for his maiden L1 flight

I'm going to Ditto most everyone else.
- I didn't know buttons should spin freely.
- I really like AEROPACK style retainers for ease - and if you store your rockets standing up!

Rail buttons optimally spin freely to reduce friction against the rail. But it is not a do or die. Some of mine spin and some don't, and both work.