You can borrow my 29/240 RMS case.

I will be there all day Friday and Saturday. I am in no hurry
You can use the case any time. I will be doing most of my
launching Friday.

There can be an anouncement made over the loud speaker
to get all of us to You.

Have a great day

Thanks. Hopefully that will be my second launch. What is your last name, and/or what do you and your biggest rocket look like?

Geof

Geof, there are so many in the club who can certify you. I'll be RSO Saturday afternoon, so I can't then. I plan to get their Saturday morning ~10 AM. I'll be available just before and after my RSO duties. I'd be very happy to do it. Go to our Prez, Joe Hinton; he can point out everyone who can do it. Just remember to bring your paperwork--yes, there is a L1 cert form, and give it to Joe after you've certified. He gets the fastest response from NAR.

mike shinn

click the www tab....You can see me and my rockets.

geof, I have a 38-240 you would be welcome to use.

Brian K

Thanks; how can I get in touch with you or find you?

And, who do I contact about buying the right reloads?

And, who do I contact about buying the right reloads?

GLR's Tim Thomas (tim4glr@aol.com). He always has quite a range of reloads, but you should e-mail him ahead of time, just to make sure he has what you need. Just some quick tips... make sure you have vent holes (if you don't, I always have a cordless drill and some bits), a good harness (no elastic--though technically you can, just not strong enough for high power), positive motor retention (some may let you cert with just masking tape, I would prefer that you use some kind of hook or commercial retainer). On a L1 attempt, my rocket shot out the motor casing, and it landed within 60 feet of Nadine Kinney. I NEVER flew without proper retention after that. Make sure you know your CG/CP for stability, that you can hold your rocket by the nosecone or upper section and it doesn't separate under gravity, that you've simmed your rocket to know what delay to use: S? M? or L? Tim has the RDK delays to change to whatever you need. And, a parachute big enough for a safe recovery, but not too big to where it flies away. Did that. 🙄 There's no written test (only for L2), so it's just present your rocket, whoever certs you should ask most of the above questions while looking your rocket over, then just launch. Your rocket must have a successful, safe flight without popping your nosecone off... Did that, too. 🙄 What's traditonal and kinda cool is that after you've done your L1, the response will be "Welcome to high power!" L2: "Welcome to higher power!" L3: "Welcome to highest power!" It's a fantastic journey, Geof.

I don't think I'm going high enough quick enough to need the hole. Around 750ft on H165.

About the nose cone...a question. Yes, I know that rule of thumb. My rocket has a ton of nose weight: the nose weighs as much or more than the rest of the rocket. I'm nervous about the motor having enough ooomph to eject the nose. Thus, I'd rather have the nose looser.

Also, due to the concavity of the body shape, the body actually narrows slightly from the parachute storage area upward to the nose cone seam. Thus, the parachute must slip through a slightly increasingly constricted space to deploy successfully. Therefore, I want that nose cone popped with maximal force to help pull out the chute. Don't want it to barely scrape off.

On the other hand, the shoulder is narrow (0.5in). The fit is fairly smooth and loose, but not perfect.

Any of this alter change your advice on nose snugness?

Also, what is the default time for the "S" delay? I need about 6 sec.

Everything else you suggest is done, in spades. Thanks for the advice...I'll write to Tim tomorrow.

Geof

Make sure the charge from an H180 (about 1.3 g) is enough to pressurize the tube so the nose blows out along with all of the laundry. I had one rocket where the supplied BP was not nearly enough. The nose popped out, but nothing else. Keep the volume of the paylod pay bay to a minimum - only what is needed to hold the chute, harness, nomex and shoulder of the nose. Use a BP calculator to confirm.

The 29/240 fits in the motor tube which I designed for 29/60-120, but sticks up beyond. The nose is mostly full of weight. Aside from a bit of empty space around the motor casing and around the nose weight, this leaves 4 inches of vertical space @ approx 4in diameter, which is absolutely 100% filled with recovery gear.

Using EMRR's calculator, 4x4 => 0.26g for 10psi, 0.51g for 20psi

That's reassuring. As mentioned above, the worry is that the nose cone has greater mass than the rocket. I suppose Newton's 3rd law implies that that doesn't matter.

I suppose Newton's 3rd law implies that that doesn't matter.

Regarding Newton, there is one famous and infamous expresision that we've all heard and used, "Well, in theory, it should have worked." Let me say something about Ken before I go on, he nailed his L1 and L2 with perfect flights, first time on both. And, I'm sure when the time comes, he'll do it with his L3. I, or anyone who certs you--Ken's a good choice, too, BTW--will have to see your rocket in person. Did you ground test in anyway? Because of your unique and really cool design, that is advisable. Though you couldn't do it without a motor casing and separate charge canister. I can bring the stuff you need except for the motor casing to OF, just let me know. Don't trust a heavy nose to keep it on. In fact, and this goes along with Newton, if the nosecone is the heaviest part of your rocket, it will move away from the booster due to momentum and the fin drag of the booster. The pressure change is due not only to altitude, but a sudden change in pressure. And, it's more than you really think. Plus a loose fit causes gas from the ejection charge to escape without doing its job, i.e. a pressure leak. Not good. I've shot nosecones off twice and stuck the chute with a charge, not lack of vent holes--don't be conservative with ejection charges. I can't imagine anyone who would certify a rocket with a nosecone too loose and not able to stand up to being held by the nosecone without separation. There are exceptions but few. All certs are heads up. But be sure you tell all this to whomever is going to certify you, so he can make sure it's pointed away from the crowded areas. Then again, Geof, all your opinions and calculations may be right for this particular rocket. You are ultimately responsible for the rocket's flight and safety. Only takes one successful flight to certifying at any level. However, what's been mentioned by Ken and me will have to be followed at some point for you to grow and get higher power. I also saw your glider(s), and they were fantastic! You have the skill you need, just listen to what others have to say and look at their rockets. Ken and I are only two people, and there are a lot more with great advice.

In fact, and this goes along with Newton, if the nosecone is the heaviest part of your rocket, it will move away from the booster due to momentum and the fin drag of the booster.

Plus a loose fit causes gas from the ejection charge to escape without doing its job, i.e. a pressure leak.

These are good points. Okay, I'll tape the shoulder a bit for a more snug fit.

--don't be conservative with ejection charges.

The ejection charge is 5x the level recommended by the calculator (see a previous post).

The ejection charge is 5x the level recommended by the calculator (see a previous post).

I'm sure you're right. If you have such a small area to pressurize, 1/2 gram or less. Your call. Since you're going to fly the rocket with a G or two, find out what the ejection charge is in the G's you'll be using. If they work, that's the charge you need.