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  1. richP

    Pressure relief holes

    Should be fine. Most people put vent holes towards the top of each section. Upon boost, the laundry shifts down to the bottom of it's section, keeping the vent hole clear.
  2. richP

    Inadvertent main deploy at apogee

    Well. I finally had the chance to really take apart and inspect all of the pieces. I beleive that this explains what happened: The swivel on the left is on standard Fruity Chutes drogue, the right is the one on this particular rocket. So apparently, the brakes were hit pretty hard, causing the...
  3. richP

    Inadvertent main deploy at apogee

    Don't have any good video, but this is a still shot of the beginning of the flight, in which you can clearly see off-vertical turn.
  4. richP

    Inadvertent main deploy at apogee

    That's the funny part. It is 2.2 calibers overstable; so not anything crazy. Previous flight with a similar motor and stability was dead straight. Wind was gusty, but not to the point of really out-of-line. I keep coming back to the missing chunk from the nozzle as contributing to the...
  5. richP

    Inadvertent main deploy at apogee

    This is the 3rd flight with this setup. The previous flights deployed perfectly. I could probably go a little longer on the shock cord, but if the cause of this was too much velocity, then I don't know if adding a couple of feet would have prevented it.
  6. richP

    Inadvertent main deploy at apogee

    Harness is 32' long kevlar. I thought about ejection charge pressure bleeding into the AV bay, but the altimeter data shows the main charges deploying at the correct altitude. Right now, I tend to think that the high velocity at apogee deplyment (due to way less-than-vertical boost) caused the...
  7. richP

    Inadvertent main deploy at apogee

    Primary Backup I do notice the velocity "spike" during drogue deployment.
  8. richP

    Inadvertent main deploy at apogee

    Initially, I was sure that I must've misconfigured the altimeters. Once confirmed that they were OK, I'm now starting to think that the high airspeed was a contributing factor, which would be a one-off. The altimeters aren't telling me the real airspeed due to the not-so-vertical flight path...
  9. richP

    Inadvertent main deploy at apogee

    Had a strange occurrence yesterday and figured I'd get some groupthink goin on the matter. Launched a rocket using an M1315. Total weight was 37lbs. and simulation altitude would be 11,700'. Wind was gusty up to around 12 mph. Rocket ignited fine, but began to weathercock just after liftoff...
  10. richP

    Need some advice for pushing my fiberglass Painkiller 3 a bit harder

    OK. I didn't see a tracker in your OR file and figured it would move the CG forward a bit if you installed one; in addition to helping recover the rocket. Otherwise, I think you'll have little to worry about. You could probably push it even faster/higher, if desired. Just don't forget the...
  11. richP

    Drogue chute sizing

    Desired descent rate. That figure would take into account things like field size, anticipated altitude, rocket profile and weight. Generally, the consensus is that around 60fps to 100fps is about right. If your rocket has a profile (big fins, lightweight construction,etc.) that is somewhat...
  12. richP

    First Fiberglass Kit - Mach 1 Nike XII

    Might not be a bad idea to get a switchband in there too. Will make it much easier when drilling the altimeter vent holes as well as electronics activation components. JB Weld is fine, for both motor retainer and fins. Rocketpoxy is also just fine on the fins. You can use any altimeter you...
  13. richP

    Drogue Chute

    You'd have to get the total weight w/motor hardware and then plug it into Openrocket to find an estimated descent rate. You can guesstmate the Cd. to get a good idea. I usually aim for around 75ft/s under drogue. Keep in mind that many folks go drogueless too, so a chute too small is probably...
  14. richP

    Black Powder Residue Cleaning

    From my muzzle loading rifle experience, Triple 7 was not really much easier to clean. It had a bad habit of developing a crusty residue that took some effort to remove. Regular old blackpowder cleaned very well with hot water and dish soap. Swiss powder tended to burn a little cleaner. The...
  15. richP

    Minimum length for a Dual Deployment payload bay tube?

    That's how a lot of folks do it, and nothing wrong with it, although it is not a traditional dual-deploy. There are quite a few creative ways to save weight on a rocket without shortening it. Use lighter hardware components, aluminum instead of steel, kevlar instead of nylon, high...
  16. richP

    BP charges

    Are you testing with the chutes and shockcord in place? Nosecone sealed for main? Motor inserted for drogue? I agree that you shouldn't need to go much over 90 lbs force to get thru (3) 2-56 pins. Using my calculator, 2.1 grams should be enough for (11) 2-56 shear pins.
  17. richP

    Aerotech's Million Dollar - Million Foot Challenge

    Not unless he was hoping to get to Mach 14 and just coast the rest of the way.
  18. richP

    How to best "practice" with epoxy...

    Get one that sands easily, lol... You could buy a cheap kit and work on assembling it, and you'll have another rocket as a result. Which epoxy were you planning on using? There are many kinds, and some have much steeper learning curves than others. Stay away from the 5 minute stuff, sets too...
  19. richP

    Pressure relief vent hole

    Just keep each of these holes somewhat forward so that the laundry has less chance of plugging it. 1/8" should be fine.