Search results

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
  1. kramer714

    Black powder?

    Sundays are quieter than Saturdays up at ROCstock, depending on the crowd and the weather they launch to 12:00 or later. Come up after your class on Saturday, Night Rockets is pretty cool, plus there will be lots of folks camping out,
  2. kramer714

    Black powder?

    Going to ROCstock? I can 'lend' you some. Mike K
  3. kramer714

    Simple 54mm dual deploy av bay - 3d printed sled

    Yup, aerospace engineer. Working on hydrogen fueled aircraft now, previously owned a composite company. Been involved in aerospace for over 30 years. I try and bring some 'day job stuff' to the forum. Lots of the problems folks on here have, have already been solved commercially, and can be...
  4. kramer714

    What Epoxy Do You Use?

    not to be that guy.... but... Depends, on what I am doing. For bonding fins (highly loaded), I use DP-420 or DP-460 gray I use this for 'laminating' boat tape or other cloth in joints or fillets. For bonding fins lightly loaded or using fin pockets, I use 30 minute epoxy (sometimes 5 minute)...
  5. kramer714

    homemade casings for rockets

    Yeah, a few things to unpack here, Motor Case - Under Pressure BETTER body tube, so the motor case stress go DOWN axially if it is also the body tube. Easy to think about, the pressure creates axial stress in tension, during launch on a 'body tube less design' the tube is in compression...
  6. kramer714

    homemade casings for rockets

    Wind angle for the case is VERY important, it affects the overall pressure rating, but, as important it affects the mode of failure and the case deformation under pressure. Also important to the wind angle is the method used to hold the ends on. At the day job (ok actually previous day job...
  7. kramer714

    3D Printing What did you 3D Print Today?

    STL files for the 54mm apogee nose to finish, drill / tap for 1/4-20 eye bolt drill tap for 10-24 top mount drill tap (4 places) 4-40 altimeter mount drill tap (1 place) 4-40 for wire holder drill tap (2 places) 4-40 for battery retainer drill / tap (3) #6-32 holes in the base (nosecone attachment)
  8. kramer714

    3D Printing What did you 3D Print Today?

    cross section cut of the worm, you do want nice fillets where the worm exits the part to avoid a sharp corner.
  9. kramer714

    3D Printing What did you 3D Print Today?

    sure, These are 'pull through plug' used to mask holes for plating or painting. they work well for sealing wires in holes too. You pull the skinny side into the hole and when you pull it through the 'worm' gets smaller in diameter, let it go and it expands filling the hole. One way is to...
  10. kramer714

    3D Printing What did you 3D Print Today?

    Another nosecone / altimeter combo. 54mm cone, inside is a 1s 220mAh battery, eggfinder apogee, ComSpec Tracker. Rubber Worm seal for the wire.
  11. kramer714

    Converting motor N-S to Joules

    I work in 'electric aviation', and was involved in runaway testing. I looked at using a grain as a substitute, I gave up on the idea because, We got pretty good at getting cells to blow on demand Depending on what we were going for, the battery case rupture was part of the failure mode that we...
  12. kramer714

    Eggtimer Apogee issue

    Egg finder apogee (well used one) turned on without a charge connected
  13. kramer714

    Hybrids 2024

    LoRa
  14. kramer714

    Hybrids 2024

    wireless
  15. kramer714

    Hybrids 2024

    i use teflon tape, and always use a solenoid saver!
  16. kramer714

    Shock cord protection - RTV silicone?

    looks like..
  17. kramer714

    Shock cord protection - RTV silicone?

    The issue with shock cords is usually just where it attaches to the rocket and where it hits the edge of the tube. Shock cord protectors take up a lot of room in the body tube. One simple solution is to use thin galvanized or stainless cable. On some small rockets i use Amazon 1/16 steel...
  18. kramer714

    Kevlar Shock Cord Damage

    dumb question, did you have a vent hole in your body tube? Just asking....
  19. kramer714

    Good HTPB hardeners

    Haven't really considered that, for the hybrids I do they are all fill on the pad and single use o-rings, i do have experience with dynamic seals, they do behave differently. Other question is grease, I typically use Krytox, but Conrail instructions call out mobile 1 synthetic grease.
Back
Top