...
- When in flight are those fin lift & drag loads from a couple slides ago from? Confusing sentence but did you assume 5/15/whatever degree angle of attack at Max-Q or something
- Have calculations on the profile drag been done to ensure the drag separation?
-Are the 5 plies just to make the fin continous with the phenolic?
-What will the upward facing aeroshells look like?
-For simulations, are mach numbers calculated basedon decreasing air pressure or sea level?
-What finish was used in the sims?
-Do simulations take into account grain geometry?
Comments:
- One piece of advice is idk which method you used in rasaero. There is the barrowman and the rogers modified barrowman method. This second one gives the best results so you can knock your safety factor down for temperature if u need.
- Can sanding carbon fiber edges to get a point instead of using phenolic (esp for trailing edges)
- G410? or something for epoxy
- Make sure the weaving of the carbon fiber alternates between 0 and 45 degrees to maximize tensile strength
- RAS Aero has a perturbance protuberance feature, but he doesn't know if it works
...
Questions:
- How did we know ASIT wasn't going to work? Is there data behind this or story or calcs?
- Don't we only need one pin to stop rotation? Why 4?
- Did you do calcs for the eye-bolt? Is there a secondary retention mechanism?
- Does the anti-rotation rod interfere with anything?
- Have there been axial calcs to confirm the bottom bolts on slide 19 won't just rip out? (Concerned about them not having a lot clearance)
- Will the capsule holding the black powder be sealed so proper ignition occurs?
- Are the parachutes reefed?
- What are the initial velocity inputs for the shock calcs?
- What are the plans to improve the reliability of the tender descenders?
- Are there any ground testing planned for any of these systems?
- Is there a mass margin generated from our motor performance? When we weigh all of the parts will we know whether we beak break that margin?
- Why do you have a factor of safety for the bulkhead? It won't be bearing load
- Did the lead engineer design the board layout or was it avoinics?
- Any concern with RF signals with all of the metal hardware?
- Can you explain how decreasing the length fo the rocket overall leads to a reduction in roll instability? (gil answered and said stability >3 bad)
-Where did the 460lb load on piston mount come from?
Comments:
- May be a good idea to tape the dowel pins slightly. There could be a situation where the friction from wanting to rotate prevents separation
- when showing FEA, show supports and loads set up
- FoS should be set by us. Then margin yield and margin ult: MSy = yield strength/(FoS_yield*analyzed stress) - 1. Above 0 is good, below 0 is bad. FoS will be different for yield and ultimate
- include color bar in FEA
- Scale for FEA. Need boundary conditions. Need constraints
- reiterating that FoS is set by us and the margin is the result
- "Jorian have you gotten accelerometer data from other flights to ground vibe environments"
- On the roll-coupled instability & length convo - as I remember it static stability margin & longitudinal mass moment of inertia influence this a lot (especially at resonance roll rate). This article has some good info, I think there are more that I'm looking for and will send after review. http://www.ninfinger.org/rockets/ModelRocketry/Model_Rocketry_v01n05_03-69.pdf
https://www.ninfinger.org/rockets/ModelRocketry/IndexToVolume1.html
...