What did you do rocket wise today?
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Yesterday's lost and found rocket flight. Memory card in the Astrocam was fine. 8s delay on the F52C was a bit short, but glad I didn't almost lose a casing. Not much to this bird, just a PSII 2" booster, two sections of body tube, coupler with baffle and the nosecone.
Also a poor snap of my 3" Gobblin (turkey themed), going up on an AT G53.
Also a poor snap of my 3" Gobblin (turkey themed), going up on an AT G53.
Charles_McG
Ciderwright
I'm working up the post-flight analysis of my flight from above/yesterday.
Blue is from the Proton, red is from OpenRocket. I find it interesting that the Proton reads a higher accelerometer velocity then the sim during the first boost, even though the read acceleration was lower. I'm going to chalk that up to a calibration offset.
The H175 seemed to burn out a bit early (0.15 sec) I updated the coast time in the sim so the second burn was aligned.
From the overflight profile, it looks like the sustainer is a little draggier IRL than in the SIM.
And the baro velocity shows the dual deploy nicely.
Blue is from the Proton, red is from OpenRocket. I find it interesting that the Proton reads a higher accelerometer velocity then the sim during the first boost, even though the read acceleration was lower. I'm going to chalk that up to a calibration offset.
The H175 seemed to burn out a bit early (0.15 sec) I updated the coast time in the sim so the second burn was aligned.
From the overflight profile, it looks like the sustainer is a little draggier IRL than in the SIM.
And the baro velocity shows the dual deploy nicely.
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Launched rockets! Will wonders never cease!
https://www.rocketryforum.com/threads/personal-launch-report-mdars-2022-07-23.173920/
https://www.rocketryforum.com/threads/personal-launch-report-mdars-2022-07-23.173920/
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Yipeeeeee! Congrats and gj not giving up...
Last night, did initial sanding of a KN Aeronautics Sidewinder 3D printed nose cone. Attached rail guides to my PS II Nike Smoke. Put fillets in my Klima Andromeda.
Ran through my supply of primer:
Aforementioned Nike Smoke in the foreground, Aerotech Strong ARM, airframe pieces of my MAC Performance Black Fly. Not visible: younger son's Nano Magg, both airframe and nose cone, and older son's Micro Magg nose cone. Now I need to find that primer in bulk.
Ran through my supply of primer:
Aforementioned Nike Smoke in the foreground, Aerotech Strong ARM, airframe pieces of my MAC Performance Black Fly. Not visible: younger son's Nano Magg, both airframe and nose cone, and older son's Micro Magg nose cone. Now I need to find that primer in bulk.
Tell me about it. Had to buy a new ca
Tell me about it. Had to buy a new can for my AT Sumo. Two nearly empty cans didn't cut it.
Tell me about it. Had to buy a new can for my AT Sumo. Two nearly empty cans didn't cut it.
The SEM brand hi-build primer is $15/can
"What did you do rocket wise today?" Something! It's been a long time, and I finally got off my ass and did something.
The rocket relatedness is indirect, but rocketry is the ultimate goal.
A few weeks I salvaged the piezo transducer disc from a dead radio that had been its tweeter, with the thought of making it into a locating sounder. It's just a bare disc that had the radio case for a resonator, so I'm going to need a new resonator of some kind. So I made an oscillator out of a 741 I had on hand so I could start experimenting with the acoustics. And I glued the piezo disc into one end of a 29 mm coupler so I can insert it at various depths into a 29 mm BT, closed off or sealed at the back end.
If the acoustics work out, there's a dual VCO chip I plan to buy and implement a siren.
So far the results are disappointing. I may get get some improvement with the right tube length, but I doubt I'll get enough to be worthwhile. Oh well. I did something.
The rocket relatedness is indirect, but rocketry is the ultimate goal.
A few weeks I salvaged the piezo transducer disc from a dead radio that had been its tweeter, with the thought of making it into a locating sounder. It's just a bare disc that had the radio case for a resonator, so I'm going to need a new resonator of some kind. So I made an oscillator out of a 741 I had on hand so I could start experimenting with the acoustics. And I glued the piezo disc into one end of a 29 mm coupler so I can insert it at various depths into a 29 mm BT, closed off or sealed at the back end.
If the acoustics work out, there's a dual VCO chip I plan to buy and implement a siren.
So far the results are disappointing. I may get get some improvement with the right tube length, but I doubt I'll get enough to be worthwhile. Oh well. I did something.
Scanned the relevant pages of IPC-620 Standard (Requirements and Acceptance of Cable and Wire Harness Assemblies) and sent that through to the university team I mentor. It was one of the hurdles that we found before going to Spaceport America Cup this year. Now they will know what "target condition" for crimps look like, what is acceptable, and quality and consistency will improve.
read part of the sugar motor site contents, watched videos on it making motors for 50 cents.
I paid a little over $10 for Rusto sand & fillThe SEM brand hi-build primer is $15/can
Redid the epoxy on my nose-cone extension/repair since the last whiff of 5-minute I'd used before had been light on the hardener. Dipped <ahem> starters for some preliminary testing for the goal of clustering composites. Cut tubes for some shear pin testing. Watched Jim Jarvis' video of the Python flight and read Joe Barnard's report of propulsive landing, two milestones that have been a long time coming (7 years in Joe Barnard's case).
I got another one ready for paint...
We have to meet Sept 5th at the Freedom Launch
Assembled 3 eggtimer Quarks. Well, almost. One was missing a voltage regulator.
It really does go faster when you can assembly line them and do multiples at once.
It really does go faster when you can assembly line them and do multiples at once.
What are the dates of the Freedom Launch?
Sept 3,4, 5
berlinetta
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I didn't do much this weekend as is was way too hot. Since I'm going to be making the trek to MDRA in April, I'm slowly getting ready now. I made a list of what I need to get. Friday, I managed to knock off 6 items of a list of 12.
Saturday morning I went and bought a quick link for my LOC IV and that's now completed.
This week is going to be fillet week. Going to be doing the fillets on the Parkflyer Magnum and starting the external fillets on the 5.5" Magnum.
Saturday morning I went and bought a quick link for my LOC IV and that's now completed.
This week is going to be fillet week. Going to be doing the fillets on the Parkflyer Magnum and starting the external fillets on the 5.5" Magnum.
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berlinetta
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Got my TRA level 2 cert
Congratulations!
@lakeroadster's Thunk gave me an inspiration. I'm making a similar rocket. It's a 29mm motor tube. 4 fins top and bottom. 24" long. I have a 3" x 48" mortar tube that I fly a rocket that looks like a 60mm mortar bomb out of. I have sized the fins to fit inside the tube. I have the fins on and the nose cone has a load of BB's and epoxy. If needed I'll add more weight below the nose cone. Now I need to pick a motor. G80-13 maybe. Probably not a good choice for a first flight. I'll pick a motor that will keep the rocket in sight. I think that by the time the rocket clears the tube it will be spinning like a top. That last line made me think, when was the last time I played with a top. Easy answer. A long time ago. Late 60's I think. The mind is amazing. I can picture the top in my mind. It was wood with a metal tip. Red I think. But I can't remember what I did last week. When was the last time you all played with a top? I know. I'm rambling.
Congratulations. That's awesome. Tu for sharing .
Congratulations.Got my TRA level 2 cert
A "proper" top such as you're describing? I'm not sure ever. Battling Tops? I don't remember when, but more recently than you'd think at my age. A dreidel? Ditto. Making various objects stay upright by spinning? Every now and then. Thumb tacks work really well.
I likely threw one and landed a good spin sometime around 6 or 7 years ago. Serious play (is that a thing?) was probably 1970-ish, we would sharpen the tips and try and split each other's top upon initial throw, if you missed you got a second chance to pick up your top, and knock over the competition's top before yours stopped spinning- success, you throw again, miss and yours becomes the target. For that reason just how sharp you made your top's metal tip was a trade off. I suppose splitting each other's tops was 'serious' after all...
lakeroadster
When in doubt... build hell-for-stout!
Does a gyroscope count? I clearly remember playing with one of those, circa 1967 ish. I think every kid in America got one of those for Christmas, they were all the rage!
I don't know piezos other than being aware of their capacitive nature.
For a high-Q response using a dynamic driver, that would mean an enclosure that's way smaller than normal.
A horn would be better, you could make a small throat in front of the element and an expansion to the ID of the tube, proportions of which would be influenced by the driven frequency.
Perhaps easier to make it in the proportions allowed but the tube, and adjust frequency for best output. I'd substitute a trim pot for the R to diddle around. Square wave?
Yes, square wave, for now. That's what you get from the CHAD oscillator that I made in a hurry. (You can get a triangle wave from a different node in the circuit, but the amplitude is a bunch lower.)
In the end, I wouldn't want the Q to be really very high, since I want to change the present oscillator to a siren, and a very high Q doesn't do nice things to a fluctuating frequency drive. The disc itself can't have a very high Q, since it was being used as a tweeter.
Part of my problem may be the disc's size, which is a smidgeon small inside a 29 mm coupler. (I added some tape to the inside of the coupler.) I'm trying to use a tweeter driver down at about one kilohertz. At present I'm driving it at about 1.2 kHz, which means about 11 inch wavelength in air, and the driver's diameter is only about 1". Is that really important? I don't know much in the acoustics world - only a little more than nothing - but it does seem that this is a thing that might matter.
There are other parts of the electronics that could surely use improvement, most notably that I'm driving a square wave through a DC blocking cap, and said cap was chosen at random out of the drawer. But there's little or no point in thinking too hard about that part now, since this isn't the oscillator I'll use in the final design. (Still, I could try fiddling with that blocking cap a little.)
In the end, I wouldn't want the Q to be really very high, since I want to change the present oscillator to a siren, and a very high Q doesn't do nice things to a fluctuating frequency drive. The disc itself can't have a very high Q, since it was being used as a tweeter.
Part of my problem may be the disc's size, which is a smidgeon small inside a 29 mm coupler. (I added some tape to the inside of the coupler.) I'm trying to use a tweeter driver down at about one kilohertz. At present I'm driving it at about 1.2 kHz, which means about 11 inch wavelength in air, and the driver's diameter is only about 1". Is that really important? I don't know much in the acoustics world - only a little more than nothing - but it does seem that this is a thing that might matter.
There are other parts of the electronics that could surely use improvement, most notably that I'm driving a square wave through a DC blocking cap, and said cap was chosen at random out of the drawer. But there's little or no point in thinking too hard about that part now, since this isn't the oscillator I'll use in the final design. (Still, I could try fiddling with that blocking cap a little.)
Since a piezo tweeter is essentially a a capacitor, an added series cap functions an attenuator. Analogous to a resistor in series with a dynamic tweeter. So that cap value could be critical.
DC blocking shouldn't be necessary, as the element doesn't have a DC path. But some series resistance could be needed if the frequency gets high enough to cause a low-impedance situation for the op amp.
DC blocking shouldn't be necessary, as the element doesn't have a DC path. But some series resistance could be needed if the frequency gets high enough to cause a low-impedance situation for the op amp.
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