200 grams is a lot of nose weight (as if I have to tell you that; that's almost enough to give it an actual warhead)! Swing testing this guy might be a challenge, but it may be worth the effort.
On the other hand, if I use 6 fins that represent roughly the cross section of the ring tail element.
200 grams is a lot of nose weight (as if I have to tell you that; that's almost enough to give it an actual warhead)! Swing testing this guy might be a challenge, but it may be worth the effort.
The challenge I anticipate is from the likelihood that the CG will by on a tapered area, not from the weight. It's fastening the string. No doubt doable.
Does the frontal area of the (6) fins approximately equal that of the ring?
Does the weight of the (6) fins approximately equal that of the ring?
My F-79 weighs 500 grams...
200 grams is a lot of nose weight (as if I have to tell you that; that's almost enough to give it an actual warhead)! Swing testing this guy might be a challenge, but it may be worth the effort.
I understood, but no, my point was it'd be better to take the trouble to swing test than to put on 200 grams of nose weight "just in case".Sorry, you mentioned the weight, so I though that was your point?
I understood, but no, my point was it'd be better to take the trouble to swing test than to put on 200 grams of nose weight "just in case".
I understood, but no, my point was it'd be better to take the trouble to swing test than to put on 200 grams of nose weight "just in case".
Does the frontal area of the (6) fins approximately equal that of the ring?
Does the weight of the (6) fins approximately equal that of the ring?
I also use (6) rings to simulate the ring fin.... Per Issue 27 of the Apogee Peak of Flight newsletter.
My F-79 weighs 500 grams...
Geepers me thinks you worry too much. I would worry more about the roc‘s parachute working, or a straight normal flight, or the motor ignition and not a CATO….more than if it’s too strong to take a hard landing.Ooh, I detect a dangerous trend in the offing. I'm certainly not accusing you of anything, Just looking at the future. If 3D printing makes parts tougher, will people gradually start thinking that harder landings are acceptable, little by little? Leading to landings that are nothing the rocket can't take, but unsafe for other reasons? Is this something to watch out for?
If the design is simple enough to fall well within the ability of a well proven simulator (i.e. RS or OR) then I for one do not think it's always necessary. And it doesn't have to be just a 3/4FNC; there's quite a bit of room in between those and, well, this. And I think it'd be possible to approximate this in OR with sufficient conservativeness to skip the swing test, I think. But that's what leads to a half pound of nose weight.
Taking 10 minutes to do a swing test.. vs.. possibly crashing the rocket... to me the 10 minutes is time well spent. But opinions vary.
I have yet to verify, with a swing test or an actual launch, Bruce S. Levison's advice on the use of 6 flat fins to simulate a ring fin in Open Rocket. Since the rocket being discussed here has a ring fin, not doing a swing test here would be haphazard, IMO.
I'm also wondering, especially in the case of ring fins, if the slow ft/s experienced with a swing test gives an accurate reflection of high speed stability?
Why pick one?I would worry more about the roc‘s parachute working, or a straight normal flight, or the motor ignition and not a CATO….more than if it’s too strong to take a hard landing.
I don't think there is much of a problem with speed (IMHO, based on experience), but the swing test should try to emulate a straight flight to some degree. That can be problematic for larger rockets as larger rockets need longer string to approximate a straight flight. The good news is that the test is conservative in that it is more likely to fail if using too short a string. If you pass the swing test it should just work.I'm also wondering, especially in the case of ring fins, if the slow ft/s experienced with a swing test gives an accurate reflection of high speed stability?
Looking good.
Keeping it gives you options later.I decided not to use a launch rod for this one and instead use the Makerbeam rail. However, my earlier print had at launch rod lug. Trying to decide if I try to cut that off and sand (or maybe patch the hole with epoxy).
Keeping it gives you options later.
What motor are you going to fly this on?
And didn't you make it with room for eight 13 mm engines? 8×A10 would make it really zippy.
Also I have heard that clusters are a PITA...
Pretty addictive watching Octoprint (although I need some lights for my enclosure)...
View attachment 541905
My one enclosure is not transparent, but Ironically it is all white so its the only one that shows a picture when lights are out (due to glow of LCD reflecting off white interior walls).Yeah, same here. Funny thing is my printer is about 5 feet behind me while I stare at the OctoPrint stream.....
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