Level 2 project: "Long Tom" LOC Cruiser -> stretched Tomahawk CM
- Thread starter Nytrunner
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Nytrunner
Pop lugs, not drugs
Nytrunner
Pop lugs, not drugs
Rocket is functionally ready, just needs paint now.
In one month's time, I'll drive to Pueblo!
Catch the sport flyer's meeting, do the rocketeer's reunion, hit up the banquet, watch presentations, etc...
I'm doing the weekend sport flying pass, since a day should be more than enough time to do an L2 right, and I can walk the range and relax the rest of the time.
If the banquet wasn't The Last Night, I'd leave early and go back to work, but since I'm there, I may explore a bit of Colorado too.
In one month's time, I'll drive to Pueblo!
Catch the sport flyer's meeting, do the rocketeer's reunion, hit up the banquet, watch presentations, etc...
I'm doing the weekend sport flying pass, since a day should be more than enough time to do an L2 right, and I can walk the range and relax the rest of the time.
If the banquet wasn't The Last Night, I'd leave early and go back to work, but since I'm there, I may explore a bit of Colorado too.
Nytrunner
Pop lugs, not drugs
For the first time pouring fillets with rocketpoxy, they didn't come out terrible.
I went through a bit of a discovery process:
1st set - 2oz mixed, didn't pay attention to how long I let it pre cure, scooped it in, formed it, turned out pretty good! Had WAY too much leftover mix
2nd set - 1.6oz mixed, during mixing I set a timer for 20 minutes........too long! It got very tough and noncompliant when laying the second fin of the pair. I stopped and had to touch it up with more later. Might take a dremel to bits of it too
3rd set - 1.4oz mixed, as soon as the hardener hit the resin, I set a timer for 16 minutes. Not bad, not bad, still getting a little tough towards the end
4th set - 1.4oz again, probably could have gone down to 1.2. Set a timer for 14 minutes and that was the perfect amount of workability.
Picture shows the......3rd and 4th sets? I'll go with that.
The cool thing about this process is your first rocket with a new technique gives you 3 or 4 opportunities to practice filleting!
I went through a bit of a discovery process:
1st set - 2oz mixed, didn't pay attention to how long I let it pre cure, scooped it in, formed it, turned out pretty good! Had WAY too much leftover mix
2nd set - 1.6oz mixed, during mixing I set a timer for 20 minutes........too long! It got very tough and noncompliant when laying the second fin of the pair. I stopped and had to touch it up with more later. Might take a dremel to bits of it too
3rd set - 1.4oz mixed, as soon as the hardener hit the resin, I set a timer for 16 minutes. Not bad, not bad, still getting a little tough towards the end
4th set - 1.4oz again, probably could have gone down to 1.2. Set a timer for 14 minutes and that was the perfect amount of workability.
Picture shows the......3rd and 4th sets? I'll go with that.
The cool thing about this process is your first rocket with a new technique gives you 3 or 4 opportunities to practice filleting!
A-N-D-R-E-W
Well-Known Member
Looking good! Love all the picture updates. I've never done fillets that were on a rounded surface, I'm sure it had its challenges
Nytrunner
Pop lugs, not drugs
Thanks! Here's to hoping they keep the fins on!
I did end up propping it on the fins so that the ends of the arc were about even.
But I have to give credit to using a filled epoxy like this. Let it sit for just a bit while you prep (set a timer!), and it just....stays where you put it. I want to try structural aeropoxy at some point, and maybe even home thickened epoxy later on.
(and of course thanks to all the threads I've read regarding bonding to plastics, surface prep, tape dams, etc...)
Nytrunner
Pop lugs, not drugs
Club member heard I wanted a 54mm red lightning. He said "I think I've got one, I'll check"
It was not the J355 I wanted.....
It was a K750
So! I no longer have to worry about weight, and this will be a true level 2 flight.
It was not the J355 I wanted.....
It was a K750
So! I no longer have to worry about weight, and this will be a true level 2 flight.
Tim51
Well-Known Member
Very cool indeed (and here's me - got my L2 over 2 years ago and still haven't flown anything bigger than a Pro 54 4G!)
What does that sim at, if you don't mind me asking?
Nytrunner
Pop lugs, not drugs
I want to say ~4800'.
It's a fat rocket with extra fin surface, so nothing seems screwy yet.
Now if it goes well, I'll get a DMS J and pop it in my level 1 rocket Big SAM, so I can say I've flown A-K this year.
An I303 put it to 3600 feet, so I'm wondering if I can pop it over a mile.
It's a fat rocket with extra fin surface, so nothing seems screwy yet.
Now if it goes well, I'll get a DMS J and pop it in my level 1 rocket Big SAM, so I can say I've flown A-K this year.
An I303 put it to 3600 feet, so I'm wondering if I can pop it over a mile.
Nytrunner
Pop lugs, not drugs
Finally nailed down the paint scheme.
I took red test round markings with the outlined warhead panels and whaleback gray/white color shift. Then I added my traditional blue accents and roll pattern nose.
It'll be a good match for Big SAM
I took red test round markings with the outlined warhead panels and whaleback gray/white color shift. Then I added my traditional blue accents and roll pattern nose.
It'll be a good match for Big SAM
Spiffy. I really like the fin can treatment. Will steal it one day.
Nytrunner
Pop lugs, not drugs
Lots of fin acreage to smooth. Bondo spot putty to the rescue once again!
Nytrunner
Pop lugs, not drugs
I feel that the leprosy phase is necessary to better appreciate the final product.
Besides, if someone's never used spot putty before, they deserve to know how it looks
Besides, if someone's never used spot putty before, they deserve to know how it looks
The ugly duckling transformation that rockets undergo before and after painting never ceases to amaze me. It took me a while to get comfortable with how awful things look after filling and sanding.
Nytrunner
Pop lugs, not drugs
Ordered some black vinyl striping on amazon to save time making the warhead panels.
Also painting large rockets in an apartment
requires some creativity.
Also painting large rockets in an apartment
requires some creativity.
Nytrunner
Pop lugs, not drugs
Sanding and paint cycle interrupted by an unexpected phonecall from home so I built a motor instead!
Decided I'd take one from Jim Jarvis' book and play it safe by sealing the closures in the liner with 5 min epoxy.
Decided I'd take one from Jim Jarvis' book and play it safe by sealing the closures in the liner with 5 min epoxy.
Nytrunner
Pop lugs, not drugs
Not much to show for awhile.
Painting schedule has begun
Painting schedule has begun
Nytrunner
Pop lugs, not drugs
Have to do something while paint dries....
The gray dots represent aerodynamic moment points at 450 ft/s.
The rearwards one is with an angle of attack where the wind is flowing parallel to the wings (as if it was a simple 4fnc with a tailcone).
The forward dot is with wind perpendicular to the wings. Quite a difference depending on roll angle.
Interestingly enough, OpenRocket produced a result smackdab in the middle of those. (It's a rectangular marker, but the angle skews it)
Pressure distribution map is just because it looks nicer than a gray tube
I'm going to run more flow cases at higher speeds (850 and 1250 probably) as well as a case with AoA at 45deg to the wings.
The gray dots represent aerodynamic moment points at 450 ft/s.
The rearwards one is with an angle of attack where the wind is flowing parallel to the wings (as if it was a simple 4fnc with a tailcone).
The forward dot is with wind perpendicular to the wings. Quite a difference depending on roll angle.
Interestingly enough, OpenRocket produced a result smackdab in the middle of those. (It's a rectangular marker, but the angle skews it)
Pressure distribution map is just because it looks nicer than a gray tube
I'm going to run more flow cases at higher speeds (850 and 1250 probably) as well as a case with AoA at 45deg to the wings.
Attachments
Nytrunner
Pop lugs, not drugs
Well, I fat-fingered the streamline spacing variable and accidentally created an order of magnitude more streamlines than planned.
After my computer stopped screaming, I got this pretty cool vortex model from the wingtips though!
Wind in the -Z direction
Having fun here
Last one tonight I swear
After my computer stopped screaming, I got this pretty cool vortex model from the wingtips though!
Wind in the -Z direction
Having fun here
Last one tonight I swear
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I don’t know how to interpret any of that but it looks cool. Can you explain what actions you would take (if any) based on your results?
Also what software is that?
Also what software is that?
Nytrunner
Pop lugs, not drugs
Post 82 is the real meat of my activities. Finding those aerodynamic moment points and comparing them to OR's CP results give me more data to consider when balancing the rocket.
I may choose to launch with the wings aligned with the wind based on these findings (as opposed to against the wind)
All the colors just look cool. Although on a side note, it's a neat way to see that the computation is at least adhering to the laws of fluid physics judging by the pressure and velocity differentials at the nose and wings and the presence of vortex behavior at the tips. Since the model exhibits some level of complexity that I'd expect in a real world system, it helps give me confidence in any CP related decisions I make based on it
edit: Forgot to answer. It's called Solidworks. It's primarily a solid modeling tool, but there's a number of plugins for engineering analysis and manufacturing aids. I enjoy cranking the CFD tool as high as my laptop can manage.
I may choose to launch with the wings aligned with the wind based on these findings (as opposed to against the wind)
All the colors just look cool. Although on a side note, it's a neat way to see that the computation is at least adhering to the laws of fluid physics judging by the pressure and velocity differentials at the nose and wings and the presence of vortex behavior at the tips. Since the model exhibits some level of complexity that I'd expect in a real world system, it helps give me confidence in any CP related decisions I make based on it
edit: Forgot to answer. It's called Solidworks. It's primarily a solid modeling tool, but there's a number of plugins for engineering analysis and manufacturing aids. I enjoy cranking the CFD tool as high as my laptop can manage.
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Nytrunner
Pop lugs, not drugs
Final paint and vinyl striping complete tonight.
Tomorrow I'll pull off the masking tape/paper and unveil the finished results. Or I'll put on some of the decals from the Quest Tomahawk I never used lol
Tomorrow I'll pull off the masking tape/paper and unveil the finished results. Or I'll put on some of the decals from the Quest Tomahawk I never used lol
Well Solid Works is very cool then. It does not look very happy with that nose cone? Or am I misinterpreting it?
As an *extremely* casual CAD user I most likely will never so much as touch a running copy of SolidWorks.I'm jealous of all you guys who both have it (or have access to it) *and* the expertise to use it.
In the meantime, eagerly awaiting the reveal of the painted model. I fully expect to see it festooned with DRM decals.
In the meantime, eagerly awaiting the reveal of the painted model. I fully expect to see it festooned with DRM decals.
Nytrunner
Pop lugs, not drugs
Lol, that's just a high pressure region at the end of the nose. If you look at the legend, you'll see that area is all over 15.2 psi. Since atmospheric is 14.7, it's really not too high at all really.
If I was being paid for any of this analysis, I'd set Red to be a danger threshold, but then the whole rocket would be dark blue and boring. Since this is for my own entertainment, I set the rainbow chart so it looks good, and that's about it. Maybe I'll tweak it so it doesn't look like my nose is in danger of being crushed.
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