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Two words: penetrating epoxy. Let the whole thing become a wood fiber composite.
finally got the 2 launch lugs glued on the 40 year old Delta II rocket. Took me 2 weeks to work up the interest. Depression is the pits.
Which pyro? Quickburst?I made 70 more conductive igniters and started soldering some egg timers.
I've got a Paulownia tree in my parents yard (yes, it's my tree, lol) that's starting to die and drop branches. The leaves are huge, the seed pods are fun to the play with, and the wood is very light. Never noticed the fire resistance in bonfires, though.
Which pyro? Quickburst?
So, aside from balsa and basswood what other timbers do we see in model rocketry?
And also pull the CP down further. Watch you don't end up overstable.I looked at the fins this morning and thought the same thing. A real danger of fin flutter. I decided to box the fins in. I'm going to attach a 1/8" x 6"x 4' length of plywood from each fin tip to fin tip.. I think it will make the fins more ridged.
I'll have to go read the build thread. As with so many of your designs, it has me worried, but your track record of success shows that I worry too much.Just about done working through the design of this scratch build 1/150 scale Saturn V.
4 stages, 12 BP motors and spin stabilization via canted 1st stage fins.
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Naturally, any time I see a letter followed by a number as a single "word", my mind goes directly to motor designations. A full E6000 would have a burn time of about 6.7 ms.took some playing cards to use as spacers for the clear fins on the Delta II, this will hold the fins in position while the E6000 dries. going to wait till tomorrow so that the launch lug glue dries fully.
As well you should be.All in all... yeah... I am sort of pleased with myself...
So, aside from balsa and basswood what other timbers do we see in model rocketry? I recall Sky Rockets used Tung wood in their Condor kit and I was impressed with the hardness and lightness of that.
As with so many of your designs, it has me worried, but your track record of success shows that I worry too much.
Many years ago I made a wing for a racing kart from a piece of Alaska yellow Cedar. The table my keyboard is resting upon is another trip down memory lane, wood alley.Pine and redwood. Pine is very cost effective and easy to find here. Redwood, just because I have a bunch of old posts from a fence we demolished. Redwood is actually lighter than Basswood.
I just threw this chart together to compare various wood types... I was surprised that bamboo is the clear winner, comparing strength to weight.
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Paulownia is often advertised in the breathier seed catalogs ("Get 85 pounds of blueberries from a single bush!!") because it grows fast. Like a 50cm diameter trunk in 10 years fast. It also fixes nitrogen, so it's probably not terrible for the soil despite that growth rate. They do leave a fair amount of litter (seed pods, small branches, etc.) in addition to the leaves. Environmentally, it's probably a net positive over balsa since it's not a tropical rain forest tree.Thanks for that. It's a really interesting timber, referred to as 'The Aluminium of timber' and 'The World's Most Sustainable Timber'. Looking into both of those claims today.
So, aside from balsa and basswood what other timbers do we see in model rocketry? I recall Sky Rockets used Tung wood in their Condor kit and I was impressed with the hardness and lightness of that.
We prototyped bamboo ply (cuts beautifully with laser) fins in a few rockets and now that I want to make them into kits I can't source the bamboo at a realistic price. #ofcourse
So impressed I contemplated moving all our kits to laser-cut bamboo fins. But that ain't gonna happen...
I just threw this chart together to compare various wood types... I was surprised that bamboo is the clear winner, comparing strength to weight.
I'm going to box the fins in. That should firm up the fins. And hopefully control some of the fin flutter I'm worried about. I have toyed around with some ideas to add base drag. I was looking at it today and thinking it will need pounds of nose weight. I have also been thinking about a smaller version to check if I can make it stable. I plan to fly it in March at our SpringFest. So, I have time to work out the bugs. Ideas are welcome.And also pull the CP down further. Watch you don't end up overstable.
Curled or curved fins are naturally stiffer and resist flutter. I've used 0.025 PETG plastic fins made from shipping tube on a 2 oz model with a C6 motor and had no apparent flutter.I'm going to box the fins in. That should firm up the fins. And hopefully control some of the fin flutter I'm worried about. I have toyed around with some ideas to add base drag. I was looking at it today and thinking it will need pounds of nose weight. I have also been thinking about a smaller version to check if I can make it stable. I plan to fly it in March at our SpringFest. So, I have time to work out the bugs. Ideas are welcome.
Dave
I'm going to box the fins in. That should firm up the fins. And hopefully control some of the fin flutter I'm worried about. I have toyed around with some ideas to add base drag. I was looking at it today and thinking it will need pounds of nose weight. I have also been thinking about a smaller version to check if I can make it stable. I plan to fly it in March at our SpringFest. So, I have time to work out the bugs. Ideas are welcome.
Dave
Streamers? You mentioned toilet paper rolls playing out, which was obviously a joke, but what about painted tubes and mylar streamers made to look like paper?I had considered using 1/8th ply to box in the fins on the Port-O-Potty. It wasn't ridged enough. I'll try 1/4" instead. I'm thinking about adding a lot of base drag. Just haven't come up with a solid idea yet. Foam balls. Cones. Angled slats. I'm really going to have to make a smaller one to try this stuff out. Anybody have a suggestion?
Along similar lines, you could make angle out of 1/4" or maybe even 1/8" plywood, maybe 2" of vertical and 1/2" or horizontal, to stiffen it and add drag at the same tile.Curled or curved fins are naturally stiffer and resist flutter. I've used 0.025 PETG plastic fins made from shipping tube on a 2 oz model with a C6 motor and had no apparent flutter.
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