Flyfalcons
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Here's a project I've been working on that's just about ready to go. The Estes Ninja #0882 was my third or fourth rocket, and the first one flown that I actually got back. It wasn't in my stash of rockets that were kept from my childhood, so it must have had a short life or been retired early. I do remember it though, in that it was really cool looking! Inspired by EXPjawa's BT-70 upscale (see here), and with most of a Designer's Special sitting on my work bench, I decided to design a BT-60 upscale for 24mm power.
My design goals were as follows:
1) Closely resemble the original Ninja in BT-60 size, which is 222% of the original size.
2) Light enough for small field flights with a C11-5
3) Strong enough for an F44-8 for a real Ninja-like experience
4) Prevent the pointy fins from constantly taking damage on landing
What I ended up with is as follows. My original drawings from the standard Ninja have a slightly longer body tube and shorter nose cone. However, from the four BT-60 cones I had, the only one that was pointy enough to look good is 8-3/8" long, instead of the 6-3/4" that I was shooting for. So I had to compromise and shortened the body tube by 3/4" from true upscale. The result, I think, looks just fine. The base of the nose cone is pretty straight, so if you ignore the actual joint, the outline is still pretty close to original. This cone, by the way, came from the Estes BT-60 nose cone 3-pack assortment and not the Designer's Special.
To prevent fin damage, and to help withstand the 475mph shot from an F44-8, I selected 3/32" plywood for the fins. They are mounted through the wall in a simple arrangement: There is no middle centering ring on the MMT, just a forward and aft. The front of the fin tabs press against the forward CR. They are glued on with epoxy, no internal fillets, and wood glue for external fillets to help keep the aft weight down. The fins sit pretty far forward, and I moved the aft location from a true upscale 2.22 inches from the bottom of the tube back a little to 2 inches to help with CG issues. The fins themselves are a true 222% size and shape.
I included an engine block for flying with Estes C, D and E black powder engines, and a 24mm retainer for using composite motors. I set the engine block so a D12 with E spacer overhangs the MMT by 3/8". The bottom of the MMT sits flush with the bottom of the BT, then the inner retainer ring is glued on and overhangs the body tube by a small amount.
According to the simulation, 1 ounce of nose weight is needed to keep stable with the heaviest of the engines I may wish to use.
3/16" launch lugs were deemed appropriate for this size and weight rocket. I like using dual short launch lugs so that's what is on the sim.
That's pretty much it. This is a 3FNC design that just happens to look pretty cool. As can be seen in the simulation, performance should be great. A D12-5 should send it to 800 feet, an E20-7W goes to 1500, and an F44-8W should teleport the Ninja to 1660 feet. All while safely flying on a C11-5 to 360 feet at small fields. Before I left for my trip yesterday, I had basic construction complete. I just need to fill, smooth, paint, and add Stickershock vinyl decals and nose weight. Hoping to fly this at a local launch on the 17th this month, but I only have a few days at home between now and then so hopefully I can pull that off. Enjoy and hopefully someone can use the plans to make one of their own.
View attachment Estes Ninja BT-60 Upscale.ork
My design goals were as follows:
1) Closely resemble the original Ninja in BT-60 size, which is 222% of the original size.
2) Light enough for small field flights with a C11-5
3) Strong enough for an F44-8 for a real Ninja-like experience
4) Prevent the pointy fins from constantly taking damage on landing
What I ended up with is as follows. My original drawings from the standard Ninja have a slightly longer body tube and shorter nose cone. However, from the four BT-60 cones I had, the only one that was pointy enough to look good is 8-3/8" long, instead of the 6-3/4" that I was shooting for. So I had to compromise and shortened the body tube by 3/4" from true upscale. The result, I think, looks just fine. The base of the nose cone is pretty straight, so if you ignore the actual joint, the outline is still pretty close to original. This cone, by the way, came from the Estes BT-60 nose cone 3-pack assortment and not the Designer's Special.
To prevent fin damage, and to help withstand the 475mph shot from an F44-8, I selected 3/32" plywood for the fins. They are mounted through the wall in a simple arrangement: There is no middle centering ring on the MMT, just a forward and aft. The front of the fin tabs press against the forward CR. They are glued on with epoxy, no internal fillets, and wood glue for external fillets to help keep the aft weight down. The fins sit pretty far forward, and I moved the aft location from a true upscale 2.22 inches from the bottom of the tube back a little to 2 inches to help with CG issues. The fins themselves are a true 222% size and shape.
I included an engine block for flying with Estes C, D and E black powder engines, and a 24mm retainer for using composite motors. I set the engine block so a D12 with E spacer overhangs the MMT by 3/8". The bottom of the MMT sits flush with the bottom of the BT, then the inner retainer ring is glued on and overhangs the body tube by a small amount.
According to the simulation, 1 ounce of nose weight is needed to keep stable with the heaviest of the engines I may wish to use.
3/16" launch lugs were deemed appropriate for this size and weight rocket. I like using dual short launch lugs so that's what is on the sim.
That's pretty much it. This is a 3FNC design that just happens to look pretty cool. As can be seen in the simulation, performance should be great. A D12-5 should send it to 800 feet, an E20-7W goes to 1500, and an F44-8W should teleport the Ninja to 1660 feet. All while safely flying on a C11-5 to 360 feet at small fields. Before I left for my trip yesterday, I had basic construction complete. I just need to fill, smooth, paint, and add Stickershock vinyl decals and nose weight. Hoping to fly this at a local launch on the 17th this month, but I only have a few days at home between now and then so hopefully I can pull that off. Enjoy and hopefully someone can use the plans to make one of their own.
View attachment Estes Ninja BT-60 Upscale.ork