And it's a buck cheaper than the discontinued discount price in the other page. :eek:

Looks like the Discontinued kit is the original 18mm powered version with balsa fins.
The other, cheaper My Boid kit seems to be an updated version that is 13mm powered with fiber fins that 'lock' in to the pre cut fin slots, making it an ever better beginners kit.
I think this honors the original intent of Carl who I think provided a lot of these kits to youth groups...now cheaper, easier to assemble, less likely to be lost by flying on 13mm, still with different fin shapes so more fun for beginners, etc

That is correct. I've been working with Randy on this project, and I've modeled the fin shapes in OR, I just need to finish on all the different nosecone combos.

That's similar to something I've advocated for with Estes, BMS, and later SEMROC for the last 20 years. I wanted 13mm power, not for altitude, but because an A3-4T is cheaper and the delay is better for a BT-50 bulk rocket. Due to smaller components and smaller engine casing and better delay, the A3 or A10 will fly higher than an A8-3.

The big difference would be the fin shape. The best fin shape for schools, youth groups would be something that has a slightly negative sweep on the trailing edge to prevent fin breakage on landing. The landing forces would be absorbed by the motor and transmitted to the whole motor mount system instead of one easily broken swept fin. My Boid, while cheap and easy to assemble, will suffer fin damage early and often. This means a classic motor hook is needed, not the extended finger hooks. Or just friction fit. :)

I agree that negative swept fins, especially on streamer recovery models are much more desirable. I would fly my estes Zinger, with the narrow swept back fins on C6-7's & would break a fin every time, ended up with gobs of epoxy on them. And with the Zinger, just a few thin strips of masking tape over the end of the body tube and the exposed end of the motor mount was plenty for motor retention, no hook needed.
But I think with the combination of the lighter 13mm motors, and the more durable fiber fins, (unless the fin shape is very narrow/pointy/thin) that the fins in most cases may be fine for the updated My Boid.

That new variation of the My Boid is an interesting idea. An ST-8 sized model with a 13mm mount is a nice size combination, too.

The 1" plastic flagging streamer on the original was pretty ineffective (I managed to get one with the fins and nose cone that pretty much match the artwork still being used) and it sometimes needed repair.

Seems silly to reuse the same catalog number, though, as it clearly leads to confusion.

At that price point the new My Boid will be a worthy competitor to the BMS School Rocket. I'll have to get a couple to try out for some future MoF-related projects.



As an aside to tbzep - I have some Alpha with FireFly altimeter data on various A motors including the A10 and A3 (these using the plastic adapters JumpJet designed) and there is no real performance advantage, in that case, for the 13mm motors. Having a smaller motor mount and needing no adapter would save enough mass to make it matter some, I expect.

I've routinely seen a considerable difference in altitude with A8-3 and A8-5 in calm air. The Generic E2X kits will hit peak and start down with the A8-5, but the A8-3 is still ascending at ejection. It's easy to see, but the actual difference in altitude might be within the margin of error of an altimeter. With wind, they both will hit peak and the A8-5 will descend a long way before ejection. The A3 wouldn't have enough kick off the pad to take advantage of the 4 second delay with the Generic E2X, but might with a light bird.

At any rate, the big advantage of the 13mm mount is a 4 pack of A3-4T's is the same price as a 3 pack of A8-5's. The A8-3 is way too short a delay for any of the BT-50 sized bulk kits, so you can't take advantage of the bulk pack discount. That's another thing I've wanted Estes to do for years...bulk pack A8-5's. Bulk pack A8-4's would be even better. :)

To clarify a bit on what I said earlier. There is enough scatter in the data (perhaps 20 flights on A8-3s, A8-5s and A3-4Ts primarily) that motor-to-motor and specific launch condition differences appear to obscure anything clearly favoring the A3-4Ts. These were flights made over several months at two local sites all with the same weary Alpha. The Alpha was built from a circa 2010 bulk pack kit, and flying the same FireFly. (The FireFly and other current PerfectFlite altimeters are very consistent - which is, I am sure, the main reason they are the current TARC altimeters).

I agree the nominal 3 second delay is too short for these models and it would be great if Estes brought back the A8-5 bulk packs. They did exist at one time - I got one early in my BAR period though I don't recall the source now.

For that matter bulk A3-4Ts would be nice to have.

The Semroc Aphelion shows as discontinued but still shows up on the Semroc main page (along with the Saturn 1B). Maybe e-rockets will reconsider discontinuing this one. IT IS Semroc history and I wish they would keep it ... just because.

Me too!