Alternative to B14-0?

[Vonskii]

So I'm thinking of making an old 3 stage ring fin rocket from the Estes designer of the month contest. It was the September 1976 winner, designed by Bob Dinsmore, a real fantastic looking model. The only problem I can see before building is the utilization of B14 motors on the first 2 stages. These motors had a crazy thrust curve , with a rapid peak of 7 pounds max thrust and finishing in half a second. Sadly they aren't available anymore, and I'm wondering what modern alternative I should use instead?

I took a look at some modern Estes engines to try find something similar, and figured the C11-0 might work. The D12-0 has a similar rise and peak, but keeps burning for more than a second after the B14. I'm also not sure how weight of the motor would factor in. I've never used motors outside of Estes, so I'm a little lost as to what alternatives would be available. Any help would be appreciated! I've attached the plan and B14 thrust curve.

 

[SolarYellow]

Model the rocket in OpenRocket.

 

[Vonskii]

Model the rocket in OpenRocket.

I would, but my understanding was that ring fins didn't functionally model in OpenRocket, just visually? If that works though I'd most definitely model it!

 

[lakeroadster]

Cool design... thanks for posting this!

Here's some interesting data related to B14's....

https://www.rocketryforum.com/threads/estes-b14.141361/

 

[Vonskii]

Some interesting data related to B14's....

https://www.rocketryforum.com/threads/estes-b14.141361/

Thanks, I was actually reading this earlier. Interesting to see how the big 18mm motors from Estes and Centuri back in the day kind of migrated to 24mm, leaving the 18mm with nothing with that kinda "oomph" nowadays. I would have loved to see those motors in action back then, just some crazy fast forces!

 

[cerving]

Make the bottom stage 24mm and use a D12 or E12, to two C6's. That will do it.

 

[Vonskii]

Make the bottom stage 24mm and use a D12 or E12, to two C6's. That will do it.

Thanks for the input! I might just make both the stages 24mm, and add an engine adapter in the second stage to use the C6-0. that way if it does need something bigger after the first flight, I don't have to remake a whole stage.

 

[Neutronium95]

Thanks, I was actually reading this earlier. Interesting to see how the big 18mm motors from Estes and Centuri back in the day kind of migrated to 24mm, leaving the 18mm with nothing with that kinda "oomph" nowadays. I would have loved to see those motors in action back then, just some crazy fast forces!

There are plenty of punchy 18mm motors with a lot of oomph these days. Unfortunately they're all APCP and are thus unsuitable for direct staging.

 

[mbeels]

I took a look at some modern Estes engines to try find something similar, and figured the C11-0 might work.

Make the bottom stage 24mm and use a D12 or E12, to two C6's. That will do it.

The C11-0 is a good first stage with less impulse than a D, and more kick than a C6.

 

[lakeroadster]

I would, but my understanding was that ring fins didn't functionally model in OpenRocket, just visually? If that works though I'd most definitely model it!

You can indeed use a "Hack" to model those ring fins within Open Rocket. Here's more data on that:

https://www.rocketryforum.com/threads/simulation-of-ring-fin-designs-in-open-rocket.167337/​

 

[dpower]

I built a Centuri T-Bird clone and configured the 1st stage for 24mm, and the C11-0 works great. When I build my Farside-X, I’ll do the same thing, though it’ll be a little tougher since it’s minimum diameter.

 

[SolarYellow]

C11 is great for staging due to the ultra-short burn time. It gets things moving and the second stage going before there's much time for anything to go wrong.