Lift capability...

[Varmint]

OK, My question is hopefully a simple one.

 

While I understand and appreciate the start-to-finish aspect of spinning my own fireworks, has anyone quantified lift capability of say the Estes motors with "standard" pryo motors?

 

It seems to me months/years/decades can be spent mastering motors, and of course the same could be said for headers.

 

So, I'm interested in determining lift capability. I know for a fact an Estes a10-3t can lift a 2" ball to a safe height, can anyone help quantify what a B, C, D, E series can do?

 

Here's the backstory: I spent weeks/months really working with a buddy, we worked on motors, stars, reports, exhaust sparks, burst sparks (titanium of course), but in the end we had 5 hand-crafted objects of intense desire, only one of which ended up giving what would be considered "professional" appearance.

 

If we could change focus to burst and effect, THEN circle back to motors, I think we'd both end up more interested.

 

So, is there a "shortcut" that leverages factory repeatability so we can focus on the truly interesting part of the display?

 

To the purist, I'm certain this comes off as heresy incarnate, but as an engineer, I'm taught variable reduction is core to progress...

 

Be gentle...

 

DAS

[nater]

I would check out the thrust curves available from Estes. Shoot for an 8/1 or 10/1 thrust to total weight ratio.

 

Are you using the delay of the motor to ignite the heading? If so, you will need to consider the delay time as well. The delay time depends on the size / shape of the header and the desired effect. Do you want the shell displayed at apogee or while rising or falling?

 

Personally, I would work on the motors first, but I enjoy working on motors more so than headers. What is most important is that you enjoy your work.

 

Edit to add: Estes motors are low powered end burners and will have a limited lifting capacity. Core burning BP motors where most pyros start have a much higher thrust and can lift heavier headings. When you start getting into hybrid and whistle motors, the lifting capacity is very impressive.

 

Peret here along with Dagabu have developed a nifty thrust stand with good software to help predict flights. PM peret and search threads for the Acme Test Stand. I am sure it would satisfy the engineer in you.

Edited January 31, 2014 by nater

[Varmint]

nater:

 

Thanks for the feedback. Yes, I followed as many of the threads as I could find on the test stand, and probably having every single piece of hardware but the strain gauge, I'd probably build my own for the fun of it rather than purchase.

 

I would have written off Estes as too expensive, but once I saw they had classroom bulk packs for $2.61 each (C6-5) I thought they might make a nice interim solution.

[mabuse00]

I dont have experience with the original Estes motors, but I tried similar ones.

 

In my country you can't buy motors with more the 20g propellant without a license, and the small ones are barely suited for more than little salute rockets.

C6-5

 

Five second delay is optimal for modelrockets but to long for our needs (in most cases). Look out for the 3 second variant.

C6-3 should be fine with 120g AUW.

 

 

So, is there a "shortcut" that leverages factory repeatability so we can focus on the truly interesting part of the display?

Work with shells and mortar Most people find that easier.

[PyroCube]

Sorry for OT, but how much weight can a well built 15mm coreburner lift?

 

 

Greets

[Arthur]

I understand the variable reduction aspect, probably that's one of the reasons why people make shells. All the rocket variables go immediately and also there is no stick to return to earth causing damage.

[nater]

Sorry for OT, but how much weight can a well built 15mm coreburner lift?

 

 

Greets

Type of fuel? Nozzle? Spindle design - traditional BP or Hybrid-Universal? Pressed or Rammed?

 

There are too many variables to give the best advice. A 2" ball shell should be doable with a BP motor and nozzle. Whistle and hybrid rockets can lift more.

[Varmint]

I've lifted reports by drilling (drill bit wrapped with tape turned by hand) into the clay, past ejection, and most of the way through the delay, so the timing, while not perfect does end up near the natural apogee which was the goal.

 

But I do like the idea of just changing to shells, I have to admit. I love the noisy and sometime spark-filled exhaust tail against the night sky, the rocket is "niftier", but changing to shell with lift charges is a pretty obvious shortcut to concentrating on the actual display.

 

This is why I ask questions, sometime the obvious is occluded if you set your parameters too narrow from the start.

[PyroCube]

Type of fuel? Nozzle? Spindle design - traditional BP or Hybrid-Universal? Pressed or Rammed?

 

There are too many variables to give the best advice. A 2" ball shell should be doable with a BP motor and nozzle. Whistle and hybrid rockets can lift more.

 

Sorry, I meant a traditional BP (60/30/10, ballmilled) coreburner. I don`t know the exact measurements of the tooling but I think the spindle is

about 5mm in diameter and 120mm in lenght. I think a 2" shell is a bit to small for such a motor, I can easily lift a 2" shell with a 15mm endburner so I

suppose the coreburner can lift two or three 2" shells, maybe even a 3"...

 

Greets

[Peret]

If the published motor data includes the impulse and burn time, you can use the Acme software to create a simulated burn. Then the other features of the software can be used to estimate lift power and height. You can download the software here:

https://www.dropbox.com/s/6u3aak66se60a42/RocketTestSetup301.exe

I don't charge for it. Play with the Simulator function. It allows you to model the thrust curve shape for different kinds of motor (end burn, core burn).