Estes E jection charge

[Mx2]

Scratch built rocket. Looking at an E – Estes Black powder motor. Is there a way to reduce the ejection charge (don’t need as much powder in there ) and allowed to take it to a sanctioned club launch?

 

[GlenP]

Rather than modifying the engine, you could maybe add a baffle and/or a small vent to reduce some of the pressure but still push out the nose and chute? Do you have pictures of the particular rocket?

 

[Mx2]

Rather than modifying the engine, you could maybe add a baffle and/or a small vent to reduce some of the pressure but still push out the nose and chute? Do you have pictures of the particular rocket?

Reply appreciated. Hmmm.. just theory in pieces on garage floor tonight so no picture. I got poking around on Estes motor and not very powder reducing friendly. I’m thinking now ordering 24mm single use composite and reducing powder in ejection charge. Although your side vent idea is possible and could add that in on build so either type motor could be used. Hmmmm…

 

[Antares JS]

Why are you trying to reduce the ejection charge? It's really not a problem to have more ejection charge than you need. Having less ejection charge than you need causes a lot more problems.

 

[afadeev]

Scratch built rocket. Looking at an E – Estes Black powder motor. Is there a way to reduce the ejection charge (don’t need as much powder in there ) and allowed to take it to a sanctioned club launch?

Not really - modifying Estes motors will (theoretically) negate their certification status.
How much of a BP charge are you aiming for?

Alternatively, you could fly on AeroTech 24mm motors (e.g.: E11, E28, F24, F29) and control both the delay timing and ejection charge size.
Or, add design elements into your rocket to muffle (baffle, but it adds weight and requires space) or disperse (vent holes in the airframe, but requires careful calibration) the ejection charge of the standard Estes motor.

a

 

[Mx2]

Looking on Internet I found the Aerotech E20-8 24mm which should work. The Estes E- with vent holes is complexicuted when all I need is reduce the charge. My rocket design requires less charge for ejection. I read that one can remove red cap, dump out excess, cover with filler (dog-barf) tape over. But was curious regarding Estes black powder.

 

[Antares JS]

My rocket design requires less charge for ejection.

Why? I have never heard of a design for which it would be bad to have too much ejection powder.

It seems to me that removing a portion of powder is a needless risk. You are risking not having enough powder to eject your recovery device. Meanwhile leaving the charge as-is with some extra powder gives you some safety margin if your nose is tighter than expected or some such.

 

[Mx2]

Not really - modifying Estes motors will (theoretically) negate their certification status.
How much of a BP charge are you aiming for?

Alternatively, you could fly on AeroTech 24mm motors (e.g.: E11, E28, F24, F29) and control both the delay timing and ejection charge size.
Or, add design elements into your rocket to muffle (baffle, but it adds weight and requires space) or disperse (vent holes in the airframe, but requires careful calibration) the ejection charge of the standard Estes motor.

a

Thank you for the reminder that reducing ejt-charge in Estes is not acceptable for sanction launch. That was info I needed. I will read up on the Aeroteck 24mm sizes. Thank you for your direct answer and suggestion.

 

[dpower]

No “theoretically“ about it. Trying to remove any material from an Estes BP motor *will* render the motor uncertified.

 

[Ronz Rocketz]

The E12-4 has more like a 2.5s delay, rarely 5.5s but can happen. Did you sim the rocket? What delay did the sim suggest?

I was able to sim a 100" rocket with a 3" tube and E12 that suggested 0.75s delay so it's possible but it lawndarted.