Aerotech I285R motors

Several of us have had some problems with early ejection using the I285R motors. I mean waaaaay early, after about 1 to 2 seconds of boost.
We checked the Aerotech site and are using the recommended delay element for a medium delay.
So far (after a few months) Aerotech has not responded on this problem.
Is anyone else experiencing this? Has Aerotech changed the delay element?
Don Brown NAR Level 2
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Don Brown wrote:

Don,
Please file a MESS report at http://nar.org/NARmessform.html so we can track these issues. The date code located on the instructions is really important to determine if there is a lot or systemic problem with the motor.
John Lyngdal NAR S&T Secretary
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Don Brown wrote:

A couple of thoughts:
Are you certain that early ejection is the cause? Whenever I hear someone blame early ejection and it is happening just about the time of motor burnout, I think that drag (or inertial) separation should be considered first. But you probably already did but failed to mention it.
How were the delay elements stored? If they are not kept tightly sealed and away from propellant grains of Blue Thunder and Red Line reloads, migration of burn rate catalyst will result in shortened delays. You might have noticed that the warranty statement on the reload instructions now has a provision where the warranty is void if you assemble the motor more than a few hours (I forget exactly how many, twelve springs to mind.) before using it.
--
David W. Schultz
http://home.earthlink.net/~david.schultz /
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
There have been several rocketeers at our launches with delays from Redline reloads not working properly. Nothing to the extent Don mentioned, but yes, they have been a second or two, or three early.
-Booms
TRA L3

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
One, two or even three seconds would be within the permissible variation for rocket motor pyrotechnic delays, depending on the specific delay time (+/- 20% or 1.5 seconds, whichever is greater).
Gary
--
Gary Rosenfield
President, AeroTech Consumer Aerospace
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Agreed. Drag or pressure differential separation are the two most common causes of "early deployment" in HP rockets, especially when observed near motor burnout.
Gary
--
Gary Rosenfield
President, AeroTech Consumer Aerospace
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.