Help Support RocketryForum by donating using the link above or becoming a Supporting Member.


Results 1 to 8 of 8
  1. #1
    Join Date
    19th June 2017
    Location
    Vacaville, CA
    Posts
    425

    Aerotech I364FJ grain

    I'm assembling an Aerotech I364FJ in my 38/720 case. 5 of the 6 grains are wrapped separate and are identical. The 6th unwrapped grain has one end cut flat, just like the other grains.

    The other end has a slight concave edge and is coated with what appears to be epoxy.

    My question is why is it not cut flat and coated. And where does that grain go in the assembly. The directions make no mention of different grains.

    Thanks.Click image for larger version. 

Name:	0109180652.jpg 
Views:	154 
Size:	73.4 KB 
ID:	335826Click image for larger version. 

Name:	0109180652a.jpg 
Views:	165 
Size:	76.3 KB 
ID:	335827Click image for larger version. 

Name:	0109180653.jpg 
Views:	177 
Size:	66.5 KB 
ID:	335828Click image for larger version. 

Name:	0109180711_HDR.jpg 
Views:	145 
Size:	109.3 KB 
ID:	335829Click image for larger version. 

Name:	0109180711.jpg 
Views:	140 
Size:	81.0 KB 
ID:	335830

    Sent from my VS988 using Tapatalk

    Eric Hamilton, NAR, TRA
    SARG, LUNAR
    Level 1, Estes Argent, H115DM
    Level 2, Scratchbuilt 2.6", J270G

  2. #2
    Join Date
    15th November 2011
    Location
    Mukwonago, WI
    Posts
    556
    Quote Originally Posted by Eric View Post
    I'm assembling an Aerotech I364FJ in my 38/720 case. 5 of the 6 grains are wrapped separate and are identical. The 6th unwrapped grain has one end cut flat, just like the other grains.

    The other end has a slight concave edge and is coated with what appears to be epoxy.

    My question is why is it not cut flat and coated. And where does that grain go in the assembly. The directions make no mention of different grains.

    Thanks.Click image for larger version. 

Name:	0109180652.jpg 
Views:	154 
Size:	73.4 KB 
ID:	335826Click image for larger version. 

Name:	0109180652a.jpg 
Views:	165 
Size:	76.3 KB 
ID:	335827Click image for larger version. 

Name:	0109180653.jpg 
Views:	177 
Size:	66.5 KB 
ID:	335828Click image for larger version. 

Name:	0109180711_HDR.jpg 
Views:	145 
Size:	109.3 KB 
ID:	335829Click image for larger version. 

Name:	0109180711.jpg 
Views:	140 
Size:	81.0 KB 
ID:	335830

    Sent from my VS988 using Tapatalk
    More than likely that grain was the bottom end when AT casted the grains. The smooth surface is likely from the cap AT used. That's what the other grain surfaces would look like if AT didn't cut the grains to size.

    Preston

    Preston Nobile
    TRA #6025 L3
    Top Flight Recovery LLC
    topflightrecoveryllc@gmail.com

  3. #3
    Join Date
    21st January 2009
    Location
    Penns Creek, PA
    Posts
    7,023
    Thats normal. Its the bottom grain from the casting. I usually put those concaved ends on the bottom by the nozzle.

    Sent from my SAMSUNG-SM-J326AZ using Rocketry Forum mobile app
    ************************************************** ***************************
    Total Impulse for 2018: 0 - Would love to fly a L1000
    Total money for MOAR IMPULSE: $0

  4. #4
    Join Date
    19th June 2017
    Location
    Vacaville, CA
    Posts
    425
    Sounds good. That's what I ended up doing.

    Sent from my VS988 using Tapatalk
    Eric Hamilton, NAR, TRA
    SARG, LUNAR
    Level 1, Estes Argent, H115DM
    Level 2, Scratchbuilt 2.6", J270G

  5. #5
    Join Date
    6th December 2013
    Location
    TX
    Posts
    2,273
    Yeah, I had a similar grain in a 38mm KBA I motor about 2 years ago. Pretty sure I mentioned it to Karl at Aerotech and he confirmed what the others have said above. Wound up installing it in the bottom and it worked just fine.

    The Fastest and Most Reliable and Transparent Way to Buy High Power Rocket Motors

    Same/Next Day Shipping, Real Time Inventory, Order Confirmation, Package Tracking

    Tripoli #3135

    Confirmed OG
    Level Too

  6. #6
    Join Date
    19th January 2009
    Location
    Pine Mountain, Ga
    Posts
    2,162
    Quote Originally Posted by Eric View Post
    I'm assembling an Aerotech I364FJ in my 38/720 case. 5 of the 6 grains are wrapped separate and are identical. The 6th unwrapped grain has one end cut flat, just like the other grains.

    The other end has a slight concave edge and is coated with what appears to be epoxy.

    My question is why is it not cut flat and coated. And where does that grain go in the assembly. The directions make no mention of different grains.

    Thanks.Click image for larger version. 

Name:	0109180652.jpg 
Views:	154 
Size:	73.4 KB 
ID:	335826Click image for larger version. 

Name:	0109180652a.jpg 
Views:	165 
Size:	76.3 KB 
ID:	335827Click image for larger version. 

Name:	0109180653.jpg 
Views:	177 
Size:	66.5 KB 
ID:	335828Click image for larger version. 

Name:	0109180711_HDR.jpg 
Views:	145 
Size:	109.3 KB 
ID:	335829Click image for larger version. 

Name:	0109180711.jpg 
Views:	140 
Size:	81.0 KB 
ID:	335830

    Sent from my VS988 using Tapatalk
    It is an end, doesn't matter where it goes as there is plenty of space between grains.

    Sent from my Pixel XL using Rocketry Forum mobile app
    Christopher Short
    TRA #10247 L3 TAP
    NAR #83000 L3CC
    Prefect #38
    Chris' Rocket Supplies, LLC
    www.csrocketry.com
    sales@csrocketry.com
    850-554-6531

  7. #7
    Join Date
    18th January 2009
    Location
    Fort Myers, FL
    Posts
    3,492
    When I assembled HPR AT motors, I always put the single exposed grain at the nozzle end of the motor. Having fresh propellant at the top makes for a more hassle free ignition.

    I have one of these motors in my box that I never got to fly.
    Donald Besaw Jr.

    Total flights for 2018 - 0

  8. #8
    Join Date
    19th June 2017
    Location
    Vacaville, CA
    Posts
    425
    I assembled it with the exposed end grain next to the nozzle. The weather wasn't great at Snow Ranch. So I will fly it February 3rd.

    Eric Hamilton, NAR, TRA
    SARG, LUNAR
    Level 1, Estes Argent, H115DM
    Level 2, Scratchbuilt 2.6", J270G

Similar Threads

  1. [For Sale] AT I364FJ-M reload for sale
    By Donaldsrockets in forum Yard Sale / Wanted
    Replies: 0
    Last Post: 19th January 2015, 06:12 AM
  2. [Wanted] Used Aerotech 54 mm motor grain liner
    By Kehoes23 in forum Yard Sale / Wanted
    Replies: 3
    Last Post: 16th June 2014, 11:33 PM
  3. Aerotech Delay Grain Burnrates
    By rocketsaway in forum Propulsion
    Replies: 13
    Last Post: 17th January 2014, 03:52 AM
  4. Shortening An Aerotech Delay Grain
    By Uncrichie in forum Recovery
    Replies: 11
    Last Post: 30th November 2009, 04:17 PM
  5. Aerotech Grain Spacers
    By C.O.B.H.C. in forum Vendor Display
    Replies: 36
    Last Post: 14th October 2009, 06:41 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •