AeroTech Product Bulletin 2008-1

[Garoq]

5/20/08

AeroTech Product Bulletin 2008-1: Forward Seal Disks Now Required For Use With Specific 54, 75 & 98mm RMS Reloads

As a result of field experience and customer feedback, AeroTech is now requiring the use of aluminum "forward seal disks" with current production reload kits intended for use with 54/1706, 75/5120 and all 98mm RMS™ hardware. The specific kits affected are:

54/1706 Motor Hardware
K185W, K550W, K1100T, K695R, K513FJ, K805G

75/5120 Motor Hardware
L1420R, M1297W, M2030G

98/2560-15360 Motor Hardware
K458W, K650T, K680R, K1999N, L952W, L1300R, L1500T, M1419W, M1600R, M2100G, M2400T, M750W, M1939W, M2000R, M2500T, N2000W

The 54mm seal disk was announced last year (P/N 54FSD) and has been required for use with all 54/2560 and larger reload kits, the 75mm disk (P/N 75FSD) is currently being used with all 75/6400 and 75/7680 reloads, and the 98mm disk (P/N 98FSD) is a new machined aluminum part that will replace the phenolic disk currently shipping with 98mm reload kit production.

A small percentage of customers using some of these reload kits have reported a "blister" forming on the exterior of the forward end of the motor case. The blister is caused by excessive heating due to a small amount of hot gas passing between the case and liner during motor operation. In addition to weakening the casing, the blister can interfere with the proper fit of the case in the rocket's motor mount tube.

In the past, AeroTech has implemented the use of forward seal disks with its longest 29mm, 38mm and 75mm RMS motors. The seal disk is a narrow aluminum ring that seals to the inside of the phenolic liner with a circumferential o-ring. The motor's forward o-ring seals against the forward seal disk when the motor closures are tightened. With the use of the seal disk, the liner o-ring (54mm only) and phenolic or fiber forward insulator are no longer required and will not be included with new reload kits. An added benefit of using the seal disks is that motor cleanup is substantially easier; the disk prevents soot from being deposited on the forward end of the case.

The new 98mm aluminum forward seal disk will be available from AeroTech and its authorized dealers at a price of $20.00 each suggested retail. Three seal disk o-rings will be included with each disk for use with older reloads. Updated assembly drawings and instructions for the affected reloads will soon be available for download in PDF format from the Resource Library on the AeroTech website at https://www.aerotech-rocketry.com.


AeroTech Consumer Aerospace is a division of RCS Rocket Motor Components, Inc., Cedar City, UT.

 

[GaryT]

Gary:
What Size O-Ring is used with the 54mm Seal Disk?

 

[Garoq]

Gary:
What Size O-Ring is used with the 54mm Seal Disk?

#031 (1-7/8" O.D. X 1/16")

 

[GaryT]

Gary Thanks!

But for all the affected 54mm reloads that are out there "now" should we discard the liner o-ring and phenolic or fiber forward insulator and Use the Seal Disk instead?

 

[Garoq]

Gary Thanks!

But for all the affected 54mm reloads that are out there "now" should we discard the liner o-ring and phenolic or fiber forward insulator and Use the Seal Disk instead?

It's up to the customer....the new requirement applies to "current" production. We will however provide o-rings to customers and dealers for retrofitting older reloads upon request.

 

[Donaldsrockets]

I flew an older K695R last month that didn't require a seal disk and it worked just fine but I did notice that a small section of the forward end of the liner appeared to be pushed in a bit but it didn't harm the casing.

Made for a really awesome flight in my Art Applewhite 54mm Stealth oddroc.

I'd say these disks will bring piece of mind and I'll be getting one.

 

[GaryT]

I've used like 4 of those reloads in my 1706 case with no ill effects but I'm definitely getting the disc as well, I assume though if you have the Disc and! an Old Load you DONT use the forward Insulator disc and or the O-ring correct?

 

[Garoq]

I've used like 4 of those reloads in my 1706 case with no ill effects but I'm definitely getting the disc as well, I assume though if you have the Disc and! an Old Load you DONT use the forward Insulator disc and or the O-ring correct?

Right, you don't use the forward insulator and the liner o-ring.

 

[Balsa Bob]

Can we safely assume the Rouse-Tech disks are fully compatible?

 

[Garoq]

Can we safely assume the Rouse-Tech disks are fully compatible?

Yes.

 

[uncle_vanya]

Are the correct o-rings for the seal disk going to be available at NSL? I have arranged for a forward seal disk for my K695R launch - but it's an older reload (6 months?) and does not have the right o-ring for this.

If I fly it without the seal disk using the old method - is Aerotech going to replace my case if something happens?

 

[Garoq]

Are the correct o-rings for the seal disk going to be available at NSL? I have arranged for a forward seal disk for my K695R launch - but it's an older reload (6 months?) and does not have the right o-ring for this.

If I fly it without the seal disk using the old method - is Aerotech going to replace my case if something happens?

I don't know for sure if the dealers will have them there. Email Mark Hayes at [email protected] and we'll send some to you.

 

[WillMarchant]

Are the correct o-rings for the seal disk going to be available at NSL? I have arranged for a forward seal disk for my K695R launch - but it's an older reload (6 months?) and does not have the right o-ring for this.

Ken Allen of Performance hobbies will have a 54mm seal disk and three o-rings supplied courtesy of Aerotech. Well, and courtesy of me too, I suppose!

 

[GaryT]

The Correct size O-Ring needed for the 54mm Seal Disk is
#031 (1-7/8" O.D. X 1/16") And thats Per Aerotech, I found them at my Local Harware Store for .42 each, They only had 4 so I Grabbed'em