From 2b890f6cb7df4214e31e43c8a35f9eb4da0b1c61 Mon Sep 17 00:00:00 2001 From: Bdale Garbee Date: Mon, 10 Jul 2017 12:49:42 -0600 Subject: [PATCH] more text --- rockets/airframes/CorporateColors/index.mdwn | 26 +++++++++++++------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/rockets/airframes/CorporateColors/index.mdwn b/rockets/airframes/CorporateColors/index.mdwn index f62ab0f..20e519d 100644 --- a/rockets/airframes/CorporateColors/index.mdwn +++ b/rockets/airframes/CorporateColors/index.mdwn @@ -17,19 +17,23 @@ tip laminations got hot enough for the epoxy to soften allowing the carbon fiber to be ripped off... West System is and will continue to be my go-to epoxy for normal airframe builds, and worked great on a previous project that got to Mach 2.21... but with a glass transition temperature of 129-242 F, -it's just not up to the challenge of staying together above Mach 3! - -So, for this build, the plan was to use essentially the same design, but -switch to one of the Cotronics high-temperature epoxies. Others have talked -about using lesser epoxy for the bulk of the fin build-up laminations and then -just using Cotronics as a top coat, or the thicker version to build up leading -edges, but it seemed to me that using the lower viscosity type for all of the -fin can laminations might be the easiest way to go. After studying the +it's just not up to the challenge of staying together above Mach 3! + +So, for this build, the plan was to use the same design and build techniques, +but switch to one of the Cotronics high-temperature epoxies. Because high +temperature epoxy is seen as expensive, others have talked about using lesser +epoxy for the bulk of the fin build-up laminations and then just using +Cotronics as a top coat, or the thicker version to build up leading +edges. But it seemed to me that using the lower viscosity type and staying +with the same build approach would both be the easiest way to go, and from +a learning perspective the idea of "change only one variable at a time" really +appealed to me. After studying the options, I chose [Duralco 4461](https://www.cotronics.com/vo/cotr/pdf/4461.pdf) which is supposed to be good to 500 F with a suitable post-cure. A pint kit with shipping cost me nearly $130, but I used much less than half the kit building this airframe. So, in the grand scheme of things, it's not that -expensive. +expensive. I just need to make another fin can or two with it before the +shelf life expires! ## Design Details @@ -37,6 +41,10 @@ This is basically a "2 fins and a nose cone" design, using a single 5 foot length of filament would fiberglass airframe, a filament would nose cone with aluminum tip, and plywood fins covered with tip to tip carbon fiber. +Due to the CTI M2245 reload that was used for the first attempt not being +available for a while, the M3464 Loki Blue from Scott Kormeier at +[Loki Research](http://lokiresearch.com) was chosen to power this attempt. + The fins were made using high quality 1/8" Baltic birch plywood cores glued into slots milled in the airframe tube, then 3 layers of 5.8 oz 2x2 twill carbon fiber were laminated "tip to tip" across the airframe through each -- 2.30.2