From aeb73f6316774d399edd8f5520efedce381f5eeb Mon Sep 17 00:00:00 2001 From: Bdale Garbee Date: Mon, 22 Oct 2018 16:54:11 -0600 Subject: [PATCH] more hacking on the text --- rockets/airframes/MehGaNuke/index.mdwn | 51 +++++++++++++++++++------- 1 file changed, 38 insertions(+), 13 deletions(-) diff --git a/rockets/airframes/MehGaNuke/index.mdwn b/rockets/airframes/MehGaNuke/index.mdwn index 1d80528..1d067a1 100644 --- a/rockets/airframes/MehGaNuke/index.mdwn +++ b/rockets/airframes/MehGaNuke/index.mdwn @@ -163,17 +163,42 @@ The first flight of this airframe was at the [Kloudbusters](http://kloudbusters.org/) [Airfest 24](http://kloudbusters.org/airfest/) in Argonia, Kansas, USA, on Saturday, 1 September 2018. The motor was a 6-inch "O" built by James -Russell using his well-known "Russell Red" formula. Due to a slightly larger -than optimal nozzle throat, the motor burn was a bit longer and average thrust -a bit lower than expected... but a side-effect was a 9-10 foot brilliant red -flame tail that was awesome to see! The rocket hit about Mach 0.6 on the way -to 8068 feet above ground, and was recovered safely. Weather-cocking due to -wind caused the airframe to have a residual speed at apogee of nearly 60 meters -per second, so not surprisingly there was some modest zippering of the top of -the airframe. It also seems clear that the ARRD failed to retain the deployment -bag, as the main chute deployed a few seconds after apogee. The stress at -deployment tore the strap off the deployment bag, and the deployment bag was not -recovered. Some minor re-design of the deployment sequence seems indicated -before future flights. All in all, though, this was an outstanding group -effort, a lovely flight, and a huge crowd-pleaser! +Russell using his well-known "Russell Red" formula. The total launch mass +was about 205 pounds on the rail. Due to a slightly larger than optimal +nozzle throat, the motor burn at 7.7 seconds was a bit longer than expected, +pushing the airframe with an average acceleration of only 2.89 G to a +maximum speed of Mach 0.6 on the way to 8068 feet above ground. + +Weather-cocking due to wind caused the airframe to have a residual speed at +apogee of nearly 60 meters per second, so not surprisingly there was zippering +of the top of the main airframe tube. It also seems clear that the ARRD +failed to retain the deployment bag, as the main chute deployed a few seconds +after apogee. We had some difficulty with the ARRD during assembly on the +rail, so this wasn't terribly surprising. Recovery was completely safe with +the nose descending under 2 5-foot mil-surplus chutes, and the bulk of the +airframe descending under a 28-foot mil-surplus chute. + +[Tender Descender](http://www.tinderrocketry.com/l13-tender-descender-tether). + +The stress at deployment tore the strap off the deployment bag, and the +deployment bag was not recovered. After studying the zipper and thinking +about the main deployment sequence, several changes will be made before the +next flight: + + - The main airframe tube will be replaced with a tube that's a bit + longer (for greater stability), and has an internal 7.5-8" diameter + tube instead of the flat baffle to ease main chute deployment. + + - Switch from the ARRD to the largest [Tender Descender](http://www.tinderrocketry.com/l13-tender-descender-tether) for main deployment + + - Add a TeleGPS to the nose assembly so it can be tracked + independently, and let it come down under the 2 existing 5-foot + chutes. Add a third 5-foot chute to be a dedicated pilot for the + 28-foot main chute. + +These changes should reduce the chance of another zipper, and reduce the amount +of strap we need to stuff into the bay. + +All in all, this first flight was an outstanding group effort, a lovely +flight, and a huge crowd-pleaser! -- 2.30.2