I would not read too much into burn time measured by barometer, especially 0.3
seconds off, and especially particularly fast or slow burns. Barometers on my
long burns have been off by over five seconds, easily verified visually.
- iPhone mail
On Sep 3, 2016, at 2:26 PM, kevinkal@xxxxxxxxxxx wrote:
This was my first J800T. The motor performed excellent, though there are a
couple of minor anomalies that I noticed...
When I went to build it, I noticed that the instructions showed that it used
a Medusa Nozzel, but my J800T-L RMS kit had a single large nozzle. I then
looked up the AeroTech assembly drawing for the J800T and it also showed the
Medusa Nozzel. I was concerned that I didn't have the correct nozzle in my
RMS kit.
Finally, after some google searches, I found some comments on TRF that this
load started shipping with a single large nozzle. All went well with the
flight on the larger nozzle.
I'm not certain how the thrust curve would be affected, but juding from the
motor burn in my video, it burned 0.3 seconds longer than the thrust curves
published for the J800T. The spec sheet says 1.6 seconds burn, but I
measured 1.9 seconds. Thus the average thrust was lower than 800 N. The
total impulse was still around 1280 N-sec. 1280/1.6 = 800N, but from my
flight, 1280/1.9 = 675N Average Thrust. I think this motor might push my
bird over 5K on a day with no winds. For my rocket, I think it's the best
performing 54/1280 RMS reload.
-----Original Message-----
From: Douglas Valkenaar <douglas@xxxxxxxxxxxxx>
To: tccrockets <tccrockets@xxxxxxxxxxxxx>
Sent: Sat, Sep 3, 2016 12:22 pm
Subject: [tccrockets] Re: J800T launch video
I'll be trying one of those at October Skies! First dual-deploy. 😬
On Sat, Sep 3, 2016 at 10:38 AM James Dougherty <jafrado@xxxxxxxxx> wrote:
Nice flight Kevin!!!
Sent from my iPhone
On Sep 2, 2016, at 11:11 PM, kevinkal@xxxxxxxxxxx wrote:
I tossed together ground video, in-flight video and a few stills taken at
the August 20th TCC launch in Helm for my Madcow Level2 Rocket on a J800T.
Love the separated violet/blue flame on this motor.
Here's a link:
https://www.youtube.com/watch?v=wNS36r3-BoU
