From my experience you will not get accurate altitude simulations from Open
Rocket. Especially with flights in the transonic region. Open rocket is a great
tool for design, weight and balance, CP to CG and general simulation. I have
found that to get accurate altitude simulations for a particular rocket. You
need to have a good idea as to what the actual coefficient of drag is. I have
yet to find an easy way to adjust drag coefficients in open rocket. So I use
RockSim and RAS Aero where you can easily adjust the drag coefficient to match
the real world data.
Here is my process. After building the rocket. Enter all the actual weight and
balance information to match the actual rocket into the simulation. Fly the
rocket at least three times on different motors in the real world gathering
barometric and accelerometer data from multiple flight controllers. Adjust drag
coefficient to match the actual flight data achieved with the motors and
conditions. Then you will get more accurate simulations of the actual rocket.
If you are not building an actual rocket and just living in the virtual world.
Then I would play around with materials and surfaces in open rocket adjusting
the drag to lower your over all coefficient of drag. I would create some
unobtanium’s with really low drag numbers to trick Open Rocket into lower
overall drag coefficients.
I hope this helps,
Whit
From: arocket-bounce@xxxxxxxxxxxxx <arocket-bounce@xxxxxxxxxxxxx> On Behalf Of
Raum
Sent: Wednesday, April 5, 2023 8:00 AM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: 10km (30k feet) with a K300
It goes at mach for 9 seconds, I tried to incorporate the boat tail and changed
the fins a bit. Still got roughly 7500m, any recommendations? Thanks in
advance.[cid:image001.png@01D96799.7ACEA300][cid:image002.png@01D96799.7ACEA300]
On 4 Apr 2023, at 21:20, Ben Brockert
<wikkit@xxxxxxxxx<mailto:wikkit@xxxxxxxxx>> wrote:
It’s a nose cone for supersonic flight, how much of the flight is supersonic? I
don’t have the curves memorized, may be a silly question. If the 509 m/s is top
speed a blunter nose might be better.
Can you fashion some quantity of boat tail? Often the winners of altitude
competitions with a given kit at HPR meets I’ve been to are ones who had
“engine retainer”s whose purpose were perhaps not purely engine retaining.
On Tuesday, April 4, 2023, Raum
<Rocketry101@xxxxxxxxxxx<mailto:Rocketry101@xxxxxxxxxxx>> wrote:
Hi guys,
After testing my motors for a while I am going to try 10km with a k (roughly
1400Ns, 600Ns average thrust). I saw a couple of records on the Tripoli website
with K250 and K300 motors close and above 30k feet. The problem I have is that
I can’t seem to get open rocket show me the magic number. Do you guys see any
improvements I can make (I only wanted to reach the altitude that’s why I
haven’t included the altimeters and parachutes)?<Screenshot 2023-04-04 at
21.07.46.png>