[AR] Re: Space shot and it flight profile.
- From: Ben Brockert <wikkit@xxxxxxxxx>
- To: "arocket@xxxxxxxxxxxxx" <arocket@xxxxxxxxxxxxx>
- Date: Sat, 16 Nov 2013 02:23:38 -0700
There's definitely a drag loss vs gravity loss trade off.
I forget, were you gimbaling or steering with fins, or what?
Ben
On Saturday, November 16, 2013, wrote:
> The reason I asked was that the software we first used with the Condor
> Project spit out a solution to our problem of not building a tank to get to
> 16+ km, which was the goal, was to throttleable back the motor. As a bonus,
> it actually gave us a little bit more altitude than going full bore. in the
> sim, We ran full throttle at 450 lbf for 9 seconds and then went down to
> 110lbf for the next 60 seconds or so. The sim shows us hitting mach .92 at
> throttle back and then slowing down to about mach .83 before gaining speed
> again and going through mach a about 11Km. The rocket using this flight
> profile was 26% lighter and got 10 to 15% higher than a sim of the same
> design but full throttle until burn out.
>
> I understand the problem with solids but there has got to be a way to keep
> it under mach in the initial boost stage so that going through mach and
> heating is just not an issue anymore.
>
> Robert
>
> At 06:22 PM 11/15/2013, you wrote:
>
>> On Fri, Nov 15, 2013 at 4:19 PM, <qbert@xxxxxxxxxxxxxxx> wrote:
>> > After going through several space blog updates I ran into a Sugar Shot
>> to
>> > Space blog which then led me to Bens Brokets assessment of heat vs
>> speed and
>> > altitude. The question I have, would it not be better to go slower
>> though
>> > the lower atmosphere, say up to 40,000, or even 60,000 feet until
>> > approaching mach lessening both the dynamic forces and heating.
>> >
>> > Robert
>>
>>
>> If the thought "would it not be better to go slower though the lower
>> atmosphere" is run as far as possible, the usual conclusion is "let's
>> build a rockoon" or "let's build a space elevator". But going
>> hypersonic at 13km isn't impossible, it just takes some attention to
>> materials and design.
>>
>> Ben
>>
>
>
>
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