Supersonic Flight and Sonic Booms

Discussions on high/extreme altitude and mach busting rockets.

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SpaceManMat
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Re: Supersonic Flight and Sonic Booms

Postby SpaceManMat » Thu May 05, 2016 5:46 pm

Yikes, Mach 3 in the stasophere is about 370C.
QRS: 124
AMRS: 32 L2 RSO
Highest Altitude: 13,647 feet
Fastest Flight: Mach 1.55
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Re: Supersonic Flight and Sonic Booms

Postby jase » Thu May 05, 2016 6:21 pm

OTT - modified kettle, 'lets get this coffee brewed quicker, first class are waiting!'

Mat - yup, reason why flights between Mach 2 and Mach 3 are 'exponential' more difficult?

Posted these today as a place holder (for me) and as an interesting point (for others)...

Without going into detail, I ran a sim today on a previous flight Noel and I did but with a different motor (M650 sub-minimum diameter to 30k feet), with new motor sim said Mach 4.49 so I needed to do some 'goggling', remembered this thread, tried some single malt(s)(maybe plural), and posted what I found...(note to self - it'll need a 'sanity check' before even considering to attempt it)...

The Concorde image I thought was very cool, and relevant for us :!:
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Re: Supersonic Flight and Sonic Booms

Postby SpaceManMat » Thu May 05, 2016 7:01 pm

Some of the guys on TRF had discussions about N5800 and Mach 4+ flights that failed of course. Not sure thats survivable without large amounts of metal, wonder what Nic thinks the limit of his leading edge construction technique is?

Mach 4.5 on the graph is about 870C. What's the plan?
QRS: 124
AMRS: 32 L2 RSO
Highest Altitude: 13,647 feet
Fastest Flight: Mach 1.55
Largest Motor: CTI 1115J530 IM
Current Project: X Wing

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Re: Supersonic Flight and Sonic Booms

Postby jase » Thu May 05, 2016 9:09 pm

I can hold a Bic lighter against your arm at nearly 2,000C for a moment :wink: and you can survive :shock:

imagine Nic's ingenious design at half the thickness (fins) and half the weight...

Defence materiel :lol: 8)
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Re: Supersonic Flight and Sonic Booms

Postby Lister » Thu May 05, 2016 10:03 pm

When did you get more unobtanium.. You been holding out on me?

I'm bringing a hard hat to that launch :shock:

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Re: Supersonic Flight and Sonic Booms

Postby High Impulse » Thu May 05, 2016 10:34 pm

I know somewhere with an abundant supply of Ti6Al4V which would probably do the job...

Although the DMTC probably wouldn't be very impressed if it were strapped to an N5800 :(
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Re: Supersonic Flight and Sonic Booms

Postby vance2loud » Fri May 06, 2016 1:55 am

High Impulse wrote:I know somewhere with an abundant supply of Ti6Al4V which would probably do the job...

Although the DMTC probably wouldn't be very impressed if it were strapped to an N5800 :(


Just doing a bit of quality control :lol:
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Re: Supersonic Flight and Sonic Booms

Postby kopius » Fri May 06, 2016 6:57 am

SpaceManMat wrote:Some of the guys on TRF had discussions about N5800 and Mach 4+ flights that failed of course. Not sure thats survivable without large amounts of metal


Most of those flights were never going to survive based on design, irrelevant of materials used. There are a number of attempts that sitting on the pad had incompatible stability margins for the speeds predicted amongst MANY other flaws.

It was actually disappointing to see these flights approved by the TRA class3 committee, however it was either due to a lack of competence or a 'who cares' mentality. It is quite easy to make a simulation go well beyond the capabilities, but to not understand/appreciate/accept what the reality is, is IMO negligent. Remembering how many attempts there have been vs how many successful flights is evidence of this
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Re: Supersonic Flight and Sonic Booms

Postby Scoop1261 » Fri May 06, 2016 8:21 am

kopius wrote:
Most of those flights were never going to survive based on design, irrelevant of materials used. There are a number of attempts that sitting on the pad had incompatible stability margins for the speeds predicted amongst MANY other flaws.

It was actually disappointing to see these flights approved by the TRA class3 committee, however it was either due to a lack of competence or a 'who cares' mentality. It is quite easy to make a simulation go well beyond the capabilities, but to not understand/appreciate/accept what the reality is, is IMO negligent. Remembering how many attempts there have been vs how many successful flights is evidence of this



I'm sure we will have some robust & humorous discussions regarding unsuccessful minimum diameter N5800 flight at Williams in a couple weeks, because we will have all of the leading exponents in taming these challenging motors in attendance!

But yeah....It is disappointing to see flights approved by the TRA Class 3 committee that clearly did not have the basic parameters of stability addressed. I know that my own two stage minimum diameter rocket had some glaring issues that were quite obviously "overlooked" because RASAERO could not simulate a two stage rocket at the time of submission.

I can remember a couple of younger chaps out on the Black Rock Playa who were quite adamant that their rocket shredded because of supersonic waves unseating the nosecone and thereby creating instability......... Meh! .....Amateurs!......... Much to learn about the way of the supersonic have they!
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Re: Supersonic Flight and Sonic Booms

Postby SpaceManMat » Fri May 06, 2016 12:43 pm

Sometimes I think we put far too much emphasis and trial and error as the primary learning tool. It should not be that way IMO, what we are doing is known so we should be doing our homework upfront. Ok I know that I'm probably biased as it suits my build style to do things that way, but if your going to chuck a thousand dollars or more at a bird you should at least do your best to avoid as many of the obvious pitfalls as you can.
QRS: 124
AMRS: 32 L2 RSO
Highest Altitude: 13,647 feet
Fastest Flight: Mach 1.55
Largest Motor: CTI 1115J530 IM
Current Project: X Wing

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Re: Supersonic Flight and Sonic Booms

Postby OverTheTop » Fri May 06, 2016 1:00 pm

OTT - modified kettle, 'lets get this coffee brewed quicker, first class are waiting!'


At the cruise altitude of the Concorde (60k') you would only have to open the cabin to atmosphere and water will boil at around 38degC. No additional heat input required. It would be a bit unpleasant for the customers though (water = humans).
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SpaceManMat
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Re: Supersonic Flight and Sonic Booms

Postby SpaceManMat » Fri May 06, 2016 1:23 pm

OTT - modified kettle, 'lets get this coffee brewed quicker, first class are waiting!'


Great way to cool the plane skin down. Just hope everyone wants to drink a lot of coffee.
QRS: 124
AMRS: 32 L2 RSO
Highest Altitude: 13,647 feet
Fastest Flight: Mach 1.55
Largest Motor: CTI 1115J530 IM
Current Project: X Wing

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Re: Supersonic Flight and Sonic Booms

Postby High Impulse » Fri May 06, 2016 5:51 pm

vance2loud wrote:
High Impulse wrote:I know somewhere with an abundant supply of Ti6Al4V which would probably do the job...

Although the DMTC probably wouldn't be very impressed if it were strapped to an N5800 :(


Just doing a bit of quality control :lol:


Well if quality control was the aim, i know for a fact that there is a Carbon-Carbon filament winder in operation at UQ atm which would pair quite nicely with a Ti fin can...
L1: Callisto - H410VM

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jase
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Re: Supersonic Flight and Sonic Booms

Postby jase » Fri May 06, 2016 7:57 pm

Sheesh! I just wanted to talk about rockets....

I reckon 6061 T6 would do the job - BTW, I don't beleive my drunken sim at all, not even a little bit.

Mach 3 ish I think is doable with a 75mm motor of sufficient savagery.

I'm also entertaining a sub min diameter 6" project - not outside the realms of possibility...

Yeah, it's all piss-and-wind until you step up and do it.

Ti sure, why not! Although I'm not sure any high performance sounding rockets ever utilized it for entire fin? Well, leading edges of this bad boy http://www.isas.jaxa.jp/e/enterp/rocket ... s520.shtml
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