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Aeroplane that reaches 80 km altitude !

Posted by: topspeed - Mon Dec 30, 2013 4:45 am
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Aeroplane that reaches 80 km altitude ! 
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Space Walker
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Post Re: Aeroplane that reaches 80 km altitude !   Posted on: Sun Apr 06, 2014 8:52 am
Since it has been pretty silent here...here is my stealth fighter with 25 km ceiling !

:mrgreen:

Powered with 4 x J-85 that was tested by NASA for Mach 3 speeds !

I was thinking of using very lite composite for it to gain possibly 30 km ceiling !


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Post Re: Aeroplane that reaches 80 km altitude !   Posted on: Wed May 21, 2014 2:08 pm
This contain basics for the space craft design; http://people.bath.ac.uk/ensmjc/Notes/stability.pdf

Here is what I am up tp now..a V-8 engined craft to fly at transsonic region.

Feel free to ask. :wink:


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Post Re: Aeroplane that reaches 80 km altitude !   Posted on: Thu Nov 06, 2014 9:00 pm
I am still working on this idea to fly a mother ship to 40-80 km to launch a rocket into space.

Now I have a 100 m spanning ship with 1390 kW from solar panels and a 4 stage rocket that could go Jupiter ( and back ) in a year...and 37 days to Mars and back.

I counted a 1/70 weight compared to APOLLO 11 for instance.

Did you know that the newest high end panels produce 44.7 % efficiency..that is 608 W / m2 at high altitude ?

Paul MacCready's ship SOLAR CHALLENGER flew with 10% efficient panels from London to Paris in 1981.



https://www.youtube.com/watch?v=kAw6RFIVRUo

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Post Re: Aeroplane that reaches 80 km altitude !   Posted on: Thu Dec 11, 2014 7:45 am
Here is the view to it from above !

It is 1/40 of the LZ-129 in volume and 3 x bigger than HK-1 in lifting area.
Supposed to use the Titan II sized rockets booster/nozzles after 50 km altitude and onboard fuel...untill the parasite is released at 80 km altitude in a speed of mach 9 ( that creates the same lift as 70 km/h at sea level ).

Any comments ?

---

Edit: Frontal and rocket added !


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Post Re: Aeroplane that reaches 80 km altitude !   Posted on: Thu Dec 11, 2014 4:25 pm
Just to hold your horses..I remind that solar power alone cannot take even a 8 meter dia prop aeroplane above 40 km.


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Post Re: Aeroplane that reaches 80 km altitude !   Posted on: Fri Dec 12, 2014 12:18 pm
You're quibbling with yourself? :lol:

Also can't go supersonic either (even at altitude which is the real reason for the alt. limit). Propellers become increasingly draggy as you approach the trans sonic boundary.


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Post Re: Aeroplane that reaches 80 km altitude !   Posted on: Fri Dec 12, 2014 9:15 pm
JamesG wrote:
You're quibbling with yourself? :lol:

Also can't go supersonic either (even at altitude which is the real reason for the alt. limit). Propellers become increasingly draggy as you approach the trans sonic boundary.


Yes James G you're maybe right !

I am just trying to figure out how come two people were able brake the speed of sound in 40 km...in free fall ?!

There has never been an aircraft with 8 m dia propellers to fly in 40 km so how can you be sure it becomes too draggy ?

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Post Re: Aeroplane that reaches 80 km altitude !   Posted on: Fri Dec 12, 2014 9:42 pm
The speed of sound is product of the medium, pressure, and temperature (minor)that it travels thru. It is much slower thru lower pressure, thus it is possible for a falling human body (or anything else) to be "supersonic" even though they are only going a few hundred KPH (because air resistance is lower at altitude too). Not the thousand plus KPH at sea level.

http://www.wisegeek.org/what-is-the-speed-of-sound.htm

If your big props turn at a leisurely pace, and assuming they provide enough thrust, there is no reason why they couldn't take you to 40km MSL. The problem is that because of both the reduced lift and sound barrier (caused by reduced pressure). Generally this is overcome by going faster (SR-71) or having a great big wing (U2). But for propellers to provide enough thrust at altitude, its very easy for them to go supersonic which robs energy and can even be damaging (vibration in the props and structure). You have to thread the needle with the maths.


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Post Re: Aeroplane that reaches 80 km altitude !   Posted on: Sat Dec 13, 2014 6:58 am
Quite right James G..math has to be proven for this...any John Nash there to make it work ?

We know that the air pressure has to be really low at high since the density is ridiculously low...as is the temperature.

Density is just 3/1000th that is on the sea level.

So what I am claiming that a large propeller in a super lite large vessel using solar energy and some battery power can due to lower drag of the Mach barrier brake the speed of sound with just a minimal drag disadvantage at 40 000 meters.

:wink:


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Post Re: Aeroplane that reaches 80 km altitude !   Posted on: Sat Dec 13, 2014 10:05 am
For the 8 m dia propeller to turn 290 m/s near the speed of sound takes just 764 rpms.

Amazing ?

:roll:

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Last edited by topspeed on Sat Dec 13, 2014 5:49 pm, edited 1 time in total.



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Post Re: Aeroplane that reaches 80 km altitude !   Posted on: Sat Dec 13, 2014 5:36 pm
topspeed wrote:
For the 8 m dia propeller to turn 290 m/2 near the speed of sound takes just 764 rpms.

Amazing ?

:roll:


And to add to JamesG's comment about possible damage caused to a propeller have a look at cavitation damage on boat propellers easily searchable IIRC its caused by a similar process when the spinning passes the local speed of sound. Though water is a more dense fluid than air I think the maths of fluid dynamics is also similar for gases even though technically fluids and gases have some differences.

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Post Re: Aeroplane that reaches 80 km altitude !   Posted on: Sat Dec 13, 2014 5:50 pm
SANEAlex wrote:
topspeed wrote:
For the 8 m dia propeller to turn 290 m/2 near the speed of sound takes just 764 rpms.

Amazing ?

:roll:


And to add to JamesG's comment about possible damage caused to a propeller have a look at cavitation damage on boat propellers easily searchable IIRC its caused by a similar process when the spinning passes the local speed of sound. Though water is a more dense fluid than air I think the maths of fluid dynamics is also similar for gases even though technically fluids and gases have some differences.


Honestly at 40 km the air is 3/1000th dense the sonic boom will be just a mild puff. SS1 experienced Mach 3.06 at 65 km and it hardly even warms up at temperature.

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Post Re: Aeroplane that reaches 80 km altitude !   Posted on: Sat Dec 13, 2014 6:04 pm
topspeed wrote:
SANEAlex wrote:
topspeed wrote:
For the 8 m dia propeller to turn 290 m/2 near the speed of sound takes just 764 rpms.

Amazing ?

:roll:


And to add to JamesG's comment about possible damage caused to a propeller have a look at cavitation damage on boat propellers easily searchable IIRC its caused by a similar process when the spinning passes the local speed of sound. Though water is a more dense fluid than air I think the maths of fluid dynamics is also similar for gases even though technically fluids and gases have some differences.


Honestly at 40 km the air is 3/1000th dense the sonic boom will be just a mild puff. SS1 experienced Mach 3.06 at 65 km and it hardly even warms up at temperature.


You might be right if you keep speed down to low mach speeds but if you want to get high and fast look at the trouble they had to go to with the X-15 and its pink incarnation

https://www.youtube.com/watch?v=n-dtqDi ... e=youtu.be

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Post Re: Aeroplane that reaches 80 km altitude !   Posted on: Sat Dec 13, 2014 6:35 pm
SANEAlex wrote:

You might be right if you keep speed down to low mach speeds but if you want to get high and fast look at the trouble they had to go to with the X-15 and its pink incarnation

https://www.youtube.com/watch?v=n-dtqDi ... e=youtu.be


Yes Alex I am familiar with the pink X-15. I love the Rushworths 97th run in the program...Mach 6.06 somewhere close to 30 km with standard set up..he flew well.

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Post Re: Aeroplane that reaches 80 km altitude !   Posted on: Mon Dec 15, 2014 3:13 pm
What I do not understand is how exactly will the solar plane stage meaningfully help getting anything in orbit.

Orbit is a function of velocity, not height. You need some 28 thousand km/h of delta-v to get to LEO.

How much of that delta-v does the solar plane contributes to? 1 thousand km/h? Maybe less?

It seems the whole concept is "launch from great altitude, avoid atmospheric drag". However, that atmospheric drag is a very small part of the consumption of a rocket. Most of it goes to achieve the 28 thousand km/h. And ANYWAY, after less than 1 minute of acceleration a ground-launched rocket is already taller than the Solar Plane might go... and much faster already.

Therefore, it´s a LOT of added complexity (an extra stage that is a GIGANTIC solar plane which contributes almost nothing to delta-v) with not much benefit.


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