Simon
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| posted on 1/1/06 at 12:53 AM |
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Mythbusters Jet Pack
Anyone watch this - I've seen it twice and think they could've tried harder.
Anyone know how to calculate the amount of air moved to provide thrust/lift - I understand the principle of prop pitch, but want to know volumes etc.
May make a model of the Solotrek.
ATB
Simon
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steve_gus
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| posted on 1/1/06 at 01:07 AM |
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Havnt seen the program - was it air only, or combustion like a rocket motor?
I have seen a movie called October Sky (and read the book called Rocket boys). Its about a bunch of kids in the late fifties (one of whom goes on to
work for NASA) and their exploits in making rockets.
There are some complex calculations in determining rocket thrust. (Guess thats why rocket science is held up to be dififcult  ) The shape and
geomety of the nozzle from the engine is VITAL to get the maximum thrust from the motor....... dunno if this is the same for compressed or blown
air.
atb
steve
[Edited on 1/1/06 by steve_gus]
http://www.locostbuilder.co.uk
Just knock off the 's'!
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Simon
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| posted on 1/1/06 at 01:24 AM |
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Steve,
It's air - two fans above head, left and right, powered by petrol engine (central prop and belt drive to fans)
Like this:
http://www.solotrek.com/devhistory.html
just on a smaller budget - they had $2000 and bought plans off the internet
"Build Yourself a Deathtrap for as alittle as etc etc etc"
ATB
Simon
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JoelP
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| posted on 1/1/06 at 02:05 AM |
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i saw the 3000bhp rocket car experiment, which was fun
Beware! Bourettes is binfectious.
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paulf
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| posted on 1/1/06 at 12:00 PM |
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I saw that and was also a bit dissapointed with how they did it.
The belt drive looked a bit slack and I suspect a lot of power was lost in it slipping, I would have used toothed belts if i was going to attempt it
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The engine must have made anple power if it was correctly transmitted.
Paul.
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Simon
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| posted on 1/1/06 at 07:50 PM |
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Paul, I think smooth belts are ok - I believe they are used in the Robinson R22. I suspect that they needed reduced gearing on the fans to speed them
up, maybe even increase pitch/diameter.
ATB
Simon
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paulf
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| posted on 1/1/06 at 08:33 PM |
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I think your correct about the robinson helicopter but i remeber it as having a multiple belt set up and also a rigid framework to allow correct
tensioning.There device was to flimsy to allow the belts to be kept under tension plus as you say the pulley dias were to small to allow them to
transmit the power.It was a pity as i think it could really be possible to make a working unit , however my wife wont let me
quote:
Originally posted by Simon
Paul, I think smooth belts are ok - I believe they are used in the Robinson R22. I suspect that they needed reduced gearing on the fans to speed them
up, maybe even increase pitch/diameter.
ATB
Simon
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Cita
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| posted on 1/1/06 at 11:57 PM |
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The Solotrek was a big joke!!!!
A lot of tax money wasted for a wrong concept.
To "calculate" thrust,you need to transport a mass of air greater than your take-off weigth every second.In other words if your craft
fully loaded weighs 500 lbs than your rotor(s) must be able to transport 500 lbs of air every second,from above the rotordisc to below the
rotordisc.
If you understand pitch of a rotor or wing than this is easy.
It's obvious that rotor RPM plays a major role in this.
Cheers Cita
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Simon
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| posted on 2/1/06 at 12:01 AM |
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Cita,
Solotrek funding was cancelled at the time the most progress was being made - ie right at the time of the first test flights. This was due to
(private) investors setting immoveable time frames to certain progress goals that weren't met.
That was the "joke"
ATB
Simon
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Cita
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| posted on 2/1/06 at 12:09 AM |
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I think the concept was a joke to Simon
Every helicopter has a dead men's curve and that curve for the Solotrek was, to say the least not very attractive.
Being unable to autorotate, the parachute recovery system needs height to fully do it's job.
After spending what....a few million dollars,two feet in the air is not much for all the technology-time and money invested!
No wonder the private investors where a bit worried
Cheers Cita
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Simon
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| posted on 2/1/06 at 12:25 AM |
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Well Paul Moller has spent upwards of $200m and he's managed the same.
I suppose you're of the thinking that perhaps Henry Ford shouldn't have been lent a few hundred bucks so he could start a car production
facility or Frank Whittle should have kept his dream in his head.
Simon
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Cita
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| posted on 2/1/06 at 10:36 AM |
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It's not because P. Moller has spend more than 200 million$ of other people's money on a never ending story that it justify the Solotrek
concept.
If you compare Sir Frank Whittle's work with the Solotrek than it's obvious that you have no clue about the value of rotorcraft like the
Solotrek!
The Solotrek cannot autorotate so either you fly it slowly very close to the ground,a few feet at the max,or fly it way up high so that the recovery
system can bring you safely back to earth.
The question is what about the period when you try to reach that safe altitude and you have an engine failure?
I'm all in favour of supporting new idea's especially in the aircraft scenery Simon but some things are simply not worth the attention and
the money inspite of the sometimes immaculate hype that's builded around some projects.
A long time ago I posted a picture of an Austrian guy who builded himself a small co-axial helicopter.He has been flying this thing many times at
altitudes and speeds never achieved by the Solotrek yet, he spended less money than the Solotrek staff has spended on coffee!!!
If you see with what means this guy has builded his little flying machine than it makes me angry Simon that millions of (often) taxpayers money are
spend on projects that are deemed to fail simply due to concept mistakes,which everyone can spot.
Believe me,the Solotrek is one of them and I'm sure that several people on this forum could build a similar craft like the Solotrek for far less
money and probably outperform the Solotrek.
Cheers Cita
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