Ebay Ram

[Mark]

http://cgi.ebay.com/Thor-ram-jet-not-ga ... dZViewItem

[Zippiot]

that is a pretty cool design, what is the most common operation speed of that design? i read that most non-moving parts ramjets are capable for 2 mach numbers from when it can be lit, so this thing must have been moving pretty fast just to light from the look of it

[Rossco]

Now is this an odd statement or what!

When this unit launched, by the time the exhaust passed where the intake had been it was already traveling at 1.5 times the speed of sound and dug a 5ft deep crater in the ground behind the launcher.

Rossco

[Zippiot]

so it destroyed its own launcher? i skimmed through the statement and it wasnt written greatly...worded i mean

[Zippiot]

sry scratch that

it just seems weird to me that the ram was started before it left the tube, that much have been one hell of a launcher. any ideas wut powered it? rocket pneumatic hydraulic or mechanical

[Rossco]

It would have to be pnumatic woudnt it? Or some sort of focused explosive? That is of coarse if his idea of operation is accurate!
No mechanical or rocket propulsion could let of that much instant force from static? If so, it would be a hell of a sling shot!

What sort of acceleration would that be? Seems rediculous to me.
I dont know what length the thing is, although he states that it could fit within a coffee table. Now, unless its a table as in a 20' BAR, i say that it would be limited to max 6'. mach1.5 in 6'!!!!!!!!! Surely it would turn itself inside out?
Someone with lotsa numbers crunch that for me please.

This, as you state, could be the only way that it could light, and power itself off the launcher! And then, fair enough, i can see it diggin a reall good hole at the launcher!

Rossco

[Zippiot]

think of a pellet rifle. the barrel (on mine for example) is around 16 inches long, and the pellet in like 6 millimeters long. it goes 1000 fps (like 681 mph) and kicks like a mule. i cant imagine the amount of force required to get this giant to double the speed of my pellet in a barrel miniscruel in comparison...

but maybe we are just missing a big link here...

[Mark]

Thor tidbit.
http://en.wikipedia.org/wiki/Bloodhound_SAM

[Zippiot]

4 solid rocket boosters, each is considerably larger than the thor (but looks like smaller diamter)

that must be 1 big missle, cause from the pic of the thor it looks like quite a large ramjet

[Rossco]

mmm, thanks Mark.

Ha, just idly sitting here critisising without a spot of research!

BUT
By the looks of that, it gets up to Ram speed in a little more distance than he is stating!
The boosters look to be very long for their diameter, this would indiate a fair burn time?
And yep, 4 of them, pushing 2000Kg, i would say could dig a bit of a hole on the launchpad!

Rossco

[Fricke]

Hi -

I have some first hand info on the Bloodhound and Thor ramjet engine...

The missile had two Thor Ramjet. It was also fitted with 4 solid fuel startingrockets, These rockets had the nozzle angeled about 15 degrees to improve stability at launch.They burned for about 4 seconds,and was, together with their fixet stabilisators, dropped. The missile had accelerated from zero to Mach over 1. Then the Thor engine delivered the thrust.The missile had 4 vings to steer it. It could not dive, so it had to roll over 180 degrees to do it. It was guided to the target by the eco from the tracking radar from the ground. It had an radarreiciver in the nose. The warhead was an20 kg high explosive charge, surroundet of two layers of stell rods welded together in zigzac. These steelbars formed an ring of 20 meters before it splitted. It cut the target cross over!
In my actice service in the Swedish Air Force I have seen two launching.In both cases the target ( an Jindivic target radiocontrolled plane) got an direct hit at an altitude of more than 16000 m.

My Father worked with these in the 60ies...

And I can thell that it´s a big beast. There is one on display at the Museum 6 km from me.

//Fredrik

[leo]

I have tried to calculate it, this is my conclusion.(maybe wrong).
If the Thor is reaching sound speed in 4 seconds it has to accelerate with 10 G.
And its has to move more than 700 meters in that time.
I calculate it for going strait up, this probably never happened.

If the Thor would reach 1,5 times the speed off sound in 6 feet it has to accelerate with almost 8000 G in around 0.007 seconds.
This for sure would turn it inside out.
But maths are difficult for me, someone correct me please.

[Zippiot]

we were wrong from the start about the 6 feet thing. the wording on the site sumhow lead us to believe that it was launched from its 6 foot device and reached ramjet start by the end of it. we assumed it was tube launched until a pic of it strapped to a missle was shown. it wont get to mach 1.5 in 6 feet, maybe 6 body lengths (the missle looks huge) that seems doable, but not in 6 feet...

[Fricke]

Leo -

Does a RAMJET really need to achive speeds over Mach 1 to start?
If I remeber correctly (It´s been several years since I looked into Ramjets) there have been some Ramjets that could operate from ~400 km/h...

[Zippiot]

i have 2 ramjets that can start with the air from my shop vac. its all about the design, a ramjet can usually achieve 2 mach numbers from the speed that it is started at (designed to start at). i doubt that the one i made out of an aerosol can will work at mach 2...

there have been ramjets that start to produce thrust as low as 200 mph!!

but the most fuel efficient speed for a ramjet is between mach 2.5 and 2.7