Would need info on what the solid fuel contains
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that… I don’t know. gotta do more research
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Thats very cool, burn time several minutes is awesome
Specific impulse is ISP. From my knowledge, Specific impulse has always been defined either as ISP, or as Ve in a looser definition, never as DeltaV.
For reference, the images talks about multiple systems - meteor, HSAD, T3, making it even more unlikely to be referring to DeltaV
Note these powerpoints and brochures arent usually made by an engineer…
The values and units both make sense for it to be referring to deltaV, which is a metric of impulse.
something else that indicates the meteor can burn for a few minutes is that the motor casing is made to resist the equivalent of ~mach 3.5 - 3.7 (500°C+) heat for “a few minutes”
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A DeltaV of 10000m/s would not make sense either. Thats intercontinental ballistic missiles values of DeltaV. Although the missile is fully atmospheric and not ballistic, this value is just way too high for a missile with a range within 500km. There’s not that much drag that it would have 10000m/s of DeltaV to achieve its range
I disagree, i am expecting ramjet to have quite a lot of drag, given its needed for the ducts/intakes to function, it also does not have variable inlet ramps.
That is deltaV specific to the motor, not the missile, with the entire missiles weight included… it will be much lower…
If we include a 40kg booster, a 190kg missile would have 2500m/s deltaV provided by the ramjet. Giving roughly 3000m/s total for the combined booster and ramjet.
But isn’t around 1,000 s of ISP about what you would expect from a TDR ramjet? What makes you think it’s delta-v?
Perhaps, but i would have expected a boron loaded ramjet to have a slightly higher ISP than 1000s, deltaV seems to work well within that range using speculative values.
What I can find is that the ASMP nuclear missile from France, which uses boron enriched fuel, has an ISP of around 600-800s at a maximum (obviously no concrete source tho). For reference, when the French gov tested normal solid fuel they achieved around 300s
Also, if I where to take your hypothesis of it being a DeltaV, with a typical 3:1 ratio of propellant to structure of the motor, then I’d stil get an ISP of around 1000, so Ve of 10000.
Edit : I’ve actually been surprised looking into them just now how inefficient they are. They actually gain their efficiency through the fact that they don’t carry the oxidizer, not through the efficiency of the engine itself
This is using liquid fuel, which we found out to be more efficient as I shown in the research I showed above
Assume thats 1:3, which is probably broadly accurate because the ramjets we are looking at for meteor require a booster.
boron enriched fuel? i thought the asmp used kerosene, since it’s a liquid fuel ramjet
It is liquid. From what I’ve seen it also looks like it’s also boron enriched ?
I do have literally 10 minutes of research experience on the subject, so obviously take it with a rock of salt.
Maybe it’s just the latest variant ASMP-A as well. I’ll need to check to more carefully
Its not the same Isp, you’re comparing apples to oranges.
This is an Isp defined in m/s (specific impulse)
This is an Isp defined in seconds (normalized specific impulse)
If I’m understanding it correctly, the conversion from the specific impulse to the normalized specific impulse would be
Isp(s) = (7000 - 10000m/s)/9.80665(m/s^2)
Isp(s) = ~713.8 - 1019.7s
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Solid fuels should be more energy dense/mass efficient?
That’s my current belief as well. The Specific Impulse (m/s) is actually a loose definition and is actually the gas exhaust Ve, as defined : ISP = Ve/because