Author Archives: johnhare

johnhare

About johnhare

I do construction for a living and aerospace as an occasional hobby. I am an inventor and a bit of an entrepreneur. I've been self employed since the 1980s and working in concrete since the 1970s. When I grow up, I want to work with rockets and spacecraft. I did a stupid rocket trick a few decades back and decided not to try another hot fire without adult supervision. Haven't located much of that as we are all big kids when working with our passions.

Reverse Rocket

This is a post about an idea by Doug Plata. His idea is to put multiple propellant tanks on top with just enough structure to keep them intact and drop them in pairs as they drain. Under the tanks is … Continue reading

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Getting My Numbers

This is an explanation of how I get BOTE numbers for such things as the comparison between LH2 and CH4 propellants as in Jons’ last post. The focus Jon had was how much H2 do you need to carry to … Continue reading

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Semi-Staged Combustion

It is interesting comparing the two best known first stages in the US that use kerosene and LOX. The Atlas 5 and the Falcon 9 use a similar fuel in their first stages and then diverge in the technical aspects. … Continue reading

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Electric Inducer Pump

It takes pressure in the tank to suppress cavitation in the pumps for rocket engines. It is customary to use helium for most pressurization due to its’ low molecular weight. Unfortunately, it can take a lot of helium in some … Continue reading

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Notchbell Nozzle

Several years back I suggested a type of compensating nozzle that should be inexpensive to build and test. Unfortunately the ones I made for demonstration with compressed air were hit and miss as I didn’t have the theory quite right. … Continue reading

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Old Engines

Some before, and many after the accident criticized the use of old engines for the Antares. Many references were made to the long storage time with some mention of them as antiques. The refurbishment of these engines didn’t seem to … Continue reading

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Sea Launch Sold

I read just yesterday that Sea Launch has been sold. Then I get an email last night that this post from August 2014 inspired the purchase that solidified when SpaceX was able to recover on land the first try after … Continue reading

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Max Diameter Compensating Nozzle

One of the items that seems to be missing from the current crop of LVs is any hint of compensating Nozzles. So a nozzle normally flies that is over expanded at sea level, optimum for a few seconds at some … Continue reading

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Seven Core RLB

In the discussion on Jons’ last post it was mentioned that seven cores could be used in the VTVL booster technique with the outer six semi-permanently attached as a single unit. If they are close to gas-n-go on landing, then … Continue reading

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Long Range Stage Recovery

Recovering stages from far down range is likely to be on the agenda for several companies in the next decade or so. RTLS for the boosters or a first stage is a different proposition than collecting something from Mach several … Continue reading

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