JATO (Jet Assisted Take Off) is fun. Just look at all the lovely pictures and try and imagine it with a whole lot of noise and smell to boot. <link>.
Normally, this is provided by small, disposable rocket engines which are jettisoned when they've done a short amount of work. The final goal being to get the aircraft off the runway in a shorter distance and time or at a higher takeoff weight than would otherwise be permitted.
Now, can we do this another way? Yes. Lets use some nice big Electric Ducted Fans (EDF), with a nice rechargeable battery pack. Now, batteries have a not so great energy density but that's a problem that is being slowly solved. We only need a few minutes of power, it's workable now and will improve in the future.
So, the traditional route is to attach JATOs, use them for take off and then jettison them, forming a crater in a nearby field/house. "Can we do better?" is the question. "Yes probably" is the answer. How about we make the jato a small autonomous craft? Now we can use it for take off, jettison it whereby it happily quad-copters it's way on a predetermined plane-avoiding route back to the charging station.
There, aviation, improved a bit.-- bs0u0155, Dec 05 2014 JATO http://en.wikipedia.org/wiki/JATO [bs0u0155, Dec 05 2014] EDF http://www.edfenergy.com/ [not_morrison_rm, Dec 06 2014] Robert Goddard http://en.wikipedia...iquid-fueled_flightCrude, yet effective ... [8th of 7, Dec 06 2014] ahem, fixed.-- bs0u0155, Dec 05 2014 Or you could tether the vehicle to the ground, using a cable to supply electricity. And it doesn't actually have to take off as long as it provides the speed.
And then congratulations, you've invented the electric catapult, in common use on air craft carriers.-- MechE, Dec 05 2014 The big plus points of JATO bottles are:
They require no support infrastructure.
They require no maintenance.
They are extremely simple devices.
They are extremely reliable.
They provide a high specific impulse in a relatively small, lightweight form factor.
Electrical systems don't meet any of these requirements.-- 8th of 7, Dec 05 2014 I was not able to find any video of these JATO devices used as personal jet packs.-- bungston, Dec 05 2014 There's a good reason for that.-- normzone, Dec 06 2014 During WWII, the Germans evaluated the idea of a single-use rocket pack to allow troops to "hop" over mined areas, barbed wire, or difficult terrain i.e. marshland.-- 8th of 7, Dec 06 2014 //the Germans evaluated the idea of a single-use rocket pack to allow troops to "hop" over mined areas,//
And concluded that the mines were a faster, cheaper way of launching their troops into the air and have them come down in an uncontrolled manner.-- bs0u0155, Dec 06 2014 Can we go back to Eclectic Duck Farms please?-- not_morrison_rm, Dec 06 2014 Jet assisted hopping is such an attractive idea. There must be insurmountable issues with keeping the jet pointing down. Maybe spinning the fuel reservoir for gyroscopic stabilization...-- bungston, Dec 06 2014 //springy leg stilts
Good idea and a two-for-one thingy. Suspect the entire Iraq/Afghanistan conflict just in order that coalition forces get an edge at the next paralympics.-- not_morrison_rm, Dec 06 2014 // insurmountable issues with keeping the jet pointing down. //
Not so; vide Robert Goddard's first liquid-fuelled rocket <link>, which placed the venturi above the fuel tank, thus guaranteeing the centre of mass is below the point of suspension.-- 8th of 7, Dec 06 2014 Which would be great - except for the fact it doesn't work.-- lurch, Dec 07 2014 Everyone's a critic ...-- 8th of 7, Dec 07 2014 //venturi above the fuel tank, thus guaranteeing the centre of mass is below the point of suspension//
The supposed advantage of that geometry is a common misconception. Many early rockets had a similar arrangement (nozzles at the top, so that the rocket was "pulled up" from above rather than pushed from below). However, it makes no difference to stability, which is why later rockets always have the nozzles at the bottom, where they can point straight down.-- MaxwellBuchanan, Dec 07 2014 //Many early rockets had a similar arrangement (nozzles at the top,
Surely that was because the test range was Woomera..-- not_morrison_rm, Dec 07 2014 random, halfbakery