# A hoverboard breakthough **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [November 19, 2016, 10:45pm UTC](https://boards.straightdope.com/t/a-hoverboard-breakthough/772485 "2016-11-19T22:45:42Z")\ **Posts on this page:** 10\ **Page:** 2
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [November 22, 2016, 12:40am UTC](https://boards.straightdope.com/t/a-hoverboard-breakthough/772485/21 "2016-11-22T00:40:16Z")
> [@Dr.Strangelove](#): > > Technically, it doesn’t _have_ to be wrong. I suppose. But something pretty close to magic is happening if an engine is producing over 50 hp per pound of its weight (4+ pound engine, 250 hp). ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [November 22, 2016, 12:56am UTC](https://boards.straightdope.com/t/a-hoverboard-breakthough/772485/22 "2016-11-22T00:56:33Z")
> [@Dr.Strangelove](#): > > Technically, it doesn’t _have_ to be wrong. Power is dependent on the exit velocity. 250 hp is 186 kW. 60 lbs is 267 newtons. Divide and you get 700 m/s. That’s mach 2, which is almost certainly higher than the real exit velocity, but it’s not unimaginable. do you know how incredibly loud a jet engine’s exhaust is when it’s supersonic? And do you know you pretty much need reheat (afterburning) just to get \>Mach 1.0 exhaust flow? yes, 1,000 horsepower out of four grapefruit sized engines is “unimaginable.” I mean, [here’s](http://en.konnerhelicopters.com/konnerk1/turbina-tk250/) a helicopter company magnifying how they got 250 horsepower (and as a turboshaft it’s real horsepower, instead of trying to extrapolate thrust\>horsepower) out of 50 kg. 110 lb. engine to get 250 hp. don’t be so eager to believe something just because it’s being pushed by The Verge and Gizmodo. ---
**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\ **Post date:** [November 22, 2016, 1:40am UTC](https://boards.straightdope.com/t/a-hoverboard-breakthough/772485/23 "2016-11-22T01:40:54Z")
> [@dtilque](#): > > From what news I can gather on the Infobahn, a company called Implant Sciences bought the makers of Flyboard Air. Implant Sciences is a privately held defence contractor. They’ve declared Chapter 11 bankruptcy and (some of?) their other assets have been bought by another company called L-3. So it’s hard to say exactly what the status of the Flyboard is, but my spidey-sense is tingling… (well, OK, maybe it’s just gas…) The government already developed this back in the 50s (though larger and bulkier), with a few alternatives proposed through the years. For military use, it would only really be of value if it was quiet, and jet engines are rarely that. > **[Hiller VZ-1 Pawnee](https://en.wikipedia.org/wiki/Hiller_VZ-1_Pawnee)** > > The Hiller VZ-1 Pawnee (U.S. Army designation; earlier Army designation: HO-1) was a unique direct-lift rotor aircraft, using contra-rotating ducted fans for lift inside a platform upon which the single pilot shifted body weight for directional control. The platform was developed starting in 1953 under an Office of Naval Research (ONR) contract to Hiller Aircraft, and flew successfully beginning in 1955. > The original concept had been developed by Charles H. Zimmerman in the late 1940s. Further d... > **[Williams X-Jet](https://en.wikipedia.org/wiki/Williams_X-Jet)** > > The Williams X-Jet, created by Williams International, was a small, single-person, light-weight, Vertical Take Off and Landing (VTOL) aircraft powered by a modified Williams F107 turbofan aircraft engine — designated WR-19-7 — after some minor modifications. The vehicle was nicknamed "The Flying Pulpit" for its shape. It was designed to carry one operator and to be controlled by leaning in the direction of desired travel and by modulating engine output power. It could move in any direction, acce... > **[de Lackner HZ-1 Aerocycle](https://en.wikipedia.org/wiki/De_Lackner_HZ-1_Aerocycle)** > > The HZ-1 Aerocycle, also known as the YHO-2 and by the manufacturer's designation DH-5 Aerocycle, was an American one-man "personal helicopter" developed by de Lackner Helicopters in the mid-1950s. Intended to be operated by inexperienced pilots with a minimum of 20 minutes of instruction, the HZ-1 was expected to become a standard reconnaissance machine with the United States Army. Although early testing showed that the craft had promise for providing mobility on the atomic battlefield, more Du... I’m sure that they’ll test out the Flyboard Air, to see if it does better than the Granddaddies did, but probably you would need a more efficient source of energy than kerosene, to get the device small and light enough, to allow the extra weight needed for sound reduction, weaponry, and supples. So far as I’m aware, jet fuel is still pretty much as good as it gets. ---
**Author:** ![G0sp3l](https://avatars.discourse-cdn.com/v4/letter/g/c68b51/32.png) [@G0sp3l](https://boards.straightdope.com/u/G0sp3l)\ **Post date:** [November 22, 2016, 2:37am UTC](https://boards.straightdope.com/t/a-hoverboard-breakthough/772485/24 "2016-11-22T02:37:39Z")
I’ve always known there was something somewhere that I would prostitute myself to own, and now to see that thing… don’t judge me ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [November 22, 2016, 2:38am UTC](https://boards.straightdope.com/t/a-hoverboard-breakthough/772485/25 "2016-11-22T02:38:58Z")
> [@Xema](#): > > But something pretty close to magic is happening if an engine is producing over 50 hp per pound of its weight (4+ pound engine, 250 hp). Agreed–assuming a 4 lb mass. There are larger RC jet engines than the ones **jz78817** mentions. For instance, [here’s one](http://www.amtjets.com/pdf/Nike_specification.pdf) with 784 N (176 lb) thrust. At a reasonable 250 m/s exit velocity, that’s 262 horsepower. Total engine weight is 25 lbs, so we’re talking only 10:1 PWR here (high, but not crazy high). ---
**Author:** ![cmkeller](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmkeller/32/118_2.png) [@cmkeller](https://boards.straightdope.com/u/cmkeller)\ **Post date:** [November 22, 2016, 2:46am UTC](https://boards.straightdope.com/t/a-hoverboard-breakthough/772485/26 "2016-11-22T02:46:13Z")
Hmm…flying board, Cubs in World Series… This has to be 2015, right? ---
**Author:** ![Son\_of\_a\_Rich](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/son_of_a_rich/32/5439_2.png) [@Son\_of\_a\_Rich](https://boards.straightdope.com/u/Son_of_a_Rich)\ **Post date:** [November 22, 2016, 1:41pm UTC](https://boards.straightdope.com/t/a-hoverboard-breakthough/772485/27 "2016-11-22T13:41:29Z")
Not to harsh anyone’s buzz, but as always with wingless flying machines, there is a death zone between the ground, and sufficient altitude to deploy a ballistic parachute. Wish it wasn’t so. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [November 22, 2016, 5:34pm UTC](https://boards.straightdope.com/t/a-hoverboard-breakthough/772485/28 "2016-11-22T17:34:14Z")
> [@Darren\_Garrison](#): > > Nothing too amazing to it. You could strap a rocket engine to anything. The limitation isn’t the rocket, the limitation is the amount of fuel you can carry. You realise this isn’t a rocket though, right? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [November 22, 2016, 5:55pm UTC](https://boards.straightdope.com/t/a-hoverboard-breakthough/772485/29 "2016-11-22T17:55:41Z")
What seems odd to me about the footage (not that I’m claiming fake) is that the water surface only seems to be perturbed when the device is hovering stationary - I can’t quite work out why this effect disappears almost completely when the pilot leans it over just a little bit. Most of the thrust must still be downwards. ---
**Author:** ![HMS\_Irruncible](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hms_irruncible/32/7394_2.png) [@HMS\_Irruncible](https://boards.straightdope.com/u/HMS_Irruncible)\ **Post date:** [November 22, 2016, 5:58pm UTC](https://boards.straightdope.com/t/a-hoverboard-breakthough/772485/30 "2016-11-22T17:58:40Z")
All fun and games until you lose your balance and some soft fleshy body part gets sucked into the jet intake. [Previous page](https://boards.straightdope.com/t/a-hoverboard-breakthough/772485.md?page=1)