Reinhardt Behm wrote>AT Friday 10 August 2018 14:53, 698839253X6D445TD@nospam.org wrote: > >> Reinhardt Behm wrote >>>No, yet can bet on the direction. ;-) >> >> Hard to tell, I was reading about a case in America I think it was, where >> a screw in the pitch change rod to the rotor mechanism fell out, >> the pitch could not be altered, and the heli kept gaining altitude. >> You cannot reduce motor speed, changes in altitude are controlled by the >> rotor mechanism. One of the passengers had to hang out outside and connect >> something to the control mechanism and only then could they make an >> emergency landing. >> >> That mechanism should be checked before every take off, climb on the >> thing, look if it is still OK. >> Very nice piece of mechanics actually: >> https://en.wikipedia.org/wiki/Helicopter_rotor >> >https://en.wikipedia.org/wiki/Helicopter_rotor#/media/File:Fully_articulated_main_rotor_head.svg >> >> :-) > >Normally you can control engine speed.It seems this one could not, that could be the case for some systems: From: https://en.wikipedia.org/wiki/Helicopter_flight_controls In many piston engine-powered helicopters, the pilot manipulates the throttle to maintain rotor speed. Turbine engine helicopters, and some piston helicopters, use governors or other electro-mechanical control systems to maintain rotor speed and relieve the pilot of routine responsibility for that task. (There is normally also a manual reversion available in the event of a governor failure.)>I had a RC heli with a similar problem. When the connection between >controller and heli was lost it went to full thrust and climbed until the >batteries ran dry. Once it got lost in such a situation. >Using Bluetooth for the connection was just broken by design, going to full >thrust was the other design error.I do not have a RC heli, just a Hubsan quadcopter and an Axion LaserArrow plane. I did a lot of modifications to the electronics. Things are getting a bit restricted foe flying here, most of this part of the country is now forbidden for drones. I am next to a mil airbase, those fly over my house at low altitude many times a day with F16 and choppers and what not.. Bluetooth is very limited in range, this all works at 2.4 GHz and at 5 GHz for video (and for some telemetry I use).
OT: Personal aircraft, vertical takeoff and landing
Started by ●August 9, 2018
Reply by ●August 10, 20182018-08-10
Reply by ●August 10, 20182018-08-10
Reinhardt Behm <rbehm@hushmail.com> wrote:> John Doe wrote: > >> For short trips, a helicopter might be ideal except for lack of >> safety. How can you add a parachute to a helicopter? You can't >> soar, so you are coming straight down if anything fails. > > It should be able to auto-rotate. Commercial helis usually can do > that. The landing is just a bit uncomfortable, not very good for > your back.Learn something new every day... "Helicopter full down autorotation in an Enstrom F28A" https://youtu.be/RupkHgbKTro "Helicopter Full Down Autorotation Bell Huey" https://youtu.be/BkF4b6OuXJ0 And last but not least... "Mosquito Air full down autorotation" https://youtu.be/z2U0p9N5hFY
Reply by ●August 10, 20182018-08-10
On 10/08/2018 00:22, gnuarm.deletethisbit@gmail.com wrote:> On Thursday, August 9, 2018 at 4:42:43 PM UTC-4, Lasse Langwadt Christensen wrote:<snip>>> Sailing - The fine art of getting wet and becoming ill, while going nowhere slowly at great expense (equivalent to standing in a cold shower, fully clothed, throwing up, and tearing up $100 bills, while a bunch of other people watch you). > > You are thinking of power boats. In a kayak you have to paddle as well! > > Rick C.And it's cold. You can't have your kayak and heat it. Cheers -- Clive
Reply by ●August 10, 20182018-08-10
On Friday, August 10, 2018 at 4:40:47 AM UTC-4, Clive Arthur wrote:> On 10/08/2018 00:22, gnuarm.deletethisbit@gmail.com wrote: > > On Thursday, August 9, 2018 at 4:42:43 PM UTC-4, Lasse Langwadt Christensen wrote: > > <snip> > > >> Sailing - The fine art of getting wet and becoming ill, while going nowhere slowly at great expense (equivalent to standing in a cold shower, fully clothed, throwing up, and tearing up $100 bills, while a bunch of other people watch you). > > > > You are thinking of power boats. In a kayak you have to paddle as well! > > > > Rick C. > > And it's cold. You can't have your kayak and heat it.No, you wear a wet or dry suit and then the problem becomes cooling. But that's an easy one, rotary cooling. We also call that rolling. Rick C.
Reply by ●August 10, 20182018-08-10
On Thu, 9 Aug 2018 21:13:59 -0400, bitrex <user@example.net> wrote:>On 08/09/2018 08:52 PM, John Doe wrote: >> gnuarm.deletethisbit@gmail.com wrote: >> >>> I thought the bulk of the weight in an orbital rocket was the >>> fuel? That's the big problem with rockets, it takes a lot of fuel >>> to get the fuel up to where the little bit of remaining fuel can >>> get the satellite into orbit. >>> >>> In other words, it's all about the fuel, fool! That's "fool" in >>> the same sense as stupid in "keep it simple, stupid". Don't want >>> anyone to think I am trying to insult you. >>> >>> I don't know VTOL is inherently contradictory. It's more a matter >>> of design goals. Will it be as efficient as a jumbo jet in fuel >>> per passenger, maybe not. But when you factor in the huge >>> inconvenience of transportation to and from airports it mitigates >>> a lot. So what are the requirements? I know in DC many would pay >>> extra to not have to go to the large airports. >> >> Depending on distance traveled... It will be more efficient, faster, and >> less hazardous than a helicopter or a multi-rotor. > >All VTOL aircraft so far have been exercises in compromise, there's no >known way to build such an aircraft with all the advantages of rotary >aircraft plus the speed and efficiency of a fixed-wing aircraft. Remind >me of what your gimmick is again that makes your concept have different >rules? > >And at least so far there also haven't been any aircraft of that type >which could be described as safer than a conventional plane or >helicopter, AFAIK pilots have described them all as "unforgiving" at best. > >> The inefficiency comes from the vertical movement of takeoff and >> landing. But that is temporary. > >The inefficiency primarily comes from the fact that to VTOL you want >your thrust vectored up and down. For efficient cruising you want your >thrust vectored 90 degrees to that. So at least naively your options are >either to build an aircraft with two sets of thrusters pointed different >directions which adds weight, cost, complexity, and inefficiency. Or to >build one that has a single thruster set that rotates which also adds >all the above (likely in some other proportion.) > > >> There are other possibilities, involving ultralight aircraft. >> >> Possible solutions, besides building the vertical-to-horizontal >> capability into the aircraft, include a platform for launching and >> landing. >> >Or brute force: https://en.wikipedia.org/wiki/Tail-sitter -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●August 10, 20182018-08-10
John Larkin wrote:>Or brute force: > >https://en.wikipedia.org/wiki/Tail-sitterThat is how my laser-arrow can do vertical takeoff: https://www.youtube.com/watch?v=8PONksCkJTI 160 km/h about 99 miles per hour. I tried to make it hoover.... no. https://www.youtube.com/watch?v=boe_foS4SlY
Reply by ●August 10, 20182018-08-10
On 08/10/2018 03:02 PM, 698839253X6D445TD@nospam.org wrote:> John Larkin wrote: >> Or brute force: >> >> https://en.wikipedia.org/wiki/Tail-sitter > > That is how my laser-arrow can do vertical takeoff: > https://www.youtube.com/watch?v=8PONksCkJTI > > 160 km/h about 99 miles per hour. > > I tried to make it hoover.... no. > > https://www.youtube.com/watch?v=boe_foS4SlY >The "Hoover" was a popular synthesizer sound in many commercial electronic music recordings throughout the 1990s <https://en.wikipedia.org/wiki/Hoover_sound>
Reply by ●August 11, 20182018-08-11
On Friday, August 10, 2018 at 1:53:46 PM UTC-4, John Larkin wrote:> Or brute force: > > https://en.wikipedia.org/wiki/Tail-sitter> John Larkin Highland Technology, Inc > picosecond timing precision measurement> jlarkin att highlandtechnology dott com > http://www.highlandtechnology.comAs my flight instructor used to say, "Taking off is optional. Landing is mandantory."
Reply by ●August 11, 20182018-08-11
John Doe wrote:> > Helicopters are very risky. Even a quadcopter crashes and burns if > one motor fails. A copter with five or more motors might be good for > short trips.20-something years ago there was a documentary on a guy whose dream was to build a quad-copter out of 4 rusty surplus transport copters and a square steel framework. He wanted it for logging, to replace a balloon IIRC. One copter failed and all 4 pilots came down. I don't remember if they all lived.
Reply by ●August 12, 20182018-08-12
AT Saturday 11 August 2018 18:34, Steve Wilson wrote:> On Friday, August 10, 2018 at 1:53:46 PM UTC-4, John Larkin wrote: >> Or brute force: >> >> https://en.wikipedia.org/wiki/Tail-sitter > >> John Larkin Highland Technology, Inc >> picosecond timing precision measurement > >> jlarkin att highlandtechnology dott com >> http://www.highlandtechnology.com > > As my flight instructor used to say, "Taking off is optional. Landing is > mandantory."A good landing is when the A/C comes down in one piece, a very good landing is when it can be used again. -- Reinhardt
