NASA's Greased Lightning 10-Engine Hybrid Electric VTOL Drone

[Jake Bullit]

An interesting design here from Nasa.

Don`t think we have a VTOL section,so I  posted it here.


http://www.engineeringtv.com/video/NASA-s-Greased-Lightning-10-Eng;Engines-and-Motors

[iPeel]

Awesome, came here for the thread title and was not disappointed!

A load more useful snippets too, not just the VTOL info.

[electrotor]

I see the tailplane tilts too, unlike other similar designs where the tail motor is fixed for vertical flight only.
There is no VTOL section because multicopters and helicopters, which have their own sections, are VTOL by nature. Maybe a new section is required for the convertiplanes. A few different designs have been linked on the forum over the years.

http://www.banggood.com/Unique-Models-LTV-XC-142-Tilt-wing-Experimental-RC-Aircraft-Airplane-PNP-p-1003834.html?utm_source=youtube&utm_medium=SKU302446-1022&utm_campaign=tommyre-edit&utm_content=tommy

http://www.4-max.co.uk/aircraft-ripmax-Ripmax-Transition-VTOL-ARTF-A-RMX200.html

http://www.rotormast.com/en/

There was also a tailsitter and one where the vto motors retracted after wing-borne flight.

[wgt40w]

The two points I found of particular interest were:

1) That the C of G is to the rear of the main wing - presumably to prevent changes to c of g being caused when the main wing rotates.

2) That in forward flight only the two outer / wing tip motors are used - to partially counter the inefficiency of wing tip vortices.
Most twin engined rc planes have the motors as close as the propellers diameter will allow to the fuselage.

I wonder if the NASA vortices at wing tip idea will cause a rethink on rc twin motor design ??

[iPeel]

I saw the Hobbyking one flying yesterday too, while at first I thought I was definitely going to die it did settle down in the end and flew really quite well.

[elmattbo]

The two points I found of particular interest were:

1) That the C of G is to the rear of the main wing - presumably to prevent changes to c of g being caused when the main wing rotates.

2) That in forward flight only the two outer / wing tip motors are used - to partially counter the inefficiency of wing tip vortices.
Most twin engined rc planes have the motors as close as the propellers diameter will allow to the fuselage.

I wonder if the NASA vortices at wing tip idea will cause a rethink on rc twin motor design ??

You're probably right. RC planes historically mirror full scale designs but in the same way pusher designs have changed single engine models, this may be another way to think about twins. On full scale aircraft the locations of the engines is partly dictated by the need to control an engine failure and the relationship between Vmcg and V1 (basically take off safety speeds). That's not something you really need to think about on an RC model.


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[elmattbo]

Oh and I think the cg to the rear is an efficiency design. A forward cg means that you have to counter the nose dropping by pushing down on the tail; more stable but not efficient as you increase the effective weight of the aircraft.


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[BigT]

https://www.facebook.com/344199252427633/videos/512085742305649/

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[electrotor]

The Tron/Kestrel must be one of the most mechanically simple and elegant solutions I have seen. Here's the video of what looks like a modified Twinstar testing the mechanism.

https://www.facebook.com/344199252427633/videos/vb.344199252427633/489469567900600/?type=2&theater

[electrotor]

Here's a more complicated solution to VTOL.

http://www.krossblade.com/

[Ratty]

That Tron one is a thing of beauty, my favourite so far.

[skyscraper]

Yes Tron .. Go to the top of the class there lads :)
Here it is on Youtube

[Coyote]

Thee Tron does look the most practical solution.