RC Groups

RC Groups
    VTOLs
        Discussion Lockheed Martin Various

#1 sherifx Dec 28, 2012 02:36 AM

Lockheed Martin Various
 
So guys, I've been a lurker in these parts for a little bit. I came here because I've always been in love with VTOLs since I was a kid. I think they're an ingenious solution which has never had it's chance to truly shine.

I had the idea that I wanted to bridge my quadcopter's abilities with an EDF jet for a long time now, but I've been taking my sweet time trying to sort the details out in my mind.

Then low and behold, Lockheed comes out with news that it's basically doing a tactical version of my exact idea.

http://www.youtube.com/watch?feature...&v=vUpMG-KN7Pg


So what can a lowly guy like myself do? I do think the principle is easy enough, however transitioning from VTOL to forward flight is always a challenge, and is an EDF capable of producing the trust necessary to transition in this manner? Even the retractable doors are easy enough.

I'd love to hear some opinions about what Lockheed is doing and if there is anyway to replicate a vehicle with similar abilities using hobby-grade parts and preferably without the need for a liquid fuel, keeping it all electric and hopefully most obviously, smaller than a tactical grade UAV haha.


Warm Regards
Sherif

#2 VTOLicious Dec 29, 2012 09:03 AM

1 Attachment(s)
Quote:

Then low and behold, Lockheed comes out with news that it's basically doing a tactical version of my exact idea 
Hi sherif, please let us know your "exact idea" first!
Obviously Lockheed engineers are not forced to use off the shelf hobby articles for their designs, hence a RC-VARIOUS will require a completely different design approach.

Cheers, Michael

#3 Brandano Dec 29, 2012 01:58 PM

The concept is hardly new, just reworked and adapted to a stealthy frame: http://en.wikipedia.org/wiki/XV-5_Vertifan

#4 VTOLicious Dec 29, 2012 03:53 PM

2 Attachment(s)
Quote:

Originally Posted by Brandano (Post 23652360)
The concept is hardly new, just reworked and adapted to a stealthy frame: http://en.wikipedia.org/wiki/XV-5_Vertifan

Indeed...and already in the 90s Northrop Grumman transformed the fan in wing idea into a low observable airframe design!
Further more in 2011 a picture of NGs MUVR concept appeared. Seems the fan-in-wing idea is still alive ;)

http://www.aviationweek.com/blogs.as...b-9f16def13c63

#5 RCvertt Dec 29, 2012 11:07 PM

Quote:

Originally Posted by sherifx (Post 23638859)
...I'd love to hear some opinions about what Lockheed is doing and if there is anyway to replicate a vehicle with similar abilities using hobby-grade parts...

I don't think so. It's possible but it'll have a flight time of a couple minutes at best. If you keep the doors off and tilt the fans 90 degrees for a stealth version of an osprey then you'll be in business.

#6 sherifx Dec 30, 2012 09:26 AM

Wow, I'm impressed with your knowledge of history guys. It does seem like the Various is basically the Vertifan with the pilot taken out and rebodied in stealth airframe.

Sorry I should have clarified but RCvertt got the gist of it. I was thinking about how to recreate this using hobby grade parts. I liked the idea in theory primarily bc you have the best of both worlds, you can VTOL, however you ultimately have a highspeed airframe that you transition to like the Harrier or VF35. I thought (rather simply) that this would be a fun idea at the hobby grade level bc it could be a lot simpler with an electric platform and the BOM would be quite a bit less. One could theoretically program a flight controller to be in bi-copter mode providing stability and then with the flip of one of the channel switches, coordinate and transition to forward flight using the same sensors (gyro, accel) to allow for a stable transition. However, there is a lot I don't know about RC airplane design still and the weights that we usually deal with in multi-rotors would likely not be acceptable at the same size and scale with airplanes (my 650mm frame can be upwards of 2.4kg AUW).

I suppose longer flight times could be possible with a larger airframe and a turbine vs an EDF, but then I'd be getting in way over my head.

#7 Brandano Dec 30, 2012 12:22 PM

I think that once you remove the constraint of having a pilot in the loop, then the tailsitter works out as the best approach. In the case of a military vehicle the next obstacle is managing the payload, but it's relatively easy to solve, especially when using internal bays.

#8 PenJo Dec 30, 2012 05:10 PM

Maybe, just maybe, itīs possible to do it without custom controller programming.
So basic task is to control crossbreed between classic airframe and bicopter multicopter and use offshelf hobby components for it. Cheap ones preffered :)

What about to install TWO cheap kk multicopter boards in one airframe, one kk board loaded with bicopter sw and one with openaero firmware for aircraft stabilizing. Airframe could be just simple delta (or anything else) with two props in wings (bicopter part) and tractor prop and elevons (aeroplane part). Both kk boards controlled by different channels, mixes done in transmitter (i īm using open9x so i can have multiple flight modes and mix any input controls to any output channel(s)).

Flight modes could look like this:
1) hover - active is only board with bicopter fw, throttle going only to bicopter kk board
2) transition - both bicopter and openaero boards active, some portion of throttle mixed to tractor prop
3) once some forward speed gained, switch to standard flight - kk board with bicopter fw disarmed, full control and throttle to aeroplane board.

I have seen quad copters with additional tractor motor installed flying just fine, so maybe this can work. And it's just something like to place quadcopter in the middle of the flying wing (it has been done) but with different controllers for quad and wing parts.

just an idea ...

Pen

#9 RCvertt Dec 30, 2012 11:32 PM

Quote:

Originally Posted by sherifx (Post 23659123)
...I liked the idea in theory primarily bc you have the best of both worlds, you can VTOL, however you ultimately have a highspeed airframe that you transition to like the Harrier or VF35...

You also have the worst of both worlds. Two lift fan motors, props, and door mechanics and servos that sit there as dead weight for most of the flight time. I think it's worth building though. I just finished my first V22-Osprey and the thing has to fly really fast to stay in the air during forward flight. The ship you linked to might perform better if the right parts are picked. Looks like there is more wing surface area on this aircraft then on the Osprey.

Stability and transitions will be the easy part compared to getting a decent flight time due to how heavy it will be.

Those little 1300kv blue wonders can spit out 400 grams each with the right prop. If you think you can build the plane at about 600 grams ready to fly then it might work.

#10 sherifx Jan 02, 2013 11:17 PM

RCvertt and Pen, I've been thinking about this ad nauseum today, watching birds fly and so forth and I wonder if there isn't a better solution. I also spent time thinking about the VJ101, and I think I'm on to a better train of thought.

Could you design a plane, featuring rotating high anhedral wings and forward mounted EDFs. For take off, the wings would flip vertical and the EDFs could blow air over the ailerons which would aide in VTOL control and then it would transition to forward flight in the same way an Osprey or the VJ101 would. This would reduce parts which would not be used during forward flight as the vertical component is secondary to the primary of forward flight. In effect, a tilt-edf.

Thoughts?

#11 Brandano Jan 03, 2013 02:31 PM

Would work pretty well for ducted fans, but it would be more complex for turbojets, due to having to handle hot gases. It might work with turbofans, with the control surfaces only immersed in the cold flow. Essentially it would be like the Doak VZ-4 (http://de.wikipedia.org/wiki/Doak_VZ-4) or a twin duct version of the Bell X-22 (http://en.wikipedia.org/wiki/Bell_X-22). Notice that in the Doak the pitch control in hover is achieved deflecting the turbine exhaust in the tail, tilting the fans won't do anything.

#12 RCvertt Jan 03, 2013 02:52 PM

Something like an EDF osprey is the way to go. I looked more at the Various and the lift fans in an RC version would have to be much larger than theirs are in order for it to get off the ground.

Quote:

Originally Posted by sherifx (Post 23695402)
...rotating high anhedral wings and forward mounted EDFs...

I'm not sure what you mean by this.

There should be no need for a moving surface behind the fans depending on the design.

#13 Lapino Jan 04, 2013 09:54 AM

What about thrust vectoring for the v-22 like mounted engines? There are some cheap solutions available at hk ;-)

#14 sherifx Jan 04, 2013 01:02 PM

I'll put together a few sketches of ideas for you guys as a reference point so we can all be on the same page regarding the design.

As far as rotating high anhedral wings I meant the following: The idea was a whole wing which would rotate, not just the motor (one of many different options), so I figure the wings would have to be mounted high on the fuselage. The anhedral component would give a negative (vs neutral or positive) angle to the wing (when looking at it from the front) which should add some maneuverability to the higher wing mounting point. The theory behind this idea, for me, is that with the edf unit mounted in the wing vs at the edges it would always blow air over the control surfaces hopefully giving more control at different flight speeds as well as using the control surfaces for thrust vectoring when vtol'ing.


...now as I think of it... You could even place the rudders by the motors instead of in a conventional location with this setup, no?

#15 sherifx Jan 07, 2013 12:49 PM

1 Attachment(s)
Something like this. I think a picture helps to extend/add dimension to the discussion....


All times are GMT -5. The time now is 11:06 AM.