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Old Sep 10, 2008, 02:07 AM
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Some 3 engine VTOL designs


Here are a few of my designs that I did several years ago that I have finally been able to do in CAD. I designed the first one initially to use DynaCam engines, but unfortunatly that company is no longer. After I got that one in the computer, I decided to play around with it a little and came up with the other three.

Comments are welcome.

Brian.
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Old Sep 11, 2008, 02:56 AM
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Might want to look into http://www.rcvengines.com/rcv120sp.htm RCV engines as it sounds like a similar design.

Just remember the 3rd motor will need to rotate to counteract its own torque effects.

Scott
Old Sep 16, 2008, 11:02 PM
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Actually, when I originally designed this thing i was thinking full scale. 2 place airplane a little bigger than a LongEze with three DynaCam engines at 200 horsepower and 650 ft/lb of torque. DynaCam folded and is now owned by Axial Vector Engine Corporation. See http://www.axialvectorengine.com/index.html and look at the video on the front page.

I just did a search and a little research to find that out. Was wonder what happend to DynaCam.

Brian.
Old Oct 08, 2008, 04:52 PM
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Quote:
Originally Posted by Tuner
Might want to look into http://www.rcvengines.com/rcv120sp.htm RCV engines as it sounds like a similar design.

Just remember the 3rd motor will need to rotate to counteract its own torque effects.

Scott

(I've never had a edf or df but from what I've heard...)
If you made the back prop it a ducted fan it shouldn't have torque roll. It may have a intital twist but once it's going it should be fine, shouldn't it?



I might try a simular one of those designs sometime...




Glider-man
Old Oct 08, 2008, 10:04 PM
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Does anyone think that the designs with the motors pointing up will be more stable. Because your thrust will be coming from highing in the plane which would act like having a lower center of gravity.

I see it as if your motor is pointing down your plane will be top heavy because your thrust (The thrust seems to be the blance point for VTOL) will be comming from below the prop which in your case is below the plane. This is why I think people are struggling to make rc harriers, (or turbine/ DF VTOL) because they're top heavy. (real ones are full of 1,000,000 $ computers)

What you could do is turn one of your pictures in vertical take of position 90 degrees anticlockwise and pretend it was meant to fly like that,- you'll see that the ones with the motor pointing down will become pusher planes which in my opinion are more unstable/harder to fly...


Just what I think, you may disagree but it seems strange that only VTOL with props have really worked well in RC, you can't point a turbine/DF upwards now can you...
Old Oct 09, 2008, 04:58 AM
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(I know that those plans were meant for full size but they would make some awesome rc planes! )


Now...

Would the motor at the back need to have twice the power as the two in the front? (I've never done VTOL before need some help) You hear lots of people talking about Vtail mixers in VTOL... what do they do for VTOL?

What I'm trying to do is have a simple VTOL plane with hopefully no gyros...
Old Oct 14, 2008, 01:42 AM
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Glider,

Not sure on HP ratings with that particular configuration. The design is an old one that I did on paper quite a few years ago that I translated into CAD more for my enjoyment than for a practical aircraft.

I have been playing around some more and came up with this new 3 engine fan design. So far I have not drawn it in vertical flight yet, but with the fans closer toward the CG of the aircraft, it would probably make for a more relistic VTOL than having them spread to the far extremes like the other one.

Brian.
Old Oct 14, 2008, 08:49 AM
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Quote:
Originally Posted by cougar1969
.. but with the fans closer toward the CG of the aircraft, it would probably make for a more relistic VTOL than having them spread to the far extremes like the other one...
Really you would want the fans at the extremes, that would give a longer moment arm for better control, similar to why your control surfaces are at the extremes. Unless your going to put puffers at the extreme for control.
Old Oct 14, 2008, 04:35 PM
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Max,

Thanks for pointing that out, something I never considerd in a VTOL design. I will have to do some modifications.

Brian.
Old Oct 22, 2008, 01:31 AM
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A few changes on the last design. I moved the engines out do to Max's observations. I like it.

Feel free to post comments.

Brian.
Old Oct 24, 2008, 04:11 PM
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Vt


Hi again ,

I've never used a gyro or done VTOL before, so to get a steady take off do you need you motors to be even or can the gyros make the plane go up/down evenly?
Old Oct 25, 2008, 12:46 PM
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Beats me Glider, I have never build a VTOL RC either. I was just throwing out a few designs to get the juices going.

Brian.
Old Dec 02, 2008, 02:37 AM
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nice design cougar. Would be nice if we could get some ideas of how to actually tilt the edf units. I have a few ideas, but would be nice to see what other ppl come up with.
Old Jan 01, 2009, 03:43 PM
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Quote:
Originally Posted by kahloq
nice design cougar. Would be nice if we could get some ideas of how to actually tilt the edf units. I have a few ideas, but would be nice to see what other ppl come up with.
Ok you get something like a DX6 or DX7 radio and have the motor connected to a switch on the radio so that when you flip the switch the motors turn to VTOL and you have 3 gyros in the plane connected to another switch to turn them on when you flip the switch for VTOL or connected to the same switch so it will hover perfectly when u flip the switch but say if your going fast and you flip the switch you need to have the motor setup so that when you apply rudder the bottom of the motors will tilt a direction so that the plane steers that direction. Same thing for the side to side and forward backwards movement. Now last you set up the motor trust with the throttle on the transmitter. Now your ready to fly but make sure the your plane has it set up so that in flight that your motors dont turn your plane but STAY STRAIGHT. You still need to have alieron, elevator, and rudder for flight just like a normal plane. Last for hovering you need to adjust the three gyros on the plane so they dont under or over correct the plane. Now the three gyros arent for each motor but to help the motors and servos work together. 1 for the roll, 1 for the forward backward movement, and one for the rudder part of it that steers the plane while hovering.
Now when the plane is in motion not hover and you switch to hover give some back elevator imediately to prevent it from nosing into the ground then once it starts to come to a stand still back off the elevator slowly. Remember when your giving back elevator in the transittion to also suport the roll of the jet. Have it set up so that when your in hover and you give some alieron that say if you give it right alieron have it set up so the right motor slightly slows but when you do that its going to turn(rudder) to the right so give left rudder to counter act that movement. Same for the left alieron.
Hope this helps.
Last edited by wildcatfan42; Jan 01, 2009 at 03:53 PM.
Old Jan 02, 2009, 06:55 PM
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The DX6 and the DX7 do not have enough mixes to allow all of that.
As for prgramming the different mixes, I have something different in mind and I am using a JR9303 2.4, so there is a lot more mixes available.
But, for tilting the fans, i was refering to the actual setup to MAKE them tilt...the physical part. I was trying to get input and ideas from ppl on how they would attempt to make the fan unit itself move/tilt on an axis of some form.


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