THE WAR ON ALUMINUM, MARCY 2 IDEAS

AIRFRAME OPTIMIZATION HELL

Mainly, going from something that flies to something worthless hoping to someday get something more efficient flying again. The fact is Marcy 1 didn't have enough lift to do what She needed to do.



Got a wing from a discontinued glider to try to improve Marcy 1's efficiency.











It looks horrible compared to the beveled sheet & it's heavier. Everything needs to grow to balance it. You need a bigger balance beam to counteract its moment of inertia. It has to be bolted. It has unnecessary winglets since we have full cyclic control. It takes full power to get off the ground & quickly falls back down.





Went back to a glued balsa sheet but an enlarged balance beam. The best monocopter is completely glued even if every broken propeller & crash is a rebuild.

That got no meaningful improvement. The larger balance beam didn't improve attitude stability either. It's not loss of lift but loss of reserve power for translation. We as hover experts don't think she has enough attitude control to hover using sonar.

Also got rid of the inductor & relied on software instead. It's actually bearable with all the filtering required for attitude sensing.

The next step is a steeper angle of attack. Angle of attack changes require rebuilding the entire Marcy 1 but it's no worse than what goes into mocking up a human rated aircraft.







The steeper angle of attack was a disaster.

Despite your intentions of achieving fixed wing efficiency out of a rotary wing, a monocopter still gets most of its lift from just the outer part of the wing. People usually make it fatter on the outside or hang it on a long boom. Next comes longer wings.





That did slightly better in the wind, climbing even with full cyclic, but we're out of calm weather until next month. Going longer means no indoor use, so next comes going wider. A wide 1/16" sheet might actually work.





Undoubtedly going to require a longer balance beam to overcome pitch. This actually seemed to work well, but there's no such thing as a calm day in Calif* in April. Can get maybe 20 seconds before she's blown down the golf course.





THE WAR ON ALUMINUM

Next, the war on aluminum nuts continues.



Any threadlock completely destroys the prop. Down to plumbing tape & just letting it strip.


Overall, the Marcy 1 program sux.

MARCY 2 IDEAS



Been thinking of a long duration hover vehicle using 2 large monocopters bolted to a fuselage or a larger monocopter for outdoor use, but some people still get excited about tri rotors. Don't feel another tri rotor is advanced enough to call a Marcy vehicle.

Long duration hover requires a larger lifting area than any propeller or helicopter rotor can give. Pitch would involve differential thrust. Roll would involve throttle modulation from Marcy 1. Yaw would involve differential roll. Bearings would come from the Corona parts.

This would give 6 degrees of freedom from only 2 PWM's. Marcy 1 gets 3 degrees of freedom from 1 PWM.

It would need 3 batteries & 3 full duplex radio links to the ground. 2 would control the monocopters which would use beam cutoff sensors instead of magnetometers & no thermopiles. An IMU on the fuselage would detect attitude. They wouldn't need balance beams.

1st step is flying a big monocopter with a larger battery, motor & a dummy balance beam. That would prove longer flights were possible.


It's hard to justify the amount of work going into thermopiles if no future vehicle is going to use them. With the payload limitation & open space requirement, Marcy 1 is never going to do more than POV lighting at night. Monocopters can't bank enough to counteract wind because their magnetometers lock up.

When the weight of the monocopter is factored in, she doesn't get much more thrust out of the motor than a bare propeller. A bare propeller + flap would probably do better but couldn't do POV.

So it's heading back to the original plan of Marcy 2 as an indoor tri rotor & Marcy 3 as a VTOL Predator. Marcy 1 would be a toy for POV, maybe autonomous but more likely manual.






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T3
Comment by Krzysztof Bosak on March 26, 2010 at 12:30pm
Excellent, the only thing I am afraid of, you are doing fundamental research in too many areas, without proper scale of financing.
Comment by Michael Zaffuto on March 26, 2010 at 7:19pm
Hi Jack...I got to thinking about the statement of not more thrust than the bare propeller and started thinking about what could be done to get the lift efficieny up. I thought about the Willar Custer, cool old school designer aircraft designer from the 50s , and his channelwing design. http://www.rexresearch.com/custer/custer.htm

This plane is the Custer CCW-5. In any event, The high speed air over the airfoil creates super great lift. He was demonstrating fixed wing airplanes that could mostly hover! The last picture is the Hanno-Fischer innovation to the design where the prop is in its own duct, has a cross beam for strength and some flaps for control.

So I was thinking.....I wonder how much lift you get if you were able to somewhat duplicate this structure using an electric ducted fan and place it in the wing.....probably closer to center than not..seems crazy...but you never know!

Admin
Comment by Morli on March 26, 2010 at 7:54pm
interesting!! never seen or heard of that one. thanks Michael
Comment by Michael Zaffuto on March 26, 2010 at 8:13pm
Hi Morli, check these out...cool NASA updated concepts using channel wing lift concept:

http://www.youtube.com/watch?v=XnuL_0MBn7c&feature=channel


http://www.youtube.com/watch?v=OrAqPC1vdfI&feature=channel


"It's the speed of the air, not the airspeed"

Admin
Comment by Morli on March 26, 2010 at 8:41pm
:)) , still reading CCW concept this ,looks like will still be reading probably for next one week at least , thanks Michael, for the vid of nasa concept , how is the engine torque compensated in this( first video)? by default twist/angle in vertical fin ? I would have thought the folding wing upwards would have been better but what would I know more than nasa!!
How true "It's the speed of the air, not the airspeed" & " Fly slow is difficult than flying fast" :-))

I always wonder Jack
Why is the prop so small in Marcy?
What if the prop is mounted on the main slate ? is it some thing to with increasing centrifugal force as the RPM increases?
why can't another better brand/model of prop be used instead of fighting with the quality of prop that gets clewed so often?
Comment by Michael Zaffuto on March 26, 2010 at 10:09pm
Here's what I was imagining:


Admin
Comment by Morli on March 26, 2010 at 10:23pm
what if the motor/rotor is moved outwards? doesn't it translate to less load, or smaller required size for same output?

Comment by Michael Zaffuto on March 26, 2010 at 10:31pm
The wing lift due to rotation might be balanced by the rotor/motor lift if placed in just the right spot...I agree..the farther in its, the more that motor would feel the inertia of the wing and need to be bigger...my first thoughts were that it would have an enormous vertical lift and needed to be as close to center to keep the wing from tipping up...

Admin
Comment by Morli on March 26, 2010 at 10:47pm
i think, the closer it gets to center , the blades on inside will face lesser forward air leading to differences & to other differential complexities, which smaller blades for smaller motor towards the edge may cope well. but you are right, a sweet spot would balance i guess. I wonder what should the direction of prop rotate? how would it effect other wise is another interesting question? :)
Comment by Michael Zaffuto on March 26, 2010 at 11:05pm
One aspect I was thinking about was that if high lift was attainable at relatively slow speeds...within the order of servo reaction time...either the motor speed or the flap/elevator directly behind the motor....or an included actual aileron could be controlled in sync with the thermopile 'attitude' output for either wing leveling or purposeful cyclical tilt for directional control. Tilting down in one half circular plane and tilting up for the second half of the circle for some percentage of forward 'lift' thrust.

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