STUNT HISTORY!!!!!

I would wager that this is a first, and would also bet that old Dead George is smiling!

See Ya

After watching the a flawlessly flown pattern, walking back to the pits area, I was starting to feel a little sorry for the internal combustion engines: their days a numbered. But then I started my 40FP and its sweet sound snapped me back!

Outstanding! It would be of great interest if someone could post the motor, battery and prop used, the model's weight, and details for any special gagets, for example, motor on/of from circle center etc.

A noteworthy achievement!

... not to mention cost, which I'll bet was many times what a conventional (i.e. nitro fuel) setup would have cost...

I don't think electric will achieve wide popularity until it can be done at a more conventional cost... (I may be showing my ignorance, tho...)

Tim

Remember the source of this information. Peabody has the credibility of...well, I am trying to make nice so I will truncate this missive.

P.S Peabody if i would have gotten a 2nd flight i would have broke 500 points!!! Maybe at the GSCB fall airshow i can do better.

I don't know what you are afraid of, Mike. It isn't as if you are saying that the electric set-up is ready to challenge the PAs, Ro-Jetts, and Saitos for top dawg supremecy. You are dong ground breaking development work and having fun. Nothing wrong with sharing what you have learned. Who knows, if something like this can be shown to work, maybe an electric event will be started in the future. There are already profile and biplane events in some areas (I wonder if a Tri-plane would qualify for the latter?)

Let us know what you did. It could be fun to learn something new.

See? Sometimes Peabody does nicey-nice! He can put up a non-controversial post

Congrats Mike! Sorry we weren't there. We didn't get home from work until 4:00, figured we were too late to enter. We'll be waitning for the fall meet!

Mary

Would it be possible to rig slight throttle advance switch on the control system that would allow for a 2-4-2 type of run? If the plane will do the whole pattern with out throttle control and the 2-4 action can be controlled via the manual control system it would stay inside the established rules, would it not?

Just a thought..

Cost isn't cheap- $125 or so for the motor, maybe $50-60 for a controller, $40 for the battery, and $75 for the radio or IR setup to control it. Doesn't even compare with an LA 40 or 46- $60 for the motor and 10 for the tank. The LA will fly many planes a LOT better than the electric.

I see your point, but other's don't. As soon as you mention a successful E-stunter they assume it should fly as well as a pipe or 4 stroke setup (or it's not successful to them). They also bring up price. How much is a piped setup, or 4 stroke setup (engine, pipe, header, bolly props, fuel, glow plugs, ect..)? Well i know because i bought a piped setup a few years back, and i assure you my E-setup is way under that price. If you add up all the support equipment the price may be the same or even a little more, but all that support equipment is only bought once.

Look back at the last thread about my airplane. That thread explains itself and why i feel the way i do about posting on here. Alot of these healthy, good for the sport discussions get way out of hand! If people are truly interested in electric or have a comment worth mentioning post it. I will read it. If you want to hear my side or comments e-mail me, call me, send me a letter or talk to me at the field. Their has been quite a few people do this already. I'll be persuing electric stunt in the meantime.

P.S I might as well thank everybody for the positve comments. I may not post on here to tell you how much i appreciate them, but i do!!!

I for one think that what you are doing is amaizing and very leading edge! Keep pushing the envelope! Watching noisless air ballet was very awe inspiring.

How close are you to finding a polymer battery to suit your needs?
What was the reason for the throttle control? Did you have to advance the throttle as you got close to the end? Is that the reason? It looked like that Twister had quiet a pull.

I congratulate you on your success, and encourage you to continue!

(Did I say I would eat a bug or something if electric CL stunt succeeded? If so, I guess I better look for a bug..)

The fact that you are achieving a full conventional pattern flight is remarkable. Obviously, you are making the energy management work.

Now, I'd like to be constructive. I think it is time we recognize the great possibilities of Electric CL Stunt, but I think we need to define an appropriate event and rules, to make it more reasonable.

First, I think throttle control, through lines or Z-tron transmitter, should be allowed. This should permit but not require, both throttled takeoff, and shutdown for landing.

Second, I think the 2 level lap requirement between maneuvers should be relaxed to 1 complete level lap. The single lap could be slowed with throttle to preserve energy.

Third, although it would be neat to fly the standard maneuvers, triple repetition maneuvers might be modified to be two iterations.

Finally, we ought to take a look at revising flight pattern times slightly, if this will help.

I'm sure some of these might be wrong, and no doubt the pioneer achievers in this mode could make some better suggestions. I'd just like to see the effort encouraged and supported with a class and rules.

Maybe we can just begin thinking about it. Looks like there is plenty of enthusiasm already.

My sincerest congratulations!

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"If olive oil comes from olives, where does baby oil come from?"

What is the point in modifying the standard pattern if it can be flown unmodified? Mike proved that it can be done and even after the plane sat in the sun for hours. I am pretty sure the plane still had some juice left in it. When Mike was doing the landing maneuver, the plane was still developing power which slowed the rate of descent.

The point would be to recognize certain limitations for flying Electic STUNT, and make the event more viable in general.

If you preclude throttle control, for example, you remove a major method for managing the energy. With throttle control and 1 level lap between maneuvers, reducing speed just a bit will save a lot of battery power.

I'll bet that Mike's flying technique is very smooth and disciplined, and if I understand right, he's using a throttle (right?).

Perhaps I should allow the people actually trying to compete with these ships to make suggestions.

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"That which seems the height of absurdity in one generation often becomes the height of wisdom in the next." -John Stuart Mill

I don't think it would detract from the pattern, it might even be nicer (on the judges). The level laps could almost be half speed.

(I had discussed autonomous controls which would throttle down during level flight with some other interested parties.)

Manual throttle controls could have advantages for energy management in an electric stunter. For example, if the ship could be set up with more than adequate power available, max power could be kicked in only as needed for certain maneuvers, or perhaps toward the end of a flight as batteries started to sag.

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"I know some place you haven't been! .. I've been everywhere."

I offer two arguments that there is no need to decrease flying speed in order to save energy:

1) As the plane goes through a maneuver, propeller gets loaded more than in level flight. In order to maintain the same RPM's the current draw increases. As the plane goes back to level flight, the load on the engine decreases and so does the current draw thus providing a sort of 'autho-throttle' action.
2) The overall weight of the airplane is much higher than a conventional setup due to batteries. This will require higher speed to maintain lift. Also, if the plane is slowed down between the maneuvers, the energy required to accelerate it back to pattern speed would be significant and drain the battery.

Mike was talking with Tom Hampshire about the power train, and Tom seemed to be nodding in agreement...
I cannot even get my glow driver figured out.

But, take this to the bank: Mike accomplished a feat that I would wager no one else has, and he flew at a true Expert level. I'm still amazed!
See Ya

Stunt ships are by nature NOT very efficient - they are super draggy (motivation is lift, we haven't been too concerned with energy needs) and I'm not sure I buy the preservation of kinetic energy idea. I can't see a way that flying two level laps at the same high throttle setting could use less power than throttling down, because the energy requirements increase at a far greater rate than speed.

For an electric motor, power = torque x RPM, and armature current translates directly to torque. Granted, unloading the prop reduces current flow. But throttling down would help even more.

To get Electric Stunt to work, I'd wager that Mike has optimized several parameters, including his flying style.

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"What we obtain too cheap we esteem too little; it is dearness only that gives everything its value." -Thomas Paine

And, no, we are not trying to see if it is as efficient as a pipe ship or a 4-stroke (hey, let's get electric in here to compare, too, OK?) This is electric power with its limitations. But if the limitations are being overcome to make it a viable alternative power package, hmmm. Yes, a new event!

A potentiometer (variable resistor) would be a very inefficient power controller. It wouldn't have a chance of being workable. Modern controllers use electronic switching techniques, with power MOSFET transistor switches, and are much more efficient. These switches handle large currents and are almost "ideal" as switches, approaching zero resistance when on and infinite resistance when off. They can switch in microseconds.

A switching controller can improve efficiency by matching the current switching to the motor's characteristics. For example, there is typically an optimum contour for ramping the motor speed up. Note that torque requirements are a function of load, and the propeller needs to be well matched to the motor and thrust load (the same can be said for internal combustion engines we use).

Some extremely efficient (and expensive) "printed circuit motors", (which are sophisticated stepper motors), with special drive controllers are available, and being used in electric sailplane events. I'm not sure they would be practical for CL Stunt. But these people build electric sailplane ships that stay up for hours, even days at a time. They do it by using the motor to get altitude, cut the motor (the prop folds), and then riding thermals, etc. until they need to repeat the process. Completely different from stunt!

The whole problem remains the energy density (total energy/weight) of batteries, compared to other sources like alcohol or kerosene. Batteries are getting better all the time, but they are still heavy and the best batteries are not cheap. (Laptop computers seem to be helping drive battery technology..)

I'm extremely impressed with Mike's achievement. I'll guarantee that it is considerably more difficult than it might appear, and he knows a great deal about it by now.

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"We are born naked, wet and hungry. Then things get worse."

Yes, the above quote was from me on thread #31. Now I find out that there already is an event for Electric Control Line Precision Aerobatics in the rule book, listed as event 607.

Paragraph 3.4 in the Electric section states any motor is allowd, but the battery pack is limited to a maximum of 30 Nickel Cadmium cells. Line sizes and pull test requirements are specified. Same maneuvers as our PA event, though it appears the points for each maneuver are not specified nor is there any reference to the PA pattern description/scoring. Solar cells are not allowed.

I wonder how many of us were aware of this. I wasn't

I was also told that the Blacksheep Squatron out in the left coast area (my term, sorry, guys) have held electric control line contests for years and have held the aerobatics event. However, I am not aware if anyone has done a complete patter in one flight. (Anybody know?}

This is certainly not to minimize the accomplishments as posted in this thread. It is certainly a great accomplishment to produce an electric powered plane capable of performing the complete aerobatic pattern, and then to achieve the high score that was awarded the flight.

But, as with any pioneering event, and with rules already in place, it looks like this is something that could eventually become commonplace.

OK, guys, the podium is yours.