Does going to electric flight now offer some changes that were uavailable with ic engines? I'm specifically wondering if both multi engine and canard stlye get a favorable Boost with the new electric system. some of the canards i've seen always seemed to suffer from whereto flip the prop,while multiengine model, especially 1/2a suffer from engines being able to run together.
I also thing the batteries and equipment might be a step towards having a stable c/g during the whole flight.
I'm wondering what others think.

I saw Paul Walker's new, redesigned Impact at the recent NW Regionals. He certainly took advantage of some of the things electrics offer and was able to move the battery back almost over the center of gravity.

Truth is, I don't think that electrics are really superior to IC. But the one thing they offer that makes them extremely attractive is repeatability. Every flight Paul flies is the same as the last (as far as engine run). The ability of the the setup to adjust to variable loads perfectly every time is just awesome. I have had engine runs with IC that are as good, but I've also had some that were terrible. Paul doesn't get terrible runs. That makes the system incredibly attractive. And when I re-finance my house so I'll have the money, I plan to get into it. But it's still very expensive to get a setup like Paul's.

In Philly I've watched Mike Palko doing electric for years. Sickening. Consistent run flight after flight. Now Jack Weston's doing it. They're smug. Electric works. Sorry to say. I hate electric. No big time engine crackle when they fly. No burnt castor smell in the clothes... Perhaps the dental drill motor screech will make them mad.

So how cool is electric?

Yesterday we took out another test plane, a Vector ARF.  Did the assembly, Programmed the ESC and did some pre-flight tests in the garage one evening.  At the field I set it for a 2 minute test flight.  My Nephew told me to set the static RPM for 10,500 for a 5.5 sec lap time on 63' lines.  He missed by .1 sec.  The 2 minute flight showed the bird needed just a hint of flap tweak, leadout position and tip weight looked OK, and we have turn to burn.

Flight 2 we set for 6 minutes and started committing CLPA.

Yeah electric is REAL cool!

Also,

Fuel Proof Paint is not required.  That opens up some areas in finishing that could lead to lighter weight finishes.

Jim Pollock   

I agree with many of the comments made so far. Electric is about on par with IC. The consistency may nudge it slightly ahead? Either way electric cannot and will not dominate for for quite a few more years. With better technology and some engineered designs electric may start to offer the edge it takes to win.

Dennis Moritz needs to fly electric! His mushy ARF profiles have held up his progress for the past two years. Horrible engine runs drown out the electric flights at the home field. I get tired watching him struggle with sour engines runs. Maybe I will force him to fly one of my airplanes this summer........ Maybe not........ 

When flying my Mustang the prop noise on the ground is quite loud at full throttle! Once the motor settles to flight RPM is is not so bad and in the air the noise is a slight hummmm. As Randy said the square corners give you a great sound.

Mike   

I can tell you that holding Paul's Impact XLE, the thing about drags me around the circle. Tremendous amount of thrust is generated.

Electric in and off itself does not deliver a winning advantage. I tend to see it the same as the difference between 2 and 4 strokes, you can take care of your business with either one. In the RC F3A world where you can REALLY assess it's high level competitive capabilities, it's really a wash. A YS DZ 170 up against a full blown Plettenberg setup comes down to the pilot as usual. It is very similar to the scenario in modern day frontline fighters. One side makes a big technical jump. The other side catches up. Parity is achieved and they end up going back to WWI style phone booth dogfighting.

I have personally met people who for some reason or another simply cannot master stunt motors. Dave Fitzgerald could remove his PA 75 setup out of his plane and give it to them and man,I tell you, they would screw it up!!! I think the electric just may be the savior for them.  I personally would not hesitate use them to grind out practice flights in a sensitive community situation.

I question the engine run. Those that run IC engines work to maintain a good run and no over run. Electics are programed. No overun! Why in competition is the advantage given to electric. Seems a bit unfair considering the hoopla when Windy used a timer. Any comments!
Thanks
Wayne

I question the engine run. Those that run IC engines work to maintain a good run and no over run. Electrics are programed. No overrun! Why in competition is the advantage given to electric. Seems a bit unfair considering the hoopla when Windy used a timer. Any comments!
Thanks
Wayne

Hi Wayne,

Certainly in FAI F2B there is no restriction on the use of a timer to stop the engine. The problem is much more complex however than it first appears.

The Electric setup:

1. When you "start" the motor you are at the same time starting the timer countdown. The two are in sync and will not result in a flight running short or long. It will run exactly to the preset duration.

2. The mechanism to actually shut the motor off is just some logic in the chip. Logic weighs very little. No other physical apparatus is required. The power for this comes from the flight battery and so there is no additional weight penalty incurred.


The IC setup:

1. Assuming you have implemented a timer, you would have to decide whether to manually start the timer before flipping the prop (and taking a chance that the engine did not fire immediately with a resulting shortened run) or manually initiating the timer after the engine had started (with the possibility that the time taken since signaling the timekeeper is longer than what is required to shut off and land under the time limit)

2. You will need to determine an effective means of stopping the engine. A partially shut off engine will run lean, cook the engine and put you over the time limit. If you are racing this might not seem like much of a risk. In stunt a good motor is a pretty valuable commodity.

3. You will need some physical means to make the engine shut off. Let's assume you will pinch the fuel line. You will need a battery, a servo, a timer/device to control the servo, a method of setting/initiating the timer, access to all of the components (the battery will need to be removeable), access to the fuel line from the servo and a device to hold the fuel line while you are pinching it. This will weigh a fair bit and will need to be located up close to the nose of the plane. (C of G issues)

Alternative IC Setup:

Learn how to manage your engine run properly like all of the top fliers do and meter the correct amount of fuel. (there now that was pretty simple Eh?)


Kim   :-)

Next year if the votes pass, you won't have to worry about the line pull test.  They will all be the same.

Hi Alan,
   Your comments may be controversial, but they may also be true. I have said since my first electric pattern in 2003 that electric is in the stage of life that the glow engine (forget spark ignition) was way back when. Look how bad the performance was in the IC early days and compare it to how good the performance is with electric already! This is using off the shelf R/C items, not purpose built like many of the IC engines are for PA. It is scary to think what could be possible in the next 10-15 years and I look forward to it.

Mike

Fine. Never said that it wasn't worth doing. I wouldn't question progress just how things get stepped on going up the road.
Thanks
Wayne

To question IF electric power is the equal of IC or better is the same as wondering if shaving the corners off of nickel shaped wheels would be an improvement.

Kim. 

Alan,

I guess thats the problem with writing to a multinational audience. Our nickels used to be twelve sided.


So I will now restate this in AMERICAN English (oh the poor Queen)

To question IF electric power is the equal of IC or better is the same as wondering if dry paint is an improvement over wet.


Kim 

In reference to Dennis Mortiz’s 6/18 note about the Electric Smoothie crash at Brodak's June 13.  I actually clipped the ground at the bottom of an outside loop, surgically removing the vertical fin.  The plane continued smoothly around up to about ten feet, stalled and went in nose first due to lack of airspeed.  The main parts of the plane stopped shortly before the landing gear, battery, and ESC stopped.  The pilot sustained no injury.  The spinner was already modified similar to the Adamisin Oriental.

Mike Palko was not encouraging when I showed him the battery.  I didn’t even touch that plane for over a month after returning home.

After the extended period of indecision, reconstruction cautiously began.  It took a whole two or three hours.  In addition to the battery, the ESC had smashed thru the firewall, which had been modified for wiring and ventilation, and posed no resistance.  Battery damage turned out to be cosmetic.  There is now a clearer path for ventilation.  The motor “feels” different, but performs just fine.

What it is:   Brodal ARF Smoothie, 50 oz. (ugh).  Tank area modified to accommodate the ten oz. EVO 11.1 volt, 3.3 amp Li-Po battery, shoved way back into altered cockpit area.  Rimfire 35-48-1300 motor.  APC 11.5X4 gas prop.  Viper 60-Amp ESC.  Will Hubin FM-1 timer.  BP Hobbies charger (as advertised in MA, August, pg.15)  Flight time 5.5 minutes, 5 to 5.2 second laps, using 27 amps, about 75% of the battery.
 
All I need now is to learn how to fly.
 
      Dave

About the paradigm....

It won't shift fully to electrics until electric motor's are on a power level equal to a PA ROJ 75,76 or higher and the weight of an AT .36.  That's when there will be no choice whatsoever; that you must have electric to even be remotely competitive.

Jim Pollock, seems reasonable to me.......    

Alan,

Granted Igor's electric wasn't too far behind David's IC PA .75 and if Paul could have kept his together a while longer the story there could have been different.  I guess we won't know for sure until Paul brings out his next XLE and avoids the bird swarms.

Jim Pollock  Look out  it's a bird!

I see your question as being more of a statement.  The short easy answer is yes, e-power airframe designs can go places that are difficult to do with IC power.

The longer answer like WHAT changes - that will take a little longer to re-sort!  At the present just about all the electric airplanes flying are conversions of designs for IC.  E-power has certainly proven it's viable.  Next step will be the purpose-built birds, designed to take advantage of the cleaner installations, engine braking and ability to move the battery closer to the CG. 

I personally do not think canards will ever be better stunters than conventional layout, but electric surely makes it easier to try, and someone will prove or disprove the capability of a canard.  BTW have you noticed that almost everyone who talks about electric power also talks about TWINS?  I think electric designs will in time be substantially distinct from IC designs...

Well here are a few of my thoughts to the “E” revolution and design specific airframe requirements that I see at this point in time (no doubt things will need to change as batteries and “E” motors evolve).

Airframe Layout: I don’t see any advantage to pushers and canards at this time. But a delta wing may have some advantages by reducing the mass of the fuselage (weight).  My Delta Force, although IC powered, flies extremely well for an un-flapped model and has the fuel tank located on the C.G. It shows very little difference in trim from the beginning to the end of the flight. 
 
Wing Design: Not much of a shocker here from current practices, but slightly thinner airfoils to reduce the drag of the airframe.  However, a strong wing is still required mostly because the all up weights are not much different from IC powered models.  I-Beams may have an advantage at this time with their generally lighter construction (more on this later).

Fuselage: This is where I think most of the changes will come to the forefront on “E” models.  The fuselage can be built without much or very little plywood reinforcement and eliminating the maple engine bearers.  More molded fuse parts such as top & bottom blocks, molded from thinner balsa stock and/or molded C/F parts.

Tail & Moments: Still, not much reason to change these except to help balance the model with the possible exception of building them lighter to make up for the lighter “E” motors.  Another option is to lengthen the nose to arrive at the proper C.G.

I am of the opinion that the closer the battery pack is to the C.G. the better.  Also, I think the battery pack should be located as close to the vertical C.G. as well.  This is where I think the I-Beam wing design allows the pack to be placed closer to the vertical C.G. without degrading the wing structure by cutting through the wing spars and center section sheeting.  I know there are other ways around this but this seems to be the best choice at this time without adding additional weight.

I started crunching numbers and doodling on the computer to see just what I would come up with an “E” PA stunt design, and so far, it still looks like a Magnum or a “G” Force <LOL>.  But I will keep at it a see where all this leads me.

Mikey

Actually I don't think there is a lot of "R" in the R&D on DC electric motors. Basically it comes down to producing the strongest and cheapest (and heat resistant) permanent magnets.

The real R&D is in battery or fuel cell technology. That's where the future development is coming. The motors are really already pretty darn good.

Electric motors are trivial in their technology compared to the IC engine. Also IC engines are a pretty mature technology (been around on the scale of 100 years). I am not too sure what else you can do.

I agree that the Fox 35 will most likely be a survivor---sort of like cockroaches!!

Seems to me the paradigm shift towards electric is already apparent, with the electric technology getting better while the IC technology is fully mature with less likelihood of improvement. After all Mike Palko finished 8th at the past NATs in a Bob Hunt designed Mustang, sized for a PA61. Very, very, close to a top 6 finish. Mike's system is dead reliable while providing a high level of performance. One remarkable aspect of Mike's system is the straight forward conventionality of the approach. Components are off the shelf, but well matched.

Yesterday we took out another test plane, a Vector ARF.  Did the assembly, Programmed the ESC and did some pre-flight tests in the garage one evening.

Dennis could you provide the setup on the ARC Vector and how it came out weight and performance-wise. I've been pondering a setup like this.

Ted,
from my limited experience thus far what you say is the direction I approached it from. One of the things we are dealing with now is that most of the people are using airframes that were designed for IC engines. for example, my P-40 flew with an LA 46 , the engine weighs about 8.6 oz plus a small muffler. Then the fuel tank as well. I in fact ended up with the battery forward of the CG to balance the beast.
 Now on my new bird, I did the math and extended the nose a small amount which allowed the battery to live much closer to the cg. The one thing that has to be considered is that the battery is so heavy it dramatically affects the vertical CG. On my new bird dihedral allows the battery to find a happy home closer to the vertical cg. The AXI  motor I am using weighs abotu 6.5 oz. the batteries are about 14 oz. I will in fact have some room to move the battery forward and back to adjust the cg. Another thing I found was that by the battery living on the outside of the fuse (profile) I was able to take out most all of the tip weight.
one of he things of concern is accelerating the mass of the battery around corners if its to far away from the cg. Or so is my feelings. I dont know of any of the gents flying electric that are just placing the battery flat out on the cg.

I'm curious why some feel one advantage of the electric is the ability to put the battery somewhere around the CG. (snip)

Placing a heavy battery over the desired CG location (around 25% MAC)  means that more dead weight would almost certainly have to be placed up around the much lighter motor to get the CG to its optimum location.  The only other option would be to make noses very long so that the airplane would balance correctly without adding dead weight behind the motor.

What am I missing here?

Ted

p.s.  Never having held an electric motor equivalent in power to a modern .60/.75 IC engine I might be all wet here.  Does the electric motor weigh more than a equally powerful IC engine???

Ted:
You are of course completely correct about the CG-trade-off.  No real advantage to moving the battery back to the CG unless you can also make the tail weigh less and/or the nose longer to still hit the CG. 

Digging a little deeper, the  heaviest E-power component is the battery, and in most set-ups that is roughly located where the fuel tank would be - meaning its moment arm is shorter than the motor.  For "big power", I think PW's original set-up uses a very large/heavy battery which compelled him to work some magic to get that mass closer to the CG.  Mike Palko's Mustang designed for similar power level uses a lighter battery in a more "normal" arrangement.  I believe Mike also uses an adjustable battery tray so he can fine tune CG.  In both cases PW's & Mike's birds weights are similar to most 75 sized IC birds - its a break even.

My new bird has the battery on a tray to move it over about a 2" range for CG refinement.  I do not have what Mark suggested, and that is a means of adjusting the battery VERTICALLY for vertical CG.

You KNOW what size bird and power level I like!  The complete power package in the Swinger weighs about 13 oz and delivers power of a strong 40.  Weight-wise it is competitive with a 35-40 size IC power system, especially when you include the weights of motor mounts & such.  It is perfectly feasible to use this power set-up in a Classic sized bird and still hit a Classic weight target of around 40 oz.

My new Classic Typhoon will use this power system, with the battery located as low as possible to control the vertical CG, and as far forward as possible to emulate the old unmuffled McCoy 40 I used in 1969.  Looks like the battery will be nearly UNDER the motor in the middle of the chin scoop, hopefully with some fore-aft adjustment room...


Addendum:
I see way back in post #2 I said something about moving the battery closer to CG: the context for that statement was the E-Oriental conversion which as built was a little noseheavy.  However, I am now using a 2 oz lighter motor, and 3.5 oz lighter battery.  A "new" Oriental could easily weigh 5 oz less with all of the weight loss ahead of the CG.  Thus CG issue could easily swing the other way!  Still, there are no plans to convert the Oriental to the lighter package; it flies fine as is and I'd rather spend my efforts on NEW stuff.