Mike Parsons

Greg,
What is the reason for the dual rudder setup? Are you getting blowback? I would imagine even on a 33% that a single 8611 would be plenty.


There is nothing like seeing that much juice in one photo
-Mike

Greg Covey

Mike,

On a similar size plane, Quique uses three 8611 servos so my dual servo setup is a more practical compromise since the Hangar 9 Edge 540 is already set up to handle the second servo.

The extra torque of the dual servo setup provides several functions for 3D flying.

First, it makes the rudder more responsive by being quicker under force. This allows for more precise hovering and 3D maneuver control.

Second, if the rudder ever touches the ground on a tail drag maneuver, it has the torque to reposition the entire plane, if needed.

My installation went well but I am concerned about the 5" length Titanium Pro Links. I really can use a 5-1/2" length but I don't think JR makes them. The 5" rods only screw into the ends about 1/4". It may be time to make some custom steel rods.

Mike Parsons

Makes sense. I have to remind myself about the sheer size of this plane as that escapes me at times. I forget that many 33%'s are indeed ganging two rudder servo's for that very purpose.

-Mike

Greg Covey

I found a solution to making the linkage 1/4" shorter. I noticed that the control horn swivel was actually aft of the hinge line so I reamed the hole for the threaded rod towards the front and re-positioned it. Since the threaded rod could now move slightly backward, I filled the gap with epoxy and a plywood splint.

The 5" Titanium Pro Links seem to be threaded well now and match the rest of the plane's control surfaces.

On to battery pack mounting...

"I've got enough Lithium in the plane to light up a city block!"

Darrell B.

Greg,

May I ask what has prompted you to reconfigure your battery packs?

Looking great as usual.

Thanks,
Darrell

algutkin

My Feedback: (1)

It's time to make this baby fly. Like NIKE says "Just do it" In my opinion, every change weakens the project. How many test pilots have bought the farm as a result of testing engineering conclusions and ideas. The unexpected will always happen, sometimes trying to engineer around some perceived problem, just makes the potential problem a real problem.

Greg, if you let some 3D pilot test the craft and it has a problem it's going to be blamed on the builder. So, take a chance, fly the bird, test the bird, build another better bird.

One cent worth from

Al Gutkin

Greg Covey

Hi Darrell,

There were several reasons for reconfiguring the packs. First, the cells I have are no longer sold by FMA and they were not properly configured for safe cell balancing. By reconfiguring the cells to 2p "super cells" and then making 4s and 6s packs, I could then wire a BalancePro HD pigtail onto them for compatibility with the balancing charger and DPM. I can now safely charge the packs in the plane at a 2C rate and have discharge protection during flight. In this new configuration, the packs will continue to operate safely within the limitations of the weakest cell. Lastly, I needed two 10s setups, one per motor, to retain opto-isolation for each Jeti 90-amp ESC per Jeti's recommendation.

Al,

It won't just be any 3D pilot. It is Devin McGrath who won the EX Games in Toledo and placed 3rd in the Blaine Austin Extreme Aerobatics Championship in Memphis. Don't worry though, we will have a graduated test plan starting with a simple flight test with the DPMs disabled.

The plane is now valued at $6000, so I need my "t"s crossed and my "i"s dotted.

algutkin

My Feedback: (1)

Hey Greg,

It's a slow weekend here in So. Cal, and it's been raining every weekend for almost two months, today included, talk about cabin fever. Anyhow, I just can't resist posting a comment here and there, and laughing while doing it. LOL Hope you have room for a smile.

Engineers think differently than most other people, not bad, just different. Software engineers are especially guilty of this. It seems that the projects are never declared "finished" and they just drag on forever. The project financer is frustrated, the employees are frustrated, and the technology has changed dramatical before the project is finished. For example NASA.

Having been involved with some of the largest public corporations in the country, I have found that they have adopted a different way of thinking when it comes to filing tax returns. Do it any old way, we can fix it later, or better still, let the IRS fix it. Now, adapting that psychology to RC aircraft building and flying is easy. Plan it, build it quickly, drag is out, test it, fly it, make another better one. NIKE got the idea, "Just Do IT". However, at a FMV of $6,000, and all being considered, the financing of this project should be the part that is engineered.

If this research project is self financed, my thinking would be, to get sponsors, charge admission, or think about getting a second job. You might think about selling advertising space, don't put those stickers on without being paid for the space, Axi Motors, Kokham Batteries, Opti Controllers, Edison, Du-Bro, Devcon, and I would even think about charging Devin McGrath to fly it, because it's gonna be a thrill.

Al Gutkin

Greg Covey

Al,

The one nice thing about a hobby is that is doesn't have to make sense, it just has to be fun.

We have nice weather here now but life keeps getting in the way of my R/C testing. Events like the Toledo show, seminars, Easter weekend, Jury Duty, and trips to FMA in Maryland have me stealing hobby time when I can. I dream of being retired in 12 to 15 years so I can keep busy with R/C and stay senseless.

KatManDEW

My Feedback: (6)

Holy moley. I'm just finishing up a electric powered 34% Extra, for radically less money than that, with some bells and whistles.

algutkin

My Feedback: (1)

Oh, the wine last night was really good, check the time of this post. LOL... Greg, I'm on a mission to become more in the way of being retarded, before retired. How am I doin so far?

Kat, I'll answer for Greg...Fair Market Value does not equal actual cost.

If we keep nagging Greg he will eventually install the prop, tighten the prop nut and attach the spinner, charge those new battery packs, plug in the Deans connectors, turn on the transmitter, turn on the aircraft switches, and see how much torque, wattage, and duration is being developed. Darren doesn't even need to be there, just a camera man (or a camera wife). We all know this can be accomplished in the family room without the wings attached.

Al

Greg Covey

Kat,

In case you missed it, "Part 2" was the low cost conversion which still cannot be beat today. The 3000w burst AXI/Jeti power system for $500 set the industry standard for giant scale electric conversions. You can purchase a NEAT Fair 2005 video for seeing the results.

I was able to do my initial CG check before mounting the battery packs and was happy to see that the plane was nose heavy. The dual AXI motor weight and 10-ply motor box added sufficient weight up front to allow my battery packs to be mounted in the main fuselage area. This will make recharging easy by removing the two canopy screws. The BalancePro HD system will provide a safe 2C charge rate while keeping the packs inside the plane.

KatManDEW

My Feedback: (6)

Nope. I didn't miss it. 3000 burst watts isn't worth doing on a plane this size. And $500 was just the motor/ESC, wiich is not comparing apples to apples.

I'm using the single motor/battery/ESC solution with 5700 watts burst, at about half of $6000, (without any bells and whistles).

Greg Covey

Kat,

In your opinion perhaps, 3000 watts isn't sufficient power but I think it is safe to say that you are in the minority as it has been used successfully by countless others. It also fits in the general rule of thumb guidelines developed by Keith Shaw decades ago.

You make no sense when you say that $500 was just the motor and ESC which is not comparing "apples to apples". I clearly stated that it was for the Jeti/AXI power system.

I'm not sure what your presence here in this thread is accomplishing. It is unlikely that you are using quality components like a Hangar 9 33% Edge 540, JR 8611 digital servos, BalancePro HD system, etc, so your 1/2 cost application is a good case of "apples and oranges".

Over here at RCU, we have less conflicts than RCG as people stick to there own threads without attempting to post "look at me" statements. You are welcome to start your own thread in this forum as many of us want to see different solutions.

KatManDEW

My Feedback: (6)

Sorry to have ruffled your feathers Greg. Still sounds like a Spruce Goose to me. I'm out of here.

algutkin

My Feedback: (1)

Greg,

All kidding aside, you and the others that pushed the electric revolution are greatly appreciated. I think most of us get it, about the comparitive cost factor, but you know, that doesn't really matter. What matters is that it takes special people like you to push the envelope and try new things. I'm not sitting here watching the progress of the 540 because I want to emulate it. I'm watching your progress in order to learn more, and to get ideas for a similar combination that can be used in a giant scale aircraft.

Greg, you are one of primary people that makes up the research and development department for electric aircraft. You appear to treat your activities in a very professional manner and someimes even take it beyond serious. Don't forget, most of us are hobbiests, some of us are anal, some of us can't fly worth a darn, some of us are highly educated and some are dumber than dog stuff, some like to brag and argue, some can't afford to replace a broken propeller and some are so serious that they have chosen this hobby over thier family.

I know you are not used to people upsetting your build threads, I read them all many times over. When this bird flies, I really would like to see you in the picture with a smile from ear to ear. All of us can't make perfect planes, all of us can't fly like Kevin, all of us can't figure the power requirements without lots of experimentiation and some ugly failures, but, we all can laugh at ourselves and make this a fun hobby. Heck Greg, your reports are what brought me back to this hobby after a long absense. I forgot, how much fun building airplanes was and too think that electric motors can now power them as good as petroleum products.

I just have one question regarding the project, how you can test out the power part of the project with the prop and spinner laying on the carpet?

Al G.

Anyhow, if you don't like anything I post, email me, and it will evaporate. But, I'll still be there watching and smiling

Greg Covey

Al,

Kat is a good guy and we have known each other for many years back when I was an E-Zone moderator. My point was not that my feathers were ruffled but that my thread was going off topic. Too many threads lose their information focus in off-topic white noise. RCG is notorious for that level of diffusion and I like to think RCU sets a better standard. Members should start their own project threads so everyone can either benefit from or help out.

As for your question, I likely did not fully explain my train of thought. My goal on the first CG check was to see where I stood for balance by putting the 4 Lithium packs in appropriate places without mounting them. Since I have a new dual motor, custom plywood mount, two ESCs, a larger prop, and a second rudder servo, I really had no idea where I was anymore for balance. Previously, on my last AXI power system, I had two smaller packs Velcro'd up front on the PVC motor mount. After my initial CG test, I was nose heavy (for the first time without packs up by the motor mount) but close enough to obtain proper balance by swapping the 4s and 6s packs around.

My next step, after properly securing the packs, is to create two serial adapters for connecting the 4s and 6s packs in series to the ESC. I will then test each motor out, one at a time with the prop installed, and then both together. The current can be measured between the output of the serial adapter and the input of the ESC to check the power level with the Mejzlik 26" prop.

Below is my last Edge 540 power test using the Tail Trap from JL Power Products. It allows me to safely test big power systems without the need of an assistant.

algutkin

My Feedback: (1)

Greg,

With that much power, don't stand in front while testing. Projecting out your work load, and available free time, when do you estimate flight testing will take place?

Al

mustang11

Greg,
In the relatively near future I plan on starting a Top Flite giant scale P-47 which I'd like to electrocute, and to that end do you believe the 3000 watt power system in part 2 would be sufficient for an approximately 27 pound bird, or should I think along the lines of what you're doing here in part 3? Now the obvious, I'm not looking for 3D performance, just a well performing bird that'll hold it's own with most anything out there. I've probably answered my own question with the 3 Kw choice, but I'm curious to hear what your thoughts are on the subject. Thanks, Larry V.

algutkin

My Feedback: (1)

Me too Larry,

Greg, you started it, what are you thinking? Is this the way to go, or, should we start thinking in a different direction for heavy RC aircraft.

Al

Mike Parsons

3000 watts on a 27 pnd plane is 111 watts/lb. Plenty for good long straffing runs with accelerating victory rolls. That equates to around 3.9 hp. 100 watts per pound makes for a very well powered sport flyer and 150 w/lbmakes for excellent 3d, so you will be somewhere right in the middle.

algutkin

My Feedback: (1)

Mike:

Am I reading correctly? The power setup in Part 2 is ample for a 27 lb. plane? Don't need to do the duel Axi setup in part 3?

Al

Mike Parsons

Al,
In my opinion that is correct. The dual AXI that Greg is using now is for extreme power solutions (will probably yeild Foamy performance in this plane ). I am always game for more power, but in a warbird or civilian aircraft, 100 watts/lb to 120 watts/lb is what I shoot for.

-Mike

algutkin

My Feedback: (1)

MIke:

Thanks, I thought that I had the basics of electic propulsion down, but then after reading the part 3 conversion I was getting confused. I started thinking that the RC aircraft industry didn't have motors large enough to fly heavy airplanes. I thought the twin Axi setup was something revolutionary.

I also started thinking that my theory was incorrect, supply more volts you get more RPMs. Because adding more motors in line, doesn't automatically get more RPMs. Am I correct in my understanding that the purpose of this twin motor modification is just to enable the swinging of a larger prop, larger than a single motor could handle, thus, more batteries in parallel. I can't see how the twin motors would enable more RPMs, if the volts stayed the same as a single.

Al

Mike Parsons

In respect of Greg's thread, I would like to take this conversation to another thread. It is a good dialog, however I dont want to dilute Greg's information so it will be easier to follow.

-Mike