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Old May 01, 2012, 08:57 PM
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Tama, Iowa USA
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Originally Posted by Paul J. Harris View Post
Staggerflyer,

I placed the order for the ARF today. This will be a big step for me as the largest aircraft I've flown so far is 52.5" on an E-Flite Power 32, 4s battery.

Wondering if you are still happy with your choice of the Rimfire 120? Noticed another poster went with Power 110 on 8s. Haven't seen it fly, but wondering if that is true overkill? Only advantage for me would be to continue acquiring 4s batteries and run them in series versus acquiring 5s batteries. Additionally, posted photos seem to indicate that you were able to cut a smaller hole in the dummy engine for a more scale appearance that the Power 110 allowed.

Any new thoughts on your project in its second season?

Regards,

Paul
Paul,
If you've never flown a large scale model, you will be in for a surprise. They are actually very much easier to fly! Smoother and more stable.

As for the power, yes, I am very happy with my choice of the Rimfire 120. I'm using 5 cells, 5000mah Blue Lipos. I've actually gone to a less pitch prop, a 17x8 to slow it down. Speed is not proper, nor wanted for this model. The Power 110 is definitely more than necessary for this plane, as Big Lacy mentions. over 60% throttle might tear the top wing off. Pure vertical till out of sight though. I do have another model with the Power 110, on 8 cells, the Great Planes P-6E Hawk, spinning an 18x10x3 blade prop. It never sees full throttle except on pure vertical, which is almost never done. The Rimfire 120 rarely ever see full throttle, either, by the way.

Get your batteries from Hobby Partz if money is a problem. Excellent batteries at good price. Gens Ace now a step up from Blue Lipo. I am very happy with my Blue's.
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Old May 01, 2012, 10:23 PM
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Raleigh, NC
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BL and Staggerflyer,

Thanks for the additional input. As I see it, battery placement is the biggest challenge for this conversion. The hatch project scares me as I am great at hacking up such undertakings. BL, I would be interested if you have posted any additional pictures of your battery placement in the forward cockpit, perhaps taken from behind the upper wing? Did either of you consider any other battery placement ideas? I have seen another similar model where the modeler inserts the batteries through the firewall with the cowling off. This has the advantage of preserving the scale look of the fuselage, but just how much trouble is cowling removal to change batteries?

Is there any possibility of inserting batteries through the bottom wing with the wing fairing plate removed? I know I will be able to answer a lot of these questions when my box arrives. Just brainstorming.

Paul
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Old May 02, 2012, 05:51 AM
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Tama, Iowa USA
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Quote:
Originally Posted by Paul J. Harris View Post
BL and Staggerflyer,

Thanks for the additional input. As I see it, battery placement is the biggest challenge for this conversion. The hatch project scares me as I am great at hacking up such undertakings. BL, I would be interested if you have posted any additional pictures of your battery placement in the forward cockpit, perhaps taken from behind the upper wing? Did either of you consider any other battery placement ideas? I have seen another similar model where the modeler inserts the batteries through the firewall with the cowling off. This has the advantage of preserving the scale look of the fuselage, but just how much trouble is cowling removal to change batteries?

Is there any possibility of inserting batteries through the bottom wing with the wing fairing plate removed? I know I will be able to answer a lot of these questions when my box arrives. Just brainstorming.

Paul
Paul, it is harder to remove and reinstall the cowl on this model than it is to make the hatch. MUCH harder. Once the cowl is on, you won't want to remove it. You will, but you won't want to.

BL was able to place his batteries further back because the
power 110 is much heavier, plus it requires 8-9 cells, vrs the rimfire, which runs on 4-6 cells. any other placement requires balancing (dead lead)weight.

Ultimately it's up to you. I will post more detailed pics if you would like, of the hatch area. I like mine. It's only noticeable when close up. I built mine to be seen in the air, and from stand-off distance, not close-up, full-on scale competition.
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Old May 02, 2012, 09:33 AM
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United States, FL, Orange Park
Joined Oct 2006
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Sold Waco!!

Quote:
Originally Posted by Paul J. Harris View Post
BL and Staggerflyer,

Thanks for the additional input. As I see it, battery placement is the biggest challenge for this conversion. The hatch project scares me as I am great at hacking up such undertakings. BL, I would be interested if you have posted any additional pictures of your battery placement in the forward cockpit, perhaps taken from behind the upper wing? Did either of you consider any other battery placement ideas? I have seen another similar model where the modeler inserts the batteries through the firewall with the cowling off. This has the advantage of preserving the scale look of the fuselage, but just how much trouble is cowling removal to change batteries?

Is there any possibility of inserting batteries through the bottom wing with the wing fairing plate removed? I know I will be able to answer a lot of these questions when my box arrives. Just brainstorming.

Paul
Hi Paul, although I sold my Waco,it was to a friend,and I can take more pic's when I see him.It's on display right now but will be flown again soon. If you check my first posts in this thread of the factory set up at seff,I went w/ first pics,that I posted. So I cut the hatch in as far reward as I could in front of the forward cockpit. Balances dead on. It will actually hover tho not scale at all. BL
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Old May 02, 2012, 12:44 PM
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Thanks again for the feedback, guys. Once I get my hands on it I will let you know how I plan to proceed, if there aren't too many other questions, first!

Paul
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Old May 09, 2012, 11:09 AM
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Raleigh, NC
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Ship Has Come In

Now that I have received the ARF kit, I am very impressed with the overall quality of this model. Before accomplishing any actual assembly, I need to determine how I am going to mount the battery and what servos I am going to use. I would like to switch to digital, metal gear Hitecs, as I have a programmer. However, I am pretty sure I would need to install CC's 20 Amp BEC Pro to handle six or seven digital servos going all at once. I wonder how the additional draw of digital servos will effect flight times using Gens Ace 5s5300? Any feedback on this subject greatly appreciated.

As I understand it, Big Lacy put his series batteries in the forward cockpit to offset the additional weight of the Power 110 motor. Staggerflyer dropped his straight down behind the firewall by creating a hatch, and presumably, that worked well with the Rimfire 1.20 that I will probably use. I am working on a compromise that involves a 'hatch' cut in the 'floor' of the front cockpit with ramp that will slide the battery at an angle forward and down against the firewall. The CG of the battery will not be quite as far forward as Staggerflyer's installation, but he did feel that he was nose heavy. If I have to add weight to achieve balance I don't have a problem with that as I do not intend to fly this model 3D. I will post some pictures of this installation when I get a chance.

I am planning to use APP connectors (75 amp) on my 5s batteries and the ESC. Since this is my first venture into giant scale EP, I should probably build a Safety Plug from the connectors, but I am not familiar with accepted practice for wiring this. Presumably, it is just an interruption in the positive lead to the ESC? If using the onboard BEC then all power would be interrupted, but if using an external BEC, then the receiver and servos would be powered as soon as the battery is connected, but the ESC would not come online until the plug was installed?

Thanks for any help,

Paul
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Old May 09, 2012, 06:16 PM
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Tama, Iowa USA
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Quote:
Originally Posted by Paul J. Harris View Post
Now that I have received the ARF kit, I am very impressed with the overall quality of this model. Before accomplishing any actual assembly, I need to determine how I am going to mount the battery and what servos I am going to use. I would like to switch to digital, metal gear Hitecs, as I have a programmer. However, I am pretty sure I would need to install CC's 20 Amp BEC Pro to handle six or seven digital servos going all at once. I wonder how the additional draw of digital servos will effect flight times using Gens Ace 5s5300? Any feedback on this subject greatly appreciated.

From what I understand, digital servos do draw a lot more than analogs. I do not have enough flightime recorded on any of my planes to know exactly how much time I have available. Have not run any to even near cut-off, yet, and am nearing the ten minute mark on a couple different ones. But, I would guess that you are going to be near that number with what you are planning.

As I understand it, Big Lacy put his series batteries in the forward cockpit to offset the additional weight of the Power 110 motor. Staggerflyer dropped his straight down behind the firewall by creating a hatch, and presumably, that worked well with the Rimfire 1.20 that I will probably use. I am working on a compromise that involves a 'hatch' cut in the 'floor' of the front cockpit with ramp that will slide the battery at an angle forward and down against the firewall. The CG of the battery will not be quite as far forward as Staggerflyer's installation, but he did feel that he was nose heavy. If I have to add weight to achieve balance I don't have a problem with that as I do not intend to fly this model 3D. I will post some pictures of this installation when I get a chance.

I am planning to use APP connectors (75 amp) on my 5s batteries and the ESC. Since this is my first venture into giant scale EP, I should probably build a Safety Plug from the connectors, but I am not familiar with accepted practice for wiring this. Presumably, it is just an interruption in the positive lead to the ESC? Correct. If using the onboard BEC then all power would be interrupted, but if using an external BEC, then the receiver and servos would be powered as soon as the battery is connected, but the ESC would not come online until the plug was installed? Just wire in the BEC behind the Safety plug, on the ESC side, so that lead does not recieve power till the plug is installed.

The safety plugs I use are made by MPI/MAXX. They are wired so the plug is on the positive line. However, it really is more correct to wire the plug in the negative line, as DC current actually flows FROM the negative TO the positive. This would eliminate the sparking on connection, as well as any electrons getting to the electronics until the plug is installed. (This is how all modern, ie 1985 or so, automobile electrical systems are wired now, to prolong switch and motor life. Same with sensors and computers in vehicles.)

Thanks for any help,

Paul
Read the red.
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Old May 09, 2012, 08:34 PM
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Raleigh, NC
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Just wire in the BEC behind the Safety plug, on the ESC side, so that lead does not recieve power till the plug is installed.
Duh! Of course. Thanks for the wakeup call on that one.

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Originally Posted by Staggerflyer View Post
The safety plugs I use are made by MPI/MAXX. They are wired so the plug is on the positive line. However, it really is more correct to wire the plug in the negative line, as DC current actually flows FROM the negative TO the positive. This would eliminate the sparking on connection, as well as any electrons getting to the electronics until the plug is installed.
I looked at those safety plugs, but they only seem to come in 14 and 12 gauge wire using APP 45 amp connectors. The CC 100 amp ESC has 10 gauge wire, as do the Gens Ace 5s batteries I have ordered. By placing 12 gauge in as the plug, I feel like I'm making more of a FUSE than a Safety Plug. <g> I am planning to install APP 75 amp connectors on the 10 gauge wire, and I have ordered enough of them to see if I can build my own safety plug with 10 gauge wire. I'll let you know what I find out.

Don't see why I could't place the safety plug on the ground side (black lead) and even use black APP housings and 'hide' it in the front cockpit.

One new question about the motor mount. I have noticed that the firewall is canted with right thrust, but does not appear to have any down thrust. Did you simply make all four dowels the same length and are happy with the trim situation like that? Did you mount the dowels on a set of the hole marks on the firewall, or did you have to interpolate? I'm planning to use the same motor you did.

Regards,

Paul
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Old May 10, 2012, 10:17 PM
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Tama, Iowa USA
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I kept the thrustline of the firewall. Do not seem to have any problem with ballooning on power changes, the reason for downthrust. I also setup to use the original centerline on the firewall, no changes. Used the "X" mount to drill the holes directly on the square stand-off for the gas engine. Then mounted the dowels as usual, which kept the prop drive washer in the proper position/location.

The 45amp rating on the mpii power plugs is plenty, as the max time over that during a flight is less than ten seconds, which occurs in less than 1 second bursts. Highest amp draw time is during runup on take-off run, and lasts less than 1 full second. So, even if they are "slow blow" fuses, they never get warm, soo... However, they do act as a type of efficiency reducer, as any and all connections and wire size reductions tend to do. As we are overpowered and do not require anywhere near max sustained output the loss is negligible/unnoticed.
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Old May 11, 2012, 09:46 PM
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I kept the thrustline of the firewall. Do not seem to have any problem with ballooning on power changes, the reason for downthrust.
Understood.

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Originally Posted by Staggerflyer View Post
I also setup to use the original centerline on the firewall, no changes. Used the "X" mount to drill the holes directly on the square stand-off for the gas engine. Then mounted the dowels as usual, which kept the prop drive washer in the proper position/location.
Okay, this is where you lost me. 'Setup to use the original centerline?' I also guess I don't understand the purpose of the square stand-off. Why wouldn't you put the dowels directly on the firewall?

Paul
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Old May 13, 2012, 07:05 AM
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Tama, Iowa USA
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Originally Posted by Paul J. Harris View Post
Understood.



Okay, this is where you lost me. 'Setup to use the original centerline?' I also guess I don't understand the purpose of the square stand-off. Why wouldn't you put the dowels directly on the firewall?

Paul
The square stand-offs are the pieces in the kit used for mounting the gas motor. I used them mostly to keep my dowels short, and to give a good solid footprint.

By "original centerline" I mean the one imprinted on the firewall. It is set up to put the prop drive in the center allowing for the thrust offset. Center your "X" mount on that location, mark and drill your screw holes, then when your prop drive is at the recommended distance, everything will line up perfectly. No need whatsoever to re-engineer anything. If you will look closely at the pics of mine and Big Lacey's firewalls, you can see the factory markings giving the centerline.
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Old May 13, 2012, 12:30 PM
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Staggerflyer,

Following you now. Servos and power system coming this week, so I'll be getting started, soon.

Paul
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Old May 13, 2012, 09:45 PM
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Have fun. It's a great model. Mine made it's first two flights of the year today.
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Old Jun 03, 2012, 02:29 PM
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Raleigh, NC
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Well Underway

Well, guys, I finally have enough progress to post some of my implementation of the electric conversion of this great model. I'm lazy, so I went with the same basic power system as Staggerflyer, RimFire 120 on a 5s lipo. I wrestled a long time with battery placement. I really didn't want to cut a hatch in the cover in front of the front cockpit, knowing I would really goober it up. I also didn't want to lay them out in the open in the forward cockpit like Big Lacy did. There is nothing wrong with either approach, but I wanted to try something different. Here's what I cam up with:

Picture 1: I cut an opening in the floor of the forward cockpit.

Picture 2: Looking through the opening, and through the bulkhead to the back of the firewall, you can see a slight lip running across the back of the firewall. Note that the opening in the bulkhead has had the lower corners squared to provide the rear support for the battery box, which will be inserted at about a forty-five degree angle.

Picture 3: This is the battery box shown at the approximate angel it will be at once in the model. The vertical support will bolt to a bulkhead in two places. It has 75 amp APPs secured to it.

PIcture 4: Battery box shown with battery secured and connected. Leads shown are for a battery charger. Installation will have 10 gauge wire.

Picture 5: Battery box about to go into forward cockpit. Actually, you have to insert it through the lower wing opening and assemble the rear post once inside the fuselage.

Picture 6: The battery box has a blind nut in the surface that lies against the back of the bulkhead. The bolt near the bottom of the firewall engages that blind nut and secures the battery box in place against the firewall.

Picture 7: Once the battery box is installed, the battery slides over the back edge of the forward cockpit opening and into the box, shown partially inserted here. I'll probably make a plywood hatch with a pilot attached that is secured by Velcro.

Picture 8: Once the battery box is installed, the battery slides over the back edge of the forward cockpit opening and into the box, shown partially inserted here. I'll probably make a plywood hatch with a pilot attached that is secured by Velcro.

I have no idea how this is going to work out CG wise, but will probably put as much electronics as far forward as I can. Even if dead weight is necessary, I'm not too concerned, as I don't ever intend to fly this plane in any manner other than scale.

Paul
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Old Jun 03, 2012, 08:45 PM
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Tama, Iowa USA
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Looks very nice, Paul. I wonder if you will have enough cooling to the battery? Check temps after first flight. I had to open my air exits behind bottom wing a little more, cutting the monokote between the ribs underneath.
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