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View Full Version : Need Juice for a Jug---P-47 That is.


Grasshopper
04-02-2006, 05:24 AM
Hello,

I'm awaiting the arrival of an E-Flight P-47 and need some assistance. Since I'm new to all this electric stuff, I need some help with a list of items I'll need to get her in the air. I've got a clean slate to start with as I will need to get an entire system. I'm looking at the Spektrum DX6 system and would prefer to use the motor that comes with the P-47 (480 w/ gearbox). I won't be installing the gear but will most likely add the rudder function. What batteries and ESC should I use? It looks like LiPos are the way to go but then what charger would I need? I also have a Cox Micro P-47 still in the box and would like to be able to use the same charger for it if possible. Is there anywhere I can get a list of items needed?

This may be a pretty broad request and I'm sure there are as many systems as there are pilots out there but I would like to narrow it down as close as possible.

Thanks for your help.

Tom

Sky Sharkster
04-02-2006, 06:27 AM
Hi Tom, welcome back! The E-Flite P 47 is a little bigger than the typical "400" size Warbird so the packs and speed controller will be a slight bit larger, too. I'd say a Castle Creations "Sprite" 25A ESC ($45.00) would handle the load pretty well. A 2100mAh 3S Lipo should provide enough power but you'll likely need 15C or better with a "480". The most popular charger now is the GP "Triton" it'll charge LiPo, NiMh and Nicads. As the LiPos have started adding "balancing" plugs you may want to look into a separate balancer with plugs to match your choice of battery brand. There are also charger/balancer combos available, one that got a good review is the "CommonSenseRC" unit, they also have good prices on batteries. This is a LiPo-only charger, you'd need another charger if you plan to use "round cells" also.
http://www.commonsenserc.com/page.php?page=intro.htm
These chargers will work with smaller batteries for the micro planes. You may have to set them for a different cell count (LiPo) or charge rate (mAh) but it's not difficult. Also, with smaller batteries most flyers use the smaller connectors like Deans micro or JST's while the bigger batteries generally use Deans Ultras so you will have to make up a couple of adaptors. Again, no big deal, just a little soldering practice!
You may be happy with the brushed "480" for a while but I see a brushless motor in your future! If so, you will need a brushless ESC also. The same batteries and charger will work for either.
Also I noticed on the E-Flite site they call for 3 servos without rudder and 4 servos with rudder control so it must use a 2-servo aileron control system. You likely will need a "Y" connector for this.
Good Luck with the "Jug"!!
Ron

Grasshopper
04-02-2006, 06:34 AM
Thanks for the quick reply Ron.

A lot of this electric lingo is Greek to me. If you want to talk glow plugs, pistons and needle valves I'm good to go so bear with me here. Could you please explain what 3S means in Lipos and what 15C means with a 480? Also, what is a balancing plug?

Sorry for all the questions.

Tom

Twmaster
04-02-2006, 06:49 AM
3S means three lipo cells in series. Or 11.1V pack. 15C means a battery that can deliver 15 times it's rated current continuously. As in a 1000mA pack could supply 15,000mA or 15A. The 480 will want to draw a bit more power than a common SP400 setup hence the need for better capacity batteries.

The balance plug is a connection to the battery pack that allows each cell to be individually charged and monitored by the balancing unit connected between the charger and battery. Some of the latest chargers have the balancer built in.

Please don't be afraid to ask away. Great place full of help here.

Might also want to read any of the FAQs and stickies for newbies you can find. Great stuff.

Grasshopper
04-02-2006, 07:07 AM
Thanks Mike,

I've found this forum to be a wealth of information and certainly a great bunch of people that are always helpful and encouraging.

Tom

NotAnAceYet
04-06-2006, 03:04 AM
Tom - I have the E-Flite P-47 - flying it with the stock 480 motor - also installed the landing gear and rudder mod. I'm using a Castle Creations Pixie 20 ESC, and a Thunder Power 3S 2100 lipo. Flies great with that configuration - I get 15-20 minutes per flight with that battery.

Larry

Grasshopper
04-06-2006, 03:44 AM
Hi Larry,
What is the difference between the Castle Creations Pixie 20 ESC and the Sprite 25? What charger do you use for the Lipo? My P-47 arrived today and is sitting in the box out in the shop. Can't wait to tear into it.

Tom

Twmaster
04-06-2006, 03:51 AM
The Sprite does not appear to be Lipo compatible by the specs published on the product description page at CC's web site.

I currently (pun intended :)) use a GP Poly-Charge charger. I -will- be getting the new FMA CellPro charger.

There are many good Lipo chargers out there. It just comes down to personal taste/needs/price.

Grasshopper
04-06-2006, 04:38 AM
This question will probably get a different answer fom everyone that is asked but how many batteries do you typically have for a plane? I have two each for both my PZ J3 and PZ P-51 but it seems like I don't get to fly much and I'm back at the car waiting for them to charge up again. Of course they'e not Lipos which appear to make a big difference.

Twmaster
04-06-2006, 04:45 AM
Most of my planes that have 'dedicated' packs have two packs for each plane. The rest will be flying off a group of lipo batteries that can be shared amongst them. What I usually do is make sure all my packs are charged before leaving to go fly. Use a pack, put it on charge. While charging fly another battery and so on. Not too much downtime for me. If you don't have an adjustable rate charger for those NiMH PZ packs you may want to consider one. I charge my 8 cell NiMH 1000mA packs at 1500-1600mA making my charge time about 35 minutes per pack.

Grasshopper
04-06-2006, 05:05 AM
Hi Mike,
The charger that came with the P-51 will charge up to 10 cells from .5 to 1.8amps. The J3 batteries are 8.4V 600 mAh and the P-51 are 10.8V 1000mAh. I've set the chargers at the recommended settings (.8 amps and 1.4amps) and they normally take about 40 minutes. What do you do to speed up the charge time? Or do you?

redgiki
04-06-2006, 09:38 PM
Here's my usual flight configuration. Of my fleet, four airplanes all use identical batteries that fit perfectly:
ParkZone Stryker
ParkZone Typhoon
E-Flite P-47D
GWS Slow Stick (OK, that one is cheating because just about any battery will fit...)

The battery of choice? A Thunder Power 3S1P 2100mAh narrow form-factor battery. Some vendors sell similar batteries and mark them as working well for the "Trex" or "T-Rex" micro helicopter.

You'll find that this battery and the stock motor result in a plane balanced exactly at the center of gravity without nose weight. With a brushless motor, you end up adding the whole bar of clay to the front to get balance, though.

Anyway, I usually bring four of these LiPos with me to the field. I use the Great Planes Polycharge 4 to charge them in the field. This is a 12V-powered, 4-station LiPo charger that only costs $100.00. It doesn't balance, but I have a stand-alone balancer (The Thunder Power TP-210V) that does that job just fine. Run time with the stock motor on these batteries is around 12-15 minutes, depending on your throttle setting.

At my altitude, though (5000 feet), the stock motor is OK, but kind of a dog. I've called it a 'boat anchor" :) On the other hand, I think the Park 450 I replaced it with is too much motor for this plane; I'm just not sure what I'm going to replace it with yet. I'm guessing the Park 400 is probably a perfect power-match for the aircraft.

As far as ESCs, I like the Electrifly 35A. They are a good size, have an on/off switch, and give you really bright LED status indicators of whether they are set for NiMH/NiCD or 2S or 3S LiPo. Easily programmable without having to use your transmitter: just hold the on/off switch down for 3 seconds. The red light begins to flash. Press the power button briefly to change modes. When the blue light is solid, you're set for NiMH/NiCD. When it's flashing two times, you're set for 2S LiPo, and 3 times your set for 3S. Very easy to understand, and very reliable.

Here's a potential total cost if you bought everything from Tower Hobbies:
Great Planes Polycharge 4 (http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXKAU0&P=ML): $99.99
Great Planes LiPo 2100mAh (http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXMDN3&P=7): $74.99 (times four) (Man, this looks almost identical to the Thunder Power 2100 3S, down to the balance connector... are they rebadging them?)
Some Banana Jack to Dean's Connector charge leads (didn't see on Tower): $5.00 each (times four)
Electrifly 35A brushed ESC (http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXKBF5&P=7): $39.99

Of course, you need servos, receiver, etc. As they aren't power-system related, I'm leaving them out.

Power system cost: $459.94

Holy cow. I suddenly realize why so many people stick with NiMH. I never totalled up how much I'd spent on my electric stuff. Dang! The price of the airplane itself begins to seem trivial...

Well, on the plus side, you can gang these packs together and fly larger stuff, and if (like me) you choose your aircraft based on using the batteries you already have, it's not that horrible.

Anyway, this will keep you in the air almost full-time. In the field, I actually charge my LiPos at 1.5C. Although manufacturers give dire warnings about this, I have nearly 300 flights on one of my cheap LiPo packs doing this, and it's well into its second year of use. High-quality LiPo packs are good for 450 flights or so, so I figure I'm just fine :)

Grasshopper
04-06-2006, 10:02 PM
I've found that you never want to total up what a hobby costs you and secondly, never put it in writing where the wife might see it. This is kind of like when I owned a boat. It's a bad idea to figure out what it costs per hour or how much the fish were per pound. Anyway, this is all good information and I appreciate your help. I'm beginning to think these airplanes are like coffee vendors. They'll give you the machine if you agree to buy the coffee from them.

It's looking pretty consistant on the feedback I'm getting on the system to put in the P-47. As far as the radio, receiver and servos, I have a new Spektrum DX-6 in the mail to me now. I think I got a pretty good deal on it. I paid $166 for it new in the box on E-Bay. Do you find that the off brand Lipos work OK? I've seen several of them on E-Bay for as low as $45 new for a 2100 mAh 3S 15c pack. I just wasn't sure if you could trust them or not and then what charger do they work on?

Tom

redgiki
04-06-2006, 10:46 PM
I've seen several of them on E-Bay for as low as $45 new for a 2100 mAh 3S 15c pack. I just wasn't sure if you could trust them or not and then what charger do they work on?
Any LiPo charger works OK. If you're going to pay $45.00 for that particular battery, I'd recommend buying from a reputable vendor. Dymond RC (http://www.rc-dymond.com/) has been OK for me. The main thing you need to plan on with cheap batteries like this is either you're going to get a 1 in 4 failure rate within the first hundred flights or so, or you need to solder your own balance connector.

I bought six such packs. One of them failed "catastrophically" -- a silver sausage on an outside cell -- in its second season, after about a hundred flights. After that failure, I bought a bunch of Thunder Power balance leads and a TP210V balancer, and manually soldered balance connectors to the rest of my packs. One other one was badly out of balance, but other than the pack running about 95% capacity compared to my others (tracking mAh on my Triton), it seems that there are no other ill effects. I expect that pack to not last as long as the rest, obviously.

So what I'm saying is it's a crap shoot. If you can get one for $45 with a balance connector, the chances are good you can get some reasonable life out of it. Probably not the 450+ cycles you can get with a Kokam, but half the price... half the longevity? That's OK by me :) Really, when it comes to LiPos, "newer is better". I'd take a made-last-month cheap Chinese LiPo over a Kokam made last year any day. The charge and discharge tolerances of LiPos just keep making leaps and bounds changes every season:
2002: 3C peak "red line" discharge
2003: 6C
2004: 7C-10C
2005: 10C-15C
2006: 15C-20C

(I consider the "C" rating to be like red-lining an engine. You stay far, far away from it when sizing your power system, unless you don't mind dramatically reducing the amount of cycles you can get out of your batteries.)

That said, be really careful with cheap LiPos. You get what you pay for, really, and I take lots of extra precautions because I use cheapies. They get charged in a battery bunker (two crock pots), with cinderblocks on top of them while charging. I've extended my balancer leads, and I try to make sure every pack gets 10 minutes of balancer attachment before each flying day. I charge at 1.5C at the field, but I charge at 0.5C with balancer attached at home. I use an auto-detecting charger at the field exclusively so I never worry about improper voltage.

When I move into bigger packs next season to power some .40 and .60-sized glow conversions I'm planning, I am also planning on migrating to FMA Direct Balance Pro stuff. The chief reason is that higher-capacity packs require much higher amperages, and the FMA direct LiPos are rated to charge at 3C. Meaning you get a solid 95% charge in just 20 minutes! My Triton can't put out the amps I'd need to be able to charge two to four 4000mAh packs in parallel at 3c, by a long shot.

comets8518
04-06-2006, 11:22 PM
You really should check out commonsenserc.com He's running his special again.

pay 89.95 for a charger that will charge AND balance you batteries, and select 89.95 in batteries and you get an 89.95 credit. Use the coupon code chargerpromo4

I would try to point you in the direction of my ebay account where I'm selling that stuff, but you really can't beat the deal directly from the site.
www.commonsenserc.com/RC_Groups.htm You can then buy some 3s 2000mah batteries.
the 10c are good for 20amps continous current and 30amp burst current.
the 15c are good for 30amps continous current.
I don't know what the current draw on the p-47 but if a 20amp speed controller would work the 10c batteries will work

Grasshopper
04-07-2006, 12:20 AM
I checked out the web site and it looks like a pretty good deal. For $129, I can get two 2100mAh 3S 15C packs and a balancing charger. If anyone knows of a better place or deal, I'd love to hear about it.

Tom

comets8518
04-07-2006, 12:40 AM
You might consider looking into the amps needed for the p-47 motor. If they're less than or equal 20 you could stand to go with the 10c 2000mah battery and get 3 for 126.
The 15c's will offer you a larger range if you move to other airplanes but the 10c's are also compatible with many others.

And, no you really won't be able to get a charger/balancer, and batteries for less than that, anywhere

redgiki
04-07-2006, 01:10 AM
On the stock motor, with the eflite 10x8E prop, my amp draw was around 12-13 amps, if I recall correctly. YMMV, my static amp draw seems to always be a little bit lower than most others due to my elevation (>5000 feet).

If you buy from commonsenserc.com, the one that will fit the P-47 battery bay without hogging it out is this one:
http://www.commonsenserc.com/product_info.php?cPath=37_25&products_id=39&osCsid=d3b2b0388885ce35450d2a29d7052557

So for $129.95, (he has a two-pack special on these), you'd get two packs and a balancing charger.

Yeah. Can't beat that deal. I'm tempted, and I already have chargers coming out of various orifices!

Grasshopper
04-07-2006, 02:47 AM
I'm convinced!!!! so much so, I just placed the order for the charger and 2 pack 2100mAh 3S 15Cs. All I need now is to get the ESC and I'm good to go. What a deal for a total of $138.91 (that includes the shipping too) you get 2 batteries and the charger. I would have had almost that much in just two batteries anywhere else.

Thanks a lot for the help guys!

Grasshopper
04-07-2006, 05:30 AM
Hey redgiki,

On your P-47, are using 4 servos? I noticed on the Pixie 20P ESC it says it's good for up to 3 servos. Is this for 3 standard size servos and you can run 4 sub micros?

comets8518
04-07-2006, 06:36 AM
I have two each for both my PZ J3 and PZ P-51 but it seems like I don't get to fly much and I'm back at the car waiting for them to charge up again. Of course they'e not Lipos which appear to make a big difference.

to get slightly off topic
I believe your P-51 will run on the lipos you bought (you probably already know that)

But you have to think.. 2100mah (you'll probably get atleast double the flight times you get now) and the 11.1volts will probably make that p-51 a better flyer.
of course you're going to need to show some serious throttle management as to not destroy the brushed motor in the PZ.

Which brings up another point. You might want to look into how to break in the motor on the P-47 so that you get some decent life out of it. Maybe one of the other p-47 owners could help you more on that

redgiki
04-07-2006, 08:30 PM
On your P-47, are using 4 servos?
Yep! One in each wing (of course), the elevator, and a rudder. Fact is, sub-micros don't draw much amperage. I bought a ParkBEC (a separate battery eliminator circuit which would let the servos not drain off the ESC) but haven't used it in this bird. I've run with the cowling off (oh, the howl!) and the ESC is not hot at all coming down after driving.

I probably have at least fifty flights on this bird, and no sign of weakness driving the subs.

If I were doing micro servos, I might only stretch the servo count by one (I believe my E-Flite 20A ESC says it's only supposed to drive 2 servos). On full-size servos, I would definitely forego the ESC's BEC in favor of my ParkBEC.

I'll have to do some servo-travel tests and graph the amps used by my Hitec HS-55s.

redgiki
04-07-2006, 08:33 PM
But you have to think.. 2100mah (you'll probably get atleast double the flight times you get now) and the 11.1volts will probably make that p-51 a better flyer.
Lipos turn the ParkZone P-51 from a fun little warbird into a screaming bundle of excitement. The stock motor handles the volts just fine, and the fact is, it's an $8.00 motor if you burn it out :)

Just be careful. If it starts acting like it's burning out, don't fly it! I blew up a LiPo due to excessive amp draw on a brushed motor. Sucks to have that happen.

Breaking a motor in, particularly large non-ball-bearing motors, is just sound practice for brushed motors.

Grasshopper
04-07-2006, 08:42 PM
How do you go about breaking in the motors? My PZ P-51 and E flight P-47 have not been flown yet. Gonna try to get the P-51 up this weekend. I'm off today and all next week to get some things done around the house. I was hoping to get out today for a little bit but we're having winds gusting up to 30mph. Not ideal for trying a plane out for the first time. Hopefully the weather wil be good next week and I'll sneak out for a while. Also, if I would change to Lipos on the P-51, do I have to change the ESC or anything else? It's totally stock now.

comets8518
04-07-2006, 09:24 PM
http://www.ezonemag.com/pages/faq/index.shtml

why to break in motors http://www.ezonemag.com/pages/faq/a401.shtml

how to http://www.ezonemag.com/pages/faq/a402.shtml

if you search around you'll see more in depth ways to break in motors, such as underwater and other weird stuff.
I personally just stick to the basics.

redgiki
04-08-2006, 02:53 AM
For a brushed, non-ball-bearing motor this size (400-480), my break-in procedure is simple:

* Tape two "D"-sized batteries together end-to-end to create a 2.4V voltage source.
* Tape or solder (I prefer solder, even if temporary) wire leads to your battery. Many come with leads already attached.
* Tape a wire lead to either end of your two D-cells. Whether it's positive or negative doesn't matter; we're going to break this motor in both ways. The leads will probably require quite a bit of electrical tape to get a solid connection.
* The motor will start to run. Immerse it in a cup of distilled water (filtered works fine here, too). Some people say to avoid immersing the capacitors, if already attached. I just drop the whole thing in and tape the leads to the side of the cup. I'd recommend avoiding straight tap water, as I haven't had as good a result with my (very hard) tap water as with distilled or filtered.
* Let it run underwater about 15 minutes to a half hour. Don't run it much longer than that, as a three-hour-long water break-in can also do its share of damage and ruin the motor (don't ask me how I know... it involves a pillowed LiPo...)
* Reverse the motor leads and change out the water (the previous water will be all gray and gucky).
* Run it the other way around the same amount. You'll already have some wear on your brushes, so you won't develop as much gunk on the reverse run.
* Take it out, dry it thoroughly (I use a heat gun), use some 3-in-1 or sewing machine oil on the bushings. I let mine sit overnight to be sure the whole thing is totally dry inside.

I've run motors without breaking them in, and with. For lightly-loaded planes running at low voltage, it doesn't make much of a difference. For planes where I'm overvolting the motor (like a 400/480 motor on an 11.1V LiPo), it's the difference between lasting for many dozens of flights, or lasting maybe 10 before crapping out.

A burned-out brushed motor is a danger to LiPo batteries, too; over-amping the battery can heat it up too much and cause it to pillow out.

In other news, I blew up a second 2100mAh 3S LiPo today. I knew it was going 10 flights ago. It was one of the cheap ones without a balance connector. Though (after soldering on a balance connector) the thing balanced at no load, the cell damage was obvious 3 flights after the battery was new. I've already cut off the shrink-wrap, though, and I'm fairly certain that adding a balance tap to the pack (after seeing the initial damage) voided any warranty I would have had :)

I'm never buying LiPos without a balance connector again! Two packs dead in two years, even though LiPos are cheap that's $90 of $45.00 3S LiPos that I've converted to 2S LiPos. I still haven't found a good use for 2S, 2100mAh LiPos yet in any of my planes. Now that I have two, maybe I'll go 4S and find a small prop for one of my deltas, and turn it into a speed plane...

Twmaster
04-08-2006, 02:58 AM
Yup water break in works great. Just one warning though. Do not do this to motors with replaceable brushes. Only sealed can type motors as they have very hard brushes. Motors with replaceable brushes have too soft a material for the brushes and the water trick will roach them. Also, for completeness sake. Don't do this to brushless motors either! ;)

redgiki
04-08-2006, 03:22 AM
Don't do this to brushless motors either! ;)
Nor to racing-type ball-bearing brushed motors. Although it will break in your brushes nicely, you'll destroy the ball bearings and the motor will last maybe six flights. Use with bushing-types only.

(Don't ask me how I know, please? I learn everything the hard & expensive way, despite reading everybody's advice first!)

The amazing thing about a water break-in is how much longer your motor lasts. I use Johnson J250 motors in some flying wings. On a 2S LiPo, without a water break-in the motors last maybe six flights (or less!) before giving up the ghost. With a water break-in, I've gotten fifty or sixty before burning them out. At $1.50 each, I don't worry about ruining them, but I hate soldering and attaching new motors to my planes. I prefer flying to fixing :)

Twmaster
04-08-2006, 03:24 AM
Nor to racing-type ball-bearing brushed motors. Although it will break in your brushes nicely, you'll destroy the ball bearings and the motor will last maybe six flights. Use with bushing-types only.

Do'h! Forgot that. :/

(Don't ask me how I know, please? I learn everything the hard & expensive way, despite reading everybody's advice first!)

Dude, were we like separated at birth or something? ;)

Grasshopper
04-08-2006, 04:35 AM
So the way I understand this is that I can take the stock 480 motor that came with my E-Flight P-47, connect two D cell batteries in series, connect it to the motor leads and drop it in distilled water for 15 to 30 minutes? Again, I'm new to this electric stuff and if anyone would have told me before I joined this forum to do this, I would have thought they were insane. Motors, electricity and water? Not that 3 volts is going to knock your socks off but the thought of dropping a motor in water and running it....well.......

so can I do the same for my PZ P-51 motor?

redgiki
04-08-2006, 07:36 AM
connect two D cell batteries in series...

Note that D-cells aren't strictly necessary. AAA, AA, C, and D work equally well. I chose D because that's what I had lying around my house. They also have over 9,000mAh per battery. The pair I've been using have been used for, well, a bunch of brushed motor break-ins :)

I choose to run it at 2.4V (2 cells in series) rather than 1.2V as some recommend mainly for speed reasons. 2.4V still doesn't arc on most motors, and gets the break-in finished in maybe 15-30 minutes, rather than 2-3 hours. I've had bad luck with motors that had a break-in run that long; I figure if the brushes aren't seated in 15-30 minutes at 2.4V, then it was probably a bum motor anyway. My measure of "have the brushes seated" is "is there gray gook floating in the water yet?"

so can I do the same for my PZ P-51 motor?
If you've already flown it, a new "break in" won't do anything. The purpose of breaking in a motor is so that the brushes seat evenly on the commutator, and so that the residue of this seating isn't left in bad places (like between your bushing and your shaft).

The goal is to reduce wear on the motor, and to forestall some of the arcing that happens at high amps.

If you've already flown your motor, you've already "broken it in"... it's just that the way you broke it in probably scarred your commutator due to arcing, wore the brushes unevenly, and put hunks of brush-dust in uncomfortable places. Fly the motor until it dies. Once it does, go drop $10 at the hobby store, buy a new one, and break it in properly.

I haven't seen any difference in the power level of broken-in vs. not-broken-in motors. Just longevity. The less time I spend fixing things at my workbench, the more time I have to fly!

Just be aware of how much power you're getting out of a motor whenever you fly brushed. There's a good chance that if your power seems to sag, it's probably because your bushing has worn out. This condition will destroy LiPos if you fly too long, because the amp draw is so high. It's wise to bench-test your aircraft for a short-duration run (like 30 seconds) to watch what happens to the voltage. Do this when the motor and battery are new. Use that as your baseline. If your voltage is way lower during a pre-flight check, the chances are good your amp draw is too high, and it may be worthwhile to tear things apart to get an amp reading.

I understand there are supposed to be some meters which can measure amp draw now without requiring to be placed in series in your power path, but I haven't bought one yet.

I usually do my voltage check the night before a flying day, if it's not a "daily driver" aircraft that I fly so often that any small power change is noticeable. I'm gradually replacing my brushed motor collection with brushless, though, and overall brushless seems to be much better for battery and motor longevity. Once again, less bench time == more flight time :)

redgiki
04-08-2006, 08:05 AM
Dude, were we like separated at birth or something? ;)
I've found that, within the R/C aircraft community, there seem to be a lot of us with thick skulls and thin wallets.

For instance, I received advice that I should seek out an instructor, join a club, and then begin flying. I received this advice about two weeks AFTER I tried to fly the first time! I took my new ParkZone J-3 cub to a local park (which was much too small, and with trees much to large, for me to consider flying in now), threw it in the air, and expected to fly like a pro.

You can just bet how that turned out :)

I rebuilt that Cub three times.

I'm now a member of a club, had some instruction time, and spend a good deal of time on a simulator when I'm not out flying the real thing.

Same story on motors. It takes so long to glean useful information from these kinds of threads, that I end up glossing over things. Some advice is junk, and some is worthwhile. It takes expensive mistakes to learn which is which.

As another "ferinstance", LiPo batteries. I've actually destroyed four of them! One in a crash. Two due to brushed motor over-amperages (exacerbated by being out of balance, I think). Another one seems as if it was probably defective from the factory.

The expensive lessons learned?

* Size your LiPo appropriately. Budget lots of spare "C" to cover up to twice your expected amp load. One of my blown LiPos was being run right at capacity limit: a 6C 1300mAh LiPo being run up to around 6-8 volts when things were "normal". Well, 6C * 1.3A = 7.8 amps. There was no room for error, and when the motor bushing wore out, the amp load went through the roof. I should have either put another pack in parallel, or used a different brand of battery than the cheap GWS 6C crap LiPos. They were cheap though! Learned my lesson when that one came down smoldering.

* Find a way to put lots of padding or other "slow down, honey!" method between the battery and potential impact points. Give it a "soft out". Sure, you want to build your planes to fly, not crash, but a good design will save your battery. One thing I did recently when I rebuilt a Stryker was to hog out a bulkhead, and line the sides of the battery compartment with Velcro. The battery itself received some opposing Velcro. Well, I dorked that one in due to servo failure, and despite going in hard, there was no battery damage. The battery had slid forward, catching on all the velcro, right up to the nose of the aircraft.

* Measure and write down your measurements. Use them to compare later. If you don't have a baseline when the item is new, it's tough to know when something's going wrong.

* A voltmeter is your friend. Use it all the time, even on your NiMH and NiCD stuff. It will alert you to potentially dangerous problems. Like if I'd paid attention to the fact my charger was shoving 48 volts into my NiCD receiver pack, I'd have realized there was a dead battery under that shrinkwrap, and not had that explosion in the garage! It made me glad for my battery bunker that day. NiCD and NiMH are just as volatile as LiPo. They just take more abuse before they explode.

(Note: this was a Triton charger. I'd had some problems with this pack, and was trying to do a charge/discharge cycle to troubleshoot it. The pack immediately prior to it, which I'd bought at a yard sale, recovered just fine and was able to hold full capacity within 4 cycles despite not being used for 5 years. This pack, however, didn't... when I looked at the battery after the explosion, it had leaked long since and had gone all crusty, crystalline, and rusty.)

* ebay is only your friend if you know exactly what you're doing, and exactly how much what you're trying to buy or sell is worth. (Hint: That "vintage" aircraft kit may be another word for "messed up"...)

* Don't buy items on eBay listed from people who live where there was recently a major natural disaster. (Hurricane Katrina, bought a Futaba flight pack... that's a tale for another time.)

* Learn who knows what they are talking about at your local hobby shop. Find out when they work. Only shop at those times. ("All our CA glues are foam-safe" my perky pink posterior!)

* When the GWS receiver says the range is 400 feet... they mean it! Don't believe what the forum-ites tell you on that. (One crashed and smooshy LiPo, coming right up!)

* Double conversion receivers really are better than single-conversion ones. I don't care that you can theoretically make a single-conversion that's just as good as a double. That doesn't mesh with reality. If you're not going to be the only one flying... go double. (Shot down in a blaze of glory by a guy turning on his transmitter 2 channels away while I was out really far away from my Tx...) Or else plan on flying very close to yourself, all the time.

* Don't pick your nose or rub your eyes while working with CA. Really, don't ask me about that one.

* You should wear surgical gloves while working with high-strength glues.

* You should remove said surgical gloves before attempting to urinate.

Oh, there are so many more!

Crap. I've really gone off-topic. Sorry about that.

Back to the E-Flite P-47! Got a few more flights on it today; we were at the field for nearly four hours. Good stuff. Blazing fast downwind runs. Life is maintenance-free on that bird now that I don't have those stupid wing covers on anymore.

Grasshopper
04-08-2006, 02:52 PM
The PZ-P51 has not been flown yet so I can still break in the motor properly. It looks like I have to cut the decals to get the cowl off. Since I'm somewhat of a perfectionist, I'm sure I'll cry but I"ll do it in private and get over it.

Here's my set up for the P-47: Stock 480 (broken in) motor. Spektrum DX-6 system. I'm going to start with ailerons and elevator only and no landing gear or bombs. I'll be using a Castle Creations 20P ESC and CommonsenceRC 3S 2100mAh 15C Lipos.

See any issues here? I feel like I'm researching this thing to death but the last thing I want is one 5 second flight out of it.

Also, on using packing tape for reinforcements, do they make a tape with a flat finish? I just cringe every time I think of putting that shiney stuff on my warbirds.

Sky Sharkster
04-09-2006, 01:15 AM
Hi Tom, looks like you're getting plenty of good advice here. For break-in, I use two "D" cells also, run underwater about 15 minutes or until the water is solid gray (light gray). Only difference is I run it exclusively in the direction it's going to run, not both directions: Probably not a big deal. Then dry it with a heat gun or hair dryer (hold by the prop shaft with pliers) and oil front and rear bushings. Radio Shack sells a plastic holder for 2 "D"s that has short wires attached, ending in two alligator clips. Perfect! Costs about 4$.
Your setup sounds pretty good, double check the amount of throw (deflection) of the control surfaces, don't use more than recommended. The single biggest problem for new flyers is overcontrol. Second biggest problem is "Reversal", that is, when the plane turns from going away from the pilot, to coming towards the pilot. Now left is right and vice versa. "Up" is always "Up" though, until you fly inverted!
For the "shine" on the tape, try steel wool, very fine grade. This also will break the "gloss" on iron-on covering. It won't quite be "flat" but it won't make you wear sunglasses either.
Good Luck!
Ron

Grasshopper
04-09-2006, 02:32 AM
Thanks Ron,

I'm getting ready to break in the motor this evening. I've been over the P-51 probably ten times to check everything. I think I'm going to wear the thing out before it gets in the air. As far as getting used to the controls, I've been flying a PZ J3 for the last few months to get back into the swing of things. I used to fly .40 and .60 size sport planes a few years back and it seems to have come back pretty well. The J3 probably has close to 50 flights on it now with no problems. I've gotten to where I can do loops, stalls and touch and goes with no problem so I think it's time to progress. The weather is suposed to be really nice tomorrow with light and variable winds. I've been putting off the P-51 maiden until I had a really calm day.

If it even looks questionable, she'll stay in the car.

Twmaster
04-09-2006, 02:33 AM
Best of luck Grasshoppah!

Grasshopper
04-09-2006, 04:15 AM
Aahhh thanks Massa!

comets8518
04-09-2006, 05:27 PM
I think you have a great set up to.

Just double check your Center of Gravity (I'm sure you already know this).
When maidening my Formosa about 2 weeks ago, my Cog known to be off by about 3-5mm and I think something slid upon the take off..and well the plane had a magnet for the ground or something. It broke into about 20 pieces, snapped my prop shaft in half, etc etc. It looked like a lost cause to fix but it turned out to be super easy.
Like you I come from flying .4 and .6 planes a while ago, so I thought it could be my flying ability.

Long pointless story short. I fixed the plane, added some tail weight and remaidened yesterday, it flew great and was a lot of fun.
I was even surprised how well the plane slowed for landing

-moral: Check your CoG, If your plane does crash within 5 seconds pick everything up, go home (or hte field if you got time and/or CA and start putting the puzzle back together and keep at it.

good luck and take videos.

My crash maiden is listed here http://media.putfile.com/mosa-crash (adults only as my peanut gallery couldn't hold back after seeing the crash)

redgiki
04-09-2006, 09:50 PM
I've been putting off the P-51 maiden until I had a really calm day.

If it even looks questionable, she'll stay in the car.
The terrifying thing about the ParkZone P-51 is that the maiden has to be a hand-toss. And usually, you'll want someone else to throw it, and they'll screw it up, throwing upward at an angle rather than flat, or sideways or something.

Good luck :) I love maiden flights. I think that's part of the reason I have so many planes now... after the successful maiden, how do you top that?

Be ready for the P-51 to torque left if you launch full-throttle. I find the torque roll less scary than not having enough power going on the toss, though, so I always do full-throttle tosses and am just ready for the roll.

redgiki
04-11-2006, 03:58 AM
One other one was badly out of balance, but other than the pack running about 95% capacity compared to my others (tracking mAh on my Triton), it seems that there are no other ill effects. I expect that pack to not last as long as the rest, obviously.
Just so y'all know, that "questionable" pack lasted exactly two more flight safter I wrote this. I flew its last flight in my E-Flite P-47, during a four-hour flying session. As I was concerned about the pack, I charged it for its second flight at 0.5C in the field, with balancer attached. It was badly out of balance after its first flight of the day. During the second flight, the third cell sausaged on me, and I'm now the proud owner of TWO 2S 2100mAh packs, converted from 3S.

(This is the pack that started showing problems 3 flights after purchasing it.)

I'm just glad it's not a total loss of the pack. Now like the GWS packs I bought. Those little 2S 1300mAh packs burned out within fifty flights each. They were only $25.00 each... and I got what I paid for, I guess.

The moral of the story? Be cautious with buying cheap LiPo packs to power your P-47D. At the very least, particularly if they are cheap packs, they must have a balance connector so that you can continue to gauge their health over time. With this pack today, had I not been aware that it was having a balance problem, I might have glibly field-charged it at full amps like my other packs.

Out of the three 2100mAh packs I have left, two have about twenty-five flights each, and one is left over from last season, happily puttering away at 98% capacity with well over a hundred flights on it. It was my only LiPo pack for much of last summer, and was used 2-3 times a day for weeks on end while the weather held.

I think I'll buy four more 2100s from commonsenserc.com. I have a hotliner that a pair of these would power perfectly! It will be interesting to see how they compare to the marginal-quality LiPos I bought from rc-dymond.com. Of course, the more packs I own, the less each pack gets flown! Kind of an odd catch-22 there. Maybe I ought to move up to 3S3P to be able to use all the packs regularly...

ragbag
05-06-2006, 03:04 AM
For a brushed, non-ball-bearing motor this size (400-480), my break-in procedure is simple:

* Tape two "D"-sized batteries together end-to-end to create a 2.4V voltage source.
* Tape or solder (I prefer solder, even if temporary) wire leads to your battery. Many come with leads already attached.
* Tape a wire lead to either end of your two D-cells. Whether it's positive or negative doesn't matter; we're going to break this motor in both ways. The leads will probably require quite a bit of electrical tape to get a solid connection.
* The motor will start to run. Immerse it in a cup of distilled water (filtered works fine here, too). Some people say to avoid immersing the capacitors, if already attached. I just drop the whole thing in and tape the leads to the side of the cup. I'd recommend avoiding straight tap water, as I haven't had as good a result with my (very hard) tap water as with distilled or filtered.
* Let it run underwater about 15 minutes to a half hour. Don't run it much longer than that, as a three-hour-long water break-in can also do its share of damage and ruin the motor (don't ask me how I know... it involves a pillowed LiPo...)
* Reverse the motor leads and change out the water (the previous water will be all gray and gucky).
* Run it the other way around the same amount. You'll already have some wear on your brushes, so you won't develop as much gunk on the reverse run.
* Take it out, dry it thoroughly (I use a heat gun), use some 3-in-1 or sewing machine oil on the bushings. I let mine sit overnight to be sure the whole thing is totally dry inside.

I've run motors without breaking them in, and with. For lightly-loaded planes running at low voltage, it doesn't make much of a difference. For planes where I'm overvolting the motor (like a 400/480 motor on an 11.1V LiPo), it's the difference between lasting for many dozens of flights, or lasting maybe 10 before crapping out.

A burned-out brushed motor is a danger to LiPo batteries, too; over-amping the battery can heat it up too much and cause it to pillow out.

In other news, I blew up a second 2100mAh 3S LiPo today. I knew it was going 10 flights ago. It was one of the cheap ones without a balance connector. Though (after soldering on a balance connector) the thing balanced at no load, the cell damage was obvious 3 flights after the battery was new. I've already cut off the shrink-wrap, though, and I'm fairly certain that adding a balance tap to the pack (after seeing the initial damage) voided any warranty I would have had :)

I'm never buying LiPos without a balance connector again! Two packs dead in two years, even though LiPos are cheap that's $90 of $45.00 3S LiPos that I've converted to 2S LiPos. I still haven't found a good use for 2S, 2100mAh LiPos yet in any of my planes. Now that I have two, maybe I'll go 4S and find a small prop for one of my deltas, and turn it into a speed plane...


I haen't read the whole threadword for word, so I will start with the first post. Not picking an anyone person just noted one thing. Distilled water is a waste, any tap water will do. Distilled water is an insulator and you are waiting for the impurities to get in the water to start the polishing process.

Now as I have said I might be repeating something already said.
I have a pc power supply that I threw a 5 volt tap out of and that is what I run the breakin with.. Alligator clips with work for the break in, no solder, some motors come with internal capacitors, break it in as usual, you cant/shouldn't open the can to get to them anyway. I fill the beaker with tap water and hold the motor, put the power to her.

When the water turns a litle gray I repplace the water and start again, maybe three times each time the water is cleaner. I have seldem run them more than three times 5/8 minutes to a run. The only one that laste for several runs Sig replaced right away. Good People.

When I was racing RC boats the Hitac factoy rep put me on the alcohol trick.

After I run it in I drop it in a container of alcohol for a few minutes, per their instructions, works great on all their servos except the big expesive 700"s:( .
They have SMT controls and they are dead as soon as he voltage is connected.


Blow out with compressor and lube. Run for a few minutes to remove the alcohol. Bearing and all. Water doesnt get in the sealed bearing.

I do remove the gear box for all this and never run the motor in the opposite direction of the intended use. EDIT(( the gears got my finger one time)))
To reverse it you have now chipped the leading edge ot the brush and wasted all the good work that you have just done.

Many years ago we did slot cars and disassemble the little Mabuchi can motors and trimmed the edges of the brushes and the reassemble them and hand turned them to polish the commutator, dissassembled it and cleaned the commutator with a tooth brush before we ran the motor. Used tooth paste to polish the gears for breakin.
Hand soldered brass frames.
Boca bearings on all axles.
I loved the five window coups.
Some of the guys nickle plated thier frames, coud never get that to work for me.:(




.

redgiki
05-08-2006, 07:55 AM
...no solder...

Looking back at it, I realize that I misstated myself. I solder leads onto the motor, not onto the battery. I think I want to set up some leads to run it off the 5V circuit on my converted PC power supply and speed the process up some, if I ever buy a brushed motor again...

flydiver
07-20-2007, 06:04 PM
If you've already flown it, a new "break in" won't do anything. The purpose of breaking in a motor is so that the brushes seat evenly on the commutator, and so that the residue of this seating isn't left in bad places (like between your bushing and your shaft).


FWIW I had a Super Cub 480 that was "missing". It had lots of flights on it. Having nothing to lose and having just learned that water break in was a viable option I tried it. The missing went away. Been flying that same motor for months. With that unit I can see the brushes so know if they are worn out and they aren't (yet).

fly

Ryan Flyer
06-29-2009, 06:35 PM
I will have to try this.
Ryan