I checked the ESC this AM. It is a 45A from a company called Castle. Does this change anything? Can I safely put a few flights on the bird?

David

From the other guys posts a Castle Creations 45a esc shouldbe able to take the load. Your batteries may still be the downfall. And it is your plane, give it a quick flight, say 2 minutes, then check you batteries. Are they warm? If so, you still are over propped. It wouldn't hurt to cycle the batteries a couple of times as well.

Tim

Dave, your good to go with that Castle 45a esc... nice reputable item you've got.

Now you need to know if your pack is going to get hot (without the aid of a meter).
Try this...
After clipping the prop down, just give it all a 1-2 minute steady 1/2 throttle static run while tied to a chair or something.
It wont have any air being rammed into the cowl like it would in flight for cooling, only the prop-wash, which by comparison isnt much.
So if your leads are long enough, keep the pack out in the open, lay it on the floor in the prop-wash area.
This will enable you to touch the pack and check its temp during the test... slightly warm at 1/2 throttle under these conditions is ok.
Even if the pack stays cool, (it should), avoid the temptation of running it harder except for very short bursts... you dont want to get the motor too hot, which is easy to do while static testing. My 2818 will get noticably warm/hot while checking amps/watts with a meter, but if I check it right after a hard flight its always nice and cool, the pack is simply warm. It's all about air flow.

I will give that a try on Sunday. The motor does have air scoops on the side of the motor box to aid in cooling. It should be OK. I have also closed off part of the cowl as recommended by E-flight.
I was also thinking about the + & - on the Deans conecters. I soldered the ESC first and those wires are color coded. I should be OK on that. The landing gear shipped on wed. It might come today so i can fly it Sunday. Inless the 4th holiday slowed it down. At least I can strap it down and do the battery test.

Thanks again for all the help.
David

I ran two 3 minute test this AM. One before the prop was cut down and one after. Both times the motor was slightly above room temp. The battery however was warm both times. If there was any diference in batt temp between the two test I could not tell it. I could easily hold it on my hand but it was warm.
So what prop do I need? 13x6E or 13.5x6E? I am open to suggestions.

David

Ack.. While thinking about a good prop for you I went and did a bit more reading on your specific plane and the combo's EF sells... and got conflicting info there vs their motor specs/prop recommendations on the motors page.
They recommend a 14x7 on the Yak page, and on the motor page they top at 13x6.5... humm..

Now I suppose I'd "try" a 14x7E for all around flying and hovering/3d as they recommend with your same lipo.
That sure seems like a lot of prop though... and I wouldnt expect much for flight times on a 2170 pack.
For sure, I'd keep a close eye on pack temps with that prop.

I'd pick up a 13x6.5E and 13x8 for good run times/cooler packs.
I'd also grab a 12x10 for higher speed aerobatics (and plain ol' curiosity).

It's kinda hard to get a grip on what will work well and keep your packs in good shape with their odd info and my experience with the 900kv motor (2818).
I wouldnt put any of those props on my 2818 (except the 13x6.5), which is only 80kv more than your 2814.
They've made a 1" length and .5 pitch jump up with a mere 80kv (rpm) drop on the motor... it doesnt really add up based on what I see with my setup.
All of my 2500 25c's come down sorta, but comfortably, warm after turning a 2818-900kv motor with a 13x6.5E on a fairly slippery 3dhs Katana after 6-7 minutes of hard'ish flying.

In the end I would probably run the 13x8 for good flight times, respectable power, and pack life.

Thank you for the help first off. Now if I can bother you with a few more questions.....

If proped right, how much flight time should I be getting? Do the battery packs get warm even with the right set up? I mentioned before my charger takes an hour per pack. I understand this to be normal now. However my charger has no way to discharge the packs. It is only a field charger. Do I need something that will cycle them?

Thanks Again, David

I set my Tx's timer at 6 minutes for all of my electric planes and land before 7 minutes even when there is plently left - avoid bottoming a pack out, it hurts them.
You should get that 6 minutes too if its proped for max performance (14x7) and your packs should be warm+, or very slightly toasty, if that makes any sense.
It should not be hot or puffing. You should certainly be able to hold it (gripped) without a hot-potato sensation - it shouldnt hurt you.
I guess, without ever having taken a temp, a 6 minute pack should be around 120F, plus or minus a bit.

With a 13x8 you'll find better run times and cooler packs compared to the 14x7.
Maybe 7-8 minutes and barely warm packs.

No... do not "cycle" or discharge these packs (I have not found a use for it anyway).
In fact, if you run your packs too low a few things happen:
- Your esc will enter LVC (Low Voltage Cutoff) and at best, it will cut your already-dying power in half = cant maintain flight and crash.
- Your pack is likely to get hot.
- Your pack is likely to be damaged/life shortened.

Land with plenty left in the packs, let them cool a bit, and recharge from there. Lipo's dont have a "memory" of sorts.
My packs normally check at 10.8 to 11.3 volts after 6 minutes - a good range to be in with reserve saved for a go-around if need be.

Thanks again for the info. I think I have a little better understanding now. I would have estimated the pack temp in the range you said. For now I think a will use the prop I cut down. Next time I'm in OKC I will pick up a 13x8 and give it a try. It sounds funny to me to use a 8" pitch prop to 3D but I know the elec motor is a different animal compared to a Saito.

Thanks Again, David

Your welcome Dave.
Question... why would you drive 100 miles when the on-line stores are a quick click away... let the postal people burn their gas?
I'm all for keeping the LHS alive, but sheesh, thats quite haul for you.

Your right of course. But then I would not get to eat Chilli's and go to the hobby shop. If I get in a bind for something I will mail order it. Also the LHS does a lot to support our club. He or his son have been to every one of our 19 annual fly-ins,among other things.

David

Ok Ok... go get your $100 fajita's and prop's...

I did find a couple of threads you will find interesting... (The first one is directed at your Yak)
http://www.rcgroups.com/forums/showthread.php?t=579706 (maybe you found this already?)

The second talks alot about your motor, packs and prop selection.. read up... maybe a 14x7 is really the way to go with your 3 cell packs?
Anyway... here is some good info...
http://www.rcgroups.com/forums/showthread.php?t=835764

Take note of the 4 cell info in that thread too... especially if your power-hungry.
They talk a lot about running 4cell packs with your motor... well, a bit of quick reading at CastleCreations.com leads me to think you have the 45amp "Pheonix" esc, which will also run 4cell packs. (There is no 45amp "Thunderbird" 3cell version listed)
Hell, even your Equinox balancer will take care of up to 5 cell packs.
Your motor, with a 12x8 apc prop, on a 4cell 2170 pack will put out a whopping 500 watts at 40amps - huge power for your plane.
In the end your pretty much all set for 4 cell - just make sure your field charger will handle 4 cells.
(If it doesnt, goto Fmcdirect and get a Cellpro 4s - excellent balance charger - I even bought 2 of them)
All you need is the packs, the bec and maybe a charger.
Keep in mind, the electric motor and esc, just like glow power... will outlive almost any plane you put it on.
So upgrading for more power is easy, now or during your next build.
As for getting 4 cell packs, go to hobby city.com and check out their Zippy 2000mha 4s1p packs... I have a bunch of their packs and like them alot - great power, half the cost, just buy enough to make shipping worthwhile.
(The hobby and city are together... I get **** anytime those two words are mated in this forum... go figure)

Fajitas? Have you not tried the Big Mouth Bites?

Thanks for the links. Time restraints make this the only forum I visit. I will read the ones you sent when I get the time. Work is crazy right now. Straight line winds took 200sq ft off of our roof 5 weeks ago. Then it rained 4". I manage a furniture store. We lost 26,000 sq ft of furniture in our warehouse. It sat in 3" of water while we pushed water out as fast as we could. Still cleaning and waiting on insurance company to get it in gear. This hobby is the only thing keeping me sane.

Thanks again, david

Dave ... 4S is the way to go for this baby ... once you tried it there is no looking back. The power to weight ratio is amazing for the given wing loading when it comes to EP.

I finally put two more flight on it today. The 4S may be something to look at down the road. Right now I have no complaints about the performance. It is taking a little getting use to it. Mostly, I think, because the plane is so light. For example I did a rolling circle at about 1/3 throttle today. In a glow plane I would use 1/3 power all the way. This plane started to slow as I deflected the surfaces. The extra drag on a 3lb plane required more power. Same on a snap. The plane was pretty much stopped after the snap. Not that this is the fault of electric. I really just think it is the overall weight.
I did not run the 14" prop today. I only ran the one I cut down to 13". I will try the 14" next time out. It would be hard to beat the performance I got today but you never know.

David

No... they dont carry much inertia.
Glad your liking it.
Yea, go get that 14x7E, it looks like the prop to go with.

I am glad to see so much good helpful commentary in this forum!
Good to see you come to the Dark Side there dave..
if you go to 4S you Cannot use the same prop..you will have to go down in diameter and pitch or youll have a smoker!!
the more cells the less prop! never forget it..

I noticed on the Extreme site the more cells less prop thing. For now I am going to stick with the setup I have and learn as much as I can about it. I will be the first to admit all this electric stuff baffles me. So I figure the less variables I have right now the better off I am. Down the road I can start tinkering with different batteries and motors and ESC's. Plus I need 15-20 flight to really get a strong feel for a new plane.

David

Dave ... you been an IC engine person all this time, tell us your first impressions of EP. In terms of how the plane feels with electric power.

Dave on your next Deans adventure just remember that however you hook up black and red do the same on what your plugging into. I have alot of Deans plugs on things and it does not matter which side the hot wire is on as long as the one your plugging into is the same way. I have also never noticed a + or - on them. Good deal lucille glad your liking it. I wish I could change all my planes to ELEC, but the batteries would be mucho $$$$$ probabaly in the long run might even out but that would take alot of fuel burnt. Now fuel may get hard to purchase though.
Oh i only have a few batteries and they all work on all different planes so I guess I am lucky that i got them all the same lol.

What part of it are you trying to get your head around? Ask away...

tIANci, Elec vs. glow is hard to read right now. I just don't have enough time on the elec. I have a few glow planes with power to weight equal if not better then this elec. I have noticed in a hover the throttle needs less work on the elec. I find myself working the throttle on the Saito and setting and forgeting on the elec. With only three flight on the elec most of the differences I have noticed are on the flight line. I can see were the ease of assembly is much easier. Also the amount of stuff taken to the field is about half. Not to mention at the end of the session your done. No cleaning, no burning the fuel out, no after run, no mess and smell on your hands. All these things are a big plus.

Dashunde, you have been a great help and I know you will be in the future. When I say this stuff baffles me I think it's the little stuff. I have been flying glow for 20 years. (this may sound like bragging,sorry) But I am the guy in the club that people look too when they can't tune their engine or wonder what prop would work best with this combo or cant get their plane to do this manuver etc..etc.. I also do 95% of the test flights in our club. So for me to know sh*t about the props,ESC and motors is a little tough for me to swallow at times. For example on the balancer I got to charge the batteries. I tried to read and understand the book. I have read it twice and still don't follow the logic. I can make it charge the battery packs but it will do so much more and I cant run it. When I get time I am going to bring it in the house and ask you a few questions. For now it charges and I am content with that. I think being dislexic and having a LD is coming back to bite me in the a**.

David

Dave ... soon you can try some really over powered small EP planes, they are fun. I do enjoy not having to clean up etc but then it comes at a cost. Enjoy your EP plane!

Is that because if you have higher volts, then the motor must be allowed to burn through the higher volts by spinning faster? So like, if you go up in cell count (and volts) without changing down from the larger prop, then the motor can't spin faster with the over-sized prop and the extra volts then go to maker the motor hotter?

I'm trying out electric soon too. This is a really informative thread.

Cheers

we cloud skipper you are basically correct.

increase in voltage means increase in rpm, the increase in heat. The motor needs to allow the heat to dissapate by spinning more RMP. If the prop will not let the motor unload then the heat created just stays in the motor and melts the varnish off the windings and the motor shorts out.