Hi,
I am new to electric and have realised that there is a lot more to it than I thought.
I have a PC9..Winspan 955mm..length 715mm. I have put a Himark 2000 brushless in it with a Phoenix-25amp brushless sensorless speed control.
It came with a cobalt 400 motor and a 1200mah 7 cell nicad pack.This pack weights 9.5oz (270gr) I felt that I could go a little lighter. With the new motor etc I would like some help in battery choice for the set up.

Kindest Reagrds
Chris

maybe lipo but in the down under i dont know availability or price.kokam or thunderpower in the 2000 mah range should still weigh less than your current pack.2s for 7.4v 3s for 11.1v.look for other forums containing li-polly info,or maybe some nimh.lipo`s are pricy at first but pay off in the long run when used properly.lipo`s have stringent guidelines that must be followed but when you get it down you wont be let down.nihm batteries cost less and are more durable and forgiving than lipo with nicad being the toughests but heavy.good luck

The bulk of the membership on RCU may not be familiar with this "Himark 2000" motor. I know I haven't heard of it, and I can't find any useful reference to it with Google. Can you post a link to it?

Without any specifications, there's no way to know what battery and prop will work, or if the motor is even suitable for your application.

What was your reasoning behind choosing this motor?

Hi Mate,
Thanks for your reply.
The motor in question was purchased after I talked to the local model shop.I know cobalt motors are greedy.So I decided to give the brushless a try and to cut weight.
I have a watt meter ordered.I am trying to understand lipo's and all that goes with electric flight, it is very involved if you want to do it right.I will try to find a link.
Thanks again

Regards
Chris

Hi Mate,
Thanks for the reply.
Before doing anything with the PC9 I will learn more about electrics.
I have used lipo's, they are great and yes care must be taken at all times with them.
Thanks for your assist.
Regards
Chris

Hi Chris

Just found this thread, having done exactly the same thing with my PC-9 (Himark brushless + Phoenix 25 + 1800mAh Lipo pack).

I am also a beginner to electric flying, though I do have some electrical background.

Plane flies pretty good, however ESC trips if I try and run full throttle on a 7 X 4 prop. Just invested in a (DC amp capable) clamp meter which tells me it's tripping at about 18 Amps. No info on max discharge rate for Lipos (There is some writing in Chinese or Japanese characters on the pack though) however I assume that I am exceeding. Have set the Phoenix to cut at 9v to protect the Lipos.

Going to try propping down a little to try and reduce the current draw, am also looking at setting the throttle travel on my Tx.

How are you going with yours?

Regards


Terry

Prop down. Don't bother with limiting the throttle travel.

Most ESCs reset the throttle travel each time they're powered up. You would have to reset your throttle to 100%, then power up the plane, then reset the throttle back down. Royal pain-in-the-tuckus.

Limiting throttle travel is also not a real solution. The Amp draw you're seeing on the meter is an AVERAGE. From moment to moment, the battery is seeing small full-current pulses, because the ESC is just a fancy on-off switch. Those full-current pulses are being handled by the ESC and motor. If your full-throttle current exceeds the limits of the motor or ESC, you can rest assured that the limits are still being exceeded at partial throttle.

The best solution to drawing too much current is to adjust prop size down until the current is within the limits.

Hi Terry,

I have had over a period of time so many given ideas and suggestions from others (all good intentioned) that I was starting to get lost with electrics.This forum has helped me to get my mind around it.

I found that the Whatt meter advanced my knowledge greatly.

I'm putting together a booklet of all the usable Q/A (elec) on the forum, this is a handy reference and allows me to solve any questions.

Kindest Regards

Chris

Hi Chris,

Did you get the PC-9 flying yet?

Very happy with the way mine flies, gonna try a 6 X 4 prop instead of the 7 X 4 when I can get one.

Regards


Terry

not yet mate.............getting a couple of gliders ready to launch of the cliffs.

Chris

Go lighter is good cept that the c of g is affected. I have the same acft, motor and speedy. I tried a Kokam LiPo 1500 and 2000 and the thing went like a caned cat but the balance was all wrong. I now run 2 x Kokam 1500's. Squeezed right up against the front bulkhead. I am using a 6.5x4 graupner scale prop. The thing howls. You want vertical performance you will have it with this set-up. Weight is not so much of a problem when u have horsepower. Appch speed is a little higher but................ Be careful with control surface throws too. It is VERY sensitive. If you do go the Lipos just make sure the cutoff is set from the default 5v to 7.6v (I think) for 3 x LiPo cells. [>:] Let me know How you go.

G'day again Chris 44
P.S. I say that about the cut off coz I fried the 2000mha pack . Middle cell cooked.
The new set of 1500's (using a "Y" lead. I also replaced the std LiPo wire and plug with more robust wire and deans type plugs) I separated, and placed two paddle pop sticks between each cell to allow just a little air flow.
I have them sitting side by side on the end of the plate in the fuz ,with a gap between each pack motor wires hold them apart.
Make sure you cut the ends off the four screws holding the nose wheel on (replaced with a bit of lexan, a fast landing tore the standard plate off). These may pierce the LiPo pack (not good).
The slow speed performance is not too bad either with the wing not prone to violently tip stalling.
Use a dremel to cut through the cowl at the dummy exhaust stacks to allow air in/out.
If I have any more heat problems I expect to put in a couple of vent in the fuz. Enjoy ..... I am having a ball.

Berger58
Brisbane

i got me a himark 2000 with 15 amp speedy for my extrafun, i have the same pc9 too but thought it was heavy as well, its under the bed somewhere now........... thge extra fun is heaps lighter and esayer to fix and replace, i just finished installing it all with a 7x5 prop, the guy reckons she'll hover, i hope so

let me know what u think, i have no idea about amps and stuff i just ask alot of questions, i think the guy in my hobby shop likes me when i hold my wallet more than when i dont, its a helpfull hint for asking heaps of questions and getting happy answers, we all know hobby shops DONT LIKE US YOUNG FOlKS, unless your waving cash.

let me know