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Old Mar 07, 2006, 11:56 AM
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elfwreck's Avatar
United States, CA, Oakland
Joined Dec 2002
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Quote:
Originally Posted by Jurgen Heilig
The difference between having to waist 2.5W and 6.25W enormous (250% more to be precise ) and many small ESCs won't be capable dissipating the resulting heat without direct air cooling.

No point in having a more efficient motor setup, when your RC-system shuts down in flight.

Jürgen
Hey now,
Oh come on, this is a red herring. Certainly no reason to go brushed over brushless. With *any* ESC using BEC this could be an issue, it has nothing to do with B/BL issues. For that if you're really concerned, just bypass the BEC; use an U-bec, S-bec, Park-BEC or as I and the rest of the hot rodders do, carry a small reciever pack. My Avionik has a set of 110 nimh cells to power the radio, my larger models carry a set of 720s, and if I were to go with the little out runners in my TSII I'd carry a set of 350 nimhs.
Solves the problem right off.

At this point most of my models are running BL motors (and LiPos) and it's turned some real dogs into rather nice flying models either by weight savings or more power, sure some had the issuse of BEC or not to BEC, but even with the reciver batteries they still out preform their cheesy can motors counterparts. About the only exception for me are:
My Wingo trainer (I keep it around for friends to try) with a S400 6v.
Sonic Liner with it's twin 480BB motors, it'll never be fast no matter what and I'd rather run the twin Kontroniks in my T.J.
And maybe this new TSII.
RobII
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Old Mar 07, 2006, 01:02 PM
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Jurgen Heilig's Avatar
53859 Niederkassel, Germany
Joined Sep 2000
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Quote:
Originally Posted by elfwreck
Hey now,
Oh come on, this is a red herring. Certainly no reason to go brushed over brushless. With *any* ESC using BEC this could be an issue, it has nothing to do with B/BL issues.
...
RobII
That's what happens when you don't read all the information I have already given in this thread. Of course the BEC issue has nothing to do with brushless, but usually the 40A ESC for the brushed motors have a much higher rated BEC then the usually smaller ESC's for the brushless motors.
We are also talking about using 3s Lipos here. Most people use only 7-8 NiXX cells with their brushed setups, making life a lot easier for the BEC.

Jürgen
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Old Mar 07, 2006, 01:45 PM
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United States, CA, Oakland
Joined Dec 2002
2,336 Posts
Hey now,
No, I did read all of the info. Plenty of the larger, 40 amp ish brushed ESCs don't have enough juice for four or more servos even on eight cells.
It's also a silly reason to not use BL motors in a model.
If that's the only reason not to go BL, it's not reason enough for anyone who's willing to work it through.
I figure that bypassing the BEC makes it much easier on the ESC, that way 7-8 BRJs or 3s LiPo machs nix.
Not that it really matter if you're having fun with the model...
RobII
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Old Mar 07, 2006, 02:20 PM
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53859 Niederkassel, Germany
Joined Sep 2000
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Quote:
Originally Posted by elfwreck
Hey now,
No, I did read all of the info. Plenty of the larger, 40 amp ish brushed ESCs don't have enough juice for four or more servos even on eight cells.
...
RobII
The 40A ESCs I am using usually have a 3A BEC - for example:

slim-40 3A/3W
up to 6 cells max. 6 Servos
up to 7 cells max. 5,6 Servos
up to 8 cells max. 4 Servos
...

Please not that even a 3A BEC is limited to 3W!

Jürgen
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Old Mar 07, 2006, 04:32 PM
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United States, CA, Oakland
Joined Dec 2002
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Hey now,
Sure your ESC has enough for this, and I believe my Pegasus does as well, but some of my older ESCs don't have enough BEC power for four servos even on eight cells.
Like I said before, dumping the BEC and going with a reciever battery or u-bec/s-bec makes all this moot.
To BEC or not to BEC is no reason to choose one over the other.
Cost may be, eff. may be, but BEC? that's no reason.

Right now I have the choice of going with:
Kontronik 400-23s (like I'd rip them out of the Twin Jet )
E-flite 370-1320s
Permax 480s
Permax 400s

Right now I'm leaning towards the 480s, not because of the BEC thing, but because the 370s would be fun in a twin 3d model.
The 400s? Why bother if I've got the 480s?
What ever choice I make won't be due to BEC or cost, as I've already got the bits for all of these...
I may wire the wing for both kinds of motors, that way I could swap things around as I please.

On the build side; I've filled all the mold dents with spackle and got them sanded smooth except for the fuse, but I still don't know what colours I want to go with. The Wife wants me to go with psychedelic fluoro and I want something that won't make my eyes bleed...
RobII
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Old Mar 07, 2006, 05:47 PM
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halifax nova scotia canada
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Are any of you glueing the wings together. THE WALRUS
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Old Mar 07, 2006, 07:27 PM
KY3JBD
lebanon, PA
Joined Dec 2000
692 Posts
Hi, Walrus, i glued my wings together, i dont need two piece wings as transporting is not a problem, and i just feel more secure with the wing glued. I almost have my twinstar completed with two brushless 400xt motors and a controller in each motor bay, pics and flight report to follow soon, (i hope) ....
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Old Mar 07, 2006, 07:44 PM
KY3JBD
lebanon, PA
Joined Dec 2000
692 Posts
Here are a couple of pictures of what i have done so far showing the motor install. I used 2 y harness for the speed controll and aileron coming out of wing since i glued them together and wont be seperating them. I just fired it up and it works great!! i need to get it done so i can fly and give a report.....Wit.
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Old Mar 07, 2006, 08:04 PM
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United States, CA, Oakland
Joined Dec 2002
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Hey now,
When I go flying I go for the whole day to a site that's about thirty miles from me. There's *great* sloping there as well as a nice E-field.
Point being, that I take a number of models with me; three or four E models and two to four slopers, sometimes more. The kicker is I drive a 928 Porsche, a-yup, a German Camero. It's *tiny* in the cargo area so I have no choice but to leave the wing two piece. It's hard enough getting my Millinium (3m slope racer) in there, never mind everything else.
Beside that I think it's more crash safe as a two piece, not that I plan on crashing
RobII
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Old Mar 07, 2006, 09:19 PM
KY3JBD
lebanon, PA
Joined Dec 2000
692 Posts
Elf, thats great i wish i had a porsche! but whatever works for you fine, the wing is not a issue for me since i drive a jeep cherokee so i made it one piece....
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Old Mar 07, 2006, 09:59 PM
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United States, CA, Oakland
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Quote:
Originally Posted by witstick
Elf, thats great i wish i had a porsche! but whatever works for you fine, the wing is not a issue for me since i drive a jeep cherokee so i made it one piece....
Hey now,
Yeah, it *sounds* good, but a twenty year old sports car, I dread smog tests and parts are killer. I'm not going to lie, it's a blast to drive and the price was right (free), but all in all I'd rather have a solid Dodge 3/4 ton van with windows. I get all my model stuff in the Porsche and there's barely room for me. It'd be nice to have more room so I could take my kids with me sometimes. Oh well, if that's all I can bitch about life must be pretty good
RobII
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Old Mar 07, 2006, 11:56 PM
Curse you Red Baron!
Grassy Knoll's Avatar
North & East of Sacramento California
Joined Apr 2004
567 Posts
Thinking of getting a trailor for the fleet

Quote:
Originally Posted by elfwreck
The kicker is I drive a 928 Porsche, a-yup, a German Camero. It's *tiny* in the cargo area so I have no choice but to leave the wing two piece.
RobII
Yea I know about that space problem.
When I go flying I usually pack in 6 to 10 planes in the back of my Hummer Type 1. (yellow of course.)

I break down some but others I leave intact. Like the Easy Glider Electric and the Cargo plane. It is too much of a problem to break down.

I am thinking of getting a trailor for it though. That way I have a little more room.


Brandie
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Old Mar 08, 2006, 02:18 AM
Need more time....
MarkFitzgerald's Avatar
Stuttgart, Germany
Joined May 2003
245 Posts
TSII Maiden

I received a TSII from my wonderful wife for Christmas and finally was able to maiden it this weekend. I upgraded it to the suggested configuration that is posted on the Multiplex German site:

Tuningmöglichkeit: (Tuning possibilities)
je 2x erforderlich (2 each needed)
Brushless Motor BL-X 22-18 (tiny, but powerful!)
mit Regler MULTIcont BL-27 (Regler=controller)
APC Propeller 8x3,8"
TP 3200 7.4V lipo

I didn't do any other mods and tried to keep it light. The battery sits almost all the way up front to balance. At full throttle it showed almost 200 watts on the Wattmeter. Amps is okay for the two controllers. Flies up out of my hand with a small push and cruises at hlaf throttle. Here it a couple of pictures. I made decals of my favorite NFL team! I'm very impressed with this plane.
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Old Mar 08, 2006, 03:30 AM
Got shenpa?
flieslikeabeagle's Avatar
Los Angeles
Joined May 2004
10,940 Posts
Quote:
Originally Posted by Jurgen Heilig
The difference between having to waist 2.5W and 6.25W enormous (250% more to be precise ) and many small ESCs won't be capable dissipating the resulting heat without direct air cooling.

No point in having a more efficient motor setup, when your RC-system shuts down in flight.
No point in throwing away 50% of the power output your motors are capable of, when a simple BEC upgrade will fix the issue.

Using the new Jurgen logic, all RC planes should be flown using only one single servo. After all, using 4 servos on a plane amounts to a 300% increase in power drawn by the servos, and this must be avoided at all costs.

Seriously, as I mentioned before, it's quite true that many small BEC's cannot handle 4 servos on 3S. But I think that's a very poor reason for throwing away the huge advantages of using a higher voltage lipo pack, when it is so easy to work around the problem if necessary: just buy a Dimension Engineering Parkbec, or a UBEC, or use a $1 surplus automotive cellphone charger (they have a switching regulator built in: http://www.rcgroups.com/forums/showt...hing+regulator ).

-Flieslikeabeagle
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Old Mar 08, 2006, 03:46 AM
SlopeHead
jcosta's Avatar
Lisboa, Portugal
Joined Jan 2004
2,882 Posts
Quote:
Originally Posted by flieslikeabeagl

Seriously, as I mentioned before, it's quite true that many small BEC's cannot handle 4 servos on 3S. But I think that's a very poor reason for throwing away the huge advantages of using a higher voltage lipo pack

-Flieslikeabeagle
Other than being 25% lighter, which does not really matter for the TS2 as you need lead to balance it with some lipo packs, and costing at least 3 times more than an 8 cell NiMH pack, and taking 3-4 times as long to re-charge, which are these huge advantages?

I think it is time for the essential questions:

- Have you flown a stock Twinstar 2???

- Have you flown your 2-3 times more expensive Twinstar 2?
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