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Jan 19, 2007, 04:46 PM
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multiplex easy glider brushless upgrade question


Does anyone know how the below setup on the ez glider would work in comparison to the multiplex upgrade kit?
motor- tornado 480 sized brushless
http://www.e-flight.co.uk/shopexd.asp?id=88

with a 25 amp castle creations ESC
http://www.e-flight.co.uk/shopexd.asp?id=88

and a thunder power 1320 2 cell lipo
http://www.hobby-lobby.com/thunderpower.htm

direct drive with 6x3 prop
thanks
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Jan 19, 2007, 06:21 PM
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pinolefm1's Avatar
What's included in the upgrade kit ???

Steve
Jan 20, 2007, 02:39 AM
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Thread OP
this is the upgrade kit http://www.sussex-model-centre.co.uk...d.asp?id=19880
here is more info on the motor http://www.multiplexusa.com/motors/B...00/6Direct.htm
They suggest a 7.4 2100mah but I have a 1320 11.1 what difference will this make?
thanks
Jan 20, 2007, 11:43 AM
Electric Airplane Junkie
bhchan's Avatar
I would stay with a geared unit and a larger folding prop. The EZG is a large glider that will not work too well with a small fast spinning prop. Also the nose of the EZG is wide so a 6x3 folding prop (you are planning to use a folding prop, aren't yoU?) will not fold properly. A non folding prop will spin constantly and creat a lot of drag for the plane.

As for the difference between 2S 2100 and 3S 1320, the lower voltage,2S 7.4V, (on a given motor) will reguire a larger prop to get the power out of the motor. With higher voltage,3S 11.1V, you will need to go with a smaller prop to keep the current down. Assuming the cells will provide 15C discharge, the 2100 can handle 31 amp and the 1320 can only deliever 20 Amp.

Brian, an EAJ
Jan 20, 2007, 01:11 PM
If it floats....sail it!
FoamCrusher's Avatar
Using "15C" rated cells at their full rating will guarantee you get only a few cycles out of an expensive investment. In order to get reasonable life out of them, the conventional advise is to run them at no more than 80%C, and less is better. Yes, you can push the envelope and they won't explode, but unless you have a thick wallet, buying a new pack every 50 cycles is going to hurt. Run at 80%C and properly balanced and charged, you should get 300+ cycles of out them.

For a 15C 1350mAh pack 80%C would be 15 x 1.350 A x 0.80 = 15.6A continuous, and if they are rated at 20 burst, then 20 x 1.350 x 0.80 = 21.6A for 20 seconds or less. You can use one of the software predictor programs like MotoCalc to estimate the amp draw with different size props to see if what is being recommend will work. Just remember these programs only get you to a ball park number and you should compare the prediction to actual static current with your motor, your prop and your pack. There is a simple version of such a program on the Multiplex website.

Brian is right on. You are looking for a system with about 75 Watts/Pound to get decent performance, or 100 W/lb to get stellar performance. Since Watts are Volts x Amps, you can run more current or more voltage to get more power.

Brushless motors generally like more voltage, so running a 3 series 1 parallel (3S1P) pack in place of a 2 series 7.4 V pack is an easy way to up the power. However, since more voltage will turn the prop faster, you must go to a smaller prop to keep the current the same. Unfortunately, small props are inefficient when compared to larger props, so it is better to gear the motor deeper and run a higher voltage rather than to run more current and a small prop. For a sailplane you want a combination that gives lots of thrust at a low tip speed, and this usually means a motor/gearing combination that will get you about 800 - 900 Kv at the prop (motor Kv divided by gearbox ratio).

As an example, I have run a Mega 16./15/3 (3000 Kv) in a 5.2 :1 gearbox and can use a 14 x 8 prop to keep the 3S1P TP-2100 mAh packs at about 21A; well within 80% of their rating. This gives fantastic vertical performance at 115 W/lb, or more lifts to winch height using some throttle management and potentially long battery life. ~Moderation in all things....even moderation~

FC
Jan 21, 2007, 11:35 AM
Registered User
Thread OP
Thanks for all your time and advice.
So would I be better off using this motor and esc but buying a gearbox, larger prop and 2100 2s lipo instead. If so what gearbox(I have never had a gearbox in any of my planes before as they are mostly speed 400 pylons) and prop?
How would this perform?
Jan 21, 2007, 01:31 PM
If it floats....sail it!
FoamCrusher's Avatar
First you need to settle on what level of performance you want; mild, moderate or stellar, and how much money (read that as quality of the motor/gb) you want to spend. Personally, I discard the cheap/mild set ups right away and go for at least moderate performance and quality.

You can read this rather long thread and find many combinations that seem to work well, including using an outrunner type motor that does not require a gearbox. The inrunner combinations usually use a Speed 400 to 480 size brushless motor (28mm OD can size with mounting holes on 16mm and 19 mm centers) of around 2500 - 3500 Kv with a gearing to drop the Kv at the prop to anywhere between ~500 to ~900. A higher Kv motor with deeper gearing is more efficient and allows the use of a larger and more efficient prop.

Combinations of 3:1 to 3.5:1 and about 2500 Kv work, as do 5:1 at 3500 Kv, with the latter being more efficient. You could even pair a 2000 Kv motor with a 2.5:1 box and get very reasonable performance. If you want to stay with that Typhoon, a 2:1 or 2.5:1 box would work fine.

I have tried the cheaper motors like the Typhoon in that upgrade kit, including Himax and Warp4, and find I always come back to either Razor, or Mega - they are sturdier and in the long run give me better performance at a reasonable cost. If you want real platinum level quality with a commensurate price, go with Neu or Lehner, with Hacker just a little behind.

Gearboxes are much the same, with MPJ on the cheap end, Model Motors and the Mega house brand in the middle, and Maxon, Kontronic, or the house brand used by Neu at the top end. Just be sure to buy a gearbox that includes a pinion that has the correct diameter bore for the size shaft of the motor you have unless you purchase the motor & box as a unit. Speed 400's use a 2.3mm shaft, and the better quality brushless motors use at least 3.17mm (1/8") so a box designed for a Speed 400 may come with a pinion that won't fit your motor - others include or can be ordered with either size pinion.

I hesitate to recommend an exact combination since I would be making assumptions on the amount of money you want to spend.

Just look at the motor and gearbox sections of the various suppliers from whom you usually purchase to see what they have. You can also order from places like Aircraft World in Japan http://www.aircraft-world.com/default.asp who has lots of different items, fast delivery, and inexpensive shipping.

My current EZG has a Razor Motors 2500a (3850 Kv with a 4.4:1 gb) - now being sold by Neu Motors. This is a light set up limited to about 30A on 3S1P 2100 mAh packs with an 11 x 6 prop. It climbs very well at about 1400 ft/min and gets 8 to 10 high lifts due to the light weight of the motor/gb combo. It does not go as well as the Mega system in my prior post, but then again, it won't rip the motor mount off the stock unreinforced nose either

FC
Jan 21, 2007, 03:02 PM
Registered User
Thread OP
I really don't have any more money to spend so ideally I want to stick with the same motor and esc and change the lipo to a 2100 7.4 and get a gearbox, I think the tornado motor is 3600 kv so you think I need a 5:1 gearbox right? Who makes the cheapest gearboxes and roughly what size prop would you suggest? thanks again for all your time foamcrusher.
Jan 21, 2007, 03:52 PM
If it floats....sail it!
FoamCrusher's Avatar
I ran that motor through the Multiplex calc program on 2S1P TP-2100-PL, the Multiplex 4.4:1 gb shown here http://www.multiplexusa.com/motors/B...00/6Direct.htm as part number M332466, and a 12 x6 folding prop and got about 29A and 40 oz of thrust at about 150 Watts - all well within the motor and pack. That should push it nicely and will obviously fit without any trouble. That may be the easiest thing for you to do until you learn more about how to pick power set ups and which direction your tastes lean.

Perhaps someone who has that specific combination can comment about how it performs in real life, which can often be a bit different than what the prediction program guess.

FC
Jan 21, 2007, 05:01 PM
Registered User
Thread OP
You have been a great help and it has been much appreciated!
Many thanks
Jan 22, 2007, 03:44 AM
Registered User
A powerful way to upgrade the easyglider:

http://www.miliamperios.com/foro/viewtopic.php?t=62303

regards
Jan 24, 2007, 05:23 AM
Registered User
Hi there Foamcrusher,
Thanks for the good info on the EGE with upgrade motors, it is great to get good information.
I went to the Neu site, to get a similar setup to yours, but couldnt find it.
It appears that the gearbox comes with the Neu motors only?
Or have I got it wrong/
I want to buy the razor motor and GB as a combo,for my EGE, so as to ensure that the pinion will be matched?
Any advice appreciated?

bax2
Jan 25, 2007, 01:38 AM
If it floats....sail it!
FoamCrusher's Avatar
Quote:
Originally Posted by bax2
Hi there Foamcrusher,.....I went to the Neu site, to get a similar setup to yours, but couldnt find it.
It appears that the gearbox comes with the Neu motors only?
Or have I got it wrong/
I want to buy the razor motor and GB as a combo,for my EGE, so as to ensure that the pinion will be matched?
Any advice appreciated?
bax2:

Neu has just taken over selling Razors and nothing is on their website last I looked, you have to email or call them. They are in very limited production of the 300, 350, 400 and 2500. When Matt Orem was selling them he had a Razor 2500 as the motor only and the 2500a as the motor with a 4.4:1 Maxon gearbox. I do not know if Neu is actually selling the one with the gearbox in addition to just the motor. If you can only get the motor, AirCraft World in Japan used to sell the gb as a replacement part, but I don't know if they still have them.

I wrote Neu the other day since I have a bare 2500 motor I bought used that has a "Razor Saver" on the end (that is a thicker endbell that won't strip out the mounting screws as easily) to see if I could get a replacement bell and bearing, and they said yes they had them. I have a new gearbox with the adapter plate, but the motor with the thicker endbell won't take the gb because the shaft ends up too short for the pinion to mesh. With a stock endbell it will all go together and I will have another power unit.

FC
Jan 27, 2007, 01:24 AM
Registered User
For anything similar to MPX Easy Glider. If the fund is too tight, I would highly recommend those GEARED Kontronik's. Those geared FUN series, eg 480-28+5,2:1 . and 500-27+5,2.... or bigger FUN 600 series are both excellent choice for e gliders and furthermore I just found /confirmed by open the case to compare with their older BL series, that FUN series have segmented magnets which should be good for continuous run in other applications.
I have several pcs of those older geared BL series motors, they have been working great for me/ my friend for over 3 years, especially under my abuses , those old things could take 170A+ !
One more things to notice, DON'T try to add a gearbox later on ,unless you or your friends have appropriate tools, experience and much time/ effort to be spared.

David
Jan 27, 2007, 02:08 AM
If it floats....sail it!
FoamCrusher's Avatar
bax2:

I talked to Neu today and they said sorry....2500 motors only and not the 2500a with the gb at this time

C-MIC: The Kontronic 5.2:1 gear box bolts right up to a Mega 15/14/XX with only a little Loc-Tite to hold the pinion and screws. That's what I have on my Mega /3 and it is great. It is a little heavier than other gearboxes, but that is why it can take all that power. They are available here http://www2.towerhobbies.com/cgi-bin...?&I=LXGFN9&P=7 (Note that their tech description of the pinion being a 3mm bore and not a 3.17mm bore is incorrect. It is 3.17mm; the same size as the Mega shaft.

FC


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