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lennyshotgun
01-09-2006, 10:32 PM
Hi all
Just completed my first flight (with instructor of course) I have a Hobbico Super Star electric and we had a hell of a time keeping it on the runnway long enough to get it off the ground - fishtailed all over the place. The gear would start to vibrate and shake and it would veer off the runway.
Anyway - I would really like a Nexstar - seems to be the best trainer out, tricycle gear, but it only comes glow and I really want to stay electric.
Anyone out there with experiance converting it to electric.
Lenny

Rugar
01-09-2006, 10:47 PM
Hi Lenny, Welcome to WattFlyer!
I could be wrong, but I believe the Nexstar only comes in a RTF (ready to fly) version. I don't see why it wouldn't make a good conversion to electric, but buying a RTF plane and stripping it down and then converting to electric would be expensive unless you have some other use for the glow motor that comes with it.
You might want to look at the Telemaster 40 kit if your willing to build or the AFTF (Almost ready to fly) Senior Telemaster from Hobby Lobby. The 40 version is on sale for $89.00 right now.
http://www.hobby-lobby.com/telemaster40.htm

http://www.hobby-lobby.com/srtele-arf.htm

lennyshotgun
01-09-2006, 10:59 PM
One of my fellow club members has one that he will sell me cheap - He's used the engine in another model - I just don't know what size motor, will it fit the existing engine mount... - what else needs to be done as far as a place for the battery ...

Rugar
01-09-2006, 11:17 PM
You would probably need some along the lines of a Axi 4120. The existing Engine mount would have to be changed to a Motor mount for a electric conversion. You would also probably have to make a hatch for installing/removing the battery without having to remove the wing. I'm not sure how much work this would be to convert over as Ive never seen one up close. Without knowing your mechanical/building skills, this might be a project more suited for a someone with a few conversions under their belt. I'm sure it can be done, but you will have to do some more research. Maybe someone else with experience with this plane, or has done the conversion already may be able to help you more.

TManiaci
01-10-2006, 12:54 AM
Hey Lenny,

Yea, we converted a Nexstar to E-Power. Running an AXI 4120/18 on a 15x10E, using an 18.5V 5S2P 8000 mAH making a respectable 1045 Watts. It has plenty of power, and flys just about like it did with the OS 46 on board. The AUW is 7.8 lbs and measuring thrust at approximatly 7.2 lbs. Not too bad. It sure is weird flying in silence like this.

You will need to be careful with that prop, it's VERY close to the ground and a bumpy runway dings it up. If I were starting over, I would have bought a 6S2P in a 6000 mAH range and run a higher rpm so we could prop it down to a smaller diameter. The Kv on the 4120/18 is so low (510), you can't swing a big enough prop to load it up and make the power you need on 5S voltages.

Alas... it works well. We've only flown it a couple times, but it is real fun.

lennyshotgun
01-10-2006, 01:16 AM
Tman
I'm real new but pretty good with my hands and not afraid to try - Was this something you would recommend for a first attempt at conversion - anything else you would have done defferent.
If I'm understanding, the 6s2p is a battery? The "6" battery raises the RPM allowing for a shorter prop?
Can u take some pics of the cabin setup for the battery and the engine mount ... lenny@shotgundelivery.com
Thanks
Lenny

TManiaci
01-10-2006, 03:46 AM
Lenny,

Yes, you're on the right track. The motor is ratred with a Kv number. That represents the RPM per Volt it will turn. Batteries (Lipo) are rated by the number of cells (3.7 volts per cell) and the capacity in mAH (miiliamp hours). So, a 5S is 5 cells in series, and 2P means two parallel cell packs of 5 cells. So, in this case 5S is 5 x 3.7 = 18.5 volts, and 8000 mAH is two 5 cell 4000 mAH packs wired parallel.

Then, 18.5 Volts x 510 rpm/volt = 9435 rpm (no-load). The reality is a fresh battery with proper nominal propeller selection to load the prop to generate the thrust will draw that rpm down consideraby. We should target the optimum rpm for a given sport propeller around 11,000 rpm to get best results. So, you can see that the 5S pack is turning too slow, and therefore to compensate you have to put a much larger diameter prop. Hence, I had to put on a 15" prop to get the thrust up high enough and load up the motor.

On electrics, you select a power range for a given flying style, in this case a trainer is simple pattern flight. You need about 50 watts per pound minimum for a trainer with simple pattern flying. For an acrobatic plane, you need 100 W/lbs min., and for 3D stunt flight you need 150 W/lb min.

That wattage range then dictates the equipment selection. So, for a 8 lb plane we shoot high at 100 Watts per lb, and need 800 watts (final thrust power). You then divide by the prop/motor efficiency, typically 75-80%, and estimate you should draw around 1050 watts (800 watts / 0.75). That's all ballpark, but you get the idea. Now you go pick out a motor that makes that kind of power, and then match up a battery and ESC that will support it.

Here are some pict's of the install. We fabricated a block to push the outrunner reversing kit out to get the prop to the right position, and this method maintains the proper thrust angles. It's basically two layers of 1/2" balsa, sandwiched in 1/8" ply. There are 4 long screws that go thru into the origonal motor mount blind screw, then 4 blind nuts in the back of the block that the Outrunner backplate mounts to with long screws. It's a bit of fabrication, but if you're good with tools it's not too bad.

The battery is just in the bottom of the plane up front on a pad of foam with a velcro strap. It's not all that hard.

lennyshotgun
02-04-2006, 09:24 PM
Ok Tman
I've not responded to this for a while - been doin a lot of posting and a lot of reading and I think I'm starting to understand.
I'm trying to keep the battery at 5s max or I'll need to buy new charger ...
It looks like the axi AXI 4120/14 turns 650 per volt and with a 5s it should handle the 8 pounds and allow me to come down to a smaller prop.
Was there a reason you chose the 4120/18 instead?
I'm still in the dark about how to predict the total wattage in advance but i'm getting there.
Thought I would run it by someone whos done it and see if my logic/calculation makes sense before I order anything.
Thanks Lenny

TManiaci
02-05-2006, 01:57 AM
Was there a reason you chose the 4120/18 instead?

I didn't buy this stuff, and it is not the optimum setup. The 4120/14 is a better choice on a 5S cell (18.5V). That's why we had troubles putting a prop big enough to make it work. Not enough ground clearance. The 4120/14 needs a 6S cell, but my father-in-law bought a custom 5S2P 8000 mAH battery that we couldn't return, so it was a little mixed up. There was motor swapping and stuff, so we got what we got. It works, but it would be a bit better with the 4120/14 matching the 5S pack.

So, there is a better choice for you here. The 4120/18 is a good choice if you go with two 3S 3000-4000 mAH lipo's wired in series, making it 6S1P. Then you can charge each cell with your existing charger. That makes a reasonable size prop selection work out too, maybe a 12x6E or so.

I'll do some calcs and see if that's a good plan, but it's making good sense right now.

FordGT145
04-01-2006, 10:22 PM
Check out Hobby Lobby. They did a complete conversion and give you all the info.
Hobby-lobby.com

jayree
04-17-2006, 08:32 AM
I have modified three Nexstars. Its is a very simple operation. You can use the same motor mount and bulkhaed without any problem. I use Phasor 45-3's with a hose clamp to hold the motor to the mount and it flies well. jayree

Twmaster
09-01-2006, 01:47 AM
I realize this is a kinda old thread but here is the link to the conversion Hobby-Lobby did to fly the Nexstar 46 electric:

http://www.hobby-lobby.com/g2e-hobnexstar46.htm

Hope this is of help to somebody.

laxlife
09-01-2006, 05:38 PM
I did this conversion last year. First I mounted an Axi 4120 but the prop diameter it required was much too large for any kind of safe clearance so I downsized to an Axi 2826-12 with a 12" prop and a TP 3s (11.1volt) 4200 mAh lipo brick and it works much better than with the bigger motor. It doesn't race around the pattern; it just flies much more like a trainer. I too have trouble keeping tricycle gear running a straight line down the runway on takeoff. Its an art I guess. If I had to chose I think I'd say that I prefer my Avistar 40 trainer as an electric flyer. As far as a conversion project I'd say they are all very similar even 150 sized and even twins. In fact the electric plumbing is pretty much the same for all size plane conversions, just bigger components, lipo packs, ESC's, motors, etc. My son is a great pilot so I can build planes that are out of my league to fly and he can fly the. We've done tons and the electric guts are pretty easy and straight forward once you learn how to solder. That takes practice.

Twmaster
09-01-2006, 05:41 PM
That AXi 2826 is an oft overlooked motor in the .40 sized conversion game. Amazing power they can make.

:D

Twmaster
09-03-2006, 05:45 AM
I did this conversion last year. First I mounted an Axi 4120 but the prop diameter it required was much too large for any kind of safe clearance so I downsized to an Axi 2826-12 with a 12" prop and a TP 3s (11.1volt) 4200 mAh lipo brick...

What did this end up weighing?

MAKODS
09-05-2006, 04:27 PM
E-flight 46 with 10 x 7 APC and 5s1p4000 Lipo. Its really fast and goes vertical for at least 200ft. My club mates are amazed.

laxlife
09-05-2006, 04:36 PM
AUW?
Sorry to take so long in responding. I was hoping to find my notes on my flying weight. I think its about 5.5 lbs. I don't get 50 feet of vertical let alone 200 feet. I may repower to an e-flight 46 too! If it spins a 10x7 with that kind of 5s authority then this motor fills the gap in the Axi line between the 2826 and the 4120 where 10" props just don't put out as much power. Prop size is a real problem as a limiting factor in some multiengine conversions I've undertaken and the e-46 could solve that problem.

Twmaster
09-05-2006, 04:43 PM
Thanks for the weight WD.

I just finished converting a Kyosho Calmato Trainer to e-power and came up at 5 pounds, 6 ounces AUW.

Just an FYI, the E-Flight Power 46 is nearly identical in performance to an AXi 4120/14. It's also nearly identical physically.

MAKODS
09-05-2006, 07:11 PM
Yes it is a good combination and I am very impressed with the E-Flight motors. I have 2 E-flight 25's also in 3lb sport planes. My AUW for the Nexstar is 6.1lbs with 22oz being battery. I draw about 38 amps wot and use a Castle 45 esc with no problem.

MustGoFaster
11-16-2006, 08:46 PM
My boss at work bought a nexstar coverted with an eflite 46. right now, it has a 60 amp esc, 3s2p 4200 lipos, 12x6 prop and it won't get off the ground - jsut sort of hops along.

if he steps up to a 5s lipo and a 10x7 - will the 60 amp esc hold out?

afineman
11-16-2006, 11:46 PM
MustGoFaster

My brother converted his Nexstar to electric using this motor http://www.warbirds-rc.com/Store/hett291214.html

A 11X7 prop with these ESC http://www.raidentech.com/brelrcspcofo.html

and 3S2P Dymond Models 15C Lipos .

and the video http://media.putfile.com/smoke-66

He get 10 + min flight time, something doesn't sound rite.

tell your boss, he need to put a watt meter on it.

Brent

dmmalish
11-17-2006, 02:31 AM
glad to see i'm not the only clown to try smoke bombs sure wish there was a good smoke system for electrics thats what i'm waiting for any ideas please post them:rolleyes:

laxlife
11-17-2006, 04:16 AM
The stats for the Eflite46 rate it for 40amps and 5s Lipo's. That's a big motor (too big?) but the prop you've mounted is too small IMHO. I use an APC 13x10 on my Nexstar and I've only got an Axi 2826-12 on 3s. I first tried an Axi 4120 (equivalent to the eFlite46) and didn't have enough power either. So I yielded to the counterintuitive idea that a smaller motor (lighter) was the way to go. Now the Nexstar flies great. Not 3d, no vertical but just fine as a trainer. PS I didn't use the leading edge pasties.

MustGoFaster
11-17-2006, 02:03 PM
wow - how'd you get a 13" prop on the nexstar, with the 12 there's only about 3/4" or so clearance between the ground and the prop already. maybe we need to find a way to extend the wheels a little farther or something like that. He's going to have to check his motor mount too, might have it mounted too far below the centerline to work properly

allena99
11-17-2006, 09:18 PM
I did this conversion on my NextStar, which is the ARF version, not the RTF version. I had been flying it with a RCV 58CD 4-stroke, and used the AXI 2826-10 motor, and a 12x8E prop. The only batteries I had at the time were 2000mAh NiCd's. My ESC limited me to 40A, so I had to go a little conservative on the prop size. The plane flew about the same as with the glow engine, even though it was a little heavier because of those batteries. Take-off roll on grass was fairly short, about the same as the glow engine. The flight times were very short, about 4 minutes because of the battery I was using. I had used that AXI 2826-10 to convert a Twist-40, and a GP SlowPoke-40. I have finally started to play around with LiPo's, and would like to do these conversions again, especially the Twist 40.

laxlife
11-18-2006, 05:33 PM
Yer right MustGoFaster there is only about 3/4" clearance for the prop but thats proven to be enough

cloud-9
10-28-2007, 11:03 PM
Hi all
Just completed my first flight (with instructor of course) I have a Hobbico Super Star electric and we had a hell of a time keeping it on the runnway long enough to get it off the ground - fishtailed all over the place. The gear would start to vibrate and shake and it would veer off the runway.
Anyway - I would really like a Nexstar - seems to be the best trainer out, tricycle gear, but it only comes glow and I really want to stay electric.
Anyone out there with experiance converting it to electric.
Lenny


An electric version of the NextStar just came out. There is a thread somewhere here about it, but you can easily find the company website.

Jim

laxlife
10-28-2007, 11:17 PM
I had similar ground control problems. I learned to live with it. The Hobbico Avistar tricycle geared trainer flew well and had better ground control but the difference wasn't that big. Best trainer? I since converted and flew a Senior Telemaster and it was a GREAT trainer even if it was a taildragger. That monster 8 foot wingspan practically flew itself!

cloud-9
10-28-2007, 11:21 PM
I realize this is a kinda old thread but here is the link to the conversion Hobby-Lobby did to fly the Nexstar 46 electric:

http://www.hobby-lobby.com/g2e-hobnexstar46.htm

Hope this is of help to somebody.


Wow, that's confusing. How could two such different motors be good conversions for the Nextstar?

AXI 2826/12 (Hobby Lobby selection)

AXI 4120/14 (mentioned above by TManiaci)

Jim

flyer88
02-26-2009, 08:16 PM
Finally complete ! Can't wait to fly her, she's gonna be great !

1026 watts on 4s/4000mah


To checkout the photos of my conversion: go to Photobucket.com and search Nexstar

Fly it low !

Flyer88