DMehalko

My Feedback: (42)

Ok guys, Last spring (2003) i built an Uproar 40 from tower hobbies and flew the crap out of it until i sold it in the winter of '03. It was powered by a 46FX and loved the way it flew. Totally regreating selling it, i am ready to build another one, this time, electric. My backround in electric isnt big, many small park flyers (slow sticks, wattage foamies, and other small 280-300 size brushed planes) but none of them dealing with brushless. Anyway, here is how i want to do it as i want about the same amount of power.

Axi 2826/12 with the jeti 40amp and a thunder power 3S2P 2100mah pack.
What my question really is is regarding power, will this fly a 3.5-4lb uproar? The site says it will but i fly at 5,480 absl. As you can tell, i am not very experienced in the electric department so any help or reccomendations would be awesome.

This was my old Uproar

Matt Kirsch

My Feedback: (21)

AXi's website says a 14x10 prop with that motor and battery. It won't be fast, but spinning that large of a prop and putting out 350 Watts, it should hover the plane if you can keep it down around 3.5 pounds or less.

There should be plenty of opportunity to save weight on that Uproar.

DMehalko

My Feedback: (42)

I have never built a larger electric like this, but will it wiegh more with the electric setup even with the lithiums? My old uproar with a 46FX weighed about 3.7lbs, all standards and a micro on the throttle. On this one i will use mini's in the wings and maybe mini digitals in the tail.

Also, what kind of flight times should i expect with the 3S2P 2100 pack? Is this a good battery? I have only delt with nicads and nihm's.

If anyone is interested i might turn this into a build thread for a first glow to electric conversion for me.

Thanks
David

Matt Kirsch

My Feedback: (21)

Flight times will depend on the Amps you draw, and how you manage your throttle. I would imagine that with a total of 4200mAh at your disposal, and a peak current of ~35 Amps, you can easily run 10 minutes or more with throttle management.

Weight is pretty easy to determine. The weights of everything being compared, glow engine, motor, and battery, are posted on their respective websites. Also take into account a full load of fuel, throttle servo, tank, etc.. My money is on the conversion coming out pretty close, if not a bit lighter than the glow version with a full tank. (Note: 8 fluid ounces of fuel does not weigh 8 ounces)

3.7 pounds for the .46 size eh? Sounds like you build light in the first place.

jonnyjetprop

My Feedback: (3)

Matt,

What does a eight oz tank of fuel weigh? I don't have the fuel to weigh it.

John

Matt Kirsch

My Feedback: (21)

I don't know offhand, but I would estimate between 5 and 6 ounces. 8 fluid ounces of water at just above freezing weighs 8 ounces, and alcohol, oil, and nitromethane are all lighter than water.

DMehalko

My Feedback: (42)

Ya, i scraped out a lot of the hard wood the suplied and built it mostly with contest grade wood. At 5,480ft it would seriously ROCKET striaght up forever if i wanted at full throttle, most flying was done at 1/3 throttle.


Ok, so how will i determine amps drawn? And also regarding batteries, the 2100mah pack wont be enough? You mentioned 4200mah, so with the 2100 i could fly around 5 min?

Thanks for the help so far, i will be ordering all the stuff soon.

David

3dandpatternflyer

The pack u have is 2 in parallel. U have a 3s2p Thuder Power 2100. 2100x 2 = 4200 mah So u could fly around 10 minutes at 35 amps like Matt said with good throttle management.

TTYL,
Andrew T.

DMehalko

My Feedback: (42)

Thanks, that's what i needed to know, so the 3S means 3 cells, and the 2p is two packs in parallel? As you can see im new to lithium batteries.

David

Mike Parsons

Correct. As you increase the number of cells in S (series) you increase voltage..as you increase the number of P (parallel), you increase the amount of amps that the pack can handle as well as the total pack capacity (ie- runtime) . Lets say the 3S 2100 pack can handle 21 amps (10C), then when you combine another 3S in Parallel to form a 3S2P you now have a 42 amp capable pack and have doubled your capacity from 2100 mah to 4200 mah thus extending your runtime.

-Mike

Matt Kirsch

My Feedback: (21)

You have a TOTAL of 4200mAh at your disposal. That "3S2P" pack is two 3-cell packs of 2100mAh cells in parallel. The guys above explained how to figure it all out.

To determine Amps on your specific setup, you need a meter. This can be a heavy-duty laboratory DC ammeter, or one of the several products in the electric R/C plane market now that perform this function (e.g. Astro Whattmeter). You won't be able to read the current in flight obviously. The static full throttle current on the ground is good enough, because it's generally the maximum current the system will see.

You can get a rough idea of Amps by looking up your combination at the manufacturer's website, or by finding reports from others' tests.

Flying, if you don't run full throttle the whole time, you'll be drawing signifigantly less current. This will extend flight times. At full throttle, and 35 Amps, even a 4200mAh pack won't run more than about 5 minutes, so you know you can run at least five minutes. How much longer? It depends on how you fly. 10 minutes was just a general estimate based on my experience with a 40 Amp system on 4000mAh of LiPoly battery.

DMehalko

My Feedback: (42)

Excellent, thanks for all your help so far, and dealing to the motors again, is there a major difference between the 10 turn and 12 turn motor? Would i notice a difference?

stratosman

My Feedback: (13)

I just bought a Uproar to convert it to electric. I have a AXI 2820/10 motor will it fly the plane?This will be my first conversion. I have had uproars before and they are a kick to fly and cheap.
What size prop with that motor? I found out that they come down just as fast as they go up.

DMehalko

My Feedback: (42)

Not sure, im going to use the 28/26 motor. Anyway, my kit finally showed up, and will begin building as soon as i clean my shop to accept a new kit.

I will post pictures, and mods i will be doining through out the build.

David

DMehalko

My Feedback: (42)

Ok, i dont have my digital camera at the house right now so no pictures yet. Anyway, mostly scratch built the fuse with contest grade wood, and sheeted the top and bottom with 1/16" insted of 3/32" to save weight, so the fuse is complete and covered right now, will start working on the wings in the next few days.

Its going to be covered the same as the one in post #1 except with white instead of yellow.

And has anyone else have any experience with other brushless companies? I would like to consider all brushless options, i looked at hacker, but the are a little expensive.

David

RickC2009

My Feedback: (12)

How's the uproar electric coming along?
I was thinking of doing the same thing with the New ARF uproar. http://www2.towerhobbies.com/cgi-bin/wti0161p?&I=LWS368
If the ARF comes in at suggested Weight: 3.5 - 4 lb (1587 - 1814g) I think it will work out just fine. What do you guy's think?
Rickc

RiffRaff

My Feedback: (16)

I just finished my Uproar conversion. Seems to have turned out pretty well, though I really don't know too much about this electric stuff. Heck, I don't know much of anything about building either!

I just started flying this summer and have been doing very well so far. I have only planted one plane in about 30 or so flights and that was due to poor plane setup and trying to do aerobatics without proper altitude. I have flown an Avistar, Tower Trainer, A U-Can-Do 3D .46 and a Graupner Extra 300. Coming along pretty well. Up until now I have only assembled the above plans from ARF form. I decided to try my hand at a kit and chose the Uproar because it was cheap and looked fairly simple to build.

I had been reading here at RCU about all of this newfangled electric technology with brushless motors and Li-Poly battery systems and thought that I would really like to get a "real" electric plane to be able to haul around with me to do some quick flying with out the prep and cleanup of a nitro burner.

After doing some reading here I decided the Uproar was a perfect candidate for my first electric conversion and plus I already had the kit.

Keep in mind this is my first kit build and my first attempt at electrics.

Here are some details of the project.

Tower Hobbies Uproar kit
AXI 2820/12 brushless outrunner
Castle Creations 45 amp brushless ESC w/BEC.
Kokam 3S2P 11.1V/2000 mAH battery.

Standard full size servos for rudder and elevator. (One Hitec, one Hobbico lying around my parts box)
2 mini Hobbico CS-12's for ailerons (Had lying around also)
Hitec Electron 6 RX

The finished project came in at 3 Lbs 6 oz flight ready which I was very happy with. I was expecting 4lbs +.

I have a 11x6 prop on it now not having any clue as how to size the prop for this thing but I am very happy with the power this setup produces for now. The setup turns this prop at just under 9000 RPM. I had the 11x6 lying around. I have some 12's and 13's of various pitch as well so I will experiment when the weather permits.

The project took about 2 weeks to complete with many nights of very little sleep. I learned quite a few things about building in the past two weeks and am planning on a Bruce Tharp Venture 60 for a winter project (not electric, and I have the kit already).The motor mount was a makeshift attempt of fabricating and had to do it over again would take a completely different approach but it works and is very stout at 2oz. I was going to scrap it and start over but it works fine so I decided to keep it for now. The plane balances out very well with no need to add any dead weight. I need a break from building for a while. Burned way to much midnight oil on this little venture.

Here are a couple of pics. Yes, the decals are a bit odd, but they are what I found in my box o parts and just ran with it.

Just in case you are wondering, yes I do work for Bobcat. I am a mechanical engineer in their product development department.

Any advice on this bird would be greatly appreciated.

RickC2009

My Feedback: (12)

Riff,
Nice plane!
Can you tell us more about the flight?
Does it have unlimited vertical and how long of flight time are you getting?
PS AXI makes the radial mount!
Rickc

RiffRaff

My Feedback: (16)

The plane was just finished yesterday and have not maiden-ed her yet. I think I may get the chance this evening.

With the 11x6 it will not do vertical base on my shop tests. I am not a skilled enough pilot to try actual verticals just yet. I will need to prop up to get the thrust I need for unlimited vertical I am certain. At 3lbs 6oz this power system should be able to do it I imagine. I am really new to all of this stuff (especially electrics) so I am still learning.

I saw the mounting offerings from AXI but I wasn't sure what I would be needing when I ordered the motor so I passed, especially at $25. The mount I fabricated was pretty much free as it was all scrap balsa/ply from the build and it is very sturdy and came in at 2oz. I am actually quite pleased with it other that it looks like a wart on the plane and if I were to do it again I would take another approach. I have some machining equipment in my garage and will probably fabricate an aluminum radial mount when time permits. I get very impatient with this stuff and I just refused to wait another week for a mount to be shipped to me. My LHS doesn't do much electric except RTF stuff.

Thanks for your input!

I will report back after I get her in the air (hopefully after work today).

Riff

RiffRaff

My Feedback: (16)

Rick

Got her in the air this afternoon. It was a bit too windy for me and especially on a new plane and one as slippery as the uproar.

I didn't get to drain the pack as I broke my prop on the first landing. Had to put it down in some not so trim grass. This was with the 11x6. I stuck a 12x6 on and unless I raise her up some I think this is going to be the largest diameter I can comfortably put on her. Even at 12" I am goung to have to be careful with the landings.

In short all I can say is WOW!!!! This is my first electric and the performance way exceeded my expectations. This thing flew with all the authority of a nitro ship with ease. It far exceeded what I was expecting. I am now a believer in electrics that is for certain. I didn’t really get to do too much with her as the wind was a little much for an newbie like me and I need to lower my dual rates a bit. This thing is SLIPPERY!

This is one of those pleasant surprises though where my expectations were far exceeded. I am very happy with the performance and I am not even close to the best prop setup.

In a word… SWEEEEEEEET!

Riff

RiffRaff

My Feedback: (16)

I got out again tonight for a bit. This time on a 12x6 prop. The 12x6 is too much unless I raise her off the ground a bit. I broke this prop as well and all of the landings were very nice. The plane is way too fast for the field I am flying in here next to my house so I am going to downsize to a 10x5. The battery life on the 12x6 was great. I was not all out flying but I did about a half dozen takeoffs and landings and was air born for at minimum 5 minutes. I have not recharged the battery yet so I don't know haw many mAH I burned but performance was awesome! I am not a real good one to be a test pilot because my skills are minimal. Heck, I was proud just to be able to handle this thing and be able to land it smoothly. At 3 Lbs 6oz it lands incredibly easy. This uproar is awesome as an electric!

The wind was about 10 MPH and it did tend to toss the light plane around a bit. Still more than I am really comfortable with.

The plane takes off of grass with ease. Very short lift off run. Shorter than anything nitro I have flown to date. But the wing loading is so low at this weight I suppose that comes as no suprise. I never once got anywhere near full throttle on this thing and it screams!

Even as an inexperienced pilot I think I can safely say that the upraor (or dazzler) is a great conversion project for anyone. I would like to hear what the weight of the ARF version is. I tried to build this one light but it was mostly to the kit instructions with a few exceptions.

All I can say is I love this plane. I am going to convert a Tower Trainer ARF for my 8 year old son to cut his teeth on.

I am an e-believer now!

Riff

DMehalko

My Feedback: (42)

Sounds good, im gonna use the 28/26 motor though, and with props, if the plane is too fast go larger diameter and lower pitch. going to a 10x5 will only make it faster froma 12x6.

As for my uproar, i havent been working on it a whole lot lately, but will start back up once finished typing this.



Be back in a while!
David

RiffRaff

My Feedback: (16)

Okay,

Thanks for the prop advice! Like I said, I am new to this stuff. The problem I have is the ground clearance of the uproar. I have 2.5" wheels and the supplied gear wire/rod and 11" seems to be about it unless I change the gear/wheel config.

I am somewhat confused. If I run a 10x5 shouldn’t I slow down over thee 11x6 or 12x6 I have run already? The pitch is 1" less. I figured smaller pitch would slow me down and smaller diameter would increase run time (and same me some broken props, Doh!)

I may have to raise her up a bit and run like a 13x4 or something.

Still learning but your advice is well received!


Riff

DMehalko

My Feedback: (42)

But the smaller diameter will speed up the rpm's. So you would be correct with the 13x4, personally, my favorite funfly prop for 40 size planes is the APC 12.25x3.75

RiffRaff

My Feedback: (16)

I tried a 10x5 and a 10x8 last night. The 10x5 did slow the plane down but performance was very lackluster. The 10x8 increased performance some but it was no where near the 11x6 or 12x? that I had previously run. This setup demands at least an 11" prop I guess. I need to either put larger wheels on her or bend a new taller LG. I think the weight add or either option is going to be a wash so I guess I will slap some 3.5: wheels on her for sake of ease and up to the 11 or 12" prop tonight provided the wind stays reasonable. I have not officially timed any of the flights yet as I am doing a lot of tweaking at this point and the winds have been fairly high.

Riff