Electric TF Nobler

Guys,

I have been following the electric development and would like to try. However I have purchased the TF Nobler (almost a year ago) and would like to electrify it.

The recommended weight of the nobler is between 42oz and 50oz, with 500 sq inch of wing area, the WL loading is between 12.1 oz/sqft to 14.4 oz/sqft.

Is being the lightest absolutely necessary in CL stunt?

The Axi / battery combo used in the genesis is abt 20 oz in all up total weight. If I was to use that combo in the Nobler the flying weight would be in the region of 52 - 54oz translating into WL of between 14.9oz/sqft and 15.6oz/sqft. I understand that it will slow down in the turns with the heavier wing laoding.

Is Average of 150watts per pound is enuff to perform the entire CL pattern schedule or a minimum of 170 watts is needed?

Thanks in advance.

Frank Carlisle
proud member of R.C.C.D.

Marcus,

If you're looking to get a world beater stunter out of that ARF Nobler or if you think that by electrifying it you're going to make huge improvements on your pattern then you're in for a huge disappointment. IT IS NOT GOING TO DO EITHER OF THOSE THINGS. And it isn't magic.

Unfortunately, many of the cool classic designs have wings that are small for electric power right now. Battery technology has improved a lot over the twenty years I've been playing with electric power and I expect we will see even more improvements.

Because it was the first CL ARF and the guys at TF adapted a lot of RC technology, the Nobler ARF is overbuilt in certain areas. You can help yourself by grinding out as much of the motor crutch area as possible. Also grinding away that bolt on wing stuff and anything else that doesn't look like a control line airplane will help. IIRC, the Nobler ARF also used spruce sub spars in the wing center section and plywood wing tips. All strong, but heavy.

It's still going to come out heavier than a regular Nobler and will not perform as well. But it will be quieter and cleaner and it could teach you a lot about electrics for your next great project.

150 watts per pound should be fine. More is always better if you can effectively control it.

Take care,

Ron King

Frank Carlisle
proud member of R.C.C.D.

If you use a spiral saw blade like the ones that come with the roto zip tool you can cut out all the bulkheads in the nose and pry off the hardwood motor beares too.
Create rails to slide/rest the battery on using a light fairly hard wood. Paintsticks work great for this.
I think the plastic cowling may get in the way of sliding the battery in and out of the plane for charging, but I'm sure that can be gotten around.
While the model won't be a world beater- you'll have loads of fun with it and you'll have taken your first step toward this new technology.

Just a few thoughts on electtric flight;

Your ARF NOBLER wil fly just fine with the axi 2826/10 and a 4cell 4000 mAmp li-pol
I have an article on a similar setum but using a Mega motor. The axi has a little more
power. It will draw over 500 watts swinging a 10/6 or 11.5.5 prop - measured at the battery static. To do 5.0 to 5.3 sec lap times on 60 to 62 ft lines eye to eye, the Nobler will draw about 275 watts of power for level flight using an 11/6 APC electric prop, measured at the battery ( so actually less at the prop), It will draw 18-20 amps, and the voltage will drop a little from about 14 volts to 13.75 by the end of the pattern. The flight will pull about 2100mApms out of the battery which is just a little more than one half of its power. I know this because I measured it using an Eagle Tree System on board data recorder. I'll be pulishing an article about it in the next Stunt News. I've been flying an ARF nobler to two first place Classic events, two years in a row at the Wrentham MA meets, 2004, 2005.
So if anyone says it is not competative, think again.

I've got a Gieseke Nobler electric for this year's events. It weighs about the same - 42 oz without battery, and about 53 with it. So what, it will fly competatively. It seems that the ARF Nobler from top flight can carry some weight, and the Gieseke Nobler has a slightly thicker airfoil and seems to carry the weight as well.

Mount the battery right against the underside of the wing, allowing back and forward movement to adjust cg.

Go have so me fun. If you have additional questions, contact me @

[email protected]

The Axi 28 series motors and 4300 mah batteries are a bit much for a Nobler. That is pretty much the equivalent of a good 40, and the same weight. You'll have to shop around for a smaller, lighter motor and battery to match to keep the weight down around 45 oz. Plus Frank's suggestions on lightening the plane up.

Just a few thoughts;

The axi setup with a 4000 mAmp 4 cell li-pol will be more power than you need, but the buffer is handy to have. Going down in motor and battery size may save you a few oz., but may be borderline for reserve power. You want sufficient battery left after the pattern so as not to loose too much voltage and hence power by the end of the flight. Going down in motor size may save an oz or two, but the additional power of the axi comes into play during manuevers. I use a three speed count down timer so that I can kick it up a little @ the square eight and beyond to compensate for slight voltage drop.

The setup, using a 10/6 to 11/5.5 prop will develope more that 500 watts at the battery, at full throttle. If you are using 60 to 62 ft lines eye to eye, and adjust your timer to produce lap speeds of 5.0 to 5.3 sec., the system will draw about 275 watts during level flight ( measured at the battery, less at the prop due to efficiency losses) and about 18-20 amps, which is good because that low amp draw will keep everything cool. Amperage equals heat. I try to design systems that do not draw more than 30 amps at any time during the flight to keep heat under control. If you start getting close to 30 amps, go up in voltage do drop it down. Voltage times Amperage equals Watts. Maneuvers will draw up to 310 watts as the motor senses load . For a 6.5 minute flight, you will use up about 2100 mAmps of the battery's power - about half , which is good - both for the battery and for the flight.

I know all of this because I have been doing measurements on my Noblers, using an Eagle Tree Systems on board data recorder, and downloaded on my computer for overview.
I'll be publishing an article about it in the next Stunt News.

My ARF Nobler flies just fine, even though it weighs about 54 oz. It did well enough to place 1st in Classic 2 years in a row at Wrentham, MA, 2004, 2005. So anyone who says it cannot be competative, think again.

I have a Gieseke Nobler, scratch built, that weighs 42 oz w/o battery, and about 52 with it. I plan to fly it this year in Classic. Interestingly it does not fly quite as good ( or maybe just different) than my ARF, but it should be OK.

Mount your battery right on top of the bottom of the wing, holding it in with velcro straps, allowing adjustment back and forth for CG.

You'll have a blast.

It you need to speak to me more, or have questions, go to

wmflyelectric @verizon.net

LAST EDITED ON May-12-06 AT 06:03 AM (CST)
 
Guys,

thanks for the replys..

I am not into competition, its just for personal satisfaction and fun!! Im a beginner CL'er anyway....I'd like to go electric to keep it 'clean' and also since I have the TF Nobler at hand, the idea of converting it was natural.

I'll try the axi combo. Since for 6.5 minutes the system uses only 2100 mah, I'd probly get a lighter battery, say maybe the 3200 (20C)..this will then help reduce weight. Lightening the fuselage is also a good idea.

I have an RC 3D plane, Funstar to convert to CL...it has 740sq in wing area and all up CL flying weight of 3.5 lbs. Here is a link to it

http://www.towerhobbies.com/products/pmm/pmma0335.html

I'll probly put lights in it for night flying!!

anyone has an estimate of the thrust to weight ratio of a CL stunt plane?

Thanks again.

Frank Carlisle
proud member of R.C.C.D.

Maarcus,
I believe you should not drop below a 3700 mah battery. The draw on the 3200 will probably be too much and seriously reduce it's service life.

frank,

looking at it from a technical point, a 3200 mah at 20C is capable of providing 62A of discharge current, however the maximum current the system is deriving is about 30A - 35A only, ie 57% !! The new cells should be able to last a lot of cycles if only 57% performance is expected from them!

So, I am deducing that the only reason to go above 3200 would be to get more flight time from per charge.

Enlighten me...

Frank Carlisle
proud member of R.C.C.D.

O.K. Marcus. Sounds good to me.

I DO have my electric Smoothie and even though I got it to work and am having fun with it, I must relay to you that I really don't know much about this electric business at all.

My current plan is to play with the Smoothie off and on during the summer and build a dedicated electric plane to put my motor in this winter.
If by then someone produces and sells a new/better battery or motor or timer I'll get that. I'm not going to be able to make any innovations on this and will wait till one of the other guys does.

So you are correct not to take what I have to say as word from an expert.

Frank,

this is what makes the whole 'thing' excting !! its 12:30am here and I have access to the net, hence making every oppurtunity to read and digest then formulate my 'way' forward.

I am not disputing your 'expertise' in any way, i belive that IF we are not challenged we will NOT progress and progress is what we want in CL electrics, loads of it!!

What setup do you have in your smoothie? wing area? weight? prop? rpm? does it perform 'well' on the completer F2B schedule? would love to hear furhter from you.

LAST EDITED ON May-14-06 AT 02:48 AM (CST)
 
I think I know what set this off. It was wiping all that oil off the Bislob last weekend. He put a Fox .35 Stunt in it. As per instructions, we mixed up some 29% oil fuel (though I think, in the end, it actually had more like 31% oil in it) and after a looooong break in, he mounted it in the plane and we put up a couple flights. It was like someone had filled a 2 oz. syringe full of oil and squirted it all over the outboard wings and fuselage... He had to put some newspapers down in the car before putting the airplane in it because the rest of us wanted to drive off to watch the beginning of the F1 race...

Isky,

you let the cat out of the bag !! Anyway, I am beginning to think that elctric is getting stronger by the day, its a natural progression for me...we'll see how it goes.

Get in touch with Will Moore - he has built and very successfuly flown an ARF Nobler on electrics.
[email protected]

Regards,
Dave Cook