Jim Patrick

So I was helping a club member on Friday. His 5 kw electric was having problems. When he hit full throttle, funny noises.
He puts Watts up on the plane and is getting over current.
Now this was with new 30c Thunder Powers, 12s. He is wondering why this could happen.
I told him to check again, this time check voltage.
With the new batteries, was getting 5 more volts at full throttle than on older EVO 25c 12s.

NOW he understands....................

marm

My Feedback: (1)

Currently, no small fan can hit those kind of watts and stay together.


Course they could, but why! If a cat diesel does 400 hp and 1600 pounds of torque and can haul grain like no tomorrow, is that the motor I need for my Nova? And if they say hey the new turbo for it is so massive it'll blow up a 350 engine, that mean i still have the wrong engine in my Nova. Cause a guy standing next to me on the surfaqce could be dead right in saying hey! That CAT has more power so its gotta be better. and he could also say hey! the same fuel tank could be filled to run it with no added weight. But then we would be ignoring physical world where more power means you need more of something to fuel it. So given I have an ideal combo in my Nova if I drop weight cause any added power might add weight is that a short coming of my smaller motor that its perfectly suited for my power to weight.


Barry

marm

My Feedback: (1)

High rpm is generally less efficient in spinning rotors because double the velocity=four times the drag, and high rpm means the rotor has to be made a lot stronger (thicker) because double the rpm=four times the centrifugal load amongst other things. As an example, a fan designed to operate at low rpm might produce 350 km/h efflux and 7 kg thrust at 25000 rpm and 3500 W, and a fan designed for high rpm might do the same at 50000 rpm also at 3500 W.


well thats only true if you change nothing and just spin a same foil at higher or lower speeds. if the fan is designed for its raqnge it is altered accordingly. If you look for example you will see a DS-94 has the same 78% efficiency as a DS-51 despite the big RPM difference. And as example the TF4000 which spins slower then both of those actually has a about %7 less efficiency than both of them. Then even slower still the Vio fan has about %25-%30 less efficiency than all of them. And if you look at loads they also ramp in accordance with static efficiency so the highest loading fans we happen to have at our disposal happen to be also least efficient. and so we see regardless of RPM bernouli is still dead on with the shortes run time going to the fan with highest loads regardless of RPM.

Barry

Shaun Evans

Barry,

If I ever direct a production of "The Music Man", you have first right-of-refusal on the part of "Harold Hill."

What ever happened with that F-16 you were building? Rememberthe one you showed a progress photo of (with the caption, '...boy, this is going together faster than I thought...') but upon inspection it turned out to be a pic taken years before of a turbine one?

I mean this in the best possible way, but when I read your posts on the subject of EDF, somehow I feel no closer to facts or reality. WHAT ARE YOU TALKING ABOUT???

Kriptonic69

My Feedback: (1)

Post a video of the run up showing the amp meter please. Also add an uncut flight video if you could please.

k_sonn

My Feedback: (32)

Funny, Tam posts numbers of his setup and you nor anyone else hasn't asked for proof but that's ok, I don't have anything to hide nor am I abusing the site by trying to get free advertisment to sell product. No video of the run but here's a screen shot of the numbers at about 45 seconds into the run when I went to full throttle. This is exactly the same setup that was in my Starfire last year with the exception of a new ESC and the TP batteries. Over last year's setup, I've gained 2 ounces in weight and about 2000 watts of power. My fan/motor/controller combo can handle this kind of power with no problems. The only issue I've seen with this setup is I've blown the thrust tube apart, all that fast moving air trying to get out had to go somewhere. My watt/weight ratio works out to 450watts per pound. Also, if you do the math you will see the batteries are holding 3.69 volts per cell under that kind of load. Those batteries are for real.

Last year at the end of E-Jets Tam ran off at the mouth stating he was going to build a Starfire and put his fan in it and he would run circles around my Starfire. Tam, all I ask is that you to bring your Starfire to E-Jets and try to make good on your words, pleeease

acw

My Feedback: (1)

Could we stop this silly message board war? We are talking about electric model airplanes! I hope Tam continues to keep us updated on latest electric development. I also hope that others will do the same.

Arnaud

Reverend Russ

Are you actually proud of your jets needing 6.5 kw to fly well? How embarassing...heck, since your big block fans are so powerfull why don't you pull a trailer with your jet for extra cells so you can go for 9kw. You're a genius!

Avaiojet

For a guy that's considering EDF, I'm trying to determine what I can digest and learn from this thread?

Photo of the DF unite would be nice for starters? Measurements? Available from who?

Wingspan, wing area plus loading would be nice also.

I'm picking up bits and pieces of information about EDF from Threads, Threads like this, but no real conclusions. Seams like the information is in code. Gotta learn the joggin.

I have a scratch built C-101 I started years ago, like 25 or more. set up for a Rossi prop. 56" long and the span could be between 46" and 50". I'm working on that. I may need the squares.

Anyway, I redrew the planes. or at least the areas that require change. I'll change the model for either EDF or Turbine. I prefer EDF, at least then I don't have to be concerned with burning something down.

I did start a few Threads with photos asking for information.

Any of you guys seen them?

This is the model in prop form. The nose will change and improve the look tremendously.

I'll get a photo of the plans I just changed. The model really isn't a bad beginning.

Sorry if I'm walking all over this Thread, but this is where you knowlegable guys are.

Charles

k_sonn

My Feedback: (32)

These kinds of post start when someone thnks they're at the top and they suddenly find out they aren't even close.

Hey Russ, for the record, it's not a matter of "need", it's a matter of "because I can" It's no different than the many times you've stuffed an oversize turbine into an airframe.

k_sonn

My Feedback: (32)

Here's another reason why you and Tam are so hostile. You all haven't been around EDFs long enough to know there is a technology growth cycle. Those of us who have been around EDFs for awhile know and understand the growth cycle and we put our equipment together in order to take advantage of the growth cycle. Let's face it, in order for the TJ100 to utilize the 40C batteries (the latest outcome of the growth cycle) one of two things have to happen. 1. The cell count has to drecrease in order to mantain the same power level of the less powerful batteries the system was built around. Sure, there would be a minimal weight savings but it would never equal to the amount of increase in power absorption of the 120mm fans. 2. Replace the motor and controller in order to handle the amp increase of the 40C cells. This would add weight and would go against the "lighter is better" phylosophy. And, the fan would have to be able to absorb the rpm increase without blowing up. On the other hand, the TF4000/1527 combo can absorb the power increase for virtually no weight gain. The EVF has also proven it can absorb the power increase of the 40C cells. E-Jets is going to be fun this year

rcjet lynch

I say we take this show to Jerry Springer.

uncljoe

My Feedback: (8)

Charles
IMO For the answers to your quest go to www.RC Groups when there page down to electric jets . You won't run into too many shills who are hawking their benefactors wears.
Semper Fi
Joe

Kriptonic69

My Feedback: (1)

142 amps [X(][:@].... Are you trying to weld something? why don't you run a dead short across the batteries . I wonder if you can keep that 142 amps continuous for that 6 & 1/2 minutes on that 6500mah pack? Hum....??? Also when does the motor start to demag? (you don't have to answer that, it's a rhetorical question).

Remember Folks... Voltage Is Your Friend.

tamjets

My Feedback: (2)

Joe and Kirk.
When you talking about shills. You guys made a few negative comment about flight time, noise, rpm and pilot. But not single post said anything good about it. That is O,K. I know whom you shills for.
Russ respond to your comment with fact and data.
You call him Tamjets shills.... what is that all about.
You need to look at yourself if you are at right first. Don't assume that you been around here for so long and do had a lot friends on this forum give you that right said things to get away with it.

This thread start out isTJ100 flying Skymaster F-86.
All your post (almost) so far had nothing to do with this thread.
When you guys said I did free advertisement on this forum.
I remember correctly I do sponsor this site for many years.
I don't thinks one post once awhile is abusing this site. There is someone on here abuse this site for years is not putting out a penny. Why don't you go get him. He is here taking a ride along with you guys.

Matter of fact.
I didn't abuse this forum. You guys did. You guys had so much beef and eagle can't stand my works I had done. You had to find what ever reason to jump on this thread to give me crap. What had you guys done so far and had something to share to this thread? Nothing beside put up all the drama and play like you guys are good guys.
I remember first few days I post this thread. Only few had said something nice. This thread stay very quiet until some had to bring it up and start the drama.
If you guys love to advertise for me.
I don't mind. Kept this thread hot.
I go get more popcorn and maybe finish all my green bottles.

smitty1001

My Feedback: (29)

Tam, flew the tigermeet 1:12th turbine prototype today on EDF. Your TJ100 & 8S. So much fun! I love the sound and flight characteristics. If Iwant to hear turbine, I have 2 of those, so Ijust start those up.

Soon Obama will only let us fly EDF because of carbon footprint of jet flyers anyways.... and California will have to take all money from Texas for Michael Jackson funeral and other IOU's. Right now, I'll just fly both EDF and turbine until they take away. Keep up the awesome work - your innovations have contributed so much to our hobby - between you and uncle bob - Idon't have pay check anymore! Luckily, child support is taken out of my paycheck before Ican give to you and BV.

btw...... Icould care less about all of those numbers - when Iplugmy batteries into your fan it works and goes real fast - thank you little man

tamjets

My Feedback: (2)

That is funny......just hope there is enough money to goes around.

Reverend Russ

You are absolutely right...I can't argue with you there. I guess I have done some crazy things and they were fun.
I think it is impressive to be able to throw that much power to your systems and i'm sure the power you get out of your 120mm fans are very high. No one can dismiss the shear thrust produced by the 120mm fans and in some applications I can see it would work well but at a cost of a lot of amp usage.
I know you don't care for the TJ100 and that is just fine. There are people who love a small block chevy and hate big blocks and some are big block fans, that is the beauty of different options. Just because someone likes a big block doesn't mean the big block is the best for every application. The TJ100 has proven to work reliably, strong and extremely efficient. With hundreds and hundreds of flights in airframes from 8 to 21 pounds with excellent results it is a proven power plant for many applications. It has done so well that it is compared to all the big blocks on the market and has held its own.

This thread is about Tam wanting to show off his new toy. If someone wants to stuff a big block in the skymaster F-86 then do so...this is a free country and I'm sure Skymaster USA would love for someone to order another kit as Tam did.

Russ

k_sonn

My Feedback: (32)

Agreed, that is the ideal setup but unfortunately that is not where the technology is heading. Where are the high voltage controllers? There are some really good high amp controllers from Germany. The new batteries are more capable of handling high amps. The Thunder Power 40C packs can handle a 256 amp draw, continuous. The larger Neu motors can handle the high amps also. Until reliable high voltage controllers hit the market, high amps is where the real power resides. If you want to fly the larger jets with any kind of authority (it's not all about the speed, it's also about the verticle), you have to step up to the high-power setups or you could always use a smaller fan and fly around like a gaint scale park flier edf.

k_sonn

My Feedback: (32)

Exactly because the TJ100 really is best suited for these small EDFs.

tamjets

My Feedback: (2)

Wow, that is sure show some beef right there.
This F-86 is smaller the F-16 I think.
I found this photo and I think should considered what it mean.

George

My Feedback: (57)

Tam,

Nice video of the F-86.

Are you doing anymore with the Bandit ARF in terms of development or are you done with that project. I want to do the conversion when I get home for good, but want to get the "latest & greatest" when it's time. I knew I wouldn't be around for awhile when I first talked to you about it, so that's why I didn't buy just in case a year later that something better was available and now I see that was a wise choice with new batteries coming out and whatever else.

So, any further development on that airframe or any plans for the future?

George

tamjets

My Feedback: (2)

George,
The Bandit pretty much done. I had the light gear and wheels set up for it. With the new 11s 40cc 5000mAh running the 1518 1.5Y motor. It can be done at least 2 pound lighter weight than before and still had the same power.
Here is the latest video from Esprit had done the Bandit with TJ100 with the new 40c cells. His set up still little heavy and it already perform this well. Just imagine another 1 pound lighter. You know how that goes.
http://www.youtube.com/watch?v=dqzNqVJ2SzY

Be safe over there and come home soon playing with model toys.


Here is a reference comparion the first bandit fly with old 25c 5000mAh.
Batteries do coming a long way since last year.
The performance show what a huge different.
http://www.rcuvideos.com/video/Bandi...-5000mAh-4-1kw

George

My Feedback: (57)

Pretty impressive Tam, thanks!

Looks like a good set-up. I got an extra Bandit laying around, so I'll be calling you when it's time.


Thanks & take care,
George

tamjets

My Feedback: (2)

Thanks,
Ralf Dvorak from Germany also did a nice job with his Balsa Bandit Electric conversion.
He is running DS-94 (120mm fan) with 5.3kw to 5.7kw.
Check out his flight.
http://www.rcline.tv/video/1519/el-b...on-ralf-dvorak