Futaba JR?

On 24 May 2007 05:47:46 -0700, snipped-for-privacy@chaosmail.com wrote in :

He should have done a better bench test to find out what was wrong with his throttle setting and/or installation.

The signal that comes OUT of receivers is pretty much plain-vanilla and industry standards. The ESC shouldn't have any way of figuring out whether one brand or the other is driving the RX.

Don't kick him while he's down. Go over to his house and hold the plane while he jockeys the throttle and debugs the system. ;o)

Marty

Marty,

I am already 140 miles away. But I have been to his house many times. It's just that I'm concerned that he may give up on his hobby altogether.

However, the questions I asked may be moot, as a fellow flier has determined it was the 3S3P Li Poly batteries. He checked and the batteries were over due for replacement. They won't hold a charge. That may be why the motor cuts out at full throttle.

Which brings another question. I had not used the batteries I gave my friend for over a year. I have 3S1P Li Polies and they have not been in used for about a year and they still have more than 12 V in them.

Why didn't the 3S3P Li Poly hold a charge?

Wan

On 24 May 2007 12:47:04 -0700, snipped-for-privacy@chaosmail.com wrote in :

OK. It does happen. :o(

Ah. Makes sense. If the voltage falls too low, the ESC may cut power to the engine, I imagine.

Beats me. Someone else may have a theory.

Marty

Cos they were crap to star with possibly.

I dont run with LVCs and I took a new pack of 3x 2200 "15C" cells from a 'chinese source' and tossed up my picojet. It came back to earth. I flung it harder and it staggered into the air.. just..with about the same dead duck performance as on the 8x1300CP pack it used to have.

I thought the motor had gone, but when I tried the same (brand new) pack on another model on a whattmeter, it read 8.4v at 12A.

messagenews: snipped-for-privacy@news.supernews.com...

Fubar of The HillPeople View profile More options May 24, 8:58 pm It might show 12v but under a load will probably show something entirely different. Probably has a bad cell. My father went thru that recently with a pack. Showed fully charged on the charger but at the field the plane seemed to have only half the oomph it used to. Further analysis id'd a bad cell. I would toss em and buy new.

If you're talking about one of my 3S1P battery. I used same to check and test four of my small planes. The battery measured about 12.4V afterwards. That same battery has been in storage for about one year.

Sort of makes one wonder, Wan

If you don't keep at least 2.8V per cell in a lipo for storage, they will go bad.

Hi Wan, Are you saying that the batteries were in storage for over a year and your friend used them without charging? If that's so, the BEC was doing it's job and shut down the motor. Your friend should have placed the throttle in idle to reset the BEC and then added just enough power to make the field and land. Lipos will self discharge (even when stored properly) at about 5% per month so your batteries were seriously in need of a charge. Your friend may be able to bring them back with a good Lipo charger and a cell balancer. The results would have been the same had he used a Futaba or any other brand transmitter. If this minor incident discourages your friend and he decides to give up the hobby, encourage him to do so. Take back your birds and give them to me. I'll give then the care they deserve! ;-))

As others have indicated checking a battery with a voltmeter and no load is as useless as altitude above and runway behind you! *Totally* useless.! With no load all you're getting is a "float" reading. To provide useful info batteries must always be checked under a suitable load.

Jean Rondot aka J_R who used to frequent this forum lost his two-year battle with cancer on 5/24/07 with his wife at his side. Jean and I were best friends in junior high and high school and maintained contact over the years. His love of modeling began early and at fourteen he was cutting his own design U-control kit for the LHS to help pay for his hobby.

I'm not sure what other forums he frequented so thought this would let folks know. Moderator: please move it if you see fit. I have no further information at this time.

Steve Kerrin

My condolences Red. Seems that the older we get the more friends we lose - It's not fair :-(

Hi Ed,

Good to hear from you. My friend is easily discouraged and had sworn off of model airplanes many times, but building and flying is his life. He always comes back to the "fold" He did recharge the Li poly before taking it to the field. But as i've said, the battery would not hold a charge.

He had called me when I have moved with many quesions for electric planes. My cocern is for him leaving electric because he has a problem with his hearing around the noise of gas powered planes.

I felt badly about the lost of another model flier as reported by Red.

Wan

Oh crud. I hurts to loose a friend...

All our best wishes and condolences to his family. I am sure he will be missed by all.