I have a sm f18e, on my third flight i lost radio. (locked out) for five seconds. I have a jr 945 rec. 10x radio, two switches, two jr 2700 mah. nick metal batt. I was told the jr8711 are to much for the rec. I have 2 on elev. 2 on flaps. PLEASE HELP. THANKS ROBERT BERNAL

Do you know if it went into failsafe...ie did turbine shutdown?

Marty

robert, the article we spoke of at cleveland is on bvm's front page. scroll down, it is the article about new technology and new products and how to integrate them. good luck, barry

No the turbine stayed at the same setting, fail safe come to find out was not set. Its been properly set since that time. Im glad, I still have my jet. but to scared to fly. I also sent rec.& crystal to jr and they found no problems. I get 500ft with ant. down and 300ft with ant. off. turb. running and jet at any angle .

Loss of signal for five seconds and you still have the plane? Very lucky indeed. You should check the plane with this http://www.horizonhobby.com/Products...?ProdID=HAN172. Hook up your batteries and RX with no servos connected and notate your voltage and then add one servo at a time. Exercise each control surface to it's fullest programmed throw and note how much current you are pulling. Check each one seperately and see if any one looks to be pulling more than the others and then start connecting all of the servos and see where you end up. Since digital servos always sound like they're straining, it's difficult to tell when they actaully are. Hope this helps.

OK, the link doesn't work. Just go to Horizons' site and type in current meter in the search box.

Marty

Did you check with Horizon's tech dept ??

I think Marty is refering to this. http://dreamworksrc.com/catalog/prod...roducts_id=278

Rgs
Alejandro

Did this happen when the flaps were lowered?
Scott

Yeah, that's it. Thanks Alejandro. I use an Astroflight Whattmeter which does pretty much the same thing. Definetely an extremely useful tool when setting up your planes.

Marty

No, flaps were up, plane just came out of a hi bank turn. I was in level flight.

4 cell or 5 cell Nihms?

B

Per what you have observed during your range checks the R/F link sounds good.

I would look to a high current drain / low voltage situation... could be the type of battery. NiCads are better at supplying high current when needed. High C rated Lithium batteries will also do the job, the problem with lithium’s are in regulating the higher voltage and not over loading the regulators.
Lee H. DeMary
AMA 36099

Hey Guys. Im using two 6 volt jr nickle metal 2700mha, with two switches jr heavy duty. THANKS ROBERT

Robert,

I'm no expert but that sounds like plenty of battery power to me. I'm running a single 5 cell nicad (3000 mah), regulator and JR HD switch in both of mine with Hitec digitals all around. It seems to me that the Hitecs like a lot of battery power, but I have had no issues.

Maybe someone else turned on a TX for 5 sec. That possibility has always scared me at Scobee.

Wait....Bob. what is the impedence on those 2700's? THere were some high impedence sanyos out at first and they could not handle the load. They were released as transmitter pack batteries. I almost made that mistake, and Dave Thacker at Radical RC caught it. Call him if you need to. What triggered this thought is that you came out of a high G turn? I am not experienced with jets, but we are seeing issues on other GS guys with batteries that cannot handle the load of the big servos when they are all strained, and the receivers are getting dropout.

I dont know if you heard or not, the A123 M1 batteries are catching on as Receiver packs too. Unregulated 6.6 volts for 2S1P 2300, good for 60C or something amazing like that. recharge in 15 minutes. I am switching my prop planes over. Again, I dont say I know anything about the jets, but your symptoms sound familiar to me. There are good articles about on getting low impedence packs for these big servos. I suppose thats why Nicads are still in vogue for high current demands.

Hope that helps.

OK I have been working on the jet most of the day. I got a hanger 9 amp-volt meter. My jr 2700 6v. are not suffient. Me & my son put loads on the plane with both batt. on a y. We got the voltage to drop to 4.0 volts at the rec. The batt were fully charge and were condition at first chaged, and there only 3 month old. I use this batt on my big birds, buy i use duel rec. Any advise on power supply would be help full. I have no room for power expanders . or another rec. I like simple, I think volt reg. can add ploblems. Thanks For the help guys, Its my first jet.

On another note, if we find strong enough batt. is the jr 945 able to handle the load. We pulled 5.8 amps. on the bench by putting presure on the surfaces. So i think it would be greater in fligt. 7 to 8 amps ?

put 8611's in. i have never had any issues with them in my f84. it runs 8 of them on 2 6v 2400 nicads. good luck, barry

Get a couple of 5 cell 2400 nicad using a couple of switches. That should do the trick.

Also check your extension cords. The JR Heavy duty are 22 ga, I went with 20 ga on my F-16 to help reduce the voltage drop. Also, you should use heavy duty wire from your battery to the switch to the reciever.
BRG,
Jon

Hi Berry. Ni Cads put out much more power, I just found this out today. I think thats why it works for you. I took amp. readings on both 8611a & 8711 not much diff. I think my ploblem lies on low quality batt. This plane has alot more servos than my big birds. Im glad i asked you about my ploblem at cleveland, It problably saved my plane. Thanks

HI JON Yes I put volt meter on both ends, only found .2 volts across leads & swiches. thanks STILL NEED HELP ON POWER (BATT) what type and size, and can the recv. handle the load.

Bob,
I have used NoBS batteries and find them to be very good quality and Steve gives the impedance rating of all the different packs and their applications. You can also give him a call and he will suggest the best packs for your particular application. His prices are pretty reasonable too. Check them out.

http://www.hangtimes.com/index.html

Marty

I aked a similar question on the Jet List regarding power supplies for my F-16, Here's Bob's reply:

"I tend to be VERY conservative about servo power supplies. Whatever it
is, it needs to handle a burst of ALL servos simultaneously at stall
current. The reason is that every time a servo starts moving or
reverses direction, its going to momentarily be at stall current. I
have never tested the new JR high torque servos but the older 8411 could
go over 2 Amps. Since output power is not free, I would suspect that
the 8711 might go higher than that.

Like I said, I am conservative about such things.. and I think its hard
to beat a big NiCad pack. Simple, lots of current output capability etc.

As Larry mentioned, wire is an issue too. You need good switches, and
heavy gauge wire. I have been known to use 16 gauge from the battery,
through the switch to the RX. And realize that the RX board may only
handle 5 to 10 A on the power bus."

BRG,
Jon

Just like you, I found out the hard way NIMH's have not been kind to me. I have now RELIGIOUSLY dumped all of my NIMH's. I have two left that I use for the smoke systems in my jets, ie not a critical, high draw component. Once these two are dead, I will completely leave them for my surface R/C systems.

FACT: NIMH can not handle sustained high current draws. (anything bigger than 2 amps and I'm tapping out)

FACT: NICD's can. Lipo's can too. I forget where I read this, but the JR RX can handle 10 amps.

I run just a single 2400 NICAD to power all of my multiple 8611a jets. My SBB had 8 8611's and my KC has 6 8611's. I check batteries before EVERY flight. I have an onboard checker so I can check with a load. I charge at every 2-3 flights. Cycle once/month.

Raf