Frank Skilbeck

The reason the 400's struggle on a 3s lipo is that the volts are typically higher than a good old 6 or even 8 cell Nicad, so the 400 will spin a lot faster, the power drawn on a given prop is roughly the square of the speed, i.e. twice the speed 4 x the power, so if you doubled the voltage then the amps would also double. If you put a smaller prop on then the motor will still spin faster but need less power to spin the prop at this speed so the amps will come down. Beware of reducing the WOT setting in the travel adjust on the Tx, some ESC's autosense where full throttle is so dialing it down this way might result in the ESC setting 100% when throttle is at 40%. You'd be far better just throttling back when in flight, you then have the option of overpower for brief durations if required. I've got a twinstar running on the original 400's with a 3s lipo and use full power for take off on the UC I've fitted and then throttle back. The motors may burn out eventually and then I'll replace them with some the new brushed lipo specific 400's that Puffin Models are stocking.  One thing to watch if you are running the Grunther push on props is that the extra power can cause them to come loose and fly off , I had to put some proper prop adaptors on mine. Next I'm off to try my Twin Jet on 3s on it's 480 motors, should be fun. 

Nice sets, but why have the display under the neck strap which makes it more difficult to read. Also it looks like the neck strap is positioned for a long 35 aerial to balance not the short 2.4 aerial. The Spektrum DX6i addressed this by putting the neck strap clip below the on off switch surely this wouldn't have been too difficult on these top end sets. Maybe the futaba still has the 35 aerial so you can get the set to balance

OK I wasn't sure why you were disconnecting the red wire if you though the ESC didn't have a BEC. I agree it's probably best to use a separate Rx battery  than a regular BEC, the new ESC I've just got uses a switching BEC which can drive a full compliment of servo's.

My turn please

Coming out red hot is probably part of the answer. I haven't measured how many cycles i get out of my cells, but I put a 1400 mah 3s in a plane which normally used a 1800 mah 3s (both 12c I think) and the 1400mah was ruined pretty quick. I'm running some 1500 mah cells (3s) in my EDF but it's only about 200w and the cells come out warm not hot, I have not noticed any significant deterioration to date but I'm probably only running them at 12C or less. 

Timbo, I've just got a Turnigy 60A ESC with a built in SBEC rated for 3A continuous, 5A peek. I think Turnigy and Tower Pro are just rebadged versions of the same. If i understand Dave correctly he might have an ESC with BEC and has disconnected this to use a separate battery. The problem with then using the programming card is that the BEC probably provides the power to the control electonics in the ESC and programming card, with an OPTO ESC the power for the control electronics probably comes from the Rx battery. So if the red wire is disconnected then there is no power from the BEC to the programming card. Dave I didn't understand your comment about the other servos and Rx when you were using the programming card, to program my ESC I have to unplug it from the Rx and plug it into the programming card.

A 3200 kv motor is a very high rpm motor for use with a prop unless used with a gearbox. What size prop was supplied.

Dave, just a thought your ESC has a BEC and will use the BEC to power the programming card when you connect it to the ESC, if you've disconnected the red wire then it won't  power the programming card. I have a Turnigy one which I think is the same as the Tower pro type and it does have provision a separate power supply if you are using an Opto ESC. But maybe to program the ESC with BEC the ESC has to power the programming card, have you tried reconnecting the red wire when you are using the programming card. Note as Timbo says though the lipo setting won't affect the max power sent to the motor just the low voltage cut off  point.

To get 700 watts from a 4s battery you will be pulling over 47 amps, thats about 13c on your existing battery so shouldn't be a problem. But you would only get 4.6 mins at wide open throttle so allowing for flying at less than full throttle you would need to set your timer for less than 7 mins. I would think 2 x 3s batteries you mention above would be a better way to go with this plane, 700 watts on a 6s is going to be around 32 amps which is kinder on your batteries and gives a decent flight time, well over 10 mins.  I've got one of these https://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=2099&Product_Name=TR_42-50A_700kv_Brushless_Outrunner_/_720W Gives 8900 rpm on a 13 x 6 at 36 amps on a 4s battery, about 550 watts, you could probably put a slightly larger prop on it and draw a bit more current.

I ran a 370kv motor through drive calc using a 16 x 10 prop and it gave these results 4S - 23A, 4700 rpm, 2029g static thrust 6S - 45A, 6550 rpm, 3949g static thrust  So looks like you need a 6S battery (or 2 x 3S in series) and your ESC would be fine. Note I substiuted your  motor for a similar one as the Thumper motor was not in the data base. If you went to 8S you might have to prop down, say 16 x 8

I think the fleet plugs were pretty specific to fleet, I can't remember anybody else using them. The batteries in the TX are not on a plug but are soldered directly in, well they are on the two sets I've got. Can't you reuse the leads off your existing RX battery. 

The "batteries" or ultra capacitors you describe might not be 30 years away http://www.technologyreview.com/Devices/wtr_16326,303,p1.html?a=f

If you are just a relative beginner the small park flyer low wing types might not be all that great as orientation can be a problem and they get small very quickly, probably best for after you've had one low wing plane under belt, and then I'd recommend one of the Alfa warbirds. But for now you might want to consider something like a Multiplex Minimag http://www.modelspot.com/mpx/minimag.htm

"Incidentally I thought it remiss of Spektrum to go on and on about the charger plug polarity, but not mention that a std Tx charger is the wrong voltage!" Good point but then again my 35 Tx is a Multiplex with a 6 cell battery so I never use a standard Tx charger

I thnk people mean Nitromethane, methane is what British Gas send to your house for your heating system

My LMS doesn't stock 35 mhz sets anymore, but does have 35 Rx's in stock. I have both a 2.4 and 35 and can't see me buying any further 35 gear, but then again my Tx is less than 12 months old and I have 7 or 8 35 Rx's. 2.4 is a boon in small electrics.

The battery box in my DX6i seems very secure, I think if I was to take it out and fit a welded pack I'd have more concerns over my modifications than the original battery box.

I have a Jeti ESC in the fuselage on my Alfa Mig with no cooling air, has done over 50 flights with no problems. Also have a ESC inside my Fantom and Twin Star (brushed), again no problems.

Timbo, thanks I'd rather use some high quality rechargables than poundshop dry cells. I would be quite happy fitting a welded pack into the Tx but I'm not sure how that would affect the warranty of the equipment. I must admit that the battery box supplied seems of good quality and the batteries are very secure. In the instructions Spetrum state that the DX6i sold separately is normally supplied with rechargable NiMH batteries and overnight charger but when sold as part of a RTF set will come with dry cells. It looks like in the UK they decided not to ship with rechargables and charger (maybe to meet the magic < £100 mark). They state in the manual that optional NiCd or NiMH 1.2 volt AA cells can also be used and then go to great lengths to warn you of the polarity of the charging jack which is different to say futaba. There are no instructions on fitting a welded pack into the Tx, maybe that could be a technical article in RCME in conjunction with Spektrum. Ironically I'm only using this set in my small electrics at present and I'm using my 35 set in my larger glow and electric planes. 

Timbo but the BMFA handbook says that it's OK to use dry cells in the TX and these don't usually come in welded packs. The Spektrum manual says it's OK to replace the dry cells with NiCd's of NiMh's. Will using the Tx set with non-welded NiMh's invalidate the BMFA insurance, will Horizon Hobbies be responsible in that event as it's included in their manual? Should RCME be issuing a warning advising people not to fit loose rechargable cells in the DX6i's but continue to use dry cells as advocated by the BMFA?  

John Mne came back with two free servos to componsate for the postage (£12.60 to Germany),  I understood that the problem was sudden lose of the Tx, so if your problems were that your failsafe (i'm assuming you were using IPD Rx's) cut in that might be a possibility. But if the Tx carried on working then it may have been interference or something else. Note my Tx had been fine but i sent it off as a precaution.  I also understood that the problem was most apparent in hot humid conditions but MPX decided to recall all sets that could be affected. 

Note the batteries in question are in the Tx not the Rx. Lots of RTF which include the TX use individual cells.

I have a 4 cell balance which comes with a JST EHR connector, to charge up my 3s JST XH batteries, I have a 4 to 3 JST EHR adaptor and then a JST EHR to JST XH adaptor, to balance my flight power battery I then have a JST XH to FP adaptor. I've just got soem 4s JST XH cells and I'm now looking for a 4s JST EHR ro JST XH adaptor, but as most of my batteries are JST XH I mnight just get another charger with JST XH balancer ports. It's a real pain in the neck. 

Note my SX was returned from Germany in just over a week, so not a bad turnaround. 2 nano servos included for the inconvienience and latest software (v1.10) also installed.