Piper Cub

Although I intend upgrading to 2.4Ghz radio when cash permits, I've never really got my head around the radio & digital servo combination. What's that all about? OK, I know digital servos (like everything else digital) are more precise and accurate ie whereas the 'old' analogue servos doesnt or wont return to the exact centre position after a command for left \ right etc, the digital servo will. But what type of radio (excluding the 2.4Ghz gear) do you need to get the advantages of digital servos? I've a Futaba FP6. Does this and other radios have to be used in PCM mode to take advantage of digital servos accuracy or, can digital servos be used in PPM mode?

Nice kit. Has this one got my name on it!?

Im in the process of charging & balancing my Lipo pack. Its a 3200mAh, 4S, 15 - 25C pack. I've set the charger up at 1C = 3200mAh, pack voltage 14.8. There is no facility to set individual cell voltage as the charger detects this automatically. The charger is a Mega Power Poseidon 860DS  The charger is showing a voltage reading of 16.875V during the charge and balancing cycle (instructions advise the charge leads and balancing lead are connected at the same time). Is 16.875v ok for a 14.8v pack?

The D Peak (delta Peak) is really just like sensitivity of the cut off charging point for the batteries. Think of it like a room temperature thermostat, the setting of the thermostat determines how long the heating is on before its switched off. In RC car circles, most racers advise for Nimh, you want a delta peak setting of around 20mv and about 5 mv for nicads. Im not certain what delta peak is best for Lipos. Timbo!? As regards discharging cells, most charger \ dischargers dont give a full discharg. To discharge nimh \ nicads, you're best investing in a discharger tray to get each cell equally to a cut off voltage of 1.1v. Bear in mind these trays generally only do 6 cell packs so if your flight pack has more than 6 cells, these wont be suitable.

Not a problem! Makes it worth waiting for. Only thought it would be 'next week' cos that's what it said at the end of the article.

Thanks very much for this article. Its just what the beginner needs. Can't wait for next week's article! Cheers.

If this is like Perkin's smaller cub, then its a great model!

I dont follow this. I have Futaba gear, low throttle is bottom stick ie stick towards the Tx holder, high throttle is top stick ie stick furthest away from Tx holder. If I 'reverse' the throttle channel, this makes high throttle at low stick and low throttle at high stick! Not recommended. Or am I missing something!?

I had an OS 40 (greate engine, btw) that had got gummed up and wouldnt turn over. So, I took the plug out and put a few drops of fuel in and left it for a couple of oil. Then I put some 3 in 1 in the plug hole and let it rest for another couple of hours. When I came back to it, it turned over a little so I put more 3 in 1 through the plug hole. I had to repeat this the next day when it started to free up. Once turning over freely, I put more oil in and turned it over some more until it was turning freely. Finally, I put it on the starter and promptly blew a load of oil out the plug hole but that seemed to be it!

Thanks David and Timbo for the comments. I understand the Futaba FF7 2.4Ghz has an extra feature that the 35Mhz FF7 doesnt 'ali-vator' not that I'd use it! I think its got a 10 model memory which is plenty for me (about 4 helis and the piper cub). Yep, I know most if not all the gear is compatible, thanks Timbo. But, I've been using Futaba for nigh on 20 years (used to be a Sanwa man before that!) so its a bit ingrained. Guess Im a bit of a stick in the mud!  

Has anyone bought one of the new Futaba FF7 2.4Ghz radios? All my gear is Futaba so their's is the only make I'll buy. Anyone got any reports on its functions and features? I know there have been a couple of hiccups with some 2.4Ghz but as with all things new, think its inevitable.

Cheers Timbo! They should pay you for all this advice!

OK, that does surprise me! What charging regime would you recommend for Lipos? I've seen in most of your posts you recommend charging at 1C of the pack's capacity but have I also seen somewhere you have recommended a charge rate at about three quarters of capacity (I might have dreamt that though!)? The charger I have seems to recommend plugging both the charge leads and balancer lead into the pack at the same time. Is this usual and would you say 'balancing' the pack was different to 'discharging' it? Could you enlighten me again here?

Cheers Timbo. Are lipos not like nicads \ Nimh packs in that they should be fully discharged before re charging, then?

Whoop-ee! New lipos and charger have now arrived (with other assorted goodies!). Im not yet ready to charge up the lipos as I've some building to do first. Question is though, what charge state can new lipos be left in and for how long? Should I charge them and just leave them, charge them and discharge them of charge them and partially discharge them? What voltages (its a 4s1p pack) should they be to leave them for a couple of months? How long can they be left between charges etc? Basically what charging regime should I follow?  TIA

What a great introduction to electric flying this Cessna would make! Almost ready to fly as well.  Count me in!

First ensure the soldering iron tip only has clean solder on it and is not contaminated with too much flux. Next 'tin' the wire to be soldered onto the plug. This is just making sure there's a nice even coating of solder on the wire. Position the wire close to the pin and re apply heat to the wire. When the solder melts, quickly position the wire and soldering iron tip to the plug. The solder should quickly flow onto the plug and form a good joint. The trick is not to use too heavy a soldering iron in delicate situations ie not 60watts! and dont leave the heat on the plug \ wire longer than necessary.

I was expecting sommat else!

Er, what does WOT stand for and what is it?

I only ever fly Futaba dual conversion FM TX and RX. I never mix other brands Rx's with the Tx. I intend to transfer to 2.4Ghz (who isnt?) when time allows and manufacturers can supply demand so have my eye on the Futaba 7ch set coming available now.

Timbo & Scott. Many thanks for your informative answers of the 27. That's precisely the info I was looking for regarding motors ie low kv. Totally agree about learning small bits of info, anything too large sends my brain into overload!

Just been reading the very unfortuante thread about the plane crash on its maiden flight. Very sad (but on a maiden flight I'd have thought the pilot would have done some gentle flying around rather than go into full aerobatic mode). Anyway, mention of 2.4Ghz and 35Mhz was made with the suggestion that 2.4Ghz with its superior interference rejection is ideally suited to leccie flying. Now I intend to convert to 2.4Ghz when any potential bugs have been ironed out and the sets are the basic bog standard 6 ch affair (yep I've seen Futaba have just brought out a 7 ch 2.4Ghz radio). After all anything that new has some issues with it initially. So, are there any problems using 35Mhz and leccie? Is there an ideal set up ie opto only esc etc? As always, advice, info (or insults) gratefully accepted  

Its for an approx 1\5th scale Piper Cub, weight about 5.5lbs. Obviously slow scale flying. But having said that, that was the point of my question. You've identified 3 different scenarios each with their own motor requirements. How is the newcomer to electric supposed to sort out what motor ratings are best for the type of plane you fly? With an ic plane, its fairly straightforward, a 40ic will produce almost the same power characteristics no matter what its application ie same fuel, same prop.

What's the best way to work out the 'required' brushless motor for your model? I've seen a couple of motors where the manufacturer has said the brushless motor is equivalent to, say, a 40 - 60 sized ic engine. However, the kv on one is 500kv and 900 watts while the other is just given as 600kv. Yet another as 900kv but being the equivalent of a 35 ic engine and suitable for the weight of model I have but the model manufacturer states a 40 to 46 ic engine is needed. How do you decide which is best suited for your needs? I know this forum is a great place for info but it would be good to work out whats required instead of having to ask all the time

Can someone tell me how lipo's should be stored when not in use!? Obviously unconnected but what's this storeage charge I've heard of a few times?