Dean Pappas

Hello All,
I have noticed that my Pattern testbed is consuming about 60% of the radio battery capacity, as compared to a similar setup wet-powered. My last few wet Pattern setups all consumed about 145 mAH per FAI practice flight. I am now seeing something more like 80 to 85 mAH. Dave Lockhart's first flights on his Pletty powered Abbra are following suit.

What are you all seeing for radio power consumption?
Dean

can773

My Feedback: (1)

Hey Dean,

I am seeing about half that for 10 minute flights, around 40-50 mA, or about 1/3 of my glow setup.

Servos are Futaba, x2 9154's, x2 9650's, x1 9351....5.6V reg.

Adamg-RCU

50mAh for an 11minute (P05+a few try-agains) flight. Mantis, 9411's in ailerons, 8611 on rudder, two 3421's in stab, 6.0v regulator, 2s lipo pack, Plettenberg Xtra 25-13, APC 19x12WE.

EHFAI

Amazing what a little vibration can do. I observed a significant reduction in power consumption with glo when I switched to a Hyde mount (Myrle has quantified this and includes it in his claims). Somewhere I've DSA (dynamic signal analyzer) data from mini accelerometers mounted to aileron servos - kinda scary. My original observations were with analog servos - even a bigger deal with digitals (in terms of power consumption).

My findings with E are similar to the other posts, around 50 mah for a P-07.

ExFokkerFlyer

My Feedback: (4)

About 40 mah per 8-9 minute Masters practice flight. Fut. 9550 on rudder and elevator, 9650 on aileron with a 6V regulator. My other airplane, an Impact, with two 9650 for elevators, Hitec 5945 on rudder, and two other karbonite Hitec digitals on aileron was at about 65 mah per 9 minute practice flight.

Dean Pappas

Hi Gang,
Thanks for the replies. So the current reduction is as dramatic as I had thought!

Of course, there is a limit as to how small we can make our flight packs: both for cell resistance /regulator dropout reasons, and because one binding servo will still pull the same high current. We probably need enough to withstand a full flight with a near stalled servo. Provided you do a voltage check after each flight, that should prevent an unnecessary disaster.

later,
Dean

can773

My Feedback: (1)

Correction....my regulator I found out last night was 6.5V output lol.

Will have to check them more carefully in the future!

Jeff-RCU

My Feedback: (4)

Dean,
I'm coming into Electrics from a different direction of Electric Ducted Fans. In these, most people seem to be not using seperate reciever battery packs, but using a UBEC to step down the voltage from the Li-poly to power the receiver. Any reason you guys are not doing this in pattern.

Jeff

can773

My Feedback: (1)

I think that the addition of 1-2 oz of weight to a 10.5 lb model for the security of an independant airborne power setup is good cause for most to run separate Rx packs.

I have heard of a number of UBEC and other BEC failures when ran with high input voltages like we have (42V).

Beyond that, there are very few BEC's (that I have seen anyways!) that have high current ratings....with 5-6 digital servos on board the BEC needs to be able to supply 5A+ on occasion...many are only rated to 1.5-3A.

OhD

Hi Dean,

In my DA100 powered Extra, I put a 6 volt, 1.5 amp regulator at each servo and ran the 8.4 volts all over the plane, so I wouldn't need to worry about voltage drop in the long cables. An added benefit is that a shorted/stalled servo causes the respective regulator to shut down and draw very little current. The remaining servos don't see any degradation even with a dead short. Also each servo is isolated from the 8.4 volt bus so no voltage ripple is seen when the other servos are drawing current.

This is probably overkill for a pattern plane but I believe something everyone should consider in IMAC type planes.

Jim O

Dean Pappas

Hi Jim,
That makes all the sense in the world.
It's got to be overkill, even though we are looking at a high crest-to-average current consumption ratio, now that the servos not fighting vibration.

I also need to collect some prop RPM versus output power figures for a handful of props I have data on.
That's on another thread, though.
Thanks and later,
Dean

Jeff-RCU

My Feedback: (4)

Just curious. Seems like sometimes we kill for an ounce! THe UBEC i'm using is good for 47 volts input, 3amps continuous output, spikes to 5 amps. Of course on an EDF not only is weight a constraint, but space also. I'm currently pulling 45 amps out of a 4S with this set up.

Adamg-RCU

Jeff, a standalone BEC is a very good option. I would probably go with it if I had to pay for my 2s RX lipo packs.