woodie

The efficiency increases as the daimeter increases. That is why we can get away with slower turning props. However, having said that, at some point the pitch speed (rpm x pitch) will come into play. If you want to turn glow props, you just about have to turn them roughly the same speed as the glow motor will which usually means you need a higher kv motor (or more volts) to get to that rpm.

A lot of us have gone to 13, 14 and 15" pitch electric props to have the speed available when we need it. Given the wind demands, some change props (pitch) depending on the wind, others may run the higher pitched props all the time and just throttle up when they need the speed. With our computer radios, it is easy to have various 'settings' whether they be conditions or dual rates to control how high the motor will turn.

I have been running a 20x13 APCe on my Dualsky 6360 and have flown in winds in the 25mph range with no performance problems. Yes, I was pulling slightly more from my packs but still no capacity problem. Have tried the 20x15 which some have good success with and the plane will definitely 'move out'. Throttle response is different, I think you have to fly the 20x15 more like a 2 cycle motor to get consistent speeds, others may have better ideas how to use it.

Recently, I have tried a 20.5x14 APCe (not a wide blade) and it looks like it may be a good combination for controllable speed and thrust. Only have a few flights on it but it 'feels good', just faster than my 20x13.

Steve has described his efforts to reduce weight and maintain performance and I think it is great we are pushing the envelope to find out what the limits are for batteries, motors, weight, etc. And I would add, if you haven't flown an electric plane back to back flights with the first at 8+ oz heavier then drop the weight, it is VERY noticable. Uplines are much easier to maintain a constant speed, downlines are noticeably slower.

A few of us here in NorCal have been experimenting with mid range settings and have been able to reduce the overall mah usage per flight a considerable amount without sacrificing any vertical performance. Flights are in my 10.75lb Genesis. This is a combination of lowering the midrange cruise speed and increasing the prop pitch. I can now fly a full P07 flight with med to large maneuvers at what I consider a nice speed (not slow) and still handle the wind and use under 3000mah from a TP5300 10S pack. This has been proven in competition in the last 2 contests around here with both in pretty substantial wind. We have done this with both outrunner and inrunner type motors. I have not tried lighter batteries in my Genesis , but could comfortably drop to 3700s with capacity to spare at this point and it would drop the weight about 6 oz further dropping the mah required.

The trick is to not force the plane to accelerate quickly just to get to cruise speed. Any throttle setting higher than what you need is just burning amps in acceleration just to get to the cruise speed. This has made a surprising difference in the total mah used.

Don

Scott Smith

My Feedback: (4)

Hi Chuck,

I've got about 40 flights on my ePatriot so far. Running a 17x10 eAPC on the A60-20S. It will turn 8000 rpm at 70A and has a lot more apparent power then a 140RX.

I have about 5 flights now with fixed end points on the ESC and 85% high end (~60A at full throttle)…still plenty of power and consuming about 2500 ma for the Master’s sequence (and there was a pretty good breeze this morning.)

RC_Pattern_Flyer

My Feedback: (1)

Well, i got a nifty little package containing a 19X12 prop.
so.. grab the batts, bolt on the prop, grab the transmitter, head outside, ARM.. CONTACT.. fire it up, whatever it takes.
So, throttle up, max amps around 57 at full throttle and pulls like a freight train.
Again, the motor jumps timing only near 95% throttle but not every time, only if i go full quickly. Would this be less likely in the air?
So, i will probably use steves throttle curve mix to limit the motor to 55amps full throttle and...........i should be able to easily fly as the plane wanted to JUMP into the air.
I did some checking of amps and i believe at a steady cruise the plane will be pulling around 18 amp or less. kinda surprised me here. I am very anxious and so far pleased with the setup and all of the Dualsky equipment. The quality is excellent and everything has worked fine, just me learning the setup.

I hope to maiden on monday if the weather holds nicely.
The 18X12 and 19X10 wil probably arrive wednesday.

Cant wait to here more from you each of you on setups and reactions to trying new things.

Chuck Hochhalter

xalm04

Hi Don, could you explain more on this? I have been flying my e-plane for about 9 months so far, and never had less consumption that 2900 mAh for a full P07. I'm beginning to try several throttle curves, and put my ESC curve on exponential shape, however this caused to use more mAh instead of less. My plane weights a little over 10.75 lb, with a Hacker C50 14XL, 21x13W APC propeller and TP 4200 mAH batteries, and I may add that I fly at 9000 feet of altitude, however energy for a complete pattern flight is the same no matter where you are, right? so variations can exist due to less air to pull in the prop but also there is less air to produce drag on the plane.

Any explanation on how to pull less mAh is very welcome. Thanks.

patternrules

My Feedback: (6)

A little update I've got 72 flights on the 3300's and they seem to be doing ok. I have 3 or 4 flights where the ending no load voltage where it was between 34.5 and 35.5 right after flight NO setting time, which is running the pack really to low, it always happened when I would get to far out which make manuvuers bigger, if I stay at 150 It comes in at 36.5 or higher which I feel is safe. Yesterday I had it down to 34.5 and one cell was off by .127 volts which is to far out of balance, but I done a couple of short cycles on it and it's back to normal. Hopefully tomorrow I will post the a graph of 75 flights. At this point in time I feel if your very careful you can get by wiith the 3300's but the safer bet is the 3700- 3850.
Steve Maxwell

RC_Pattern_Flyer

My Feedback: (1)

I will begin posting data as soon and i get my bugs out of the new plane and trimmed in so i can give real flight numbers through the squence. Boy, wish i could fly PO7 haha, but i fear the plane wouldnt make it through the sequence.... hahahaha.

Anyhow, thanks Steve for your input and ideas, sometimes we need to explore things fo a different avenue and you sir are doign that.

Chuck

woodie

I have my Jeti set on Linear. I use an outrunner, but the approach has yielded similar results with a Hacker inrunner. In the Hacker test, he uses even more pitch than I do.

Basically, there are 2 things to experiment with to lower the mah.

First, you need to lower the mid range or cruise settings of your throttle curve. I found I was basically forcing the plane to accelerate to my cruising speed by throttling up instead of using a 'cruise' throttle position and leaving it alone and let the plane reach 'speed' more gradually. This sounds obvious, but next time you fly be very aware of how you throttle the plane and when. If you are pushing over the top of a maneuver and leaving the throttle up to get to cruising speed, try reducing the throttle position to cruise as soon as you have established a stable speed, then let the plane accelerate more slowly. (Sounds like 2-cycle glo flying doesn't it). See my throttle curve picture below. It used to be higher in the middle section before. You will need to shape your own curve to feel good to you, but the most important item here is get the middle part lower. Most planes have a comfortable horizontal cruising/maneuvering speed. Chances are it actually lower in the throttle curve than you currently are flying.

Second, try going up a little in pitch and maybe down in diameter. Since you are are 9000 feet, this may not work for you. I fly mostly at sea level or near it so my findings are based on having lots of 'air'. I went from a 21x12W to a 20x13 and didn't give up any vertical speed. I do use a little more throttle in the uplines than I did before due to the loss of diameter but my speed is about the same. I do have to slow down a little sooner for downlines than with the 21x13W but it is pretty minor.

When you couple the addln pitch with the reduced mid range in throttle curve which is where you spend the majority of your horizontal time, the net result has been a pretty dramatic reduction in overall usage. As I mentioned above, one other person in this area has done similar tests with a Hacker inrunner with similar results but he is using a 14" prop.

I use TP5300 and FP5350s so I have plenty of capacity to fly P07 using larger props but I haven't noticed any drop off in scores or flight performance using the technique above. Not a scientific study but it works for me. I was typically using around 35-3700 mah with the larger props, now I consistently use about 2700....

Sorry for the delayed response, I missed your question in this thread and just noticed it today.

Woodie

shannah

My Feedback: (5)

[/quote]

See my throttle curve picture below. It used to be higher in the middle section before. You will need to shape your own curve to feel good to you, but the most important item here is get the middle part lower. Most planes have a comfortable horizontal cruising/maneuvering speed. Chances are it actually lower in the throttle curve than you currently are flying.


[/quote]

Hi,
I'd like to see the throttle curve when you have a chance to post it.

Thanks

woodie

sorry bout that........ I added the throttle curve pix to my post

Woodie

shannah

My Feedback: (5)

Thanks!!!

patternrules

My Feedback: (6)

As promised here are a couple of graphs one of the 3300's with 77 flights, one of the 3850 with 29 flights. I think all in all the 3700-3850 are the best bet as it's way to easy to over fly the 3300's and any needs the proper setup to work well. So like it says before DON'T TRY UNLESS YOUR VERY CAREFUL!!!! You can clearly see that I have overrun the volts on the 3300's flying to far out and that really hurts the battery but the 3850 seem to be doing better. Ending voltage tells the whole story.
Steve Maxwell

pmr

Patternrules,

What schedule do you fly with your figures? Thanks

patternrules

My Feedback: (6)

I fly masters, the last few years I have flown FAI P patterns with similar numbers, but haven't tried the P-07 as of yet with this setup. I'm going to change props to get a little better pull which will use more amps.
I'm sure and the 3300's are marginal at best, which the charts about clearly shows the 3300's ending voltage is to low at below 36 volts but with the 3850's the ending voltage is 36.75 which fine.
Everyone please note this was an experiment to see how far I could push the limits of batteries, not by any means to be a standard, the 3300's are starting to show signs of big inbalance at the end of flights which I feel is directly related to the over discharge because of flying to far out. The other part of this experiment is the motors windings right? Is there a right motor that is smaller that will give the performance we need? Are the props right for motor windings? More to be tested as new motors with different winding and props of different pitch and diameter become available.
Radio setup is very important as others have stated, I'm flying with a DX7 which doesn't give me as many options as the higher end radios so I beleive that I could make this work even better when the 9 channel is released.
This has been fun and educational experiment, I'm not a rich guy and it hasn't broke me so all is good, I do feel if I had some more money to test some different things it could even get better.

patternrules

My Feedback: (6)

Well I have desided to try a set of the TP 4200 prolites as they are lighter than the 3850 and still has more than enough power for my application. Wish they made a 14 pitch prop for this motor, I've been told I need more speed.
I'm abanding the 3300's as a little short on power but can work if you keep manuvers small and and at 150 meters or closer, I have 90 flights on them now and there still doing fine, it's been a fun and an inexpensive experiment.
Good luck to all of the testers we have in this great game.
Steve Maxwell

patternrules

My Feedback: (6)

Forgot to add I went back to the 19X12 E prop and have played with a 17X13 glow prop 19x12 e has more thrust but the 17X13 has more speed may use it on really windy days if needed.
Steve Maxwell

patternrules

My Feedback: (6)

Like I said earlier if it wasn't for Tom Messerand I for got to add Al Messer, I would have never tried any of this.
Thanks to both of you and I hope Tom comes back to his sences and pattern soon LOL.
Steve Maxwell

Derek.Koopowitz

Yeah we miss Tom as well over here in California - but he's got a new job flying for Virgin America and he's spent a ton of time in training and getting his teeth whitened!

patternrules

My Feedback: (6)

A little update I slightly puffed a pack of 3850's today, 2 things may have contributed to this, first flights went fine but on the second flight my packs came off the charger at 114 degrees not sure why I checked them but I did and glad I did, and wind was to my back at 10-15 MPH which as usual moved me out, next to last manuvuer in masters is a immelman and I noticed it wasn't climbing like it generally does, like it done at the shootout with the 3300's but this time I finished the sequence,got down and the batteries had a slight puff to them, temp was 165 degrees which has always been below 145 and generally 130-135 at hottest point at 90 degrees outside air temps. I have always had plenty with the 3850's no matter what so the only thing as of now was the starting heat of the packs didn't get a chance to check motor amps which i beleive is fine but will check tomorrow. So tonight I'm making a battery cooler like RM shows in this thread. http://www.rcuniverse.com/forum/m_5908765/tm.htm.
Might also add that I cooled the other 3850 down to 75 degrees before my final flight of the day and it was fine so I'm sure the problem was the starting heat of the pack.
Steve Maxwell

patternrules

My Feedback: (6)

Ok today I check amps and they was fine same as normal, so it had to be the heat of the batteries going into the plane. As you might expect the puffed pack has issues now below is a graph of the normal flight and one of the puffed pack the difference is huge anyone can see if watching that the puffed pack doesn't have as much power by a big margin. As of now I'm thinking of going back to 5300's for the spare MAH they have and the throttle responce I feel is best for pattern as I feel that the Extreme packs dump power to easy which means 2 things #1 they can run out of power faster than the prolites but prolites will heat up more because of the resistence that keeps the C rating lower, #2 throttle responce with the prolites have a much more linear feeling than the Exteme pack, and this comes from not just me but other pilots as well.
For me I can't make the 3300's or 3850's work for how I like to fly, only if you can fly smaller and closer will this system work well for you over time, the smaller motor might still be enough but will have to see back to back with 3850's and 5300's. I know the 5300 prolites are the most expensive packs to fly but I feel that they are still the best for 2 meter pattern, it still take care to make any electric setup to work, what I have tried to do is give an honest report at my own expense as to what is possible, pushing the limits as far as I can funny that the 3300's had still been doing ok and still could be but under the summer heat they would have had problem I believe also.
In conclusion is it possible to make a truely lighter setup for 2 meter pattern YES, can anyone do it NO, I have enjoyed doing these test and would like to continue with otther batteries like the prolite 4200's but funds are running low, the good thing is it didn't break the bank to do this, I haven't lost a plane because of it, no fires just one pack with a lose of power.
I leave you with one thought be very careful of testing and don't over look anything as I did. Be aware of longevity of packs $ per flight.

Steve Maxwell
PS the first graph is of the puffed pack and short flight, the second is of the same pack with 29 flights on it. the 3850 that puffed had 64 flights when I puffed it. Please note min. volts.

shannah

My Feedback: (5)

I thought that if a pack was "puffed" you shouldn't charge it and that you should dispose of it.

ExFokkerFlyer

My Feedback: (4)

Well I'm not sure about the teeth whitening comment, but the rest is true enough. Derek, was that some sort of hint there buddy? LOL I miss the gang too, but I'm not totally out of pattern yet. I may show up when you least expect it, and I am planning on running the Gardnerville contest in August if all goes according to plan.

Steve has taken the smaller powerplant to the next level in testing, not sure how much if any I or my father had to do with it though. We simply tried some things that others hadn't, that used to be what this hobby was all about. I for one never thought a 3300 would be enough, and maybe it's not, but Steve got further than i though he would for sure, good job. I do think that with the right airframe we could reduce the size of the motors and batteries significantly, and that's what this thread has definitely shown is 'possible'.

Thanks for the kind words guys,

Tom M.

patternrules

My Feedback: (6)

Shannah: On another forum they talk about charging at a very low rate .30 amps and in a safe place with a good charger and balancer, now with that said there seems to be levels of "pufffed" just from what I have seen mine was only slightly puffed and I set them aside for a long time to see if they got worse, they didn't, it was barely noticable, I seen others that was so bad that the cells got to twice the size which wasn't my case. The other thing is I don't think the power will ever be back to normal if puffed, or at least mine didn't and they was the lowest puff I had ever seen.

Tom: good to see you still hanging around. Yes the 3300's surprised me too 90 good flights and still going, but I feel that during the summer heat they would have been toast if I kept using them. From what I can see now is ambient temp compared to battery temp is on a very expotentional curve at below 70 degrees the packs done fine, at 80 was getting close to maxed out, at 90 it showed up in the next to last manuvuer, maybe just maybe if I had the foresight to kool them to 70 degrees before I flew I might even be able to make them work on 90 day, but it would really be pushing them. One the things that may hurt was they was a 10's instead of 2-5's packs which may have a better cooling if setup right. This was proven when the 3850's puffed after doing so well, I'd still like to try the 4200 prolites and see how they do, I know of at least one flyer that used them because of a weight problem last year, and from what I heard he could tell the difference in performance because of the weight loose, and that was on a Hacker setup. Now would they last and get the cost down like I was searching for I don't know haven't actually talked to the person myself, and I will at the Nats, as I have known him from the 80's.

Steve Maxwell

Derek.Koopowitz

Err... just a comment about all the smiling you'll be doing when the passengers offboard - got to show those pearly whites! [8D]

Hopefully we'll get to see you next weekend at your home field.

ExFokkerFlyer

My Feedback: (4)

As far as puffed batts go, they all are likely to 'puff' at some point or another. If you look at a fresh battery, specifically the Enerland cells (Flight Power/TP Extreme), the sides are flat and the actual cell shape is rectangluar, square corners and slab sided, more than it's not. Under normal use and lets say 20-30 cycles you may see a certain 'rounding' to the cells. I have heard this described as 'puffing' before, in fact when I first started with electrics thats what I thought 'puffing' was... that is until I REALLY puffed one! This isn't puffing, just the effects of normal use. The batts are still firm to the touch, nothing soft, and the general shape is similar to the original. Looking at the end view of the pack, the cells look more like a rectangle than an oval, though the sides may be SLIGHTLY curved. This is still okay.

I have had new packs that have puffed due to a deep discharge a few times. I set them aside for a bit and watched them. If they were able to take a charge (all but one did) then I used them again. I still have most of them. I did have one though that was defective, though I didn't know it at first, that puffed and I was able to use it again for a few cycles. I didn't fly the batteries for about two weeks once, and when I went to charge them up before a session I noticed a pack was puffed up again. Now, this time I was able to see that one of the cells was leaking, a definite 'no-go'.

My advice is if you have a cell that is just rounded and firm to the touch, it's likely fine. If you have one that puffs, set it aside and monitor it, and like with an ankle sprain, the 'swelling' will go down and you can charge it up and use it again. Though it should be said that after the first charge after the 'puffer' flight, you should fly with caution, say five minutes instead of 10 just to be safe. If you still have issues, take it up with your manufacturer or where you got the batt, it could be defective.

Tom M.

RC_Pattern_Flyer

My Feedback: (1)

Just wanted to update everyone.. i flew the 6350 Dualsky Motor with an 18X12E prop this weekend through the advanced schedule.
Flight 1- 2000 mah
Flight 2- 2400 mah
Flight 3- 2200 mah

I had more than enough power and had the motor detuned to only pull 60 amps max and never got to full throttle in the uplines anyways.

I will get a datalogger and post more info later as I play with it some more. Might try the Masters pattern for fun.. just try not to CRASH!! hahaha

Chuck Hochhalter