Freewing Su-35 (Vendor-independent; please read 1st post and stay on-topic) - Page 387 - RC Groups
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Jan 11, 2013, 09:11 AM
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Well, best is to work out what IS truly needed... get that , or better.....

Yes, the 43Amps Vampire, using a "60Amps capable" battery.... has leeway.
I have 10 of them and they run fine... fine enough. They do not like it if you WOT all flight.... but I don't anyway. So I am more likely using 35A area most of a flight.
Three of those batteries I had for a LONG time, and initially for use in a Dynam Meteor.. same CS10 2300kv combo, but freer flowing ducting means 50Amps area, or over a bit. Thus CLOSE to the batteries limits... no leeway.. they would get hot if I WOT overly much.. and I used to a lot! But in their early days they still coped fine with that. So those three batteries had a hard life!
And this burst one was one of those....

Those three tend to fly shorter flight time... instead of getting to the timer of 3min 45s they are weakening X amount sooner. So the plane slows.... I go "oh oh, better land NOW".... and they come down a bit puffed, a bit hot, but not too bad really. I do "know" if the power drops I have to get it down ASAP, so as not to overheat the battery. I am just pushing them out, in flights, to get my money's worth from them! LOL

Maybe not a good idea as it turns out NOW! hehe. But they have been like that for a long time ... so I have got tons more flights out of them. And the Vampire is not a fast plane, so lack lustre power is ok from those.

I would expect the 25C's used in some of the Su-35's would not be truly adequate long term. 5000 x 25 = 125A capable.... not a lot of leeway over typical Su power use. Even 30C still pushing things.... even by 40C only just beginning to be really adequate.
But like my Vampire, you can 'get away' with X amount if you keep it all under control and monitored. Well, unless you DO push it over the limit - again, like this Vampire case... doing the extra quick circle to check the landing gear was the fatal input! Adding maybe 20secs to an already critical situation.

My 5800mAH 30C for the Su-35 are not really up to it either. They are sort of like the Vampire battery situation (even the still good 20C ones), marginal, BUT, the Su-35 is not a low power aircraft like the Vampire is!! It is more in the category of the Meteor (which stressed those batteries!).
So those 30C are not likely to have their proper lifespan. All whilst not giving the 'proper' power levels the Su really 'needs' either. (esp my twin HETs in CS10's).
I have some 65C also though.

The stock Su-35 fan system could probably get away with X amount less.... maybe 40C area? (5000mAH). But it really has the ability to cane even a higher C! So in the Su-35 case I would recommend HIGH C.... and only lower C if you make sure you DO know how to keep things within limits. Adn even then, would lose some lifespan... offsetting your initial outlay cost saving.
In a high performance aircraft, you are more tied in to really need high eproformance battereis.
Last edited by PeterVRC; Jan 11, 2013 at 09:16 AM.
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Jan 11, 2013, 09:21 AM
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I am buying a Vampire myself for training purposes.I understand its a good model to learn the basics.
Jan 11, 2013, 09:34 AM
Should've, Would've, Could've
v8truckin's Avatar

Yes not worth the savings. Hence the reason we suggest using a higher C rating batter. So say he used a 3000mah 30c battery, well at 2000mah he will still be able to provide the 60a the motor is demanding from the battery. Where as the lesser 20c pack will only be able to deliver 40, but the motor is demanding 60a still. Its been discussed many times, so im trying to keep it to a min. If you want more info search it above
Last edited by v8truckin; Jan 11, 2013 at 09:44 AM.
Jan 11, 2013, 10:09 AM
ITTD you're Clear for Takeoff!
IntheTubeDeep's Avatar
Originally Posted by v8truckin
The quanum telemetry unit I use has alarms that let you can set thata way your not taking your eyes off the plane, unless an alarm goes off at the setpoint.
V8 how's that Quanum unit work? I've had it for a year and haven't hooked to a plane yet but will for my Su35 desert maiden
Jan 11, 2013, 10:16 AM
Should've, Would've, Could've
v8truckin's Avatar
Works great as long as it's a v2 but you do need to buy the amp/temp sensor seperatly from the unit. Haven't noticed any interference with my spektrum radio either.
Jan 11, 2013, 11:08 AM
You are a "go" for reentry
Maxthrottle's Avatar
Its Friday! How did I lose a day in there?
Thanks for the answer Pete. I assume the redundancy is driven by the spit in RX control between the two RXs. I was wondering if Natalia was going to have two small RX batts for each BEC.

Joining in the pages conversation; Redundancy I tend to fly a separate small LiPo or LiFe battery because of the nature of the two most common failures to an electric; a bad cell or blown FET. Either can induce a failure in the other and they tend to short the entire system. I haven't found a way around that so I wondered if you came up with another level that I hadn't heard/thought of.

If you have a questionable cell, pushing it over a long circuit length works the FETs harder and the ESC can fail in a short making what ever number of BECs you have, internal external useless. Externals at least have a better chance.
If a single cell, though balanced at charge is under performing in use well you see the same conclusion. Watching the batt as a pack masks what may be happening on a cell that's about to toast.

As for telemetry, having to drop LOS is risky. Thus some of the Telem systems have programmable audible read out. And they don't have to have constant number read out of an entire list, they can be set to only alarm any out of parameter conditions. Jeti is demonstrating a great thought out setup in this regard with even tilting the DS-16 to activate what ever desired read out. Thats not to promote Jeti, just the logic in the setup. Others could do the same they just haven't fully yet. I also like ear buds to receive that readout rather than creating more noise for other at the field and distinguishing mine from others.
If they gave a out of parameter on individual cells, you could declare emergency and get down while you still have control before you cook something.

mAh capacity issue, battery fuel gauge, Volts vs Amps ... some what solved in the fuel gauges of modern electric cars. Estimated range isn't reliable but a gauge that considers the capacity at charge, the max amps the batt is able to hold regardless of life cycle then has a accurate capacity state to relate both why you may be low volting and how much amps you still have in the tank. The RC world just hasn't embraced that yet. I imagine you'd need a small charge recorder to go on the end of the balance wires that stays with the battery and hooks up to the Telem fuel gauge. Still in concept.

C rating; it depends on how you intend to fly the model. If you plan on flying 0.65:1 TWR or less, a lower C rated battery with higher capacity will do. How EDFs differ from their prop cousins I find is, we didn't usually hover our props with an over sized prop, on a heavy plane repeatedly through out the flight. EDFs require more power in to achieve velocity with a slower acceleration, doing so at higher loading. Our short bursts to see the kind of response needed is like trying one more hover on a prop even after you near LVC. So the battery has to be up to that abuse if the flying style isn't conserving momentum and energy state (hard tight turns, 3D, Hard fly bys, extra go arounds). For the average flying I think we said 40-45C is more respectable for the life cycle of the battery. Below this if pushed hard, you induce a shorter battery life cycle. So for you new to EDF, your 25C may look to perform, but this will likely be short term.
Jan 11, 2013, 11:20 AM
You are a "go" for reentry
Maxthrottle's Avatar
Actually Pete, what's the range on the blue tooth. Is it a proximity readout or does it do so at range. Cause if it does blue tooth is supposed to remain a low watt out system.

While I like an alternate telem read out to a mobile device for a co pilot, I'd still want the device to have audible readout in my ear if I was to use it. The key to any telem IMO is alerting only out of parameter conditions. Otherwise I'd never look at it. I guess to with a selected button, speed and altitude for landings.

Or are you guys thinking using the look thru camera app on many mobiles now, to view the sky while having the telemetry readout overlay on screen? with the phone hanging off the rim of a hat
Hmmmm that could be useful and still wouldn't breach flight association rules as being a FPV type setup if one eye remains unaided
Jan 11, 2013, 01:21 PM
ITTD you're Clear for Takeoff!
IntheTubeDeep's Avatar
Originally Posted by PeterVRC
Bloody control arm problems.....
I don't quite have useful bits to implement the control arm I need/want on the airbrake pivot shaft. It all moves as planned, but needs a very low/short control arm on that pivot - to stay clear of the battery.
Optimal would have been if I could braze something onto it (metal to metal), to be small and solid. More thinking/planning needed on this part....

I also made the airbrake assembly removable. The airbrake pivot is clamped by a... umm... "clamping pivot bush unit"... so you can unbolt that and release the airbrake assembly from the hatch.
I forget exactly why I planned for that.... it seemed a useful idea...

And I got all my "Su-35 paints" (Acrylics) matched up, so I have the set for repairing/painting the plane now.
When I saw the cool pics of your AirBrake I was thinking you might have a few issues on the pivot point since you have the hinge below the surface (compared to the hollow tubes I cut into the top of the brake and panel) , thought you might have some binding issues and difficulty with the control arm/connecting rod. My issues was I only had that 90 degree ELE servo available, if you have a landing gear servo or 120 degree it would have made the mechanism easier and allow a much longer control rod and higher location on the airbrake itself for the control horn thus more strength in the entire lifting mechanism. I was experimenting with the screw drive retract mechanism from my MiG29-- still tinkering! Hope you get some more pics up soon!
Jan 11, 2013, 01:53 PM
Flying Hazard
SU-4ever's Avatar
Hey, my new Sukhoi has arrived at last!

Oh wait, that's not a Su-35...
Jan 11, 2013, 02:29 PM
Suspended Account
Seems like the mail has been good to many folks today! I just got 3 boxes from Hobby King myself today. I never realised these 6 cell batteries were so MASSAVE in size before!. These batteries are so big I bet they would even start my car up. Preliminary cell check shows all 6 cells in 1 battery at 8.7 and on the second one they are all above 8.something except 1 cell that reads 3.77. 22.8 together in all 6 cells I hope they balance out ok after a few charges!. I wonder how these batteries will work with my SU35?
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Last edited by goldsworthy; Jan 11, 2013 at 02:35 PM.
Jan 11, 2013, 02:37 PM
Should've, Would've, Could've
v8truckin's Avatar
Do a few cycle charges and they should be fine.
Jan 11, 2013, 02:45 PM
Suspended Account
Originally Posted by v8truckin
Do a few cycle charges and they should be fine.
I hope you are right! these 2 batteries were not cheap in price. I hope buying one with this C rating will work good on my SU35 and last awhile. I really want to just leave these batteries alone and not charge them the first time until I am ready to use the 35. Should I wait or just charge them now?. I think it would take MANY hours to storage charge them again after charge.
Jan 11, 2013, 02:50 PM
You are a "go" for reentry
Maxthrottle's Avatar
The hinge he fabricated is a 90* hinge just the same; not offset. If you made that arm an L he could have used that to pivot the air brake but that would take a strong servo to actuate with a short horn to clear the battery.

You could use a piston travel type actuation or an equidistant trifecta actuation around the hinge point.
I sketch some of this out when I dreamt of making a 27 year back. Oh I should add the piston method can be done in either direction aft as in the pictures or fore ahead of the hinge line.
Last edited by Maxthrottle; Jan 11, 2013 at 03:03 PM.
Jan 11, 2013, 03:00 PM
You are a "go" for reentry
Maxthrottle's Avatar
Originally Posted by goldsworthy
I hope you are right! these 2 batteries were not cheap in price. I hope buying one with this C rating will work good on my SU35 and last awhile. I really want to just leave these batteries alone and not charge them the first time until I am ready to use the 35. Should I wait or just charge them now?. I think it would take MANY hours to storage charge them again after charge.
Cycle them anytime before you fly but return them to a standby state for any time between when you've cycled them and intend to fly.
There are no guarantees with Lipos against cell in-balances and C rating. C rating only means they perform with higher amp deliverable with available capacity.
And individual cell fails happen on the most expensive to the cheap. ISome manufacturers test and match cells together. Cheaps... doesn't seem to much and I think only Maxamp guarantees against it replacing the battery if it does. They are so expensive you are practically buying two batteries for the price of one.
Jan 11, 2013, 04:46 PM
Registered User
Also.... see if you have a way to check/calibrate that Lipo "tester" you used.
I have four different ones like that and they are all flakey in their accuracy. Use all four and you have four different sets of numbers!!
The FRsky FLVS-01 is very accurate - at least mine seems to be. So the other four are half useless rubbish really! (all those look similar design to your pic)
So I only use those as a very quick rough check to see if a battery is used/charged or not. Ignoring the exact cell voltage reported.

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