|Aug 06, 2012, 06:59 AM|
United States, FL, Hollywood
Joined Aug 2010
I have two Gens Ace 6S 5000mAh 60C to 120C batteries and they are only slightly warm after a 3.5 minute flight and I am doing flat spins, loops, inverted, etc. I am afraid to set the timer more than 3 minutes with my Zippy 4000mAh 40C battery since it is very hot after 3 minutes and is swelling.
My GForce 30C 6200mAh 6S has been thru a lot and is a bit swollen from my 90mm L-39 composite but it still works well with the SU-35 with the timer at 3 minutes. I would trust it for longer flight times if it was new.
Gens Ace 60C is the most worry free battery for me, used also with my L-39 90mm composite.
I use two 4S with my BAe Hawk 90mm
|Aug 06, 2012, 07:48 AM|
Nice flight V8, we use the same cam... Can you post a pic of how are you fixing the cam on the wing? Thanks!
Nice Videos Urrl too ^^
|Aug 06, 2012, 01:09 PM|
There is no short answer....
I don't debate that the GensAce or Genesis 5000, 5300, 5500 isn't a better battery to any zippy. I'd get the 5300 30C if they were around. They are light and IMO are at least good to 4000mAh use. But a few have burned up their 5300's in the 4 min region on this model so its not like they are bullet proof. Comparing a 4000 in this mix doesn't work because we all know if a 5000 can fly for 4 min with about 1500 mAh to recover with, you've killed a 4000 because it has nothing left. The paste can't be recovered. Which is why I always said Blue is fine as long as you don't push them too long or hard into the end capacity.
We end up abusing EDFs more by the nature of our flying.....Fast so we use up more sky, heavier so we have to be harder on the throttles to keep altitude, 3Ding a jet is just that much more, all hopefully for 4 min or more, with the lowest mAh because the battery is the heaviest thing in the model and batteries in this class can be as much as 125g+ difference. The 60C 5300 is about 810g. The hope is the 60C offers more some how. The 30C is already well above the amp demand so the hope is does the 60C deliver more watts or does it have less voltage sag and thus can use more of its 5300mAh and recover better.
C count and capacity mAh is the hope of X amps through out the specified capacity and with a higher C count the hope of a better compound. But not necessarily so. This says nothing of the energy density of the paste making up each cell or the physical state that its in once depleted. What voltage does it deliver under load? We no its not 6S because it sags into the 5S range. So are you spending an extra $60 dollars on something that you can't use, at a greater weight penalty to boot. That a question not a statement. Because so few give the specifics its hard to guess what the battery really is doing with just feelings conveyed. I posted the video to show that thus far all the batteries fly the puppy great. Just for a different window of time.
Anyways, with our EDF we near LVC usually much further out thus having to go deeper into the pack than we should trying to get back to the field because we estimated mAh in recharged but ESC cut out is based on a certain volts. Volt sag isn't linear to amp burn. Some sag right from the get go but if you are not drawing heavier amps you can stay above a voltage cutout while using up every last mAh that was in the compound. For this reason with Telemetry I keep asking for watts and mAh counter to be displayed to give a better sense of your battery being in distress.
Very few battery makers tell you the watts delivered at said amp rate. That would tell you the voltage sag and thus the energy density of the paste and if you can go closer to 1000 remaining mAh rather than not go much past 2000 remaining.
Having said all of this and why I said I'm still thinking.... all of them can do needed amps for a certain window. Some windows are longer than others. If my 4-5min window costs $160 and my 3-3.5 min window costs $80, as long as I don't push much past its limit I'm getting 6-7 minute to the cost of the 4-5 min battery. They weigh the same as the 30C5300 but lighter than the Genesis that cost even more. I just have to land more often. Which is why I got my 5800mAh battery for longer big sky cruising. Its 850g 100 g more so while I can get 1:1 I'm not going to use that battery for that kind of constant hard throttle setting. As long as I don't push the 5800 past 4500 demanding hard amps at that 4500 burn, the battery lasts.
But there are other flights where I want a hard burn for just a little longer the zippy is out, and without a huge weight penalty, which is where I'd take a 30C 5300 over a 60C if I get so little difference in return while paying the extra $60.
The Genesis 55C5500 vs the 5000 or 65C sees the same trade off at even more $$$.
So you see V8 doing the right thing.... fly hard on his cheapy for shorter window, land, swap, repeat. The only thing left is can the gear handle his... our extra landings going down this path.
Thus my first question whats the deal with the 5300s constantly being backorder.
Sorry for the long speech. But rather than having a continuing conversation may as well cover all the differing perspectives in one go.
|Aug 06, 2012, 09:17 PM|
Here are my measurements.
CG is 150 mm +- 2 mm
Stab neutral position is 17mm as shown in factory reference measurement. Started with factory then this is how it is trimmed after flight.
High rate up 43mm
Low rate up 30mm
High rate taken from outboard +10mm
Low rate +7mm
Flaps all rates outboard measurement Down -10mm
High rate Up position engaged +17mm
Low rate up +12mm
When disengaged for normal flight I have them set at plus 2 mm from zero zero using the hash marks cut in them from factory.
Weight ready for flight is 7Lbs 2.5 oz
Zippy 5000 40 C flight packs
Stock ESC with your cooling mod added
motors are stock gold 2300kv with stock fans statically then dynamically balanced. I also have FOD screens on all cheaters and factory intakes.
Flies super smooth and fully 3D capable with above settings. I did replace the main wheels with smaller 2" low bounce Dubros to change AOA for better takeoff .
I think that I covered everything. Flight is nice and level at all power range. Inverted flight requires some down fed in. 4 point rolls and regular aero stuff is clean and crisp. Normal flight tempreture is around 90 degrees ambient. Altitude is 4200 ft MSL. Full vertical to around 500 ft no problem. Most of the flight is 60% with aerobatic stuff to around 90%. Timer set to 4 mins with around 40% remaining after gear check pass and landing. So total time around 5 mins. Full powered flights at 4 mins have around 27% capacity remaining.
Please let me know if further info required.
|Aug 07, 2012, 07:41 AM|
Thank you so much ACE.
So just to make sure I'm understanding you and the one thing I was really looking for;
When your flaps are down 10mm, what position is the LE of the stab repositioned to from your 17mm neutral at CG150? Thanks.
Or what I'm looking for is max CL (coefficient lift), post stall + 10% velocity @
Takeoff: flaps to 15mm down, Pitch stabs to +Xmm from ref
Landing: flaps to 28mm down, Pitch stabs to +Xmm from ref
Since I have your CG and flap setting and can convert these to percentages, I can estimate, though its not linear, the % of stab input based on your numbers. This should provide a similar pre stall stability at a lower velocity.
Yes Jandro (in case you're thinking) the flight properties are not linear but I can at least ball park it. Other wise I'd have to calc the CL for each surface at each degree of deflection about neutral, along with the blended bodies CL at new approach AoA all of which we don't have.... So best guess.
|Aug 07, 2012, 08:42 AM|
Well, you can use XFLR5
Yesterday I measured my stabs in neutral and they where about 17mm too but it's not precise because they do not center at the same place each time and because of the wobble too...
I've noticed the plane has a little nose up tendency after some flights and I'm going to trim it down a bit.
I've finally installed the Ping Zheng LG and they work very smooth but needed to put the Gear Door on a spare channel because they don't like the servo reverser.
The Retracts turn mad if conected with a servo reverser, seems they do not know if they have to close or open, and start oscillating up and down.
Setting the reverser on the gear door is not possible because it alternates the time sequence so it wouldn't open the door before extending the legs.
So I'll have to buy the turnigy sequencer as you said but these reversers are from turnigy too. Has anyone tried the mentioned sequencer with Ping Zheng retracts?
Does it really works?
|Aug 07, 2012, 08:47 AM|
|Aug 07, 2012, 08:57 AM|
I edited my previous post with more info.
About XFLR5 you can make airfoil aerodynamic and stability analysis, also for complete wings.
In theory you can simulate classic bodies but they are a pain and it seems they only measure drag, so no deal for lifting bodies.
But you can take your time and draw a full body design from airfoils.
You are very likely to find trouble.
I understand it also crashes when trying to figure out the interaction with two closed coupled surfaces, so I would use it mainly for wing, foils and stabs analysis alone.
But it depends on your level of knowledge too!
If you have trouble getting it to work, ask me, I'm no expert but know a few tricks
PS: Ah yes, about foils, you can make them yourself, use NACA 4 and 5 digit standards or download special ones.
I think you can also add flaps but have never tried.
|Aug 07, 2012, 09:08 AM|
Not sure of your TX settings (mine are at 150%). The HK sequencer isn't turnigy. You can set direction, timing and the three controls, door, gear and door open then close back. Gives a few more options. I've worked it out on my F-35 with the PZs also. Just never tried it with the FW retracts and the PZs recently. I did when the FW retracts first came out but elected to go to 91s instead.
|Aug 07, 2012, 11:27 AM|
I've been using the reversers through the stock sequencer, maybe they don't work well toghether and cause problems to the retracts. I wasn't able to locate what was causing my issue but it stoped after removing the reversers.
|Aug 07, 2012, 12:30 PM|
Jando I used Velcro n tape to mount it. Pretty high tech! Nah im working on a removable clip with a swivle.
|Aug 07, 2012, 01:02 PM|
Here's another battery that im going to try, let you know how it is so you can add it to the list. Its 5000mah 40c @ 778g so it's lighter than the zippy 5000mah 40c. This is the one I just ordered.
They also have a cheaper 5000mah same brand.
|Aug 08, 2012, 08:56 AM|
The timing was either off or one wouldn't get triggered. If you pull the sequencer they'll likely work fine. In which case the HK sequencer will do the job.
|Aug 08, 2012, 12:02 PM|
Hi it seems the stock ESC's are still overheating and i'm thinking of changing them out. would the Hobbywing Pentium 80A esc be a good choice?
Also Max i have read some posts that talk about your esc cooling mod but i cant seem to find the post about the mod. is there some mod that will help the colling of the ESC? thanks for the help.
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