Any news on the Trex 500?

[skeppley]

I'm not really familiar with the A123's, but I dont think a 6S A123 puts out the same voltage as a 6S lipo when loaded. You would probably need a 8 cell A123 or so.

[Jason Chow]

okay, something tells me to go to the distrution center b/c its in the US and in socal, woohoo :)

[Razor_Racer]

7s A123 is the same nominal voltage as a 6s lipo. Although the extra weight might make it feel heavy.

[Finless]

I may have a suprise tomorrow as I am stopping by somewhere local to get some video :)
Hint Hint.....

Bob

[LITHIUMSTATIC]

Spill the beans Bob....:)

[kgfly]

I am hoping that A123 packs will fit and balance but if you are after wild 3D then lipo is still your best choice. For learning, sport flying and mild 3D 4s-6s A123 will do with the bonuses of no fire risk and 4C charging.

Consider these representative configurations:

Comparison of LiPo and A123 packs for a 500-class eHeli
================================================== =====
Assumes:
a) Top quality lipo holds 3.5V/cell under load

b) A123 holds 2.8V/cell under load

c) Runtime is related to available energy: Wh = no_cells x V_per_cell x mAh_capacity/1000 x usable %
LiPo = no_cells x 3.5 x capacity/1000 x 0.80 = 0.00280 x no_cells x mAh
A123 = no_cells x 2.8 x capacity/1000 x 0.90 = 0.00252 x no_cells x mAh

d) For maximum lifetime in excess of 100 cycles for lipos usable power is about 75% of nominal for high quality packs.
For A123 FMADirect measurements showed that 16c/33c were good operating points for 500+ cycles.
The estimates below take these guidelines into account and the real maximum power that can be delivered is
considerably higher for both technologies.

---- ----- -------- ------ ------ ------- ------------ -----
Pack Cells Capacity Weight Energy Rating Power Price
(mAh) (g) (Wh) (W) USD
---- ----- -------- ------ ------ ------- ------------ -----
Lipo 4s 3700 380 41 20c/30c 800 - 1200 ~220
Lipo 5s 3300 420 46 20c/30c 900 - 1300 ~220
Lipo 6s 2170 350 37 25c/50c 900 - 1700 ~180
Lipo 6s 2500 350 42 18c/27c 700 - 1100 ~180
---- ----- -------- ------ ------ ------- ------------ -----
A123 4s 2300 300 23 16c/33c 400 - 850 ~50
A123 5s 2300 375 29 16c/33c 500 - 1100 ~60
A123 6s 2300 450 35 16c/33c 600 - 1300 ~70
A123 7s 2300 525 41 16c/33c 700 - 1500 ~80
---- ----- -------- ------ ------ ------- ------------ -----


IMO it is very unlikely that a 7s pack will fit and/or balance, even 6s might be a challenge. As you can see, the peak power and flight durations will generally be lower than for lipo. 4s will be fine for learners and basic FF. 5s-6s will be needed for more vigorous flying.

[Ginvent]

just get creative with cell placemnet who says they have to be in one confined "Pack"

[Big Fil]

I may have a suprise tomorrow as I am stopping by somewhere local to get some video :)
Hint Hint.....

Bob


Cool, so you'll have full build videos by tommorrow night then:lol:

[rcasey212]

I may have a suprise tomorrow as I am stopping by somewhere local to get some video :)
Hint Hint.....

Yes yes YES! This is going to help me decide between T500 and T600! Bring it!

[kgfly]

just get creative with cell placemnet who says they have to be in one confined "Pack"

Sure, but most people won't go beyond splitting the pack into two parts that can be easily mounted without affecting the aesthetics of the heli. For example mounting one below the baseplate under the main shaft is not something most will consider. Some of us of course will try all kinds of weird stuff just for fun :thumbup:

[OICU812]

Personal thoughts are this would be a very boring heli on a heavy battery setup, Put out some bucks and get a good lipo and be done with it imho. :wink:

[Jason Chow]

bob, where is the video?

[brovic777]

bob, where is the video?

Yea, where's the video of Jason Chow test flying the Trex 500 at the AlignRC shop in the OC??????

[kgfly]

Personal thoughts are this would be a very boring heli on a heavy battery setup, Put out some bucks and get a good lipo and be done with it imho. :wink:

I agree, for you Shawn that would be so, you are an expert pilot used to flying very high power setups. I suggest that there are many more of us beginner/intermediate/sport flyers with bent thumbs, poor perception, lousy coordination or just less experience for whom the many benefits of an A123 solution far outweigh (pun intended) the affect of a few extra grams on a heli this size. Besides, you can choose between weight and flight time by choosing how many cells to run.

As you can see from the figures above, one could have three 6s A123 2300 packs giving comparable performance to a single 5s 3300 or three 5s A123 2300 packs for comparable performance to 3 6s 2500 lipos. Flight times would be about 1/3rd less but you still come out ahead in terms of flights/hour (3 packs each of which can be charged in under 20 minutes compared to 1 pack that at best charges in 40 minutes). Add in no fires, 10A charging and 500+ cycles and that's pretty compelling for some of us, but it certainly is not for everyone.

I agree that for anyone wanting maximum performance LiPo is still the best option.

[heliboy88]

I really wanna know if 4s, say 3300-3700mah pack will be enough for mild 3D, will the power be inadequate? How about the approx. flight times? And also if using 2x 2100mah 3S packs in series, will the flight times be very short?

[Laddy]

http://www.thetrexforums.com/?topic=2287.msg26792#msg26792
500L brushless motor with different test configurations:

4S 3200mAh battery:
Violent 3D - flying time of about 5.5 minutes
General 3D/F3C - flying time of about 8 minutes

5S 3200mAh battery:
Violent 3D - flying time of about 5.5 - 6 minutes
General 3D/F3C - flying time of about 9 minutes

6S 2100-2200mAh battery:
Violent 3D - flying time of about 4.5 minutes
General 3D/F3C - flying time of about 8 minutes

6S 2500mAh battery:
Violent 3-D - flying time of about 5 minutes
General 3D/F3C - flying time of about 8.5 - 9 minutes

[heliboy88]

Thanks a lot Laddy, i've seen that table too. But is the power really adequate with 4s? I've seen one of the vids claiming that 4s is being used, but due to the music you couldn't really hear anything about the motor bogging, etc. Just by looking at the 3D moves, they all seemed to have the same performances comparing to other 6s vids, but i think it's the pilot(pros) that's compensating the lack of power with the sticks. Any idea?
I ask cus i really want one, but if i have to go 5s or 6s1p for this heli i'll have to think about it really hard(you know the costs of those packs). But if 4s is really powerful enough for this bird that'll be a great news, at least for me.

[Laddy]

You should wait till people are flying it and see what they say. However some will say it is great and some will say it a dog. You know how it works:)
I will be going with the 6s 2200 at first to see how it is.

[kgfly]

The other helis in the 500-class fly well on 4s 3300-3700 so I see no reason this one won't. Those that want wild power will go with 5s or 6s.

[heliboy88]

Thanks a lot Laddy and kgfly, i think you guys are right. But hay, check out the sticky vid of finless' interview of the T500. The guy(Andy Yu) said he's doing 3D with 2 x 3s trex450 packs for 7 mins. That's really cool, and if that really workout well, i don't have the power problem anymore:lol:. And the T500 looks just great.:thumbup:

[OICU812]

I agree, for you Shawn that would be so, you are an expert pilot used to flying very high power setups. I suggest that there are many more of us beginner/intermediate/sport flyers with bent thumbs, poor perception, lousy coordination or just less experience for whom the many benefits of an A123 solution far outweigh (pun intended) the affect of a few extra grams on a heli this size. Besides, you can choose between weight and flight time by choosing how many cells to run.

As you can see from the figures above, one could have three 6s A123 2300 packs giving comparable performance to a single 5s 3300 or three 5s A123 2300 packs for comparable performance to 3 6s 2500 lipos. Flight times would be about 1/3rd less but you still come out ahead in terms of flights/hour (3 packs each of which can be charged in under 20 minutes compared to 1 pack that at best charges in 40 minutes). Add in no fires, 10A charging and 500+ cycles and that's pretty compelling for some of us, but it certainly is not for everyone.

I agree that for anyone wanting maximum performance LiPo is still the best option.

Ok well I do see your point and you are correct. My apoligies, I guess I am one tracked minded towards ballz out power and performance. Honestly as well I can admidt I have not ever ran or tried a A123 setup, I am just going by the weight is all. Be well. By the way I certainly do not consider myself an expert by any means, lol. :wink:

[rcboosted]

Actually, I don't think the weigh would be that bad. The 6S 2500 set up will weigh about 425g on EVO25.
My old 4S A123 pack weighs 330g. At 6S A123, it will be 495g. 70g difference on a 1800g heli is about 4%. I don't think you'll even notice that it's there. To match voltage for voltage, 7S might be needed. That will give it a 577g, that's around 150g more. 8% difference in weight.

[Finless]

I video'd Andy flying it today!!! Will have the vid up tomorrow AM

Bob

[Nyther]

Thanks Bob for keeping us updated:).

Ken

[RH>]

hello, do you guys think it´s gonna come in 4 or 6 cells ?? or both??
i hope i 4 cells.. beacuse if i doesen´t, i have to buy new charger and balancer. :thinking

but what do you think??