View Full Version : 4 horsepower Pantera

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11-12-2009, 10:33 PM
We flew the P50E-r1 today making 2860 watts, or just about 4 horsepower (746w/hp). 5 minute flight on a pair of 3700mAh Evo25 cells used abvout 80% of them (10S=38 volts). Lots of fun seeing 98A on full blast collective climb outs, which were simply wicked. The packs are old and thus we didn't see the max power we could have with 30C or 35C packs. Imagine how this puppy would respond on fresh batteries because during hard climb-outs thesepacks were dropping to 28.5V.

Meanwhile, we've sussed out the r2 for the electric conversion, which is more simple and is what we'll offer. But testing is still going apace for now using the r1 because there's n performance difference and this is just a prototype. By the way, we also flew with a pair of 4S 5000mAh packs (8S since they're in series) and we're seeing 80A, at 1750 RPM and 8 minutes easy (and thinking we can get 10 minutes). This was a really nice and mellow sport set up perfect for learning (both examples using a common 630kV motor). On 8S, or about 30 volts nominal. The same motor on 10S was governed to 2000 RPM (due to more voltage), and tomorrow we're shooting for more because the governor should have some headroom left. Meanwhile, the gears showed no distress and next we're going to 12S. We should change to a 500 kV motor because now we'll be at about 45 volts, give or take, nominal (if we stuck with the 630kV motor this would see the head at 2500RPM and with the small head we're not going to take a chance . . . probably). This really calls for the XL head, which is the real purpose of this testing. As it turns out, we've been having so much fun things are delayed a little bit. Nevertheless, this should be a yee haw experience!

More as it develops, but if you're interested, this is some of what's going on at the swamp this week.

11-12-2009, 10:42 PM
Very Nice! I have your model on my radar. I'd like to get the BOGO and throw an OS-70 in one and Novarossi 91 or YS-91 in the other.:thumbup:

Ray K.
11-12-2009, 11:45 PM
4 whole horsepower!?!?!?!

Wow. that's at least 20% better than a typical .90. That thing will be a weapon on 12S!


11-12-2009, 11:50 PM
I would be very interested in this as I work from the house a lot, and I can throw up an electric easily, but I cant' really do that too much with a nitro right now.

It would get me into a bigger bird, instead of the 4-5 packs a day of my 450.

11-13-2009, 12:08 AM
No Ray, you misunderstand, that's 4 horsepower on 10S. The only reason we didn't see the full 3000W out of the motor is the internal resistance of the old packs is too high (they're 25C packs). Nowadays it's common as dirt to find 35C and 40C and greater if you're willing to pony up for them. me? I'll be perfectly happy on 30 or 35C packs, heck I'm happy with the 25C packs, which are dirt cheap by comparison.nowadays. Anyway, on 12S we're going north of 4 horsepower, e.g. 5+ (maybe 5.3 hp). Best of all, the 6S packs we've got 30C packs, which are newer to boot so if we see 100A on 40V we have 4000 watts, which divided by 746 watts/horsepower = 5.3 wild ass mustangs!

Anyway, with respect to big electrics, e.g. bigger than a 450, it's only money. Real world, figure one $280 charger per set of packs (at present, a Hyperion with balancer built in). You'll want 3 or 4 pack sets (e.g. two 6S in series to make the 12S pack), and of course, some way of powering the chargers. I'm using an 80A power supply at 13.6 volts, or close to 1100 watts and since it's 75 to 80% efficient, multiply by 1.25 equals 1360 watts going into the supply. At the field, you'll need a 1000W Honda generator because in practice you're not charging a butt load of totally discharged batteries at the same time (or keep your car idling).

Ray K.
11-13-2009, 12:22 AM
That sounds like a lot of work... the amount of gear and investment required sounds kind of like flying a turbine!

I have known since I started flying my 450 that electric is the way to go, but it can be prohibitively expensive for normal guys like me to campaign a 600-size or larger electric. I think I remember doing the math at one point and determining that I was going to spend the same amount of money on a complete nitro 50 setup as I would on batteries and chargers alone for a similarly-sized electric model. It's too bad, because I feel that electric is the way to go. It's got better power, better power management, the heli doesn't change weight throughout the flight, and they sure seem to vibrate a whole lot less. And they're clean.

Anyway, thanks for the clarification, John, and I'm looking forward to hearing more!


11-13-2009, 12:26 AM
Ho Ho Ho... I know that fun!

I have a 600 electric with a 980KV motor and a 100amp ESC.
With 6S 5000Mh pack (30C) when you do the math, you get about 3HP.

I know that feeling when you bang on the throttle :YeaBaby:

A Pantera with 4HP electric must be a lot of fun!

Can you post some pics/video, please?

11-13-2009, 01:28 AM
Pics? Sorry, not right now . . . too busy having fun. Look folks, it's about 1:30 1 AM and we're only now about to shut down for the day! Anyway, tomorrow (today, Friday), e.g. later today is the big day. Why? Because we flight test the XL conversion for the first time. Think 8 lb 14 oz Pantera, with a 91, and 710 mm blades.

Or opt for 12S, and she's still dirt cheap, tank tough, and you can grow in whatever direction strikes your fancy, e.g. a cheap 50-class beater for 200 bucks, which is pretty darn capable right out of the box. Or stuff a 91 in her and have fun racing bottle rockets (and your pals paying out the nose for the newest Hyper).

Or maybe extend the head/tail boom, or convert it to electric, whatever and best of all, you don't break the bank when (not if) you smack terra firma because it's still just a Pantera to repair. What's not to like?

Anyway, during difficult economic times, it's time to fly smarter, e.g. not waste money As for us, we'll fly and have fun and not worry overly much because we're getting everything dialed in, sales are picking up steam as the word spreads, and this is a good sign for those Audacious enough to make their own way, e.g. not always follow the crowd.

11-13-2009, 11:12 AM

Still running the HV85? I hit over 100A several times on the initial testing last year, it always held up well and stayed cool. The HV110 might be a nice combo when you finish the package, but the price is a big jump up. If you only see a few spikes over the 80, I'd say the HV85 would be plenty.

fyi, I posted my eagle tree logs on wattflyer at the time if anyone wants to search

11-13-2009, 11:40 AM
We believe the 85HV would handle the 8S configuration as we were flying it yesterday. The reson we're using a 110A unit is connector compatibility (with the motors we're testing_. Now on 10S we're not so sanguine of the 85HV and on 12S we're just running scared, which is why since it was more convenient to just change from the get go, we're already to proceed with testing without having to swap out speed controls. E.g. nothing wrong with what the R0 version had (yours) just more conveninet for testing.

We're performing limits testing today using 12A. The 8S 5000mAh is a nice pack for sport flying with a motor selection optimized for 38 volts, e.g. buy a 630kV, which is perfect for the voltage we're running and the gear ratio available. Moreover, duration is nice and everything is cool on landing. No question there are many ways to skin an electric cat, but we feel higher than the 630kV motor is not best in this application.

For 12S, we're changing motors to 500kV (45 volts remeber, so multiply kv by volts and divide by gear ratio to solve for main rotor rpm).

11-13-2009, 12:43 PM
PM sent

11-13-2009, 07:32 PM
OK If I get my Ducted Fan working right, I will need to come up with some mods. to get the power up some more. I WANT TO BE TOP DOG. :P

What size blades and how much pitch ya pullin?

11-14-2009, 10:43 AM
To everybody asking when and how much . . .

I'm sorry but it's too soon to tell. Frankly, we're engaged in product testing. For example, today we're engaged in additional limit testing, e.g. does it blow up? We've successfuly performed limit testing with 8S and 10S packs. Yoday, we're using a 12S pack with the same 630kV motor today, e.g. 630kV x 45.6V = a big number.

This is multiplied by some percentage for efficiency, then divided by the gear ratio and the result is another big number, which we suspect 'might' explode the Pantera. This is why it's called limit testing!

Anyway, when we know you'll know, which I recognize is unsatisfying but we're in untrodden territory and nobody knows the answer yet. It's why I haven't said too too much publicly. More as it develops, I promise.

Ray K.
11-14-2009, 11:09 AM
John, you have the coolest job in the world!

I my line of work, I "scientifically" destroy car parts, and I get a grin out of it every day. It also satisfies the engineer in me to test things and try new designs out. To be able to combine that with model helicopters must be a blast! I know from experience that limit / ultimate performance testing can be dangerous and exciting all at the same time, and I wish I could see what you guys are up to!

This is the type of testing that reveals new limits and fosters innovation. The fact that you're so vocal about what you're doing is one of the things that makes me so excited to fly an Audacity model! Keep it up!

"I have not failed 1000 times.... I have simply found 1000 ways that don't work."
-Thomas Edison


11-14-2009, 01:22 PM
Update . . . 2760 RPM without finding the limit, e.g. destruction. We saw a little over 3500 watts, maybe 4.7 horsepower, which exceeds the capability of the motor (for long term use, e.g. flying around). Moreover, we saw 77A, no strange results, e.g. gears survived (as expected), the blade bolts did not bend, there are no obvious signs of deformation. What this means to some of you (Mr. HillBilly, and his OS 91 ducted fan engine comes to mind), is have fun!

Meanwhile, to those who have asked how fast can they run their Pantera head, I'm sorry but we've once again exceeded the capability of being able to measure it to destruction. Simply put, while we've previously seen 2500 RPM with the YS91SR (accidentally), the only thing we learned then was where it didn't fail. Frankly, this isn't very satisfying. Worse, today (using our usual 139 g blades), we still don't know (we know what it is in a load cell but this is real world, e.g. blades turning). Hence, we have negative results again, i.e. the limit test failed again. Why? Simply because we can't put enough horsepower into the Pantera head to break it with what we have on hand.

In other words, any kind of 50-class engine on the planet, 50SX Hyper, the 55 Hyper, the various odd engines like Novarossi .57 and KNE .60 are quite likely safe simply because they're port limited, e.g. won't run past perhaps 20,000 RPM, which divided by the gear ratio of 8.7:1 works out to about 2300 RPM. Of course, OS Max only claims 2.1 horsepower from their new .55 Hyper, and under max pitch so it's impossible to get this this kind of RPM, so with any pitch on the blades to speak of a real world 50 probably won't break a bone stock Pantera 50 head.

Is this our blessing to go try? No, absolutely not! Nothing has changed and we still do not reliably know where this bone stock Pantera 50 head fails. Moreover, we do not desire to extrapolate to every one of them that exist, and consequently, we continue to maintain the "never exceed" speed rating of a Pantera 50 head is 1850 RPM, which means if you exceed this it's on you instead of us.

11-14-2009, 01:32 PM
2750 two words for you JB. OH BABY Dude you are nuts I love it.

DId yours get a whistle when it hit 2500 or better? I lost a mag. and I am guessing my DF was at about 2500 or better and it had a whistle sound to it.

we continue to maintain the "never exceed" speed rating of a Pantera 50 head at 1850 RPM, which means exceeding this is on you, not us.

That is the best way to put it right there, if it blows up in your face it is your own problem.

11-14-2009, 02:48 PM
Pantera 2 is going to be a nitro 55, Pantera 2 could still become an electric.

11-14-2009, 10:52 PM
And you're worried about spinning 710's on the stock heads??!! I haven't done the math but I'm thinkin that the loading on the blade grips (and bolts) at that speed would have to be pretty close to the same as spinning 710's in the 1900 to 1950 range. I think this means that your stock setup is a lot more solid than you give credit to, John.


11-14-2009, 11:40 PM
Looks like JB is coming over to the wild side with us Tom. :thumbup:

2700+ on a Pantera, that has got to sound MEAN in a hover.

11-15-2009, 08:11 AM
Im mounting 810mm blades RIGHT NOW!!.... 3D baby!

1850 on a stock head..PSSTTTppp!..... 810mm at 2500 rpm is more like it!!

11-15-2009, 01:25 PM
Good morning everybody! Steve, Perry, and Max have departed after a productive week with some of the Crew. Meanwhile, Lynn's off grocery shopping and thus, I have the Alabama vs. Mississippi State replay going on ESPN 360 (via Lynn's laptop to the living room TV), and I can take a few minutes to bring you guys up to date using my laptop.

Anyway, with the 630kV motor on 8S, 10S, and 12S, using 139 g, 600mm blades, stock tail blades, and with as many as 5 ponies pounding through the system, which complete maxxed out at 2760 RPM, nothing broke. Tentative conclusion #1 is the 630kV motor is really nice on 8S for 8-10 minute relaxed flights, or learning to hover. On 10S, the Pantera equipped this way is quite exciting, e.g. 5 minute flights without stressing the packs and waaaaay more power than a 91. On 12S, the motor is at risk, and it really makes no sense. This is a 10S setup for performance use, or 8S for sport use. Also, FWIW, these results are using 4S-5000 mAh, 5S-3700 mAh and 6S-5000 mAh packs. The latter are really massive and the machine is just too heavy for 600 mm blades. This brings up an interesting point.

The purpose of this week wasn't to test any of this. The purpose of this week was to test the XL conversion option. Cutting to the chase, the XL conversion is a larger head assembly so I could offer the long tail boom/belt that permits 710 mm blades. In short, want a 91? Combine BBC and XL conversions and presto, go have fun at 9 lbs. I mean go have fun!

A secondary purpose was the electric stuff, which is interesting but basically I am a nitro guy. I love the sound and the fury, the smell, etc. Moreover, I confirmed what I knew all along, doing electric is expensive. In short, you really need a $300 charger/balancer for each set of packs for practical flight, or about $500 per set and you need a minimum of 3 sets, or $1500 worth of fuel, which you buy all up front and God help you if you crash your case of fuel and set fire to your model. or otherwise destroy one pack, because in effect you really wipe out two packs because they like to be balanced to each other. Is this a hard and fast 'rule'? No, but for practical matters it is for most of us who don't make a hobby out of our batteries as well.

That said, I also learned I am an electric guy as well as a nitro guy because there is a very, very nice place for electric in my view, which is in a scale fuselage. More about this in the future.

Switching to a 500kV motor and 6S packs (12S is 45V) makes for a really exciting combo with the XL package because 710 mm main rotor blades can make for a complete personality change from a Pantera with 600 mm blades because the disk loading drops through the floor. This is an 11 pound machine with 5000mAh cells. We didn't have 6S-4000mAh packs to try, but I suspect tis would be delightful because we're back into the 9-ish pound range with 4500W, wchich is astonishing!

By the way, at this point (710mm main rotor blades) the stock tail blades aren't up to the task (if pushed), and switching to 105 mm long tail rotor blades delivers better results. Moreover, the tail rotor grips are well up to the task as well, in my view. Interestingly, this combo on 8S is an armchair heli, or really perfect for learning because we set ID1 for 1300 RPM, 1500 RPM on ID2, can easily loop and roll. She then hovers like a dream but still sport flys for quite a while - 8 minutes easy. Swap to 10S and she becomes an, "Oh my God, this is fun!" experience.

Frankly, I'd have to fly back to back (I'll just have to find time to built up another model so I can do this easily) to determine if I prefer 10S with an XL conversion or 10S with 600 mm blades. Either way, I believe for 'me' 10S is the way to go.

Why? well, frankly, it's too soon to say but I suspect the real answer is, "it depends". Of course, I won't know for sure until I build time and develop more experience. One factor is it's easier to chareg a pair of 10S packs than 12S lipo packs. My Thunder Power charger simply won't do 12S, so this neccessates a Hyperion charger, which is another 300 bucks, give or take by the time it's here. Of course, 6S packs cost a bit more than 5S packs as well. Moreover, quite frankly, I don't know that I want to mess around with this as a daily model because it's a bit of a handul. So were back to 10S, which stuffed into a fuselage would be a delight but for all around flying, I love nitro.

Anyway, we'll work to finish developing the electric conversions and offer them, perhaps by Christmas, but no promises because tempus fugit like crazy at this time of year as family obligations are especially important. E.g. Niki's husband has been assiged duty in north Florida and they'll be moving here and while he's at a school for two months, she's going to be living with us. Of course, there's the prospects of seeing my mother, etc.

Alabama is ahead and I am stoked (though mostly because Lynn just walked in the door which means breakfast in a little while - my fat ass is hungry since dinner was a long time ago), so back to my day off from work . . . you're up to date.

11-19-2009, 07:36 PM
So how much of my kit can I assemble with out the parts for the electric and xl conversions? It will look good assembled on my coffee table waiting on the other parts, plus it will give me something to do infront of the TV watching Airwolf or Star Trek re-runs :YeaBaby:

Also how is the Scorpion 4025-630kv at risk in a 12s configuration?

Checking further it seems many are running the Scorpion 630kv 12s in their Trex 600ESP without issues.

The Pantera is built tougher IMHO, as I have both the Pantera and the 600ESP, the third bearing block being already installed is a huge plus for me, as its an upgrade, and a pain to purchase the old 600e shaft, and install the third bearing (different bearing than the first 2 also) in the 600esp kit.

I can't wait for the E conversion to come out, it's perfect for me!

11-20-2009, 07:00 AM

Yes, the motor is at RISK with 12S. We did it simply because we thought it would live for a short run whilest the 800kV motor likely wouldn't and the 500kV wouldn't give us what we needed in the way of RPM for a limit test.

However, do you want to know what's really a hoot? A 500kV motor on 8S 5000mAh, with 690/95mm blades in the evenings at 1350 RPMs swatting mosquitoes for 10 minutes . . . and only putting 3000mAh back into the battery!

Talk about no stress fun - wow!

12-20-2009, 12:13 AM
Bumpster !

12-20-2009, 01:28 AM
So how much of my kit can I assemble with out the parts for the electric and xl conversions? It will look good assembled on my coffee table waiting on the other parts, plus it will give me something to do infront of the TV watching Airwolf or Star Trek re-runs :YeaBaby:

Also how is the Scorpion 4025-630kv at risk in a 12s configuration?

Checking further it seems many are running the Scorpion 630kv 12s in their Trex 600ESP without issues.

The Pantera is built tougher IMHO, as I have both the Pantera and the 600ESP, the third bearing block being already installed is a huge plus for me, as its an upgrade, and a pain to purchase the old 600e shaft, and install the third bearing (different bearing than the first 2 also) in the 600esp kit.

I can't wait for the E conversion to come out, it's perfect for me!

The 4025-630 is not "at risk" on 12S. The only thing that would be at risk would be the rotor system from over speeding do to improper pinion selection. From his posts it appearers john is new to HV setups and doesn't quite understand the relationship between volts - amps - and watts.

The 4025-630 is rated at 2700 watts which on paper equals 3.62076 HP. In the real world you have to take into account things like bearing friction side load forces from driving the main gear and electronic inefficiencies in the speed controller itself which all add up to an operating efficiency percentage. which is usually for helis figured at 85% to 90% max.

So the best case scenario is about 3.25 HP. Thats one HP more than a Hyper 50!!

One other thing to note: no mater how many volts you throw at a motor it will only produce it's rated HP. You don't get more HP on 12S than on 8S. It's still a 2700 watt motor. A spike on a data logger is NOT HP. It's just a peak in the amp draw. If you hold full pitch for 30 seconds you'll see the spike drop back to around the motors rated wattage.

In my 600E I run 20C Zippys (as in $33,00 for 2650mah & $38.00 for 3000mah) and can sport fly for 12min.
and only put back 65%. No need for high C packs with 12S unless your doing extreme 3D and need every last speck of power you can get your hands on.

Hope this helps clears things up,