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Old Oct 27, 2010, 11:07 PM
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Boise, ID
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Hyperion ZS4020-12 and Revolver .46-.70 EP

Need some advice about power for a plane. I think I'm beginning to understand some of this amp/volt/watt/thrust/weight relationship, but not sure.

Just completed the build of a Great Planes Revolver .46-.70 EP. This is a 7 - 8 lb plane, a sport plane that I want to fly smooth, fast, with moderate aerobatics. (See picture) I haven't weighed it, but my guess is it will be between seven and eight pounds.

The motor GP recommends is a RimFire 42-60-800, which is 800 rpm/v. GP recommends an APC 11x5.5 Electric Prop. Recommends two 3S batts, in series, and that's what I have, and also a Hyperion 6S 5000 mAh batt. So, voltage is about 24.

I like Hyperion motors. I could have bought the Hyperion ZS4020-8 (777 rpm/v) but the 4020-12 was recommended for this plane, so that's what I bought, and that's 543 rpm/v.

I have the APC 11x5.5E prop on it.

OK, so here's my question: Knowing that an aerobatic plane should be pulling about 100+ watts per pound, this one bench tests at 634 watts, with my Eflite watt meter, which may be only approximately acccurate, so shouldn't I have a motor/prop combination that pulls 800-1000 watts?

634 watts is about 79 - 90 watts per pound. So, if I have the 543 rpm/v motor, should I prop up to where it pulls about 1000 watts? Maybe a 11 x 10E, or 13x8E?

Hyperion shows the following watts for these props:

11x10E 906W
12x8E 857W
13x8E 1028

If I should prop up to one of these, how will the performance change, with each prop?

If I fly with the 11x5.5E, will it fly OK?
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Old Oct 28, 2010, 02:42 AM
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Bruce Abbott's Avatar
Hastings, New Zealand
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90W/lb would be 'OK' except that it will run out of pitch speed at about 45mph, so in-flight performance will be very poor (this model likes to do at least 60mph).

Quote:
Hyperion shows the following watts for these props:

11x10E 906W
12x8E 857W
13x8E 1028
Those wattages are for 5S Lipo, not 6S. On 6S the 11x10 would draw about 1400W, the 12x8 about 1300W, and the 13x8 about 1600W. The 11x10 should give the best speed, but the 12x8 and 13x8 would give better climb (should go straight up on the 13x8).
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Old Oct 28, 2010, 10:55 AM
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Boise, ID
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Bruce, Thanks for the info.

Couple questions: Do you have this plane? If so, do you know its approx stall speed, that is, the speed when it will tip stall and spiral into the ground? (I'm kind of new at RC still, and if you have any tips about flying it, I'm all ears.)

Second, you're right about the 5S numbers. Where did you get those watt numbers for the props?

I'm inclined to try all those props. The motor and ESC are good to 90 amps, about 75 amps extended, which would be about 16oo watts. There is clearance for a 13" prop. Will probably try the 12x8 first, as that should give me max flying time plus good climb.

Tom
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Old Oct 28, 2010, 02:32 PM
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Bruce Abbott's Avatar
Hastings, New Zealand
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I don't have a revolver, but the stall speed can be calculated from its wing area and AUW. At 563sq.in and 8lb this works out to ~29mph.

I got the Watt numbers for 6S using Motocalc. I started by using Hyperion's 5S figures to get the motor constants, then simply upped the cell count to 6S. This program also works out the model's flight characterstics (stall speed, climb rate etc.).
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Old Oct 31, 2010, 04:36 PM
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Boise, ID
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Thanks Bruce! My wattmeter shows only about 900+ watts at WOT, from a 6S batt and an APC 12x8E prop. This is bench test, of course. Compared to 1300 watts expected, could it be that the Hyperion Zs motor is just super efficient?

Also, I finally weighed it. With two TP 3S 4350 mAh batts, it weighs 7 lbs, 2 oz. A little lighter than I thought. I think that 12x8 prop will be fine, but bought the others and will try them out. At first, I'll be interested in easy flying and long flight times). (Only my third plane, and biggest by far, so far. Taxi-tested yesterday out at my club field, but chickened out from doing a maiden flight.)
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Old Oct 31, 2010, 05:10 PM
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Fourdan's Avatar
Antony (France)
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Quote:
Originally Posted by tlr-boise View Post
Thanks Bruce! My wattmeter shows only about 900+ watts at WOT, from a 6S batt and an APC 12x8E prop. This is bench test, of course. Compared to 1300 watts expected, could it be that the Hyperion Zs motor is just super efficient?

Also, I finally weighed it. With two TP 3S 4350 mAh batts, it weighs 7 lbs, 2 oz. A little lighter than I thought. I think that 12x8 prop will be fine, but bought the others and will try them out. At first, I'll be interested in easy flying and long flight times). (Only my third plane, and biggest by far, so far. Taxi-tested yesterday out at my club field, but chickened out from doing a maiden flight.)
Hi Boise
Just for an order of magnitude and for your info
If you run Scorpion Calc (free)
here http://www.rcgroups.com/forums/showthread.php?t=736782
6S LiPo
Scorpion S 4020-12 Kv 540 rpm/V (close to ZS4020-12)
APC 12x8E
You find around 1000W 22.15V 45.7A 10710 rpm thrust 6.6 kgf
Regards
Louis
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Old Oct 31, 2010, 10:36 PM
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Boise,

I'm flying the Great Planes Reactor using the Scorpion 4020-12 (Which appears to be very similiar to the Hyperion motor you discussed) with a flight weight of 6lbs 8oz. When I use my Turnigy 6s, 4000 mah batteries, I get performance numbers very similiar to what was presented in the previous post (as measured by the Castle ICE data logging esc). Since your Revolver is of similiar weight and wing loading, I think you will be very happy with the setup. I have settled on a Xoar 13x8 prop and consitently get flight times of 10+ minutes using < 75 % of the battery capacity doing moderate aerobatics. If you are constantly at full throttle, flight times will decrease substantially.

Bob
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Old Nov 01, 2010, 04:17 AM
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Bruce Abbott's Avatar
Hastings, New Zealand
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Quote:
Originally Posted by tlr-boise View Post
My wattmeter shows only about 900+ watts at WOT, from a 6S batt and an APC 12x8E prop. This is bench test, of course. Compared to 1300 watts expected, could it be that the Hyperion Zs motor is just super efficient?
1300 Watts is expected if your battery puts out the same voltage per cell as in Hyperion's 5S test (3.89V/cell). If your battery was putting out a lower voltage then power would also be down, eg. 3.5V/cell (21V total) would reduce power to 1050W.

Of course, all these calculations presume that Hyperion's figures are accurate!

ETA Boise, ID is at an elevation of 2800ft. Reduced air pressure at that altitude knocks another 63W off my last figure, making it 987W. Still plenty
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Old Nov 02, 2010, 03:55 PM
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Boise, ID
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Thanks Louis, Bob, and Bruce!

I feel much better about the power setup now. Scorpions and Hyperions are identical, more or less. One of those companies bought the other, or they joined in some manner, and I think both are top of the line, as far as good magnets, advanced design, etc. are concerned.

Bruce, I'm going to check that battery. It's a batt with one cell slightly crunched and has higerh IR that the others, and I don't fly with it much any more, as it takes forever to charge it. Just use it for quick bench tests, but I'll check to see if the voltage is where it should be. Thanks for the tips!

Now if I can just get up the nerve to actually fly it!
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Old Nov 02, 2010, 07:22 PM
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hillsboro Oregon
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Good luck with this plane, i recently just ordered the 70" version. I will be running the Rimfire 1.20 50-65-450kv. i am going to try the 6s power setup first
with a 16x10 or a 17x8, either one is going to produce around 1400 watts. Word of warning to you, practice your approaches before you set it down and make sure you have pletty of runway, this thing likes to glide
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Old Nov 02, 2010, 09:33 PM
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Mikeochs, Thanks. Have you flown this one? I ask because that's exactly the advice I got from a guy here who has both the small and large Revolvers. He said it lands real hot, essentially, and glides forever. My maiden flight, I expect, will be a short, easy flight with a lot of touch and go's, and then I'll being it in and take a breath. My club has a nice long blacktop runway. It's 700' x 48'. I'll probably use all of it.
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Old Nov 02, 2010, 11:09 PM
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hillsboro Oregon
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nope, but a guy at are club has one and it is a real chore for someone that does not have alot of stick time on that type of plane, very streamline and cut throught the air nice so there aint much room for error. Keep your low rates down until you get comfortable. I have a edge 540t of that same size with a 75ax and it is a real bear to land unless i got about 3-5 mph head wind witch makes it nice.
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Old Nov 21, 2010, 04:43 PM
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Mike and everybody,

Thanks for all your help with my questions.

Update: Maidened the Revolver Friday afternoon, finally. Flew it up, out and around and practiced landings. That thing does lands hot. Made four flights and four landings, and three of them were bouncy. Scraped each wingtip, a little.

Flew with an APC 12x8 prop. Whether it’s the Hyperion motor, or my conservative flying style (about 60-70% throttle), I flew it about 15 min and used up 70% of a 6S 5000mAh Hyperion battery. I was surprised. With two of those Thunder Power 3S 4350 mAh batts, again flew almost 15 min and used about 80%. Flying time was much more than I expected.

With this 543 Kv Hyperion motor, I'm going to experiment with 13" props, and maybe even larger. The plane seems to fly around slowly. Maybe it just seems that way, since it's a larger plane than I've flown before, but about 80 mph is supposedly good, and there was no way that the WOT runs down the runway were 80 mph.

An unexpected treat: Four A-10’s flew overhead very low, from south to north, after bombing the desert area south. They flew under low clouds, and disappeared into the haze north of the freeway. Have to just stop and watch those things; pretty cool.
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Old Nov 23, 2010, 03:21 PM
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Canada, ON, Owen Sound
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Use an APC 12/12 E prop!! You won't think it slow then. I run a Kelly with the Scorpion 4020-12 (same,same) with this prop, it goes 124.6 mph on gps!! I will climb straight up at over 100 mph. Plane weighs 6lb,4ozs RTF. 6S/5000 Rhinos
I find it hard to believe yours is over 7 lbs! Doug Bartley
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