Does this sound right?

[wilinfla]

I am finishing up a conversion of my Sig Astro Hog Bipe to electric power. I have the following system in it. E-Flte 90 motor, Castle Ice HV120 ESC, Thunder Power 6S,3850mah, 45C battery. I have a 17/8 APC prop on it. When I ran a check with my wattmeter it shows 33 amps at 750 watts. Does that seem low? The plane will be 7.5 pounds so this gives me 100 watts per pound, I just thought I would see more power from this combo.

Will

[flydiver]

Would appear so.
http://www.e-fliterc.com/Products/De...odID=EFLM4090A

Got the prop on backwards?

[rcers]

Sounds right on to me.

17x8 prop is not much load on 6s with that motor. It is pretty low KV. I suspect you need more pitch and prop. And you will want a bit more power - for sure.

Mike

[wilinfla]

Originally Posted by rcers

Sounds right on to me.

17x8 prop is not much load on 6s with that motor. It is pretty low KV. I suspect you need more pitch and prop. And you will want a bit more power - for sure.

Mike

Mike,

Thanks, the prop is on correctly. The 17 is about the largest that I can go because of ground clearence issues. I would like to go to a 15 or 16 inch prop, can you recommend what pitch might work or even a 3 blade prop size? I am not concerned with top speed from this model. Thanks.

Will

[stuart]

i have the hog bipe also using eflite power 60,100amp cc ice esc,and using 6cells. also a 16x8"apc prop. gets plenty of power but not unlimited vertical.918watts and 49amps wot bench test.

the batteries i was using were zippies 4000mah 20c's for a long time,now i'm going to use 4000mah batteries only now 40c. if i really wanted better performance i could rebuild the battery box to accomidate the 4000mh 4cell with a 4000mah 40c 3cell and still use the same prop.this is my next project to do to the greatplanes extra 300s.

the power 90 does have a lower kv....go to 7 or 8cell since your esc hv will be plenty good for the eflite 90.

post a picture of your pig,i love to see it.stu

[rcers]

Agree with Stu - then more volts are in order.

Mike

[wilinfla]

I would like to stay with 6S. Could you recommend a motor and prop set up that might work?

Will

[kyleservicetech]

Originally Posted by wilinfla

I am finishing up a conversion of my Sig Astro Hog Bipe to electric power. I have the following system in it. E-Flte 90 motor, Castle Ice HV120 ESC, Thunder Power 6S,3850mah, 45C battery. I have a 17/8 APC prop on it. When I ran a check with my wattmeter it shows 33 amps at 750 watts. Does that seem low? The plane will be 7.5 pounds so this gives me 100 watts per pound, I just thought I would see more power from this combo.

Will

Yeah
I ran across this before on that E-Flite 90 in another wattflyer thread. Check out "mofosheee" in this thread.
Hacker 6S2P A123 powered Models
http://www.wattflyer.com/forums/showthread.php?t=44686

If you want to use a $$$$ motor that WILL work, check out the Hacker A50-12S motor. I've got two of them, along with an A30, two A40's, another A50-16S, and a pair of A60's.

I just moved my three year old A50-12S motor to a Hanger 9 Kantana. Prop is a 16X8, battery pack is a 6S2P A123, similar in performance to a 5S 4000 Mah LiPo. With the prop and battery the Hacker A50-12S is pulling about 66 Amps, and about 1100 Watts. It turns the prop at about 7600 RPM. I believe that A50-12S motor can handle a 6S LiPo.

Hangar 9 Kantana Model
http://www.wattflyer.com/forums/showthread.php?t=68844

What can help here is one of those computer programs such as www.motocalc.com, free for 30 days, then $39. The Hacker A50 series comes in a number of different winds, the A50-12S, 14S, 16S, as well as an A50-12L and so on. Run the various motors through motocalc, and look at motocalc's "opinions".

[wilinfla]

Thanks, I used this same set up on my Ultra Stick 60 and it flew fine. I just think that the higher drag of the bipe needs a little more power.

Will

[rcers]

Will before switching motors - you could try some other props and see what you get.

17" max but you can try the following and see what your results are:
17x10: http://www3.towerhobbies.com/cgi-bin...?&I=LXEYH1&P=7
17x12: http://www3.towerhobbies.com/cgi-bin...?&I=LXEYH2&P=7

I am not fond of 3 blades as I just feel the efficiency lacking but with a bipe all out speed is tough and they do manage thrust well. You might try some of the following:

http://www3.towerhobbies.com/cgi-bin...&I=LXNGV2&P=ML

Mike

[wilinfla]

Originally Posted by stuart

i have the hog bipe also using eflite power 60,100amp cc ice esc,and using 6cells. also a 16x8"apc prop. gets plenty of power but not unlimited vertical.918watts and 49amps wot bench test.

the batteries i was using were zippies 4000mah 20c's for a long time,now i'm going to use 4000mah batteries only now 40c. if i really wanted better performance i could rebuild the battery box to accomidate the 4000mh 4cell with a 4000mah 40c 3cell and still use the same prop.this is my next project to do to the greatplanes extra 300s.

the power 90 does have a lower kv....go to 7 or 8cell since your esc hv will be plenty good for the eflite 90.

post a picture of your pig,i love to see it.stu

Stu, here are a couple pictures of the Hog Biplane. I built it about 8 years ago, but I didn't fly it until this summer. It has a few flights on it with a nitro .65 and it flew great. I removed that since I have switched to total electric. I am going to put on some larger wheels and take it flying this weekend. I just need to finish the battery hatch. I figure with 100 watts per pound it should still fly decent, we will see!

Will

[kyleservicetech]

Originally Posted by wilinfla

Stu, here are a couple pictures of the Hog Biplane. I built it about 8 years ago, but I didn't fly it until this summer. It has a few flights on it with a nitro .65 and it flew great. I removed that since I have switched to total electric. I am going to put on some larger wheels and take it flying this weekend. I just need to finish the battery hatch. I figure with 100 watts per pound it should still fly decent, we will see!

Will

Will-

What is the wingspan and wing area of your Bipe? I've got a club members Bipe in my workshop that looks very similar to your model. But, the owner has zero information on it. Like the mfg and model type, CG location or anything else.

He provided a brand new Hacker A50-12L motor and will be using a 6S LiPo in it.

Let me know, and thanks.

[wilinfla]

The top wing is 55" and the bottom wing is 52". It uses dual aileron servos for the bottom wing and uses control rods to connect them to the top wing ailerons. If you need anymore infoormation, let me know. I still have the manual and plans for the Hog Bipe.

Will

[wilinfla]

Originally Posted by kyleservicetech

If you want to use a $$$$ motor that WILL work, check out the Hacker A50-12S motor. I've got two of them, along with an A30, two A40's, another A50-16S, and a pair of A60's.

I just moved my three year old A50-12S motor to a Hanger 9 Kantana. Prop is a 16X8, battery pack is a 6S2P A123, similar in performance to a 5S 4000 Mah LiPo. With the prop and battery the Hacker A50-12S is pulling about 66 Amps, and about 1100 Watts. It turns the prop at about 7600 RPM. I believe that A50-12S motor can handle a 6S LiPo..

I looked at the Hacker A50-12S V2 and it shows max amps at 70 and max watts at 1250 running on 6S with a 14x7 prop. That would be perfect for what I want I think. I may have to put that on my wish list!

Will

[kyleservicetech]

Originally Posted by wilinfla

The top wing is 55" and the bottom wing is 52". It uses dual aileron servos for the bottom wing and uses control rods to connect them to the top wing ailerons. If you need anymore infoormation, let me know. I still have the manual and plans for the Hog Bipe.

Will

Thanks Will
No match, this one is 52 inches and 49 inches.

DennyV

[stuart]

will,she's a beauty!! how are you loading the battery? i did a hatch under the nose where the tank would be and made a scoop to vent the fuse compartment. i also put in an arming plug/switch so if i load up the batts and plug them in i could wait to arm the system if to many guys were flying at once.

i'v built 2 hog bipes and the second pig is doing very well on 6cell.

2 pics of both hogs.....

[dgholmes59]

I put your plane into webocalc and got the following result.

All up weight: 120 oz
Biplane
Wingspan: 54.5 in
Wing area: 966 sq in.
Motor kV: 325

WebOCalc Results:

Slow sport aerobatics
The following were the recommended props

APC-TE 16x10 prop
56.8 mph

Flies Like: Advanced Glow Trainer.
Power Level:
(with 16 x 10 prop) Excellent. Long vertical lines.
Might hover. 5962 rpm
Thrust/weight about 1.0:1
Minimum Battery Size: 6S, 3000 mAh, 13 C, lithium polymer.
Estimated Flight Duration: 8 to 13 minutes depending on pilot.
Suggested ESC Rating: 45 A to 52 A.
Power Into / Out of Motor: 745.2 watts in / 633.4 watts out.
Power To Weight Ratio: 99.36 watts/pound.
Estimated Stall Speed: 20.7 mph.
Wing Loading: 17.89 oz/square foot.
Cubic Wing Loading: 8.08 oz/cubic foot.


APC-TE 17x10 prop
56.8 mph

Flies Like: Advanced Glow Trainer.
Power Level:
(with 17x10 prop) Excellent. Long vertical lines.
Might hover. 5964 rpm
Thrust/weight about 1.2:1
Minimum Battery Size: 6S, 3300 mAh, 13 C, lithium polymer.
Estimated Flight Duration: 7 to 11 minutes depending on pilot.
Will vary with throttle usage.
Suggested ESC Rating: 57 A to 66 A.
Power Into / Out of Motor: 950.4 watts in / 807.8 watts out.
Power To Weight Ratio: 126.72 watts/pound.


Fast sport aerobatics:
APC-TE 16x12
67.9 mph

Flies Like: Advanced Glow Trainer.
Power Level:
(with 16x12 prop) Excellent. Long vertical lines.
Might hover. 5943 rpm
Thrust/weight about 1.1:1
Minimum Battery Size: 6S, 2500 mAh, 17 C, lithium polymer.
Estimated Flight Duration: 5 to 9 minutes depending on pilot.
Will vary with throttle usage.
Suggested ESC Rating: 53 A to 62 A.
Power Into / Out of Motor: 885.6 watts in / 752.8 watts out.
Power To Weight Ratio: 118.08 watts/pound.

[wilinfla]

Thanks for the WebOCalc results, those are really great and they will be very helpful.

Stuart, I have a hatch on the top of the fuselage just forward of the cockpit. You can see the hatch location in the photos, I haven't finished it yet. I built a box to load the batteries at an angle so they are easy to get in and out. I cut cooling slots on the bottom of the fuselage for the air to exit. The color scheme on your Hog looks fantastic, I really llike the orange.

Will

[Dereck]

Will
Been a while since I electrocuted a glow kit, but the prop size business is always an issue. For an early example, my Sig Four Star 40, which would have flown pretty good on a 40 glow lump and a 10 x 6, ended up with a 15 x 10 doing all of 7000RPM flat out, but it was enough power for a knife edged loop from, and back to, level flight.

As you've got a fair amount of loot and effort in this Hog, check out figuring out a prop dia/pitch that will really deliver from your motor/battery, then figure out an undercarriage that will clear the prop. I've used 'TnT Landing Gear' custom alloy gear several times and found their quality and service good at reasonable prices.

Their website is www.tntlandinggear.com

Lovely model, definitely one to put some effort into getting things correct, it'll fly great.

Dereck