100 lb plane

[rcman]

Hey Guys,
I am in need of some help. I have a buddy that would like to make a Bill Hemple 60% Extra electric.

Have any of you came across a motor that would power that?

David Olsen

[blucor basher]

For sport flying, at least, plettenberg has products that would do it. For ripping 3D vertical....that's going to be an interesting project.

[blucor basher]

BTW, is there a budget? Or is the sky the limit?

[Z06kal]

Something like a Hacker A150 and a Jetti SPIN 200 are good for an 8kw power system. That will be in the ball park of 50-55 pounds of static thrust (at WOT which the system won't handle continuously). This will fly the model fine but power ratio will be closer to a full scale Extra making 3d impossible (as it is on the real extra).

[MCarlton]

One of the Neu 2230 series might do it at 10kw.

http://www.neumotors.com/Site/2200_series__.html

Can also be geared 6.7:1, so potentially, a big low pitch prop can be swung?

OR...

Why not gear 2 motors together? I know you'd lose something in the gearbox, but thinking about it, no reason 2x 10Kw motors could not be geared to a common shaft.

20,000 Watts should be enough? 27Bhp more or less ;)

[Geoff Dryer]

Field charging the Lipos should be interesting....

[rcman]

Thanks guys for the help and input.

No the budget is not limited because he is crazy!!! For what I have found it seems that there is some motors that would work. The problem is the ESC, there really is not anything that can handle that much power. Well that much power to 3D the plane.
Maybe the answer for the ESC problem is to gain two motor togather with two ESC geared to one output shaft. What do you think?

David Olsen

[bsipro]

Check out Castle Creations they have comercial ESC that might work you will need to call them though
good luck

[blucor basher]

Maybe the answer for the ESC problem is to gain two motor togather with two ESC geared to one output shaft. What do you think?

Yeah, that's how it has been done in the past.



http://www.composite-arf.co.uk/images/Kd89355.jpg

[Z06kal]

Well I believe hacker made a gearbox that took 4 C50's together..... I guess if you can find the right gear box or design your own.... Two NEU BAM's would do the trick yielding 20kw.... And I know scoprion is releasing a very powerful ESC sometime early next year.

[Thekid3418]

Suppo has listed on their site a 200 amp 15s capable ESC, but no one carries them that I know of. Its something you could look into...

[gyrokiteguy]

I am certainly no expert in these matters, but I've got some thoughts based upon a bunch of reading on how to electrify large glider towplanes.

Most planes need about 50 watts per pound to just fly. You will need 150 to 250 watts per pound for performance, but that will be only for burst periods, not continuous.

100 pounds x 50 watts/ lb = 5 Kw.
100 pounds x 150 watts/lb = 15 Kw.
100 pounds x 250 watts/lb = 25 Kw.

If I were you, I'd use two or three of these dual shaft motors, coupling the output shaft of one motor into the back shaft on the next motor. You could then use double or triple ESCs and have the advantage of redundancy without having to fool around with a gearbox.

http://www.hobbycity.com:80/hobbycity/store/uh_viewItem.asp?idProduct=5141&Product_Name=HXT_80-85-B_170Kv_Brushless_Outrunner_(eq:_70-40)
http://www.hobbycity.com:80/hobbycity/store/uh_viewItem.asp?idProduct=5139&Product_Name=Turnigy_80-100-A_180Kv_Brushless_Outrunner_(eq:_70-55)
http://www.hobbycity.com:80/hobbycity/store/uh_viewItem.asp?idProduct=5142&Product_Name=Turnigy_80-100-B_130Kv_Brushless_Outrunner_(eq:_70-55)

Hobby City used to have several other large HXT outrunners, but they seem to be removed from their offerings right now.

3 x7 Kw motors would run cool when cruising and give 20+ Kw burst power.

$100 motor + $75 ESC = $175 per power unit x 2 to 3 units = $370 to $525 for motors and ESCs.

4 or 6 of these batteries at $80 each would do the trick: (6S1P @5000 mah)
https://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7639

Thus $320 to $480 for batteries.

Thus $700 to $1000 for the entire power train, plus motor mounts and shaft couplers. It sounds like a lot of money, but a DA150 or larger isn't cheap either. A DA150 is "only" 10 Kw or so too.

Keep us informed as to how you make out so that we can learn too.

[blucor basher]

Yeah, if you decide to power your $10,000 project with HXT motors, keep us informed as to how that works.

[gyrokiteguy]

I think I sense some sarcasm in that comment. In the defense of my recommendation, some people have had really good luck with those motors.

If I had the choice of selecting big dollar, big name motors and not doing the project or doing it with lesser brand motors, I'd take the later.

[Geoff Dryer]

Maybe it is worth giving Steve Neu (Neu Motors) a call to see if he can build you a multi-motor unit. Multiple ESCs is likely the easiest solution. The Neu motors are also relatively light. This will be necessary as you are likely going to need 2 sets of 12S-2P 5000s (total of 8 batteries) in order to get any performance. Interesting project.

[MCarlton]

Schulz do a 400 Watt capable ESC, for 14Cell LiPo packs.

http://www.schulze-elektronik-gmbh.com/index_uk.htm

Expensive though at about $900 a throw

[Boomerang1]

http://www.sonexaircraft.com/index.html

is the link to Sonex Aircraft. They built a full size electric powered aircraft & from what I remember Astroflight designed the electric setup.

For such a large project you may be better off engineering down an existing set up rather than trying to design up from model systems.

http://gas2.org/2009/06/18/100-electric-airplane-sets-new-world-speed-record/

Interestingly, the above is a link to a flight by a full size electric aircraft to set the world speed record for the type, the race is on! - John.

[paintball_kidz]

Most planes need about 50 watts per pound to just fly. You will need 150 to 250 watts per pound for performance, but that will be only for burst periods, not continuous.

100 pounds x 50 watts/ lb = 5 Kw.
100 pounds x 150 watts/lb = 15 Kw.
100 pounds x 250 watts/lb = 25 Kw.


You'll only need 150-200 watts/lb 250 would be over kill, i would personly go with 18kw of power for that

[Magne]

"You'll only need 150-200 watts/lb 250 would be over kill, i would personly go with
18kw of power for that"

In which case we are back to off the shelf model airplane stuff:
Plettenberg Predator 37-6 motor
Jeti Spin 300 regulator
14s lipos