DaveHickey

Let me first appologize if this has been covered before, but I have searched and not found much...

Ihave been away from the hobby for 20 some years and have an unopened MK Curare 60 which (after Irefresh my piloting skills) I would like to build up as an electric powered aircraft. What I'm noticing as I research electric power systems is that brushless outrunners in the power range needed (1600-2200 watts) spin substantially larger props than the plane was designed for.Have any of you come up with a power system using an 11" (or 12" if Iabsolutely have to) prop that will fly the airplane in the manner intended for at least 7-8 minutes? Is there an inrunner that more closely approximates the power output of a piped 60 size pattern engine?

Any help appreciated... D.H.

jlingrel

I would suggest that you check with the Senior Pattern Association. They are running the old pattern planes with 90 4 strokes and running some rather large props. They are however running conventional gear, so the prop clearance may be somewhat better.

http://www.seniorpattern.com/

John

Free Bird

A good system to start with is an Eflite Power 60, 5S 4500 lipo, Castle Creations 100 amp Ice ESC.

FB

patternflyer76

Hi Dave:

I have a Pulsar biplane that I am working on that will be electric for the SPA contests. I have a 500kv motor outrunner, 80A ESC, and 6s 4000mah lipo. I have not ran tests yet, but I will let you know once I get it off the ground. 13.5x10,11,12,13,14 APC. I will start at 10 pitch and go up until the max watt limit is reached at 1400w. At 7 pounds this should put me at 200w/pound. That is 3D range which will be overkill, so a smaller prop down to 13 or 12 dia would be close as well if you keep the pitch up. I believe I will end up around the 13 pitch to get the watts out of a 13.5 dia...

Others have ran 6s/80-100A ESC/and 13.5x9 APC that I have seen perform very well.

Hope this helps:

Kevin Clark
AMA 340037
SPA 427

wildnloose

Here are a couple to get u started:

http://www.rcuniverse.com/forum/m_4978792/tm.htm


http://www.rcuniverse.com/forum/m_10303441/tm.htm

80sPattern

Dave,

I am a few months ahead of you and have gone through quite a learning process which has been documented on my Conquest IV E-Powered build thread:

www.rcgroups.com/forums/showthread.php

I decided to go with a Scorpion 4025-10 because it has a higher KV and will work with a 12" prop which I will need on my trike-geared C4.

An EFlight Power 60 or similar motor WILL NOT work for you because it is a lower KV and needs to swing a prop that is too big for your Curare.

Come on over to RC Groups and feel free to chime in. A lot of guys have been very helpful to me in my journey. This information will help you as well.

I am a few weeks away from my first flight so time will tell.

Doug

doxilia

My Feedback: (3)

Dave,

As others have mentioned, provided you keep the kV of the motor up, you will get the short stroke 60 experience turning 11" props at high rpm. At around 1000 kV motors that are rated at ~1400W will give you plenty of power. You might have to "pitch-up" to get to power but a 600 class heli outrunner on an 11x9 will have you moving out in style..

Power above 1600W shouldn't be needed on your typical 8 lb classic.

There is at least one electric Curare build on RCG. Oh, and there is an electric P8 build here using such a motor on a 10x10 prop. The plane is in the 160 mph envelope...

David

doxilia

My Feedback: (3)

By the way, note that a 1000 kV motor on 6s has it turning at ~22k rpm..., minus losses and load. This gets you in the 14k rpm ballpark - just like a piped Rossi.

David

Bozarth

My Feedback: (15)

D.H.

I am sorry to have to break the news to you, but MK Curares are no longer allowed at most locations. Please send it to me so you won't have to worry about it anymore.

Kurt

DaveHickey

In that case tell me which one you want, the 40 size or the 60 size....








Yea, fat chance, but good try...
Idid see a 60 size kit on the singapore hobby site but getting back to it might be a problem. Look at
http://www.singahobby.com.sg/mkp03.htmlwhich lists a 60 size curare kit still available but no price,
you may have to E-Mail them but if you are serious you might be able to get it. D.H.

ChiefK

Dave,

The Senior Pattern Association has in fact developed specs for the equivalent e-power system to compete in SPA contests with pattern airplanes from the 60's (including the Curare). Check out their website.

ChiefK
SPA444

turbo.gst

My Feedback: (8)

Good info about the setups - Thanks!

Trisquire

I agree that only a direct drive inrunner would turn an 11x7 at the required RPMs. It might be worth looking at motors that the electric ducted fan guys are using. They have a similar objective. To turn a small prop (or rotor) at high RPMs.

doxilia

My Feedback: (3)

Tom (I believe...)

it is not strictly necessary to use an inrunner to turn an 11" (even a 10") prop in the rpm range needed to fly a classic. An outrunner can be used too and will move the model rather fast. Here's an example of a motor that will do the job as well as a video of it flying a Phoenix 8 on a 10"x10" APC prop.

http://www.youtube.com/watch?v=2ux8s...layer_embedded

At 1100 kV, the motor will be turning very high RPM on 6s Lipo's.

David

Trisquire

Interesting. I stand corrected.

Tom

Michaelj2k

Here is the build thread. http://www.rcuniverse.com/forum/m_10303441/tm.htm Note that he did a serious airframe cleanup regarding aerodynamic drag. Who needs jets!

Trisquire

I missed the boat on that thread. And he's doing it with a $60 motor.

doxilia

My Feedback: (3)

Yea, that's what makes E-power so attractive to many. The main cost is in having a reliable ESC.

David

madcappilot

Hi Dave,I to got the idea of building a Decption and powering it with an electric but found no true comparison to the old style motor ratings.IE since when did a 61 two stroke turn a 16x8 or 40 turn a 12 to 14 inch diameter props.So i have slowly getting electric motors and trying them.What I've come up with is using a Heli 500 /600 class out runners in the kv range of 1200- 1800 if you can find them that low.I have a Castle Creations Vertigo and I was able to run it briefly until the motor mount came loose.I am using a Castle lite 75 amp speed control mainly to data record the run,a 3s 5000 30c lipo.What was recorded was an amp draw of 60 amps and an rpm of13,000 while using an 11x8.I have yet to fix the mount and mounting system to realy get a good test.Sorry for the length but this topic has been bugging me since the electrics has started thier rating system.I will next be working on a 40 setup as well for a Dirty Birdy 40.

RCDENT

My Feedback: (2)

I've looked on the SPA site and been unable to find anything about electrics. Can you post the specific link?

doxilia

My Feedback: (3)

Rules, page 2:

http://www.seniorpattern.com/pdf/SPA...02011-2012.pdf

Madcap pilot, a 3s setup pulling 60A won't cut it on 60 size pattern ship regardless of what rpm's are being pulled on a given prop. It's about power. The setup you suggest is delivering a nominal ~11.1v x 60A = 660 W suitable for a 25 size model. For a 60 size classic you're looking for ~1400 W best obtained on a 5-6s setup. 70A on 6s would be a good setup. Then, you want a motor ranked for that power with a kV rating that will turn the desired prop (e.g., 11x8) at ~15K.

For 40's you want about 1000W on a DB40 and 4-5s. Motor kV chosen for a 10x6 - 11x6 to turn 15K too. 70A on 4s would work.

David

turbo.gst

My Feedback: (8)

The electric requires power management to give acceptable flight duration. I do understand what your are trying to say about unreal prop sizes and for the most part I agree. I still think technology will get us there. I will always enjoy flying them with the period correct glow engines.

DaveHickey

MadCapPilot;

   Since opening this thread I have read a lot here and elsewhere. To answer my own question it seems that we need 1200-1600 Watts from a 700-900KV motor to turn a prop like a piped Rossi. What seems like it may work is:

   http://www.hobbyking.com/hobbyking/s...ner_700kv.html
   http://www.hobbyking.com/hobbyking/s...li_880kv_.html
   http://www.hobbyking.com/hobbyking/s...tor_800kv.html
   http://www.hobbyking.com/hobbyking/s...ter_Motor.html
   http://www.hobbyking.com/hobbyking/s..._Inrunner.html
   (BTW - I'd really like to hear your reasoning why one or the other of these might be better than the other.)

Running on a 5 or 6 cell LiPo pack, probably going to need 4-5 AH to get good duration and a 100A ESC to keep everything running cool and reliably.

Has anyone tried a similar setup and if so, how did it work out?

Dave Hickey

Bozarth

My Feedback: (15)

A large ESC won't help keep anything else cool other than itself.

Kurt

doxilia

My Feedback: (3)

Good point and a good ESC is better than a big ESC.

David