HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Aug 01, 2010, 05:46 AM
Tobias (aka glider hangaround)
Fluffracka's Avatar
Stockholm, Sweden
Joined Apr 2008
551 Posts
Discussion
Prop for a Ava?

I am a total noob when it comes to the powerpart of e-soaring, and Ive bought a used Ava-E which im in the process of puting togheter. I have installed the motor and ESC but cant find any clear answers on what prop to use, Ive searched but has not found any threads that cover my kind of drivetrain.

I would really be thankful for any input from those in the know.

Motor:
E-Max
Modell: GT 2826/05
Kv: 860
Lipocell: 3-5
Max Watt: 992 W.
Max Ampere: 54 A .
Weight: 175 g.

ESC:
Turnigy/HobbyWing
Max Amp: 60 A (Burst 80 A/10 sek).
Weight: 60 g

Lipo:
LoongMax
Volt: 11.1 V 3 cell
Capacity: 3000 mAh
Weight: 254 g.
Amp: 20 C

Plane AUW about 1500 - 1600g

Thanks in advance
Tobias
Fluffracka is offline Find More Posts by Fluffracka
Last edited by Fluffracka; Aug 01, 2010 at 06:01 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Aug 01, 2010, 06:12 AM
Registered User
fort lauderdale FL
Joined Jul 2009
144 Posts
14x10.............
andrewfl is offline Find More Posts by andrewfl
Reply With Quote
Old Aug 01, 2010, 06:33 AM
RIP Ric
Andy W's Avatar
Marietta, GA
Joined Jun 1999
43,312 Posts
That's a pretty small prop for the AVA. 17-19" would be great, but that motor is too hot for a prop of that size..
..a
Andy W is offline Find More Posts by Andy W
Reply With Quote
Old Aug 01, 2010, 10:17 AM
Registered User
martinh's Avatar
Hampshire, England
Joined Aug 2002
495 Posts
You only need about 400 watts for the AVA, so a smaller prop may be needed than the 14x10 to acheive this.

Problem is that there seems to be little info on this motor available to give an accurate estimate. If you can get the KV, Io and Rm, you can put them into a program like this one http://www.peakeff.com/GraphKIR.aspx to find the best match.

Don't worry too much about not using a 17"+ prop, plenty of people use smaller with excellent results.

Martin
martinh is online now Find More Posts by martinh
Reply With Quote
Old Aug 01, 2010, 03:56 PM
Registered User
Modesto CA
Joined Nov 2009
162 Posts
I agree with Martin 400 watts gives you about 100 watts/pound or 220 watts/kg.
My AVA E has a Neu Motor 1506 2D (5200 kv) and a 6.7 gear box that puts the shaft speed at about 776 rpm/Volt fairly close to your 860 kv. It has a 14x9 prop which draws about 40 amps at 11V. I have a 3S 3200 mah battery that gives 8 to 10 20 second motor runs. The plane leaves my hand with authority and climbs at about 3000 feet/minute.


Mac
Mac37 is offline Find More Posts by Mac37
Reply With Quote
Old Aug 01, 2010, 06:05 PM
Registered User
Modesto CA
Joined Nov 2009
162 Posts
I think I overstated the climb rate of my E Ava. I am using the CAM altitude limiter and it takes between 20 and 25 seconds to get to the 200 meter cutoff. So the absolute rate is closer to 2,000 feet/minute.
Mac
Mac37 is offline Find More Posts by Mac37
Reply With Quote
Old Aug 02, 2010, 06:53 AM
RIP Ric
Andy W's Avatar
Marietta, GA
Joined Jun 1999
43,312 Posts
So for comparison, I am putting about 500W into my AVA and get 4000fpm (just shy of 3000' in 45s), 17x13"..
..a
Andy W is offline Find More Posts by Andy W
Reply With Quote
Old Aug 02, 2010, 08:00 AM
Registered User
kilwein's Avatar
Joined Jan 2007
644 Posts
I have a multiplex 300w setup geared 3.31 with a 16x18 climbs nice but not vertical.
Have a 3300mah 3c pack for balancing and provides lots of climb outs, 58oz auw.
Going to put the eagle tree in and see climb rate this weekend.
kilwein is offline Find More Posts by kilwein
Reply With Quote
Old Aug 02, 2010, 03:42 PM
Registered User
martinh's Avatar
Hampshire, England
Joined Aug 2002
495 Posts
If you are looking to compete in the 200m height limited comps, around 2-3000 fpm is good, as it allows you to fly a decent distance upwind as well as getting to 200m within the 30 second time limit.

Not sure if the rules are the same where you live.

Martin
martinh is online now Find More Posts by martinh
Reply With Quote
Old Aug 02, 2010, 06:43 PM
Tobias (aka glider hangaround)
Fluffracka's Avatar
Stockholm, Sweden
Joined Apr 2008
551 Posts
Thanks for your input, it helped alot. Went to my LHS today and all they had on the rack that was close was a Aeronaut 14x10 so thats what I brought home. my Ava is slowly getting closer to maiden, hopefully in a few days.

Tobias
Fluffracka is offline Find More Posts by Fluffracka
Reply With Quote
Old Aug 31, 2010, 03:10 PM
Tobias (aka glider hangaround)
Fluffracka's Avatar
Stockholm, Sweden
Joined Apr 2008
551 Posts
I just want to report the result of the combination of motor, esc, propp and lipo. The lipo was changed to a 4S 2600 20C Turnigy from HC. The plane AUW ended up at 1650g.

And the drive train works great, it climbs like a homesick angel. Today i had the logger in it and it showed a climbrate of 1130 meter/minute, so Im very pleased.
Fluffracka is offline Find More Posts by Fluffracka
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Wanted Still looking for an AVA or Super AVA NOT ELECTRIC icharus Aircraft - Sailplanes (FS/W) 2 Sep 12, 2009 05:09 AM
Wanted Wanted Ava Or Super Ava icharus Aircraft - Sailplanes (FS/W) 2 Aug 27, 2009 10:48 AM
Help! Mini AVA-E prop slection Bob Cook Electric Sailplanes 29 Aug 21, 2007 08:57 PM