SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Jun 19, 2011, 03:32 PM
Team Hillbilly
tominator06's Avatar
United States, MD, Dundalk
Joined Feb 2009
3,492 Posts
Here is a run up on the Watts-Up meter. Turnigy 4s 40c 2650 lipo, Turnigy Aerodrive Xp 3548-900kv, Turnigy 60A Superbrain Esc

Apc 13x6.5 prop

Eflite Yak 54 Carbon Z - Turnigy 3548-900kv 13x6.5 prop Watts-Up test (1 min 7 sec)
tominator06 is offline Find More Posts by tominator06
Reply With Quote
Sign up now
to remove ads between posts
Old Jun 19, 2011, 03:39 PM
Registered User
xxxcellarator's Avatar
Toronto, Canada
Joined Nov 2009
657 Posts
Quote:
Originally Posted by tominator06 View Post
Lol I'm not running the same motor I don't think. You mentioned running the 3648 and I am running the 3548 aerodrive xp. I am charging a pack now to test with though. What kv are you running?
Oh sorry, I read through your comments too quickly Yea, we're not running the same motors. Although they are not very different at all.

I'm running the 3648-850kv. This one: http://www.hobbyking.com/hobbyking/s...idProduct=8486

You're running this one: http://www.hobbyking.com/hobbyking/s...idproduct=7393

Considering they have almost the same KV rating, I think you should be able to get the same numbers. If you have the battery for it, I'de go 5s on that motor. If you don't then I'de step it up to a 14 inch prop Although ground clearance might be a pain in the arse.

And yeah, my tests are done the same as yours. Static on the ground with a watt meter (using the Turnigy watt meter), on a 100% fresh battery. I like doing the tests like this since they are consistent for comparison purposes, and they are pretty much worse case scenario anyways. That 35-48 you have can EASILY be pushed to 1000watts +. If it were me, I'de push it as far as 1200 watts on a fresh battery. I've put over 50 flights on a 35-42-1250 SK motor that's pushing about 950 watts on a fresh battery. Motor still sounds and runs amazing, and it comes down COLD after every run. And this is the 42m which is smaller than your 48 and only rated for 630watts.
xxxcellarator is online now Find More Posts by xxxcellarator
Reply With Quote
Old Jun 19, 2011, 03:43 PM
Registered User
xxxcellarator's Avatar
Toronto, Canada
Joined Nov 2009
657 Posts
Quote:
Originally Posted by tominator06 View Post
Here is a run up on the Watts-Up meter. Turnigy 4s 40c 2650 lipo, Turnigy Aerodrive Xp 3548-900kv, Turnigy 60A Superbrain Esc

Apc 13x6.5 prop

http://www.youtube.com/watch?v=8F_9r9p98zA
Just watched your vid. Yeah 850 watts, not bad. Could definitely push it much harder if you wanted to though. That's all I'm saying. I pushed my 35-42s harder than that.

BTW, forgot to answer your question on ESC, I'm using a Hobbyking 60-70 amp ESC. And the batteries are Zippy Flightmax 2200mah 5S 40-50c.
xxxcellarator is online now Find More Posts by xxxcellarator
Reply With Quote
Old Jun 19, 2011, 03:56 PM
Team Hillbilly
tominator06's Avatar
United States, MD, Dundalk
Joined Feb 2009
3,492 Posts
I may end up trying a 13x7 or even a 13x8 on it. She seems to get pretty warm and is very noisy. I suspect the bearings are going. I will have to replace them before I push any harder. Xoar makes some very good electric wooden props. They out perform the apc but are twice the price. They are also not as forgiving of light strikes. I have a couple ordered for my extra shp balsa plane. I want to see how they are.
tominator06 is offline Find More Posts by tominator06
Reply With Quote
Old Jun 19, 2011, 04:45 PM
Registered User
xxxcellarator's Avatar
Toronto, Canada
Joined Nov 2009
657 Posts
Quote:
Originally Posted by tominator06 View Post
I may end up trying a 13x7 or even a 13x8 on it. She seems to get pretty warm and is very noisy. I suspect the bearings are going. I will have to replace them before I push any harder. Xoar makes some very good electric wooden props. They out perform the apc but are twice the price. They are also not as forgiving of light strikes. I have a couple ordered for my extra shp balsa plane. I want to see how they are.
I've had plenty of noisy bearings in the Turnigy motors. But I've never had any of them give up on me. Although I do oil them once in a while. Especially when I hear them get noisier than before.

As regular maintenance, I oil them just about 20-30 flights (battery packs).

Why do you want to go with a higher pitch? Youre not going anywhere in a hurry with this plane, and adding pitch will only lower your thrust at a cost of higher consumption. You won't have the same power to keep up your harriers and hovers either.

Only go with a higher pitch if you want more speed. otherwise it'll do nothing but harm.
xxxcellarator is online now Find More Posts by xxxcellarator
Reply With Quote
Old Jun 19, 2011, 04:56 PM
Team Hillbilly
tominator06's Avatar
United States, MD, Dundalk
Joined Feb 2009
3,492 Posts
Yeah I guess your right. I just tweaked a little and went out for another flight. I have plenty of speed once it gets up there. Actually it's probably as fast or faster than stock once it gets rolling. I struggle for straight up vertical pull out of a hover still. This time the esc got pretty warm and the motor got hot. I didn't bring the temp gun with me but 3-5 minutes later back to the shop and the motor was 150f still. esc was ok @ 115f and the battery was about 115f as well. Video will be uploading in a few minutes. I want the vertical and could care less about top speed. I think 14" prop would be pushing it as far as clearance with this plane unless I removed the wheel pants and put bigger tires on it.

I didn't realize how fast it was till I let it get going and ran it out a little.
tominator06 is offline Find More Posts by tominator06
Reply With Quote
Old Jun 19, 2011, 05:32 PM
Team Hillbilly
tominator06's Avatar
United States, MD, Dundalk
Joined Feb 2009
3,492 Posts
Little better this flight. I am amazed at how fast this thing snap rolls. Very impressive. The more I fly it the more daring I will get. I did oil the bearings and tighten the prop. It seems quieter than the first flight for sure. Little worried about the heat but I think this setup is close to what I want for now. I wish it had a tad more pullout from hover. Probably the only way I will get it with this motor is to try 5s. Not sure I want to go there but you never know. I guess since nobody wants to to buy it I will just keep it and fly her. It is a great plane!!

Eflite Yak 54 Carbon Z - Turnigy power setup - Test 2 (5 min 27 sec)
tominator06 is offline Find More Posts by tominator06
Reply With Quote
Old Jun 19, 2011, 07:21 PM
Registered User
xxxcellarator's Avatar
Toronto, Canada
Joined Nov 2009
657 Posts
Ok, let me try and explain something. See... Normally, you would use a high pitched prop on a fast plane, or any sort of plane that you would fly fast. Basically a plane that you wouldn't be doing stall moves with, such as the Yak there the plane is hanging by the prop. So what happens is that the plane moves really fast as a result of the high pitch of the prop and therefore the high speed air passing through the motor cools it down.

When your doing a lot of hover moves, and slow moves, the plane fights against the pitch of the prop and does not let it unwind. In addition, because you have a higher pitch, as i mentioned before, you are losing thrust. This means that the motor has to work EXTRA hard to pull the plane. Add in the fact that the plane isn't moving at a high speed to get that cooling airflow, and ur power system will of course get hot.

Basically, when your using a high pitch prop and flying a 3D plane doing stuff like hovers, your using 500watts to keep the plane up instead of using only 200watts with a larger prop with smaller pitch, because the prop is inefficient for what you're trying to do with it.

The same thing happens with a high speed plane with a very large prop. Picture something like a funjet with a 10inch prop (hypothetically). The prop would consume an extreme amount of power, but the pane would still be extremely slow. Because the prop is producing a crap load of wasted thrust that the plane doesn't need. At the same time it isn't moving fast enough to get the airflow into the motor. And it would end up heating up.


Hope that helps
xxxcellarator is online now Find More Posts by xxxcellarator
Reply With Quote
Old Jun 19, 2011, 07:35 PM
Team Hillbilly
tominator06's Avatar
United States, MD, Dundalk
Joined Feb 2009
3,492 Posts
Ok so speed is unneeded here and I want to stay with 4s if possible. Do you think the 13x4 prop would work better? I am assuming the 13x4 with only 900kv wouldn't be enough for decent hovers and stall maneuvers. I guess 14" prop or 5s is the only choice with this setup. I wish I had purchased a different motor now.

I see xoar makes a 14x4 prop. Maybe I will try one of those and a slightly larger set of wheels.
tominator06 is offline Find More Posts by tominator06
Last edited by tominator06; Jun 19, 2011 at 07:56 PM.
Reply With Quote
Old Jun 19, 2011, 08:25 PM
Registered User
xxxcellarator's Avatar
Toronto, Canada
Joined Nov 2009
657 Posts
Actually the 13x4 probably wouldn't be a bad choice. It also depends on how you'de like your plane to perform. If you're happy with how it flies overall at the moment, then why bother changing it.

On that note, what the 13x4 is going to do over the 13x6.5 is, it will increase you're thrust and lower your power, therefore decreasing your Wattage and Amps. The plane will fly for longer and get much less hot. However, it will also be much slower as far as top speed. Going to a smaller pitch prop is virtually exactly the same as lowering the gearing on a car or bike. You get a lot more Torque and the motor has to work less, but you loose top speed. This means that hovers will be much easier and the plane will pull out much quicker (quicker acceleration).

As far as what motor you got, the stock motor is rated for 1000kv. Therefore, because you went with lower KV, ideally you should have also gone up in battery voltage (cell count). Or, a better choise would have been the 1100kv version of your motor. Then the 13x4 would have been perfect.

I'de suggest trying out a 13x4 and see how you like it. Unless you can go with a 14inch prop. You'll have to be really carefully on landings with that prop though.

P.S. you can also find 13x5 props if you don't want to step down in pitch too much.
xxxcellarator is online now Find More Posts by xxxcellarator
Reply With Quote
Old Jun 19, 2011, 08:29 PM
Registered User
xxxcellarator's Avatar
Toronto, Canada
Joined Nov 2009
657 Posts
Oh one more thing, try the Highest timing on your ESC if your not already using that. These SK motors really like high timing. Although if you're already getting really hot, that might not be such a good idea.
Also, here's some data on your motor: http://bungymania.com/imageshome/inc...erf1.php?id=73
The planes they use for testing are not 3D planes, but at least you can see the figures on different props and batteries for reference. As you can see the 11x5.5 prop on 5s gives almost the same Thrust as the 13x6.5 on 4s, yet it is faster. It will also run cooler. Too bad they didn't try a 13x4 0 or 13x5.
xxxcellarator is online now Find More Posts by xxxcellarator
Last edited by xxxcellarator; Jun 19, 2011 at 08:35 PM.
Reply With Quote
Old Jun 19, 2011, 09:06 PM
Team Hillbilly
tominator06's Avatar
United States, MD, Dundalk
Joined Feb 2009
3,492 Posts
Thanks for all the insight. I have a basic idea whats what but sometimes I just have to see for myself how things work. I also like to post videos on youtube for the world to see. On another note it's funny that these are the exact same props I am running in my 47" 3dhobbyshop extra 300 shp on 3s with a castle ice 50 esc. I already have 2 xoar 13x5's ordered for that plane. LOL I actually got a little too hot of a setup in that one with the new Motrolfly custom wound motor which is 1025kv instead of the 900kv I had in it. I was running the 13x6.5 but now it is pushing the limits of my batteries and esc. I am pretty happy with the 13x4 on it but ordered the xoar 13x5 to see how they fly. I have lots props hanging around these days. 12x6, 12x8, 13x4, and 13x6.5 atm and a few nip of stock eflite yak props which are useless to me now. I'll get it figured out.
tominator06 is offline Find More Posts by tominator06
Reply With Quote
Old Jun 19, 2011, 11:03 PM
smoke is my wattmeter
Longview, Tx
Joined May 2008
1,139 Posts
Here's my motor http://www.hobbypartz.com/86mb29-roc...26-1130kv.html I spooled it up with a 12x6 APC E prop and it sucked 690 watts with a full Gens Ace 2200 25c 3s, about 600 with a 13x4. Still waiting on dang servos to get here.
krexken is offline Find More Posts by krexken
Reply With Quote
Old Jun 19, 2011, 11:26 PM
Team Hillbilly
tominator06's Avatar
United States, MD, Dundalk
Joined Feb 2009
3,492 Posts
How many amps?
tominator06 is offline Find More Posts by tominator06
Reply With Quote
Old Jun 19, 2011, 11:33 PM
smoke is my wattmeter
Longview, Tx
Joined May 2008
1,139 Posts
Think it was 59 with the 12x6 on there.
krexken is offline Find More Posts by krexken
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold E-flite 4-Site like new BNF Version MK2 Aircraft - Electric - Micro & Indoor Airplanes (FS/W) 1 Sep 30, 2010 07:51 PM
Discussion Why Not wood -balsa BNF or PNP RC airplanes from E-flite? MerlinKing Parkflyers 3 Jan 20, 2010 09:45 PM
Discussion Why Not wood -balsa BNF or PNP RC airplanes from E-flite? MerlinKing Scale ARF/RTF 1 Jan 20, 2010 07:29 PM
Alert Ikarus Yak 54 Or E-Flite Extra 260 E-Flite Sobre 3DX shocky... jamiekerr 3D Flying 15 Aug 07, 2007 01:24 PM
Poll Part of Ikarus Yak 54 Or E-Flite Extra 260 E-Flite Sobre 3DX shocky... POLL jamiekerr 3D Flying 1 Aug 07, 2007 03:55 AM