HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Mar 07, 2013, 05:03 PM
Fly Straight Fly High
tengarang's Avatar
San Jose, California
Joined Aug 2010
3,504 Posts
Quote:
Originally Posted by anlucas View Post
The tests on my 10blade with a 4000kv outrunner on a good 4S battery where very good - in excess of 670gr of thrust for around 30amps. Only problem is the battery needs to be good - 45c at least.

My main problem is that there is a significant (20-25%) drop in static thrust when the fan is fitted in the airframe.

I, too hope that the inrunner will be a better performer.
Hi anlucas,

despite youre running a 1000KV less outrunner ...your still drawing more current...thanmy 4100KV with presumably more thrust...well I did run a lower C rated battery ... still there is still quite a bit of buffer zone.

My hopes like yours the inrunner will show some relief
tengarang is offline Find More Posts by tengarang
Reply With Quote
Sign up now
to remove ads between posts
Old Mar 07, 2013, 05:29 PM
check for reversed controls
alpea 41's Avatar
United States, CA, Chino
Joined Oct 2007
9,922 Posts
I go away for a few days and you guys are yakking it up like women. lol
I liked the Gripen video. BTW
Every body bragging about their Screamers ... I gotta show my scratch built. I think it has the potential for many mods ,
and a few crashes.
It's 99 cent store and Dollar market building materials.
Any way I'm thinkin it came out good.For $8. bucks Mico Wemo , Het Motor 4s any size I want

And I cant seem to down load pics I feel like a proud Granpa
alpea 41 is online now Find More Posts by alpea 41
Last edited by alpea 41; Mar 07, 2013 at 05:50 PM.
Reply With Quote
Old Mar 07, 2013, 05:42 PM
Registered User
Arxangel's Avatar
Bulgaria, Sofia-grad, Sofia
Joined Feb 2012
1,583 Posts
Quote:
Originally Posted by mopetista View Post
Reading this thread you must get the impression that only 300+ Watts will get your jet moving, IMO they already rock bone stock if you use light batteries.
Actually I am not getting that impression. I have a stock T-45 and after I balanced the impeller I am pretty sure it has much more thrust. I am running it on a 3S Nano-tech 1000mAh 45C so it is still some 30 grams heavier than it would have been had I gone for the recommended 850mAh. It does need just a tad more thrust or a little less weight to get a good vertical. Otherwise, when you max the throttle it does go vertical quite well until it looses speed and levels off.

Quote:
Originally Posted by GTrain View Post
Is the Dr Mad Thrust 10blade specifically for 4s? Has anyone had any experience with the Fan/Motor combo for 3s?
I would also like to know the answer to that question!
Arxangel is online now Find More Posts by Arxangel
Reply With Quote
Old Mar 07, 2013, 05:44 PM
chuck
santa barbara, CA
Joined May 2009
3,964 Posts
Quote:
Originally Posted by anlucas View Post
No I am not. The AMX seems to have a pretty clean and short exhaust so didn't want to add more weight that far back.
agreed, the amx stock has the perfect exit diam for stock and 6 blade fsa.
chas650r is online now Find More Posts by chas650r
Reply With Quote
Old Mar 07, 2013, 05:47 PM
chuck
santa barbara, CA
Joined May 2009
3,964 Posts
unless you guys have overloaded motors u will find little difference between in and out runners, sorry no magic pill
chas650r is online now Find More Posts by chas650r
Reply With Quote
Old Mar 07, 2013, 06:05 PM
Registered User
Vienna, Austria
Joined Apr 2007
1,878 Posts
Lander 10-blade 3300kV combo: only 4s?

well, we have recently discussed this here already, but once again:
- it draws around 27A on 4s (measured, using a good 1000mA high C-rating)
- it draws around 18-20A on 3s on a fresh lipo (20 measured on big fresh 3s)
so it will be just a bit higher power on 3s than the stock unit, however it is 50g heavier, and you can expect that the high blade-count fan being less efficient than a 5-blade or 6-blade so on 3s you end up with similar thrust than stock and 50g more weight, which is around 15% (!) more than your typical (light) stock Sky Angel plane.
Now there is no definite answer if it is "good for 3s" or not, it's up to you to decide if that suits your needs and flying style. No performance upgrade for sure, but it should be a sound upgrade. (Well, and in the Mirage or in the Gripen some of the higher weight would be welcome since CG is impossible to obtain even with 850mA 3s all the way back. Since one would have to mod the fan area anyway one might then put it further back and be able to then move the lipo around in front for best CG)
The full potential of the fan, at only a little more weight (in case of a small 4s lipo) you will have on 4s. I might try 3s some time, but there are other projects I want to do first.
cheers
Clemens
mopetista is online now Find More Posts by mopetista
Last edited by mopetista; Mar 07, 2013 at 06:16 PM.
Reply With Quote
Old Mar 07, 2013, 06:09 PM
Chino Renegade oh-gee, yo
Wrench66's Avatar
United States, CA, Chino
Joined Feb 2008
2,528 Posts
Nice Delta Pool Noodle 50mm, Al!
Wrench66 is online now Find More Posts by Wrench66
Reply With Quote
Old Mar 07, 2013, 06:17 PM
Registered User
Vienna, Austria
Joined Apr 2007
1,878 Posts
Quote:
Originally Posted by Wrench66 View Post
Nice Delta Pool Noodle 50mm, Al!
+1 - and a great name: DELTA POOL NOODLE 50 :-)
mopetista is online now Find More Posts by mopetista
Reply With Quote
Old Mar 07, 2013, 08:45 PM
Registered User
Mike20's Avatar
Joined Sep 2012
544 Posts
I found the mini concept x motor that i believe is the 5800kv motor that I have in my f18. It has the same size bullet connectors as the one I have had. So Im assuming its the right motor.

http://www.nitroplanes.com/69a501-09-motor.html
Mike20 is offline Find More Posts by Mike20
Reply With Quote
Old Mar 07, 2013, 10:04 PM
Registered User
Joined Nov 2012
388 Posts
everybody has to remember that thrust and amp numbers are not enough to tell the performance. you also have to know the efflux speed.
a 13x4 prop and a 6x6 prop may produce the same static thrust numbers but, they will propell a plane at very different speeds. the more blades you have, will act like a bigger prop. a 4 blade edf with the same thrust as a 10 blade will have higher efflux and thus more top speed
rcfisherman is offline Find More Posts by rcfisherman
Reply With Quote
Old Mar 07, 2013, 10:44 PM
Fly Straight Fly High
tengarang's Avatar
San Jose, California
Joined Aug 2010
3,504 Posts
Quote:
Originally Posted by rcfisherman View Post
everybody has to remember that thrust and amp numbers are not enough to tell the performance. you also have to know the efflux speed.
a 13x4 prop and a 6x6 prop may produce the same static thrust numbers but, they will propell a plane at very different speeds. the more blades you have, will act like a bigger prop. a 4 blade edf with the same thrust as a 10 blade will have higher efflux and thus more top speed

Sounds like we need to take EVERY model Truth back to the highschool college days.....to Eflux and amp test everything.....to repor the truth....

This will take more than a few systems equations...but more of a matter of Hull calculations and initial velocity thrust in conjunction of airframe resistance analysis...

OR we can just do simple estimates by data and report results here...
tengarang is offline Find More Posts by tengarang
Reply With Quote
Old Mar 08, 2013, 12:24 AM
222 km/hr Parkjet flyer
solentlife's Avatar
Latvia / UK visits
Joined Jan 2010
8,335 Posts
Quote:
Originally Posted by chas650r View Post
unless you guys have overloaded motors u will find little difference between in and out runners, sorry no magic pill
Very true .... I've run both Out and In runners .... both up to 5000kv formats .... difference ? Haven't been able to detect significant benefit other than slimmer motor body allowing exhaust flow of fan to be cleaner / less obstructed with the inrunner.
Whatever you do ... it all still obeys Physics Laws ... you don't get anything for nothing. You may gain a little by increasing efficiency of motor by a few % points - but that's it.

In my view - the biggest gains are got by :

a) Better battery to provide the power needed
b) Clean efficient ducting.

Nigel
solentlife is offline Find More Posts by solentlife
Reply With Quote
Old Mar 08, 2013, 12:44 AM
Registered User
Vienna, Austria
Joined Apr 2007
1,878 Posts
EDFs are pretty much unlike prop drives...

Quote:
Originally Posted by rcfisherman View Post
everybody has to remember that thrust and amp numbers are not enough to tell the performance. you also have to know the efflux speed.
a 13x4 prop and a 6x6 prop may produce the same static thrust numbers but, they will propell a plane at very different speeds. the more blades you have, will act like a bigger prop. a 4 blade edf with the same thrust as a 10 blade will have higher efflux and thus more top speed
all the EDF guys will tell you that this does not apply to EDFs - and they are right, at least for long thrust tubes when the speed of the air particles is evened out (pretty much). Then, it is only relevant how big the exit diameter, and how much thrust. From that you can also calculate efflux speed, average efflux speed to be more precise.
That is why nobody even talks about blade pitch etc. as far as EDFs are concerned. For shorter thrust tubes this applies not 100%, but still you will see that there is not sooo much difference. Definitely very different from props, and you will also not see unloading, i.e. amps going down in flight, like with the prop planes.
HOWEVER a big difference, it turns out, lies in how different fans cope with, e.g., restricted intakes (when they have to literally "suck" the air), and restricted exits (the smaller the exit, the more back pressure, and some of the higher blade-count fans with high aspect ratio blades then show stall behaviour with dramatically reduced thrust). There was a lot of new experience with the 70mm and 90mm Change Sun fans, however some rules still apply - in their domain.
So in the end it is still best to try every fan in every model, and there can be surprises, but not because of some efflux which is much higher than thought from the thrust figures, or vice versa...
mopetista is online now Find More Posts by mopetista
Reply With Quote
Old Mar 08, 2013, 02:40 AM
Has Sloped Off
dav3uk's Avatar
Uk South Wales
Joined Aug 2009
2,262 Posts
When I first got my F9F it was my first Ducted fan for a long time, the last being a Byron F16 a million years ago......lol. But I did what I thought was best and used the best practice from the old days and sanded the duct smooth, removed the sharp corners etc, then tidied the wires, balanced the fan made sure it wasnt deformed when tightening the hatch, all the things I thought would make mine just a bit better.

Well what was the result.............nothing, when I bought the plane I got 2, 1 for me and 1 for a mate and he just bunged the lipos in and flew it. In the air together there is nothing between them, same plane/motor/esc/lipo............

So at that point I went thrust tube route and reduced the tailpipe diameter by about 6mm...........now he cant catch me.....result

I think the small size of these plane produces quite inefficient ducting anyway and the small changes I made just were not significant, on larger diameter fans it may come into play more.

It suprised me as I would have thought that small diameter lower power setups like these 50mm models would respond to saving every % of power possible.

I think the best route for speed/performance is a low balde count wide blade fan just to get as much air volume through as possible.

Its amazing that these little jets go so well and are so cheap compared to the $1000s of dollars spent on Byron stuff

Of course they were gas but were putting out 3000-5000w (4-6.5hp)

Just my observations and memories
dav3uk is offline Find More Posts by dav3uk
Reply With Quote
Old Mar 08, 2013, 03:23 AM
efflux RC's Avatar
United States, CA, Santa Clarita
Joined Aug 2009
8,440 Posts
Love the Noodle Delta Al !!.
efflux RC is offline Find More Posts by efflux RC
Site Sponsor
Latest blog entry: Updated blog Jan 2014
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Adelaide & SA flying & chat #2 Zootster Australia 19870 Today 08:20 AM
Help! Where can I buy Genkem Nova 27 in SA? MegaTesla South Africa 2 May 14, 2011 03:25 PM
Discussion SAL-SA Glider in Gobi dune romanticus Slope 11 Nov 30, 2010 10:40 PM
Question SA 2010-02 Castle ICE 100 "failed cut off" ?? LandCruiser Castle Creations 2 Oct 19, 2010 11:07 PM
T-33 Spring-air minis HW609 Derrek Curtis Electric Ducted Fan Jet Talk 3 Apr 25, 2001 03:42 PM