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Old Jan 21, 2013, 09:25 AM
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Joe 1320's Avatar
United States, FL, Sebring
Joined Feb 2006
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Originally Posted by metalguy View Post
Yes, the Saber will barely stay aloft, now. I have tried several different batteries, ESC's, and still just will not stay in the air. When I first put the alloy 50MM hobby king fan unit in (3s version) it worked fine. No super powerhouse, but adequate for flight. Now, it is pitiful. I have the exact same set-up in my MiG-15, and it flies beautifully, using the same batteries. So... while I didn't have any smoke leave the motor, it just has no power, and will not fly. So, I ask, is there a drop -in motor that will give this a boost on 3s? I would prefer to no have to go 4s, just to get it flying, and because the fan, and housing are not in any way damaged, I would love to reuse them. Any thoughts on the 50MM 10 bade models mentioned a page ago? If I have to get a whole new unit, I really would like it to fly well.....------Metalguy
My F-86 with the stock motor and 3s was pitiful as well. I didn't want to step that one up to 3s. The same combo in my MiG-15 works just great. A Don's Wicked 6000 kV in a wemo micro fan on 3s makes the F-86 fly like it should. It's a little better than my MiG-15 with the stock fan and motor on 3s. It appears the F-86 suffers from lots of drag and poor ducting.
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Old Jan 21, 2013, 11:40 AM
Wonderfully Wicked
The Don's Avatar
Willoughby, Ohio
Joined Jan 2002
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Joe,

The F86 has an outlet sized for a 60mm fan! So is way oversized for 50mm Don't know why they did that.
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Old Jan 21, 2013, 11:41 AM
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Sunnyvale
Joined Feb 2009
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Originally Posted by bunkx9 View Post
It's 14 degrees and snowing here. I'm jealous!
It is pretty cold in the morning and we only get a couple hours of the nice stuff... but still nice to feel some warmth...

Quote:
Originally Posted by alpea 41 View Post
Ontario Ca. Had to be close to 85 deg. F today was almost too warm
You so cal people always get the good weather! That is crazy!! In January no less....
Quote:
Originally Posted by Joe 1320 View Post
My F-86 with the stock motor and 3s was pitiful as well. I didn't want to step that one up to 3s. The same combo in my MiG-15 works just great. A Don's Wicked 6000 kV in a wemo micro fan on 3s makes the F-86 fly like it should. It's a little better than my MiG-15 with the stock fan and motor on 3s. It appears the F-86 suffers from lots of drag and poor ducting.
From what I have seen the F-86 has way too big of an exhaust to be any fun on 3s. And that goofy servo cover thing ain't helping either. However there is a guy at my field that added a makeshift thrust tube to it, balance the stock fan and added a 4s battery. That turned it into a really good flier! I used to do mock dogfights with him when I had my Mig-15 with the Himax combo on 4s. I had just a little bit more speed than him but just barely. It can be made to work if you spend just a little time on it...
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Old Jan 21, 2013, 12:05 PM
we can take off without that
green_flyer's Avatar
London, UK
Joined Nov 2008
740 Posts
Since I am messing around with power systems, I decided to put a 6-blade rotor back on the Lander 4600kv motor and test it with a Nanotech in the F35, to compare to the test I did recently.

The results are interesting. Clearly the 6-blade will produce more thrust at the same rpm (or same voltage) than the Lander rotor, but it will draw a lot more amps and watts to do that and will need a bigger battery to keep the volts up. I still prefer the Lander rotor for the lower amps, just need a higher kv motor to get the thrust I want.

F35, Phoenix 25, Nanotech 850mah 3s 45C, Lander 4600kv (43g 20mm inrunner), Haoye housing copy of JPower 50mm

Airframe__Motor/Rotor____Peak thrust___After 10sec___Amps(after 10s)__Watts(after10s)
F35______Lander+6blade__330g_______294g_________17 .90__________189
F35______Lander+Lander__317g_______294g_________14 .18__________155

F35, Lander Motor, 6 blade rotor (0 min 34 sec)


The older test of the Neutron 4900kv seems to show that even at the same voltage the 6-blade rotor has slightly lower thrust than the Lander rotor. My rough guess is that this 30g motor may be overloaded by the 6-blade rotor, the longer Lander motor may actually have more torque.

Airframe__Motor/Rotor_____Peak thrust___After 9sec___Amps(after 9s)___Watts(after 9s)
F35______Neutron+6blade____317g______279g_______16 .63___________165
F35______Neutron+Lander____333g______300g_______14 .08___________150

In conclusion its not as straight forward as I thought, 6-blade rotor is more agressive and can produce more thrust if large battery size is no issue, but Lander rotor is more efficient. Similar conclusion can probably be extended to JPower 5-blade rotor too since the blade design and pitch is same as 6-blade rotor.
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Old Jan 21, 2013, 12:26 PM
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United Kingdom, Warrington
Joined Nov 2012
553 Posts
In quite shocked to read people having problems with their f86's

I've never flown mine on 3s so I can't comment on how it flys on that setup, I upgraded as soon as it arrived as I know the stock setups are a little under powered. I love my sabre and flys awesome on 4s 1000 20c little less than half throttle with a few flat out passes I'm seeing 4.5 mins. I have some new 1000 30-40c that I haven't tried yet, and I'm looking forward to flying my 2nd sabre I just purchased which had already a 5800kv motor with an 8 blade fan which was running 3s 1300's, I'm gonna try this setup but have a feeling ill be running with 4s, gotta feeling its gonna be quicker than my last one just waiting for weather to buck up
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Old Jan 21, 2013, 12:28 PM
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United States, FL, Sebring
Joined Feb 2006
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A lower kV motor would allow the use of another cell. Efflux speed goes up, higher watts comes from higher volts rather than amps.
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Old Jan 21, 2013, 12:36 PM
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Mike20's Avatar
Joined Sep 2012
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Can someone post the link to the lander rotor on HK website? I feel dumb asking but I can't find it.
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Old Jan 21, 2013, 12:49 PM
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Vienna, Austria
Joined Apr 2007
1,880 Posts
post deleted, I misread the thrust figures and thought that the Haoye and the Lander have pretty much the same efficiency, but the Lander has the higher thrust while the Haoye has the higher amps...
still, the Hayoe 6-blader at 3 or 4s seems a pretty good and cheap upgrade to me for those who have the stock motor
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Last edited by mopetista; Jan 21, 2013 at 12:50 PM. Reason: copied the wrong measurement data at first
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Old Jan 21, 2013, 01:32 PM
chuck
santa barbara, CA
Joined May 2009
3,966 Posts
its to bad we dont have a easy way to measure efflux speed . all these thrust tests are good but w/o efflux numbers they only really matter on comparisons of the same rotor. differing pitches can determine whether they are best at thrust or efflux speed . as with regular props, u can reduce the pitch way down and increase the diam and produce way more static thrust at the same power, the down side being very low pitch speed . in a fan u can reduce the pitch , see more rpm, less amps, so it looks like it's more efficient but if the efflux is also down it may or may not do the job. and then of course u can differ the thrust tube size to compensate. lots of variables!

chuck.
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Old Jan 21, 2013, 01:59 PM
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Vienna, Austria
Joined Apr 2007
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...well, you know the discussions on the threads: as soon as you bring up this topic you get overly simplistic formulas thrown on the head which all assume that the speed of the exiting air is uniform - then, it is correct, you can infer the efflux speed solely from the thrust and the outlet area (and therefore, diameter).
This might hold in good approximation for longer thrust tubes where the air molecules had more opportunity to exchange energy with a resulting flattening of the velocity distribution.
However I have yet to read about when and where and why the approximation of uniform air efflux speed is working, and to what extent. People are just proclaiming that in a pretty dogmatic fashion which I find puzzling.
What has become clear is that the multiblade fans do accelerate air in a more uniform manner and therefore thrust is not suffering when running completely without thrust tubes - whereas for fans with lower blade count it seems better to mix the air more and possibly have some diameter reduction (air with uniform speed has higher thrust because higher velocity means a quadratic rise in energy needed whereas thrust rises just with momentum change, i.e., proportional to the efflux speed...)
Seems like it's still best to "fly" the differences between fans and combos...
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Old Jan 21, 2013, 02:45 PM
chuck
santa barbara, CA
Joined May 2009
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Quote:
Originally Posted by mopetista View Post
...well, you know the discussions on the threads: as soon as you bring up this topic you get overly simplistic formulas thrown on the head which all assume that the speed of the exiting air is uniform - then, it is correct, you can infer the efflux speed solely from the thrust and the outlet area (and therefore, diameter).
This might hold in good approximation for longer thrust tubes where the air molecules had more opportunity to exchange energy with a resulting flattening of the velocity distribution.
However I have yet to read about when and where and why the approximation of uniform air efflux speed is working, and to what extent. People are just proclaiming that in a pretty dogmatic fashion which I find puzzling.
What has become clear is that the multiblade fans do accelerate air in a more uniform manner and therefore thrust is not suffering when running completely without thrust tubes - whereas for fans with lower blade count it seems better to mix the air more and possibly have some diameter reduction (air with uniform speed has higher thrust because higher velocity means a quadratic rise in energy needed whereas thrust rises just with momentum change, i.e., proportional to the efflux speed...)
Seems like it's still best to "fly" the differences between fans and combos...
agreed! the in flight test takes into account all the variables and puts them to the real test.

chuck.
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Old Jan 21, 2013, 04:56 PM
Wonderfully Wicked
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Willoughby, Ohio
Joined Jan 2002
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Measuring efflux speed directly has been difficult for me in the past as the as the measurement varies depending where you place the probe and also there can be swirl in the flow as well so you have to take many reading and average. I found it much easier to calculate an average efflux value based on measured thrust and the outlet diameter. But once you have that value what do your really do with it? If you have a fixed outlet diameter then higher efflux = more thrust but you already know that as you measured thrust so you know the efflux will be automatically higher. The only time I used the efflux values was when I did a drag polar on a model to try and predict top speed. Having the efflux speed allowed me to predict how thrust drops off with forward speed and top speed was reached when thrust = model drag. These days I prefer to just fly and see what I get
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Old Jan 22, 2013, 05:50 AM
we can take off without that
green_flyer's Avatar
London, UK
Joined Nov 2008
740 Posts
Quote:
Originally Posted by Mike20 View Post
Can someone post the link to the lander rotor on HK website? I feel dumb asking but I can't find it.
Its this:
http://www.hobbyking.com/hobbyking/s..._EDF_Unit.html

unfortunately they dont sell the adapter.

Something like this could work instead, and I have a similar one fitted:
http://www.hobbyking.com/hobbyking/s...rew_Type_.html

but these only take shorter motor shafts. Some of my motors have 12mm shaft, so you would have to carefully deepen the 3mm hole in the adapter.
There is an advantage though, the M5 3mm prop adapter has a flange where you can drill out holes for the locating pins on the plastic Lander rotor, helps a lot when mounting on inrunners.
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Old Jan 22, 2013, 10:49 AM
we can take off without that
green_flyer's Avatar
London, UK
Joined Nov 2008
740 Posts
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Originally Posted by gooniac33 View Post
A good combo worth trying out. A fellow flier at my field had an AEO 50mm 8 blade fan hooked up to the stock Skyangel motor on 4s. Less than 19amps draw and just under 300 watts with a lot of thrust! It was in his Screamer and it was much more than 1:1 thrust to weight! I think that may be the best combo that I have seen thus far! Very efficient! It flew great too but even at half throttle it was pretty fast! My have to get some 50mm 8 blade fans to try out....

Flew my Katana more this weekend and am just loving the way it flies!! I still have to hook up the rudder but it is on rails!! It tracks like a much bigger ship and can slow way down as well! Great flying jet! I need to try out a screamer...
This is exactly what I wanted to try, but could not get the rotors on their own anywhere. That is a excellent low amp draw. I was going to try those rotors on 3s. Now I'm thinking of trying the new Lander 10 blade with the JPower motor, just need to mount it somehow.
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Old Jan 22, 2013, 11:55 AM
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Originally Posted by green_flyer View Post
This is exactly what I wanted to try, but could not get the rotors on their own anywhere. That is a excellent low amp draw. I was going to try those rotors on 3s. Now I'm thinking of trying the new Lander 10 blade with the JPower motor, just need to mount it somehow.
Will let you know how it turns out! I am using the slightly larger motor that comes in the AMX so it may have a slightly higher amp draw....
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