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Old Feb 26, 2012, 05:14 PM
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RiBell's Avatar
Canada, BC, Abbotsford
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OK I'll toss it out there.
I ordered the plans and short kit for a future build.
And as such I've been looking at fans for the first time.
I understan that a pair of 70mm fans are required and that Jim flew it with a pair of WeMoTec fans.
The E-Flite V-15 is also a 70mm fan that appears to be the least expensive of what I've found so far. I like it's price with the E-Flite motor. Is it worth it to pick up a pair of E-Flites or are the WeMoTec's a better choice.
Rick
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Old Feb 26, 2012, 06:24 PM
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League City, Texas
Joined Sep 2006
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The eflites should fly the plane just fine. I don't think Jim's power system was a particularly hot setup and the eflites should be up to the task. I will get the HET fans as they have not let me down and I've used them in several applications. The trick is finding a good motor that isn't going to break the bank. The eflites seem a little pricey to me so I will be going with something else. Probably the Cyclone Power outrunners that RC Castle sells. They are heavier than the eflites by about 40 grams each, but they are also $25 cheaper each and will make more power/thrust.
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Old Feb 26, 2012, 07:52 PM
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upland CA
Joined Dec 2004
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Keep in mind this is a twin so it will suck 2 times the amps...the eflite fans run about 750 to 850 watts each installed on a 4s pack. I use a 4s 4000 and can get 6 min of mixed flite on a single ...this same set up will fly the meteor even longer as you dont need 1600 watts on tap just to cruise around ..you should be able to reduce to an even lower power than a single for cruise...I am not sure but I think Jim was getting maybe 450 watts per fan maybe 500..Mine will get eflite fans...Only thing to check is the eflites are slightly larger dia...maybe 2mm

Not bashin the HET or Wemo as I have both and love them but the eflites are easy and available any where...
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Old Feb 28, 2012, 07:59 AM
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League City, Texas
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I think you will need more power than you think. This is not a small plane by any stretch. The fuselage is 61" long with a 51" wingspan. It's going to need 1600 watts just to get off the ground. Remember Jim's plane weighed 7 lbs. Watching the maiden flight video I would call the speed "scale". I'm not bagging on the e-Flite fans at all. I often discount them because they require a motor with a 4mm shaft, but the Cyclone Power motors come in both 3.17mm and 4mm shaft for all of their KV ranges. Jim's estimate was 900watts per fan on his. So for $25 less each than the e-Flite motors you can get a motor that will give you more power. You don't have to fly at full throttle, but it sure is nice to have on a go around.
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Old Feb 28, 2012, 09:25 AM
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upland CA
Joined Dec 2004
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I dont think a mega 16/15/3 in a mini fan will get any where near 900 watts on 4s.I think that was total power.( I think that was Jims power system).Hey Jim you watchin what was your power set up? and 1600 watt just to get off the ground? thast more than 200 watts per pound....it is a Meteor not a Sr71
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Old Feb 28, 2012, 09:58 AM
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Dang you are right. 900watts total. I wouldn't have believed it until I read it. That really opens up a bunch of motors then. I thought it was 900watts per motor.
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Old Feb 28, 2012, 10:12 AM
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Canada
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Hmmm. I have a set of plans here for a Scale Meteor mitt 70mm fans.
Free in one of the Brit Mags of late 90's? Same if not similar size to this model.
Kept the plans as they are V good ones indeed, despite the 'free' part.. big time.
But frankly Meteors never excited me enough to build one. Just couldn't discard the plans
Did I say they were V well done :-) ?

It used twin erm.. 'Ro-jet' fans and apparently flew well enough for Scale competitions.
Likely those were 150~175 watts each. With a Dozen sub C cells as ballast
Suppose it depends on the weight of your build and what flight perf expectations one has.
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Old Feb 28, 2012, 10:56 AM
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it is amazing what power level will fly ..in the old days...10 years or so ..900 watts was a killer set up...now we putt around on 1100 watts..and 850 watts is considered low level power..
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Old Feb 28, 2012, 11:25 AM
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League City, Texas
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Ok. I just ordered my power system. I went with super cheap.

Fan:
http://www.hobbyking.com/hobbyking/s...dProduct=22069

Motor:
http://www.hobbyking.com/hobbyking/s...dProduct=18542

This combo puts out about 1.3kg thrust on 4S at around 45amps and 650-700watts depending on battery size. The nice thing is this same motor/fan combo also works on 5S putting out around 2kg thrust at 65amps. I've got loads of 4S batteries so that's what I will start with and if it doesn't get it done then I'll buy some 5S. Also going to use some cheap electric retracts that I already have as well.

http://www.hobbypartz.com/77p-91-ere...-onepiece.html

I sized them and they should fit with no problem. Might have to make some new mounting plates as the Robart retracts that the model is built around are a little thinner.
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Old Feb 28, 2012, 12:22 PM
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upland CA
Joined Dec 2004
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Hi Steve, I have a set of those fans for testing..have not done it yet as the first run had a lot of vibration...but some of the numbers look pretty good for a low buck set up...I do like the multi blade set up as you can keep the rpm down..and still get good thrust..this may be a good combo for the meteor!..but I do like higher quality motors for ins.
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Old Feb 28, 2012, 09:11 PM
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Canada
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Quote:
Originally Posted by turbonut View Post
it is amazing what power level will fly ..in the old days...10 years or so ..900 watts was a killer set up...now we putt around on 1100 watts..and 850 watts is considered low level power..
Agreed..
But Air density /molecules haven't changed much at all :-)
What is the real difference?
Meatballs were barely operable 'OEM'. Scale implies a facsimile of the real thing.
Otherwise this would (should?) be in EDF forums
You wanna go vertical? A simple prop in slot will do that.
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Old Feb 29, 2012, 08:06 AM
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League City, Texas
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I've had pretty good luck with outrunners from HK. I have a $12 3200kv heli motor in a HET 6904 that has been in two different airframes (EDO F-15 and Phase 3 EF-16) and still runs like a champ. It pushes the EF-16 close to 100mph. I will do several bench runs with these before I install them.
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Old Mar 02, 2012, 09:12 AM
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Jim Young's Avatar
Brighton, MI USA
Joined Jun 2000
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Hi All,

Just for reference, I'm using Mega 16/15/3's in my minifan 480's on 4S x 5000mAhr. The original current draw was about 38A per motor or about 450W to 500W per motor. While mine is not a rocket, it does move pretty well and cruises well at 1/2 to 3/4 throttle and has all of the vertical that I want. On a paved runway, it has no problems getting airborne after a short roll. On grass, it needs to be cut short and needs some distance. With that in mind and depending on your typical flight surface, I'll leave it to you if you want more power or not.

I am currently using the stock hobby King bullet connectors on my batteries and ESCs. When I'm done with a flight, these connectors are pretty warm. They are next to the batteries, but the batteries are not as warm. Before I get the Meteor out this spring, I plan to replace the connectors with Deans to see if I'm loosing some power in the connectors. Also, the batteries (20C) are getting a bit soft and I will probably spring for a new set with a higher "C" rating. I also might go up to the next size nose wheel to see if it helps cut through the grass a little better.

If you are having problems finding the Minifan 480 pro, I would suggest the HET 70mm fan units and one of the HET motors to go with it. I think HET makes a 2 turn and a 3 turn motor for their fans. The 2 turn is good on 3 cells and the 3 turn is better on 4 cells. The main reason for these fan units is they are very close to the minifan 480s in size and mounting so I think they would require only minor modifications to the nacelles.

-Jim
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Old Mar 02, 2012, 02:53 PM
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SteveC68's Avatar
League City, Texas
Joined Sep 2006
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Jim,

Before you go through all of that trouble on desoldering/soldering battery connectors, you might want to read this short thread.

http://www.rcgroups.com/forums/showthread.php?t=1141543

Short story is you aren't going to see a difference between connectors.

For those too lazy to click the link.
Quote:
Originally Posted by mrforsyth
The results were somewhat surprising, to me at least.

Drumroll.....

The worst of the bunch was the faux Deans which came in at 6.2mV of drop at 10A. Calculated resistance is .62 mOhms.

In third place was the new Hobby City XT60 which had a resistance of .58 mOhms. This one really surprised me as I expected it to do much better.

In second place was the crimped APP which had a resistance of .41 mOhms.

Top honors went to the real Deans which charted a resistance of .35 mOhms.

While only a sample of one and not a scientific test by any means, the differences between the connectors in typical practical usage is negligible and the end user would not be able to note any difference in flight performance.

Example - At 50 amps, the difference in resistance (.27mOhms) between fake Deans (worst) and real Deans (best) would result in an additional power loss of about 1.4 watts. In a 1000 watt system, this is a .14% difference. Granted that the additional voltage drop would result in slightly lower current draw but the point remains and anyone who thinks that they can 'feel' this difference is cuckoo.

Lesson here is that unless you are drawing tremendous current (>100 amps) for an extended period of time that would result in undue heating due to voltage drop, pick the connector that you prefer but understand that there will be no noticeable difference in performance.

Let the rocks fly...

Mark
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Old Mar 02, 2012, 06:03 PM
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Jim Young's Avatar
Brighton, MI USA
Joined Jun 2000
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Mostly the Hobby King connector are a pain to connect and I need special adaptors for them
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