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Posted by dude_109 | Jun 09, 2011 @ 03:49 PM | 5,416 Views
Place holder for data on my 50mm EDF planes as it grows!!!

F-18 16.5A 293g acquired as ARF June 2010 from BananaHobbies
F-35 14.0A forgot acquired as ARF Sept 2010 from BH
T-45 15.1A 315g acquired as ARF Jan 2011 from BH
T-33 16.3A 335g acquired as ARF Jan 2011 from BH
F9F 15.5A 330g acquired as ARF June 2011 from ToySonics
MiG-15 16.7A 330g acquired as ARF June 2011 from TS

F-18 is my very first EDF. It gave me a BIG lesson on how to hand launch planes. My prop planes up to now practically flies out of your hands so its just a matter of not having too high of a throttle setting such that adverse torque will bank the plane before enough air speed is gained to stabilize that rolling tendency. As of June 2011, the plane has a little over 100 flights and is still going strong. Its small and light compared to the others and glides hands off for landing until the flare. Only negative is the nose cone keeps getting broken off if I touchdown with a combination of bad flight path angle in bad grass length. Other negative is lipo slot can't fit 4S easily w/o carving foam. Over all, a great relaxing plane to take to the field. Every time I think about retiring it and using electronics for the next plane, I fly "one last time" but have so much fun that I reconsider again.

F-35 is my second. It looks very cool looks in the air. Building it up was a major pain. It was very very difficult to route the ESC and servo wires into the tiny hole leading to the avionics bay. The elevators was the main complaint as the supplied hinges were sloppy. The full moving elevons looks scale and gives big surface area to be aerodynamically effective but snag grass easily on landing if you don't dump the elevator stick just at touchdown. After tearing it off so often, I decided to retire the plane.
Posted by dude_109 | Feb 16, 2011 @ 07:38 PM | 5,097 Views
Another EagleTree measurement to compare my new GenAce that I've been reading great reviews. My current fav is Rhino. Test bed is JPower 50mm EDF T-33 on stock motor+fan.

GenAce 3S 1000mah 25C ($10 shipped) 1 cycle - new

Rhino 3S 1050mah 30C ($10 not shipped) 50 cycles - 5 month old

Besides the cycle difference, I'd say GenAce wins by a mile. Just hate that the main wires come out 90* to the length of the lipo. This makes it hard to fit into smaller planes/helis.
Posted by dude_109 | Nov 30, 2010 @ 10:46 PM | 6,168 Views
Just recording amps draw data on my new plane so I can get rough idea of flight time as a function of throttle setting. Stock fan (5 blade), motor (4200kv), and ~2yr old Rhino 3S 20C 2150mah. Ran for roughly 5 seconds at different throttle settings as labeled in attached plot.

WOT = 30A = 3.4 minutes (probably more as voltage sags)
5/6 = 28A = 3.6 minutes
3/4 = 23.5A = 4.4 minutes
2/3 = 18.5A = 5.6 minutes
1/2 = 14A = 7.4 minutes
1/3 = 9A = 11.5 minutes

From the thread for this plane, cruising at 1/2 throttle is capable. I'll start flying with the fixed gears which will drag it more but once comfortable, I'll look to hand launch...less weight and drag. We'll see how long I can keep this in the air. Maiden in a few days
Posted by dude_109 | Nov 11, 2010 @ 09:21 PM | 10,546 Views
I recall reading/viewing someone doing a static balance of an EDF fan. Can't remember where it was so I took some pictures after just having gone thru balancing the fan for my new Airfield F-5E 64mm EDF.

In a nutshell, cut tape into strips. Put tape inside the "cone" from the back until it is balanced. That's it.

Of course the best way to balance is dynamic balance and usually involves the EDF fan and motor as a combination while spinning. Dynamic balance is much more complicated and special equipment is needed. Static is good enough for me and ... better than doing nothing.
Posted by dude_109 | Nov 09, 2010 @ 01:27 PM | 11,959 Views
I'm a hand launcher by birth. Can't stand scale planes with landing gears hanging down. Don't want to deal with complexity and weight of retracts. Too lazy to drag out a bungee set up every time I head out to fly. That leaves...hand launch. Prop planes are normally easy to hand launch assuming c.g. and trims are good.

EDFs, however, is another story. I would reference it to launching a highly underpowered prop plane. This thought causes high anxiety with RC pilots resulting in many people throwing like a Shortstop to First Baseman. I did such on my very first hand launch of my first EDF, a JPower 50mm F-18, after having over a year's highly successful experience hand launching various WW2 prop planes in my hangar. That launch resulted in 1 second of air time as the plane rolled massively to the left and crashed before I could even get my fingers on the aileron sticks.

Reviewing the traumatic experience in my mind over and over and over as well as looking at the mechanics of my throw in slow motion, I came to the conclusion that it was not "torque" roll, like a prop plane, as many have blamed it on but it was the position of the thumb and fingers. When throwing a ball (baseball or tennis, etc), my wrist would straighten out to be in line with the fore arm. This causes the thumb to be lower than the index finger at the time of release. Thus, my wrist action (right handed throw) was inadvertently inducing a left roll to the plane. I worked on...Continue Reading
Posted by dude_109 | Aug 14, 2010 @ 08:46 PM | 6,230 Views
I had 4 successful flights on the JPower 50mm F-18 using the E-Flite Pro 30A ESC which I didn't know but its default was medium timing, 15 degrees while the 5 point range was 5 to 25 degrees. My first indication this ESC was not happy with my motor was that it would shut down throttle anytime I push past 50% while the lipo was fresh. Once the 3S voltage goes below 12.0V, then it would function. However, fast throttle changes would still cause shutdown at times unless voltage was very low...like at end of flight.

Changing to lower timing helped to allow 100% throttle while voltage is still higher but this is no way to function. The bad thing with low timing is the thrust was noticeably lower. In my next 4 flights, 3 were very very very tricky on launch. 4th was crash that broke a wing to end my day.

E-Flite Pro 30A has to go. I went to my trusty Turnigy. Didn't have a 25 or 30A on hand so I used an 18A and also set it to medium timing based on the stock motor having 9 poles. This EagleTree static test is to see if this 18A ESC can handle the actual amps. As the data shows, it will be operating right at its limits. The voltage drop after the first few minutes will leave the amps draw at the rated limit. We'll see how much engineering buffer these ESCs are really designed for. I'll take a chance on a few flights until HobbyCity can restock their Turnigy 25A...
Posted by dude_109 | Jul 28, 2010 @ 09:09 PM | 5,842 Views
Got my 1st EDF...a small 50mm fan sized F-18 by JPower but imported by BananaHobby thru the name BlitzRC. Unlike the normal complaints about BH, plane was shipped same day as ordered and arrived to Texas in 5 calendar days. My 2 orders from BH has been fine.

I hooked up my EagleTree for a static data measurement while I'm grinding the fan to fit. Attached is the data for certain data points from 50% to 100% throttle. I'm guessing that EDF is similar to prop planes where the amps will go down 10-20% while in flight compared to ground test. In any case, the sticker on the fan stating 16.5A seems to be accurate compared to my 100% reading.

From this, I can speculate that flight times using 1050mah would be:

50% throttle = 8 minutes
66% = 5.5
75% = 4.5
83% = 3.7
100% = 2.9
Posted by dude_109 | Jun 05, 2010 @ 02:49 PM | 6,700 Views
Ground test data. This motor is rated at twice the amps of the 2205 and it shows with these data. Repeated test on GWS 8x4x3 after realizing that ESC was never programmed for full throttle range on DX7 stick.

* 2S lipo is Rhino 750mah 20c - 1.5 yrs old
* 3S lipo is G-Force 1300mah 20C - 2 yrs old
Posted by dude_109 | Jun 05, 2010 @ 02:39 PM | 6,632 Views
Turnigy 2205 (1088kv) with APC9x4.5E on 2S and 3S from in flight measurements using Alfa FW190.

* 2S lipo is Rhino 1220mah (2 x 610) 20C - 6 months old
* 3S lipo is G-Force 1300mah 20C - 2 years old