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Author Topic: Freewing EDF units (AKA Battery and Motor cookers)  (Read 1864 times)
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Konrad
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« on: April 27, 2017, 03:26:04 PM »

When I was last at the field I was appalled for what is now tolerated from an EDF power unit.

When I last was playing with EDF models, this was around 2000, we were using Sanyo round cells, Aveox brushless motors, and WeMoTec had just come on the scene.  Back then the key to EDF flight was trying to extract every last bit of efficiency from the power system. This was because of the very limited power available from the batteries. With the batteries of today (2017) 6000mAh lipos I was expecting to see some huge leaps in performance. Much to my dismay, most or all the sport EDF models I witnessed fly were landing after about 2 minutes of flight. This is much like the flight times I got at the turn of the century, with the NiMH cells.

As I investigated I found the the batteries were rather warm, actually hot. I asked if I could measure the amp draw on their power system. And just about passed out when I saw 100 plus amp draws for models that flew at what could best be called sedate to moderate. Speeds seemed to be in the 100 to 120 mph with verticals showing a distinct limit in height. As I looked deeper into the situation I was appalled to how the battery power is now wasted in today’s sport fliers EDF.  What I’ve been looking at are the many foam models from models for manufactures Like Dynam and Freewing. I was stunned as how little concern there is for the ducting and weight of the models. But what I want to discuss here are the limitation of the EDF unit themselves.

I need to state that what I think of efficiency in a EDF unit is how well it converts battery power to thrust. Or but another way the watts in verses the power (thrust) out.

Back at the turn of the century we suffered from units like the Robe Rojet, Morley fan & Aeronaut Turbofan. Firms like WeMoTec and Kress jets were trying to push the EDF from toys and half hearted conversions of glow ducted fans into powerful and efficient EDF units. I will be using the WeMoTec fans as my standard. It was the last EDF unit I had worked with and actually liked back in the old days.

The weakness of all EDF units is keeping the motor cooled while drawing large amounts of current. You might think that having the motor in the slip stream would make this an ideal place for keeping a motor cool. Unfortunately the air flow in the center of the duct is rather slow. And what little there is is actually flowing from the rear towards the front (to just aft of the impeller/rotor). This took a while to figure out. We can thank the carbon dust from the old brushed EDF motor which left very clear carbon tracks as to the air flow moving forward in the body of the motor.

The other concern is with noise. As we started to harness the electrical power to be able to spin the impeller past the 25,000 rpm limit of most glow powered units.  The once quiet electrical jet started to really develop shrilling whine. I need to state that the ability of the impeller to absorb power goes up by the cube of the rpm. Today performance jets are spinning the impeller at 50K to 60K rpm. This results in being able to extract 8 time the power from the same size rotor (usually not the same rotor).

In the first drawing I hope you can see how the cooling air flows from the aft high pressure air aft of the stators towards the front through the motor to the low pressure zone just aft of the rotor and adjacent to the motor body tube. This low pressure is a result of the high velocity air traveling over the gap between the rotor and motor tube. WeMoTec and others have also added heat sink to draw heat away from the winding into the fast moving slip stream. This does cost some thrust as a result of turbulence but the added cooling allows for the addition of more power to more than make up for this loss.  Properly sized and located heat sinks can also add stability between the rear of the motor and EDF housing.

In the same drawing I’m trying to show what WeMoTec has done to cut down on the siren whine. To cut down on the whine the stators need to be moved away from the trailing edge of the impeller blades. This drastically cuts down on thrust as it allow a vortex to develop between the stator vane and the trailing edge of the impeller blade. This vortex not only slow down the air to the stator inlet it also allows for a pressure rise right at the spot that the motor cooling air is trying to leave the motor. This slower higher pressure air is what quiets down the whine. To help keep the air going in the right direction more blades are added to the impeller. Please note it actually isn’t the number of blades that has quieted down the  EDF whine it is the distance between the trailing edge of the impeller blade and the leading edge of the stator vane. This distance extracts a huge penalty with regards to efficiency.  WeMoTec knew this and rather than just move the stator vaned aft the kept the EDF housing the same between the “Pro and “Evo” version of their EDF units. They took the opportunity to redesign not only the impeller but also the impeller blades. The result is that the quieter “Evo" is actually a few percentage points more efficient than the great old work horse the “Pro”. Not noticeably so, but every little bit helps. Please note that the “Evo” rotor draws about 30% more power for the same rpm as the “Pro” rotor. But produces about 30 plus% more thrust.

Back to the EDF units found in the foam entry level jets sold by Freewing and others. In an effort to keep the cost down (read cheap out the product) these manufactures are trying to use outrunners in EDF application. It became clear very early on that the outrunner EDF units found in these jets were just burning up when put directly into the EDF housings. The centrifugal fan effect of the spinning outrunner actually was fighting the natural cooling air flow through the EDF unit. The result was burned up motor as there was little or no cooling airflow inside the motor. Better EDF units tried the correct this with a spacer mount placing the whole motor in air that was close to the same pressure. This helped a lot, but gave us fits as the over hang ratio (mounting diameter verses length) cause the impeller to hit the fan shroud all to easily. As a result the impeller to housing tip clearance was opened up again causing  a huge loss in efficiency.  

Now in some of Freewing’s bigger EDF 80mm and 90mm units they have cleverly changed the outrunner units to rear motor mounting. This actually allows the outrunner’s fan to actually help draw cooling air through the motor. As an entry product this is fine as it actually gives the motor a fighting chance to stand up to the current demands of the 12 bladed rotor.  But it is very limiting as to allowing upgrades. The EDF units don’t allow for upgrading to different size out runners. Nor do they allow for changing to much more efficient impellers or inrunner motor. But as delivered they actually allow the outrunner motor to work, with a dramatic drop in motor failures  from over heating with the recommended batteries.

Having looked at the 80mm Freewing EDF unit I have found some gross design and errors. (MotionRC will not sell me a 90mm unit so we’ll have to wait for me to pick one up on the secondary market). One that Blows my mind is that the impelled hub is much smaller than the motor mounting tube. This results in an air dam that trips up the air flow causing all sorts of efficiency issue along with grossly impairing the ability for cooling air to flow through the inrunner motor. This air dam causes air pressure to rise just where you don’t want it, it you are concerned with cooling the inrunner motor. It also offers no benefit for the rear mounted outrunner motor. This small hub is a gross design flaw!

On the subject of flaws the impeller blades are poorly molded leaving huge flashing at the mold part lines. I’d like to thank MotionRC for posting such detailed photos of this issue on their web site. This is easy enough to clean up before balancing the rotor. Unfortunately the flashing issue extends down into the impeller hub. One need to totally disassemble the impeller to de-burr all this flashing. Otherwise the blades  are likely to shift as the impeller reaches speed (vibrate and explode)! The aluminum housing is of poor quality as there is a lot of mismatch of the molds cause huge part lines that disrupt air flow. You will have to spend a few hours cleaning up the housing. A nice benefit of the front motor mounting aluminum housing is that motor tube can be used as an effective heat sink.

So keeping with my philosophy of offering workarounds to flawed products, it is far too easy to say something is junk and walk away, here are some things you can do when dealing with the Freewing foam jets.
First, buy the ARF Plus versions. That is those without the EDF unit motor or ESC.  You won’t go wrong with the WeMoTec or the JetFan units for the EDF units for these model.  I highly recommend the inrunner motor. Remember to use a higher KV motor if you want to have the same battery cooking amp draw you experienced with the Freewing EDF power system. If you use the same KV rated motor you can expect a drop in current around 10 to 15 %.

For the 70mm jet use the WeMoTec Evo 9 bladed Impeller. I like the HET 2W-27 (2500Kv) motor on 6 cells.
For the 80mm jet I actually like the Freewing inrunner housing behind the JetFan 80mm rotor driven by the Neu 1410-2Y-SE motor on 6 cells it draws in the low to mid 90’s for amperage. If looking for much more power the 80mm JetFan unit is hard to beat driven by the appropriate inrunner (I like the Neu and HET inrunners).
For the 90mm jet I like the 90mm WeMoTec 11 bladed Evo. Again driven by a properly heat sinked Neu 1410-2Y-SE motor on 6 cells it draws in the mid 90’s for amperage. It will out perform the 100 plus amp draw Freewing set ups. If wanting more useful power the JetFan 90 EDF unit is great allowing for the larger 39/40mm motors.

While the WeMoTEc and JetFan EDF units cost two to three times that of the entry level Freewing units the extended life you get from the batteries or the huge bump in flight performance is well worth the added $100 USD.

http://www.effluxrc.com/EDF-units-EDF-components_c2.htm
http://www.effluxrc.com/MOTORS_c4.htm
http://neumotors.cartloom.com/shop/item/25324

All the best,
Konrad

Edit: To add links
Attached files Thumbnail(s):
Freewing EDF units (AKA Battery and Motor cookers)
Freewing EDF units (AKA Battery and Motor cookers)
Freewing EDF units (AKA Battery and Motor cookers)
Freewing EDF units (AKA Battery and Motor cookers)
Freewing EDF units (AKA Battery and Motor cookers)
Freewing EDF units (AKA Battery and Motor cookers)
« Last Edit: April 27, 2017, 03:53:21 PM by Konrad » Logged

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« Reply #1 on: April 28, 2017, 08:20:38 PM »

Seems to be somewhat of the same school of thought of St. Martin, on the Wemo/inrunners advantages in efficiency over the outrunner fans.  I'm not an expert on the larger fans, but with smaller fans I'll take any benefit in weight reduction/efficiency over heavier outrunner setups.  From a realist's standpoint, I'm convinced that these heavier, high powered ARFs don't fare well, other than in the hands of well experienced pilots with adequate fields/runways. An ounce shaved here and there can make a big difference.  A bit different territory with 40mm and under EDFS, but as of lately I've been enjoying EDFs that fly with 30% T:W and less, as well as 100W/b with a 12mm inrunner and an AUW of 8oz.  The same scenario exists however, as these models have inrunner fans versus outrunner fans.  The added weight/power consumption is pretty much self defeating, if a person can build reasonably light. 
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Konrad
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« Reply #2 on: April 29, 2017, 01:52:20 PM »

Who is St. Martin? Sounds like a fine Caribbean rum!

Truth be told these “new”* foam ARF jets actually do fly. They often have way too thick a wing, as a way to gain some stiffness. This thick wing makes them slow. But aids with the higher wing loading (EPO foam is not light) making flying and landing very easy, even sport/trainer like.

I know of no foam jet that has retracts than can land on anything other than well prepared runways. Again due to their weight they aren’t Park Fliers, and should only be flow at model air fields.

My observation is that in the last 20 years EDF jets have actually gone backwards as far as performance goes. Maybe that’s ok as the average flier can now fly them, no need to have racing or pattern experience.
What I’m appalled with is the apparent lack of advances in the propulsion system. With the sensorless brushless motor and the huge advances in the batteries I expected to see phenomenal performance improvements, even at the sport level. Instead I find EDF units that are actually less efficient and just waste what advancements have been made with motors and batteries.

*My avatar is my old (1990’s) Robbe BAE 146 using four Rojet fan units, driven by long canned 410 brushed motors, running two 10 cell 2000 mAh batteries

All the best,
Konrad
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« Reply #3 on: May 02, 2017, 02:34:28 AM »

Steve's an experienced old time builder, who has been building and flying EDFs since the .049 powered Berkeley days.  I'm sure you would remember him, from the forum over there.  I think EDFs have really gone backwards, in the sense that the earlier good ARF Alfas would hand launch, perform well, and land easily, with a 370 inrunner in a 55mm fan.  The only reason the battery may have needed to be larger than a 3s-1200, was maybe for balance reasons on some subjects.  Then they started throwing more weight and power at smaller EDFs, as well as retracts.  As far as kit and scratch builds are concerned, I see few concentrating on light weight builds, and not many building anymore either.

Well over 10 years ago Dave Ramsey showed that good sized, good looking stick and Microlite covered Lear jets and airliners could fly well, with brushed GWS EDF50 fans and NiCd cells.  Soon after lipos and 12mm inrunners came out, which really made those types of builds practical.  Since then, I can pretty much count the number of builds that followed his lead on my 2 hands, with a good number of them probably being mine.  Most everyone now uses an outrunner powered small fan, or a fan with a 20mm inrunner versus a 12mm inrunner on smaller EDFs, where they require a battery twice the size of what I would use.

Recently a guy posted on that other place looking for airliner plan, for a stick and tissue type EDF build.  Seems few will even consider building with a 3-view.  Of course there are good quality free 747 3-views on the internet.  I started a stick and tissue type Lear 23 build recently, and the available 3-views and sections aren't very good.  Still, how difficult is it to layout a few formers/keels/stringers and build a model?  I'm actually notching formers right now, as I can do that upstairs at the pc. The model will use the 30mm GP fans, for nacelles as scale as possible for 26" span.  In more recent years, there are numerous small BL fans available, and again, I can pretty much remember OTOH all of the scale like balsa builds I've come across on the forums, using these fans. Had this gear been available 15 years ago, the builds would have literally been coming out of the woodwork.
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Konrad
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« Reply #4 on: May 02, 2017, 11:42:05 AM »

St, Martin an RCGoof’s user name, I recall his work. I think you have shamed me into building my West Wing kits of the Hunter and Alfa.

Gold plating the trash heap. Or put another way, when life gives you lemons make lemon aid. This is a character flaw of mine, trying to extract the best from what life gives me. I don’t suffer mediocrity gladly.

This housing came from a production run of 80mm inrunner housing that Freewing had shipped with outrunner rotors (6mm hubs). We all make mistakes, but this one allowed me to get these EDF units for about $20.
I like that the housing are aluminum and fit the Neu 36.5mm diameter 1410-2Y SE motor perfectly. But the casting work is very poor. I had remove a lot of flash at the part lined and blend down a lot of raised material in the gas path (airflow areas). Since there is less than 0.25mm clearance between the motor motor mounting tube this allows the housing to be a great heat sink if one supplies some thermal compound to take up this small clearance. So far I have not needed to use additional heat sinks using a six cell 6000 mAh battery and the JetFan rotor. 
Along with being a heatsink the housing fits the Freewing 80mm aircraft (I’d hope so, but you never know with todays toy manufactures). I’m using this set up in my Freewing Mirage 2000. It actually is out performing the High performance Freewing 1750 KV inrunner upgrade they sold for these models. Not only are we getting more thrust at speed but also we are getting more run time* for any given battery capacity.

In my case this upgrade costs me $20 for the Freewing housing, $50 for the Neu motor and $64 for the Jetfan 80mm rotor for a grand total of $134. This winds up being a $40 premium but the performance with the Jetfan rotor is so much better than what we get with the 12 bladed rotor Freewing sells with their High Performance upgrade.


* The Freewing 80mm 1750 KV inrunner upgrade  and the combo Jetfan rotor and Neu 1850 KV 1410-2YSE  both draw in the mid 90’s amps. The beauty of the Jet fan is that it does this with about 5mm more pitch to the blades and with a higher rotor RPM. At full throttle the run times are close to the same, with the Jetfan rotor flying the plane noticeably faster. Where the extended run time come from is that with the Jet fan you can pull back on the power and still have a respectable flight as far as aerobatics and such.

Pulling back on the throttles on ether the Freewing or Jetfan EDF units really lowers the amp draw. Now partial throttle puts a larger load on the ESC (This has to do with switching losses and is a subject for another post). As a result I’m becoming real partial to ESC with free wheeling circuits. These free wheeling circuits (Active Rectification) are using the idled MOSFETs of the unused leg to protect the powered MOSFET. These MOSFETs have a much lower forward bias resistance than the normal protection diodes found on the MOSFET package. This lowers the heat in the ESC at partial throttle.
https://en.wikipedia.org/wiki/Active_rectification

All the best,
Konrad

P.S.
I see that Freewing is upping the battery load as the new inrunner package is using an 1820KV motor. This opens up the possibility of just pulling of the Freewing adaptor from the HET motor and attaching the Jetfan rotor directly to the motor. I haven’t done this, I assume the HET motor shaft is 5mm.
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Re: Freewing EDF units (AKA Battery and Motor cookers)
Re: Freewing EDF units (AKA Battery and Motor cookers)
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« Reply #5 on: May 04, 2017, 12:06:50 AM »

West Wings Hunter.  Now that's a subject I've always wanted to build.  I've seen a few nice conversions of the kit.  Speaking of Neu motors, one of these days I'll place an order for their 12mm inrunners.  I wish they would stock them, but it hasn't been the case.
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« Reply #6 on: May 04, 2017, 11:44:50 AM »

Konrad,

   Interesting thoughts.  My field is rough (at least as rough as Rancho).  Guys who fly edfs always complain about it but never help with field maintence.  Though i suspect if they took your advice to their models the models would fly better and they could take off easier (providing they still have the airmanship to fly the thing).  One guy had a good landing but a main retract came off and he blamed the runway on examination the retract unit was glued in (at the factory) with four dots of Hot melt. 

   Feels more and more that the BNF craze is making toys not models...

Hank
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« Reply #7 on: May 05, 2017, 04:45:48 AM »

They're sure not building much any more, with the BNF craze.  If you do post something interesting that they can't buy, like the little 30mm EDF ME262 I have, all you hear are comments about how Horizon needs to come out with one for them.  Got a few evenings in, with a full fuse and nacelle kit for a 26" Lear Jet with 30mm EDFs. Few people sketch in details on a 3-view and build from them any more.  Years ago, it's how most plans were drawn up. As for landings, I'm looking for something like this.  Watch the landing on Dave Ramsey's ultra light Lear Jet.  No landing gear problems here: https://www.youtube.com/watch?v=ERcxn66orts


Speaking of hot glued in LG mounts, one of the last ARFs I bought, the Eflite Sea Fury, had the mechanical retract units hot glued in, and really hot glued in.  Apparently the glue set and one unit wasn't quite properly positioned, causing flex in the plastic base.  Not wanting to rip everything out, I had to scrape plastic away, until the unit operated smoothly.  Seems par for the course with ARFs.
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Re: Freewing EDF units (AKA Battery and Motor cookers)
Re: Freewing EDF units (AKA Battery and Motor cookers)
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« Reply #8 on: May 09, 2017, 06:12:11 PM »

Bill,

  The lear jet looks good.  I should build a model from 3 views someday.  I know i can i just have so many kits i normally start with one of them. 

Hank
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« Reply #9 on: May 09, 2017, 11:01:51 PM »

Thanks
I actually quit buying kits after a few started collecting dust, and I'm constantly finding subjects that I would rather build, which require scratch building. Over time I've found myself pursuing the oddball subjects that we can't find kits for.  Either that, or more recently building some of the worst kits one could start with, Grin such as the Comet Super Stars and then redesigning the wings, just for the novelty of having the only r/c conversions out there.
 
The 3-view builds are incredibly easy after building a few, especially with really good 3-view drawings with cross-sections. With some of the plans for the old days, I've found the actual source 3-views that they used for their plan's starting point.  There are cues which make it obvious sometimes.  With CAD, it's changed things to where many people these days won't build from anything, unless it's a CAD based plan.  

The important thing is to use a fine tip drafting pencil to sketch a precise outline on the 3-view.  For the top view, sketching the profile on only one side is necessary, since the overall former dimension is mirrored across the centerline. With the fine tip pencil sketched lines, accurate former dimensions can be taken.  They're more difficult when the profiles deviate far from a pure round, like the Sncaso So.6000 below.  That one required a bit of padding on a few formers, to get the shape correct.  The Lear jet is pretty close to a perfect round. As long as you have printed sections that you can use for reference, it's pretty easy to interpolate a bit, and draw your formers using them as a reference, as they will ideally be only a few mm larger or smaller than the actual former dimensions measured from the profile views.  I draw one side, fold the piece of paper on the centerline, and then trace the other side of the former, including the notch locations.

The full perimeter "mid air" construction works well.  I actually prefer it to half shell, as I continually adjust the keels for straightness, as I work my way down the fuselage, before gluing them in place.  With a half shell, I end up doing essentially the same thing anyway, as adding keels and/or stringers to a single fuse side while still on the board, has it's issues. They almost never come off straight, and need to be straightened when adding the keels/stringers to the other side.   This subject has front and rear side keels.  The keels are glued a the third former from the nose (including nose former) first, and then I work in both directions, adjusting the keels in the formers, for a straight fuselage.  The nacelles worked out well also, only adding 2-1/4 grams of balsa weight to each one.
Attached files Thumbnail(s):
Re: Freewing EDF units (AKA Battery and Motor cookers)
Re: Freewing EDF units (AKA Battery and Motor cookers)
Re: Freewing EDF units (AKA Battery and Motor cookers)
« Last Edit: May 09, 2017, 11:12:16 PM by Bill G » Logged
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« Reply #10 on: May 14, 2017, 02:00:43 AM »

Just finished flying a couple of Freewing F-5 back to back for the last week or so with Revo 4400mAh 435 series 620 gram batteries at 6K feet altitude. The only known difference between both Freewing F-5’s was the EDF power system.** Mine the one I’m holding in the photos has the gold plated EDF unit and uses a YEP 100 amp ESC. The other F-5 is stock with the upgraded Freewing 1750 inrunner, using the Freewing 12 bladed rotor and controlled with a Hobby Wing 100 amp Pentium ESC.

On the ground and after a 10 second power run, the stock  upgraded Freewing 1750KV inrunner 80mm EDF was drawing 92 amps*
The Gold Plated Trash Heap (Neu motor 1410/2YSE 1850KV, JetFan Rotor in a Freewing inrunner housing) was drawing 86 amps*

I have to admit I was a bit shocked to find that the battery load was so much lower for the Gold Plated Trash Heap.

Flying the models at the same time or in rapid secession showed that there was no difference in speed or in the vertical performance between both F-5s. The plane with better speed or vertical could be traced to the pilot that was better at holding the initial energy. The lower energy draw of the Gold Plated Trash Heap EDF (130 watts lower) was noticed in the energy that was left in the batteries at landing.

While they sounded a bit different, both F-5s had the pleasant swoosh sound so many folks are looking for in todays EDFs

*Note that the Revo 435 series batteries are using cells that can be peaked charged to 4.35V. These tests and flights had the cells charged to 4.30V. Both ESCs are using the low timing setting for inrunners.
**This is in error as my F-5 with the Gold Plated Trash Heap had the bifurcated exhaust outlet opened up to 87% of the SFA. We calculated the outlet of the stock F-5  at 78% of the SFA (44.5mm diameters). May drop a Gold Plated Trash Heap into a stock F-5 airframe and see quantitatively how the outlets perform.

All the best,
Konrad

P.S.
Flew my F-5 one time on the stock outrunner 80mm EDF system and with 5000 mAh Zippy batteries. This was a real challenge up here a 6K feet altitude as one needs to fly very smoothly trying to maintain flying speed. No wonder I was given my F-5, thanks I think, as in stock form it isn’t fun to fly!
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Re: Freewing EDF units (AKA Battery and Motor cookers)
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« Reply #11 on: May 15, 2017, 12:39:33 PM »

Trippy Shirt Bro.
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« Reply #12 on: May 15, 2017, 01:11:36 PM »

Konrad,

   The F-5 looks cool.  As my dad says you have to pay for efficiency so your gold plated trash heap is working ok.  Your description of how the model flew on the stock out runner sound correct though, most of those jets seem to fall out of the sky due to lack of pilot skill. 

 Maybe you need to build a balsa "FF style" jet for one of these 80 mm EDFS.  Turn all these Motion RC ships in to proper beer coolers.

Hank
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« Reply #13 on: May 15, 2017, 05:16:25 PM »

P.S.
Flew my F-5 one time on the stock outrunner 80mm EDF system and with 5000 mAh Zippy batteries. This was a real challenge up here a 6K feet altitude as one needs to fly very smoothly trying to maintain flying speed. No wonder I was given my F-5, thanks I think, as in stock form it isn’t fun to fly!
Beautiful jet, but probably not for the masses.  I'd imagine there's at least a few of these in basement storage crashed pile form, where the owners aren't posting about it either.  Not much different from an F104, with the wing configuration. 
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« Reply #14 on: May 16, 2017, 12:53:35 AM »

Trippy Shirt Bro.
I didn't realize I had that shirt on until I saw the photo. "In a World without Fences Who needs Gates -Java" this was a freebie from some Sun Microsystems Java developers conference in the late 90's. The last time I wore this T was in Renton Washington and just about got lynched. Shocked
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« Reply #15 on: May 16, 2017, 01:07:45 AM »

P.S.
Flew my F-5 one time on the stock outrunner 80mm EDF system and with 5000 mAh Zippy batteries. This was a real challenge up here a 6K feet altitude as one needs to fly very smoothly trying to maintain flying speed. No wonder I was given my F-5, thanks I think, as in stock form it isn’t fun to fly!
Beautiful jet, but probably not for the masses.  I'd imagine there's at least a few of these in basement storage crashed pile form, where the owners aren't posting about it either.  Not much different from an F104, with the wing configuration.  
Don't intend to turn this into a Freeewing F-5 thread (I'll do one later) but the F-5 flies fine at sea level even with the stock outrunner motor. The issue is in landing if you get too slow and the nose too high she will do a fantastic rendition of the "Saber Dance" (look up Saber Dance F-100 on U-tube). I agree she is not for the masses, but one doesn't need to have superman type skills ether.

https://www.youtube.com/watch?v=Q2qqKwndFW0
BTW; I call my F-5 "The Dancer"  Roll Eyes

I'm surprised at how any posts that are critical of products get suppressed at most forum sites. So I'm not surprise that guys aren't willing to discuss their issues with this jet or any other product. It just isn't worth the effort in the B2B internet of today. I try to use these forums as a counter to all the money and hype the sales and marketing guys are spending trying to one to buy their junk. I'm a hold out to the days of the information highway.  

The Freewing 90mm F-104 actually flies as good or even a bit better than this F-5. Now the smaller 70mm Freewing F-104 has a plethora of issues!
« Last Edit: May 16, 2017, 01:19:17 AM by Konrad » Logged

Cut it twice and it's still too short!
Hank G B Z
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« Reply #16 on: May 16, 2017, 07:18:59 PM »

Ok so it's a computer thing.  That makes sense.  I thought it might have been a dig at the current administration but i've never known you to be overtly political...

Hank
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Konrad
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« Reply #17 on: May 16, 2017, 09:30:21 PM »

Ok, I can see that interpretation as a comment on the southern wall!
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Cut it twice and it's still too short!
kep
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« Reply #18 on: June 12, 2017, 01:05:20 AM »

Well my learning curve just got steeper.  I still plan to post all the rib and parts sheets and I will "do over" build per plan sheet just for my personal reward after 60 years.  It will hang half open so I can see the built up fan.  My updated version will take more research.  This forum displays issues I thought were now tried true.  I welcome any  comments and thoughts. As I said, I'm an old fuel and balsa duffer.  I'm confident about structural enhancements but outrunners, inrunners, watts and each might be too long of a kit bash for a converted chainsaw engine guy on my little Berkeley F11f1. Besides, hot lithium polymer and frying electric motors sounds like cadium and methanol might still be my home field.
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