aflipz

My Feedback: (10)

yeah at 12oz before building i'll probably need a stronger motor. I would stick to my 1320's. if i keep the max load at 20 amps or less i should be fine and at least be saving a bit on the pack.


So you say there's quite a bit of coupling? (pitch out and roll on KE) About mixing, i'm a bit of a novice with that, if i put mixing with the rudder as master and aileron+ elevator as slaves, won't that mess up the rest of my flight characteristics? (example; in a hover, use of rudder to correct direction will also cause ailerons to roll and elevator to go up, won't it?) I have no swith to turn mixes on or off in flight (futaba 6xas)

I want a plane that flies like in afpd! It seems to me like all the models i download are absolutly exempt of all flight flaws little or no coupling at all in most cases. Is that because it's poorly simulated or is it that in the 10-15 or so planes i have flown none were designed right?

diceco

Hi all,

Thanks for all the great information on the Fliton Mini Edge 540 build. I'm just starting a build and your information is invaluable! I'd like to discuss some of the issues to get your input.

First and foremost is the landing gear issue. I hear there have been many failures but I've not found any details about the failures. What is the structural nature of the failures? I assume the carbon struts themselves are not failing and that the mounts are inadequate(?). If this is true, are the screws that hold the struts onto the cross brace pulling out? Is the structure of the fuselage failing. Where? Are the sides buckling? The cross member buckling? Anybody have a photo of a failure? Judging by what Tman has done with his bracing it looks like he's worried about the support structure of the gear and has chosen to beef up the cross brace.

The balancing issue. It seems to me that if one mounted the elevator and rudder servos in the rearmost area of the MAIN part of the fuselage there would be a significant improvement in the ability to balance the airplane, especially with the lovely modifications to the motor mount that Tman has done (something I'm planning to do as well!). We all know that any weight applied way back at the rear of the airframe will quickly move the balance point back as well. Even with micro servos (I'm using HS-55's all around) there will be a significant effect especially when considering that the darn servo extension wires weigh almost as much as the servo! Making a carbon push rod is a possibility but even using a very small solid wire/conduit set up (ex. Du-Bro 852) would be better than hanging two servos and their extension wires way back at the tail!

There seems to be a lot of discussion on how much power is necessary for adequate 3D. I'm going with a Hacker A20-20L. This seems to be about the hottest small frame outrunner out there. It only weighs 57 grams but puts out 190 watts according to the specs. Schulman is recommending it for the Quiet Storm which is a much larger airplane. I've got one in a 16 oz. Microbat using TP 1320 Pro-Lites and the vertical is simply ballistic. I figure the same setup in the Edge 540 ought to give excellent results. Any comments?

Thanks for your ear. diceco

TManiaci

My Feedback: (6)

It fails in both modes. A pancake landing will fold the crossmember, and a rough grass landing will fold the gear back. The whole member and attachement is very weak, requires good measures to prevent failure. The gear can break at the first bend too, but I have not taken measures to prevent failure there yet.

I think with HS-55's and the light front end, small motor with a TP1320, you will definitly have a tailheavy condition. Should consider pull-pull for rudder and get one servo up under the canopy area. Balance in the book range is perfect, so target that range with balancing efforts.

190 watts will fly this bird very nicely is you can keep it under 21 oz's. It won't be ballistic verticle, but it will fly like a bird with much more wing. Go for it, you will love it, no doubt.

diceco

I've worked out a bracing method to beef up the acknowledge weakness in the landing gear strut support.

First off, additional structure was made to fit across the existing cross brace thus forming a box that completely encloses the strut tangs of the landing gear legs. Then I made side plates for each side of the fuse that captures the tang box on it's outboard ends and runs forward to the main bulkhead and rearward to the wing spar tie brace. The plate projects upward to the bottom of the center brace of the fuse. Any loads from the landing gear will be transmitted to the main bulkhead, the spar tie brace, and the center cross brace. The extra thickness of the side brace precludes the use of the two outboard strut screws but with the tang being completely captured by the cross box the screws only hold the strut from falling out. I added another screw next to the existing one on the inboard side of the tang just for security and symmetry! I also had to square off the strut tang to fit snugly in the cross box. All the additional pieces were made from 1/8 th inch plywood. The completed modifications increased the fuselage weight by .6 oz. I reckon that this should hold the gear in place in anything but a crash landing in which case I'll have more damage than just the gear breaking loose! If I could easily reduce the landing gear stiffness I would, as IMHO it's too stiff. I think I saw a link once to someone that was making custom landing gear for these planes. Anyone remember that?

Next I'll tackle a motor mount modification ala Tman.

Cheers, diceco

[img][/img]

TManiaci

My Feedback: (6)

diceco,

Very nice mod's there bud. That will work awesome.

diceco

I made a trial fit of the wing panels to the fuselage and was astounded to discover that the wing spar was notched 1/3 of the way through from the upper edge right at the root rib. The rib keys into the the slot in the spar. Sure, the rib is glued to the spar but the glue joint won't be near as strong as continuous wood fiber. Good grief!! This may be great engineering for ease of construction but for strength it's a very bad idea IMHO! This is a point of very high bending stress of the spar from aerodynamic loads and this design reduces the beam cross sectional area to about 2/3s of it's original size. The spar is made only of balsa and fairly soft balsa at that. Perhaps they are depending on the glue joint of the wing root rib and sheeting to the fuse side although the fuse structure sure seems light in that area. I've recently read of an in-flight wing failure of a Fliton Jumping Jack, and if Fliton is using the same construction technique on the JJ as on the Edge Mini I can understand why it failed. These models are made to do some pretty violent maneuvers so it amazes me that such an elementary issue was overlooked. Perhaps the caveat is stated accurately in the manual when it says "Additional modifications may be needed (at your discretion) based on the builder's flying preferences." and "Always consult a professional for advice or assistance if necessary." It's too bad their construction doesn't inspire the confidence to fly the maneuvers that their namesake implies!

My first thought was to tear the wing apart and skin the spar with 1/64th ply but instead I "sistered" the spar across the void with a plywood brace. Not the best solution but one that may save the plane from wing failure. Photo 1 shows the wing spar bracing mod next to the stock one. Photo 2 shows the stock and cut away fuse parts to accommodate the extra brace.

diceco

[img][/img]

TManiaci

My Feedback: (6)

Nice mod diceco. I blindly ignored the wing spar issue. Not feeling that it was all that bad, I left it alone and worked real hard to get the wings planted in the sockets well and a over-done epoxy joint on the center splice.

I have pulled some real hard stick-slamming stunts. You'll find the bird flies VERY well with only moderate throws. Go to high rates, it is wicked crazy and violent when you go to the stops. So far, it's holding up real well. I've been watching the other threads on the Edge and the Extra (same joint)... doesn't seem to be a trend developing anywhere. It's mostly all about the landing gear problems.

Flyby-RCU

I just picked up my Edge today and I`m really impressed with the build quality. Also reading through this thread has given some really usefull tips.
I have an AXI 2808/20 with a 25 amp ESC and a 3s 2200 mAh pack but when it comes to prop sizes on electrics, I`m totaly lost.
Any suggestions here would be great!!

I`m really looking forward to getting this bird in the air

Cheers!!

Flyby

TManiaci

My Feedback: (6)

Flyby-RCU,

You SURE that is and AXI 2808/20? Not a 2808/24?

The 2808/20 has a pretty high Kv, and will require turning a really small prop. That motor is designed for speed demons, not 3D birds. I believe it will require around an APC 8x6E, pulling around 19 amps @ 210 watts at moderate loads, APC 9x6E will pull into the 240-250 watt range at around 23 amps. These are estimates... based onthe data on the Model Motors site.

Flyby-RCU

I`ll take a second look, but I`m pretty sure it`s a 20.
I got this motor for next to nothing from a friend that`s moving up to big electrics. I think it was used in a F27 Stryker.

Cheers!!

Flyby.

TManiaci

My Feedback: (6)

Makes sense, F27 Stryker is a very fast little screamer.

Well, if you must use a 2808/20, you will not be very pleased with 3D performance, but pattern flight will be fine (but very fast at WOT). You might consider buy/borrow/stealing a Wattmeter to set up better. You may find a larger diameter low-ptich prop that suits the setup better and gets the right loading.

Flyby-RCU

This kinda makes me want to get a new motor. My local shop carries Axi so I `ll stick wit that.
What motor/prop would you recomend??

Cheers!!

Flyby

TManiaci

My Feedback: (6)

The AXI 2808/24 will do an incredibe job with the APC 10x5E, pulling ~23 amps @ 245 Watts. You can kick it up to an 11x5.5E, and get into 290 watts @ around 27 amps as I recall, but that will require more ESC than you already have. I don't think you'll need to do that though... go with the 10x5E, you won't be dissapointed.

Flyby-RCU

Thank`s a lot, I`ll look into that.
I called a guy from work to see if he had a few props lying around and he said he had a 10x4,7 E prop.
I think I`ll give that a shot first and if the performance sucks, I`m off to do some shopping.
I notice there is a gold and a silver edition of the AXI motors, the silver ones being slightly cheaper. I take it
the silver edition has less performance??

Cheers!!

Flyby.

TManiaci

My Feedback: (6)

First, there is no 10x4.7 "E", thats a Slowfly (SF) prop. E-Series props are thick at the root, thin at teh tip. SF props are thin at the root, wide in the middle-to-tip. Uou shoud not push a SF prop much over 250 watts, can fail, not designed for that much power (thrust).

Second, the AXI 28XX series does not come in the Silver Series (yet), only the 22XX line.

Hope your hobby shop guy is competent... he seems to be leading you astray?

diceco

Say Tman,
Per your comment of the maiden flight; ["..... Had some range issues with her, messed with it for 30 minutes till we could get a good check. The culprit was likely the magnet latch for the hatch. Moved the anntenna and servo leads away from the magnets to get it to check. Still scary, it was doing all kinds of stupid stuff on the first check."] are you still convinced that you had a reception problem caused by the magnets? I'm trying to figure the best way to hold the hatch on. The magnet idea is such a good solution but if it causes reception problems I won't go there. Has anyone else had radio problems caused by the use of magnets to hold hatches or cowlings down? diceco

TManiaci

My Feedback: (6)

I can't be sure about the magnets as a cause, just that when I moved the wires, the problem went away. But I did put in a magnet pair that was WAY more than I needed. It' has been up flying several times now, no issues at all. I have flown it quite a distance away, not even a hint of range problems now. Put in a smaller magnet set, and route the wires away from it, you'll be fine I'm sure. Twist your tail servo leads together too, that helps, and it may have actually been the solution.

TManiaci

My Feedback: (6)

BTW... I have used magnets in a couple other planes, never had problems with range check in them.

diceco

Tman, thanks for the reply. Another question....What size magnets did you use and what smaller size would you think would do the job? I've never used these "atomic" magnets for anything before! diceco

TManiaci

My Feedback: (6)

The ones I used are VERY strong, and about 1/4" diameter x 1/4" thick. I saw some that were more like 1/8" thick, they would probably work fine.

djwalker

My Feedback: (1)

I definitely think routing the antenna near a strong magnet would cause reception problems. In fact, if the antenna is allowed to move around inside of the chassis, you could even induce small currents on the antenna. The field from those magnets should drop off quickly so keeping the antenna away from it will probably work (as you saw). Of course, I'm no RF antenna engineer so...

I saw the holes you cut into the bottom of your cowl T-Man. I would think that you'd want all of the cooling air to enter the plane and flow past both the ESC and battery (and exit out a hole in the covering in the rear of the plane ala mini Funtana). Just curious.

(BTW, I just ordered the Fliton mini Extra from Chief. It should ship tomorrow I think. Yehaw! If I end up liking the Extra as much as I think I will, I'll probably buy the Edge too.)

Cheers,

TManiaci

My Feedback: (6)

Dave,

I am running a small motor, AXI 2212/20, overloading considerably at 18 amps to get the most out of a light build. The heat is all in the motor, the ESC and Battery are not overloaded. I did open up a port in the rear too, bottom between formers in the rear. You can see part of the rear cutout in this photo.

djwalker

My Feedback: (1)

I wonder if these connectors are the same ones that come with all HiMaxx motors (since MPI distributes HiMaxx). So far, all of my electric motors have been HiMaxx so those are the only connectors I've used. I've never had an issue with them. The ones I am talking about have 'springs' on the male side of the connector though. They make a very positive connection and can be difficult to take apart.

BTW, I know it's the wrong thread, but I've started building the Fliton Extra 330 mini. I have to throw my kudos in for Fliton as well. It's a beautiful little plane. I suspect I'll end up getting the Edge too.

Flyby-RCU

The Edge is ready to go and I must repeat how impressed I am with the quality of this kit. I sure hope it flies as well as it looks. I`m going with the CG at the forwardmost point until I get familiar with it!
I got hold of a Phoenix 35 amp ESC but so far the 2808/20 motor is still mounted. Going to try with a APC 9X5E and take it from there.
Maiden flight will have to wait a bit as we`ve have the mother of all winters and it`s cold as Sh*t.

Being familiar with glow engines only, I`m having a hard time figuring out motors, kV, amps, props and such. Do you guys use some calc program or something to figure this out??

Cheers!

Flyby

TManiaci

My Feedback: (6)

Flyby-RCU,

There are tools to help "estimate" the results. We rely on multiple sources of information. The best one is reports of someone using the actual setup and accuratly reporting the results. This is hard to find.

In your case, you need to look at a couple things. First, the motor Kv from [link=http://www.modelmotors.cz/index.php?id=en&nc=produkty_vypis&kategorie=m_neod ym_ac&id_rady=axi_28&id_produktu=axi_2808_20&nazev _rady=Series%20AXI%2028%20GOLD%20LINE&hmotnost_rad y=(78%20-%20161%20g)]Model Motors[/link] says it is a 1490 Kv (rpms per volt) rating, 15 amp continuous and 22 amp burst for 60 seconds. This tell us about the speed the motor will turn at a given voltage.

You are using a 3-cell lipoly, and when properly loaded, it will generally pull down from a fresh charge (12.4-12.6 VDC) to around the "nominal" voltage of 11.1 VDC. So the no-load RPM should be "around" 11.1 V x 1490 rpm/V = 16500 rpm. That pretty high, and that's why I said earlier that motor is for speed flight, not 3D. You generally look for 3D rpm for Slow-Fly props in the 6000-8000 prm range, and the E-Series sport props around 9000-12000 rpm.

So, you must make a compromise here that will work, but downsizing to a relatively small prop to maintain a proper load on the system. This scale of plane ususally turns 10-11 inch diameter props, but this high Kv will require about a APC 9x6E or in that range to fully load it, yet avoid heavy overloading.

If you look at the chart on the Model Moters spec page (link above) you'll see an 8.5x6 prop pulls 21.5 amps at 232 watts, at 10.8 volts turning 11120 rpm loaded. That's about right, but AXI motors are way under-rated, so you can step up a bit from there (not too much). Without a wattmeter, this is the best estimate you have information for.

There other tools to help. You can estimate power [link=http://www.coloradogliders.com/propellerloads.htm]HERE[/link] using the last numbers above, it shows 239 Watts OUTPUT. At around 71% efficiency, you are pulling 336 watts at the battery. That's too high, as it represents around 30 amps. However, the calculators are not always accurate, so don't be too concerned about that.

You can estimate Thrust [link=http://www.lcrcc.net/thrust_calc.htm]HERE[/link] and it shows 36.8 oz's thrust with your numbers. That sound pretty close, and right where you would expect a motor of this class.

Another tool is [link=http://www.gobrushless.com/testing/thrust_calculator.php?prop=45&rb1=1&Value=11120&Al titude=1000&submit=Calculate+Now]HERE[/link], and it says you should turn an APC 9x4.5E and yeild 43.3 oz's thrust if you are acutally turning 11200 rpm.

As you can see, the tools are not precise. Testing is the best way to be sure of a setup. If you're going to be doing much in electric, the $50 is a good investment to insure the life of your equipment. Borrowing always works too [8D].