OK, if I keep modifying these ARF's like this the folks at Brodak's are going to get CHEEZED!  However, its like cooking; you get a little of this and some of that, you wonder how it might go together and... GOULASH!

This story starts back at this year's fly-in.  I got a chance to fly John Paris' (actually Frank Carlise's) Super Clown with the Brodak electric system in it.  The experience was eye-opening and a power system followed us back home.  Discussions with Mike Palko indicated he was pessimistic about using the power system outside of its intended use, however, we were convinced that the power available would handle a larger, draggier bird and set-out to find a test bed.  Upon further review, we came back to an Oriental.  Dad had one nearly RTF, seemed
like the fastest way from there to here was to "borrow" that bird, gut it and stuff the electric power package in it.

So that's what I did.  Also blunted the leading edge, shortened the flaps, and sealed the hinge lines - like the OTHER Oriental I am flying - see that post for details.

Anyhow, the key to this mod was adding a nose ring off the end of the existing engine mounts.  To this some lite ply side panels were added then aggressively shaped so the cowl would fit over them.  Finally, the fiberglass cowl is glued on with silicone seal, tying everything together and reinforcing it all.  Purpose built this could have been
lighter and stronger.  Because the cowl is glued on, the existing cut-out in the cowl (for the slimer engine) was made symmetrical and the engine installs from underneath and slips forward to the firewall.

The Brodak battery ALMOST fits perfectly in the tank compartment.  If the wires came off the front instead of the side corner (or if the fuse was a tad wider), the battery would fit on the mounts where the tank normally sits.  However, the web between the mounts, then the mounts themselves were removed and the battery easily fits to the top of the fuselage.  Lots of room for airflow too.  A hole was cut in the rear bulkhead to channel air out under the wing, and two holes cut in the top to vent heat there.

The engine controller, timer and arming switch were a bit more perplexing.  Besides this is a test bed and it is better to make FUNCTIONAL installations rather than pretty ones.  That's my story and I'm sticking to it.  Desire was to get the controller where it would cool.  The timer and arming switch pretty much have to be exposed to
power up the system.  Anyhow, the ESC was siliconed into a hole cut in the tank, uh, I mean battery hatch, the timer up on the fuselage side where it can be seen and activated, and the arming switch on the side.

Several folks have posted that their best luck came with the 9x4.5E APC prop - so that's where we started.  Sounds small, but historically there is precedent.  Folks like Kostecky & Gierke used to use 9-6 three blades
on larger/heavier birds than the Oriental.  I rationalized that their 3 bladers running around 8k-9k "filled the disc" about the same as the 9" 2-blade at the expected 12k output.  My flight with the Super Clown also demonstrated that the little flatter pitched prop had a LOT of recovery in it if the bird got stalled.

Going in I was more afraid of TOO MUCH speed rather than too little. The Brodak system is purpose built and not tunable - so any tuning would have to be with props, aerodynamics, and line length.  The SLimer Oriental flies on 63' lines so thats were we started.

Test flight showed lap times around 5.0 sec ON 63' LINES, with LOTS of power to do anything!  Near end of run it slowed down quite a bit, and shut off on cue at 5 minutes.  Opened up the fuselage and discovered the battery had ballooned!  Second flight started off around 4.8 sec lap times and got (I think) a low voltage shutdown short of 5 minutes.

In an effort to slow down the bird and maybe lighten the battery load, my brother Arch the "propellor artist" tricked out the 9x4.5 by narrowing the blades substantially.  Got us a couple tenths of a second lap time, so we went extreme.  Flight 4 was with a stock 9x4 PowerPoint wood prop.  Starting lap time was 5.3 sec - about the same as the LA40 Oriental!  Then a bout 1.5 minutes into the flight the motor gave a shut down signal.  Then did it again at roughly 1 minute intervals until it finally shut down at 5 minutes.  Discussion with John Paris indicated he had a similar experience and determined the ESC was bad, so we got a replacement.  BRODAK STANDS BEHIND THEIR PRODUCTS!

Figured we had it nailed, but subsequent flights showed the thrust was just too far off to accept, so went back to the modified APC. 

My plate is full and my experience lacking, so the bird was packed up and sent home with my nephew Archie, the RC Electric pylon racer.  A couple days later he calls and says all the smoke got loose from the charger!  So he used his Hobbico charger.  Took it out to fly, set the timer for 6 minutes and did a full pattern.  Reports more than enough power & duration.  Second flight like the first except he added a few extra laps here and there.  He has a Triton on order and a box of alternative new props to try.  The Triton will really let him see ho hard he is working the battery.   Figure if we can get it flying on a 4 pitch with diameter to suit we'll pretty well have it licked.  As it is, Archie reports (and I concurr) that he would not be afraid to take it to a contest.

Summing up, we are able to EFFECTIVELY fly the 47 oz bird with the stock Brodak system using a modified APC prop.  If we can do some more prop tweaking I think the system will be pretty much good to go!

Hi Dennis & Archie,
   I am VERY surprised you have gotten this far with the Brodak power system!! I almost need to see it to believe it .  It is by far the lowest watts/lb that I have heard of flying the pattern. I look forward to hearing more in the future of how things come together (or apart  ). I would love to compare it to other electric ships I have flown/seen. Does it slow up hill? What are the temps after the flight? What kind of wind have you flown in?

   A thought on your lipo batteries. Before your first use "break-in" your packs by charging and discharging them ~5 times at 3-5C (12-20amps). I wrote about this in the last issue of CLW. And also when you charge use a balancer, if you are not doing so already. (I apologize if this is over simplified! I know Archie flies electric already)   

   The Brodak power system is limited to the following:

Motor- 400watts max, 14volts max

ESC- 45amps, 4S lipo or 12 round cells (I am fairly certain the max voltage is correct)

Battery- 40amps constant, 48amps burst (10-12C discharge)

   Congrats  , Mike

Archie,
   Great info so far. Congrats on making the USA team back in 2000! That is always something to be proud of no matter what aspect of the hobby it is.

   It is true NiMH cells perform drastically different when they are hot and cold. When I flew NiMH cells in precision aerobatics it was hard to time the charge cycle to the flight order. To get the most from the cells I needed to pull them off the charger (HOT) and fly them within 5min.

   There is no gain or loss when charging lipos. The majority of lipos are still charged at 1C (some of the high discharge 25C + can be charged at 2C or more "supposedly"). And lipos do have a much flatter discharge curve (to our advantage).

   The best charger I know of is the Astro Flight 109. It is affordable, VERY user friendly and works great. The Thunder Power 1010C is also an excellent charger, it is costs more, is more complex, but it to works very well. There are others (Triton, Schulze), but I feel the first two are the most popular.

Mike

PS: Check the current levels in todays F5B and F5D events. CC doesn't make a 300amp ESC for nothing!!! 

     

   

I couldn't get the JMP-2 timer to work with the Brodak ESC--my guess is that it wasn't being armed right. But without documentation I am not sure. Since the Brodak timer is an entry level timer (with one throttle setting---max), I went ahead anf bought a Castle Creations 35Amp Phoenix ESC. There sound like there may be better ones for CL out there now---I am not sure, but I think the next step from the E-Super Clown requires at minimum a ESC and timer change. I have been running the Brodak Motor on the Castle Creations ESC and JMP2 timer.

The problem with the BEC's and >3 Lipos in series is that when you load down the BEC with lots of servos, which can draw a lot of current, is that the BEC has to drop the battery voltage, >15V, down to ~4.8V or so. Since most of the BECs are linear, that means they have to dissipate the watts (=(BattVolt-4.8V)* Amps)internally--usually in the regulator. However for our timers, the draw is really small, so I doubt there is a problem in overheating the BEC. However the ESC may still turn off the BEC if that's the way it is setup. Since I am trying to standardize on 3s Lipo's (cheap-cheap!) I haven't had that problem.

It is true that the ESC works somewhat harder at partial throttle than at full, and that the battery current draw you measure on a watt-meter is only the average current over both the on and off cycles. However the Castle Creations say it is "ok" and the circuits are able to handle the higher instantaneous current during the "on" stage of the cycle (within the limit of current ratings and cell counts). I've been running my SuperClown setup at ~30-40% throttle settings with 10-6 and 10-6 props and haven't seen any problems with average current values in the 20A range (35 Amp rated CC Phoenix ESC and a 3s lipo). But maybe I am not stressing things enough!

We will see with my electrified Nobler. Coming soon.

Hello Dennis and Archie!
Glad to see you playing with E-Stunt. let me list a few points that could take days to fully discuss.
1) You do want to run an RPM governor.
2) You want a governor with the fastest response time and highest gain practical without causing wild RPM oscillations
3) You will eventually need a prop brake that works in governor mode, but for the ESCs that don't have it, this is just upgradable software.
4) Though Igor correctly points out the thermal load downsides, you want to run the governor with lots of headroom in order to improve the airspeed maintenance of constant airspeed.
When all this is done, you would see better than a 2:1 peak:valley current ratio in the various parts of the maneuvers.
5) Diameter is king: the more diameter you turn at a constant RPM & pitch, the more constant the airspeed of the rest of the airframe that is tagging along for the ride, irrespective of where the nose is.
6) Lightness is next to ... Awww, you knew that already

looking forward to it,
Dean P.

Dean,

Thanks for all the great tips.  We are making progress very quickly with this system.  I hope to have it all worked out by the end of the month.  As I said in earlier posts, we are quickly outrunning the abilities of the Oriental airframe.  It has been a great test bed to gather information. 

The controller I have is a Kontronik 3SL-80-6-18 which I used in my F5D's in 2000-2002.  I have (4) of these so I will be using them until I see the need to upgrade.  They are fantastic controllers!!  Harold Konrath was ahead of his time with the first of what is now the norm of sensorless controllers.  The governor mode in this controller seems to react quickly in bench tests and when used in some helis I have seen.  The motor runs amazingly smooth with this controller as well.  I am going to go out and test tonight with this controller and with my new JMP timer.  I am waiting on some props from APC, but if the hobby shop has a 10x5, 10x6, or 11x5.5 I will try those.  The JMP will allow me to throttle back and control the current.  I am going to up the static current from 32 amps to 35 amps to get a bit more power.  I have plenty of run time right now.  I am shooting for a 5.4 lap time & pull up on top.  A larger disc should give the pull, and less pitch or less rpm will slow it down.  I should have some more results by the end of the weekend.

Archie Adamisin

Muncie, Indiana 

The Genesis is presently using only 2600 mAH average per flight from its 4200 mAH batteries, and I think that 60 ounces could be flown with this setup.

Does he use AXI? and what prop?

Thanx, nice to know.

Hi Rudy,
Thanks for the confirming data.
I would even consider adding maybe 3/8" to 1/2" of diameter (12.5 X 6) when flying the slightly heavier ship.
That should up battery consumption to maybe 3000 ~3100 mAH.

Dean P.

Just wanted to dust off this old thread one more time.  Young Archie has been vying for a break in the weather - for the past couple of months - to prove-out the "final" power systems in this bird.  Since the test plane is the same size/slightly heavier than my pending "Swinger" (see that thread in the Classics forum) and he was proving out the system I intended to use I was GENUINELY interested in this session!

* Looks like I'll be using the 35-30-1250 Rimfire motor with Phoenix controller, JMP timer and 4Sx3000 pack, all to turn a 10x5E APC.  Indications are that the pack MIGHT be a little over-sized but that will have to wait until we get "campaigning" and really start to live/work with the system to determine whether we can use the next size smaller (2500's???).

* The Motor is only 2.5 oz, the battery around 11 oz.  Thus the total package is not unlike a typical 40 size unit typically used in a classic sized bird.

* Our experiences seem to parallel the E-Nobler from Germany that Bruno talked about a few months ago.  I am intrigued (maybe bewildered is a better word!) that we are achieving the success we have with such small components.  Time will tell whether it is truly successful.

* Nearest analogy I can draw is the early "Speed 600"/ 7-cell nicad power systems our RC friends pioneered - only to discover that they could get comparable performance from smaller "Speed 400" components still using 7 nicads but of smaller capacity and weight.  Probably the lesson is that the power & weight spiral works both ways (and weighs!)

* Meanwhile along with the Classic "Swinger" I am commiting myself to build a "real" CLPA bird using the next size larger Rimfre 35-36-1200 which will enable me to comfortably use an 11x5.5E prop.  For the intended design that will be a solid power-up versus the last slimer version of that design.

* BTW Archie also proved out the Brodak motor, reversed for firewall mounting, and using 3 cells.  3 cells actually looks viable in this power range (10x5E) - but the battery must be of higher capacity, and the tie-breaker may come down to simply the size & shape of the battery!

.....Consumption will hardly change from cool to warm weather, even though the RPM setting will change.

Hi Dean,
Can you please give your experience on those differences in A/h between cool and warm weather? can you quantify this? I would appreciate to read about that - and compare to what I noted.
Rgds, Thierry

Here are the Eagle Tree plots for (3) different motors.  All plots were using the Phoenix 60 controller in governor mode.  The 35-30-1250 plot had trouble on the RPM curve and I have omitted it from the curve because it really throughs it all off.  The lap time on all these plots were 5.15-5.2.  The only difference that I could tell between all these flights were the Brodak motor sounded different because it is 10 pole versus 14 pole on the Rim-Fires.  The overall power was the same.  It flew the best with the Rim-Fire 35-30-1250 because of the lighter weight.  The 35-36-1200 plots were taken on a day that it was windy 10-15 mph & 45 degrees.  The Brodak and 35-30-1250 plots were on a perfect stunt day 3-5 mph, but 35 degrees.  You can see the effect of the cold weather on the voltage as it increases over the flight.  I used hand warmers to keep the packs warm, but I had limited success with it.

The amazing points of interest here are the plots from the 35-36-1200 & 35-30-1250.  They used they same amount of power!  The motor geometry is completely different.

I have also attached a plot of the 35-36-1200 on a 11 x 5.5 APC which it used the least amount of battery, but almost made the Oriental un-flyable.  It wouldn't turn!!!  It pulled the hardest of the bunch.

With all this being said, there is still a lot to be fine tuned in this system to drop the capacity used by slowing the lap time, and possibly shortening the lines to 61'.  A lighter airframe would also help to save power.  Regardless, the 35-30 (2808 AXI) platform is viable for classic models and if I can get the capacity down, system weight would be in the 12 oz range which will make it completely interchangeable with glow power in models of this size.  The 35-36 (2814 AXI) platform is also a great size, but it has much higher output capabilities than the 34-30.  It would be better suited for 600 to 630 square inch birds up to 52 ounces.  Something like my Gemini Mk1 would be a perfect candidate for that motor size.

Enjoy!!

Archie Adamisin

Muncie, Indiana 

Now for the Million dollar questions:

1.) What is the relationship of motor performance to stack length & diameter?
2.) What is the relationship of Kt (in-oz/amp) to stack length or diameter?
3.) Do out-runners suffer from iron losses like in-runners do?
4.) Has anyone reached a maximum efficient rpm for an out-runner?
5.) What is the magic Kv number for 4S?
6.) What effect does the Kv have on Kt and current for given rpm?

Here are some pictures of the Brodak installed using the backplate mount.  Conversion was simple.  We lossened the set screws and moved the shaft until enough was left to put a wheel collar on.  The shaft sticking out the other side is sufficient to use the supplied collet assembly.  Big Art made the (3) bolt mounts for the Rim-Fires & the Brodak so that all are interchaneable.  The Oriental was ready to fly with a Brodak .40 before Uncle Dennis converted it to electric.  This is why the cowl is hollowed out on the bottom.  I would like to replace it with an uncut cowl to create better system cooling.

Oriental RTF weights per system:

Brodak w/Brodak (15C) 3S 4000's = 48 ozs
Rim-fire 35-36-1200 w/Maxx Amps (20C) 4S 3000's = 47 oz
Rim-Fire 35-30-1250 w/Maxx Amps (20C) 4S 3000's = 46 oz

Archie Adamisin
Muncie, Indiana

Hi Archie,
Excellent questions: some of which defy a simple answer. I'll try anyway.

1.) What is the relationship of motor performance to stack length & diameter?

More diameter means bigger pole face areas (for a given number of poles) and more torque (both because of the bigger areas and the larger radius) BUT it takes more wire length to go around that bigger face and that adds resistive or copper losses. More stack length means much the same, though the longer a stack is compared to how wide, the better use you get from the copper. (The wire wrapping around the ends is just added resistance, if you could somehow magically beam the current from the wires on one side of the pole face to the other.) Inrunners usually have better shapes in this regard. More about diameter in #3

2.) What is the relationship of Kt (in-oz/amp) to stack length or diameter?

They are bound to each other by physics! If Thomas Jefferson had won that all-important argument 200-something years ago, and we used a rational system of weights and measures, then you'd see that Kv (expressed in Volts per radian per second ) is exactly the same number as the Torque constant (expressed in Newton-Meters per Amp) But, we use feet, slugs and quarts, not to mention that we like to show Kv as the inverse of what was in my textbooks in school, so we use RPM/Volt. in any case, for the same weight of copper and the same magnets and iron, if Kv (RPM/Volt!) goes up 10% then the torque (in oz-in/Amp) goes down 10%.

3.) Do out-runners suffer from iron losses like in-runners do?

Yes, and moreso, because the magnetic path in iron or ferrite or whatever is longer in an outrunner. The motor design gurus are haggling over the reletive merits of high RPM (then geared) outrunners. There are additional losses with faster and faster pole-passing frequencies, and that's why motor diameters don't grow a whole bunch to get lower Kvs with more poles.    The holy grail is a motor geometry that needs no iron. This involves magnets with fields that make "U" turns. If you are terribly bored, go Google Halbach motors or magnets or ironless-slotless motor.

4.) Has anyone reached a maximum efficient rpm for an out-runner?

I don't understand the question.

5.) What is the magic Kv number for 4S?

'bout 900 with a governor, maybe a little lower if running at full throttle.

6.) What effect does the Kv have on Kt and current for given rpm?

See my lengthy answer to #2.

Dean

Hi again Archie,
I have another pesky question.
Does the airplane fly better with the 1 oz heavier  35-36-1200 Kv motor rather than the 35-30-1250 Kv? Even just a little?
Yes, they used the same total energy to fly, but the two datalogs show me that the motor with bigger magnets and bigger iron shows a slightly higher peak to valley current ratio. The one ounce heavier 35-36-1200 has an internal resistance of 41 milli-Ohms according to the datasheet, while the 35-30-1250 has 112 milli-Ohms. This means that if and when the governor "punches" the throttle, the 1200 motor will pull more current, more quickly, and so the momentary decrease in RPM that happens as you turn a corner gets quashed more quickly. That is, it pulls even harder just when needed. Besides, it will also be a little bit more efficient! That cancells out the extra power that gets used, apparently.

So what I'm asking is does the feel bear out what the calculation shows. Given two motors with similar Kv, does the lower resistance motor Stunt better?

Dean 

Dean:
Great stuff - thanks for taking the time for the answers.

How far the downward spiral - yes there are limits.  For instance, for instance, per "Uncle Deano's ROT for LiPo's" I would not commit to a 2500 mah pack unless I could CONSISTANTLY demonstrate per flight battery usage of < 1875 mah. Not quite ready to make that commitment - Archie is leaning that way. 

Comments on weight:  Way back in the 1970's GM learned that for every pound they could save in the body shell, the total car could get lighter by 3 lbs: lighter body allowed a lighter chassis, and then the powertrain could be made smaller.  I would not use the same fractions for CLPA but suspect a similar philosphy applies:  If we can save weight in the airframe then the powertrain components can get smaller: 1 oz savings becomes 1.xx savings for the total airframe because the motor, battery, wheels, landing gear, etc can all be made a little smaller.  Of course as the weight goes down another round of lightening is possible: Lighter total weight allows even lighter strucural weight eventually allowing smaller motor & battery.  Yes I agree there are practical limits - but unfortunately I am no where near those limits.  People routinely build comparable sized birds 6-8 oz lighter than I do!  But I use this only as an excercise showing why I think the weight can "spiral" down at least a lighter farther than I am.

Trouble is the batteries do not dial down in size, they change in steps.  Thus to safely save those 2 oz or so in the battery, I might have to save 6-8 oz in the airframe.   Possible - even probable for a light builder but a nightmare challenge for me!

You mentioned the governor "kick" pulling through a square corner.  The larger motor is about 1 oz heavier - certainly some of that weight is in the longer magnets and motor casing.  Acclerating that slightly larger mass of course require a bigger kick & current spike... how important do you think the physical mass of the motor shell is to that spike?  Do you think the shell of an outrunner be thinned or ventillated (made lighter) without adversely disturbing the magnetic flora & fawna???

I intend to have my assometer in full attention mode, watching for governor "kick" when I start flying the two motor choices we think will fit the Swinger!

Muddy Waters, but not the blues!

I was just speculationg that motor inertia = useless watts, less weight = less inertia = more watts applied to the problem at hand.


Oh heck, time to stop thinkin & talkin and start flyin..!

Hey, you gonna be at Toledo?  I'll let you buy me a...  root beer  (your welcome)

Archie,

With the 11x5.5 APC causing the slow turns you might want to revise the flap_elevator ratio to something less than 1:1. The older short couple designs were originally set up with around 30deg flap 45deg elevator. This is what we went to on the Still Stuka and the corner improved greatly. Other option that might be interesting to see is a 3 blade 10x5.5 or so maybe with a little undercamber to pull out of the corner.

Best,         Dennis

Archie,

With the 11x5.5 APC causing the slow turns you might want to revise the flap_elevator ratio to something less than 1:1. The older short couple designs were originally set up with around 30deg flap 45deg elevator. This is what we went to on the Still Stuka and the corner improved greatly. Other option that might be interesting to see is a 3 blade 10x5.5 or so maybe with a little undercamber to pull out of the corner.

Best,         Dennis

GOOD CATCH!

The Oriental was set-up from the get-go with 2/3:1 flap to elevator and clipped flaps to to help the too-short & too-small tail work as well as it possibly could.  Flies well with a 9" or 10" prop, but it starts going south with the 11" even with the MUCH better thrust.  Like Dean(?) suggested, it MIGHT get a little better if were to replace the prop with a MUCH lighter (probably reworked) wood prop - and I would consider that if this was a REAL airplane.  But it is only the test bed that has served amazingly well.  We have what we think we need to go forward with "real" birds.

One thing I have noticed about the two Orientals (one slimer and the electric) that I set-up last summer - the birds definitely tell you when they are not happy and give great feedback when when you make even small trim changes.  In short the Oriental remains a really good entry level stunter, that just starts falling short when you ask for Precision Aerobatics...  I'd recommend it in a heartbeat to a newbie or a "retread" getting back in the game.


one of the OTHER Dennis'

Dave,
I don't want to really admit it, but my battery cooling in my E-Nobler Arf was/is pretty miserable, but to be honest, my batteries were just warm after a flight. We are generally really not pushing our equipment in CL PA.

If I look at my data from the E-Nobler I am seeing about a 1V drop in battery voltage during level laps with currents in the 20 Amp range. I am looking at the end of a flight when the timer turns off and seeing how much the battery voltage jumps up with the current off.

That translates into a 20 Watt loss in the battery alone, or about 5 watts per cell (this was a 4s pack). If I were flying for 20 minutes like this maybe I would be really worried, but this is "only" over a 5 minute period.

It certainly doesn't hurt to get some air in there, but it doesn't really help the 2 cells in the center of the pack anyway (on the 5 minute timescale!). I think the main thing is to have them so that air can at least get around the surface of the pack (in other words, don't cover them in styrofoam or equivalent in an attempt to hold them in place).

What I am really trying to say is to not obsess too much    -- get some air back there and out, but it doesn't have to be a hurricane equivalent. The true test is that if the packs are warm to the touch just after you pull them out, you are cooling sufficiently. They should not be hot to the touch, that will probably decrease their expected lifetime.

 
 Thanks guys.  Problem probably solved.
 
     Dave

Hi Archie,
Thanks for the new info. Yes, the governor is nowhere near as tight: the peak to crest currents are 20% where the same prop on the 35-36 motor and CC was about 3:1!
I do like the idea of the low-voltage cutoff responding to any one cell in the pack, though. That will be good for saving packs from accidental abuse. Several outfits, like FMA, sell add-ons to do the same.

later,
Dean

Hi Alan,
I've gotten in the habit of checking each individual cell almost immediately post-flight.
The 3.0 V cutoff is quite conservative. I'll bet we never see anything as low as 3.3 V per cell, even when the batteries are used hard.

Dean

I guess one needs to be sure what kind of shutoff you have (or have enabled) on the ESC.
On my setup (CC Phoenix), I have what is called a "soft cutoff". It doesn't really shut power off, but slowly begins to lower the throttle to protect the battery.

With my RC planes, I have a hard cutoff, that actually turns the motor off when it is reached. You can get power back by throttling back to low throttle, so you can make it back (using low throttle) to the field if necessary. Of course you don't use such an extreme cutoff with 3D models or helicopters because you are almost always in a situation where there is no time to get to reduced throttle. Of course in CL we don't have the rearm option--unless you happen to accidentally be near where some timers blip the throttle to zero.

I think the real story is to make sure you know what is up with the battery before pushing the "go" button. I realize I need to check a bit better than I do now.

Thierry,
At least how my CC ESC works, the power to the motor is turned off, but not the power to the receiver (or timer in the case of CL). I don't think the JMP-2 would rearm the ESC except at the end of the flight when the JMP-2 blips the throttle.

Of course I may have misunderstood you.

John

I just finished an Oriental arf electric a couple of weeks ago.  I went to school on John Paris' glow oriental profile which he was very competitive in Advanced and now Expert in. He really liked the performance and I have watched it fly a number of times and been impressed. With an Evo .36 it is 48 ounces dry, 52 ounces ready to launch.

Dennis writes up the one he did here and as you note there have been a lot of electrons thru his planes since he did it. . His nephew now has it and has flown it a lot and refined it a good bit. He reports it a very good flier as well and can report on his setup.

Mine also flies extremely well. I was very surprised. It corners very pretty well, exits maneuvers dead flat without any waiver and is very stable. I powered mine with a Turnigy 3536 SK at 910 kv. I would not recommend a non SK motor from Turnigy. The SK's have larger bearings and I have had failures of non SK turnigy motors in stunt applications. Rick Sawicki and Dennis both also have used this motor in light weight applications. I most usually use a 2826/12 axi in my stunters but neither the power nor the weight of the axi was called for in this project. Rick had repowered a 2826 axi powered Geiske Nobler last year with the 3526SK and it came alive at the weight change. As a comparison I fly a T-rex with authority on a 2826/12 with a 12X6EP prop on 4S. It has a lot of guts. But the Oriental is a much smaller plane. It doesn't need the power.  I use a phoenix 45 esc (again to drop weight) and 4S aerowind 2800 mah packs. I am currently turning an apc 10x5E prop a bit north of 11K rpm on 63 ft lines to yield 5.25 sec laps. Draw is under 1900 mah per flight and everything is cool temp wise. My ready to launch weight is 49 ounces so I am considerably under the flying weight of the glow version. I used the stock bellcrank and leadouts and stock horns. The flap pushrod is stock and the elevator pushrod is carbon fiber with ball joints at each end. I used carbon fiber gear. The motor mount is Rick Sawicki's design, the details are in my T-Rex build thread on this forum.  I do use CA hinges. Have used them in everything less than .60 size ships for the last 6 years and will not go back. If I were going to do any more .60 size ships I would use them there too, but I'm going to stay T-Rex size and smaller. I have had a strega electric but have found T-Rex outflies it by such a large margin I can't make sense of flying that size any longer. My personal preferences your milage may differ. I have not found any of the truisms about CA hinges to be true. Again, just my experience. Since returning to modeling both RC and CL 7 years ago I have used traditional kleet/dubro hinges and CA both in RC and CL. Only hinge failures I have had are pin type. Never once a CA one. Never saw a CA one fail on RC at our club even when done wrong.  But again that is one of those opinion things. We all can have our own.  

Anyway, its a power system that works well in the bird. I have the ground clearance for larger props because I fly on a rough grass field at home. Could go to 12 inches if I wanted but at 910 kv would not want to and can't find a need to with the bird so far. Have fun. Its a great flier!

bob branch

(edited for motor model number noted in next two posts - branch)

Thanks Dennis you are right, 3536 SK. 

bob

I'm going to resurrect this thread, as I have an ARF Oriental on the way, and, much to a old flying buddy's chagrin, I am NOT going to put a glo engine in it!!
I have a 3020-950kv Exceed Rocket motor (360w rating)that I hope to employ for the O, unless you all think it won't work.
Plan a 4S 2500 pack, 10x5 prop, and could use advice on governors and timers. I'm considering the KR timer, since I think there is a slight chance of the prop being stopped suddenly (hey, you never know, right??!), and I hear it offers ESC protection in that unplanned event

The big "concern" for me is figuring out what the best way is to-
1. Mount the motor- Front mount seems preferred and makes sense to me, but pics say radial rear would be simpler.
2. Easy battery securing, change out, and ventilation.
3. Correct CG. I read two things-
    a) Battery centered on wing LE.
    b) 1" cut out of wing LE in fuse.

I know darn well the battery isn't 2" long, so that doesn't jive in my pea brain....I'm thinking maybe the first one was with a heavier motor??

I should add the disclaimer that I DO NOT have the plane in hand, so maybe some of these concerns are going to have obvious solutions when I get it, but any advise, heads-up, or other do's or dont's from those that have been there, and done that, would be REALLY appreciated.

I posted in this old thread as it seems to have the most pictures of install (thanks Archie!), and I likely will add my own as well here when I get rolling.

What say ye?

Regards,
Chris Behm

Thanks Joseph!
How coincidental that you have the same motor in your bird.
I really appreciate the pictures, it looks like there is plenty of room in there for the components.

Are you running the 860Kv motor? I blew up the one pic, and that is what it looks like to me.
I wonder how my 950Kv will work out on 4S?
Are you running a 10x5 or a larger diameter prop?

Any other gotcha's you think I could use besides what is mentioned in this thread (like the checking for secure mounting of the main gear, etc).

Thanks for the pics, perfect!

Kind Regards,
Chris B

Thanks Joseph.
From what I have read in this thread and others about the Oriental, it sounds like this plane prefers and turns better with a 10" prop.
That being said, I'll not worry too much about it, and maybe the 950kv I have will work well anyway then.

I appreciate all the pics, I know it is a pain, but they are very helpful, and will be to others as well I believe.

Kind Regards,
Chris

Thanks again for the pictures, Joseph!

I am wondering if you have much vibration with the back wall style mounting? I'm inclined to think a front mount would be better from a vibration standpoint. Maybe I am over thinking it? Lots of RC folks use this same style of mounting, and it is clearly easier to execute. I like the way the original engine rails are used.

My ARF "O" should be arriving today, too bad I won't make it home until Saturday!

Thanks for the battery compartment pics too!

Kind Regards,
Chris

Cool seeing this old thread resurrected.

The Oriental that started this thread was originally built with a front mount, then changed to a rear mount that made it easier to try at least 5 different motors.  The "mule" also used at least a 1/2 dozen size props, 4 different ESC's 3-4 different batteries and two timers.  It was also flown with & without an Eagle Tree data logger.  We learned LOTS from this bird

Unfortunately it was crashed before we got around to the pusher prop...

I think that at least initially, I'll opt for the back mount and go from there.
In theory, if either the motor or prop is slightly off balance, I would think a front mounting would help keep it under control.
We can balance the props, less likely to do the right thing with a lopping motor (me, anyway).

I'll hope for the best.

Using to start-
Exceed 3020-950,
4S @ 2500 Lipo's,
10x5 APC E prop
ESC-TBD, thinking CC Ice Lite 50A
Timer- TBD...

I can't wait to get home and open the box with the O'....

Regards,
Chris

Good to know, thank you Dennis!

I'm a little late getting here. (I was also on vacation), but the 860 version or the 950 version are both fine. Pick one and use it. Those motors are very happy with the 11x5.5 APC thin electric pusher props on them. They are 3 bearing motors and most guys here are rear mounting them. A standard set of cheep e-bay bearings cost about $5 for that motor and some guys here have over 100 flights on the stock bearings. Like I've said a few times before Its a $20 motor don't get too hung up on the bearings. At 100 flights replace them and make the motor new again(Glow plugs usually don't last 100 flights and they cost around $5 these days) or toss the motor when they actually fail and buy a new one. Some guys here are pulling 50-53 ounce Caprice sized planes with those motors so they work for similar sized planes.

A local sun bird from Wisconsin showed up to our flying site recently with and Arftrick Oriental....with a Power 15, 4 cell. It had tons of static thrust at launch. It had been modified slightly in the rudder section but actually presented better with a 62 Ares rudder/fin. I was impressed.

I will use the normally sealed compartment above the "tank" compartment for the ESC and KR timer.
The battery will reside below that, in the normally "tank" compartment.

Each of these two areas will get its own inlet and outlet for air.
I have not yet decided if I will separate them with some 1/64 ply or not.
I might have to do a test run with and without, my guess is that most of the heat will be from the battery, and I might try to keep the ESC a little cooler if I can.

I added scoops to the cowl. This should keep the motor cool.

The outlets are a huge vent on the tank (battery) compartment hatch, and some cute little "exhaust pipes" above the engine beams for the ESC
Pics of progress.

I tried to be creative and made some mock engine exhausts that serve as outlet vents for the ESC compartment...I know, its kinda far back for a V engine! Oh well.
Pics tell the story.
I will "run" the engine by marking the inside of those exhaust pipes black with a felt marker before the maiden, I promise.

Thanks Crist-
Coming from a craftsman such as yourself, this is a nice compliment!

I'm looking forward to completing this plane and getting it in the air. I fly with a group that is pro glo power, I'm sure I will be getting some ribbing from them. However coming from RC sailplanes, E-power in C/L is a much more natural selection, and I won't have to become a motorhead.
That being said, last weekend I re-attained a couple of my old 1/2a C/L planes from 20 years ago that I had donated to a friend for his kids (which of course they never flew). Even scored a NIB .049 Medallion that he'd bought, and got back an old .19 Torpedo Green head, which I had never run.

Hope to work on the Oriental a bit more this weekend!

Thanks, Dennis!

I have a few more pics of progress.
At this point I have figured out the tank compartment installation, and the wing and tail are now glued on with CA, to be epoxied and a fillet added next. She's nearing completion! I'm a wee bit excited.

Pics of the tank area and above for the ESC. I made an extension for the KR timer. I wanted to be able to unplug the switch, and plug in the programmer, without digging out the timer from below(inverted) the battery tray. A "peep-hole" allows me to count the flashes with the battery not secured. I took the picture of the tray before this was drilled.

There will be a patch of velcro at the back of the tank compartment to keep the aft end of the battery from shifting. I might also tack a foam block on the outboard side of the fuse for it to rest on during flight.

I think this will work!

R,
Chris

Here is the battery inside the tank compartment.

Two different brands of batteries-
Hyperion 4S2800 HV(4.35V/cell)30C/60C----$42.95, free shipping over $100, 2 days transit.
260 grams.

Thunder Power 4S2700 (4.2V/cell)25C/50C---$54.92, $13 shipping from Atlanta, GA, backordered for 3 weeks. Second order cancelled.
255 grams

Guess which battery is likely to be my go-to now?

R,
Chris

Chris,
I have mine balanced at 6" from the trailing edge and I think it would corner better if it were further back like 5 3/4". But 6 should be a good starting point. I had the add 3/4 of an once on mine to get it to 6".
Hope that helps,
Joe

Correct

I flew the maiden flight of the Oriental yesterday and I am happy to report it all seemed to work well!
The wing has a substantial twist to it, and the direction was safe (rolling out), so it pulled like a mule, but flew very outboard tip down, and inboard tip down inverted. The gun and some cranking should get that sorted.

The powertrain worked perfectly. I'm very happy with that. After tweaks to the prop and motor speed, I had flown 2 one minute flights and a 2m30s flight on the TP ProLite 2700. That battery took 1108ma.
The last two flights were 2m30s each on the Hyperion HV2800 (rated at 2500 at regular voltage, and that's where I'm running it), and it took 1583ma. About 316ma/minute. So, I'm looking at 70% discharge for a 5m30-5m45s flight. I'm pretty happy about that. Average amp draw is 18.9x amps, that seems pretty reasonable.

The plane is pretty nose heavy, and the motor is not heavy. If I were to build out another ARF like this, I would definitely look towards cutting into the wing LE and making a tunnel through the fuse bulkhead at the wing LE to get the battery back some. I knew I should have done that, I'm a bit disappointed that I didn't trust my instincts building this. Oh well, next time. I'm not going to look back.

For this particular model, yesterday I hogged out some of the I/C engine bearers, and also cut open my compartment behind the tail wheel mount and put 3/4oz in there. That should help with the CG.
It might need more, I haven't measured it yet. I will work on the wing twist and try to get that worked out, otherwise the CG will be of little consequence.

I have a couple other odds and ends to do. Bush the main wheels, add the canopy, decals, etc. Its definitely a pretty plane and I can get used to not having to clean castor off of the plane! The control system is very smooth and free, I'm happy with my install as this is only my second build. And since I revamped the entire control system, I think it was worth it if I can get the warp out of the wing. It should last longer than the plane does. Learning is fun.

All in all, the ARF is a beautiful model, and a great value. I would probably try to find an ARC instead next time, just because with all the mods that I would make, its hard to keep the model pristine. Better to cover it after all is done I think, and to also have a unique looking model. Still, a great value!
I'm looking forward to flying this a lot, it should be a lot of fun.

Thanks to Joe and others along the way for all the pointers.

Another happy and successful outting with the Or Eee Ental....

We have the wing ALMOST straight now, just ever so slightly tip down....
I took off the training wheel time of 2m30s and instead set the timer to 5m30s so that my veteran flying buddy could run a full pattern with it.
He's a hard core glow fuel guy, and guess what? He LOVES the way the plane flies and corners. He gets a big kick out of hearing the "boost" from the timer after a hard corner on the square maneuvers. He's all smiles.

The plane pulls really hard. So far we have worked on straightening the wing, and added some tail weight to get the CG back a bit. I have 3/4oz back there, and with the 2500/2700 4S packs, its still a bit nose heavy.
It also has some slight hinging tendencies in the square corners, and once we get the wing flat upright and inverted we will see about moving the leadouts forward a bit. I have lessened the motor thrust to about 1.5 degrees, and its still pulls well in the overheads.

I'm replacing 1650ma to the pack after a full pattern on a 5m30s flight. Because of this economy (18a average draw), I might try a Thunder Power 2100 pack. Its about 2oz lighter and I might be able to pull that tail weight out too?
http://stunthanger.com/smf/index.php/topic,40577.0.html

Anyhow, enjoying the plane and the next conversion would be a snap for me I think. Thanks for all the help.

R,
Chris

Great info, Peter...
My C/L mentor thinks we need to slow down the oriental also, and we have about a 5.0 second lap on 60' lines.
What prop are you turning? I think I have a 10x5 APC tractor on mine. I may take a few turns off of it, or maybe try a 10x4.5 wood prop.

Wow, you are running an 11x5 pusher, I'll have to check the Kv on that 15 motor you're running. It is likely a bit lower kv than mine I would guess. And I'm assuming you're running a 4s pack.
R,
Chris

Thanks Peter-

That's all very similar to what I have, although you are drawing more amperage with the 11" prop.
My motor is 950kv, I'm running a pair of 4S Hyperion 2500's and a pair of Thunder Power 4s ProLite 2700's, but I'm only putting back in about 1650ma after a 5m30s flight.
That's on a 10x5 prop.
In fact, I might drop down to the next size battery to save some grams up front, along with a smaller ESC. I think I might be able to get the 3/4oz weight out of the tail then, and maybe save @3 oz total. Then I would be in at 45oz.

R,
Chris