Daily Archives: July 28, 2011

9 posts

Club Meeting – Bomb Drop!

By Jim Bonnardel 

Filed 360   Click the pic for a 360 view of the field.


Saturday, July 30th is the club meeting, and fun-fly event.

This month Jim Bonnardel is hosting a bomb drop.  All of the bombs, and drop devices  are provided.  You use your aircraft of choice to drop the bomb over the target.  Mechanical bomb releases are not allowed, everyone must use the same style drop devices, which are provided.  You do not need an empty channel.  The sign-up sheet will be out at 08:00, and we will go in the order of sign up.  If you want to beat the noon wind, get there EARLY to sign up EARLY.

John at DHW ( http://www.discounthobbywarehouse.com ) besides taking good care of us for the place prizes, stepped up and fully sponsored a bonus prize. He has found something he personally uses, and thinks EVERY pilot should have one. He donated one as a bonus!  Thanks John!  Come down, participate, and see what the BONUS PRIZE is!

The club meeting is scheduled to begin at 10:00,  and the bombs start dropping for score as soon as the meeting is over, but  Jim will be at the field early for signups, serving coffee,  and letting folks get all the practice in they want.

Jim is also having two monster subway sandwiches delivered down to the field with standard goodies, so be sure your Saturday, July 30th calendar is wide open.  You do not want to miss this event!

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Electroglide Report from 7/16/2011

The next Electroglide is scheduled for August 20th. Come join the fun!

Here are the results:

Standard Class –Stock Radians

Bob Anson            50 (10)       42       69 (30)       89 (30)       250
Norm Arndt         58 (20)    52 (20)      42              57           209
Bob Stinson         54 (30)    44 (20)      34           72 (20)       204
Vince Gonsowski     27         40(20)     49 (10)         22           138
Don Wemple        52 (20)        22          40               0            114
Terry Thoman        16             17        41 (20)         25            99

Open Class –2-cell, small outrunner, any design

Pedro Brantuas    43 (20)     32 (10)    31 (10)       68 (10)       174

 

Some of the landing action. Pics by Jim B.

Landing 1

Landing 2

Landing 3

Pylon Racing at Weedwackers

 

June Pylon Group

A sincere thank you to all who attended……………….and for those who could not attend…….this is part of what you missed!  Results.

 

Lunch Ladies

Judy brought condiments, table  cloths, and crab linguini salad.  Robin and I did the burgers, dogs, drinks, and off color comments.  Wayne’s daughter Marissa made the outstanding brownies.  It was all the racers and friends that made the day!
Thanks again
Lance

 

MUSticks in Race

 

 

Gary Fenelli joined us for his first T-28 race and he loved it.  Here are a couple videos he took during the day:

http://sharing.theflip.com/session/6246fffdb5007e226b89449c90c489da/video/98199491

http://sharing.theflip.com/session/3ec270c084d80e905b3a8af5dfc642d3/video/98197701

 

T-28s

 

Meanwhile, back at the Bay. . .

This pic is at the end of the runway, near station #2 at Mission Bay.  We had just finished the main event for May, and I (Jim) was the first to land.  Lance came in a bit hot, went long down the runway, and our planes tangled a bit.  This is how they were found at the end of the runway:

Jim & Lance Planes

 

 

Jim and I (Bob) did some testing this morning at the SEFSD field.  I have attached the results in excel and a PDF copy to share with all MUStick racers.  Not all cells are filled in but we got enough info to see what works best on our planes and to know what we need for the next time we do some testing.

MUStick Tuning Data

 

Menifee Valley Flyers T-28 Pylon Race with airborne camera by Otto Dieffenbach:

http://www.youtube.com/watch?v=_8TkHW4R7zc

 

Get ready to rumble!……………….Next race is Sunday July 31st at Miramar. Pilots meeting 0930…Heats start at 1000……..Please try to be on time. I have included an invitation to the T-28 racers from the Menifee club via Otto Dieffenbach. They can reach me @ 858-271-4430. The race at Santee was a huge success thanks in no small part to Lance and crew! The racing was exciting and NO CARNAGE! Miramar will present a different field and a different challenge……Should be FUN!

HOW I BOUGHT THE ITALIAN “CMG” 0.039 CU IN DIESEL ENGINE

THE GERMAN TROUPS, USING ITALIAN FORCED LABOR GANGS, HAD SPENT NINE MONTHS FORTIFYING A NATURAL EAST-WEST STRATEGIC APPENINE MOUNTAIN RIDGE WITH HUNDREDS OF MG BUNKERS, CAVES AND HIGH POINT LOOK OUTS. IT HELD FOR NINE MONTHS UNTIL WE “CAUGHT THEM NAPPING” IN A SURPRISE ATTACK AFTER MAKING A STEEP 3000 FOOT ALPINE CLIMB.
HAVING SUCCEEDED IN THE ATTACK THE GERMANS FINNALY SURRENDERED APRIL 24 IN AULLA, ITALY.

 

GENERAL MARK CLARK SUGGESTED TO OUR REGIMENTAL COMMANDER TO GIVE US A WELL EARNED LEAVE. A BUDDY AND I DECIDED TO HITCH-HIKE TO SWITZERLAND.
THE FIRST LEG OF OUR JOUNEY WAS TO HITCH A RIDE ON A
B-17 FROM THE PISA AIR BASE TO MILAN. THE B-17 CREWS WERE HAPPY TO SIGN US UP ON THEIR FLIGHT MANIFEST TO LOG SOME HOURS TO COLLECT THEIR FLIGHT PAY.  THAT RIDE WAS A BARF-BAG EVENT!  FROM MILAN TO THE TRAIN STATION WAS A SHORT “HITCH” ON A GI SUPPLY TRUCK.  HOWEVER, ALONG THE STREET TO THE STATION WAS A HOBBY SHOP! BEING A MODELER I STOPPED TO LOOK AT WHAT THE ITALIANS WERE USING FOR ENGINES. THEY SHOWED ME ONLY UNFAMILIAR (TO ME) DEISEL ENGINES. AFTER EXAMINING SEVERAL THE PROPRIETER ASKED ME IF I HAD ANY U. S. CIGARETTES. I HAD TWO PACKS; THEN HE MADE ME AN OFFER I COULD NOT PASS!  I GOT TWO ENGINES –ONE PACK EACH!!  I GAVE A FRIEND, YEARS LATER, THE LARGER OF THE TWO ENGINES. THE OTHER IS A “ C.W.G.” S/N 14.

SO, OFF TO SWITZERLAND WHERE THE MAJOR 5-STAR HOTELS OFFERED GIs $20 ROOM RATES AS “THANKS”!

Dave's Diesel 2

Direct or Geared?

 

The original article appears in the German magazine FMT,  issue Eight of 2011 by author Andreas Maurer on pages 28 through 31.  It is accompanied by many color photos.  FMT is the largest of the German Language magazines covering Radio Controlled Model Airplanes (extending from Germany into Austria and Switzerland),  it covers just about every aspect of RC flight.  As such,  some articles such as this one go into more background details then they would in a more specialized publication.

This is not an authorized translation,  the constraints of a precise legally defendable conversion were set aside to make it as readable as a comparable write up in American English,  without masking it’s Germanic origins.  It’s just a hobby to make it accessible to the members of the Silent Electric Fliers of San Diego.  The original Author made some glaring material ruining mistakes and errors by admission!  We have some of the most knowledgeable Electric Powered RC pilots and manufacturers in the world among the San Diego Silent Electric Fliers,  some completely new to RC flight members,  and some converts from reciprocating power too.  In a big change from previous translations,  only  portions were translated,  to cut translation time.  The translator, a former and future Shame of the Club,  has addressed some glaring errors making this a new article.

 While researching how to make the best of my new Multiplex Fun Cub I was disgusted at what even the not dependent on manufacturer’s advertising Internet authors left out.  And at the disparaging stuff (like foam so soft it can’t be expected to last more then a weekend) routinely left out of some FMT model tests.  I am incensed that the Editor at FMT did not weed out some of the content of the article.  Usually I do  a formal,  legally correct,  language conversion,  not this time!

Begin the Article
Motivation for the conversion was the noise from the engine of the ten foot wingspan airplane.  It was either convert to something quieter,  or quit flying it at the field on Sundays.

Since the Su-26 from Hanger 9 is relatively light the conversion seemed plausible.  There were already LiPo Batteries in the size 6S 5000 mAh on hand.  Four of them together results in 12S 10,000 mAh.  After researching things it was decided on Scorpion Motors,  as distributed in Germany by Ringel Modelbau.  The manufacturer makes a suitable program for their motors available.  It kicked out the HK555-180.  It would deliver the same performance as a DA85 oil spewing,  vibrating,  howling engine.  A simple calculation indicated that the additional weight over a engine would be about 2.2 pounds.  Right here you need to question the understanding of the person doing the conversion.  To quote the German F5B World Champion Rafl Fickensicherer as previously published in an FMT article translated and forwarded;  Not including the fuel that the engine fraction so willingly omits.

Just for the fun of it I did the calculations for combination using a transmission.  To my surprise a HK4035-800 with a 5:1 transmission provides the same performance as direct drive at 15% less weight.  I take that that here the weight difference is just the direct drive motor verses the geared motor.  The whole package has to be evaluated to be valid,  something the started with combustion types still don’t seem to have in grip.  If that is really so,  would be determined.

From Theory to Practice
The following candidates were thrown in the ring:
Direct drive Scorpion S5545-180,  20 poles,  live weight with mounting cross-plate 1.120 gram,  certified for operation on 12S LiPo,  maximum 4,500 Watts continuous.
Transmission Scorpion HK4035-800 with Reisenauer-Motor Chief 5:1,  8 poles,  overall weight with transmission and motor cross-mount 620 gram,  certified for operation on 12S LiPo,  the transmission maximum is 4000 Watts continuos,  the motor 4,200 Watts. 
That’s watts- in folks,  not what is delivered to the output!  We wouldn’t rate a fuel engine’s output by measuring the fuel consumed,  but,  at least because it’s easy to measure and standard,  that is typical for electric motors.

The score is already 1 to nothing for the transmission combination.  500 grams less weight by almost the same performance.  This is misleading,  no motor vehicle publication would omit/forget that output through a transmission must include the additional losses in the gear train.  See the term horse power at the rear wheels.

Let’s take a better look at the transmission.  It’s a planetary transmission (standard for decades within automotive automatic transmissions) with plasma hardened steel wheels and a titanium shaft.  The planet gears have needle bearings.  Planetary gear transmissions have the highest energy transfer density per volume and the best efficiency for concentric output.  The output shaft has double angles bearings diameter 32 mm.  The transmission itself has a diameter of 38.5 mm,  examination of it leaves an impression of solidity.  According to the transmission manufacturer if the gearbox was correctly lubricated they has never been a failure,  not even by crashing or wear.  It’s almost unbelievable that 5,5 horse power can be set free here.

Assembling the transmission to the motor turned out to be simple.  The input shaft would be attached with High-Strength Loctite in the correct extension on the motor shaft.  The motor mount attached and assembly is complete.  Since the transmission is already on the upper limit of it’s capacity,  actually a little over,  that glued input shaft could be a weak point.  Help was provided by a jeweler who routinely makes ultra small laser welds.  That worked great here.  Like how many of us have access to that type of exotic welding?  That just blew any general purpose open to the ordinary public comparison.  Still,  if the transmission manufacturer knows it lasts with Loctite,  he must be right.  It’s important to point out that only a motor with a 6 mm output shaft may be used.  And,  the lousy manufacturing tolerances of cheap motors plus sloppy bearings won’t work with a precision piece of equipment like this transmission.

Into the Model
Conversion of the model was more difficult.  Due to the difference in weight of the motors getting the balance right required that the position of the batteries had to be variable.  And the construction of the model precluded installing the batteries in one piece.  The muffler of the combustion engine was underneath the landing gear shock absorber,  which placed it relatively high.  Therefore two batteries were under the cowl,  two more further aft.

In comparison the instillation of the motors was easier.  The direct drive motor went on a fiberglass reinforced plywood box.  Another construction was used for the transmission combination.

The motor controller went on top of the motor mount box.  Since it wouldn’t fit with the cooling fins in line with the incoming airflow,  a duct was formed to direct the airflow over it.  The huge opening in front was then nearly closed off,  only a ring around the motor and the inlet for the controler cooling was left open.  This is frequently required for effective electric motor use in models of airplanes originally equipped with radial engines. Otherwise that big cupped opening performs just like the references out of the aerodynamic fluid engineering as a maximum drag device.

So,  with that fully equipped the model weighs including the direct drive motor exactly 11,010 gram,  or 1,100 gram more then the engine combination.  What a glaring by omission misrepresentation of weight!  It leaves out the weight of the required fuel for a combustion power plant.  Not to mention the slow but unavoidable increase in weight as the thing gets soaked in oil…

A short trial run in the shop with full gas (make that full ampere) without a propeller made for questions.  After a few sections of floored the transmission developed a temperature of 60 C.  A phone call to the manufacturer brought the answer.  The warmth came from the motor.  The motor should not be run without the propeller.  First off that omits the cooling,  second at the high RPM the motor controller makes the mistake of double clocking,  the resulting waste energy turns into heat.  The only way to overheat the transmission is to over fill it with lubrication,  but 60 C is otherwise ok.  Was the builder stupid?  Nobody would test an automotive transmission by disconnecting the driveshaft and flooring the engine.  The manufacturer’s of electric motors always include the warning to not run an electric motor without load as the resulting high RPM may easily completely exceed the capacity of the bearings,  ruining them before they ever get a chance to show their stuff.  If this wasn’t a common mistake on the part of the fuel burner pilots I’d be convinced this guy had a screw lose.

Which Propeller
The next question was the correct propeller.  Mr. Reisenauer desperately recommended the new wood props from Fiala.  They have a clearly better efficiency then the usual propellers,  for E-motors very important. 

Back when we flew with heavy, low powered can motors the RPM of electric motors was so much lower then the engines that,  due to the available power being so low,  special propellers were the only way to get our stuff to fly at all.  In a sense the special E-props we are today using for very slow flight still represent that,  propellers are them selves an airfoil,  which must be matched to the demands of the whole assembly.  What a propeller sees is the RPM it is turning a verses the airspeed,  how the torque arrived there is of no consequence.  If an electric motor under load turns the speed the propeller is constructed for,  it has exactly the same performance as if an engine were turning it.  There is still the difference that electric motors may still have flatter torque over changing RPM (such as  when airspeed during a maneuver changes) ratings,  with the result that a different propeller may perform differently as the rotational speed varies differently with the source.  Take note of a previously forwarded translation about developments within the highest Acrobatics class,  F4A,  where the electric motor manufacturers are designing their motors and controllers both to function at just the same speed as the current (now losing ground but by no means out) combustion engines. 

The combustion guys seem to very slow to catch on.  I routinely get up to a hundred flights out of my folding reinforced plastic propellers. If you are wondering why my seemingly ratty looking airplanes outperform yours,  it includes a few minutes with fine sanding paper tuning up my props.   At the flying field former “power” pilots often cannot be convinced to even debur propellers,  even when the flashing is obvious.  They broke their wood ones so often and the erosion from debris always did it before for them,  “why bother now” seems to be their opposition ignorance.

From theoretical considerations the sizes 24X14 and 23X16 should deliver good results. In addition I wanted to try the already on hand from the DA85 27X12 Elster and 24X12 Engle Super Silence propellers.  That DA stands for Desert Aircraft filthy, stinking,  lubricant slinging,  shakes so hard it blurs,  combustion things.  It’s a large size consummate with moving a ten foot wing span all out aerobatics RC airplane,  and a good quality one at that.  Those props,  described in inches,  which was once a common measurement in Old Germany and is still used there for pipe,  represent a large investment.  At that price and quality the props are jewels that require no deburing.

The Engel 24X10 had the best results on the ground,  particularly with the direct drive motor.  It was otherwise in the air.  It required the most energy in the air and had the worst dynamics.  When used on direct drive it drew down 4,100 mAh.  When used with the transmission combination it took about 3,500 mAh to fill up.  Due to the RPM it was also the loudest in the test.  I take it that he is flying a set routing,  common to among other things,  F4A.  It may very well be that he set out to match the energy requirements to the specific duration,  common among competition pilots to which,  despite his gaps in the electric power understanding,  Mr. Maurer no doubt belongs to.

It was different with the Fiala 24X14.  On the ground it took more power then the Engel,  in the air it was much more efficient and gave terrific dynamics.  The vertical climb was phenomenal,  apparently the model weighs nothing.  You notice that you need much less adjustment with the gas hand.  It’s amps! That was the case with both propulsion concepts although the transmission one drew less power.  After an eight minute flight the direct propulsion required about 3,600 mAh,  the transmission one 3,200 mAh.  It was analogues with the Fiala 23X16 although it drew more power.  At full voltage it drew (170) amps.  When hovering you could sometimes hear the prop stall.  With both motors seem annoyed,  the pitch is too high.

The Elster 27X12 was disappointing.  At maximum voltage the direct drive drew (170) amps,  the upper limit of the motor controller.  If it was desired to not draw the batteries down more then 80% an eight minute flight was not possible.  Due to a very wide flange the prop could not be tested on the transmission as only 4mm of the output shaft stuck out. 

If this section reads like a propeller test it’s because of the tremendous influence a propeller has on flight performance.  There is more experimentation required with electric then fuel burners.  As I note in my book “So You Want to Fly RC”  nobody flies dynos,  you have to try it.

The Winners Honor
So who won?  It’s clear cut,  if you want a high efficiency,  super light and problem less operation,  get the transmission combination.  Just be willing to accept the Euro150/$225 higher expense.  You hardly hear the transmission,  in the air even less.  But if money is more important,  get the direct drive.  Talk to Steve Neu about an Outrunner Killer combination he has.
Some comments to the rest of the program.  The Hacker motor controller (great stuff) made the maximum out of the motors.  May I quote Steve Neu “you get what you pay for”.  Don’t expect the same performance out of the cheap stuff.  I was amazed at the improved performance of even an inexpensive 45 gram outrunner when my finances finally allowed the use of a motor controller where I could set the lead from the general purpose works for anything to correct for the outrunner.

End

The Next Big Thing-Step 7

Of course it COULD be that the Scorpion Commanders’ only speak in an obscure Malyasian dialect and our little Italian friend , Arduino, just cannot understand Bahasa.  Then again, it could be, Gan,Guan,Kejai,Min,Wu,Xiang,or Yue, as well.  (All of these Chinese dialects are Greek to me.)

In the mean time please enjoy the Tricopter YouTube video below. Watch as this wildman land this T-Copter in his hand!  He HAS to, it has no landing gear and the pusher-props are on the BOTTOM!!!  Can you say “lawn mower” ?

 

http://www.youtube.com/watch?v=LSGIlnZhZdQ&feature=player_embedded  (Sorry, this video removed – Ed)

 

This is amusing .

http://www.rcgroups.com/multi-rotor-helis-659/

 

Picture overload here

http://www.rcgroups.com/forums/thumbgallery.php?t=1261382&do=threadgallery

 

Until next month, on The Next Big Thing .

Rocket Bob Kreutzer

Editor’s Notebook for July 28, 2011

9  ICE HV 120 NOTICE    July 25, 2011

Hello all,??While Castle takes all controller failures seriously, many have felt that our response to the incidences of failures in our Phoenix Ice 120HV was taking too long. We didn’t make any official statements as we couldn’t identify any particular pattern or cause for the failures. Our Repair Dept. keeps track of our returns – for any reason — and the returns of the 120HV were actually very low; less than 3%.  We generally see more than that rate of return just from crash damage unrelated to the controllers. Given that we’ve produced more than 10,000 of these controllers, a low percentage of failure still results in a lot of upset customers.
We’ve recently determined that some, again some, setups stress particular components in a way that causes the controllers to fail instantly.  The failure mode allows a complete short circuit to occur.  Our controllers are designed to carry high currents with as little resistance as possible.  This is advantageous when the controllers are operating properly, but this leads to extreme currents and heat when the controllers fail.  As the ICE controllers are encapsulated in metal heatsinks, this heat is further concentrated such that physical injuries or property damage may occur.
Our engineers have tested a hardware modification that greatly reduces the risk of this particular failure.  We do not recommend using Phoenix Ice 12HV controllers until they have been modified to this new standard.??Please return any 120HV controllers that you may have for one that has this modification.  There will be no charge for this exchange.
Please advise anyone using a 120HV controller of this notice.

REPLACEMENT PROCEDURE
Click this link and follow the directions to process your return.
North American customers please ship to Castle in Kansas via a traceable delivery service:
CASTLE CREATIONS, INC?120HV SERVICE / Service Department ?540 N.ROGERS RD. ?OLATHE, KS 66062   

Please be sure to include a copy of the order confirmation in your package.
NOTE: For purposes of fast turnaround, you will be sent another Phoenix Ice HV 120 controller. Remove all connectors, etc. from your ESC before shipping as they will not be returned with your replacement controller.
Our Technical Support and Repair staff do not have any additional information, calling them will only lead to additional frustration for all involved.  We will advise you via email of the expected shipment date for your return.

We apologize for any problems this matter may have caused, and we hope that our candor and willingness to repair these controllers will help maintain your trust in our products and service.

Thanks,

Team Castle

 

John & Frank