Monthly Archives: January 2015

4 posts

Brad’s Corner

Brad  Membership day at the field on Jan 10th was a big success! We had around 30 people meet with Isabel and Paul to get their membership on track. Quite a few stuck around for lunch and it was a great day for flying.  Please remember to wear your 2015 badge on your person while flying , and try not to get upset when someone asks you to wear it if needed. Remember, this is YOUR club and no one will hold it against a paid member who is asking to see a badge.

 That being said, If you haven’t renewed yet – Now is the time!   Non-members are only allowed to fly (with AMA) 3 times in a calendar year, and must be signed in to the guest log with a member as a sponsor.


 There have been a few recent situations where a non-member, non-AMA person has felt he could Bully us into letting them fly at our site because it is “City Property”. Please don’t take the bait and escalate the situation. We are right – they are wrong. Kindly explain to them that we rent the property and every member has signed a legal waiver of liability with San Diego to use the site. The city has posted signs at the access gate that state “Authorized Vehicles only” and ” Membership required” at the access gate and at each gate on the flight line. If they still attempt to fly, we can call the police and the rangers to have them removed from the site. If they get really belligerent, attempt to get a photo of them and their license plate in case we need it. We will write the rangers emergency contact number on the back of the clubs information board.


 At the next Board meeting we will be discussing and approving the 2015 event calendar. There were a lot of great events organized by Jim last year that we plan to carry over to 2015. Returning will be the FPV Races, Poker Fun Fly, Bomb Drop, ” Don’t spill the beans”, Rotor Day, Jet Day, and Foamy Frenzy. New this year will be events in support of International drone day on March 14th.  There are a couple of months left and I would like some feedback from club members of any event you have been thinking of that can be enjoyed by general flyers (no special skill required). I am also looking for a couple of people that are interested in being more active in the club to let us know you would like to be involved in setting up or even running some of the events. Jim has done an AMAZING job, but I don’t want to wear him out and it would be nice if he could participate in a few events himself this year…
We currently have not planned any full day events, so there will be open flying before and after.


 There are quite a few new members already this year. I challenge each of the more ” SEASONED”  flyers to remember their early challenges and share some of their experience with the incoming generation. Whether helping to educate them on batteries and their safe use / building suggestions/ or help with their first flights to success, I know they will value your time. Please don’t be afraid to ask if they need help, sometimes it’s just what they need and are hesitant themselves to ask.


 Last, One of our most experienced members had a serious lipo fire recently, there were also a few vehicles damaged by fires at the field last year. I would like everyone to take a few moments to frankly evaluate how they have been charging and storing their batteries. Current charging technologies are pretty good at detecting faults, but they are far from perfect and even a small fire can be devastating.  [Let’s not get complacent, it can happen to any of us.  Want proof, click here.]


Here’s to a great year!!


Brad Bender

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2014 F5B world Championships, Turnau, Austria


*Monday it was Lenny Keer of Colorado’s turn to get a gremlin, a flap servo decided to not travel smoothly, he replaced the servo that evening.




Jeff Giving Launch to Steve’s plane


*Tue. It was Jeff’s turn to find a gremlin in that his prop kept coming off during launch, EZ to fix with a new dab of Locktite.


*Wed. Patrick Liddy of Pasadena shows up with his parents after getting a two week pass from High School to attend the Worlds as our F5B Junior representative. Patrick is certainly an up & coming competition pilot and flew several extremely good rounds that even posted in the top 25% of all Senior rounds for the day several times. Of course we were all rooting for him & urged him on to go faster in the Distance task as that is known as the most important of the three tasks. The other two tasks are viewed as “Opportunities to Lose Points” by the World Class Pilots!


On Patrick’s first launch in practice his prop came off too! Then Lenny finds erratic behavior on another flap servo! He spends the evening inspecting and re- insulating all of his planes servo plugs. He must have done a good job, as his Gremlins are now Banished!


*Thur. This is the first Day of the two day Turnau Cup, a warm-up event before the Worlds which start on Mon. the 25th to shake out any bugs in the operations of the two Scoring & Timing crews on the field. The field is a full sized Glider Port for the Turnau Gliding Club and by our standards gorgeous in that it is very smooth grass and wide open, until of course you put both the glider and pylon racing events side by side! There was of course a wide buffer between the two events, about 250-350 meters, but there was still some complaints from the F5D Pylon Racers, mostly about the busy background sights if you flew low, and the Timing & Scoring crew was not really up to snuff until about 1/3 way through the championships.


Steve Landing


Steve making sure the plane was in the circle–dork!


The airfield has two very large hangers for their club planes and a very nice café at the field end of the hanger row so you can watch the tugs tow the gliders up & out to the nearby mountains to start their day of soaring among the mountains & valleys of central Austria.


The entire event was sponsored by Red Bull, so as you can imagine it was a very lavish production from the oversized and well equipped competitors’ tents to the Free Welcome Banquet and most impressive closing ceremony any of us had seen, ever!


Both days were overcast with some showers & colder than the previous week which had been sunny & warm for our practice. We had this before in Kiev, Ukraine where the practice was sunny & hot with sun screen being used liberally, only to have the competition be in cold, rainy & windy weather! Oh well such is flying by the calendar vs. flying by the actual weather!


Of the four rounds planned, only two were run due to the weather, with most scores improving markedly on Friday. Results of the Turnau Cup were, Lenny 17th, Steve Neu 25th, Jeff 36th & Patrick 44th (2nd Junior!)


Party Time


Party Time


*Sat. they had the Opening Ceremony in the Big Tent as it was raining all night. A very large Brass Band of traditionally clad musicians in Lederhosen, performed traditional Austrian Alps music while we were served beer & wine before a buffet of Austrian foods, the table had to have been over 25 feet long! Many Thanks to Red Bull for their sponsorship of the entire event, it was awesome.


*Sun. This was the check in and registration of the models & batteries. Today’s Gremlin was that ALL of the Watt/Min. limiters failed! Jeff & Steve soon figured out the problem & back at the Hotel they did some re-wiring and when checked a second time all were within specs.


After the “Official Practice” where the field with the Timing & Scoring personnel to be used in the Worlds is given to each team for 20 minutes of uninterrupted practice, “Sparky” Patrick managed to short his battery while taking it out of the plane. No tissue was damaged in the Big Flash” but both connectors needed replacing!


*Mon. Jeff Keesaman was the “Lucky” #1 in the flight order, and managed a respectable 46 legs for 27th out of 46 competitors, the best were 4 score of 50 legs. Patrick did 45 legs to take the lead in the Juniors until Bastin Mlineric beat him by 2.5 points!


*Tue. I went sightseeing in Vienna, opulent palaces and the Belvedere has a stunning collection of art from Andy Warhol to Van Goth’s last painting to a collection of medieval art. Unfortunately the Belvedere itself was closed for remodeling.


Back at Turnau, Lenny’s gremlins returned! His backup model had a wing bolt embedded nut come loose, so it couldn’t be flown. When he turned on his ‘A’ model and aileron servo was dead, so he taped the aileron in neutral. It flew a little squirrely, but he managed to make 44 legs in his flight.


Patrick’s competition in the Junior Division, Bastion from France, actually pulled ahead of his seniors team mates so Patrick was now well behind him. The rest of the Team USA posted good to average scores, but not good enough to make the top ten.


*Wed; Early in the 2nd round a big gust of wind, 50-60 mph, struck the flight line and tents, literally blowing the sides out of the Australians tent and slightly damaging one model. The judge’s tent was also blown out and some equipment was knocked over. The afternoon round was cancelled.


For my sightseeing that day I went to Salzburg and visited the Mozart House and found it very original and packed with great Mozart displays including two of his original pianos. On the way to Vienna I tried to stop at the Beethoven House, but it was closed for remodeling.


*Thur; The day started bright, and sunny with only a few scattered clouds, in contrast to the weather since Monday which was always cloudy with periods of rain from sprinkles to heavy cloudbursts with periodic wind to lower the chill factor to 40 or so.


At the end of Wed. the top ten spots were Italy, Austria, and Germany with Steve Neu the top of Team USA at 18th.Thursday scores were all in the 44-46legs range, with Steve doing 48, and Patrick doing 47, his personal best!, everyone making good Thermal Duration times and 30 point landing as the norm. As it was all week, the Base A & B judges were either early or late in their button pushing signals to the pilots, not the type of precision expected from Austrians!


Fri: Bright sunny & warm! This was the makeup round for the one lost Wednesday afternoon. Lenny got a 47 leg run and finally shook his gremlins! Patrick did 45, Jeff 45, Steve 47. When the Contest Results were posted the Team USA results were;


Steve Neu                   17th

Lenny Kerr                  29th

Jeff Keesaman             31st

Patrick Liddy                32nd, 2nd Junior


There were a total of 46 pilots.


Team results were;

Germany                      1st

Italy                             2nd

Switzerland                   3rd

USA                              7th


It is interesting to note that the top two pilots were only 2.6 points apart out of 6,962.8 points!


Team Germany


Team Germany enjoying the sun


On the way back to Zurich to get our flights home, we detoured to see the picturesque Mad Ludwig Castle that was the inspiration for Disneyland’s Sleeping Beauty Castle. It looks like it came right out of the 14th century with tall spires and turrets all around..


On the way in we had stopped at Ludwig II’s most famous castle, a reproduction of Louis IV of France’s Castle at Versailles. The castle is on a private island in the middle of a lake, and is known as the Chimsee Castle. Its construction and decoration nearly bankrupted the ruling family at the time and was never finished, only the main halls and bedrooms were completed. It’s interesting to note that Ludwig only spent a total of less than a month living there; his longest stay was 10 days in the year before he died at the age of 43 of drowning in a boating accident that was never really explained.


Although the flight over was on-time & very pleasant, the trip home was right out of ‘Planes, Trains and Automobiles’. Even though we left our Guesthouse early in the morning, the freeway was backed up for many miles because of a large accident. Jeff used his iPhone to come up with a way to get around the freeways using secondary roads, but Jeff & Shania were the only ones to make the scheduled flight. Steve was held up at Security while they poked through his batteries so he joined me on the next flight to Chicago. While we were waiting, I found a 50 Euro note on the floor ($70)! So I went back and had a shopping spree at the Duty Free store before we left.


When we got to Chicago to change to United for the trip to San Diego, the lines for Passport Control, Customs, and Security were so long that we both missed our connections and had to wait another 2 hours to catch our final flight. We finally got in after 11pm vs. the 8pm we were scheduled to arrive home. Boy is the San Diego Airport lonely at that time of night!


No one has made a bid for the 2016 Championships yet, but we bugged Japan to sponsor the event in Hawaii! Who wants to go?



More pictures:




Austrian pilot and helpers during final flight





Belgian pilot concentrating on landing



Belgian 2


Belgian pilots and helpers looking a little worried





F5D pilots relaxing after their first flights



F5D Winners


F5D winners



Last day


Last day of contests in the morning–beautiful day!



Keep an eye


Lenny and Steve help keep an eye on Jeff’s plane





Let the sales begin–F5D models for sale after the contest



Swiss party


Party time–some Swiss friends





Team Australia after last flights



Australia 2


Team Australia making some last minute adjustments before heading to the flight line



Tim and Bruce


Tim Lampe and Bruce Brown–USA F5D working on models





Unique Danish methon to heat cure epoxy





Was it the nose that had to be in the circle?





Early morning on the flight line

Multiplex Gemini(s) After Two Tries Let’s Get the (Final) Pair Really Right


For most RC pilots a hundred flights on one of these simple foam airframes,  when flown off of something recognizable as a runway,  seems like a reasonable  expectation.  The build-up will be directed to that goal,  even though we expect more out of ours.  Even landing them on long grass as a crop instead of compressed sand.  A Gemini could be an aerobatics trainer,  although your first experience with ailerons and “full house” (zu Deutsch nicht volles Haus,  sondern ein USA RC Fliegerausdruck for Alle drei Flugaxen plus Motor gesteuert) ought to be already in grip.


But when we just wanted to fly relaxed and enjoy an outside experience,  despite of,  or maybe because of,  a cumulative thirty other flying things between the two of us,  the Multiplex Gemini was a favorite.  Compared to our F3A (all out precision aerobatics  see VisionAir) and 4D (flat plate things with huge control surfaces,  see Park Master or DW Airplanes) types:  Knife edge flight (only level,  no loops),  aileron rolls may be axial or not depending on speed and asymmetrical upright/inverted flight are the weaknesses,  and the strength.  The Gemini is a stable platform able to buck some wind and it doesn’t require constant/absolute attention required when remote piloting “pattern” and really agile stuff.  


Real Flight (5.5) doesn’t have anything really comparable,  the closest might be the virtual Park Master.


If you want to “stunt” some,  have ordinary flying skills and want to fly carefree,  the Gemini was a great choice.  Was as they are being phased out!  But ours would never have made it that many flights without some select reinforcement,  and only hitting the ground when intended.


Much of the journey isn’t airframe specific,  I keep my notes in this form as the procedure is entertaining.  The Editor and I go clear back to my brain damaged four years of life,  back when most people didn’t believe in electric powered RC flight,  now a decade and a half mostly recovered from,  he enjoys his role as publisher.


So,  here in condensed form is our experience,  flight and build logs,  compressed down to what functioned best,  with some things to avoided too.  It was,  and is,  an Radio Controlled flying adventure.  And not just made three flights and everything is great of most reports.  We had twenty different versions of propulsion and four kinds of servos along the way.  As in doesn’t anybody else ever sit there frustrated with things that don’t go right on the first try,  or on flight (380) accidently discover a combination,  just slightly different then the twenty previous ones,  which is great?  We fiddled with and fly our stuff until they are really right.


About a Stock Gemini
If we exclude the transmitter,  receiver and the other stuff required for general RC flight (such as the battery charger),  from the economics,  figure the cost of a new Gemini with all new parts and three batteries was in the four hundred to six hundred dollar range.  As always,  if you don’t have a clue,  just follow Multiplexes recommendations.  Propulsion wise in the USA that means the “Tuning” i.e. heavy (135) gram motor.  The original was an (80) gram motor,  still available for the Park Master.  Which papers out to around five bucks a flight for a hundred flights.  To keep that in perspective,  at three flights a session that’s nine months of once a week flying.  If you have an inbuilt Gemini kit please let the Editor know as I’ll buy it off of ya,  can’t get them new anymore.


If you had assembled a foam airplane lately,  and all your electrical and radio stuff worked correctly on the first try,  figure about six to eight hours to assemble a Gemini.  Add another hour to tape the leading edges and another hour or two to iron on the excellent decals they come with.  But why hurry?  Unlike an ARF,  you get to chose the components and there is still some satisfaction to having had a hand in assembling what you fly.  That choosing the components is something edited out by the censorship of omitting experience beyond just making three flights.  I’ve seen published reports where all they made was one flight!  We made (450) flights and assembled four airframes for this report…


Of all the Multiplex lineup the Gemini is the easiest to glue together straight.  Who’d have thought of that as biplanes are usually a real expletative deleted to get the wings aligned with each other and the rest of the airframe.


The single most important assembling a Gemini step,  omitted with staggering frequency,  is to take five minutes sanding the leading edge of the wings smooth.  Use grit in the (320) to (220) range (i.e. fine,  about what you would sand car paint with),  watch it as the foam of the wings is soft,  which helped keep the weight and cost down.  While you are at it the trailing edge of the wings also often have a slight lip,  which screws up airflow all out of proportion to your expectations.  It takes a pleasant hour with a sanding block,  the best quality packing tape and a covering iron to make the wings leading edges last a long time.  Without some hardening the leading edges quickly abrade away,  it still flies,  but not near as well.


Me,  I enjoy working everything over for an hour or so sanding.  That makes applying my usual tape (leading edges and hinges) and fiberglass easier.  It helps with the decals and any paint too.  I’ve done more packing crate (foam and tape) airplanes then the Harbor Soaring Society allows (our manufacturer of the world’s best electric RC motors has been open about his disapproval too),  it takes me an hour to tape the leading edges and hinges of a Gemini.  Even at that about one strip in five of tape I have to remove and re-do.  Use a covering iron takes out the wrinkles,  more important,  the heated tape binds much better then cold pressed.


I don’t know what the difference really is between the Elapor specific CA (glue)  and the many other fine CAs out there,  but I preferentially use the Multiplex glue.  Even if it costs a couple of bucks more,  somehow Elapor goes together with it better.  CA is the only glue I use on Multiplex airframes.


The basic servos are either Multiplex Nano(s) or HiTec HS-55s (plus cable extensions not required for the Multiplex servos in the Gemini,  which might swing the economics in their favor,  the Multiplex quality control may be better too) in the eight gram size,  which may be expected to outlast the airframe and give satisfactory performance.  The HiTec HS-65s (costs about twice as much per servo) heavier at twelve grams (identical external dimensions) with their better precision and stronger,  more durable gear trains are worth every bit of their additional price.


From Mini-Mag experience somewhere out beyond (300) flights the gear trains of HS-55s,  and possibly the electronics inside (that’s a mechanical potentiometer in them),  wears out.  We haven’t even approached the limits on HS-65s.  Wreak an Elapor airframe,  cut the servos out,  scrape off the glue and foam,  and use them in the next airplane.  I’ve had the twice as big HS-82s last through three Twin Star IIs for (600) flights.  If you have them,  the twice as big ((18) grams verses (8)) servos fit in just fine with just trimming the foam a little.


However, if you misunderstood that the little aluminum connectors for the wires from the servos to the control horns must be both snug and still turn,  things don’t do well.  Even locked on hard,  so the wires have to bend,  things go sort of ok for a while,  until the servos quit.  Don’t forget to CA glue the little brass nuts on.  If,   with the parts in your hands,  that didn’t make immediate sense,    get yourself some help!  Those little bitty parts are essential,  and prone to rolling off somewhere,  try assembling over a towel.


It is exquisitely easy to change the propulsion of (almost) all Multiplex airplanes.  Two screws hold the motor mount plate on,  the motor is hung off the back,  changing stuff can’t be any easier.  That handing the motor off the front to a plate along with impact resisting foam makes for durability the likes of which we didn’t even dream of not long ago.  The modern aluminum motor mounts are fine,  the plastic ones warp.  It depends,  the “frame rails” in form from the hard plastic inserts glued into the fuselage sides may not hold up all that well either,  those four screws for adjusting motor angle (down and to the right) dig into them.  


Motor Mount


Out around flight (160) I sanded the nose of Gemini 2 flat and fiberglassed on a wedge of plywood.  By which I adjusted the down thrust until it was about right.  About right as in on application of full power it first pulls forward and down (figure with a (135) gram motor in thirty feet forward about two foot down),  then it angles up a little up.  With the wings two different sizes and the motor in between there is no perfect angle with the Gemini airframe,  and it will vary depending on the motor and propeller.  If you are inclined to flying a Gemini slow,  aileron rolls at low speed are corkscrews,  fly a little faster and they straighten right out.  That’s most pronounced with a heavy motor,  ten or eleven inch prop with the pitch half the diameter (10X6,  11X6).  See above,  the Gemini isn’t a precision pattern airplane.


If you fly the lower ailerons stock (as in just glue the control horns on with CA) the control horns stay on (no problem with the rudder or elevator horns tearing out either,  unlike the Twin Star II),  but the aileron foam between the control horn (to which the servo is attached) bends between it and the link to the upper aileron as we observed on Gemini 1.  Gemini 2 the lower ailerons were fiberglassed the inboard three inches,  it was the top ailerons which developed a bend at the control rod attachment.  These wonderfully simple to assemble foam things have just slight differences in foam density which accounts for things like that.  


I like my flight axis balanced,  two aileron pairs were too quick relative to the elevator for me,  even with minimal throws,   so out around flight (170) I disconnected the upper ailerons and flew on with just the lower ones,  which,  by a test flight,  did not suite the other pilot.  I have a fluid,  energy efficient style (left over from when electric powered RC airplanes barely flew) the reduction in drag (those bare wires have almost as much resistance to airflow as the foam struts between the wings) makes for a better glide and low powered phases.  The other pilot alternates between airplanes,  tendency F3A (precision dynamic aerobatics) and getting faster airframes all the time.  He has now reached the state of proficiency where he needs to enter some competitions,  to get encouragement from other demanding RC pilots.


I like a simple,  if garish,  paint scheme.  Minimal paint as paint can weigh a whole lot more than most pilots recognize.  The other pilot liked both the decals which come with the Gemini,  and some additional contrasting color paint.  If fresh,  the decals (very easy to apply) press right on.  As a veteran of iron on plastic covering (and old enough to remember the hassle of shrinking paint (i.e. dope) over paper or silk) I iron on my Multiplex decals.  Ironed on the decals will outlast the airframe.  They may even have some structural value.  


That contrast (between top and bottom,  and in my case front and rear too) is more important to a Gemini then most,  we can’t see them well,  and with it ability to decide orientation,  on them out beyond a hundred yards.  When you do paint Elapor keep in mind if you use glossy paint (verses flat) that suddenly the intersections between the foam cells,  plus the inevitable uneven surface of expanded in the molds foam,  shows right up.  Then go for it.  I use spray paint in the ten dollars a can quality,  the available Elapor primer then isn’t needed.  


The Gemini is a nice looking RC airplane,  you want a spiffy looking RC airplane,  get an ARF,  and tell me about repairing it.


Over time all plastics,  rubber and any non-metallic material with some stretch and compression properties (such as EPP and Elapor foams) goes hard and brittle.  A reasonable expectation for the Gemini is around five years to eight years after production (at San Diego temperatures,  i.e. perfect),  if you fly it or not.  There’s another issue,  the wire inside the plastic sleeves rusts,  binding things.   


Additional lessons from Geminis 1 and 2,
for longer life airframes as we did to Geminis 3 and 4.  


Without taping the leading edges (after first cleaning up the casting flash from the mounding process) we’d have been ready to junk these things,  or at least replace the lower wing,  after thirty flights.  


Since ours “bonked” (zu Deutsch,  etwa ein leichter Stoss die einem Klang,  als ob man auf einem Rohr geschlagen hat,  erzeugt.  eindeutig Amerikanisch) the nose on every single landing,  gluing on the lower wing (and while you’re at it the upper one too) reduces the tendency of the fuselage to bend up right at the intersection of the nose to the lower wing.  Gemini 1 also developed a bend at the rear of the lower wing,  levered down from the fuselage bending away at the attachment bolt.  We figured,  might as well glue the wings on as the assembled Gemini easily fits on the back seat for the drive to the flying place.  For Gemini 3 and 4 the internal wing mount foam and plastic mounts (the part the screws go into) were cut out and the entire “tunnel” fiberglassed.  That not only stiffens and (less important strengthened) the fuselage up some,  it also allows positioning the battery further reward too.


Battery Placement


We like the (35) mm diameter size motors in our Geminis.  If you stick with the HiMax (80) gram motor at (30)mm or similar,  the wires from outrunner motors have enough room to get past without dragging on the rotating case.  When you go to the (35) mm size,  we ground out a trough in the nose for clearance.   There was enough fiberglass to make up for any loss in strength anyway.  As an alternate run the motor wires forward and then back through the chin duct.


Gemini 1 all the fiberglass was held on with water base hardwood flooring paint,  it was good enough,  and a whole lot easier to work with then two part fiberglass resin(s).  Gemini 2,  3 and 4 were mostly done with two component resin,  at least there were strength and rigidity was a major factor.  But waiting for it to harden is a bore,  for the finish coats I used water based hardwood flooring paint,  which may be sanded to a decent finish and seals the foam from my greasy fingers.  A final layer of (4) ounce per square yard fiberglass (as light as it gets) went over the fuselage from just rearward of the cowl forward and the whole underside of the lower wing.


It took six applications of epoxy on fiberglass,  wait,  and sand to finish each of Geminis 3 and 4,  at two hours a cycle,  with the final coat being fiberglass held on with the much easier to sand (water based) hardwood flooring paint.  Which added about twenty bucks to the price,  of which the most expensive component was sandpaper,  which also took up the most time.  Why so many cycles?  Many of what to be hardened/strengthened was compound curves,  which require really thing fiberglass cloth and you can only do a limited amount at a time.  


If I were asked to assemble another Gemini for an average pilot,  landing on more reasonable runways then we do (and not much wind,  i.e. Mission Bay) with (experienced based) expectations of more like fifty to a hundred flights (before a crash sets the statistical limit on the airframe) I’d likely do just two fiberglass cycles.  And then only on request.  But I’d refuse to touch a foam airplane unless the person commissioning the work agreed to taping the leading edges and lower wing tips.


Speaking of commissions;  For a while I had a well made (and expensive) carbon fiber motor plate,  interchangeable between most Multiplex airframes,  which,  uniquely,  included most of the needed down thrust built in.  Mine seemed to have turned into that warping white plastic overnight while I spent the night at the flying field in my camper.  I woke up that morning way late,  alone,  my head hurt,  my feet stank and at first I couldn’t focus.  When the fog inside lifted I wondered how six bottles of good quality local wine wound up on the floor,  two of them empty.  Well,  the flying field is on a hill surrounded by vineyards with a nice view of the Rhine and far back enough to be a quiet place to spend the night as the lights of the villages across the river come on when it’s too dark to see to fly.  A year later the motor plates were unavailable.


However,  while the two component fiberglass epoxy stuff in Germany has very low viscosity,  and at (45) minutes longer pot life then the twenty minutes for what Hobby People sells in California (pot life,  i.e. the time you can paint the stuff on after mixing,  keep going at your own peril as it won’t be as strong and takes days to harden up),  the German stuff (good enough for building small airplanes the pilot can sit in) is an expletative deleted to sand.  The USA stuff,  while higher viscosity (makes following compound curves harder) can be easily sanded to even feather edged.  But probably the most important difference is that at room temperatures (warmer then my basement workshop) the German stuff needs at least twenty to thirty hours to harden up,  the American stuff four to six.  Next trip Wiesbaden/San Diego/ Wiesbaden I’m bringing the USA resin back for myself and the other club members.  Both start out opaque (not quite transparent),  the USA stuff quickly yellows,  the German stuff shrinks.  


Taking off on the landing gear from a hard surface,  and the scale like “this is a model of a real airplane” (although there is no man carrying exact match) even after we went to folding propellers in the ten inch range,  requires down elevator for the first few yards,  then let it go neutral and the Gemini will rise off ground just fine.  However,  it is prone to prop strikes on takeoff,  initially half the price of the kits went into propellers.  It took a few tries to decide on the right,  for us,  prop size(s).


That from Multiplex wire landing gear is only just good enough even flying off of a hard runway.  Expect to have to hand straighten the main landing gear often (not necessarily a bad thing,  that springiness protects the rest of the airplane) and that the wire holding the rear wheel isn’t all that durable.  The Gemini is a great flier,  at a nominal purchase price,  so if you have to add a better landing gear,  it’s still a great flier and inexpensive.  We used the landing gear as an “arrestor hook” over the long grass we have to land on,  at which the stock mounting plate tore out at twenty flights.  The long term solution was removal of the hard plastic stock wire mount for a replacement carbon fiber landing gear fiberglassed on.  While you are at it,  bigger diameter wheels make for taxing easier.  A simplest solution for the too weak main landing gear is to bend up an additional wire and tape it to the original.


That simple wire for the rear tail wheel won’t last all that long.  Back when digital airborne movie cameras were new and novel (about fifteen to twelve years ago),  one SEFSD pilot mounted one facing rearward on a Telemaster,  we were surprised how much impact that little rear wheel takes.   From a recent conversion of nearly identical Fun Cub to a more durable rear wheel assembly figure twenty bucks for materials and two or three hours of modeling,  worth it,  but not until the original gives out.  Gemini or Fun Cub,  when running a (135) gram motor you need some additional weight back there anyway,  if you didn’t clearance inside the fuselage to move the battery further rearwards then Multiplex intended for the original (80) gram motor setup.  


The nose had to be beefed up as Gemini I landings were;  First hung the main landing gear up in the grass,  then bonk the nose down every single landing.  We always giggled about that as RC airplanes aren’t expected to withstand that,  and it looks,  after elegant flying,  amusingly clumsy.  Gemini II the lower wings leading edge,  the chin air inlet,  the nose,  and the servo arms hanging down took the landing skid.  Gemini I did rather well with (4) ounce per square yard fiberglass cloth (figure six layers) held on with hardwood flooring paint.  Gemini 2 had the same in fiberglass.  Geminis 3 and 4 were treated inside at the servo/air outlet areas and again at the outside there as if the lower wing snags on landing that’s where the fuselage breaks.




We like folding propellers,  easily available in Germany,  for which the nose of all four of our Gemini’s were cut back a bit to let them fold.  Only at the bottom,  it’s the “chin” which takes the most landing hits,  are the blades expected to really fold flat.  If at the sides and top the blades only fold to forty five degrees the slight reduction (at Gemini glide speeds ) doesn’t justify the large increase in modeling to get them to fold flatter.  These aren’t F5D airplanes!  The Elapor block,  cut from the wing mounts when the inside was “tunneled” was used to block off the useless air inlet.  Six multiple coats over that part of the nose and two over the black of the block.  Taper the layers as you don’t want an abrupt change in rigidity as that creates a breaking place.  The trick is to balance the “bash plate” nose to transition into the flexible Elapor,  I can’t set it to words.  Even if the Editor or I,  both educated as engineers,  could put numbers to it (it would take finite element analysis,  beyond a basic undergraduate degree,  and detailed knowledge of the foam layout),  even most engineers couldn’t read it…  Try spacing the ends of the fiberglass three quarters of an inch (two centimeter) short of each other.


Although even just glued on the control horns don’t tear out,  in particular at the ailerons the foam where it has to actuate the upper aileron develops a warp.  I fiberglassed the inboard three inches of the lower ailerons (the one with the servos) of ours.


That chin air inlet is a relic of a while back,  it no longer serves any purpose.  Unless you consider collecting grass,  mud and,  where we land,  horse droppings,  useful.  Mole hills are the usual cause.  With the electrical stuff of the last five years,  according to our fingers all that get more then warm is the motors.  Motor controllers and batteries don’t heat up the way they did even a few years ago.


The rudder doesn’t get much use in a Gemini,  if you can’t afford everything you like,  a less expensive servo (with it’s hunt for center response,  sloppier gear train and shorter service life) there might be fine.  I had an a Nano Karbonite (HS-65) in Gemini 2’s rudder,  which was cut out and installed in Gemini 4.  Since I wanted to keep flying Gemini 2,  the replacement was a physically larger Hobby People House Brand servo ((16) grams,  $11- as of 2014),  which did fine.  The bigger external size took up the foam lost cutting out the smaller servo,  the was just enough foam left.


There is an abrupt change of rigidity of the lower wing right at the servos (only the upper wing has a spar)  to length the service life (12) ounce per square yard four inch diameter circles of fiberglass were applied top and bottom.  Gemini1,  where the lower wing seldom touched the ground that wasn’t necessary.  Gemini 2,  where one wing tore off and the each side of the fuselage split right at the fuselage servos,  it was.   Geminis 3 and 4 the whole bottom of the lower wing was treated with a layer of (4) ounce per square yard fiberglass over the whole wing with three additional layers over the middle extending to the fuselage in front of and behind the lower wing with a four inch patch of fiberglass over the top too.  


Other then taping the leading edge the top wing doesn’t seem to need any improvements at all.  Oh it gets some scrapes from transport (soft and light foam ya know) but other than that time I just hit a branch the upper wings did just fine.  If you go back to the first SESFD Gemini report of mine I substituted a carbon spar for the stock fiberglass one to save (15) grams.  In between,  although fifteen grams does make some difference,  it wasn’t enough to justify riding my bicycle to one of the few remaining hobby shops (my high roof camper wouldn’t fit in any parking structure) and then taking the bus back up the steep hill (two hours round trip plus three dollars for the bus) at the moment I was ready to start building.


It’s not enough that the horizontal foam of the wing struts is glued,  you have to flex the wigs and get some glue in all the way around too.  Geminis 3 and 4 contact cement was used for the flat,  then the wings bend and CA flown in.


There just wasn’t much to be done to improve the wings,  upper and lower,  out past the wing struts.  Make one of these inherently flexible foam airframes too strong and rigid and they weight too much.  With that neat scale top surface,  that looks just about like fabric over the ribs of a “real” one,  things like inletting carbon fiber rods or strips were rejected.  I figure an additional fifteen hours over minimal assembly as reasonable for the Gemini,  when its used up,  assemble another something.  If you need a more precise airframe,  get a different airplane.  Want something spiffy,  get something else.


I’ve got to admit it though,  I really enjoyed the better controllability at the elevator of quality servos and wished I had them in the wings too.  But,  being almost,  but not quite,  completely broke at the end of every month…


The pair of unbuilt Gemini kits we found in E-Bay late 2014 were complete and in fine shape,  except that the glue of the decals had aged.  The first attempt to apply them with a covering iron resulted in a mess of little swollen pustules,  almost all of them in the gray coloring or the clear portions.  After which they were applied by hand,  just touching down and then pulling them back up until things aligned well and then gone over with a standard hair dryer,  pressing down with a soft cloth.  As part of making Gemini 1,  after three years of service,  re-fit for a few more flights,  those details applied new were holding on rather well,  


Things are looking up,  they are finally building more in Germany,  and maybe I can get life in San Diego going again.


Reasonable Quality doesn’t Overheat
One reason I take the time to put this down in print;  If you find your stuff overheating,  and you didn’t block off the front and rear air flow,  the problem is your equipment.  


Quit buying cheap stuff!  You may use the price of HiMax motors (standard for Multiplex until recently) or the Multiplex house brand Permax as a reference for the minimum to spend on motors and controllers.  Use HiTec and Multiplex as the standard for servos too.  


Repeatedly when following Internet Forum threads the problems are using servos and motors that barely function,  and often not even that.  That may partly be attributed to the censorship by omission of motor efficiencies in a vast majority of reports,  lack of commentary on imprecise servos which don’t fail during the first five flights (they didn’t even try to compare different ones!),  or even mention that the servos need to be individually centered to their control surface(s) and a general lack of reporting on the tuning as an adventure to getting your stuff to really fly right.  


The other pilots new Gemini 3 was fitted with four HS-65s,  bought new from current production,  of which only two were centered to each other as a reversed pair (for the ailerons) and none them of which were at right angles to the case.  The Multiplex Brand servos have been better in that respect,  as is generally the case as the price of the servo increases.  That’s weird,  pay more,  and get better performing stuff.  If you want the airplane to fly really right,  any airplane,  you need a computer radio to individually center the servos for equal throws at the control surfaces,  or the patience and luck to at least get the aileron servos to match each other.  At least with the SESFD we have competition pilots setting a good example,  who,  if asked,  will be glad to clue you in.


I was staunchly old school in not taking full advantage of the improvements in transmitters until a semi-pro sponsored pilot asked if he could fly my airplane.  His first comment was how did I fly so well without using exponential,  although he is the better pilot.  What we need is for small stick movements about where the control sticks are centered to give small control surface changes of angle,  with increasing large movements as we go to the extremes.  Due to mechanical geometry,  that bit about proporti

2015 Freeze Fly

Those hearty soles who braved the harsh San Diego winter to come out and show Mother Nature that even frigid 65 degree weather cannot keep them from flying.


Freeze Fly 2105



Pictures from the 2014 Holiday Banquet


Thanks to Tim Attawy for arranging the use of his church’s beautiful banquest room.  The food was great and so was the BBQ.  Click the pic for more pics.