Conference vmszoo::rc

        See note 387, there's a lot of discussion about electrics.
    Your project will be a good case study for those of us who have
    some interest in electrics.  From what I've been able to gather
    about electrics the advice would be to build it as light as
    you possibly can and don't skimp on bucks for battery and motor.

    Good luck, let us know how you progress.
    
    Bill
    

    A guy showed up at the Acton (Mass.) field a couple times this summer
    with his newly built Electric Cub. I helped him hand launch it twice,
    but it didn't stay up long. It felt kind of heavy to me, and we
    both came to the conclusion that it was underpowered. He later tried
    7 cells instead of 6, but told me it still wasn't enough. So I agree
    with the previous reply, build it light and don't skimp on power.
    
    By the way, I saw the same guy at the field a little while back
    with another electric, and this one FLEW. I don't know what type
    plane it was, but it was clearly designed for aerobatics, and he
    had it doing loops and rolls for a good 8 minutes on one charge.
    
    

    The Great Planes Electric Cub comes with the motor,but no batteries.
    I'd be interested in knowing if his motor was the one that comes
    with the kit.
    -ph

    I built my electicub with an astro cobalt 05, it is my third (or
    maybe fourth) electric.  #1 was an electra.  I recommend this as
    a better introduction to electric than the cub.  one of the worst
    features of electric planes is their ability to survive IMPACT,
    or maybe i should say lack of feature.  because the CUB is a smaller
    plane, it will fly hotter than the electra.  odds are, if you haven't
    flown in a while, and you start with the CUB, you will just wreck
    it trying to get it up, down, or turned a low altitude.  the electra
    is a much more docile flyer.   the cubs stock motor is a MB550,
    the same as those found in most electrics of > 4ft wingspan, that
    include their own motors.  I highly reccomend buying an 035 or 05
    cobalt (although they are expensive).  the 035 cobalt has as much
    power as your 550, but is much lighter, turns higher RPM, and can
    be flown with 900 MAH batteries for an overall improvment in flight
    characteristics.
    

>    I have a couple of spare 550mah Rx packs, and either 3 or 4 S-28
>    Futaba servos that I'm looking to trade for a 225mah Rx pack, and
>    a pair of S-33 micro servos. Any interest out there??
    

    sounds like the lament of the rare electircus-flyerus bird,
    looking to trim a few extra ounces from an already "spare"
    carcass.

    If you really want light weight, try the micro receiver from
    tower, with the TSS-10 servos and a 50MAH pack, total system
    weight is something less than 5 Oz.  Fully compatible with a 4NL
    transmitter, and less than $70.00.  you get 2 flights per charge
    of the reciever battery, but you can fast charge it at the field
    with a peak detecting charger.

    I could use some advice from some electric flyers out there.....I
    expect to start building a PT Electric this weekend...I'm an
    experienced builder/flyer so there's no problem there)I hope)...What
    I need info on is the motor/battery combo that I should use.  Although
    I've
    read every note in this file about electric((that's why I bought
    a PT-electric).  My problem is this.  I purchased a couple of 7.2
    Volt 1200mah batteries with the kit.  Now I'm leaning towards using
    an Astro cobalt motor.  The Astro literature recommends 8.4v 7 cell
    packs.  Will I get the legendary astro cobalt performance with 6
    cell packs??.  Should I buy an Astro 035 and use 6 cells or go all
    the way and get the Astro 05/geared and new 8.4 V 7 cell batteries??
    
    					comments anyone?
    
    					regards
    						Bob

RE: < Note 408.5 by 3D::COLLINS >

    I've never used an Astro cobalt 035 but I would guess that it would
    be a fine motor for the PT-Electric when used with a 6 cell pack. 
    (Maybe Randy Cohen has some input here???)

    I would NOT recommend running an Astro Cobalt 05 on 6 cells.  If you
    choose the 05, get the 7 cell pack(s).  Performance of an 05 with
    only 6 cells will be marginal at best (and probably it won't fly at
    all).

    With the PT-Electric, you could also consider the Astro Cobalt 05
    Direct drive, although the 05 geared with a folding prop is probably
    a better bet.

                       _____
                      |     \
                      |      \                          Silent POWER!
      _        ___________    _________   |            Happy Landings!
     | \      |           |  |         |  |
     |--------|-  SANYO  + ]-|  ASTRO  |--|              - Dan Miner
     |_/      |___________|  |_________|  |
                      |       /           |     " The Earth needs more OZONE,
                      |      /                       not Caster Oil!! "    
                      |_____/

>    I've never used an Astro cobalt 035 but I would guess that it would
>    be a fine motor for the PT-Electric when used with a 6 cell pack. 
>    (Maybe Randy Cohen has some input here???)

    Never used one, but from the standpoint of power output, the 035 Cobalt
    has about as much power as the 05 tin can motor the PT-E comes with.
    Direct drive with a 7-4 or 7-5 should work ok.
    
>    I would NOT recommend running an Astro Cobalt 05 on 6 cells.  If you
>    choose the 05, get the 7 cell pack(s).  Performance of an 05 with
>    only 6 cells will be marginal at best (and probably it won't fly at
>    all).

    Disagree.  05 Cobalt on 6 cells with a 3:1 gear would probably turn a
    10-6 at 5000+ RPM, more than enough to fly the plane well.  Of course, 7
    cell would work better.  But, if you have two or more 6 cell packs, you
    could buy a 15 Cobalt, run the packs in series, and have a *REAL* good
    flyer.  (I have a modified Electra, some of you have seen it.  10 inch
    longer wing and a V tail.  It flies with a Kyosho 240 LeMans motor, on a
    3:1 gear drive, turning a 12-8 Master Airscrew folder, and a 6 cell
    pack.  Climbs out really well, even though the prop is olny turning at
    about 4500 RPM).

>    With the PT-Electric, you could also consider the Astro Cobalt 05
>    Direct drive, although the 05 geared with a folding prop is probably
>    a better bet.

    My ElectriCub flies on a 05 Cobalt direct drive, 6 cells and a 7-6
    Topflight prop.  I think it flies just fine.  Climb out is enough to get
    it high enough that I can glide it around for quite some time.  It'll
    loop, with a little down, and I've yet to have it even come close to
    stalling on launch.  I'de say it's a good combo.
    

    What you really ought to do is this.  Be sure that when you build the
    plane, the battery compartment is centered under the CG.  You might have
    to modify it a little, but that shouldn't be a problem for you.  This
    gives you the ability to test glide the plane without the extra weight
    of the pack, if you want.  Be sure to make the compartment large enough
    to accomodate a 7 cell pack (it's just about 1/2 inch longer than a 6
    cell pack). then, cut some foam blocks you can wedge in the front and
    back of the compartment, that will allow a 6 cell pack to sit securely
    when the blocks are in place.  Remove the blocks for use with a 7 cell
    pack.  If you don't like the 6 cell performance, buy an extra cell, cut
    up one of the 6 packs, and make it into a 7 pack.  Remove the foam
    blocks, and away you go ! (This is what I did with the modified Electra,
    by the way, and it works great). 

    Well, I'm about to join the ranks of electric flyers.  I am putting
    the finishing touches on my Electrostreak.  I'm using an Astro 05
    cobalt motor with a Jomar SM5 speed control.  I plan to run it on
    a seven cell pack (1250 mAH Magnum from S&R).  I hope to have it
    ready to fly by this weekend.  The only thing I am missing is a
    250 mAH pack for the receiver.
    
    Charlie (Kilo) Watt
    

    Dan & Dan,
    	I'm up for either CMRCM or the Drop Zone.  The only thing I
    may be short on is the flight pack battery.  I ordered one from
    S & R and I also ordered one at Ray's RC.  I can't balance it until
    I get that.  I covered the wing bottom last night so the top is
    the only covering left to do.  I installed my fuse switch but I
    am not sure how I'm going to like that.  I made it out of a couple
    of spade lugs glued into a piece of 1/4 inch balsa.  I cut a slot
    in the fuse and glued the balsa piece on the inside.  I can then
    plug in the fuse from the outside and use it as a switch.  I can't
    promise at this point that it will be ready for Saturday AM but
    I will shoot for then.  Dan, do you think that the Drop Zone field
    is smooth enough for the 'Streak?
    
    Charlie
    

    re.7	Thanks for the info.  You idea of enlarging the battery
    compartment is an excellent one.  Unfortunately, the fuse is completed.
    fortunately, it's not covered.  The mods will be easy and
    straigthforward so I don't expect any problems.  I plan to order
    an Astro Cobalt 05 direct drive system(includes a battery).  Then,
    I'll have 2 6 cell batteries and 1 7 cell battery.  I can modify
    one of the 6 cell batteries if I want more performance.  I don't
    think I'll go for the geared version of the 05 as I have a Thermal
    Charger electric sailplane just waiting for some bench space.  That
    design, with it's pusher prop, has limited prop clearance, so there's
    no use trying to fit a large folder prop on it.
    
    	On to the next question(problem)......
    
    	Here I am with a Futaba 4 ch "attack" radio.  The one with the
    electric speed controller/BEC circuit in the receiver.  The PT electric
    motor has a Kshoyo/tamiya style connector.  The Rx has 2 fat barrel
    connectors.  Since I can't connect the moter to the Rx, I thought
    I should change at least one connector.  That's the problem.  The
    question is...Should I use sermos connectors or just find some
    connector that matches the Rx leads??  I'd like to go first class
    with the wiring and use sermos connectors/jomar 16 ga wire everywhere.
    Where can I get the sermos connectors/jomar wire??  I've tried several
    hobby shops around Marlboro Ma and can't find them??             
    
    	As a progress report on the PT Electric...everythings built.
     Needs covering and radios installed.  The kit is EASY to build.
     Good quality wood, clean die cutting abd simple directions.  With
     2 S-133 servos, integrated speed controller/BEC and some attention to
     weight, It should weigh in at 42 oz with a cobalt 05.
    
    						regards
    			
    						Bob

    re .13,

    Try Future/Active electronics, on Flanders road (I think) in Westboro,
    just a little way off Rt. 9.  They ought to have both 16 Guage (I'de
    recommend something bigger, though, like 14) and *MAYBE* sermos
    connectors.  If not, they should have some sort of good, high current,
    gold plated connector you could use as a Sub.

    
      I am looking for any info that anyone has on the Goldberg Mirage
    550. I have an Electra with stock motor. I had (Crashed, and missing
    in action) an Electricub with stock motor and 7 cell battery.
      I ordered the Mirage on Tuesday to help me get through the Cub's
    loss. I am determined to still give electrics a try, although this
    time I will probably spring for an Astro 05 cobolt w/7 cell. I am
    convinced that if the Cub had additional climb performance, it would
    still be intact and in my possesion (An expensive lesson learned!).
      I like the Mirage because it looks nice, looks to be an easy builder,
    is a taildragger, and seems to have a rugged wing.
      If there is not anybody with Mirage experience, I would be happy
    to report on the plane as I build and fly it,
                            
    
                                             Dan Weier                     
    

RE: < Note 408.18 by WMOIS::DA_WEIER >

    Sorry Dan, but I don't know anything about the Goldberg Mirage 550. 
    However, something else caught my eye:

>      I ordered the Mirage on Tuesday to help me get through the Cub's
>    loss. I am determined to still give electrics a try, although this
>    time I will probably spring for an Astro 05 cobolt w/7 cell. I am
>    convinced that if the Cub had additional climb performance, it would
>    still be intact and in my possesion (An expensive lesson learned!).

    As many long time notes readers will know, I am very fanatical about
    only using Astro Cobalt motors for electrics.  If you'd like to read
    some of my notes on the subject, see notes 
        387.134 - 387.141, 
        387.187 - 387.192,
        387.195

    If that doesn't convince you, do:  Notes> dir/auth=miner 387.*
    and read some of the other notes.

    I believe that "stock" motors are _sometimes_ sufficient for the
    planes that come with them, but 99% of the time, the "stock" motor
    should be thrown away or put into a car or boat.

    Proving that I practice what I preach, I am nearing completion on my
    second Electrostreak (see 387.112-387.117 for notes about my first
    one).  I have set aside the motor that comes with it (may put it in
    a boat someday) and modified the kit to take either an Astro Cobalt
    05 or Astro Cobalt 15.  I plan on flying it with the cobalt 15 to
    start with.  It should really scream.  I'm still hopeful that it
    will go vertical with the cobalt 15, but I can't be sure until I get
    it finished...

    In summary, Electrics _can_ fly well if you are willing to invest
    some money and go for the best.  From the movie "Risky Business" :
    "Astro Cobalts - there is no substitute."  (slightly changed :-)  

                       _____
                      |     \
                      |      \                          Silent POWER!
      _        ___________    _________   |            Happy Landings!
     | \      |           |  |         |  |
     |--------|-  SANYO  + ]-|  ASTRO  |--|              - Dan Miner
     |_/      |___________|  |_________|  |
                      |       /           |     " The Earth needs more OZONE,
                      |      /                       not Caster Oil!! "    
                      |_____/

    Hi Dan,
    
    	I have an electric glider, 72", that I've been flying with a
    stock motor. Performance is marginal at best. I have installed an
    Astro Cobalt motor and will be trying it for the first time tonight.
    Just checking it out in the house, I can tell there's going to be
    a big difference, but I'll post the Cobalt test flight here after
    tonight.
    
    
    Steve

    There was an interesting article in one of the recent mags about
    electric motors. From all the data presented, many (not all) of
    the motors tested were very simular in performance. Any comments
    Dan M. 
    
    
    						Dave
    

RE: < Note 408.21 by TARKIN::HARTWELL "Dave Hartwell" >

    Dave, I'd have to read the article you were refering to before I
    could make an intelligent comment.  Are you referring to the Model
    Aviation article by Bob Kopski a month or two ago?  (For example,
    was it comparing 5 Astro Cobalt 05 motors against each other -OR-
    was it comparing 5 totally different brands/models against each
    other?)  

    However, I will make a statement.  I believe some of the newest
    "stock" motors will deliver nearly the same thrust as the cobalts. 
    However, the cobalts are still worth the money for the following
    reasons:

    1)  The cobalts are much lighter for the same power motor.  The
        "Goldfire" motor that came with my Electrostreak weighs 1/2
        ounce more than my Astro Cobalt 15 and about 1.5 ounces more
        than my Astro Cobalt 05.  In an electric, 1.5 ounces makes a
        *BIG* difference.  Think of it this way: I can throw away the
        Goldfire 05 motor and replace it with the cobalt 15 _AND_ save
        1/2 ounce at the same time.  More power and lighter...

    2)  I'm not sure on this, but I think that the cobalt motors are
        more efficient.  According to the Electrostreak directions, the
        stock Goldfire motor draws about the same current as the Astro
        Cobalt 05.  Thus, the power into the 2 motors is the same.  The
        thing I'm not sure of is if the output power is the same or not. 
        (ie, how efficiently do the 2 motors convert their input power
        to RPM's?)   In other words, assuming the input currents are
        exactly the same, will the Goldfire turn the same prop just as
        fast as the cobalt 05?  I don't know.  I'll try this sometime to
        get some real facts...  I suspect that the RPM's of the stock
        motor will be lower than the cobalt 05.  Every little bit makes
        a difference...

    FYI - there is a very good article on motor timing (brush timing) in
    the July 1989 issue of Model Builder.  In this article, Mitch Poling
    also talks about motor efficiency (as it relates to motor timing).

                       _____
                      |     \
                      |      \                          Silent POWER!
      _        ___________    _________   |            Happy Landings!
     | \      |           |  |         |  |
     |--------|-  SANYO  + ]-|  ASTRO  |--|              - Dan Miner
     |_/      |___________|  |_________|  |
                      |       /           |     " The Earth needs more OZONE,
                      |      /                       not Caster Oil!! "    
                      |_____/

    Most (not all) electric motors of the type were talking about range
    anywhere between 40/60 percent efficiency. The cobalts are 80 percent
    efficient.

    
      Dan,
    
       You already have me convinced that astro cobalt engines are the
    only way to go. I have some questions though, does a cobalt 15 have
    the same exterior dimensions as a 05 cobalt (i.e length, diameter)?
    Besides the magnets that protrude from the side of the cobalt engine,
    are there any other modifications needed for a plane that has a
    stock 05 installed to install the cobalt motors? If the dimensions
    and weights of the two cobalt motors are close it would seem to
    make sense to buy the 15 for the few extra dollare and have the
    ability to use more cells.
      Also, I believe the motor comparison article refered to earlier
    is in RCM (July issue?). It measured both input and output of several
    stock motors as well as the 05 cobalt. As I remember, the Goldfire
    engine registered efficiency very close the the cobalt motor, although
    as you said, the cobalt motor should far out-last the Goldfire in the
    long run.
      I hope to buld a "Streak" this winter, and if my skills are up
    to it, fly it next summer. It really looks like a great plane!.
                                                              
                                      Thanks for the advice,
    
                             Dan (who now has his Electricub back) Weier

RE: < Note 408.24 by WMOIS::DA_WEIER >

    Dan,

        The cobalt 15 is larger in diameter by 1/16 inch.  The length is
    the same.  In fact, the copper colored end pieces are identical,
    it's the black center section that is larger in diameter on the 15.

        On a technical footnote, the black things that stick out the
    sides of the rear of the motor are not magnets.  They are the brush
    holders.  The brushes may be replaced easily.

        No, there are no changes needed to mount a cobalt 05 in place of
    a "stock" 05 as long as you adjust for the size difference.  (Cobalt
    motors are usually smaller than car motors.)  The only thing that
    must be checked is the center of gravity since the cobalt will
    (typically) be lighter.

>    If the dimensions
>    and weights of the two cobalt motors are close it would seem to
>    make sense to buy the 15 for the few extra dollars and have the
>    ability to use more cells.

        Yes and no.  The 15 is designed to run on 12 to 14 cells and the
    05 is designed to run on 7 cells.  If you try to run the 15 on 7
    cells, it won't work too well.  If you can use 800 mAh or 900 mAh
    cells (to reduce weight), then you could switch to 12 cells and
    weigh just 2-3 ounces more than 7 x 1200 mAh cells.  Stated more
    clearly,  A cobalt 15 with 12 x 800 mAh cells weighs only 2-3 ounces
    more than a cobalt 05 with 7 x 1200 mAh cells.  This is what I've
    done with the Electrostreak (actually, I'm using the 900 mAh cells
    that come withe the Astro Cobalt 15 "system".)

        For lots of Astro Cobalt statistics (weight, dimensions, etc.)
    see note 387.213.

        The 'Streak is definitely no where near a beginner's plane as
    you seem to understand.  My first one humbled me _many_ times before
    I finally got the hang of it.  (It tended to crash due to pilot
    error every 5th flight...)  Even after I learned how to handle it, I
    seemed to have a minor (Miner) "mishap" every 10 flights or so.  :-)

        Congratulations on finding the ElectriCub!!  Back in May, I
    ended up swimming half way out in the river to fetch a plane that I
    dunked in there...

        FYI - Electrostreak #2 is almost ready to fly.  I need to cover
    the wing and do a few other "little" things and I'll be ready.  I'm
    going to try to finish tonight so I can test fly it tomorrow and
    then go to the Electric Fun Fly in Conn. on Sunday.

                       _____
                      |     \
                      |      \                          Silent POWER!
      _        ___________    _________   |            Happy Landings!
     | \      |           |  |         |  |
     |--------|-  SANYO  + ]-|  ASTRO  |--|              - Dan Miner
     |_/      |___________|  |_________|  |
                      |       /           |     " The Earth needs more OZONE,
                      |      /                       not Caster Oil!! "    
                      |_____/

    
     Dan M,
    
       Thanks for the info on the cobalt motors. At this point, I think
    I will order a 05 cobalt to start with and stick with the 7-cell
    1200 packs. Maybe the "15" will be appropriate in the future.
    
                                                           Dan W

RE: < Note 408.26 by WMOIS::DA_WEIER >

    I would like to correct something that I said in 408.25.  I made a
    statement implying that a cobalt 15 on 7 cells wouldn't run very
    well.  I was only partially right.  From note 387.214:

>    In talking to Bob [Kopski] and some of the other experienced flyers, the
>    consensus in this area is that an Astro 15 is the place to start.
>    They just use whatever number of cells are required to get acceptable 
>    performance.  They say a 15 with eight cells is supposed to be 
>    equivalent to the 05 with seven cells.  

    I haven't done this myself (15 with 8 cells = 05 with 7 cells) but I
    can imagine these people (Bob Kopski and others) are much more
    experienced in these matters than I am.  I was correct in saying
    that a 15 on 7 cells isn't too good, but adding only 1 more cells
    brings you up to 05 performance.  Not bad.  The only cavet is that
    the 15 weighs 1 ounce more and you have to consider the extra cell
    weight.

    Bottom line is that I have to agree with Bob Kopski.  (I'd be
    foolish to disagree.  :-)  Assuming you can tolerate a little extra
    weight in the specific plane you have in mind, go for the cobalt 15. 
    The only other thing to consider is that most chargers only work up
    to 7 cells.  To charge 8 cells, you will either have to buy a new
    charger or break your 8 cell pack up into two 4 cell packs.

                       _____
                      |     \
                      |      \                          Silent POWER!
      _        ___________    _________   |            Happy Landings!
     | \      |           |  |         |  |
     |--------|-  SANYO  + ]-|  ASTRO  |--|              - Dan Miner
     |_/      |___________|  |_________|  |
                      |       /           |     " The Earth needs more OZONE,
                      |      /                       not Caster Oil!! "    
                      |_____/

    
      Dan M,
    
         I saw the same note regarding the Cobalt 15 on 8 cells. I may
     have to again re-think the choice. Your comment on most chargers
     not being capable of handling 8 cells was an excellent point.
         My Mirage kit has arrived, but in the meantime, I am going to
     upgrade my Electricub with an Astro cobalt. The cub flys very well
     on the stock motor because I was very careful to keep it light,
     but I sure would like additional performance in both that
     plane and my Electra. Sounds like either cobalt is the ticket!
                         
                             Thanks again for your input,
                             
                                            Dan W.

    	I have recently purchased a Great PLanes Electri-Cub.  I expect to
    start building it as soon as I complete my Astro Sport.  The question I
    have for you Electri-Cub owners is:  should I use an Astro 05 direct
    drive or an Astro 05 geared motor.  Of course if someone answers that
    question, then I'll certainly have to ask "what prop did you use"
    followed by "what problems did you have during construction...any
    suggestions before I start on this kit"?
    	I'd like to build the Electri-Cub with snow skis so I can fly
    during the winter(I live in Bedford Mass).  Anybody ever build snow
    skis for a tail dragger??  Any suggestions?
    
    						
    						regards
    
    						

    
    	Another question in a slightly different area of electric powered
    flight.......
    
    	I enjoy building and flying "different" model aircraft.  By
    different I mean something unusual such as a flying wing or a canard
    model.  I'd like to build something along these lines over the winter
    and I don't mind doing a scratch built model.  However, I can't seem
    to find any electric powered flying wings or other unusual
    configuration models....either in kit form or just the plans.  
    	Does anybody know of any kits or plans available for 05 Cobalt
    motors that are not your average Cessna or Piper configuration?
    
    	Second question....
    
    	A couple of notes back, .28 I think, somebody was building a
    Goldberg Mirage.  How did it turn out??  Did it fly well?  What
    radio/motor etc did yo use?  How much did it weigh??  
    	I know that's more than one question but I'm curious about the
    model.  How about some details??
    
    						regards
    						Bob  

    
     Bob,
    
      As an Electricub owner, I will try to answer your questions.
    
      I believe the "Prefered moter is an 05 cobalt geared. I put an 05
    cobalt direct drive in mine for 2 reasons. I wanted to use it in other
    planes that were set up for direct drive, and it also turns a more
    "scale" size prop. To get the advantage from the geared motors, you
    generally need to use a large prop.
      I have had success with 8/4, 8/6 and 9/4 props. I tried a 7/4 once,
    but the plane almost didn't survive to tell about it. A 7/6 may be
    another possibility, but after all by experimenting, and 8/4 seem's
    to give the best balance of performance and flight duration.
      I usually get 3 1/3 - 4 minutes with a 1200mah 7 -cell pack, and
    5 - 5 1/2 minutes with a 1700 mah 7 cell.
      The plane climbs pretty well, and I have recieved a number of nice
    comments regarding its flight performance. I tried a few ROG off
    grass, but the take-off was marginal with no room for error. I would
    use the 9/4 prop if you are intent on doing takeoffs. 
      Contrary to advertized, the plane does not glide particularily well.
    at the end of your battery run, you need to be near the landing area.
    I installed the landing gear, and the optional struts to give it a 
    more scale appearance, but several people leave one or both off to
    gain performance.
      I used the Futaba AM conquest with the combination Speed control/
    reciever, although you can probably get by with an on/off arrangement.
    
        Building tips:
    
    
          - try to use every tip they include in the supplemental booklet,
            it does make a difference. I drilled out all the area's they
            suggested (and then more!)
    
          - use micro servo's (especially if you are using a seperate
            receiver battery to save weight.
    
          - I used Black Baron film to cover (It kept the weight down, but
            it doesn't seem to have the durability of Monocote.)
    
          - The cowling gets easily beat up during crashes. If you are
            crash prone (Like me) you may want to order a couple more 
            upfront for spares. Also, Fiberglass Masters makes a
            replacement cowl for the cub $7.50 , but it requires a lot
            of work to fit and get light.
    
                                                    
          - Covering the plane was straight forward (Black baron helped
            when doing the wing tips, it gets tricky).
    
          - If you are going to install a tail wheel, you may want connect
            some support to it. In the standard configuration, the
            Tailwheel connection is very flimsy.
    
    
          - Be careful when gluing the tail end of the longerons together
            to get proper alignment, and make sure the tail feathers are
            properly aligned.
    
    
          - Don't use the servo tray provided, make rails to save weight.
    
    
          Have a ball, it is fun to fly, and I have recieved many
          unexpected compliments from people who have seen it fly.
          If you have any questions during construction, give a yell, maybe
          I can help.
    
             I was thinking about the Ski thing myself, but I have pretty
          much dismissed it due to drag and weight. Maybe you have some
          idea that will work, if so, I'd love to hear it.
    
             I was the one who made the Mirage entry awhile back. I haven't
          built it yet because my wife played a dirty trick and bought me
          an Electrostreak in the meantime, so I built that first. I think
          the Mirage will fly well, maybe even a little better the Cub.
          I have read good write-ups on it.
    
                                           Good Luck,
    
                                           Dan Weier 

    I'm an E-Cub owner, too.  I've had a lot of success with this plane.  It
    uses a direct drive Cobalt 05.  I've tried props from a 7-4 to a 9-5.
    The TopFlite 7-6 nylon seems to work the best (if you can find 'em).
    Flight is acceptable with a 6 cell back, but more respectable with a 7
    cell.  Leave off all the silly scale details (struts and fake motor
    heads) they just add weight and drag.  Use Dave brown Lite-Flight wheels
    instead of DuBro's.

    I found that my plane needed some significant down thrust before it
    would fly well (I knew it was that, 'cause it glided just fine with the
    motor off).  You should put some in (use a thin 1/16 shim under the back
    of the motor), too much is relatively harmless, not enough can be a real
    problem.  Be sure to drill out the firewall.  This not only reduces
    weight, but it allows a lot more air to flow through the fuselage to
    cool the battery (a consideration not provided for in the plans).  Also,
    make a small (1/4 inch square) hole at the very back of the fuselage,
    on the bottom, so that the air can flow out (also not suggested in the
    plans).

    This is a great plane (hah), It flies nicely.  I like it a lot.  I
    recently put a Cobalt 15 in mine (the 05 moved to a glider).  If I can
    figure out a way to reenforce the landing gear without adding too much
    extra weight (the additional battery really bums out the piano wire
    gear) I might even fly it soon.  I expect it to perform much better with
    the 15, and provided you haven't bought your kit yet, you might want to
    go this route.  A 15 powered E-Cub has a 100% increase in power, with
    only a 25% increase in weight, over the 05 powered version.  This
    difference would make it a much better beginners plane.

This note has been very quiet for some time. Hope someone will still see (and
read) new entries.

With the building season approaching, I am looking forward to start building
an ElectriCub. My question is what motor to use. I plan to make it look scale-
like (with struts and engine dummy) and would like to cover it with one of 
those fabric-looking iron-on coverings. If at all possible, I'd like to prepare
for a possibility to carry a small camera (I already have it and can make it 
fit).

Is the ASTRO 05 still the best bet or are there new experiences? Has anyone
tried or seen the geared version? What kind of prop would it use? Is it really
too 'unscale' to consider it? What about the experiences with the ASTRO 15 so
far? Did it really improve performance? What batteries and props did you use?

I would like to stick with 6-cell packs in the first place since I have 4 of 
them, but I might consider bigger battery packs. I already have an ASTRO COBALT
05 that I use with 6 cells in my Kormoran (but I reversed it for the pusher 
prop and adjusted the timing, so I don't want to use this for the Cub), but it
works very well with an 8.5 x 5 prop.

I would be very happy with quick answers, since I currently have a chance to
get a motor from the US, but have to order it today or tomorrow (ASTRO motors
are about double the price here in Germany, in the same range as COBALT motors
from here as GRAUPNER ULTRA, ROBBE KELLER etc.).

Thanks in advance, and best regards,
                                       Hartmut

>Is the ASTRO 05 still the best bet or are there new experiences? Has anyone
>tried or seen the geared version? What kind of prop would it use? Is it really
>too 'unscale' to consider it? What about the experiences with the ASTRO 15 so
>far? Did it really improve performance? What batteries and props did you use?

    For the 15 seconds it stayed in the air before it rolled over and
    stuffed-in, my E-Cub with a direct drive Astro-15 turning an 8-6 on 12
    Sub-C cells flew great.  Climb-out was 25+ degrees right out of my hand
    with no run-out to gain speed.  As big an improvement as the Astro-05
    has over the stock Goldfire, the 15 has over the 05.  Well worth the
    cost.

    Beware:  I had no radio noise problems with the Cobalt 05, but did (and
    I stupidly failed to check before the first flight) with the 15. 

    I'm rebuilding it now and hope to try again soon.  I'll be using an FM
    radio this time, with Failsafe set to shut off the motor.

    Randy

    Between Christmas and New Year, I finally got started on my ElectriCub
    (Al Ryder, are you reading this?). Although I had not quite finished
    the RACE CAT (as I had promised). The wing of the RACE CAT is still
    uncovered, but since someone borrowed my heatgun and didn't give it
    back before the holidays, I was 'forced' to start the new kit. In the
    meantime, I've got the heatgun back, but I enjoy buiding the Cub so 
    much that I could not yet put it aside to get the RACE CAT done.
    
    Yesterday, I put the fuse sides together and installed all back formers
    and the aft deck base. With my building speed, this project might take
    most of this year until finished, but I enjoy it a lot. This is the
    first all wood kit after my restart 3 years ago, so it must be about 15
    years since I last built an all wood plane. It's just plain fun to see
    the parts go together, and with the CA glue these days... wonderful!
    Can you tell I'm having a good time building it?
    
    Of course, I cannot build stock planes any more. As said some notes
    ago, I want to try to carry a small camera onboard. The camera is
    already prepared with a Futaba micro servo and working nicely as an R/C
    camera. Only thing is I had to 'rework' the former F2 to get the camera
    into the CG to allow easy taking in and out without moving the CG. This
    makes building a little more delicate since I had to rearrange some
    lightening holes in the structure for the cutout for the camera and the
    new location of the upper part of former F2. I need to save some weight
    to at least offset part of the camera weight, on the other hand I think
    I can't give up any stability BECAUSE I want to carry additional
    weight. 
    
    Since my request 2 replies ago was not answered in time, I went ahead
    and ordered an ASTRO Cobalt 05. With micro servos, a small BEC motor
    controller and trying to build light (will probably give up to try
    fabric type covering), I hope this will be sufficient to get it flying
    with reasonable performance. I plan to do some prop testing to achieve
    maximum efficiency.
    
    We'll see how it works out. I'll keep you all posted.
    
    Best regards,
                    Hartmut
    

    RE: -3 Sorry for delayed response to your 05 question. I really think an
    05 geared would run much better. Kay is running an 05 geared in his
    electric cub and I'm running a geared 05 in my mirrage (similar size
    and style plane) and it runs much better. With the added weight of
    the camera I think you will need a geared motor. In my opinion direct
    drive is for Race Rat, Electro-Streak and F3E and Gliders and trainers
    should be geared.
    
    RE: -2 What type of radio did you use (AM, FM, PCM) when you got the
    interference problem on the 15.

    
      I second it! I had an Electricub with an 05 cobalt direct drive, and
    I wasn't impressed. I would do geared if I did it again. The geared
    power train is much better suited to the slow flight characteristics
    of the cub. 
    

>                   <<< Note 408.36 by KBOMFG::KLINGENBERG >>>
>                -< ASTRO 05 still the best for the ElectriCub? >-
...
Is the ASTRO 05 still the best bet or are there new experiences? Has anyone
tried or seen the geared version? What kind of prop would it use? Is it really
too 'unscale' to consider it? What about the experiences with the ASTRO 15 so
far? Did it really improve performance? What batteries and props did you use?

Sorry I didn't answer earlier but I felt then that I wasn't truly qualified
to comment.  I'll just explain why.  Yes I'm running a geared Astro 05
in my Electric Cub but...

1.  I didn't build the plane I purchased it at auction so could it be lighter
    or stronger?  Who knows.  Could the wing have been straighter - yet.
2.  I never ran the stock motor.
3.  I didn't use the Astro gear reduction - I purchased the Master Airscrew
    gear reduction unit to save a few bucks.  It seems to work OK but is
    very cheaply made - I wish I had sent to Astro for theirs.
4.  I had to reverse the timing on my 05 because I added the gear reduction
    unit after the fact.  I'm not at all convinced that it is properly
    timed.  It's close enough but since I hit a mechanical limit and since
    I really can't easily vary it a degree or two between flights I'll probably
    never know for sure.
5.  I have yet to run it on the intended battery pack.  I have only flown off
    a 7 cell 900 mah SR pack that I've had for years and I blew out one cell
    before the first flight so I have one 800 mah cell in the pack - a week 
    link.  I have mistreated and overheated this poor old pack many times.
6.  I haven't yet settled on the final prop size because I have two brand new
    1500 mah 7 cell packs that I will charge up as soon as my new Astro
    peak charger arrives.

>I would like to stick with 6-cell packs in the first place since I have 4 of 
>them, but I might consider bigger battery packs. I already have an ASTRO COBALT
>05 that I use with 6 cells in my Kormoran (but I reversed it for the pusher 
>prop and adjusted the timing, so I don't want to use this for the Cub), but it
>works very well with an 8.5 x 5 prop.

Now that you have added the gear unit your timing should still be correct
but look at 11x7 as a starting point for props.

It will probably fly fine on the 6 cell packs but if you stick one 7 cell pack
in for one flight I predict you will never want to fly off 6 cells again.

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################

    
    Which charger did you order Kay, I'm waiting for mine also :-). I agree,
    7 cells geared seems to be a magic combination. I know how you feel
    having all 6 cell packs. I have 4, 7 cell packs and need to run 8 or 10
    cells in my newest plane. What I think I'm going to do is rip apart my
    "worst" two packs then take the best cells and buy some extra cells and
    build two good 8 or 10 cell packs.
    

Thanks for the replies!

Still, since I got the new ASTRO 05 now, I think I'll at least use it as a 
starting point. I was (and still am) thinking along these lines:

1. ASTRO Cobalt 05 direct drive seemed to be the most recommended (by noters) 
   motor until recently.

2. Theory says that the geared motors/big props have an advantage on slow
   flyers (Electra etc.). The faster the plane is, the less advantage have
   gears. And the higher efficiency of the prop has to make up for some losses
   in the gear, this means the output power of the motor is definately less
   with the gear.

3. My experience with my GRAUPNER Electro-UHU taught me that it's about the
   edge of where the difference is noticable. I flew it with the SPEED 600
   direct drive and the SPEED 600 geared (3:1). There is some drop in current
   and maybe (not quite sure yet) a slightly increased climb rate, but it can't
   go as fast as it used to any more. The increase in performance is noticable,
   but not dramatic. I expect the Cub to be in a similar speed range.

4. If the experiment with the camera works out well, the main thing it'll do
   is increasing the wing loading and therefore the speed. This drove the 
   decision in the direction of direct drive (maybe with a higher pitch prop 
   with camera/lower pitch without camera).

5. The Kormoran (similar size) flies very well with the direct drive Cobalt 05.

6. If I should find out that I'd like to try geared, I can still use the
   reversed Kormoran motor and add a gear.

Thanks for the inputs anyway. If they had come earlier, I might have ordered
a geared 05. Now that I have the brand new direct drive dedicated for this
plane, I at least want to try it out.

BTW, Kay, I experienced the same thing when I reversed my Cobalt 05 for the
Kormoran: mechanical stop. Now if you take the screws out (I'm not sure whether
you hav to take them fully out), you can turn the stator further and insert the
screws again. You'll find that the optimum (max rpm/min current) is near the
point where you first had the block, but you can adjust around this point now.
Hope it works out for you as well...

Best regards,
              Hartmut

    	Need help, I was just looking in the 92 Tower catalog and I'll be
    damned if I can find the Electricub in there, can somebody help, I
    looked twice and cant find it, I'd like to order the kit w/out the
    motor.
     

    Check in the front section of the catalog...  Since it is a Great
    Planes kit, it is in the front section, not in the "Airplane" section.
    
    Also, be sure to use the order number from a Tower Talk as it is
    usually cheaper than the catalog price.
    
    cheers,
    jeff
    

I just got an order yesterday and in the close out sale section
they listed an electro cub for $37.99.

My guess is that they are no longer going to sell them in the future.

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################