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Conference vmszoo::rc

Title:Welcome To The Radio Control Conference
Notice:dir's in 11, who's who in 4, sales in 6, auctions 19
Moderator:VMSSG::FRIEDRICHS
Created:Tue Jan 13 1987
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1706
Total number of notes:27193

1558.0. "Tow plane recommendations wanted" by UNYEM::BLUMJ () Wed Sep 15 1993 10:15

    Due to the great success I have experienced in having my Multiplex
    glider piggybacked up, I am thinking about building my own
    tow/piggyback plane.
    
    I was taken up this weekend by a Senior Telemaster with a Saito .90
    twin 4-stroke spinning a 14-6 prop.  My glider weighs 5 lbs. 
    Climbout was adequate but not great.  The Telemaster owner says 
    that the Saito is a "mild" engine powerwise.
    
    Anyway, the Senior Telemaster seems like a good towplane because
    it is large, inexpensive, and has docile handling.  Are there any 
    other planes that would be well suited to towing?
    
    When I posed the question of engines to a couple of club members
    with the qualification - "the most power at the lowest price",
    they recommended a .65 K&B Sportser, claiming that it would
    be more powerful than the Saito.
    
    Any other engine recommendations, assuming the airframe will be a
    Senior Telemaster?
    
    The nice thing about the Saito is the exhaust stacks point downward
    so no oil got on the glider.  Is there a way to divert the exhaust
    on a 2-cycle engine to achieve similar results?
    
    I would like to piggyback/tow gliders up to 10 lbs weight.
    
    Any help appreciated - I have no wet power experience.
    
    
                                                Thanks,
    
                                                Jim
    
      
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1558.1Telemaster a Good ChoiceLEDS::WATTWed Sep 15 1993 10:2617
    Jim,
    	I would agree that the Senior Telemaster is a good choice for a tow
    plane.  You want good slow speed handling.  I think that the K&B is a
    hunk of junk however.  It's cheap so maybe you gets what you pay for. 
    A 2-stroke is going to put out plenty of oil and once it gets into the
    slipstream, it will go on your glider if you are towing it.  If you
    piggy back it, you can mount the engine with the muffler pointing down
    and the head pointing out the side.  4-strokes burn most of the oil so
    you get much less on the plane.  My OS91 puts out oil from the breather
    nipple but you can divert this using fuel tubing.  If you can afford a
    4-stroke I think it would make the best engine for towing.  A good 90
    size engine should have plenty of thrust.  There are a bunch of 60
    2-strokes out there that would have similar performance to a 90
    4-stroke.  Use a big diameter, low pitch prop for towing.
    
    Charlie
    
1558.2Is a .60 enoughUNYEM::BLUMJWed Sep 15 1993 11:5413
    Charlie,
    
    
           Do you think a 2 stroke .60 would have enough guts to
    haul up a Telemaster with a 10 lb glider on its back?
    
         
                                                   Thanks,
    
                                                   Jim
    
    
    
1558.3Remember to include both planes weightGAUSS::REITHJim 3D::Reith MLO1-2/c37 223-2021Wed Sep 15 1993 12:028
Probably not. You have to figure that the engine will need to carry 
both the plane and glider weight. I would expect that a 4 stroke motor
with it's better torque would do better at getting this into the air. 
Thing of the 4 stroke as a gear reduction unit and you should be able 
to get a large plane up to altitude with a big prop on a 1.20 4c

For a 15 pound combination you might want to try a ST .90, OS 1.08, or
a reasonable 1.20 four stroke.
1558.4Include both planes Wings alsoLEDS::WATTWed Sep 15 1993 14:517
    A good 60 would probably do it if you have ample room for a takeoff
    roll.  You get the added lift of both wings so the wing loading is very
    light.  If a 90 4-stroker would do it, a 60 2-stroker would do it. 
    Trick is to use the right prop for the job.  I'd try a 12-6 or a 13-6.
    
    Charlie
    
1558.5GAUSS::REITHJim 3D::Reith MLO1-2/c37 223-2021Wed Sep 15 1993 15:052
I was saying a ST .90 2 stroke/1.20 4 stroke. My thoughts were that you'd 
need a little more power for most typical power fields (read CMRCM types)
1558.6OK but Don't Need That MuchLEDS::WATTWed Sep 15 1993 15:485
    You don't want a Rocket Ship to tow a glider.  I still say a 60 will do
    it with a Telemaster.
    
    Charlie
    
1558.7GAUSS::REITHJim 3D::Reith MLO1-2/c37 223-2021Wed Sep 15 1993 16:024
The other side of the coin is that you won't always be flying with a 
10lbs glider so you're probably right. It's generally easy enough to 
swap engines/mounts on something like this so you might want to borrow 
and engine to try before you spend the money.
1558.8Tugs should be bigKAY::FISHERThe higher, the fewerWed Sep 15 1993 17:3615
I would vote for a Balsa USA quarter scale cub with a Webra Bully
or equivalent - that is what Kevin Ladd had and we towed his Airtronics
Olympic II up with it.  The Oly is very light - but it also had a tendency
to go too fast.  With a nice heavy glider piggy packed it should be nice.

Anyway - think giant scale.  Also there is almost no mess to the exhaust from
the gasoline engine.

Just my 2 cents worth.

Bye          --+--
Kay R. Fisher  |
---------------O---------------
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1558.9A tip..CSTEAM::HENDERSONCompetition is Fun: Dtn 297-6180, MRO4Wed Sep 15 1993 17:4218
    There is a secret to this glider towing stuff. 
    
    The tug has to be able to fly at a slow speed and not stall. No matter
    how big an engine you put on the glider will be faster. (Assuming that
    it is not a polyhedral floater).
    
    So what you need is a strong 61 for the plane in question. 
    
    You fly the glider below the tug at all times. 
    
    You climb gently say 5-10 degree angle.
    
    You will probably not need full thottle once you are airborn.
    
    My 2 pennath - E.
    
     
                     
1558.10some thoughtsKBOMFG::KNOERLEThu Sep 16 1993 06:5420
    
    A year ago we had the Multiplex Super Glider Cup (free translation)
    held at our clubs field. There where three tow planes :
    - One Jodel with ZG62 and flaps
    - Two Piper Cubs with ZG38 as backup ship.
    As the tow plane was flying all day, the gazoline engines are the best
    choise : cheep fuel and very reliably running. They also towed the
    biggest glider up to a hight of 150 meters in very short time.
    I'd say use an engine with as much torque as you can get for short
    takeoffs and a_quick_gaining_safety_altitude.
    How's about the ZG22 on a Senior Telemaster !  Much cheaper than a 120
    4-Stroke for shure. 
    In our club we had a Big Lift from Multiplex with a Webra 90 2-stroke
    doing this picky-baging_carrying (???) pulling up the biggest gliders.
    I think a 60 size engine for a 10 lbs glider tow is marginal.  
    
    My 3 cents,  Bernd
    
    
    
1558.11Gas engines?UNYEM::BLUMJThu Sep 16 1993 10:0816
    Thanks for all the replies.
    
    If I were part of a gliding club where a tow plane was being jointly
    purchased/maintained, I would certainly opt for a big powerful
    setup.
    
    At this time a 1/4 scale towplane with a $400-$500 engine is beyond
    my budget.
    
    Are the Quadra gas engines cheaper than 4 strokes of commesurate power?
    What prices are we talking about?
    
    
                                                   Thanks,
    
                                                   Jim
1558.12# cents???.CSTEAM::HENDERSONCompetition is Fun: Dtn 297-6180, MRO4Thu Sep 16 1993 15:4010
    2 cents Bernd, 2 cents! 
    
    :-)
    
    
    Howdy stranger. How are you keeping?.
    
    Evl-1.
    
    
1558.13well,KBOMFG::KNOERLEFri Sep 17 1993 09:4819
    
    Howdy yourself !
    
    My thoughts have been off the subject lately. You know, learn how to
    use WORDS for windows, how to create a Postscript file on a PC, how to
    transport your PC_created .PS file onto your VAX-account and print on a
    nice Laser Printer and so on. 
    I guess that our (Hartmut and myself) entries could be read till end of
    March. Then ex....
    
    
    Back to the subject, a gazoline engine is much cheaper than those
    4-plopers. I think to remember that I payed $275.- or so for my ZG62,
    and this is ONE powerhouse !  The one Quadra I had I got rid off before
    I've put it in an airplane. I thought it had some vibrations. If you
    would choose the ZG22 I would imagine the costs beeing 200 bucks or
    below. And this is one fine little mill as the magazines state.
    
    Bernd
1558.14Nice one.CSTEAM::HENDERSONCompetition is Fun: Dtn 297-6180, MRO4Fri Sep 17 1993 12:031
    FOUR-PLOPERS :-)
1558.15Don't forget the RobinHoodsASABET::ANKERAnker Berg-SonneFri Sep 17 1993 15:2111
        Re:<<< Note 1558.14 by CSTEAM::HENDERSON "Competition is Fun: Dtn 297-6180, MRO4" >>>

        I once  has  a  RobinHood  80  which Dan Snow had tired of before
        getting to covering  it.    The  power was a Maloney 125 gasoline
        pumper.  This plane  was  just fantastic and would be the perfect
        tow plane.  My concern  with  the  Telemaster is that it is light
        and has a light wing loading.  A heavier plane, that also can fly
        slow, is better because the glider can't  as  easily  get it into
        trouble.
        
        Anker
1558.16Robin-Robinhood?UNYEM::BLUMJTue Sep 21 1993 12:0319
    I have received and reviewed the Aerotowing video advertised in
    RCSD.  The video was made by John F. Clarke and features Robin
    Lehman's 24 ft. Grob and 27 ft. LS4 sailplanes.
    
    3-meter and 4-meter sailplanes are also shown being towed.
    
    The towplanes used were ROBINS, one had a Quadra G62 and the
    other a Quadra 100.
    
    I wonder if a ROBIN and a ROBINHOOD are the same plane?
    
    The ROBIN in the video was a high wing design that appeared to be
    about 80" in span.
    
                                           
                                                           Regards,
    
                                                           Jim                  
             
1558.17It may beASABET::ANKERAnker Berg-SonneTue Sep 21 1993 14:4210
        Re:                      <<< Note 1558.16 by UNYEM::BLUMJ >>>

        I wouldn't  know,  but the description is similar.  The RobinHood
        is a way-off-scale  model  of  the  Curtiss  Robin - a boxy, ugly
        plane from the 20's  and  30's.    The wierdest, and most easy to
        identify part of a Curtis Robin is the windows.  The side windows
        have a triangular piece going down  twoards  the  floor,  I would
        guess so the pilot can see the landing gear!?
        
        Anker
1558.18G-38 Good Tow EngineLEDS::WATTTue Sep 21 1993 15:049
    I have an Ultrahots with a G-38 Zenoah in it and that engine would work
    very well on a 10 pound tow plane.  It's very reliable and has lots of
    pulling power.  For towing, you want good acceleration of the tow
    plane to get the glider airborne and controlable.  I assume you're not
    talking Gentle Ladies or Spirits here.  They would require a fairly
    slow tow plane to keep them controlable.
    
    Charlie
    
1558.19TRY A ST .61 ABCNEMAIL::YATESTue Sep 21 1993 15:1322
    Charlie,
    
    I built the Sr. Telemaster and used a ST .61 ABC.  The plane would clear
    the ground within 10 feet with full power on take off.  A note of
    caution if you build one of this planes - ailron flutter is a problem. 
    The ailron is about 3 inches wide and goes the full lenth of the span. 
    With less than full power, I had no problems with flutter.  However,
    with full power, I always experienced flutter.  
    
    I tried gapping the hinge area, reinstalling heavier control wire, etc,
    etc., etc. and nothing would cure it.  The plane crahsed into a pile of
    toothpicks after the 8th flight.
    
    The manufacturer (Hobby Lobby) now recommends that two servos be used,
    one in each wing to eliminate flutter (boy, can I now agree with that).
    
    The ST .61 ABC would fly this plane on low throttle and I would think
    that piggy-baking a glider would be no problem.
    
    
    Ollie
                                    
1558.20Flutter fixFULCRM::WALTERTue Sep 21 1993 16:459
    Just as an aside, I remember an article in one of the RC mags a couple
    years ago that explained how to eliminate flutter in a surface. It
    involved attaching a weight to the surface by a rod, with the weight 
    AHEAD of the hinge line. That would move the CG of the surface forward,
    and apparently stops the flutter. I don't remember the theory behind
    what causes the flutter and why this solution works.
    
    Dave
    
1558.21Speed KillsLEDS::WATTTue Sep 21 1993 16:4710
    Even the smaller Telemaster has big flutter problems is you use a
    single servo and belcranks.  Two servos and SHORT linkages are a must. 
    Also, the plane is not designed to fly at full throttle with a 61 in
    level flight.  It is a slow flying airplane.  The extra power would be
    nice for a tow plane but you don't need excess speed.  Keep the prop
    pitch low and diameter large.  Flutter almost always destroys the
    airplane!
    
    Charlie
    
1558.22Flutter MechanismLEDS::WATTTue Sep 21 1993 16:5213
    Dave,
    	Balancing the aileron/elevator reduces flutter by removing the
    means of oscillation. (positive feedback)  It has to do with which way
    the surface moves due to the dynamics of the wing.  An unbalanced
    aileron will move down when the wing TE moves up.  A balanced aileron
    will not tend to move up or down if the wing translates up.  Flutter is
    a mechanical resonance which when induced will increase in amplitude
    until something either reduces the amplitude or the structure fails. 
    The stiffer the structure the higher the "flutter speed" will be.
    
    
    Charlie
    
1558.23Robinhood 99KBOMFG::KNOERLETue Nov 02 1993 10:457
    
    I once bought a Robinhood 99 and a Quadra35. As it says, 99 inches is a
    big plane. I sold before built and saw it fly later on. Very nice,
    stable and slow. Could imagine a ZG38 as a perfect match.
    
    better late than never,   Bernd
    
1558.24Telemaster coming upUNYEM::BLUMJTue May 10 1994 09:3812
    I ordered the Senior Telemaster plan from Hobby Lobby yesterday.
    
    This will serve as a trainer to teach me power flying and then
    assume it's role as a glider towplane.
    
    The wing will be beefed up a little and utilize two guy wires to
    increase the + G load ability.
    
    The fuselage will be substantially beefed up to accomodate a 
    modified chainsaw engine.
    
    Looking forward to this new aspect of flying.
1558.25Two hooks?CSTEAM::HENDERSONCompetition is Fun: Dtn 297-6180, MRO4Tue May 10 1994 10:0212
    When Charlie and I did Tow Planes we rigged a release on BOTH planes.
    This is just in case the glider cannot activate its own release. The
    glider will fly just fine and can be landed with a tow wire hanging off 
    its nose.
    
    The pull forces up there can be very great so I thought you might want
    to consider building this safety feature into your project.
    
    
    Regards,
    
    Er
1558.26WRKSYS::REITHJim WRKSYS::Reith MLO1-2/c37 223-2021Tue May 10 1994 10:322
I've been thinking about using Chrlie's Hots. I think the cradle I saw would fit
better on top of a Panic wing...
1558.27UNYEM::BLUMJTue May 10 1994 10:4812
    Re: -2
    
    This is a good idea, and will be incorporated on the towplane.  This
    way the towplane can initiate a release if sime problems occurs with
    the glider tow release.
    
    Re: -1
    
    Robin Lehman has aerotowed with his 1/4 scale Laser, but claims it is
    harder than with the Telemaster because the plane is faster and less
    stable.  If the HOTS lacks low speed stability it might not be a good
    towplane.
1558.28Lift vs. pullUNYEM::BLUMJTue May 10 1994 10:5713
    I have now had the experience of being aerotowed and lifted using a
    crutch on the top of a power plane wing.
    
    The crutch is by far the easier method, requiring only a powerful plane
    and gentle flying by the power pilot.  Orientation between the two
    aircraft is not an issue, as they fly as "one".
    
    Aerotowing is much more difficult, requiring releasable towhook in
    the glider and skilled pilotage by both the glider and the tow plane.
    Orientation of the two planes at altitude, I have found difficult.
    
    For non-scale saiplanes, I would recommend the crutch method because
    it is much simpler/safer.
1558.29Twin rudder questionUNYEM::BLUMJTue May 10 1994 12:1316
    One further modification I would like to explore for the
    Telemaster/Towmaster is twin rudders.  The sailplanes I would like
    to place in the crutch are longer than Telemaster.  The twin rudders
    mounted at the ends of the stab would allow the sailplane fuselage to
    rest between them.
    
    Since the proposed chainsaw engine will be much heavier than the
    typical Telemaster powerplant, I do not think the added weight of
    the twin rudders will be a problem.
    
    Has anyone dealt with twin rudders in the past?  Any suggestions on
    construction and linkage?
    
    Thanks,
    
    Jim
1558.30WRKSYS::REITHJim WRKSYS::Reith MLO1-2/c37 223-2021Tue May 10 1994 12:2415
the GremTwin I fly has twin rudders. I use horns on the inside and run them from
opposite sides of the servo wheel. 

	          _______rudder
	|---------|
	|
	o servo horn
	|
	|---------|
	          -------rudder
	

You can also add a crosslink betweek the rudders and move just one.

I've seen this modification used... Just look at the Shuttle Carrier 747 8^)
1558.31twin rudder sizeUNYEM::BLUMJTue May 10 1994 12:527
    re: -1
    
    Thanks for the idea Jim.
    
    I wonder if when using twin rudders you can half the size of each vs
    a single rudder.  In other words, the two fins/rudders would equal
    the area of a single fin/rudder?
1558.32Avoid FlutterNEMAIL::YATESTue May 10 1994 13:0915
    re: the Telemaster - I strongly suggest that you use servos in each
    wing (possibly even 1/4 scale servos) since I lost my Sr. Telemaster
    because of wing flutter.
    
    The strip ailerons are so big that there is no way to keep them stiff 
    since they run the full length of the wing.  I used a ST .60 for power
    and it flew great at 1/4 throttle.  However, at full throttle, the
    flutter would start and required backing off the power immediately
    (until one flight, I backed off too late and the big thing went in and
    I gathered about 10,ooo toothpicks after the crash.
    
    Take off at full throttle took about 5 feet.  It a great plane to fly
    if you can avoid the flutter.
    
    Ollie                        
1558.33MISFIT::BLUMTue May 10 1994 14:294
    re: -1
    
    Were the ailerons sealed to prevent air leakage between upper and lower
    wing surface?
1558.34towing - more generic approach?QUIVER::WALTERTue May 10 1994 16:069
    Getting back to towing vs. carrying, it seems like towing would present
    fewer problems in matching the glider to the towplane. When using a
    cradle, the glider has to fit snug in the cradle, with proper
    alignment, and don't mess up the CG. For example, when we launched my
    Predator using Eric's cradle, we had to do some major shimming because
    the Predator is a high wing design and the cradle was designed for a
    low winger. Don't have to worry about that stuff when you're towing.
    
    
1558.35UNYEM::BLUMJTue May 10 1994 17:2721
    RE: -1
    
    Dave,
    
        I don't know what Eric's cradle is like, so I can't comment on
    it's operation.  The cradle we use works the same for any wing
    configuration(high,low,mid).  No shimming or anything is needed,
    you simply set the glider on the cradle and wrap rubber bands around
    the wings.  It is foolproof.
    
    Getting a releasable towhook in the nose of the average sport glider
    design could be a little tricky(or impossible!).
    
    Glider pilots of any skill level can utilize the cradle, where I would
    rate the skills for aerotow much higher.
    
    Both methods work well, it just depends on your preference.
    
    My father's club has successfully taken up a Multiplex flamingo glider
    that weighs probably close to 100 oz. with a Telemaster 70 using a
    fox .50 engine.  This really shows how powerful these engines are!
1558.36Gapped Hinges-YesNEMAIL::YATESTue May 10 1994 17:409
    On the flutter issue, yes the hinges were gapper with Granit State
    cloth hinges. Also, I installed heavier steel push rods from the servo 
    to the torque rods (about 4 inches).
    
    I concluded that one standard servo will not hold the ailerons from
    fluttering when the plane flies at full speed because of the wide width
    and the extreme length.
                                       
    Ollie 
1558.37TUG Tail feathersSHIPS::HORNBY_TSoarers are rarely SilentWed May 11 1994 10:4316
    INFO... I'm not sure if this has been covered..  
    
    TUG Tail feathers and the posible problem of the tow wire tangling or
    hookup..
    
    Two ways I have seen employed. 
    
    1. Some of the german tugs have used V tail.
    
    2. Conventional tail configurations have a wire running from the tip of
    one elevator to the top of the fin and across to the other tip (not on
    the moving parts.)
    
    Trev
    
    
1558.38FlutterLEDS::WATTThu May 12 1994 08:539
    Telemasters are not designed to fly fast - and they will flutter badly
    if you don't do something about the ailerons.  I've seen it happen
    several times.  Best solution is wing mounted servos and short stiff
    control rods.  Tapering the ailerons helps - but keep the speed down. 
    Most of these things are over powered and that's a major cause of
    flutter.
    
    Charlie
    
1558.39T-master flutterUNYEM::BLUMJThu May 12 1994 10:0213
    The two Senior Telemasters that I am familiar with have not exhibited
    flutter(at least audible flutter).  One is powered by a Saito .90
    twin four stroke(14x6 prop) and the other an O.S. 160 twin four
    stroke(16x7 prop).
    
    Both models use separate aileron servos.
    
    Sure hope mine doesn't flutter!
    
    
    Regards,
    
    Jim
1558.40.CSTEAM::HENDERSONCompetition is Fun: Dtn 297-6180, MRO4Thu May 12 1994 11:063
    Separate aileron servos 1/3 out on the aileron are a winner. 
    
    E.
1558.41Aerotow videoQUIVER::WALTERThu May 12 1994 18:5321
    I watched Jim Blum's Aerotowing video the other night. It's worth a 
    quick view, although I did make liberal use of the Fast Forward button.
    The video is as interesting for the large scale gliders as for the
    towing techniques! They had 1/2(?) scale ASW 22 that was large enough
    to place a small child in the nose. Also shown were an ASK 18 and a
    3M Discus. They used Robin Hoods as tow planes, with two different 
    engine sizes depending on the size of the glider to be towed.
    
    The towing didn't look too difficult. The tow pilot needs to fly
    smoothly in large circles around the field, and the glider pilot needs
    to keep the glider above the tow plane, same as for full size. An
    interesting tip I never would have thought of: the glider should be
    kept wings-flat in the turn, to force it to the outside of the circle
    and keep the towline tight. I would have tried turning with the tow
    plane, and I can see how that might ease the towline tension. 
    
    I'd love to try towing sometime, maybe with the Prophet. Any volunteers
    for tow pilot???
    
    Dave
     
1558.42?WMOIS::WEIERWings are just a place to hang AileronsFri May 13 1994 09:142
    
     I think it would be difficult to have the Prophet tow anything! :)
1558.43VMSSG::FRIEDRICHSI&#039;d rather be flying!Fri May 13 1994 09:412
    The Prophet could tow a Panic as long as you used Jim Reith's winch!!
    
1558.44Towing = long runwaySNAX::SMITHI FEEL THE NEEDFri May 13 1994 11:1124
    DW2...I think watching your "wing" spinning rapidly over the fuse has
    affected your brain. 8^)
    
    Jeff...All that actual going to Florida and back has fried yours also.
    8^)
    
    I think the major drawback to towing in our area is runway length. I
    don't remember reading in these notes how long the tow line is when
    towing RC gliders but I would assume at least 50 feet. In the case of
    CMRCM, you would probably need most of the runway to get airborne
    pulling a glider which means you would have to start off at the edge of
    the runway. That would leave the glider sitting out in the weeds. The
    drop zone would have been good but that's not available anymore. The
    Loopers field would probably work depending on the rate of climb that
    is normally achieved. For this area, the cradle is probably the most
    universal as far as field usage goes.
    
    I could be wrong, but I also think ailerons make a big difference when
    considering towing (on the glider). I think the dihedral found on most
    non-aileron glider wings becomes an obstacle when towing. Airspeed
    becomes critical, and if too much airspeed is achieved, the glider
    tends to swing from side to side and eventually flips over. I think Kay
    has some experience with this being with Kevin Ladd trying to tow an
    Oly II.
1558.45Cradles - thumbs down.CSTEAM::HENDERSONCompetition is Fun: Dtn 297-6180, MRO4Fri May 13 1994 11:2522
    The cradle method has a lot of drawbacks. The first being that it needs
    a different seat for every different model. The second is that the
    cradle needs to be very securely fastened to the power plane. The third
    is that release mechanism has to be both strong and reliable. I have
    seen the release mechanisms jam many, many , many, times.
    
    The Cradle plane also flies like a dog with that drag up there when the
    glider has been released.
    
    Escape from bad situations is difficult. It takes time to separate two
    planes and then you have to avoid each other. Ground handle usually
    sucks and any wind can tip the glider and power plane.
    
    Last but not least the glider wings are usually to weak to be tied down
    to the cradle.
    
    If I thought they were worth it I would do a write up but obviously I
    don't advise their use.
    
    Regards,
    
    E.
1558.46HArder than it looksUNYEM::BLUMJFri May 13 1994 11:5624
    I concur with Dave's assesment of the aerotow video.  It's pretty
    boring, but at least outlines the equipment and methods needed to
    successfully aerotow.
    
    Re: Difficulty of aerotowing
    
    I have seen this done only the last two weekends, so my experience is
    based on limited examples, but I will recount what I have seen.
    Robin has done a lot of aerotowing and has very few problems piloting
    the glider.  It appears his power flying skills are not as good.
    Chuck is regarded as a good flyer.  Two weeks ago he brought out a new
    1.20 powered Sukhoi and put on a pretty good show after it was trimmed
    out.  Later he piloted his Multiplex Fiesta glider for two aerotows,
    experiencing minor problems on one tow and severe problems on the
    second where he actually went inverted and nearly stalled the towplane!
    Me- I have two aerotows under my belt and experienced some careening
    problems which required me to get off at decent altitude.
    
    What you have is a mixed bag of skills between Robin, Chuck, and
    myself.  IMO, aerotowing is a little trickier than it looks when you
    see it done by experienced people(sound familiar).  It appears that
    proficiency in power flying or conventional glider launch methods
    will not insure success in aerotowing.  You need to get the hang of it
    through doing it - be ready for surprises!
1558.47Add drag to avoid weaving.CSTEAM::HENDERSONCompetition is Fun: Dtn 297-6180, MRO4Fri May 13 1994 12:2415
    Charlie and I never did "slow" Aero towing. We perfected the full power
    60 degree climb and bail out when I could not see the glider any more.
    The glider was small however. An MM Avenger slope aerobatic jobby.
    
    I do recall talking to some UK tow-folks who said that the glider in
    tow was always too efficient so they added drag with flaps and partial 
    spoilers. This made towing a lot easier. The drag was added once they were
    airborne and about 20' up. They claimed that it prevented the glider
    from catching the tow plane up and maintained good line tension. They
    also said it was a good idea to remember to take it all out once you
    were off of the tow :-)
    
    Regards,
    
    E.
1558.48Always climb to avoid weaving?QUIVER::WALTERFri May 13 1994 18:1526
re: -.2
>    IMO, aerotowing is a little trickier than it looks when you
>    see it done by experienced people(sound familiar).  It appears that
>    proficiency in power flying or conventional glider launch methods
>    will not insure success in aerotowing.  You need to get the hang of it
>    through doing it - be ready for surprises!

Hey, crawling up that learning curve is half the fun! And I love surprises...

re: -.1
>    I do recall talking to some UK tow-folks who said that the glider in
>    tow was always too efficient so they added drag with flaps and partial
>    spoilers. This made towing a lot easier. 

The video stressed that the tow plane should maintain a steady climbout. I
imagine that tended to keep the line tight, along with the g-force of the 
constant circle. However, I'll bet that as you get to high altitude, it 
becomes hard to see and maintain the attitude of the planes. This is probably
where experience comes in.

I still wanna try it. And no, I didn't mean that the Prophet should do the
towing! (Wotta bunch of rubes!)

Dave

    
1558.49I'll Give it a GoLEDS::WATTTue May 17 1994 08:5310
    I have tried both and I would prefer towing to carrying the glider in a
    cradle.  The plane was very hard to fly with a glider on it's back. 
    Towing was a breeze.  If I can figure a way to put a tow release on the
    Ultra-Hots, I'll tow with that.  I think it would work well.  It flies
    slowly and has plenty of pulling power for getting off quickly.  I have
    a release mechanism I made for the Unic but I need to figure a way to
    put it on the Ultra-Hots with it's funny shaped fuse and mid wing.
    
    Charlie
    
1558.50one wayUNYEM::BLUMJTue May 17 1994 09:5313
    Don Troxell tows with a Lanier Stinger mid wing.  The tow release
    appears to be fabricated of 1/4 plywood.  Think of a question mark
    shaped "?" piece of 1/4 ply with a piece of music wire running through
    the center.  The music wire is pulled down through the "?" by a servo.
    
    This apparatus protrudes through the top of the fuselage about 1" and
    is mounted just behind the wing trailing edge.
    
    Does this make sense?
    
    Regards,
    
    Jim 
1558.51WRKSYS::REITHJim WRKSYS::Reith MLO1-2/c37 223-2021Tue May 17 1994 10:117
Actually, one of the other things you need to look at WRT the HOP of an engine
is where in the RMP curve this is. If the engine isn't running in that range,
you won't get that horsepower. As will the electrics, you want to prop to be in
this torque/HP range. There are also ranges where the propeller is most
efficient.

Jim
1558.52VMSSG::FRIEDRICHSI&#039;d rather be flying!Tue May 17 1994 10:5810
    Gee, I guess my clipped wing cub with its OS50 FSR would be a good tow
    plane...  And it already has a release mechanism built in!
    
    Only problem though is that it is on floats at the moment!!
    
    I can switch it back if someone in NH wants to try this....
    
    cheers,
    jeff
    
1558.53right place.CSTEAM::HENDERSONCompetition is Fun: Dtn 297-6180, MRO4Tue May 17 1994 11:5218
    It makes sense to have teh tow point/release where it is. 
    The key is to not have the tow point too far away from the CG. This is 
    to avoid the problem of the tow-line overuling the elevator comands.
    
    With the release on the top the worst case scenario is that the plane gets
    forced nose-up now and again.
    
    Ref. a few preious notes about crashes with tow planes. It is adviseable
    to drop the towline, usually over the runway, before landing. You will get
    away with not doing it but now and again you'll get bitten. It does
    depend upon the terrain of course.
    
    E.
    
    P.S. Ref Engine advice. How can I say this diplomatically?
    You have seen the evidence for yourself. You have enough info to make
    the decision. Do not be dissapointed if you do not get an answer to
    prop/engine performance.
1558.54Not RelevantLEDS::WATTThu May 19 1994 13:445
    Rated HP is not very useful when comparing different engine/prop
    combinations.  
    
    Charlie
    
1558.55UNYEM::BLUMJThu May 19 1994 13:556
    RE: -1
    
    I'm finding that out!
    
    
    Jim
1558.56a little more dataSTOHUB::JETRGR::EATONDan Eaton St.Louis,MO,USA, 445-6522Mon May 23 1994 13:4114
Hey Jim,
I took the day off Friday and spent it at our field building a new pavillion to 
replace the one that floated away last year. During a lunch break I asked one
of the club's experts about your situation. Keep in mind that our club has a 
heavy contingent of 1/4 scale and up flyers and the majority of the engines 
are gas. 

The answer I got was you should consider going with something like a G-38. It's
cheap to run, very reliable, and for the amount of power it puts out cheaper to
buy than a glow engine. He streessed this last part. He really feels that the
gas engines give you more available power than the equivalent glow engine. I
guess this gets back to something someone else was saying about engines having
the same horsepower figures but it makes a big difference where the power band 
is located.
1558.57UNYEM::BLUMJMon May 23 1994 14:2423
    Re: -1
    
    Dan,
    
       Thanks for inquiring with your local group, I appreciate any help
    I can get in this arena.
    
    I was reading an interesting article in an old MAN about a hop up kit
    available for the G-23.  The performance figures quoted were 9000 RPM
    with a Dynathrust 18x8 prop at 102 db.  These are the type of reviews
    that I find very helpful!
    
    On another note, I called a new outfit, Leroy Enterprises, that is
    offering a 2-meter towplane with gelcoated fiberglass fuselage,
    foam/obechi wings, twin rudder for $99.
    
    I am now debating about building this instead of the Senior Telemaster
    for my towplane.  The time to build is the gating factor.
    
    
    Thanks,
    
    Jim
1558.58Towplane orderedUNYEM::BLUMJThu Jun 16 1994 12:1926
    Due to a serious lack of time I have ordered a "Major" towplane
    from Leroy Enterprises instead of trying to build a Senior Telemaster.
    I may build the ST later, if the Major does not work well. 
    
    The Major comes with a gelcoated fiberglass fuselage and foam wings
    which you must sheet with obechi(provided).  It also incorporates twin
    rudders to make towing gliders easier.
    
    The basic specifications are:
    
    Major basic kit - $99($15 shipping in USA)
    wingspan - 2 meters
    length - 1.4 meters
    motor - .60 - 1.08
    airfoil - NACA 23015
    wing area - .6 sq. meter(931 sq. in.)
    weight - approx. 10 lbs.
    
    I am planning to use an O.S. 1.08 at this point.
    
    Still need to get another radio and flight box.  The investment will be
    quite substantial, since I own no glow fuel stuff at this time.
    
    Looking forward to my first power plane!
    
    
1558.59Major kit receivedUNYEM::BLUMJThu Jun 30 1994 17:2215
    I received the "Major" towplane from Leroy enterprises Tuesday.
    
    It came with fiberglass fuselage, white foam wings with obechi sheeting
    cut to size, fiberglass landing gear, precut stab and rudders(balsa),
    plus the balsa for the wing leading edge, and ply firewall.
    
    All-in-all not bad for $99.
    
    To an experienced power builder this plane would be in the air very
    quickly.
    
    I am definitely sold on foam and fiberglass, it is tough and easy to
    repair.
    
    Hope it flies well.
1558.60Major towplane flys35989::BLUMJTue Oct 04 1994 11:3414
    Well the "MAJOR" towplane flew this weekend for the first time.  I am
    very pleased with the plane and especially pleased with the O.S. 1.08.
    The plane is a bit heavy(I built it like an ARMY tank!) but has a very
    gentle stall and superb ground handling.  All who saw it fly were
    impressed.  The O.S. 1.08 is a powerhouse, the vertical on this 11 lb.
    airplane is great!  Hopefully we will test it's towing capability this
    weekend with some 1/4 scale gliders.
    
    I never thought I would own a glow powered plane but here I am - never
    say never!
    
    Regards,
    
    Jim
1558.61Sounds like a new convertMKOTS3::MARRONEWed Oct 05 1994 13:2118
    Jim, welcome to the "glo-glop" fraternaty!  I've always read your
    comments about clean glider/electric airframe designs and how they fly so 
    well, and your general discontent with all those pilots who fly draggy,
    overpowered, not-high-tech designs, and wondered how you could ever find
    any pleasure flying ignition-powered aircraft.  I hope that your new 
    experience has been a good one.  I'd also welcome your comparison of the
    two types of flying and the pros/cons of each.
    
    I fly only glo-powered planes, and have not yet felt the pull to get
    into gliders.  I will say that you've made a very strong case for the
    glider side of the hobby, and I would consider you this conference's 
    best advocate.  Like you, I may some day cross over and tackle a new 
    challange, and when I do, I will always feel the "Jim Blum influence".
    
    Regards,
    Joe
    
     
1558.62We need more converts... both ways56821::WALTERWed Oct 05 1994 14:1410
    Y'know, I've always wondered why someone would want to stick to just
    one aspect of the hobby. I fly both gliders and power regularly, and 
    only lack of spare time keeps me from following Dan Weier into choppers
    (a waste of talent there... with a little training Dan could be a
    dynamite glider guider!). My personal opinion is that flying both
    gliders and power makes you a better pilot. Skills from one discipline
    carry over into the other. 
    
    Dave
    
1558.63MR3MI1::JCAVANAGHJim Cavanagh MRO3-3/N20 297-4590Wed Oct 05 1994 14:4816
>    Y'know, I've always wondered why someone would want to stick to just
>    one aspect of the hobby.     



  Gee Dave, don't you remember *my* last outing with a glider at the Acton
field???  My 2x4 turned into a dragonfly!  :^)  I think I'll stick with
glow-glop!  :^)

  Okay...I'll admit that I would like to get an electric glider.  I don't 
have the desire to fight with a high-start so an electric would be nice.
I'll just put in on the list of things-to-build and it should get done in 
10 or 20 years!  :^)


                 Jim
1558.64I like it allSNAX::SMITHI FEEL THE NEEDWed Oct 05 1994 15:4415
    Like Dave, I enjoy all aspects of the hobby. The only problem is,
    it's EXPENSIVE. Right now, I'm set to fly glider (2 meter and open),
    funfly (Goblin), pattern (LA1), and just horsing around (semetrical
    wing trainer and Gremlin).
    
    That's 6 airworthy aircraft each with it's own RX, RX battery, servo's
    motor's etc. I'd love to build an HLG, but don't have the money to put 
    into it. I'd love to get a chopper, but dont' have the money to put into 
    it. I'd love to get into scale, but...............
    
    Oh well, maybe someday I'll win the lottery and then I'll build my own
    flying site. There will be a big hill totally cleared on all sides for
    sloping. Bottom of the hill will be a flying site for
    power/glider/chopper. Paved runway, built in winches, and for the
    chopper guys, an onsite PARTS STORE. 8^)
1558.65I like it, I like it!35989::BLUMJWed Oct 05 1994 15:5833
    I have to agree with Dave Walter that flying power will help your
    glider flying and I think vice versa is also true. In fact I would
    recommend that perspective glider enthusiasts come into the hobby
    via a glo trainer if possible.  The stick time you can get with a glow
    plane will speed up the learning curve dramatically, the years I spent
    flying off of high starts resulted in very little "air time" with much
    more time being spent chasing the high start.
    
    I have never meant to convey that I was against power planes in my
    support of electric and gliders.  I have always liked high performance
    power planes flown competently.  I enjoy the challenges of R/C and am
    not content to sit back, which is why I really like gliders - just
    staying up is a challenge!
    
    I feel that glow powered trainers are necessary for learning and when I
    have mastered the "Major" towplane I will probably build either a scale
    glo plane or a pattern type plane.  I still am a little nervous when
    adjusting the needle valve on the O.S. 1.08 with APC meat grinder
    spinning furiously, though!  I have received a lot of great help in
    this first power plane from club members and that has been much
    appreciated.
    
    I hope to be attending some scale meets next year as both a tow pilot
    of a scale tow plane and a glider pilot of a scale glider - not
    simultaneously of course!  An immaculate 1/4 scale scale glider being
    aerotowed behind a 1/4 scale cub really is cool!
    
    Glad I got into IC aircraft, it has been a lot of fun(hell I'll be into
    my 3rd gallon of fuel by this weekend!).  
    
    Regards,
    
    Jim  
1558.66Just use common sense!MR3MI1::JCAVANAGHJim Cavanagh MRO3-3/N20 297-4590Wed Oct 05 1994 16:5439
>>    I still am a little nervous when
>>    adjusting the needle valve on the O.S. 1.08 with APC meat grinder
>>    spinning furiously, though! 


  Welcome to the club!  I've been adjusting needle valves for 5 years now and
I *still* get nervous with my fingers that close the prop!

  Some ways to *reduce* the danger are:

       o  NEVER adjust the needle valve from the front of the plane!!!  ALWAYS
          ALWAYS ALWAYS make sure that your behind the prop!  I've seen too
          many people get bitten, and seen too many people with scars up their
          arms to EVER consider reaching over or around the prop to do 
          adjustments or remove the ni-starter.

       o  Make sure the plane is secure!  Have someone hold the plane or stake
          it down so it can't jump forward or backward (backfire resulting in
          a backwards spinning prop).  You also have to be a bit careful when
          you or someone else is holding the plane and the engine suddenly sags.
          The force being used to restrain the plane can pull it backwards, 
          forcing your fingers into the prop!

     The bigger the engine the more dangerous it is!  I've gotten my knuckles
smacked a few times...but I don't have any missing fingers or scars!

  I also try and avoid hand starting my engines whenever possible.



  An ounce of common sense can save a finger or hand!



              Have fun!!!!!!


                  Jim

1558.67I soloed!35989::BLUMJMon Oct 10 1994 14:2615
    Well I "soloed" this weekend in 15-20 mph wind.  The wind is actually
    an advantage to slowing this heavy beast down on final.  Still a 
    little shaky but coming along.  Never realized what a bad left thumb
    I have - too many years of rudder/elevator flying only.
    
    I am definitely a ways off from being a tow pilot, however.  Next year
    maybe!
    
    I am glad I learned on a tail dragger and if I can land this 11 lb
    plane, I should have a leg up on landing scale and pattern designs
    in the future.
    
    The power flying has improved my landing skills dramatically.  My
    glider landings are much improved as a result!  Hoping for more
    nice weather and flying fun!