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Thread: Sport PT-19 (Speed 400 Outrunner)

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  1. Sport PT-19 (Speed 400 Outrunner) 
    #1
    Join Date
    01-25-2007
    Location
    Lester Alabama, USA
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    476
    I started this thread in the wrong place and decided to put it here.

    This years project is a PT-19 electric that I worked up the plans from a friends gas .10 version. I wanted a model that was small enough to sit in the seat of my pickup put together and fly on the way home from work. (40 inch wingspan)

    I had Top Notch Products in Tennessee cut the short kit (around 52 Parts) which came to around $31.00 after shipping and handling. I tried to bring the model to a point that a modeler who had the tools and experiance to build an ARF could build this in about a week

    Total weight with a 450 E Flite Outrunner/20 amp speed control/1650 ma 3cell li poly was 23 oz. it is a floater with the capability of speed on call

    It is turning into an excellent tail dragger trainer and second plane.

    This is the first prototype on the plans and the second kit cut.

    The model is what was called stick and tissue construction in the old days and is much lighter that a lot of lite ply construction while still being plenty strong.
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  2.  
    #2
    Join Date
    01-25-2007
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    Lester Alabama, USA
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    I forgot to mention I am not a modeler who is in this for the money

    I would be more than glad to convert my drawings on this and the Gee Bee D Model to a PDF format and E mail them to anyone who wishes to go to Kinkos and make copies

    John at Top Notch Products would be more than glad to cut and ship to anyone as I make no claim on the work exept that you enjoy it.
     

  3.  
    #3
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    01-25-2007
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    Lester Alabama, USA
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    One of the changes I made in the conversion of the original design was to make the cowl part of the fuselage so that the motor could be installed with two screws thru the nose block. I also made the cockpit a removable hatch(made up of 5 pieces in the short kit) to give easy access to the battery compartment. The motor and and battery hatch are held down by 1/8" rare earth magnets from Radio Shack.
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  4.  
    #4
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    01-25-2007
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    Lester Alabama, USA
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    476
    This is a better shot of the battery compartment and the motor hatch prior to thinning it down.
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  5.  
    #5
    Join Date
    01-25-2007
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    Lester Alabama, USA
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    Spoke with a print shop on cost to reproduce plans from a PDF should anyone wish a set. The price varies greatly. I shop I deal with in MD carges 29 cents per square foot of the final print where Kinkos gets .75
     

  6.  
    #6
    Join Date
    01-25-2007
    Location
    Lester Alabama, USA
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    476
    As I said at the start this is a sport model to be built with basicly an Exacto-knife, sanding block, straight edge, glue, and covering tools.

    This is the first prototype wing after joining the two panels with 2 ply doublers. I have started the 3/32" shear webbing with is cut to fit between the upper and lower spars. (If you look close you will see I forgot that the grain should run verticle. I did go back and replace it.

    The leading and trailing edge is made from standard square balso and sanded to shape.
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  7.  
    #7
    Join Date
    01-25-2007
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    Lester Alabama, USA
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    Although I am still working this model on the second prototype of this model I am getting distracted by the start of the D model Gee Bee.

    The Gee Bee uses the same wing with different tips and a larger fuselage. It is powered by a larger motor so the battery compartment has been enlarged to take a 2100ma.

    One note

    I have figured out how to convert my CAD drawings to a PDF and should be able to E mail them to any one that would like a "free" set. they are about 3 x 5 foot and kinkos can print the file full size for about .75 cents a sq ft.

    The photo shows the 2nd prototype PT 19 on the left of the Gee Bee
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  8.  
    #8
    Join Date
    01-25-2007
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    Lester Alabama, USA
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    One last note on this project.

    The short kit can be bought from Top Notch Products for around 31 Dollars.

    I am doing the clean up on the drawings and should be able to email a printable copy to anyone interested by the end of the month

    As part of the testing for the Gee Bee I went ahead and added lead till the model weighed 30oz and still had good flights with it limiting the motor to 11.5 amps max on static runs. Managed 10 min flights with no problems.
     

  9.  
    #9
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    01-25-2007
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    Lester Alabama, USA
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    I have kind of let this thread fall by the wayside as not too many people even seem to look at it. But for those that have and continue to, I would like to say this PT 19 is the best airplane in my stable. The original design by Bob Somers in Maryland and My Electric Conversion continue to Fly and Fly well.

    I loaded mine up with lead to bring it up to 34 oz as that is the weight of my Gee Bee. I warmed up with the PT to be ready to test the Gee Bee.

    With its wide gear and long tail it is a great flier for me at lunch. I leave it in the truck seat for weeks so the covering looks rought due to the heat but I get to the field at lunch fly two flights and go back to work.

    I keep my batteries in a thermal lunch pouch with icepacks to keep them cool in the truck during the summer to protect them from the heat. These were taken when I had a photographer out to shoot the Gee Bee Test hop.
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  10.  
    #10
    Join Date
    07-16-2008
    Location
    Columbia, Pa
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    2
    Is a copy of the PDF still available? A dxf would also work.

    Thanks

    Charlie
     

  11. The PT 19 Re-Do 
    #11
    Join Date
    01-25-2007
    Location
    Lester Alabama, USA
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    The PT 19 was my first effort at and electric and a very small short kit was worked up for me by Top Notch Products in Tenn.

    I never really did to much after the first two kits were cut except fly it. The original has been flown well over a hundred flights now and has been used as a test bird for some of my other projects.

    The construction is dated to say the least. It was a gas model originally that weighed almost 40 oz with the electric weighing in less than two pounds.

    A few people have shown interest in it and I decided to re do it to make it easer to build using the newer concepts that laser cutting offered.

    You can still cut all the parts on your own if you want to as they are on the plans.

    The plans are still for free should you want to send me an email thru the messaging service on this site. If you order the short kit from John at Top Notch products he will also print the plans for you. I believe he is cheaper than kinkos.

    The biggest change was to take the fuselage from a square stick and tissue design to a sheetwood rear fuselage. This gave me the chance to round the corners to make it a little more pleasing to the eye. By moving the aileron servos out into the wing it gave me the room to mount the servos upright in the battery compartment. This allowed straighter push rod runs to the tail.

    The new fuselage came out only three quarter oz heavier than the stick built and is not only much stronger, it was built in about an hour of my time.
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  12. Tail and wingtip changes 
    #12
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    01-25-2007
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    Lester Alabama, USA
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    The original tail and wingtips were made up of balsa laminations formed over plywood formers that john put in the kit.

    Having built a Gee Bee by Mad Rob I decided to try his method of construction. I don't think it is as strong but having over a hundred flights on the PT I don't feel you need it.

    The new method is simply gluing up the cut pieces over the plans (Use Wax paper)

    I built the tail feathers in less than thirty min. All parts of the tail and tips are now in the short kit, including the diagnal bracing which has the beveled ends cut. They fit perfect.
    Attached Images
     

  13.  
    #13
    Join Date
    07-16-2008
    Location
    Columbia, Pa
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    2
    Like the new fuselage. Sent you a PM.

    Also need info on Top Notch

    Thanks

    Charlie
    Columbia, pa
     

  14.  
    #14
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    01-25-2007
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    Lester Alabama, USA
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    One other change I made was to lengthen the nose to help balance the extra weight added to the tail.

    This is one of the original stick built fuselage next to the new one.
    Attached Images
     

  15. Servo mounts 
    #15
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    01-25-2007
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    Lester Alabama, USA
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    The original design had the aileron servo in the wing center section which really cluttered up the wing mounting area.

    It worked so well on the Model D Gee Bee to move them out to the wing that I did it on this one also. I am using the Hitech 55 series.
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  16. Landing gear blocks. 
    #16
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    01-25-2007
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    Lester Alabama, USA
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    I realized on this thread I missed a lot as I felt no one was interested. Now that I am getting interest I need to go back and show some of the things that are not too common.

    The landing gear is made up of the laser cut pieces to do away with the need to rip a slot in a small landing gear block. You simply lay up the pieces to make the blocks
     

  17.  
    #17
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    01-25-2007
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    Lester Alabama, USA
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    These are photos of the original blocks that were really too narrow

    On the later models I added wider areas for the screws and straps to anchor the wire.
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  18.  
    #18
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    01-25-2007
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    Lester Alabama, USA
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    Had a little trouble getting these to upload

    As I say the newer ones are wider to take the screws and straps
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  19.  
    #19
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    01-25-2007
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    Lester Alabama, USA
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    Gave up on trying to load the old photos that show the gear blocks. Finished the sheer webbing, landing gear blocks and center wing sheeting.

    In these photos you can also see the servo mount area and the paper tube to route the servo lead through
    Attached Images
     

  20. New tips 
    #20
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    01-25-2007
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    Lester Alabama, USA
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    They build much faster than the original. May not be as strong but I have yet to find the need for the extra strength
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  21.  
    #21
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    01-25-2007
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    Lester Alabama, USA
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    Finished building the wing tonight.

    All the major parts are now assembled with the next step to sand every thing to its finished shape, install the pushrod tubes in the fuselage. put on the covering and finish up.
     

  22.  
    #22
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    01-25-2007
    Location
    Lester Alabama, USA
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    Thought I would add a few more of the early photos showing the newer construction.

    The lower nose block is shaped then hollowed out leaving a wall thickness of around 1/4 inch. The lower block is epoxied between the nose and F-2 to carry some of the stress from the motor being screwed to to the front plate.

    The blocks are built up from sheet stock.

    after gluing up the nose blocks and glueing them to the fuselage I use a coarse grit belt sander to rough shape the plywood nose plate.
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  23.  
    #23
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    01-25-2007
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    Lester Alabama, USA
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    Covered the wing today and put on the decals. Need to hang the ailerons.

    Also stripped the wing to recover the original prototype as it is getting pretty rough to look at.
     

  24.  
    #24
    Join Date
    01-25-2007
    Location
    Lester Alabama, USA
    Posts
    476
    Hey CPC

    When you go to build your wing if you cannot find good hard balsa for the spars I would recommend that you go with bass wood.

    I have the same spars in my Gee Bee models and have broken 2 this year in take off incidents. (Crashes)
     

  25.  
    #25
    Join Date
    01-25-2007
    Location
    Lester Alabama, USA
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    476
    Managed to get a lot of time in the shop for me this weekend.

    Started covering the fuselage later today.

    Have to make a run to the local hobby shop tomorrow as I am out of yellow covering for the original prototype that is under going over haul. It has been in the air since Nov of 2006 and spends a lot of time in the back of my car as I fly it at lunch.

    The photo of the motor mount and battery compartment are of the prototype showing the 450 motor and a 2000ma "Common Sense RC" brand battery. It is the largest battery I use in the model. A 1600 will also fit as it is the same size exept thinner.

    I have yet to fly the prototype on a 400 E Flite motor but know it will do well as the 450 is a bit much so I prop it for only 10 amps.
    Attached Images
     

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