Sport PT-19 (Speed 400 Outrunner)

[PipesCS]

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.

[PipesCS]

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.

[PipesCS]

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.

[PipesCS]

This is a better shot of the battery compartment and the motor hatch prior to thinning it down.

[PipesCS]

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

[PipesCS]

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.

[PipesCS]

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

[PipesCS]

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.

[PipesCS]

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.

[cpc]

Is a copy of the PDF still available? A dxf would also work.

Thanks

Charlie

[PipesCS]

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.

[PipesCS]

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.

[cpc]

Like the new fuselage. Sent you a PM.

Also need info on Top Notch

Thanks

Charlie
Columbia, pa

[PipesCS]

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.

[PipesCS]

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.

[PipesCS]

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

[PipesCS]

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.

[PipesCS]

Had a little trouble getting these to upload

As I say the newer ones are wider to take the screws and straps

[PipesCS]

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

[PipesCS]

They build much faster than the original. May not be as strong but I have yet to find the need for the extra strength

[PipesCS]

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.

[PipesCS]

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.

[PipesCS]

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.

[PipesCS]

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)

[PipesCS]

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.

[PipesCS]

I am not getting too much time in the shop and as you can tell my kids are trashing the shop anyway with a summer art class

The old reliable PT 19 number 44 is almost overhauled. It only needs a set of new ailerons put on and it will be ready to go. It has been in the air since Dec of 06 and has well over a hundred flights.

Number 77 is getting there. Next step is to put in the wing bolts, detail out the rudder stripes and hang the tailfeathers and tail wheel. Motor has already be fitted and it and the speed control will slip back in as soon as I cut out the monocoat from the cooling holes

I have been flying an ARF at lunch the last few days and must admit I miss number 44 as it much more fun to fly.

These photos also show the increase in Dihedral in the new wing.

[PipesCS]

Starting to get number 77 ready to fly. did a taxi check today to check out the radio

Found a bad rudder servo and will need to replace it later in the week.

Just down to the detailing now.

[PipesCS]

Weighed both models and found they weigh within a half oz of each other:)

The models without batteries are twenty and a half oz for the prototype and twenty and three quarters for the new one. The batteries will push them to twenty five:wave:

[PipesCS]

Getting it ready for the final photos

Managed to get both into flying trim today and am just going over a few details.

[PipesCS]

Well this is done and its time to get back to the covering on the Model Y Gee Bee.

Once again if anyone whants a free copy of the plans drop me a line and I will send a PDF copy that you can have printed at your local Kinkos

The short kit is also available from John Valentine at Top Notch Products out of Tenn.

[PipesCS]

Well today was overcast and not a good day for photos but a good day to fly a first flight due to no wind and not scorching hot.

I finally get to say "It flew right off the building board.":)

Increasing the dehidral seems to have made it a little better at slow speeds

The longer nose with the motor being more forward helped with the CG placement.

I would say I was completely done but need to make a few changes to the parts cut order that CPC has recommended having started his PT-19

The really clear sunny shot is the Prototype flying just before I recovered the wing.

The photo of the two stacked on top of each other is why I like this size model. I flew both of them at lunch today and still went back to work.:(

[PipesCS]

Talking with a fellow modelers I pulled out the drawings and moded it them more time. The wing leading and trailing edges are now part of the laser cut short kit. John has added in the sheet stock and a few more items for the fuselage build.

Very quickly John is taking it from a short kit to the full blown thing.

Here are some photos of the proof model. (I now own four) It shows the aileron servos being moved to the outer wing instead of in the fuselage and the tabbed and slotted leading and trailing edges. Also shown is the vertical grain shear webbing that is also now part of the laser cut kit. They droped right in place between the spars. Total parts in the short kit now are at over 190.

The panel is ready to sand and shape the leading and trailing edge along with the wingtip.

Total time to build the wing panel was less than 45 min.