PT 19

[TEAJR66]

This wasn't supposed to be about the plane. The PT 19 was chosen as the subject to demonstrate SketchUp techniques in my "to be" second article. The plane came out amazing, but it still wasn't supposed to be about the plane. In capture and editing the video segments for the article, I screwed up and ended up with not too much usable stuff for the article. Since I was left with the plane, I decided to make it about the plane.

The original plans for this model were found on the Outer Zone web site.

FT Power Pack "B" and "C".
2200mAh 3S.
AUW? no scale available.

Here is the plane.



The first version did not have a tapered nose. I wanted to save that for the "making adjustments to existing plans" part of the article. So, after it flew, I adjusted the plans and made the tapered nose.

This is what the final product looked like.













Here is a flight video.

Here are the plans if anyone is interested.

View attachment PT 19 Foam Plans V1.1.pdf

 

[earthsciteach]

I do like the looks of your model, Tommy. Thanks for the plans! It is on my build list when I get through some of this perpetual backlog.

 

[T-Richard]

It looks great! looks and it seems to fly a lot like the FT spitfire. what's your wingspan?

 

[dgrigor02]

Wingspan of parts flat before the dihedral measure 58 inch.

By far the largest I've attempted. Parts are cut out. Will start assembly tomorrow and will post when I'm done. I'm going to build two, full size and a 60% ( turns out just a tad over 800mm ).

 

[TEAJR66]

Here are the plans for a 43" wing span. I have not built this one. It wasn't designed to be swappable. At this size I like to use the FT Elements Simple Firewall (the same one from the FT 22). Just glue it to the underside of the top plate.

View attachment PT 19 43 INCH.pdf

Part of the article was supposed to include scaling the foam plans after the plane was modeled. These plans have the slots and tabs correct and the wing panels were adjusted for thickness.

There will be plans for a 28" span also. I still need to clean them up. It will have a completely under cambered wing and should fly on the "A" power pack, like the other 28" span models I have built.

 

[T-Richard]

I like the 58 inch version...... may make the build list sooner rather than later

 

[TooJung2Die]

Really nice looking airplane. I have fond memories of flying the Cox U-control PT19 as a kid. I think I'll build the A power pack size after I wear out another Tiny Trainer. Good job!

Jon

 

[dgrigor02]

Wing and tail are done. Working on the fuselage now. Hoping to be in the air tomorrow.

 

[earthsciteach]

This forum needs a "like" button.

Fred???

 

[T-Richard]

Wing and tail are done. Working on the fuselage now. Hoping to be in the air tomorrow.

looking forward to seeing this one completed! I like the size and look of this one and I am happy you went with the scale color theme

 

[TEAJR66]

Wing and tail are done. Working on the fuselage now. Hoping to be in the air tomorrow.

Wow! That is looking very nice. I am also digging on that color scheme. I like what you did there. I can't wait to see it fly.

Will you try landing gear? I did not have thick enough wire to try.

Here are the original plans, incase you needed to see placement.

View attachment PT-19_Electric_58in.pdf

 

[themajik1]

Good job Tommy! I do like that plane a lot. May have to build one!

 

[dgrigor02]

Tommy, I couldn't really tell what the BBQ skewer right at the wing are for. There is a doubler there was that intended to make the wing removable or for the landing gear ? If for removable wing I couldn't figure out how to get it lined up so I made the wing permanent.

 

[TEAJR66]

It was for a removable wing. Once the fuselage was built, the skewers went through the doublers. Rubber bands under the wing to the skewers.

I only made it that way because of the span. If it fits for transport, then it is no big deal.

I did not try to work out the landing gear because I had no wire available.

 

[dgrigor02]

It's a rainy day so likely won't get to fly today but here it is all wired up except the ailrons aren't cut out yet and needs the front deck trimmed once power pod is seated.

Total model weight minus electronics is 509grams. Total flying weight ( Altitude Hobbies beef package + 2200mh battery ) is 823grams.

The back turtle deck was 1/2" short for mine so I had to cut another slightly longer. Other than that, everything else the plans worked great.

Color is all just packing tape from tapebrothers. Just cut it into thinner strips for the tail.

Took me 5 sheets but it more carefully planned out you can probably squeeze it in 4 or 4+ a few scraps. The fuselage was longer than 1 sheet so had to tape and glue two together. I've never built one before that needed to be joined.

 

[TEAJR66]

Great job. Looks nice. I like the color.

I tried to lay it out on four sheets, but I always came up a little short so I spread it out over five sheets when I did the plans. The fuselage is pretty big. I played around with fuselage joining techniques and, for me, the best was joining the boards then cutting the fuse as one. In other models, any little variation in cuts from one half of the fuse to the other, made the joining ugly. With the sheets together and cut as one, the deviations are consistent.

I'm glad you got the weight. I had no scale available. Here is the wing area 3.185518 ft² if someone wants to calculate the wing loading.

Looks like you went with the servos internal. I had them at 15" from the hinge line to accommodate FT push rods. If you were to use anything longer, it would be better to mount the servo's further forward. With the "C" power pack, I had to put the battery under the pod all the way forward to keep from adding dead weight.

I will make an adjustment to the turtle decking. Too long would be better than too short. Did the blue crease lines help with alignment for the turtle deck? They worked great for me, on this one and another model also.

can't wait to see the flight video. That was a pretty quick build.

 

[dgrigor02]

Yes, I joined two sheets together before cutting the fuselage. Glad you confirmed that was good.

I put the servos exactly where you had the marks only on the turtle deck instead. This way the formers helped with rod flex.

It for sure helped with the world series game 1 goes 14 innnings to get it mostly finished.

I didn't use the markings becuase the tape covered them on the turtle deck, just by feel tried to center as best as possible. Lots of clear tape, didn't want permanent just yet incase I do need to change something.

I don't know the best way to do the wing, I did the sides first then the middle fold over last. Didn't test fit as much as I should have and was hard to do once glued, added a bit too much force and delaminated some on the curves.

 

[TEAJR66]

I did the wing that way also. Did the end panels then added the center section. The spar is a little flimsy during construction. If I did it over, the center would go in first, do some test fitting into the fuselage, then add the end panels, matching them to the center section as I went.

I like your method of putting the servos in the top plate and guiding the rods through the formers. Brilliant! In that case, they would go well in the rear cockpit hole and covered by a pilot figure.

 

[dgrigor02]

I did forget to mention all minor stuff. All the models I've done the spar goes out all the way where the bottom flat part of the wing ends. I placed the servos where your spar ended but then added another 8" ones to reach the end. If nothing else it helped to keep the top crease parallel while gluing the wing together.

One the smaller versions do you also plan to do the spar the same way where it is 1 piece for the dihedral ? Smaller it gets the more tricky that may be. I do plan to do a 800mm ish size ( 60% = 34in / 840mm ) as I have lots of 2204 motors that should do well.

 

[Tench745]

FYI, wing loading works out to about 9oz/sqft with a cubic wing loading of 5.1.
This should definitely should be a floater, and it looks so good.
On my Jenny build I put the elevator and rudder servos in the aft cockpit which makes them easy to get to if they die. A small piece of poster board just friction fits in on top of them if I want to hide them.