PL-12 Airtruck
 

I decided to attemt my first scratch build. I have grown tired of the selection of arf's, they are not always to my taste, or everyone else has one. So here goes.
After looking around for what I wanted to have I found there usually were no kits available. One of the planes I have always liked is the PL-12 Airtruk. After searching for plans the only one I could find were from New Zealand Aero Products. That company has no web site and may have gone out of buisness. So I posted on here for someone with a set of plans and found one person that had a set. I wish I could give him credit but I no longer have his info. He was nice enough to lend me his plans so I could have them copied. When they arrived I was suprised at the size of them, so I had them reduced to 75% of original and it now will have a 86" span. I haven't decided on an engine yet but would like to go gas. Maybe a 20cc - 30cc. As I said this is my first try at scratch building but I have researched this for almost a year so I feel confident in trying. I will post as I go and please fell free to coment,good or bad about my build.

RE: PL-12 Airtruck
 

First thing I tried was the lower wing. I cut the ribs out of the plans and glued them to a piece of 3/16 poplar wood. Then drilled thru it and added a second peice and bolted them together. They were then cut out of the poplar and sanded to shape. I them unbolted them and sandwiched balsa sheets sheets between the two peices. The stack was then sanded to mathch the poplar templates. The upper wing ribs were done the same way. I then laed out the pieces per the plans and here is what I ended up with. Once every is all built it will get fiberglassed and painted.

RE: PL-12 Airtruck
 

After some sanding and shaping here is the lwer wing. The hole in the center is for the seed hopper the goes from the top to bottom of the fusalage. There will be a hinged door across it that will be servo activated.

RE: PL-12 Airtruck
 

Hi

I found a kit for this plane, FYI: http://store.laser-design-services.c...roducts_id=210


Vince

RE: PL-12 Airtruck
 

I have read his build, but did not know he was offering a kit.

RE: PL-12 Airtruck
 

Everything is coming along pretty well. The original plans called for the flat plywood spar to bolt the wing halves together. I like using a wing tube. Finding a tube was easy enough but the tube it goes into was another story. Anyone I talked to said you cant get one or I would have to make one. After some searching on the web I found a company called TNT Landing gear ( http://www.tntlandinggear.com ) they can supply both. I called them and got a 1" wing tube and the phenolic outer tube sent. It is a very nice peice and I am very happy with it.
The rudders and elevators are coming along and I have started cutting out the parts for the tail booms also. The original plans call for the tail booms to have 4 stringers and 5 ribs. At one end the booms are 1 5/8" diameter, they tapper down to only 1". I still have to add two flex tubes for the rudder and elevator on each side. That doesn't leave much room at the smallest rib for the square stringers and flex tubes. 1" rib minus 1/4 on each side for the stringers and 3/16 x 2 for the flex tubes leaves me with 1/8" of wood to support the tail. So I am going to use 1/4" x 1/8" for the stringers to make some room and then put sheet balsa from one end to the other as a spar of sorts to give more strenghth hopfully.

RE: PL-12 Airtruck
 

Great poject! A truly unique plane. I'm subscribed and looking forward to your posts.

I think if you bond the flex tubes into the ribs (formers) they will become part of the rib and contibute to the strength of them. It could add a little stiffness to the whole boom, too.

Nice work!

RE: PL-12 Airtruck
 

<div><span style="font-size: 9pt; line-height: 115%;">Looks like you are doing goodcodydaniels. I love scratch building. It is even more enjoyable scratch building your own design or at least highly modified plans. This plane looks like it might have some challenge to. That is a good thing to my way of thinking. Keep us posted.</span><span style="font-size: 9pt; line-height: 115%;">

<span style="background-position: initial initial; background-repeat: initial initial;">A very different looking plane for sure.</span>

<span style="background-position: initial initial; background-repeat: initial initial;">I had to google the plane acourse. Found a good video that explanes the looks a lot.</span>
<span style="background-position: initial initial; background-repeat: initial initial;">http://www.youtube.com/watch?v=v-asgD0s5Ss</span>

<span style="background-position: initial initial; background-repeat: initial initial;">Ken</span></span></div>

RE: PL-12 Airtruck
 

I have seen that film several times, thanks.

I did find these photos very interesting that you could by a full size plane and have it shipped in boxxes to your house. Imagine the propblems you would have now over here if you tried that.

RE: PL-12 Airtruck
 

It's a giant ARF!http://www.rcuniverse.com/forum/js/f...sn/biggrin.gif
That is cool

Ken

RE: PL-12 Airtruck
 

Priceless!! http://www.rcuniverse.com/forum/js/f...ey/msn/lol.gif

RE: PL-12 Airtruck
 

Not to much progress lately. I was having problems trying to get my balsa to bend into a small enough tube to cover the tail booms. I was looking around the house for a large enough bucket to let the wood saok for a while and found the perfect container. My juccuzzi, nice warm water. I left it to soak for a while then wraped them arouind a broom handle and let them dry for couple of days.

RE: PL-12 Airtruck
 

Hi

You could have planked it with strips of balsa! Then sand to shape.


Vince

RE: PL-12 Airtruck
 

codydaniels How thick are the tail boom sheeting.

Ken<br type="_moz" />

RE: PL-12 Airtruck
 

I had thought about planking them but they are 1" in diameter at the tail end and 1 3/8" at the wing end. It seems to me that planking would have been more efort than it is worth and would not be as strong as if it is wraped. I ended up covering each side of the boom with one piece per side.

The balsa I used is the thinest I could get at the hobby store, 1/16". I tried with 3/32" but it kept spliting. Once it is glassed it should be pretty strong with the I beam down it's center.

RE: PL-12 Airtruck
 

So I haven't worked on it as much as I would like lately but here is my progress from last night and today. Servo trays are made and installed. Lower half of wing is sheeted. Still have the other wing to do.
The servos were a hassle because of the limited room in the wing. A standard servo will hang out the bottom and top but if you lay it on its side it fits. When you do that there isn't enough space between the ribs to get a clevis on and off easily and since the control arms and rods are all hiden I need to get to the clevises. After seaching around I found Hitec HS77BB's they are a perfect fit. They rated at 61.1 oz/in of torque at 4.8V; 76.3 oz/in at 6V Speed: 0.18sec/60deg at 4.8V with no load; 0.14sec/60deg at 6V with no load. Basicly they are retract servos without the end limiters on them. And they only measure, Length: 1.73" Width: 0.90" Height: 0.98" so they fit in real nice without being overly expensive.

RE: PL-12 Airtruck
 

Another week gone by. I finished sheeting one wing and did most of the major sanding on it. Still have to add the end cap. Started the fillet between the tail boom and control surfaces. The other wing has been sheeted on the bottom and I started the fusalage lower half. My engine showed up, an RCV90-SP that came from a RCU member,spitfire MK. IX. Many thanks to him.

RE: PL-12 Airtruck
 

codydaniels Looking good lots of progress.

<span style="font-family: Verdana, Arial; font-size: 13.333333015441895px; background-color: rgb(251, 252, 255);">RCV90-SP Boy that suprised mehttp://www.rcuniverse.com/forum/js/f...sn/biggrin.gifcool.

Ken<br type="_moz" /></span>

RE: PL-12 Airtruck
 

OK, ist's been a couple weeks now and I have been working on the upper and lower halves of the fusalage. The cowl has been made of 2x3 blocks but is not glued to the fuse, when I get a little further along I will separate the two and make that look a bit better than it does now. This week I will de working on getting the wing incedence set.

RE: PL-12 Airtruck
 

I could not get all the pictures on at once, so here are the last ones of the past weeks.

RE: PL-12 Airtruck
 

Got the wings set today and got my first real look at what it's going to look like. It measures 85 3/4" tip to tip. I still have to make tthe top of the fuse. And set the elevators.

RE: PL-12 Airtruck
 

It has been a while since my last posting,work is progressing slowly. Mounted the engine and got the thrust line set. Every plane I have had has had a downward thrust. The plans call for up thrust on this one and no side thrust, kind of strange but that's what it calls for. I did not think the roof line looked correct so I spent some time making that look more scale like. Got the cowl sanded to shape and located with dowles

RE: PL-12 Airtruck
 

I have also started glassing it, so far just one wing and the associated control surfaces. The other wing has been glassed on one side. I am using 1/2oz cloth and polyester resin. The nice thing about that over others is you don't have to sand it to top coat it. just sand the nubs and trash out of it and topcoat with polyester gel coat. I know this is not a common finish to our planes. The gel can be sprayed extremely thick. This allows you to sand a majority of it back off to make it nice and smooth, filling in the bad spots at the same time. I believe there is an advantage over regular primer as a filler since gel coat is catalyzed it will not shrink much once it is cured where lacquer primer will shrink for weeks to months later possibly causing the weave to show. Corvettes are gel coated and they look pretty good. I have not weighed anything but a quart of gel seems to weigh less that a quart of primer. I will try to weigh the other wing before and after gel coat.

RE: PL-12 Airtruck
 

<div><span style="font-size: 9pt; line-height: 115%;">Realy looking good. Progressing nicely.</span> I find that most of my planes progress in bits and pieces and spurts. Heck I have a plane that I have been at for well over a year.</div><div></div><div><span style="font-size: 9pt; line-height: 115%;">Ken</span></div>

RE: PL-12 Airtruck
 

Today I was able to get everything glassed. Now,lots of sanding and priming.Fun fun fun.

Should I go for the new and shiny look, or the old and used?