Shop our Airplanes Products Drone Products Sales
Thread Tools
Aug 10, 2006, 10:14 PM
Use the Force!
LBMiller5's Avatar
Build Log

150% Version of the 6mmFlyRC F-4 Phantom ParkJet


Hello to all the ParkJet fans!

It is time for a new project. As some of you may have already seen, I recently received permission from 6mmFlyRC to include their F-4 Phantom ParkJet in my enlarged ParkJet plans service. Thanks go out to CBFlyGuy for letting me have access to the CAD files for this great plane. Also, we need to give props to MJH for the original design of this plane. Way to go guys!

I really enjoyed seeing the video of the 6mmFlyRC version of this great Vietnam Era fighter on their website a few weeks ago. I knew I had to have one, but I wanted one a little bigger, so I scaled this one up 150% from the original. The plane that 6mm produces has a 38.5" fuselage length and a wingspan of 28.5 inches with 297 Sq. In. of wing area. At 150% enlargement, mine will be 57.8 inches long, and have a wingspan of 42.8 inches with 668 Sq. In. of wing area.

When I printed out the plans, they ended up being 2 sheets that are 36 x 48 inches each. To get an idea of the size of the plans, I taped them to a wall in my house and shot a photo with me standing next to them.





After I peeled the plans back off the wall, I got right to work converting BlueCor foam to F-4 Phantom pieces. One thing I noticed about these plans is that about 90% of the lines of the plane are straight. The only curved pieces are the Intake sides and the back end of the fuselage sides. Normally, when I "Kit" a plane, I carefully cut out all the templates right to the lines. Then I pin the templates onto the foam and trace the edges with a fine tip Sharpie pen. Once I have the drawings on the foam, I cut them out with an X-Acto knife.

Since this one had so many straight lines, I used a different technique that works very well. First, I cut out the templates a little oversize and pinned them down onto the foam sheet. Then I took a push-pin and poked a small hole at each corner where 2 line met. Here is one of the wing-tip panels to show you what I mean. In this photo, you can see a couple pins holding the template in place and the 4 holes that were punched at the corners.





Since I am using BlueCor, which already has about 10,000 holes per sheet, I needed a way to tell my holes from the rest. To do this, I poked the tip of my red Sharpie pen into the holes at the corners of the part. Now, when I remove the template, I will be able to see my red holes.





I repeated this process for all the parts of the plane. After I had the parts layed out, I simply took a metal straightedge and my X-Acto knife and "connectd the dots" to cut out all the parts. This way, all the cuts were perfectly straight and neat. For the few curved lines, I cut the template right to the printed line and traced the curve onto the foam with the Sharpie pen. Then I cut the curved lines free-hand with the X-Acto knife.

A couple hours later, I had gone through a little over 4 sheets of BlueCor and had cut out all the parts. Since this plane is 150% bigger than the original, I am doubling up the thickness of the foam for the wing, stabs and rudder. I cut 2 of each piece, and will laminate them together using epoxy finishing resin. So finally here is the result of all the cutting. One of my cats, "Mr. Spade", always loves to be the center of attention. I moved him out of the way 3 times to take the next picture, and every time he came back and laid down, so I figured that I would just take it with him there.





Next, I gathered up all the parts and placed them on my digital scale to see how much weight there was in foam pieces. I was hoping to keep it under 1 pound if possible.





1 pound 0.1 ounces! Just a hair over. Well actually, since I will be skinning the film off the foam on one side of the wing panels, wing-tips, Stabs and Rudders, that will save a little over an ounce of weight, so after I skin the pieces, the weight of the foam will be a little under 15 ounces. I would like to keep the finished weight of the plane down to about 3-1/2 pounds ready to fly.

So that is it for tonight, I need to get busy and start gluing all those pieces together to make me and F-4. More progress to follow shortly.

Lucien
Sign up now
to remove ads between posts
Aug 10, 2006, 10:35 PM
AA6JB
Bajora's Avatar
deleted because I somehow got an echo going in here?!
Last edited by Bajora; Aug 10, 2006 at 10:47 PM.
Aug 10, 2006, 10:36 PM
AA6JB
Bajora's Avatar
Sheesh Lucien, you don't mess around when you decide to do something.

I'll be watching this one with GREAT interest! Any idea what you'll power it with? (Realizing that is a little down the road yet!) And I'm just "up" the road from you, so maybe I can come along for the maiden!?
Aug 10, 2006, 10:43 PM
Is it SEFF yet?
reg3's Avatar
That is going to be cool. The Phantom has always been my favorite. I have been planning to build MJH's version as my first parkjet, but this size might be nice.

I wish we still had 36" wide rolls at work. I don't care much for the tiled plans. Any hope of getting a 150% pdf file that will fit on a 30" wide roll of paper?

reg3
Aug 10, 2006, 11:44 PM
Use the Force!
LBMiller5's Avatar
BARNESJONR,

I see that you are up in the San Francisco Bay area. That would put you about 500 miles North of me! Just a tad bit of a drive to come for a Maiden Flight! I hope to have it done in time for Vegas in November.

I might use one of the BM2915-5 motors I have, or possibly a new prototype that I have. I recently received some first article motors to test for a motor company. I have a 3008-14, a 3014-9 and a 3020-7 to play with, so I might use one of these as well. In the end it will depend on the finished weight. I want to be able to have at least 150 watts per pound on this one for true jet performance. Don't ask me who makes the motors, because I cannot say at this point in time.

This should be a fun plane to fly. I saw how smooth the original size flew, so I am sure that this one will be even better!

Gotta get back to building!

Lucien



reg3,

Do you have a roll plotter with user selectable plot length? If so, I can move the parts around and convert them from 36 x 48" sheets to 30 x 60" sheets and generate a PDF.
Aug 11, 2006, 05:25 AM
Is it SEFF yet?
reg3's Avatar
Quote:
Originally Posted by LBMiller5
reg3,

Do you have a roll plotter with user selectable plot length? If so, I can move the parts around and convert them from 36 x 48" sheets to 30 x 60" sheets and generate a PDF.
Yes, length is not a problem. Thanks in advance for the extra work. I look forward to following this thread.
Aug 11, 2006, 05:30 AM
AA6JB
Bajora's Avatar
I see that you are up in the San Francisco Bay area. That would put you about 500 miles North of me! Just a tad bit of a drive to come for a Maiden Flight! I hope to have it done in time for Vegas in November.

oops.... there is a San Marcos or something similar or close down by SFO, my bad

BUT, I have been waffling about going to Vegas in November. This is certainly another great reason to get me off the fence!
Aug 11, 2006, 09:59 AM
Use the Force!
LBMiller5's Avatar
Late last night I took some time and peeled off the skin on one side of each of the wing panels, wing-tip panels, elevators and rudders. I put all the pieces back up on the scale, and now the total weight of all the foam was exactly 15 ounces. I will put together a spreadsheet in Excel and try to get an estimate on the finished weight of the plane to see how close I can get.

More to come!

Lucien
Aug 12, 2006, 11:28 AM
Use the Force!
LBMiller5's Avatar

Construction Has Started!


I had to get up early today to help my sweetheart get off to an all-day seminar. After she left, I had a couple hours to kill before I went in to work, so I got a little time in on the F-4 project.

I downloaded the assembly manual from the 6mmFlyRC website, and am using it as a guide for the construction. I will need to deviate from the build sequence in a few places to fit the changes that I will be making to the plane. I started with the fuselage sides. On a plane this size, even with 24 x 48 inch foam panels, I had to splice the fuselage sides together. Here are the 2 sides after I joined them. I set a 48" metal ruler in the front so you can get an idea how large these parts really are.





In the original kit, there are a lot of 1/4 x 3/8 inch strip of foam that are used to reinforce all the corner glue joints in the kit. Since I am doing a 150% enlargement, my strips needed to be bigger. I needed strips that were 3/8 x 9/16 inch to be to the proper scale. Since I plan on sanding the corners down a fair bit, to get a good shape to the fuselage, I am going to make my strips a little bigger at 1/2 x 9/16 inch. Since I will need about 10 strips of corner stock, with the longest ones being about 4 feet long, I decided to laminate up a whole sheet of strip stock.

To make the strip stock, I cut 2 pieces of BlueCor foam that were 6 inches wide by 48 inches long. I peeled off the skin from the printed side on each piece to prep them for gluing. Then I layed both pieces on a scrap piece of cardboard out in the garage and sprayed them with contact cement. I put on a couple light coats first, to seal the foam, and then put on a finish coat to make the foam tacky. Here they are after spraying with the glue.





After the glue tacked up for a couple minutes, I stuck the two sheets together. To hold the parts firmly in place while the glue dries, I laid the pieces on the concrete floor in the garage. Then I put a 8" x 48" particle board shelf on top of the foam to act as a press. To weigh everything down, I put four 5-gallon water bottles on top of the shelf. That will put about 170 pounds of weight evenly distributed across the foam sheets. I will let them set there until I get home tonight to make sure that they dry straight and smooth.

To make the strips, I will take my Master Airscrew balsa stripper, set the depth to 9/16" and slice the strips off the sheet. Doing it this way, I will ensure that the cuts are made square, and that everything will fit together nicely.

Now, I just have to take the rest of these parts and glue them together, and I will have an F-4!





More building tonight!

Lucien
Last edited by LBMiller5; Aug 14, 2006 at 02:37 PM.
Aug 12, 2006, 04:49 PM
EB-66C Team Member
J Morgan's Avatar
Lucien,
Another great build I'm sure. FWIW, DAF and I found on the larger F-4's that the area where the tail angles in to the main body at the exhausts is the weakest part of the fuse. It could crack or actually break there. We always beefed that area up.

J
Aug 12, 2006, 05:18 PM
Use the Force!
LBMiller5's Avatar
J,

You read my mind! I was looking at that area myself this morning. That part where it necks down behind the exhausts looks VERY weak. I was planning on reinforcing the inside of the tail cone area with some 1/8" lite ply, and running some balsa stringers about 1/3 of the way back up the fuselage. This will give a firm foundation for the plywood firewall that I will be installing, and keep the motor from ripping off the tail.

I will be running about 450 watts on this one, so I want to make sure that the motor has a firm hold on the hind end of the plane!

Lucien
Aug 12, 2006, 05:36 PM
EB-66C Team Member
J Morgan's Avatar
Good idea Lucien. I used fiberglass both sides on my 36" ws and carbon tubes inside on my 42" ws.

J
Aug 12, 2006, 11:49 PM
Use the Force!
LBMiller5's Avatar

Installing the Wing & Stab Spars


As you may recall, I am making the Wing and tail surfaces from 2 layers of BlueCor for added stiffness and aerodynamic thickness. Since my flying surfaces will be 1/2" thick, I decided to route channels into the foam, and embed the spars inside the wing. This will look much nicer than cutting a slot into the wing.

The spar I am using in the wing measures 0.296" in diameter. A 5/16" round cutter head measures 0.312" in diameter. By using this to cut the channel for the spar, it will leave a few thousandths of an inch of space to allow for a nice coat of glue. For those of you that have never done this before, I will explain the process.

First, you need a ball cutter for a Dremel tool. You also need a router attachment. Here is a shot of the 5/16" ball cutter and the router attachment installed onto my Dremel tool.





The router attachment has a depth adjustment on it so you can slide it up and down to control the depth of the cut. I set the router so that the ball was exactly halfway exposed below the bottom of the router head as shown below.





To provide an edge to guide the router, I taped my 48" metal ruler to the wing. The ruler needed to be 1-1/8" away from the desired cut line to allow for the diameter of the router head. Here is the wing with the ruler in place. I also have tape on the back side of the wing to insure the ruler does not shift during the cutting process.





A quick pass along the ruler with the router, and I had a perfect half round channel for the spar. Here is a close-up shot of the groove that was cut into the foam by the router.





Next, I test fit the spar into the slot. Perfect Fit! I will cut the spar to match the span of the center section of the wing and glue it into place when I laminate the wing panels together. Here is the spar being fit into the slot.





I repeated the above process for the upper wing panel being very careful to precisely measure the location of the slot so the two panels would fit together properly. After cutting the second slot, I crossed my fingers and put the two panels together with the spar in place. All the measuring paid off, since the panels fit together perfectly. Below is a close-up that shows the spar captured between the 2 panels. As you can see, there is just enough space around the spar for a nice film of glue.





When I cut the slots for the wingtip dihedral braces, I will put one of them right along the edge of the spar to help reinforce the wingtip glue joint. I also plan on putting a piece of 1/2 x 1/8 inch balsa on the tips of the wing and the trailing edge. This will help stiffen the panel and provide a nice strong edge to protect the wing from dings and dents. On the leading edge of the wing, I will use a piece of 1/2 x 1/4" balsa. The larger piece will allow me to sand a half round profile on the leading edge of the wing for good airflow over the wing. This also strengthens the leading edge a lot and protects it during the belly landings into the grass.

Since this plane will have significantly more power than it's smaller brother, I wanted to reinforce the stabs a little as well. On the original plane, the stabs have 22.5 degrees of anhedral in both stab halves. Plywood braces are used, just like on the wingtips, to reinforce the joint, but I wanted a little bit more strength. The plan is to add a carbon fiber spar to the stab halves as well, and where they go through the fuselage, I will put a balsa former to provide a nice surface to glue the spar ends to.

First I had to cut the slots in the stab halves. Since the back end of the fuselage tapers, I needed to take this into account when I cut the spar slots. To set the proper angle, I used the rear lower fuselage piece as a form, and taped the lower stab panels to this piece in the proper orientation. Here is what everything looked like at this point.





Next I marked the position of the leading edge of the elevator and drew these marks on the root edge of the stab halves. Then I positioned my straightedge so the spar would be about 1/2" ahead of the elevator hinge line. I am using a slightly smaller spar in the stabs than I used in the wing. The stab spar measures 0.226" in diameter, so I used a 1/4" (0.250) cutter to cut this slot. I used the same process I described earlier to cut the slot in the stab halves. I stopped the cut in the middle so I did not mess up the lower fuse sheeting piece. Here are the stabs after the slots were cut.





After I cut the slots in the bottom stab panels, I repeated the process for the top stab panels. After cutting the slots, I did a test fit of the spar into the slots to see how the upper and lower panels lined up. Just like the wing panels, they lined up great! Here is the left stab with the spar set into the slots. You can see the weird angle at which the spar goes through the stab, and if I had not used the tail piece to line up the stabs, there is no way that I could have gotten that angle correct.





I will cut the tips of the spars at an angle to match the leading edge of the stab. Just like on the wing, I will put a piece of 1/2 x 1/8 inch balsa on the trailing edge and tip, and then put a piece of 1/2 x 1/4 inch balsa on the leading edge so they can be rounded off. The inboard end of the spar will be left sticking out a little over an inch to secure into the fuselage.

Now I just need to laminate all the surfaces together and they will be good to go. Since the rudder is so short, there is no need to put a spar into it. The balsa edging will provide enough stiffness to strengthen the rudder.

That is it for this installment. Time to get back to building the fuselage.

More to come tomorrow!

Lucien
Last edited by LBMiller5; Aug 14, 2006 at 02:44 PM.
Aug 13, 2006, 08:16 AM
AA6JB
Bajora's Avatar
I've used that same technique Lucien, to cut a slot for the spar. I didn't think to use the straightedge of the ruler though! Thanks. I love my Dremel.

Your F4 is looking really good - keep up the great work!
Aug 13, 2006, 09:00 AM
JAM
JAM
MaxAmps CMO
JAM's Avatar
That's just plane cool......mt wife got me the newest dremel kit last x-mas and I think I use it just about every day and he router attachment is great. I'll be watching this to see how it turns out, I have a couple of larger motors out of some balsa planes that need new homes.

JAM
Jason


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
New Product 6mmFlyRC-F-4 Phantom II CBflyguy Pusher Prop Jet Models 602 Apr 17, 2016 11:31 PM
Yippee! Enlarged Plans for 6mmFlyRC F-4 Phantom Added!! LBMiller5 Pusher Prop Jet Models 3 Aug 18, 2006 08:00 PM
FS: Factory New AERC F-4 Phantom Taking Pre-Orders Now gbagley Aircraft - Electric - Airplanes (FS/W) 9 Oct 16, 2002 08:50 PM
Great Planes F-4 Phantom greenshirtrwg Fuel Plane Talk 0 Jun 05, 2002 10:25 AM
F-4 Phantom II - First look... Daren Electric Ducted Fan Jet Talk 139 Mar 18, 2002 12:27 PM