Balsa F-18A Pusher Jet for FPV - RC Groups
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Oct 17, 2017, 10:15 PM
AndyKunz's Avatar
Build Log

Balsa F-18A Pusher Jet for FPV


Anybody who knows me can guess that this one is slightly outside my normal construction project, but there's a darn good reason - my grandkids.

My oldest son used to live in Pensacola, and his two young boys are die-hard Blue Angels fans. The elder wants to be a Blue Angels pilot when he grows up. I figured, "Why wait?!"

The logic behind the various elements of the title:

BALSA - my favorite material, and it cuts on the laser without stinking up the whole neighborhood.

F-18A - because these little tykes know when it's not an F-18. The A model is my reference for simplicity - the leading edge is straight. I'll probably take a little liberty with the intakes, which should be rounded off.

Pusher Jet - because EDFs have killed too many of my batteries, and they just don't perform as well. Besides, I have a pretty good collection of motors for this project.

FPV - "Andy!?!? FPV?!?!?" Yes, but not for me. My plan is to borrow some goggles from a friend, install a pan/tilt servo on the camera in the cockpit, and then give my grandsons the thrill of their lives. How many preschoolers can say they've flown in an F-18?

My original plan was just to adapt Steve Shumate's foam F-18, but I wanted it a different size, built-up wing, etc. It was easier to just draw up an outline from some 3-views I found online (attached).

It took a few weeks of evenings, but eventually I ended up with a bunch of laser-cut ply and balsa parts needing to be assembled. After taking care of other priorities over the summer, I'm now in a position to start building this puppy!

Upon weighing things, I decided immediately to put it on a diet. That's why the photo of the parts laid out on the laser cutter is different than the parts you see being glued.

Construction began by adding balsa doublers over the lite ply sides. There are numerous tabs and slots in this plane, and they work well to making sure things are aligned for gluing.

The next step was to assemble the nosewheel compartment. The pieces are labeled for left and right sides, and tabs plug into slots to help ensure alignment.

Andy
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Oct 18, 2017, 05:54 PM
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jpurcha's Avatar
Mike Pastro had a F/A-18 pusher model in 0.40 and 0.60 in RCM in the 1990's. Several of these have been built. I built the .40, but haven't flown it yet. Plans are on Aerofred. Watching this thread.

Jim
Last edited by jpurcha; Oct 18, 2017 at 07:24 PM.
Oct 18, 2017, 06:18 PM
UAS Pilot - FAA# *******HRK
CryHavoc's Avatar
Quote:
Originally Posted by jpurcha
Mike Pastro had a F/A-18 pusher model in 0.40 and 0.60 in RCM in the 1990's. Several of these have been built. I built the .40, but haven't flown it yet. Plans are on Aerofred. Watching this thread.

Jim
I can tell you were thinking the same thing I was when I saw this thread. I built the .40 size as well when the plan first came out. We had a dirt field back then and rocks kept taking out the prop so I never got to fly it. Later on we got a paved runway but it had been stolen from where I was storing it along with a bunch of planes and engines I had.

Needless to say I'll be watching this thread as well. I like the things Andy is doing with his plan. Maybe the Pastro plans need some updating.

Mike
Oct 18, 2017, 06:25 PM
AndyKunz's Avatar
I didn't even bother to look! I just went and downloaded the Pastro stuff from Outerzone. Something to review tonight. Thanks!

Andy
Oct 18, 2017, 07:26 PM
Registered User
jpurcha's Avatar
I agree it could use some updating in the construction. The glued butt joint and fibreglass for the rudders should be change. A nice electric version would be cool.

Jim

Quote:
Originally Posted by CryHavoc
I can tell you were thinking the same thing I was when I saw this thread. I built the .40 size as well when the plan first came out. We had a dirt field back then and rocks kept taking out the prop so I never got to fly it. Later on we got a paved runway but it had been stolen from where I was storing it along with a bunch of planes and engines I had.

Needless to say I'll be watching this thread as well. I like the things Andy is doing with his plan. Maybe the Pastro plans need some updating.

Mike
Oct 18, 2017, 10:04 PM
AndyKunz's Avatar
The Pastro version reminded me that I need to talk about size of mine. It has a fuselage length of 48.5" and a span of 32", making it a good bit smaller than his .40 size model. For power I have options of either the EF1 Power 25 or the motor from the E-flite Scimitar (a drop-in 40 replacement), which is pretty close to what I have on my 40-size Kaos, Drill Bit, and Shrike models. If my spreadsheet estimations are correct, I could build it as light as 3.5 pounds with the 25 and no gear, up to 4.4 pounds with the 40 and retracts.

So, back to construction.

Last night before leaving the shop I glued the main gear mounting plates together. These have a top and bottom due to the angle that the are in the fuselage. I attached them to the gear and used the blind nuts and 4-40 bolts to clamp everything together in alignment.

This afternoon I lightly sanded the tabs where they plug into F6 and F7 so that there would be a snug mechanical fit. I then applied a little glue into the joints and a clamped them together, then slid this assembly onto the fuselage sides.

A note here: it's wise to dry-fit everything to make sure the parts actually slide together BEFORE you try gluing them. Just sayin'...

I then clamped the fuselage top to bottom at these formers so they had the right depth, applied glue, and set the whole deal aside for the evening.

I really appreciate the comments, guys. The Pastro plans should be helpful - already I see that his balance point is a little behind the one I calculated for my plane, so I'm in the safe side of the ballpark.

Andy
Oct 18, 2017, 10:18 PM
UAS Pilot - FAA# *******HRK
CryHavoc's Avatar
Quote:
Originally Posted by jpurcha
I agree it could use some updating in the construction. The glued butt joint and fibreglass for the rudders should be change. A nice electric version would be cool.

Jim
I didn't see your picture earlier... Awesome job!

I did mine in a Marine Corps VMFA-232 "Red Devils" livery as that was the squadron a good friend of mine was in. Unfortunately no pics but I found one that I modeled mine after. Would love to do it again and actually see it fly.

Mike
Oct 18, 2017, 10:19 PM
UAS Pilot - FAA# *******HRK
CryHavoc's Avatar
Quote:
Originally Posted by AndyKunz
I didn't even bother to look! I just went and downloaded the Pastro stuff from Outerzone. Something to review tonight. Thanks!

Andy
Nice... He did a Warthog too. Hint, Hint.....
Oct 18, 2017, 10:25 PM
Registered User
jpurcha's Avatar
4 lbs and landing gear. This is looking interesting everyday. Since this plane is approximately a 25 size model. Model Airplane News featured a sport F-18 in a 30 size model range.

Jim
Last edited by jpurcha; Oct 19, 2017 at 08:07 AM.
Oct 19, 2017, 10:13 AM
AndyKunz's Avatar
Quote:
Originally Posted by CryHavoc
Nice... He did a Warthog too. Hint, Hint.....
I did one already too. https://www.rcgroups.com/forums/showthread.php?2315639

Andy
Oct 19, 2017, 10:17 AM
AndyKunz's Avatar
Quote:
Originally Posted by jpurcha
4 lbs and landing gear. This is looking interesting everyday. Since this plane is approximately a 25 size model. Model Airplane News featured a sport F-18 in a 30 size model range.

Jim
I just searched their site with no hits. Got a link?

Andy
Oct 19, 2017, 03:11 PM
Registered User
jpurcha's Avatar
http://www.airagestore.com/sport-f-18-hornet.html

Jim

Quote:
Originally Posted by AndyKunz
I just searched their site with no hits. Got a link?

Andy
Oct 19, 2017, 08:31 PM
AndyKunz's Avatar
Thanks for the link, Jim. That plane has the same span but is several inches shorter. I'll have to think about getting a copy and comparing.

Today I attached formers F8-F11 and made sure they're all aligned on center. This caused a few tweaks to the cut files - I changed F7 and F8 so that the channel stays in place until after assembly, and is marked for the center line.

One little hint but you really can't see it in the photos. I don't want glue dripping onto my Formica, so I put some clear cellophane tape on the bottom edge of the fuse. If any of the Titebond drips off, it'll be going onto tape instead.

I haven't started on the CAD for the wings or tail yet, otherwise I'd be building them while the fuse glue cures.

Andy
Oct 19, 2017, 09:02 PM
Registered User
jpurcha's Avatar
I have that too! Excuse the water mark from coreldraw. I'll clean that up tomorrow. Added the missing pages.

This is in the same size range of your model design. 46" Length and 32" wing span.

Jim
Last edited by jpurcha; Oct 22, 2017 at 03:32 PM.
Oct 20, 2017, 10:03 AM
AndyKunz's Avatar
Jim, it looks like that PDF is missing page 75. The text at the top of page 76 (first of PDF) is from a sentence started elsewhere.

Thanks for attaching that.

Andy


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