Cermark F16 Propjet Build Log Page 1

A 130+ mph scale model of a General Dynamics F16 with the Thunderbird color scheme.

Introduction

Welcome to the Cermark F16 Prop Jet build log. I decided to add this little speed demon to the hangar after looking pretty hard at a number of kits this summer. I started reading some forums on the plane and people that have it give it pretty good marks for flying qualities and overall kit quality. As the plane comes together, I will post narratives and photos that may help others along the way should they elect to build one.

Initial Hints and Kinks from Fellow Modelers on the Kit

Landing Gear Mounts

The only common complaint I found in the groups is the poor retract gear mounts for the mains and nose gear. The mounts consist of 2 pieces of soft 1/8” ply sandwiched together and glued to formers forward and aft, yet the mounting plates are not glued to each other. They need to be reinforced with additional plywood and epoxy so they are more resistant to breakage on less-than-perfect landings. A fellow member of the Yahoo! Prop Jets group ripped the mounts out the first day he flew it and promptly wrote up a fix. Interestingly, Cermark is aware of this condition, but has yet to fix the problem with improved construction in this area. I’ll detail how I handle this later in the log when I get to the gear mounts which will be sooner than later.

CG Typo in Assembly Manual

Builders of this airplane should also be aware of a typo in the assembly manual that has gone unchecked since at least April 2006. The CG is listed as being 8 ½ inches aft the leading edge of the wing measure at the root in several places in the assembly manual. This is incorrect. The correct CG is 7 ½”. Cermark is also aware of this, but again, have for reasons unknown, not corrected the manual.

Planned Setup

Radio - Spektrum RC DX7 with AR7000 7 channel receiver

Battery - MPI 6 volt, 2700 mah NiMh

Engine - Jett Engineering SJ .90LX high performance glow engine & tuned muffler

Stated Performance: 17,000 rpm with APC 11 x 8

Landing Gear - "Air-Up/Spring Down" mains and nose gear pneumatically retracted, spring deployed. Supplied by Cermark as an option.

Servo Compliment - Elevators, Ailerons and Nose Gear Steering: HiTec HS-645MG (5) (metal gear)

Rudder: HiTec HS-85MG (1) (metal gear)

Throttle and Landing Gear Actuator Valve: HiTec HS-311 (2) (standard nylon gear)

Note: Alternatively, HiTec digital servos could certainly be considered for primary flight control surfaces, but would add a fair amount of cost to the project as four servos are needed. The ones listed here in the setup are metal geared except for the throttle and landing gear servos.

Initial Photos

I’ve had the plane sitting in the box for a few weeks now. So many people can just unpack it and get going, but I have limited space and there are other projects on the bench right now. All in good time, though. I did unpack the box to make sure nothing was damaged in transit and sure enough, it was in good shape. Here are some pictures of how the F16 looks coming out of the box and the mighty Jett 90.

Click on the pictures below to enlarge to full size.

F16-out-of-the-box/Wing-tube.JPG F16-out-of-the-box/Retracts.JPG F16-out-of-the-box/F16-box.JPG F16-out-of-the-box/F16-in-box.JPG

F16-out-of-the-box/F16-laid-out.JPG F16-out-of-the-box/Misc-Hdwe.JPG F16-out-of-the-box/Manual-misc.JPG

Posted Sunday, November 16, 2008

By mid-afternoon this Sunday, I finally found my way clear to get started on the F16; after several months with the plane remaining in the box, I got everything pulled out, packing bags removed and all the additional items needed all laid out as I make ready to start assembly.

I have everything (I think) needed to get the bird built. There will be time during the weekends, holidays and nights in the coming months. Winter is doing a fine job of settling in for an extended stay, so flying is tabled until spring or a suitable day comes along.

So, what did I get done? It's all unpacked, the shipping box has been cut up into smaller trash can sized pieces and I performed an initial charge and discharge of the MPI 6 volt, 2700 mah battery which will serve all functions on this plane.

Before doing all this, I treated the 31 inch x 11 foot workbench with a piece of carpet I found at the local carpet and wood flooring shop for $15. This will help to keep the parts from getting scuffed and scratched.

Here's what it looks like today.

F16-11-16-08/F16-fuse.JPG F16-11-16-08/F16-accessories.JPG

Fuselage at left and all the goodies at right waiting to be assembled

Smoke or No Smoke

There will not be a smoke system on this project. Too much added weight and the fact that getting a 2 stroke 90 to do smoke without pre-heat would not work well. So, it's out. I briefly researched wing tip strobes, but haven't figured out how I'd run the wiring to the wing tips.

This concludes today's activity in the skunk works.

Go to Build Log page 2 HERE

Rick Tressler - Columbus, Ohio

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