The RC Geek Blog

By: Chris Wolfe

Rudder me This!

Final test fit of the dorsal before fibreglass

With the final shape of the dorsal completed for our RC Jet, it is on to cutting out and shaping the rudder. On the full size Skyray, the rudder was split into an upper and lower half.  The upper portion acted as a yaw damper primarily while also acting in unison with the rudder.  The lower half acted as the primary rudder surface.  Interestingly, in looking at videos of the Skyray in flight, the yaw damper doesn’t seem to act much in unison with the rudder at all.  Also, in talking with Mark Frankel, the rudder is quite effective on the model causing it to roll pretty substantially.  So, based on those two things, my intention on this model is to make the yaw damper fixed and use the lower half as the rudder.  We will be cutting out both the damper and rudder and splitting them, but when final installed into place, the yaw damper will be fixed.  This way, it will still appear to be a moveable surface.

 

Cut it…

Rudder template in place, ready for cutting

Checking my 3-view to the plans, I traced the rudder shape and transferred it to the dorsal.  The key here when plotting it out is the allowances for the balsa rudder cap (in this case it’s about ½” of material) as well as the spar in the dorsal itself.  In other words, ½” of the rudder leading edge will be removed and thrown away and replaced with a solid balsa cap that gets sanded to shape.  Also, I had to take time to ensure I accounted and had a plan for the location of the spar so I had the proper scuffer setup on the dorsal as well once everything is hinged.  The idea is to have a nice scale looking flange on the dorsal and rounded leading edge on the rudder.  The Skyray has an offset hinge setup on the rudder, so this was kept in mind throughout.  Once sure that everything was right (measure twice, cut once!), I moved on to cutting the rudder out.

I used tracing paper to trace the outline and cut the outline out of the tracing paper using a straight edge and an X-acto knife.  From there and then used 3M 77 spray glue to tack it down onto the dorsal surface.  Again using an X-acto (use a fresh sharp blade) and a straight edge, I cut the rudder surface away from the dorsal using the traced outline as the template.  It was done by cutting the rudder outline halfway through on one side of the dorsal, transferring the template to the other side and then doing the same thing.  To cut through the 1/64” ply TE stiffened, a fresh razor saw works well.


Rudder cut and ready for the next step

Rudder cut and ready for the next step


Rudder LE glued in place and dorsal spar test fit

Rudder LE glued in place and dorsal spar test fit

Shape it…

template marked and LE sanded to shape

With the rudder now removed from the dorsal, it’s a matter of getting the spar cap on the rudder and the spar into the dorsal.  In the case of this design, it’s a balsa cap on the rudder with a 1/8″ spar installed into the dorsal.  First, the balsa rudder leading edge spar cap was glued using titebond.  With the rudder LE on and the glued cured, it was sanded to shape. Given the offset hinge design of the real deal (the purpose of this on the full size is to help reduce surface hinge loads), the rudder has a nice rounded LE.  This was accomplished by using a circle template to trace the shape on each end of the rudder and the LE the rounded according to those markings.

 

Spar it…

Foam cleared for the spar with allowance for the rudder scuffer

For the rudder spar, I had to remove foam from the inside of the dorsal to allow for the 1/8” spar as well as the balsa rudder LE.  In this case, we are going to use the balsa sheeting as the rudder scuffer, so only the internal foam is removed.  In other cases/designs, we might cut out a section of the dorsal to allow for a balsa spar and create the scuffer differently using 1/64″ ply strips (that will come with the wing).  Double checking the fit and depth of the spar with the rudder, the spar was epoxied in place.  Some micro balloons were added to the mixture to give a little better thixotrpic properties while

Spar epoxied in place

also lightening the epoxy.  Lastly, based on the design, the spar extends well below the dorsal as an attachment to the fibreglass stub fin.  So, some sheeting was added so that it matched up to the fuselage.  Some balsa filler was used to get a rough matching contour to the fuselage stub fin.  Once glassed an glued to the fuselage, that intersection will be cleaned up smoothed out completely.  Lastly, I beveled the inside edges of the rudder scuffer so that when glassed, the scuffer will have a nice sharp edge to it and not interfere with the rudder.


Rudder test fit with before glassing

Rudder test fit with before glassing


Test fit of dorsal

Test fit of dorsal


Test fit of dorsal, not the beveled scuffer edges

Test fit of dorsal, not the beveled scuffer edges

Next time we’ll discuss glassing these parts a bit and hinging the rudder or our F4D Skyray RC jet.  Here’s a sneak peek to give an idea where we’re headed…

Dorsal and rudder assembly following glassing

 

The post How to Build an RC Jet – Part 4 appeared first on The RC Geek.

The RC Geek Blog is your place to learn about all aspects of the RC hobby. Learn to build, design, drive or fly that RC project you’ve always wanted to build, but have been intimidated to try. This blog is here to help you on your journey and provide tips and tricks as you go! My hope is to inspire builders both experienced and new! So, welcome, please look around, it’s an exciting beginning!  I’m currently documenting my latest competition scale RC jet build, a Mark Frankel F4D Skyray, along with some other fun tips and videos. If you can’t find what you’re looking for on this front page, click on any of the categories to the right and it will show just posts related to those categories. Please feel free to add comments and/or contact me directly if you have questions, I’m here to help! And don’t forget to check out my YouTube Channel, I post new videos every week!

Subscribe To Our Blog Now

By Chris Wolfe 19 Sep, 2023
The B-58 Hustler Saga - From Triumph to Tragedy
By Chris Wolfe 13 Mar, 2023
Preparing for Battle: The ULTIMATE Guide to Scale Documentation Maybe you've heard about RC Scale Aircraft competitions, but the thought it sounded intimidating, or the process of it all seemed daunting and discouraging. Well, fear not! I am here to encourage you and dispel any myths you may have heard if any. Scale competition is a fun and challenging segment of the hobby that will undoubtedly make you a better pilot! So, in light of this, I've started a new "Preparing for Battle" live series and in my first episode, "Preparing for Battle: The ULTIMATE Guide to Scale Documentation," we talk about the AMA Scale Nats with special guest Joe Vermilion from Balsa USA and peel back the layers of scale competition and provide information on what it's all about! As an experienced RC Scale Aircraft competitor and two time US Scale Masters National Champion, my hope is to share whatever knowledge and practical advice I can for newcomers and seasoned competitors alike.
By Chris Wolfe 14 Feb, 2023
Are You Ready to Take Your RC Flying to the Next Level?? Then you’re in luck, because we’re giving away an FMS 1400mm F4U Corsair and an FMS 1100mm PC-21 ! But first, let's address the elephant in the room...it's been quite a while since my last blog post. With the move to TN and everything going on trying to get The RC Geek up and running full time, it's been difficult to sit down and set aside time to write. My goal is to change that going forward, so here's hoping! (check the vid below for even more details about everything mentioned here!)
By Chris Wolfe 25 Jan, 2022
Flight of the Flir Cat…The Sequel!! I tell you what, it has been quite the journey getting here! As a project, this Freewing F-14 Tomcat refinish took much longer than I had originally planned based on all of the other distractions that have come through the shop, but I'm so happy with how this model turned out in the end. It did take a few flights to get tuned and I have made a few small modifications in the process since our last installment, but otherwise I'm happy to report that the Tomcat is flying quite well. The F-14 Tomcat has such a great look and presence in the air, you just can't beat it!
By Chris 10 Jan, 2022
10 channels of power…and 1 receiver to rule them all! I personally love having the option for more channels, especially when building my own scale aircraft. While not always necessary, having channel options available is almost always helpful and it opens up opportunities to add scale functions and/or customize the controls more to your liking. And that's not to mention having individual servo setup across the same functions. So, I was excited to finally see the AR103060T and AR10100T 10 channel receivers released from Spektrum. It opens of channel options in a lighter weight package while also supports all of their new technology. Having been flying the NX10 for some time it is nice to finally be able to utilize all of those 10 radio channels.
By Chris 10 Jan, 2022
Good times and Warbird Flying are back! Needless to say, the last year and a half plus has been hard on all of us. With so many of our normal routines and activities disrupted, it has only brought that many more challenges it seems. This hobby is not just about the airplanes and flying, it is about the friends and comradery that can be enjoyed together with others as well. So, when the Scale Squadron's Warbirds & Classics came up again this year after being cancelled in 2020, I was beyond excited to go; it had been almost 2 years since the last event I went to!
By Chris 24 Nov, 2021
Refinish a Foam Jet Ep 4 – Freewing F-14 Tomcat Low-Viz Navy Weathering How low can you go?…a little low-viz Tomcat weathering. Finishing up the refinish work on the Freewing F-14 Tomcat, it’s time to apply some characteristic low-viz Navy weathering. The Flir Cat paint scheme is from the mid 90’s at a time when the Tomcats in service were painted primarily in Dark Ghost Grey (FS36320) with variations thereof. They were high maintenance workhorses at this time and the aircraft got extremely dirty during operation. This opens up lots of opportunities to apply different weathering techniques on the airplane to simulate those years of service on the carrier.
By Chris 24 Nov, 2021
Refinish a Foam Jet Ep 3 – Freewing F-14 Tomcat Paint, Markings, & Panel Lines
By Chris 27 Sep, 2021
Refinish A Foam Jet Ep 2 - Freewing F-14 Tomcat Cockpit 3D Printing, Painting and Moving Pilots
By Chris 27 Sep, 2021
Fill…sand…poly…sand…primer…sand…aaaannnnddd repeat… You've probably figured out by now, I have many favorite aircraft. ;) However, if I was to put together my top 5 favorite aircraft of all time, the F-14 Tomcat would probably be at or near the top of that list. The airplane was one of brute force, but packaged in an elegant and distinct looking airframe that truly personified its name, Tomcat. And that's not to mention, it was an extremely capable fighter that filled many roles through the years that operated from the early/mid 70's into the mid 2000s.
More Posts
Share by: