Having grown up with the CF18 as a fighter controller in the Canadian Air Force for almost 30 yrs, I have always had a soft spot in my heart for the F18 Hornet. From a standpoint of RC modelling, the RC Powers F18 V3 is probably in the top five of my all time favorite park jets. The F18 V3 helped me take my flying skill and confidence to an entirely new level and for that I will always be thankful.
I will caveat this and follow on posts about my modified F18 V3 by saying that if you are a beginner or new to the hobby, the F18 V3 built stock is by far one of the best planes you can build and fly to help you get started. Also, RCP offers the plans for free now, so no requirement to buy anything other than components and build materials. As my RC parkjet career approaches it's 3rd anniversary however, I am constantly looking for ways to push the envelope with my planes to get them to look and fly the way that I like them, hence why the modifications I and my NAMC partner Stephan have made to almost every plane we have ever built. To me this is no comment on the designer, but rather the beauty of scratch building foam park jets as it allows a person to have the freedom to experiment. As we found with developing the NAMC Mig-35 and Mig-FA, you just never know what you might find out with some thorough research and testing.
This old gal had just over 350 flights on her when I decided to retire her
About a year and a half ago, I did play around with some significant modifications to the F18 V3 which I discuss in this video
Around that time, RCP released the V4 series of their planes and Stephan and I started doing some serious work modifying and testing the Mig-29 V4 which led to our NAMC Mig-35 and as they say the rest is history. However, playing around some more with the F18 V3 has always been on a "slow simmer" at the back of my old brain, so time to bring it forward and have some fun. Plus I had an old set of plans collecting dust in my closet that needed to get used up. :)
Through the development and testing that has gone one with the Mig-35 and Mig-FA for almost the last year, my learning curve has been very steep but incredibly rewarding. Stephan's scientific approach to design and our shared desire to squeeze the maximum performance from our planes while still having them look amazing has led us to a very unique place in park jet design and testing. Or at least I like to think so :)
So armed with this knowledge I have learned from Stephan and the experience I have gained through 940 + flights testing the Mig-35 and Mig-FA, I see great potential for many of these principles to cross over to another airframe, the F18. Plus, depending on how the testing turns out, it will be continued proof that the science behind why the Mig-35 and Mig-FA perform so well is universal to any park jet platform.
So here are just a few things I think can be improved on the F18 V3 to make it a more tight, precise, high performance park jet. Many of these principles I discuss in more detail in this video below. Additionally, I would encourage you to go to our NAMC video page to watch Stephan's excellent educational videos on PMI/centre of gravity and centre of mass as it relates to aircraft design and performance.
- shorten the polar moment of inertia (PMI). As most of us who have flown this plane discovered, we needed our battery all the way against the bulkhead to balance it, meaning the weight was spread over a very large area of the longitudinal axis making pitch manoeuvres and turning more challenging than it needs to be;
- find the correct CG (centre of gravity) in all three axes. First is the longitudinal or pitch axis. Before Stephan opened my eyes to other possibilities, I always strived to balance my plane on the stock (or by the plans) CG. This is fine, but by their own admission, most RCP planes are balanced nose heavy to help beginners and looking back on it, I'm sure I was flying my F18 far too nose heavy;
- work to concentrate the CG, CM (centre of mass) and CT (centre of thrust or motor location) in as tight an area as possible. As we found with the Mig-35 and Mig-FA, this is critical to making manoeuvring tight, precise and effortless from a standpoint of control surface deflection. Meaning having science working with me instead of against me;
- fine tune the size of the control surfaces. I had started to do this somewhat with the plane in the first video above, but I still need to fine tune the ailerons and rudders;
- dial in the size and location of the KF airfoils, especially how the trailing edge of the airfoil relates to what I find as the optimum CG; and
- set up the airplane and transmitter using the principles described in the second video above to maximize feel and precision.
So, how do I plan on doing this?
- First off, I will shorten the overall length of the plane by about 1.5" and increase the wingspan by about 1/2". This will bring the dimensions into scale proportion not only to help the plane move more quickly and easily but hopefully make it look a little better too. I have always felt the nose was a bit too "pointy" for my taste, but again, personal preference does enter into things occasionally;
- I will move the motor forward 1". This should help shorten the PMI and move the CG back bringing the CG, CM and CT closer together;
- Once I have a flying prototype, I will spend several flights dialing in the correct CG using methods described in the second video above. I will also assess the "vertical" CG to determine if the plane is top or bottom heavy WRT to battery location;
- I will start off with the stock KF airfoils and then once I start the final dialing in on the optimum CG will modify them until the trailing edge of the KF is coincident with the CG for maximum performance; and
- servo location will be planned to try and concentrate the weight around or very close to the CG and to allow for best setup for precision flying.
So although this blog has been inactive for awhile, I think it is the best place to discuss my mods to what I will call from now on the F18 V3M (M for modified).
I will continue to update as I move along in the build and testing process. Time to get cutting some foam! :)
Cheers,
Scott
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