NEW 2017 F-18 V5 Official Thread

Discussion in 'Scratchbuilding!' started by RCPowers, Mar 20, 2017.

  1. Flybyknight22

    Flybyknight22 Top Gun

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    That is great!

    I have scaled my F-18 V4 up to 120-150% and I thought mine was big but yours is HUGE!

    Great flight, great build, well done!
     
  2. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    I had these two beauties out for a good thrash today :) Here they are guarding my own "jet fuel" some good strong, black coffee!
    2017-10-04 09.05.18.jpg
    These two are far and away my two favorites of the V5 lineup that I have built (others include the Su-27, F-16 and Eurofighter) with the slight edge going to the F-22. This was the first time I had actually flown them both in the same flying session.

    As you can read on the F-22 thread, this is my second F-22, this one built with DTF with some more mods both for experimentation and to compensate for the extra weight of the paper left on the rear of the plane for strength.

    I have 95 flights on the F-18 now and as I have mentioned in previous posts and videos, it is a real "sports car" of a park jet compared to the F-18 V3 (another of my favorites) which served me well for hundreds of flights at a critical stage of my development as a park jet pilot.

    So both the F-18 V5 and F-22 V5 are quick, agile, have about the same stability in the wind, again with the slight edge other than stability going to the F-22. So as I drank my coffee between flights and pondered why this is, a few things came to mind.

    I think it is obvious in this picture that the F-22 has a much larger wing area, therefore much lower wing loading at the same weight (both these planes are pretty much identical flying weight). Also, given that the F-22 has a flat plate bottom, that also provides some lift making the F-22 feel much lighter on the sticks.
    2017-10-04 11.08.57.jpg

    Also, what is very apparent in the picture is how much further forward the motor and component weight is in the F-22 (I moved the motor forward 1" to compensate for the DTF paper on the rear of the plane). Although high alpha is not a huge part of my flying skill set, it is fun for me to practice now and then. The F-22 is far superior to the F-18 in this part of the flight envelope. With the F-18 V5 balanced for the bulk of how I like it to fly, anytime I try high alpha, anything more than about 30 degrees angle of attack (AOA) and it is wing rocking pretty aggressively.

    So not that I am going to "Raptorize" my F-18, but it does give me a few ideas to experiment with in my next F-18 V5 build.

    - I think I will build it with DTF, the reduced drag profile can only improve it's quickness;
    - I will move the motor forward somewhat, both to compensate for the weight of the paper on the DTF in the rear of the plane and to move the weight forward for better high alpha performance and also tighten things up even more around the CG;
    - I may also add just a tiny bit more wing area along the leading edge of the wing, in previous experiments with other planes, it doesn't take a whole lot of surface area to lighten up the wing loading and still maintain very scale looks. I'm thinking maybe 1/2"? I will have to study the current plane and the plans to see how that would look and work out.

    Anyway, just some thoughts, regardless the F-18 V5 is a ton of fun to fly as is, but always fun to experiment :)

    Cheers,

    Scott
     
  3. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    I have started to finalize my ideas for building my next F-18 V5 :) As I discussed above, I plan on building with DTF except the nacelles which will probably be made with scrap MPF or Depron depending on what I can find that will fit them.

    I plan on moving the motor forward about 1" not only to compensate for the extra weight of the paper left on the DTF behind the trailing edge of the KF, but also so shift more weight forward to see if that helps with improving high alpha performance. In addition to possibly adding a little more on the leading edge of the wing, I decided to add the "dog tooth/saw tooth" out near the end of the wing since with the square intakes, the F18 V5 is more of a "Super Hornetish" look.

    This will also add a tiny bit more wing area and perhaps better defence against wing rock at high angles of attack (AOA)? I printed off the appropriate page from the F18 V3 plans at 91% so that it would be about the right size to fit on the F18 V5 (based on differences in wingspan). I'm also toying with the idea of a slightly larger LERX like on the F18 V3, so I printed those pages off as well and then made templates from scrap foam.
    2017-10-20 13.50.31.jpg

    Not sure if it is going to make a huge difference, but it will be fun to compare and experiment. I still have my original F18 V5 intact and ready to fly, so it will be cool to compare the two and see what results I get from my experiments. :)

    Cheers,

    Scott
     
  4. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Been busy with ruler, pencil and dollar store calculator :) Where the blue pencil and scissors are point is probably where I will cut so that I can fit the main wing on a 20x30" sheet of DTF and then glue those pieces back together later in the build.
    2017-10-20 16.28.52.jpg
    I have done several things, moved the motor mount and rear electronics bay forward 1". Added the "dogtooth" on the wing tips. I decided after looking at my stock F18 V5 that adding more wing area than that would be a bit too much, so no extra wing area other than the addition of the "Super Hornet" dogtooth/sawtooth at the end of the wings.
    2017-10-20 16.29.10.jpg
    In this picture above, I also drew out roughly what my KFs would look like. I have found that about 40% of the wing chord at both the tip and wing root seem to work best for the many different F18s I have built, so that is what the outline currently represents, these will be fine tuned after the wing plate is cut out.

    I also decided to increase the size of the ailerons in both span and chord. Not so much for general flying, but I am hoping by having a bit more surface area to deploy as flaps or spoilers may also help me experiment more with slow flying and high alpha. In surface area, as a rough guess, I would say I increased them by about 40%?
    2017-10-20 16.28.58.jpg
    As mentioned before, I did expand the size of the LERX a bit as well to see if that helps with higher AOA flying.
    2017-10-20 16.29.22.jpg
    Probably start cutting foam over the weekend :)

    Cheers,

    Scott
     
  5. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Parts are all cut out, including the KF4 :)
    2017-10-21 11.18.20.jpg
    Although I used MPF for the engines/nacelles and the motor mount supports, if a person was careful, it would be quite easy to build the entire plane including KF4 airfoils with only 3 sheets of DTF.

    After looking more at my original F18 V5, I decided to reshape the vertical stabs somewhat, just something about how they looked...

    So I again printed an F18 V3 vertical stab at 91% and overlaid it on the original V5 vertical stab. I don't think I lost a whole lot of surface area, just reshaped it a bit, made it less deep in chord at the base and wider at the top and angled differently front and back. I kept the rudder the same size. We will see how that looks and works :) I'll keep the original templates for the V5 in the event it doesn't look right when I dry fit them later in the build.
    2017-10-21 11.23.15.jpg

    Cheers,

    Scott
     
    Last edited: Oct 21, 2017
  6. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Still plugging away on my DTF F18 V5 build :)
    2017-10-23 09.18.53.jpg
    Like I did with my first build, I dropped the battery tray to the bottom of the fuselage which if I was to guess is about 3/8" lower than stock? I still cut out the battery tray from the plans, trimmed off the tabs and glued it to the bottom of the fuselage (velcro still needs to be attached to hold the battery). I'm hoping this will keep that area nice and strong when the battery is being secured and removed multiple times. Also, for another project I'm toying with, I want to see how strong two pieces of paperless DTF are when laminated together.

    I decided to go "old school" with my motor and dug out a Grayson Hobby SMJV2 with Master Airscrew 6x4x3 prop. I ran this for awhile on my first F-22 V5, lots of power and torque, adds some weight, it is 35 gr/1.2 oz heavier than the DYS 2208/7 2600 motor I am running in my first F18 V5, I'm hoping the extra weight will give it a bit more presence in the wind and stability at higher AOA. Worth experimenting with anyway :) If most everything else remains the same, it will put my plane around 21.5 oz with a 2200 3S battery which is about the most common weight I fly most of my park jets in this size range. With the increase in my LERX area and the little bit extra with the Super Hornet "dogteeth" at each end of the wing, I'm hoping the extra area will help with the extra weight. I am using 4 mm carbon rod for both wing spars like I did with my first F18 V5 and it has a very strong wing. I can still use a 40A ESC with the SMJV2, so I don't need to add any more weight to the power system other than the heavier (and more powerful) motor.

    After moving the motor forward, the motor mount is just behind the middle of the CG spectrum per the plans. Where the forward wing spar is located is the stock CG. Servo placement is going to be a little tricky as I still want to keep all the servos forward of the motor mount, but that will probably be determined further along in the build.

    Still in the fussy part of trimming off paper, need to add reinforcement to the back plate, vertical stabs and elevons, do some sanding and then it will be time to assemble the airframe which doesn't take much time at all with the simpler build process of the RCP V5s. Maybe have it finished on the weekend :)

    Cheers,

    Scott
     
  7. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    I know it looks a little rough, but I promise somewhere under all that tape and those pins is an F18 V5 :)
    2017-10-24 16.50.30.jpg
    The hatch door and tails are dry fit for now, everything else is glued and will set up overnight before final sanding tomorrow and then paint and gear installation will begin.

    I manged to squeeze all the servos ahead of the prop slot although it is a tight fit. In the picture below, from left to right will be my aileron, elevon and rudder servos.
    2017-10-24 16.37.08.jpg
    Before assembling the fuselage and nacelles, I cut matching holes through for cooling and to make it easier to run the servo wires into the electronics bay.
    2017-10-24 16.37.16.jpg
    To ensure I have a nice snug fit and the proper angle on the vertical stabilizers, I added some 3mm Depron which makes up 12 mm with the double layer of paperless DTF which is what it would be if it was built with MPF or Depron.
    2017-10-24 16.40.51.jpg
    Other than painting and gear installation, I still need to make some wingtip missile rails, but that shouldn't be too hard :)

    Cheers,

    Scott
     
  8. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Definitely looking much more "Super Hornetish" now :)
    2017-10-26 06.54.33.jpg
    All the sanding and sealing is complete, aileron and elevon servos and linkages are installed, just needs paint, motor and rudder servos and linkage and she will be ready.

    I weighed it at this point and realized that with my original choice of the "old school" SMJV2 motor, I could end up in the 625+ gr/22+ oz range which might be a bit too "hefty". So I will go with the DYS 2208 2600 Kv motor with the MA 6x4x3 prop instead, instantly saving 35 gr/1.2 oz. Also, since I have the DYS 2600 motor in my first F18 V5, this will allow me to have a much more equivalent "fly off" to see if my experiments on this second Hornet made any significant difference.
    2017-10-26 06.54.53.jpg
    So as long as I don't get too "slap happy" with the paint, fingers crossed I will still be around 595 gr/21 oz with a 2200 3S battery.

    Weather has turned nice, might be getting out to do some flying over the next couple days :), so the F18 V5 build will slow down a bit, but hope to have it finished and flying next week :)

    Cheers,

    Scott
     
  9. homey666

    homey666 Top Gun

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    Nice job, Scott! Looks like a ripper and yes..... Super Hornety.

    Peter
     
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  10. e3_Scott

    e3_Scott Top Gun

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    Thanks so much, Peter :) I just checked the motor test spreadsheet, the DYS 2208 2600 Kv motor with the 6x4x3 prop on 3S pulls 29.9 amps. Given I'll be flying this a lot in cooler weather, if I need to shave a few more grams off, I might also drop to a 30A ESC.

    I have a nice "two tone" camo paint scheme in mind for this one :)

    Cheers,

    Scott
     
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  11. e3_Scott

    e3_Scott Top Gun

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    Hi everyone -

    After taking a break to get some flying done, I got back to work on my latest F18 V5 and finished it off today :)
    2017-10-28 14.33.42.jpg
    2017-10-28 14.33.55.jpg

    With a 2200 3S battery, I ended up at 584 gr/20.6 oz which I think is within 0.1 of an oz of my first F18 V5, this new one is the lighter of the two.

    Build summary -

    Built with DTF (Adams readi-board) except the "engines/nacelles" which are made of MPF.

    Power system - DYS BE2208/7 2600 Kv motor, Master Airscrew 6x4x3 prop, Turnigy Plush 30A ESC, Zippy Flightmax 2200 3S 40C battery.

    Controls - Elevons (controlled by two RC Timer 9 gr nylon gear servos), ailerons and rudders all controlled by RC Timer 5 gr nylon gear servos.

    Modifications starting at the front -

    Narrowed the front and back of the canopy by about 1/4" by tapering it 1/8" on both sides not only for looks but hopefully make it a little sleeker in the wind.

    Enlarged the LERX. They are about 3/8" wider where they meet the leading edge of the wing and then slowly taper forwards towards the nose. Not sure if the difference is visible in the picture, it is with the naked eye when I look at the two side by side.
    2017-10-28 14.29.33.jpg
    I moved the motor 1" further forward to help compensate for the extra weight of the paper left on the DTF aft of the trailing edge of the KF airfoils. I am using KF4 airfoils, measuring 40% of wing chord at the wing root and wing tip. I added the "dogtooth" on the leading edge of the wing to make it look a bit more "Super Hornetish" Battery position is lowered to the bottom of the fuselage (I think about 3/8" lower than stock). Ailerons are lengthened and widened in chord, I would say at least a 30% increase in aileron area.
    2017-10-28 14.29.59.jpg
    I didn't really move the trailing edge of the prop slot too much further forward, maybe about 5/8". I changed the tails to more of the shape of those found on the F18 V3, narrower at the bottom than stock V5, wider at the top. Not sure if I lost a whole lot of surface area. I left the rudders the same size and shape.
    2017-10-28 14.32.33.jpg
    Paint scheme is a two tone "camo" using the Squadron colors of 410 Tactical Fighter Training Squadron from 4 Wing Cold Lake, Alberta https://en.wikipedia.org/wiki/410_Tactical_Fighter_Operational_Training_Squadron
    410_patch.jpg

    I worked with 410 Sqn throughout my entire Air Force career, starting when they were still the Operational Training Unit for aircrews flying the CF-101 Voodoo.
    voodoo.jpg
    Hope to get the maiden done sometime next week :)

    Cheers,

    Scott
     
  12. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Maiden complete on this little beauty :) Still dialing in the throws, it took me about six flights to get the CG right as it is considerably different than stock and my previous F-18 V5.
    2017-10-30 09.05.56.jpg
    My CG is about 1" ahead of dead center of the black rectangle on RC Powers CG spectrum. In this picture, where the tooth pick is sticking up is the stock dead center CG, the screwdriver is pointing to my CG. This CG is 1/2" ahead of where my CG ended up on my first build which was essentially by the plans.
    2017-10-30 16.20.35.jpg
    My battery ended up about 1 and 1/2 to 1 and 3/4" ahead of where it was in my first build.

    I'm not sure if my increasing the size of the LERX has accounted for more lift in the nose, but it took more weight forward to balance it on the CG. I had actually hoped this longer distance between the motor and the battery would help with high alpha performance. It did improve, but unfortunately not so much. Having watched real F-18s do high alpha numerous times at airshows, about a 40 degree AOA (angle of attack) seems to be a scale number to shoot for. With my first F-18 V5 at about 25 degrees AOA, wing rock came on quite aggressively and regardless of whether I tried flaps or spoilers, it didn't help much.

    So the extra weight further forward did get me about another 5-10 degrees AOA, but still not very close to 40 and wing rock is quite violent when it comes on.

    So I have some ideas to try, I am going to go with the SMJV2 motor after all, see if that moves my battery further forward (which I assume it will) and lengthen that "lever" even more to see if that helps. I will also put some short ESC extensions between the motor and the heavier 40A ESC so that I can put the ESC further forward as well. Although this will make the plane heavier and increase the wing load, it will be experimental depending on how this affects overall flying.

    I had hoped that building with DTF would help give this plane a bit higher top end speed as I'm flying at essentially the same weight with the same power setup as my first F-18 V5. Alas, I think increasing the width of the LERX and putting the "dogtooth" on the wing created more drag and cancelled that out. It is still fast, but no faster than my original build.

    Anyway, that is the "bad" stuff out of the way :) With the addition of the "F-18 V3ish" LERX, dogtooth and tails, it has some of the good qualities of the V3 while retaining the quickness and agility of the V5. It does however feel a little "softer" and more forgiving on the sticks. Not that the stock V5 is scary to fly, this one feels just a little more smooth on the sticks. Not by a lot, but enough that I notice the difference :)

    I certainly enjoy flying this plane in either configuration, I will be interested to see if adding the extra weight and power of the SMJV2 makes that big a difference in the flight characteristics. Never know sometimes til I experiment.

    I still haven't got my throws completely dialed in, I hope to do that tomorrow with the new setup. It does actually move equally as quick as the stock plane, perhaps just not as aggressively :)

    I should have today's video uploaded soon :)

    Cheers,

    Scott
     
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  13. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Video uploaded a little quicker than expected :)



    Cheers,

    Scott
     
  14. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    The now "hefty Hornet" ready for part two of flight trials :)
    2017-10-30 17.17.49.jpg
    My AUW is now 21.9 oz/621 gr. I'll take it easy on the G at first to ensure the wing can handle the extra weight. The SMJV2 does kick out some serious thrust with this prop which I'm hoping will compensate for the extra weight, I flew it for quite awhile on my original F-22 V5. With the battery still where I had it with the previous motor, I can still balance on my CG by moving a slightly heavier 40 A ESC about 2" further forward than where I had my 30A ESC.

    Hopefully will have the conditions to test it out tomorrow :)

    Cheers,

    Scott
     
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  15. Nightswatch

    Nightswatch Top Gun

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    Looks great Scott Can i ask you what angle did you use for canted vertical tail fins for this model
     
  16. e3_Scott

    e3_Scott Top Gun

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    Thanks very much. Angled about 20 degrees from pure vertical, to drew this little diagram for reference. Hope it helps.
    2017-10-31 16.00.38.jpg

    Cheers,

    Scott
     
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  17. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Had the "hefty Hornet" out today for some more fun :)
    2017-10-31 09.47.46.jpg
    Long story short, there was not any real improvement in high alpha performance, so I think I won't mess around much more with that. I have some theories as to why the V3 was such a good high alpha machine and this one is more challenging. Of course beyond my rather abysmal high alpha piloting skills... :( If I do feel like doing any serious high alpha, I still have my RCP Su30 V4 which is a very good high alpha plane in my experience :)

    The increase in weight didn't seem to affect the flight performance negatively at all, in fact it felt even a little smoother and has a bit better "presence" in the air, especially when there is a little bit of a breeze. Wind penetration and stability has improved a bit also. I was a bit worried about the wing holding up to the extra weight, but since I used 4mm carbon rod instead of 3mm carbon tube, the wing was rock solid, I didn't see any wing flex at all in any sort of high G maneuver, so I'm happy with that.

    It still responds very quickly in all three axes and I didn't really sense the extra 1.3 oz made it feel any "heavier on the sticks" I think I will leave it this way for now, I'm quite pleased with how it looks and flies :)

    I dialed in my throws today -

    Pitch - 1 and 1/4" travel (one way);

    Roll - 3/4" travel (one way) in both the elevons and ailerons; and

    Yaw - 5/8" travel (one way).

    In the roll, I ended up with a bit of a different setup than I normally use. On most planes, I end up with the ailerons moving about 40% of the deflection of the elevons in the roll axis.

    I tried to demonstrate what was happening in the video I will post later, not sure if I did :(. But what was happening with this ratio with this plane was often when I tried a roll, I could tell that the elevons were having much more effect than they should, causing the rolls to be "less than axial" to put it mildly, normally the nose would wander around quite a bit and the rolls felt unbalanced. So I started to reduce the deflection in the roll portion of the elevon and increase it by that amount in the aileron until I got to a point where the rolls are much more axial and balanced. I ended up with the deflection being even in the aileron and roll portion of the elevon which I found interesting, but whatever works some days, the mysteries of aviation I guess :)

    I do have another video processing, I will post that when it is finished :)

    Cheers,

    Scott
     
  18. For a guy that said his we
    For a guy that said his weather is crappy you sure have been doing a lot of flying. ;)
     
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  19. e3_Scott

    e3_Scott Top Gun

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    The weather was not that great a couple weeks ago, better now, I take advantage of it when I can. I certainly don't think I complain about the weather as much as some folks on this forum, all part of the world of aviation, you take what mother nature gives you... :)

    Cheers,

    Scott
     
    Last edited: Oct 31, 2017
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  20. Nightswatch

    Nightswatch Top Gun

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