FRCFOAMIES F-15 MK2

Discussion in 'FRCFoamies Plans' started by Boxermad84, Jun 18, 2013.

  1. lysle42

    lysle42 Ace Pilot

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    wow what a paint job! love the detail very clean build
     
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  2. jimbosflyin

    jimbosflyin Top Gun

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    I also have my elevons on my wing plate .Wish i had a grass field to land on,i'm flying on a fresh tild corn field so i have to plop drop.Great maiden barry, hope you feel better soon.
     
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  3. F1wanabe

    F1wanabe Administrator

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    Barry, you are a trooper! Hope you get better soon. If you have cg at stick position it should be ok on landing. In fact, since Jay and I were using the ntm prop drive, we tilted the motor DOWN a degree or two to keep nose from rising under power. I would recommend pulling cg back a bit like others have said. If you pull it too far back the plane will roll out at the top of a loop. Then I'll go further forward a tad. Good luck!
     
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  4. bogusbandit56

    bogusbandit56 Top Gun

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    Barry I think the 7x5 is for the 2826 1450 motor not for the 2826 2200. you will not be able to swing a 7x5 on a 40amp esc.
     
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  5. BarryM

    BarryM Ace Pilot

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    Hi Jimbo, I used a 7 x 5 on the SU30 because it was lying in my toy box, no science here just "I wonder if this will work"..
     
  6. BarryM

    BarryM Ace Pilot

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    Hi Bandit,The spec sheet for the 2826 2200 on 3's shows 7 x 3, don't know too much about this but I think a 7 X 5 is a little kinder, I have a 30A esc and so far o/k on the SU & F15
    2826 spec sheet.pdf
     

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  7. bogusbandit56

    bogusbandit56 Top Gun

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    The 7x5 will draw more amps and slow the motor down. I am using 6x4 on my 28262200 turnigy motor and it works well. The 7x5 is for 2cell lipo. Are you using an RC timer motor? A prop has 2 measurement 7" is the diameter of the prop and 5 is how many inches forward it travels with each rotation. It is similar to the gearing on a car gearbox, so for instance you try to put the gear box off a Chevy Camaro in a Ford Escort the engine would not be able to cope with the tall gearing. You have to match your props with the motor and ESC. I hope this helps a little. So a 6x4 prop will spin at a higher RPM giving more thrust. Some times bigger is not always better:)
     
    Last edited: Apr 28, 2015
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  8. BarryM

    BarryM Ace Pilot

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    Aaaaargh........brain freeze...:confused: someone told me long ago (there's a song in that CCR) that the pitch was measured like the thread on a screw, say a 1" x 6 =6 threads / inch, 6 turns will move the screw 1", a 1" x 10 will require 10 turns to move 1"...:( never had to doubt it but it looks like its 180deg out of phase (other way round), learning all the time. My motors are Turnigy 2826 2200 same as yours after reading your explanation I think I might just try a 7 x 3 as per their spec. 340w div by 11.1v about 30amp.:)
     
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  9. bogusbandit56

    bogusbandit56 Top Gun

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    Yes Barry, I would think the 6x4 and 7x3 are similar in performance it `s just a matter of will it fit in the plane.. Most of the guys here will help you out if you are in doubt. There is a website called Ecalc and it allows you to calculate you planes weight with what thrust prop and motor sizes etc. I dont use it myself I guess and that is why I lost my scratch built Fokker D8 that I use as my avatar:)
     
    Last edited: Apr 28, 2015
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  10. BarryM

    BarryM Ace Pilot

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    I'm more seat of the pants flying, try whatever is in my toy box, maybe time to start doing some extra homework...thanks for the info I will try the ecalc site...pity about the D8 it looked an awesome plane.
     
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  11. BarryM

    BarryM Ace Pilot

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    Had a couple injections for the flu bug...feeling much better already...:)
    Just finished fitting new elevons to the F15, after all the feedback..thank you gentlemen.....I replaced them with Mig29 style with a fixed portion on the wing plate and larger moving section 10mm added the the rear hinged along the whole wing plate and the fixed portion...oh and removed the dog tooth, it's not quite as aesthetic as the original but hopefully a bit more robust on the grass landings...:)
    33 New elevon fixed part small.JPG
    34 New elevons complete small.JPG

    Just a couple of licks of paint and it's good to go....:D
     
  12. bogusbandit56

    bogusbandit56 Top Gun

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    Glad to hear you are all feeling better and the F15 is looking slightly sukhoi, which isn`t a bad thing. Hope all goes well next flight.
     
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  13. BarryM

    BarryM Ace Pilot

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    Hi Jimbo,
    My F15 is flying quite fine but seems a little sedate using the 2826-2200 7x3 prop and 3 cell 2200mah battery, I have an NTM 2836-2700 sitting here looking at me.....what battery and prop are you using on your NTM powered F15 and whats your final flying weight with the battery??
     
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  14. F1wanabe

    F1wanabe Administrator

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    Our prototype has a 6x4 apc which is perfect for the NTM!
     
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  15. jimbosflyin

    jimbosflyin Top Gun

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    I'm useing 2200 mah batteries 30c with 6x4 props,i no longer have my final weight sheet for this plane but i think it was just under 23 oz. with 3 servo's.Have you tried a 6x4 on yours ?
     
    Last edited: May 30, 2015
  16. BarryM

    BarryM Ace Pilot

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    Tried a 6 x 4 with the 2826-2200 not enough, flies best with a 7 x 5 but think the NTM with a 6x4 maybe the answer...My flying weight is 767g (27oz), I have a couple of Nanotech 2200mah 25-50C in the toy box with a 60A ESC...probably give that a go..
     
  17. sirskyhi

    sirskyhi Ace Pilot

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    Just finished the F-15 MKII build, now ready to paint and add the electronics. I cut the elevators so that the leading edge is secured and hinged so to eliminate the leading edge from getting caught in the grass and mounted then on the upper portion of the tail. This is another one of my favorite planes and can't wait to fly it. Took out the P-51 today but I got too windy to fly. Maybe next week I'll fly both.

    F-15 MKII5.jpg
     
    Last edited: May 30, 2015
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  18. sirskyhi

    sirskyhi Ace Pilot

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    I'm having problems getting the F-15 MKII to balance at CG. I have an AUW of 28 oz using a 1800mAh 3s battery and a 2700kv motor. With this and the ESC and receiver my plane is really nose heavy. Any ideas how I to get this to CG? Am I missing something?
    Painted F-15.jpg
     
  19. F1wanabe

    F1wanabe Administrator

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    Wow, very strange! Did you fill the nose with any filler? The ntm is so heavy I used a 2200 up front to balance out. Are you sure the cg is marked properly according to plan? The cg should fall close to where KFs intersect.
    [​IMG]
     
  20. jimbosflyin

    jimbosflyin Top Gun

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    bring your battery closer to your motor if you haven't all ready done so and place your esc on top of battery and hold in place with velcroe. Show a pic of your set up.I don't know why it would be that far off.
     
    Last edited: Jun 2, 2015
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