FRCFOAMIES F-15 MK2

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

  1. e3_Scott

    e3_Scott Top Gun

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    Thanks, Dave, I hope to get it done this evening or tomorrow morning before I fly it. Forecast looks a little sketchy for flying tomorrow, but I hope to get the "Thunder" unleashed shortly! I will try to go into a bit more detail on the basic build process as well as a few of my mods and build techniques in the video, might not be the most exciting thing to watch, but hopefully there will a few nuggets that will help some other folks out.

    Thanks again for the kind words!:)

    Cheers,

    Scott
     
  2. e3_Scott

    e3_Scott Top Gun

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    Hi everyone -

    As mentioned in an earlier post, here is a walkaround/build video discussing some of my build techniques and mods on made on my recently completed FRC F15 MK2:cool:



    Cheers,

    Scott
     
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  3. Airflow

    Airflow Top Gun

    Nice Video Scott! :) It looks great!
     
  4. e3_Scott

    e3_Scott Top Gun

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    Thanks Airflow, some snow falling right now...:(, so might be a couple more days still before I get a chance to maiden.

    Cheers,

    Scott
     
  5. Airflow

    Airflow Top Gun

    Yeah.. :( Suffering the same bad weather this weekend scott ...
     
  6. e3_Scott

    e3_Scott Top Gun

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    Yes, and I also realized while out walking my dog in the snow this morning that since my ESC is on the bottom on my F15 and exposed, I will have to wait for the field to be pretty dry before trying a landing, have learned the hard way snow and/or standing water and ESCs are not good friends...:eek:

    But I am sure this plane will be well worth the wait, so I can be patient and fly other "beater" planes until conditions are just right...:)

    Cheers,

    Scott
     
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  7. Airflow

    Airflow Top Gun

    Yes ESC's and snow is probably not a good combination, I have my 80A ESC mounted on the belly.
     
  8. e3_Scott

    e3_Scott Top Gun

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    Hi everyone -

    I finally got out to get the maiden flight done and start dialing in my FRC Foamies F15 MK2 today:)

    2014-03-04 10.05.02.jpg

    Even though there was still snow on the ground and I was worried about my ESC getting wet, my trusty friend transparent duct tape once again came to the rescue!:D

    2014-03-04 11.32.25.jpg

    I wasn't too worried about it overheating as the temperature when I was flying was only 3 degrees Celsius/37 Fahrenheit, so the duct tape worked awesome and kept the ESC nice and dry:)

    This plane is unbelievably solid and smooth, WOW is really all I can begin saying. I thought the F15 MK1 was solid, but this plane is unbelievably rock solid in it's handling. It tracks like it is on rails, responds exceptionally well to throttle and control inputs, loses no energy in the turns with at least 50% power, no nose drop at all, just a truly beautiful plane to fly.

    Right from first launch, I had to put in one click of nose up in the pitch and a couple clicks of trim to the right in the roll (to counteract torque roll) and it was rock solid after that. I will keep tweaking it a little bit more to see if I can zero out my trim completely, but for all intents and purposes, the CofG per the plan is bang on, maybe 1/8 to 1/4" behind plan for me, but negligible difference really.

    I was a bit worried with the extra lift of the body that zooming at full throttle might be a problem, I had to do some tweaking on my F15 MK1 by tilting the motor down quite a bit to keep the nose buried, but no problem at all with this one...:) It just buried the nose and zipped right along, no torque roll at full throttle either, it stayed exceptionally stable at speed. I did a few speed runs and ended up with very respectable results 74/76/77 and a top speed of 79 mph clocked on my HK Data logger app on my phone. Seeing how stable it stayed at top speed on 3S, I am excited to see how it will move along on a 4S...:cool:

    I played around with the throws and expos a little bit, but found the following settings allowed me to fly very smooth and scale while still having plenty of control authority for tight rolls and turns when I wanted them.
    • rudder - 50% expo, 75% throws;
    • elevator - 55% expo, 85% throws; and
    • aileron - 60% expo, 70% throws.
    Because I have elevons and ailerons working together in the roll axis, I like the expo a little higher and the throws a little lower to allow my turns to stay smooth yet responsive without the tendency to overbank. These settings allowed me to do beautiful smooth loops with just over 50% power and about half stick pull back, it rolls exceptionally smoothly, no nose or tail wobble, once again, just rock solid handling.

    With the extra lift of the body, this plane flies much lighter than I expected, which is a good thing...:) The extra lift provided by the body reduces the wing loading, making it feel lighter and more responsive than other planes I have flown at this weight, one of the reasons I think it feels almost effortless to fly this plane smoothly and solidly.

    I am sure with a lighter build than what I did that this plane would fly just great with a lighter power setup, but in my humble opinion it is just one of those planes that deserves that extra raw horsepower that an NTM Prop Drive provides...but just my humble opinion...:cool:

    It is also one of the coolest sounding planes I have ever flown, with those long intakes/nacelles, it makes a cool whistling sound even at half throttle, so it sounds really impressive at full throttle or in a high speed power dive, it literally screams as it hits top speed:D.

    All the mods and reinforcements I made worked out well, I was worried with the battery so far forward to get CofG that it would feel nose heavy in the pitch, but no such feeling or tendencies at all. The wing stayed rock solid, no wing flex that I could notice. I didn't really explore any slow flying today, although it did "waffle" a bit in turns when there was a little breeze if I let my speed get down. I found pegging it at 50% throttle allowed me to cruise around very nicely, it kept it's energy up beautifully and as along as I didn't bank and crank too aggressively, I was fine all day long at 50% throttle.

    Lots of rudder authority as advertised, even with the throws I had, I hit full rudder going vertical and it did kind of a "rudder roll" where the nose stayed where it was and the tail flew kind of a circle, looked like a bit of a corkscrew type thing, not exactly scale, but it did allow me to some kind of slow hammerhead/stall turns with the nice rudder authority.

    So overall, smooth, solid, no bad habits or tendencies that I have yet to discover, just an amazing scale looking and flying F15 parkjet! Great job FRC Foamies:)

    Flight video is being processed as I write this and should be posted later today!

    Very, very happy with this plane and that I got to unleash the F15I "Thunder" today...:cool:

    Cheers,

    Scott
     
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  9. e3_Scott

    e3_Scott Top Gun

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    Hi everyone -

    As promised, here is the flight video I shot today of my FRC F15 MK2. I apologize that it isn't the sharpest video quality:rolleyes: although it seemed to be sharper at the end than it was a the starto_O

    Anyway, as I said above it flies beautifully and there is just something about a planform of an F15 in the sky that says "Air Power", at least in my humble opinion...:cool:



    Just an awesome plane...:)

    Cheers,

    Scott
     
  10. Boxermad84

    Boxermad84 Administrator

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    Awesome, Scott! What a great review, not only does it look good, it performs good to! Thank you for building and sharing your thoughts with us all. Amazing!

    Sent from my galaxy note 3 using Tapatalk pro
     
  11. e3_Scott

    e3_Scott Top Gun

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    Thanks, Jay

    Cheers,

    Scott
     
  12. e3_Scott

    e3_Scott Top Gun

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    Hi everyone -

    I managed to get out to the field yesterday and get in another 9 flights on my FRC Foamies F15 MK2 before the rain started up again... :):(, (happy to fly, sad it started raining)

    Through my You Tube channel I have had a couple of questions on how I feel this plane compares to the RC Powers V3 lineup. Tough question to answer really as each plane is unique in it's characteristics and I have thus far only 18 flights on my F15 and 250+ flights each on my F18s and Mig29s. I have also not had a chance to fly the F15 in any sort of windy conditions to evaluate it's performance there. I also have not flown the F15 very much below 50% throttle nor have I tried any high alpha with it, but I haven't seen too many real F15s do a lot of high alpha, so I'm not sure that is a flight regime I will explore for reasons explained in the next paragraph. I won't compare it to the RCP F22 V3 as that plane is kind of in another category, not bad, just more challenging to set up and fly correctly and less forgiving than the Mig, F18 or FRC F15 by far.

    I should caveat that as of late I have been trying to fly my planes more scale (ie more like the real thing). Thrashing a plane around doing flips, tumbles and crazy aerobatics is a lot of fun, don't get me wrong and is one of the reasons I recently built another RCP Mig29 V1, but I find that trying to fly my planes more smoothly and in a more scale fashion is a great challenge and actually gives me a much better feel of how my plane is flying and responding to inputs. So what I am about to say is based on personal opinion and flying style. In truth, I love flying all three of these planes, each for their own characteristics, but perhaps you have already flown the Mig29 and F18 V3s, this might put the FRC F15 MK2 in context depending on what sort of flying experience you might seek. Or if you are looking for an alternative plane not in the RC Powers V3 lineup, perhaps this will help.

    So, where do I start? Well, I do fly a Mig29 at almost the same weight as my F15, so I will compare those two, they both have the same power setup (NTM Prop Drive 2700 with a 6x4 APC prop) and all the same control surfaces (elevons, ailerons and rudder). The F18 unfortunately is much more weight sensitive and when I tried to fly my first F18 in the 25-26 oz range, bad things happened...broken wing, horrible death spiral...blah, blah, blah...:oops:

    So perhaps because of the lighter weight, the F18 V3 feels just a little more floaty than the F15 and the heavier Mig. Not floaty in any way that in my opinion is detrimental to flight characteristics, but rather makes it very easy to handle at low speed and in high alpha. The F18 in my humble opinion is a great second plane after say the F35 if you are just getting started as it's handling and tracking are still amazing, but since you really need to build it light to keep the weight and wing loading down, it will be "floatier" in comparison to the Mig and the F15 and therefore give you a little more time to react to a situation. Plus as I have written in the F18 V3 thread of this website, it almost has self correcting tendencies without the benefit of on board stabilization. Also I find that with the right weight and power setup (I like to fly mine around 21.5 oz with the Focal Price 2700 motor with a 6x3 EMP prop), the F18 can be very responsive and aerobatic but is never going to be a speed demon.

    The Mig29 could also be a good choice for a second plane if you are just learning, but I would keep it light with low wing loading to make it a little easier to handle and then work your way up if you want to get it going fast and more scale. The Mig29 V3 of all the parkjets I have ever flown is by far the most flexible from the standpoint of weight and wing loading, proven by several people to fly well from 15 oz to 40+ oz with very light setups like the MJV2 all the way up to huge powerful 6 cell setups. The Mig29 built at a heavier weight and with the higher speed of a big power setup might make it a bit too challenging if you are still learning in my experience. Not that this is a bad thing, but the difference between my lighter Mig at 21 oz with a 2200 battery and my heavier Mig at 25 oz is significant in the feel I get in the sticks when flying aerobatics and turns, more stick travel and pressure required for the heavier Mig than the light Mig (and the F15 for that matter). Even at 25 oz and a heavier feel on the sticks the Mig does feel just a little more agile than the F15, but again, just my humble opinion.

    The F15 MK2 would probably be a good choice for maybe a third plane, not because it is difficult to fly, but it is a bit more advanced and challenging build than both the F18 and Mig29 V3s. In handling, the F15 tracks maybe even a tiny bit better than the heavier Mig29 (again just my opinion), yet it feels much lighter on the sticks. The extra lift from the body of the F15 makes it feel more like my 21 oz Mig29 rather than it's 26 oz AUW. Not sure if that makes sense, but if feels and handles like a lighter plane than it is. The weight and wing loading still keep it exceptionally stable and smooth, but not as much input required to maintain the same amount of turn rate as with the 25 oz Mig. I have yet to find any bad habits with the F15 MK2 and not only does it look very scale, it flies very scale as well (at least in the setup I have). In the regimes I have flown it, I would say it is the most scale looking, feeling and stable yet responsive (not as responsive and agile as the FRC Su jets of course...:cool:) of all the FRC Foamies planes I have built and flown (again, my opinion, I have built and flown the F15 MK1 in 100 and 120% sizes, Su37 MK1, Su37 and Su35 MK2s and the F35 600).

    As I said earlier, I love all three of these planes for their own unique characteristics, but boiled down, here is how the F15 compares in my opinion -
    • tracks and handles a bit more smoothly than both the F18 and Mig29 V3s (Mig29 is very close);
    • doesn't handle quite as well at slow speeds as either the Mig29 or F18 and a little bit less agile than the Mig29;
    • with the extra lift of the body, flies lighter than it is, lighter than the Mig29 of comparable weight;
    • it is fast, very close in speed to the Mig29, I'm excited to see how it handles 4S;
    • more challenging build than the F18 and Mig29, good choice for maybe a third plane if you are just getting into the hobby and are still learning to scratch build; and
    • in my humble opinion, it really deserves a heavy power system like the NTM Prop Drive 2700, you could build much lighter I'm sure and use a lighter power system, but some planes just deserve some good old raw horsepower and I think this is one of them...:cool:
    So if you are looking for an amazing looking and amazing flying classic US designed and built fighter jet to add to your hangar, the FRC Foamies F15 MK2 would make an excellent addition in my humble opinion...:)

    Cheers,

    Scott
     
  13. charles52

    charles52 Cadet

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    e3Scott,
    I have been following your blog and utube videos and you mention the ntm 2700 motor as being one of your favorites. Being new to all this some of the lingo is making me a little crazy. Could you tell me what NTM, APO pro, EMP prop stand for? Also after building my first RCP F35V3 I am getting a weight of 12oz. without electronics and hardware, and with those it should be around 23oz ready to fly. I realize I am getting to the upper limit of the recommended weight. This weight is with the Grayson hobby mjv3 and a 1800 3s battery. Would going with a ntm 2700 give me any advantage over the 23oz total weight for flight characteristics? All of these acronyms are killing me.
    Charles52
     
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  14. e3_Scott

    e3_Scott Top Gun

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    NTM, APC and EMP are simply brand names. I'm sure that NTM stands for something, but suffice it to say it is a brand name line of motors distributed by Hobby King.

    APC stands for Advanced Precision Composites, their website is here http://www.apcprop.com/v/index.html I buy the APC style props from Hobby King, they are cheap and work well for me http://hobbyking.com/hobbycity/store/uh_viewItem.asp?idProduct=22423

    [​IMG]

    EMP stands for Electric Model Power which is a brand name. These similar propellers I believe are also sold under the TGS brand name at Hobby King. I buy my EMP props from RC Timer as they are the best deal I have found. http://www.rctimer.com/product_218.html

    [​IMG]

    I would say if you are brand new to the hobby, the NTM Prop Drive is not a good choice for your F35 V3 as it will make your plane even heavier and therefore harder to handle especially since there is a lot of power to keep under control with that motor as well.

    I have bench tested the MJV3 motor and flown it on a lightweight F18 (17.7 oz). So if your plane weighs 23 oz after you are done adding all the components, your thrust to weight should be between 0.8 and 0.9:1 which theoretically is enough to get your plane flying and keep it flying, but you will not have a lot of extra punch out or acceleration for aerobatics.

    The RC Powers recommended motor, the Turnigy D2826/6 motor is 14 grams heavier than the MJV3, but puts out about 26 oz of thrust, works well with a 30A ESC and the same battery you are using.

    The NTM setup would add about 4.3 more oz to your plane and you would probably have to upgrade to a 2200 Mah battery, so again, I would avoid that for my first plane.

    My best advice to you is not to worry about it too much, unless your plane ends up really heavy, like say up around 25 or 26 oz when all finished, just try it with the MJV3 first to see how it goes. You will have to use fairly high throttle settings to get and keep it flying which will shorten your flight endurance. If you find you have to fly at full throttle all the time, then it might be worth thinking about upgrading to a more powerful but still fairly lightweight motor.

    So if you are new to the hobby, I would say no, the NTM Prop Drive 2700 is not a good choice for you for your first plane, too much weight and too much power for when you are learning. Try your plane with the MJV3 first, then you can look at the attached spread sheet to see what motor might be a better option, there are lots of other motor options for V3 size planes than the NTM Prop Drive 2700, I tested 8 of them on my testbed F18 V3 that you probably saw on my youtube videos. I have also attached a file showing weights of all the components I use when building, it allows me to be pretty accurate in predicting the final weight of my plane.

    I hope that this has taken some of the mystery out of it for you. As you can see from the pictures, the APC props and EMP props are shaped differently, the APC prop is more aggressive at the hub while the EMP prop is more gradual. A 6x4 APC prop is good for speed, a 6x3 EMP better for torque (acceleration and punch out which are good for aerobatics). The 6x3 EMP props do normally have to be balanced to work properly as they are notoriously out of balance from the package, the 6x4 APC props not so much.

    Good luck with your F35:)

    EDIT: I just read your and my posts again, Charles. The Focal Price 2700 motor is definitely a favorite of mine for these V3 size planes. I use a 6x3 EMP prop on that motor and a 40A ESC, gives great thrust and amazing pop and acceleration. I bench tested it at producing about 36 oz of thrust. The stats on the motor are on the attached spreadsheet, here is the link to it http://www.focalprice.com/YO090X/A2212_2700KV_Outrunner_Brushless_Motor_for_Airplane.html I also started a thread on it here at the RC Powers website http://www.rcpowers.com/community/threads/focal-price-2700-kv-parkjet-motor.15992/ which should give you more info on what you need to use the Focal Price 2700 motor. The NTM Prop Drive is also a good motor, but for more specialized use, the Focal Price 2700 motor is a better all round choice for V3 size planes in my humble opinion.:)

    Cheers,

    Scott
     

    Attached Files:

    Last edited: Mar 7, 2014
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  15. F1wanabe

    F1wanabe Administrator

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    Catch it, Scott! We've been snow covered here for months- can't let that stop a good flying day! I wonder why you needed to tilt the motor down so much? I put ours at -2 degrees which is standard procedure for any plane I intend to fly fast. Learned that one from JettaManDan. I wonder if your rudders are pulled in a little causing the nose up with throttle? The elevons look OK. Something is not right if you have to put that kind of angle on it.
    The F15 should be as stable as the Mig at slow speed, and the f15 rudders are actually more effective at slow speed. The lifting body is the main difference between the two and is why the F15 feels lighter than the mig. That can be used to your advantage with lighter power set ups too as the lifting body has less drag than lift from the wing, so don't feel you need to use the NTM. Lower wing loading feels great on this. Good work!
    PS. I like the summation at the end- very succinct! My lower attention span appreciated it!
     
    Last edited: Mar 7, 2014
  16. e3_Scott

    e3_Scott Top Gun

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    Charles -

    In my post above, I forgot to add the link to this page, I still go back to it often to read and learn and it is a gold mine of information in my humble opinion

    http://www.rcpowers.com/community/threads/resources.10941/

    I also learned quite a bit by listening to this podcast a while back from Flitetest http://www.flitetest.com/articles/flitetest-podcast-003-brushless-motors-and-lipos

    I have found one of the great things about this hobby, especially scratch building is that it is a constant learning process, often by mistakes I have made (which sometimes is the best way to learn) or from mistakes others have made and are brave enough to share (which makes forums like this so great) or just from poking around the internet.

    Good luck!

    Cheers,

    Scott
     
  17. e3_Scott

    e3_Scott Top Gun

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    Just to set the record straight so others don't think there could be a zooming problem with the F15 MK2, the problem I was referring to was with my F15 MK1 as I posted in my post flight report in post #188 above. I have the motor dead center on the F15 MK2 and have had no problems with the nose involuntarily pulling up at high speed.

    Cheers,

    Scott
     
  18. F1wanabe

    F1wanabe Administrator

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    Oh, I see Scott. I apologize. I do 90 percent of the forum viewing on Tapatalk and on longer posts like that I sometimes miss content while scrolling down. That's why I appreciated the quick summation at the end of the other post! ;-) I'll try to reread it all tonight on the computer.

    www.youtube.com/gstrysky
    www.frcfoamies.com
     
  19. charles52

    charles52 Cadet

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    e3Scott,
    Thanks for all your help. BTW I enjoy reading and watching your video reviews etc. I am particularly impressed with the level of attention to detail that you, F1wanabe and others give to this. It is a wealth of info for us beginners
     
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  20. e3_Scott

    e3_Scott Top Gun

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    No problem Charles, you are most welcome, thank you for your kind words, glad to be of help. Best of luck with the maiden of your F35 V3:)

    Cheers,

    Scott
     
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