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FTFC19 Don Karnage Triplane - TailSpin designed by Horseman3381

Horseman3381

Well-known member
#1
Hello all, here is my foray into the 2019 Flite Test Fantasy Plane Challenge, Don Karnage’s Triplane.

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One of my favorite TV shows growing up was Disney’s TailSpin. I partially attribute it to my current love of airplanes and directly attribute it to the reason I Fly RC. I have friends that have been flying RC for years. I was always hesitant to get into the hobby due to the cost. When they would ask what it would take to get me into flying I would tell them “When someone makes an RC Sea Duck, then I will start flying”. So a little over 2 years ago when I discovered Flite Test and they released the FT Sea Duck, living up to my word I got into the hobby with the Sea Duck being my first plane.

Ever since I started flying the Seaduck I have wanted Don Karnage’s plane so me and a buddy could fly them together. After 2 years or so and having a number of designs under my belt I decided the time has come to make it happen.

I started work on this project a few weeks ago and decided to build it using the FT C Power Pack and a 10” prop which will allow the fuselage to be approximate 5” in diameter. Below is a schematic layout of the version 1 plans I drew up.

TSPP-02.jpg


The stats of the plane are:
  • 1’-10” wingspan
  • 5” diameter fuselage with a 1’-8 ½” overall plane length.
  • Construction Materials:
    • 4 sheets of foamboard
    • 3 paint sticks
    • 12+ bbq skewers
    • FT Firewall
    • 9 FT mighty mini control horns
  • Flite test C-Pack w/ 2200 mah battery
  • 11x4.5 prop
  • 3 - 5g servos
  • 2 - 9g servos
  • 5+ channel receiver
  • Radio capable of being programmed to run dual elevators
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TSPP-01.jpg


There are several challenges with this plane, the biggest being that when designing a bi-plane you generally want to have at least one wings chord length (depth of wing) between the wings. In this design I am using a wing with a 5” chord and the layout only leaves a 1 1.4” gap between each wing. This means that each wing will not be able to achieve its optimal lift potential.

I started this project 4 weeks ago. I was able to get the plans drawn in a few days, and the plane build over the course of a week after that. Then after waiting 2 weeks for the weather to clear I finally got the plane out to the field this past weekend.

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Initial flight test were done by setting it on the pontoons and running it down the runway. This was not terribly successful as the pontoons would either stick and it would nose over, or it would go down the runway, go straight vertical for 5 feet and nose dive to the ground. After the first day of testing me and some flying buddies determined the plane was tail heavy. I took it home and made some modifications to be able to put the battery further forward.

The next day after moving the battery forward we decided to try hand launching the plane. I was able to get several short but controlled 20’-30’ flights out of it, however the plane was still tail heavy and seemed to be lacking in power. We were about to call it a day after breaking the last prop I had brought (10x4.5), when another guy at the field said he had a spare 10x7 prop we could try.

Desperate to get it flying I decided to give it a go. I put the prop on, tore off the pontoons and gave it a go. With this setup the plane now had the power it needed to fly, however it was still tail heavy. I was able to do a lap of the field with the plane at an 85 degree angle. Though this doesn’t sound that successful it proved the plane had the power to fly, and was controllable.

There was only 1 thing left to do, push the battery forward as far as I could so that it was touching the front of the plane and give it a toss.

IT FLEW!

Not only was it flying, but it flew relatively well. It was a little squirrely, but very controllable. Anything short of 7/8 throttle and it started to fall like a brick. But at full throttle I was able to do 6-7 laps of the field (approximately 2 minute flight).

Now came the dreaded problem that has caused many of my planes to crash…. Pilot Error. I was lining the plane up to bring it in for a landing. I took it out a little farther to give me time to bring it down. However when making the turn to bring it in line with the runway I lost orientation and dove it straight at the ground. Fortunately I had high rates on and I was able to pull the plane up so it pancaked instead of nosing in. In the process of this rather impressive STOL landing I managed to break the last prop we had.

BUT IT FLEW!

TSPP-05.jpg


I do not have any flight video because after the 15th or 20th attempt to get it flying we decided to stop taping. When it finally made it in the air, we didn’t have our phones or camera on us. Though the plane was/is still flyable we were out of props, so unable to get it up again.

I learned a lot from version 1 of the plane, the biggest being where the CG needed to be:
TSPP-06.jpg


The next step is to make the following modifications to the plane for version 2:
  • Relocate battery hatch to the bottom to allow better installation of battery in the appropriate location.
  • Modify the pontoons to have concealed wheels in the bottom for runway takeoff.
  • Design an air duct into the plane to locate ESC in to help with cooling due to over-proped motor.
  • Attempt to reduce the weight of plane by eliminating unnecessary internal structure.
  • Lengthen wingspan by 1 ½” in attempt to get a little more lift out of them. (This will still allow the 3 wings to fit on a single sheet of foamboard)

It will be a few weeks before I have time to get Version 2 built, but I am hoping to get a few more flights out of version 1 this weekend and get some video of it.
 
Last edited:

wilmracer

I build things that fly (sometimes)
Mentor
#6
This is fantastic! I started reading your post thinking "this is VERY ambitious and I love it"... then I scrolled down and realized you had already built it... scroll further and it has already flown! That is an awesome way to start a thread. Can't wait to see her painted up and on camera!

Maybe lengthen the nose a bit on V2 and slap a bigger motor on it. If she wants the nose weight might as well make it useful :)
 

Horseman3381

Well-known member
#7
This is fantastic! I started reading your post thinking "this is VERY ambitious and I love it"... then I scrolled down and realized you had already built it... scroll further and it has already flown! That is an awesome way to start a thread. Can't wait to see her painted up and on camera!

Maybe lengthen the nose a bit on V2 and slap a bigger motor on it. If she wants the nose weight might as well make it useful :)
Thanks!

When I was first designing it I was thinking about lengthening the nose, but at the time was worried about it being too nose heavy. I guess I just had that stuck in my head, but you are right. Where it currently sits CG wise that would not be a bad idea.

As for the bigger motor, I have a spare motor that can swing a 12x6 prop on a 3s or 4s battery and I am planning to put that on Version 3. For the version I enter in the build off I want to see if I can get it to reliably fly on the C-pack setup to more conform to the competition guidelines.
 

PsyBorg

Wake up! Time to fly!
#8
Impressive!!

I first thought if this flys at all it would have to be a speed deamon with then stubby wings.

As Wilmracers said I was surprised the further I read specially when it flew.

Congrats mate thats a huge jump in pilot and build skills in that shirt time.

Looking forward to video on this.
 

Horseman3381

Well-known member
#10
Little off topic, but that edge looks amazing!
Thanks!

When I first took it to the flying field I got some crap from a few of the people there asking me "What warbird is that?" since I mostly fly warbirds. So I decided to paint it to resemble an F4F and I call it my F540

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Back on track, I was able to modify the pontoons on Version 1 of the Triplane to have wheels in them. I am hoping to be able to get runway takeoffs with this arrangement. If they end up adding up adding too much weight/drag to the plane I will remove them till version 2.

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rockyboy

Skill Collector
Mentor
#11
Awesome work on this! :D

Don't forget to post in and watch the main challenge thread for news and updates on the challenge and links to all the other participants projects. I added you to the challenge roster, but only found your thread by accident tonight :oops:
 

Horseman3381

Well-known member
#12
Awesome work on this! :D

Don't forget to post in and watch the main challenge thread for news and updates on the challenge and links to all the other participants projects. I added you to the challenge roster, but only found your thread by accident tonight :oops:
I thought I had posted in the thread, but it may have been the wrong one as I see there are 2 threads related to it. I am post #117 in this thread.

Let me know if I posted in the wrong one and I can repost.

Thanks

Also, got some flite footage last night, I will try and get it edited and posted later tonight.
 

Brett_N

Well-known member
#13
Love it LOL - I need to build another SeaDuck (the first one melted in the sun....hot glue and Phoenix Summers don't go together so well) When I do I'll build this as a battle buddy.
 

rockyboy

Skill Collector
Mentor
#14
I thought I had posted in the thread, but it may have been the wrong one as I see there are 2 threads related to it. I am post #117 in this thread.

Let me know if I posted in the wrong one and I can repost.

Thanks

Also, got some flite footage last night, I will try and get it edited and posted later tonight.
My mistake - you absolutely posted in the correct thread (and correct format) and I missed it completely. :eek:

Very glad to have you in the list now :D
 

Horseman3381

Well-known member
#15
Here is some video from the 2nd day of test flying. I was not able to get as good of a flight as the last flight I got on the first day.


With a better pilot (and camera person) this probably would have been a more exciting video. I have a few more minor changes to make to the plans for version 2 before I start working on it. I hope to have V2 ready for test flying within the next 3 weeks.
 

Horseman3381

Well-known member
#16
I was able to get Version 2 out little over a week ago. It flew better than version 1.


Version 2 had the following changes from version 1:
  • 4" added to wing span to bring it to 2'-0"
  • Fuselage nose lengthened 1 1/2" to help get CG forward
  • Updated Venting in nose of plane to help with Motor cooling
  • Moved Battery hatch from Top of plane to Bottom
I got 4 test flights out of the plane without it suffering anything more than a few dents and dings, though still haven't truly "Landed" it yet. When flying it you need to use a lot of rudder and counter aileron to keep it banking as little as possible or else it falls out of the sky. Version 2.1 will have a larger tail to help smooth our the turns and hopefully cut back on the rocking the plane tended to do.

I also have Plans for a version 3 where I should be able to cut out 25% to 33% of the plane weight. I am hoping this will allow a smaller battery to be used as well. However the concern with this is that the plane will be much fragiler. But with the impacts Version 1 & 2 shrugged off I think there is some strength to spare.

I have also added pontoons and a larger tail to "Plan B" (Bi-plane version, see the video) and I am hoping that will help it fly. If it still rolls too much I may try it with a B-Pack motor.

Winter is upon us up here in Minnesota, so flying days a few and far between. Once I get a decent weather day I will get version 2.1 back out for another round of test flights.
 

rockyboy

Skill Collector
Mentor
#17
Awesome progress! I love the way it looks, and I think you're on the right path with the proposed mods for the next version. :D
 

DamoRC

Elite member
Mentor
#19
Great job! (y)(y)
(Not only designing/building, but shaming me into getting my butt in gear!) :LOL:
^^ Yep ^^

@Horseman3381 - excellent work. That was a lot of fun to watch - she's a tough little bird that can take the hits. Any thoughts on just scaling her up a little in an effort to calm her down?

Looking forward to more.....

DamoRC
 

Horseman3381

Well-known member
#20
^^ Yep ^^

@Horseman3381 - excellent work. That was a lot of fun to watch - she's a tough little bird that can take the hits. Any thoughts on just scaling her up a little in an effort to calm her down?

Looking forward to more.....

DamoRC
I have done some looking into it. The problem is the diameter of the fuselage is so large that if I scale it up it would mean needing a larger motor and Prop. I do have a spare 850kv motor that runs on 6s and spins a 16" prop that I may put on a 150% version some day.