Derek's Scratch Built 74" 3D Plane

[Derek]

Well, I think it was late 2014 when I actually started to build this plane. Obviously I got distracted by the mini quad world because I never got back to this plane, lol. Terrible!

So....here we are...a brand new year...2016...I have all the parts and pieces to finish this plane but more importantly, I have the focus to get back to this plane....finally, lol.

This plane is mostly framed up with 3/4" insulation foam board, from my local home improvement store, and some 1/8" plywood for the motor mount/firewall, landing gear reinforcement, and some structuring. I've got a 245kv Tacon Bigfoot 160 motor, from HobbyPartz.com. It's rated up to 14S lipo. I'll be setting this plane up for 12S with a Castle ICE 120HV ESC. I'll have a Spektrum 6 channel rx with satellite on board with a LiFe battery to power the receiver. I have some 10kg metal gear servos that I'll be using. One for each aileron, obviously, one for the rudder (on a pull/pull), and I'll be using two for the elevator (one for each elevator half). The two for the elevator will be set up with a mix of AUX1 and Elevator in my DX8. I have some very sturdy landing gear and wheel pants from a 68" Sbach and a steerable tail wheel that I bought from my local hobby shop. Here is a pic of the plane, as it sits right now

74 inch 3D plane.jpg (74.72 KiB) Viewed 5761 times

Quickly, you'll see that the plane is white. That white is the background for the rest of the colors, soon to be added. The wheel pants are painted white, blue, black, and silver. I decided to just color the plane to match the wheel pants. Unfortunately, the white is the ever-heavy Duck Tape. I did try using white colored packing tape but the white colored packing tape didn't cover the color of the green insulation board, at all. So, I went with the Duck Tape, instead. Besides that, in the event of an unfortunate crash, perhaps the Duck Tape will help hold the pieces together instead of exploding all over Gods green Earth, lol.

I cant get it out of my head that there is just so much material aft of the CG (wing spar) so I will be building a custom brushless motor standoff to push the massive motor away from the CG, a bit, and it will also allow me to make a better looking cowl for the nose. However, I can't decide which stand off to consider building. Let me ask the opinions of the Hangout.

plane standoff.jpg (9.2 KiB) Viewed 5761 times

plane standoff2.jpg (44.54 KiB) Viewed 5761 times

Which stand off should I be considering, or does it matter? This is a powerful motor and it will be spinning an 18" prop...maybe up to 20" prop. I have no intentions of 3D flying with this plane. Circuits and Sport flying....a few loops and rolls...that's about it.

.....more to come...

[Derek]

I just stepped out to the garage and slapped the wings on and snapped a few more pics. The wings are also made of that same insulation foam board and then bent around a thin walled steel mop handle that I got from a local discount store. I figured that mop handle would be rigid enough to be used as a channel for the 3/4" x 72" pine dowel to be used as a wing spar.

Wings on Right Angle.jpg (134.51 KiB) Viewed 5759 times

Wings on Front View.jpg (118.65 KiB) Viewed 5759 times

I need to get more white Duck Tape so that I can finish the coloring on the wings and then begin adding a bit of blue, silver, and black to match the wheel pants.

[DOG]

That's a nice little project you got going their Derek. Where do you fine the time to sleep? Looks real good Derek. Keep up the good work and the pics coming. Cant wait to see the Hindenburg up in the air.

[danhampson]

Wow I had forgotten about this build Derek , it's looking sweet.
Personally I would got with the top motor mount just because it looks far more substantial and is also adjustable letting you play with the cowl length.
I just don't like those standoff type mounts.

[Derek]

Thanks DOG! Actually, I find plenty of time to sleep, lol. I just have so many different projects going on, at the same time, I wish I had more time to get things done.

Dan, obviously I forgot about this build, too, for a while, lol. It's looking better and better each time I work on it. I have to agree with you about the motor mount. Having the adjustability could prove invaluable. I'll need to build a cowl for the plane so, I could simply set the motor mount to "short"....build the cowl...attach the cowl...then adjust the motor mount til the motor fits nicely. Sounds good!

[pvolcko]

Agree on the motor mount. Have to be careful with the weight though. That may be too much extra out front.

[Graham Lawrie]

Nice one Derek:) looking good:)

[Derek]

Agree on the motor mount. Have to be careful with the weight though. That may be too much extra out front.

There is a lot of material behind the wing spar. I'm afraid that the plane will be tail heavy. I surely won't just assume that it will be tail heavy, it's just a guess.

I'll work on the motor mount that is adjustable. It should be simple enough. Hopefully I can some time that I can work on this plane and begin to get things installed.

In the end, I have no doubt that the plane will lift off the ground. After that, well....I hope that the Pilot Gods are with me, ha ha ha.

[pvolcko]

The wheels on that look puny compared to the overall size. If you're flying off asphalt or packed dirt it should be okay, but on grass those seem like they'll get hung up pretty easily?

[Derek]

The landing gear and the wheels (including wheel pants) are from a 68" Sbach kit. I suppose I could check the wheel pants for clearance for wheels that are a bit larger. However, this plane will probably only ever fly at the flying club field with the paved runway and short cut grass.

[cml001]

Coming along nicely Derek!

[Derek]

I don't have any new pics at this time but I managed to find some time tonight to get some work done on this project plane.

I've been staring at this plane for the past few weeks and the more and more that I stared at it, the more and more I became unhappy with the actual size of the rudder. So, I made myself happy by cutting off the rudder, tracing the original rudder onto some new foam, then adding 1.5" all the way around. Now the rudder is much bigger and I think it suits the actual size of the plane better. I got it covered with white Duck tape and now it matches the rest of the plane.

I also went ahead and installed the hinges and the control horns.

I ran some 3' lengths of control rod through the sides of the fuselage for the two elevator halves.

I made two servo trays. One for the two elevator servos and one for the rudder servo and installed the servos (http://www.hobbyking.com/hobbyking/stor ... Search=hxt)

I'm going to set up the rudder on a single servo but I'm going to use a "pull/pull" system. I'm trying to keep the cost of this project down so, instead of buying a "pull/pull" system for this plane, I've simply placed a heavy duty control horn on each side of the rudder and used nuts and bolts (and locktite) to secure the horns to the rudder. I've got LOTS of 26 gauge wire available (yards and yards of it that I snatched from the recycle bin at work, lol). I'm going to use that wire as my linkages from the servo arm to the control arms. I've used this same method on my Blue Cub STOL and I just can't see this method failing.

After getting the rudder complete and set up, I installed the rudder with epoxy. NOTE TO SELF - invest in some 20 or 30 minute epoxy so that there isn't that uncomfortable rush. The 5 minute stuff is great but it would be nice to not have that "rush".

I began to look at the Castle ICE 120HV esc that I'll be using. Unfortunately, it has 8 gauge wire that will go to the motor leads. My soldering gun may need replacing because it just wasn't getting warm enough to solder 10 guage wire to it, nor the EC5 connectors. I'm either going to have to see if my Dad's soldering iron is up to the task or I may have to go to my local hobby shop and have the guy there do it for me. Ultimately, I really need to invest in a soldering station that will suit my random needs (I think we've been down that road a few times before, lol).

Now, it's nearly 3am and I need to get something to eat. The 74" 3D plane is coming along.....slowly. I began to look to the future and I began to wonder.....is this plane actually gonna fly??? I "think" so! Or, is this project plane just gonna be something that I've had fun building as something to simply occupy my time and maybe I should have just left it on the shelf? LOL...there's only one way to find out.......get it done....powered up and maiden the sucker! Maybe it will be a complete flop.......maybe it will just impress the hell out of me. Either way....I'm stoked to get the plane done!

[pvolcko]

Nice progress. Hope you get it wrapped up soon. Spring is almost here!

[Derek]

Yeah, I hope I can get it wrapped up soon, too. Even more so, I hope the plane flies....at least once. The more and more I look at it, I'm thinking that I have placed the wing spar a bit too far forward. I've been looking at pics of other 74" kits and I'm not convinced that the wing spar is in the right place. Unfortunately, because the spar mount is VERY MUCH glued in place, I'm thinking that it's gonna take quite a bit of nose weight to get the plane to balance out. Now, the plane does have this massive 245kv motor and 18" APC prop at the nose. There will be two 6S 3700mah lipos very near the nose as well as some sort of battery tray. The Castle ICE 120HV ESC will be near the nose. There will be a 2100mah LiFe battery near the nose to power the rx and servos. I'm thinking that I'm just going to continue with the build, as previously planned, and then check the CG. I'm thinking that there will need to be a motor mount built to set the motor a little more forward. Instead of buying some aluminum to fashion up a motor mount, as previously discussed in this thread, I'm just going to hack up a 2x4 piece of wood to set the motor forward and secure it in place with all-thread and lock nuts....but I won't know any exact lengths for the wood and all-thread until I get this monster finished up and check the CG.

I'm no master builder but I sure hope I can come close! Only time will tell!

[Derek]

...a bit of progress...video this time, lol...

https://www.youtube.com/watch?v=88zjSl- ... e=youtu.be

[Graham Lawrie]

Thats way cool Derek:) didnt realise how big it was until your hand came into view:)

[Derek]

Yeah Graham..its 74" wingspan...74" long. Its big!!!

[danhampson]

Looking good Derek. That thing is a monster looking forward to seeing it in the air.

[Derek]

Looking good Derek. That thing is a monster looking forward to seeing it in the air.

Thanks Dan! I'm hoping it makes it into the air, lol.

[DOG]

I agree with Dan, that's looking really good Derek. Damn, that bird is longer then me. I'm only 65" tall