!00" Foamboard Specter V2 Build Log


Senior Member
100" Foamboard Specter V2 Build Log

First off I'd like to thank Flitetest for introducing me to building foambaord planes, IBcrazy for the original design, spencer for transferring it over to foamboard and creating plans, and Ed from experimental airlines for his ideas of the armin wing, and removable wing spar. You guys rock!

Skip the first two paragraphs to get to the build, just me yammering.

Little back story to set the scene.

This past summer my friend and I had some rather long talks about how we always wanted to fly rc planes as kids, but our parents wouldn't let us(in their defense this was 20ish years ago, electric was pretty bad, nitro was pricey and involved), and how after awhile the idea kind of faded. With that desire reborn and no parents around to tell us no, off we went to our local hobby shop, 30 minutes later we're out the door with our brand new Hobbyzone Glasair Sportsman. We rushed back to my house, slapped the battery in the charger, and desperately built the plane as fast as possible. An hour later we sped off to the closest field to introduce our beautiful new plane to someone I'm sure everyone here is all to familiar with, the ground...they then continued to meet over, and over, and over again. Fearing we were going to cause irreparable damage to our new toy, we eventually called it quits for the day.

That night I scoured the web looking for tips on how to not suck at flying rc planes, that's when I stumbled across flitetest. 2 weeks and all of their episodes later, as well as alot of Ed's from EA my journey truly began. That is where I learned of this lovely medium we call DTFB, I was in disbelief that something so cheap could possibly be made into a flight worthy craft, with just a bit of hot glue and some random odds and ends. Just the thought of a $5 air frame pretty much was the game changer that kept me in this hobby that I now love so much. Roughly 15 homemade airplanes later and here I am. So seriously once again, thank you to everyone I mentioned before, and everyone else in this community, for selflessly sharing your ideas, your time, and your passion, making what we do so much more than a hobby. Now enough with the mushy stuff, on to the build!!!

Since I first have been able to "fly", I've wanted something huge to put in the air, but really lacked the skills or the understanding to do so. After about 15 other foamboard planes I've decided to give it a go. I just built the specter v2 a few weeks ago for my fpv rig, and just fell in love with how it flew. Unfortunately a radio brownout caused it a tragically early demise, so yesterday I decided to build another. Today looking at the new specter and the huge pile of DTFB I had sitting next to it, I figured what the heck, snowstorm coming in tonight, I have nothing to do tomorrow, let's build a huge specter. Off the brainstorming went, a bit later I knew how I wanted to go at it. Decided to go with Ed's design of the removable wing spar, so I can fold this monster in half, just to entertain the idea of being able to transport it. I also figured just doubling the 48" version would make the measurements nice and simple. After taping my 3 pieces of foamboard together for my first wing half, I realized that I had a 50inch length, so I just decided to bump the total wingspan to a nice clean 100 inches.

I started off by taping to pieces of foam board together length wise., followed by a third piece with it's long side taped to the first two pieces' short side. Drew on my marks for my score cuts, and ended up with this. (Sorry for the crappy pics, all I have is a cell phone to shoot with.)


I then did the same thing for the other side. Next I cut my double bevel on the leading edge fold, I also cut some foam spars that started 1 inch tall and tapers to half inch over the 50 inch span. Next I fitted the two 36 inch 3/4 inch OD, 5/8 inch ID aluminum tubes I was to use as my guides for the removable spar, by removing part of the foam spar.


I then glued in a two foot section of 5/8 inch wood dowel to the wingtip side of one wings aluminum tube, as well a 2ft section of 3/8 inch dowel on the inner section of both wings to add a bit more rigidity. This worked well since when I folded the wings over that dowel got sandwiched in there nicely.


Next is where it got tricky, applying hot glue to 2 50inch segments and one 36inch before any of it dried. Mission accomplished and I got both wings successfully folded over. Next was time to install the removable spar for a test fit, and for me and my kitty to gawk at the size of it.


Little bro hopping in for some camera time.


Next I cut out the tail section, nothing crazy there, doubled the dimensions, doubled the foam board thickness, doubled the fun???


Finally to end the evening, I decided to do a quick mock up with the booms just laying under the wing section, more to once again just take in the enormity of this thing. Current weight is at 1560 grams for the wing section, tail section, and booms.


That's all I have for today, nothing to crazy really, I just think the size is pretty awesome. I plan on building the fuselage tomorrow, and then ordering the electronics after I make a good estimate on it's final weight .

Quick question for anyone who happened to read this far, since this is my first build of this size, I'm not to sure on how big of servos this thing is gonna need. Any input would be lovely.

Feel free to leave any comments or questions, and I'll do my best to answer them.

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Senior Member
Thanks for the comments guys, and for the servo recommendation Tritium. As for the plans guys, all I did was take the plans Spencer so kindly whipped up, and doubled all the measurements. Perhaps if spencer doesn't mind, I could change the measurements and add the plans to the thread. The only measurement not on the plans is for the foam spar. All that is, is a standard flitetest spar, just doubled up, so four pieces of foam thick. That runs from 1 inch at the root, down to half inch at the tip.

Plans found here, http://flitetest.com/articles/foam-board-specter-ibcrazy-design

Also, not a lot of progress expected today, the snow storm that was suppose to drop a foot of snow, only gave us a dusting, so off to work for me for the day :(
I'd ask why, but a better question is why not? As for the plans, I have no problem with you modifying them. I used scetchup I believe for the plans. I can send you the original files if you need. Keep us posted, I would love to see video on how it flies.

Also, nice job on the nose of the smaller specter. That looks much better that What I had put together. I think it may be time to revisit that design. Thanks Again!


Senior Member
Good deal spencer, I'll pm you my email, if you wouldn't mind sending me over the files. Here's a few more looks at the nose on the 48" version. All I did was measure 3 inches from the tip and did my best to make symmetrical curved cuts. What I'm really proud of it how I keep the fuselage shut. As you can see I glue in 2 more pieces of foam on the lid, that are a press fit to the inside walls of the fuselage. I norammly cut that hatch in half so the front can be easily opened with the removable wing section is in place. The wing being rubberbanded on holds the rear deck down, then I just use 2 bbq skewers in the front going through the outside wall of the fuselage, into the added 2 sections of foam under the lid. Hope that makes sense, I'll post some pics later tonight when I finish it up to better clarify.



Senior Member
Here's the plans, thanks again Spencer.

100in Specter Wing.jpg
100in Specter Tail.jpg

I did a bit of work on the tail last night, to make it foldable as well. Basically just cut two channels, one in each tail half so I could slide a dowel in for it's removable spar. Also had to split the elevator, which I didn't initially think of. Looks like it will be running off of two servos now, not a big deal.


Here it is folded over.


Going to try and get the fuselage banged out tonight. Then I need to put some more thought into how I want to join the wings/tail section to the fuselage. Also have to figure out what I want to use to latch the topside of the wing and tail section once I have the spar slid into them, I'm thinking velcro, just not sure how I want to secure it to the wing and tail.

More to come later.


Senior Member
Oh and a quick shot of how stiff this wing really is. I'm holding it's whole weight up from the spar hanging out of the tip.

Wing Strngth.jpg

Also a few quick numbers just for fun. This wing has 1600 sq. inches of wing area, and I'm estimating an AUW between 105 to 120 ounces(3-3.5kg). Which according to the calculator will put this thing's wing cube loading between 2.8 and 3.3.
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Senior Member
Got the fuselage done last night, I made a bad cut of the nose section when I was attempting to give it a nice curve. So I was forced to just go with a straight point for the nose.


And a few with the whole plane mocked up.


Foam Addict

Squirrel member
Totally off topic, but that Cat looks just like one of mine. He's always on my workbench, but thankfully has very good manners!


Senior Member
I'm going to run two of these http://www.hobbyking.com/hobbyking/store/__38700__Turnigy_D3542_4_1450KV_Brushless_Outrunner_Motor_US_Warehouse_.html
I have a few props on the way to test the out to see how big I can go on a 3s with them. Most likely gonna run 4 2200 3s in parallel, since I don"t have anything bigger. I have two reason for going with 2 motors, the first I didn't like the rudder on my 48 inch version, it may have scaled up better, but I feel with how close the tail is to the wing a traditional rudder will need a huge surface to have enough authority. So with two motors, hello differential thrust. The second reason is I didn't want to add the weight of a landing gear system. With the two motors swinging an 11inch prop max(I'll more than likely run a 10) I'll have an inch and a half ground clearance with an 11, and two inches with a 10 just from the height of the fuselage and tail section. Plus those motors seem powerful enough to not have a problem pushing this thing around on the ground, or off of it, time will tell. They say they are good for 1420g of thrust each, At most I don't think I'll be breaking 3500g in weight, should be plenty powerful.

As for my kitty there, I wish I could say she has good manners, but she doesn't. Her favorite game is to knock stuff off really high places and watch them fall and make noise. Also she is a big fan of strength testing all of my builds, by climbing all over them when I'm not looking.


Senior Member
Box of goodies came today!!! Expecting to get a good chunk of the plane done tonight after work, stay tuned for updates!



Senior Member
Thanks DDS, I feel like I've been waiting forever for the electronics to arrive. I really wanted to get it ready for maiden this weekend, but in my haste of ordering everything I forgot to get thicker gauge servo extensions. They are expected to arrive monday, so looks like the maiden will be postponed.

Foam Addict, the motors are http://www.hobbyking.com/hobbyking/store/__38700__Turnigy_D3542_4_1450KV_Brushless_Outrunner_Motor_US_Warehouse_.html. Hopefully they will be enough to push this thing off the ground.


Junior Member
I am in the process of building a 60" Specter and was looking for anyone who has built a bigger one. I am wondering if you have maiden you monster yet. I have wings and tail connected, but still finishing the fuse. I put everything on the scale and with FPV I should be around 950 grams. I am going to power with NTM 2830 - 1100kv with 10x5 prop. I'm hoping this will give good results. Won't be a fast plane but it should handle pretty good. Good luck with your build. I am anxious to see you maiden.


Senior Member
Wow seberg, that's super light for a 60" wingspan. My 48" is right in that ballpark, so your's should just float. I haven't quite finished this beast yet, very close though. With any luck I'm going to try and finish it up and hopefully get her in the air tomorrow. Good luck with your 60" as well, I'd like to see some pics/video of it!