XF VIPER - Foamboard F-16 EDF

Liemavick

Member
Mentor
WOW, nice build! Great photos, I probably should have taken some (any) during my build.

Thanks Kilroy, as Ive said there were a few adjustments needed to get her looking good.

Joining the front and rear sections once assembled was a bit tricky as mine didn't line up due to earlier errors.

A few things I would pay more attention to, and do first time around on the build now that I'm "smarter" :).

1. When forming the air intake, make sure the top portion is flat. The front section of the fuse will glue to it later. In order for the air divertor and fuse to sit properly this HAS to be flat!
2. When gluing the front section onto the air intake it's imperative you get it aligned as straight as possible.
3. Adding the anhedral (sp?) angle to the stab fins I found a stack of 3 thickness of FB gives you just about 15 degree angle Ben recommends (see pic).
4. When joining the front and rear assemblies the two tabs that protrude forward on the rear section didnt match my angle with the front section. Again, it was an error on my part earlier in the build process. Regardless I made a 50% cut on the tab sections about 3 inches. This allowed me to bend/fold and match the front section angles.
5. The canopy deck, instead of folding it on the score cut the full length, I glued about 3 inches of the score cut in from the flat side, thus keeping it flat. Then formed it into the angle. This allowed it to transition from the fuse angle up front to the flat section at the rear.
6. The canopy itself wasn't as bad as I thought it would be folding and shaping it, but once assembled I couldnt get it to sit flat. I made two attempts at this and both had a curve on the base. I finally trimmed it's bottom edges to get it to sit flatter on the canopy deck.
7. After installing the vertical stab be careful when adding the collar at the base. I knocked mine out of square and didnt notice until after the fact.
8. The servo wires, I decided to have them enter the fuse right in front of the forward fan support. Chances are you will need servo extension wires unless your lucky enough to have servos with really long leads. I then glued the wires to the inside of the fuse to keep them from being sucked into the fan. You can hide the majority of the wire outside by gluing them behind the side stab mounts.
9. After assembling the nose cone, I sliced the overlap paper at each angle. This made lining it up and gluing it much easier (see pic)
10. Hi Ben! Thanks again ;)
 

kilroy07

Legendary member
Did you all see and/or understand what I did with the BBQ skewers on the inlet lip, for landing reinforcement?
Yup, pretty straightforward I thought.

Missing might be a shot where you ended up with battery and electronics and just what to do with the "formers" I almost glued them in as bulkheads until I didn't see any pics to do that. So I used them inside the nose and fuselage to help line the two up (was that the intent?)

The tabs for the Horizontal stab could be a tab longer... Attaching those to the fuselage was a challenging step... (There's a thumbprint immortalized in glue where I got just one of my many 3rd degree burns...) :LOL:

Just how much (and where) you have to trim the vertical collar for the fin would help also (mine is seriously ugly, and another burn...)

The only other "problem" area was the cockpit floor section. Maybe shorten the "crease" lines where it transitions from the nose to the flat. Although, I probably could have test fitted that a couple of more times and figured out how it went together (Honestly, I think a short video of that part would speak volumes on how it was designed to work... (I kept looking at the pics, looking at the part.... Looking at the pics, looking...)
But again, that "might" just be my lack of experience...
 

Liemavick

Member
Mentor
Quick follow-up question - I've been getting questions elsewhere about the inlet lip -

Did you all see and/or understand what I did with the BBQ skewers on the inlet lip, for landing reinforcement?

View attachment 112756 View attachment 112755
Yes Ben, I saw it. I chose not to reinforce it (yet) as it would have made my pictures ugly ;) speaking of reinforcement I noticed you taped the exhaust former to the fuse, did you have an issue? Mine seemed pretty solid after gluing it and I passed on the tape.
 

Mid7night

Jetman
Mentor
Yes Ben, I saw it. I chose not to reinforce it (yet) as it would have made my pictures ugly ;) speaking of reinforcement I noticed you taped the exhaust former to the fuse, did you have an issue? Mine seemed pretty solid after gluing it and I passed on the tape.

In which pic do you see an exhaust former taped to the fuse?
 

Liemavick

Member
Mentor
In which pic do you see an exhaust former taped to the fuse?
1534525738914.png
 

Mid7night

Jetman
Mentor
Oh ok. I think I labeled that something like "rear fuse taper"...it's not really an exhaust "former"... anyway, the reason there is taped wrapped around it is because I cut too deep when scoring the crease-cuts! :p

And the reason it is taped to the fuse piece forward of it was to aid in alignment when I glued it on.

If you do everything clean and proper, like you must have, you don't need all that messy tape. ;)
 

william steendam

New member
yeah. I forgot to do it whilst building, added intake protector skewers after build,,, still worked out fine.. even though the version I built is smaller to accommodate a 50 mm edf I found the parts went together and aligned pretty good,, majority of issues I encountered were my own fault due to lack of attention to detail , for example, I glued in edf , thrust tube and 2 foreward mounts in back to front, started asembly of the fuse and it occurred to me that it probably wouldn't fly as well backwards, after some choice words and some handy knife work I got it rectified...any other issues I found were the usual bevel to make it fit more snug issues that inherently come with all scratch build foamboard builds, this smaller version went together well, I found softing up leading edge of wings with hot glue before folding over helped reduce paper tear , where diverter area glued to fuse was an area of concern when I was test fitting, the edge wasn't a straight line where it met the fuse like in bens pics but I glued up that joining strip thingy anyways , placed it in where it was supposed to go and pressed the fuse down into intake using the table as my friend till it assumed the straight edge and held for 2 mins,,, this bowed the fuse above diverter/intake slightly but end result looked just like bens pic,, one of us should probably make a build video to make it easier for others ,, but building via the pics supplies is quite do able,
 
Last edited:

kilroy07

Legendary member
Meanwhile... In Springfield...

So, the batteries arrived today. I flew the Viper twice (I have a third battery, didn't bring it.)

My observations....
Man, what are the words... Flite Test, if you are listening (and Ben is on board) ADD THIS PLANE TO YOUR LINE UP!
Ben, FANTASTIC job man! While the F-16 isn't my favorite jet... This plane is one of my favorite planes I've flown to date!!
It is big, fast (or slow) and looks simply amazing in the air!!

Seriously, you should be very proud man! So cool that you shared this design with the community.
My build leaves a bit to be desired, but even with my shoddy work she flew like a dream.
I was seriously nervous and didn't expect much, but she just flew (and well!)

This is just a quick video I threw together... Ever since a hard "landing" in my spear, my GoPro has never been the same... this time it was weird feedback in the audio (I wonder if it was because I had the WiFi turned on...) :unsure:

Anyway, It's late, but I wanted to share that if you were on the fence about giving this bird a try... Just Do It!!
 

Mid7night

Jetman
Mentor
Wow, thank you kilroy for those kind words! I'm so happy you had such a great first flight, despite any "builders warts". I feel very similarly to you about the F-16 in general; it's never been my FAVORITE jet, but this model of it is by far one of my favorite to fly - I'm glad it's not just me! :p

Thanks for tackling the build, congrats on the maiden, and thanks for the video!

Ben



Meanwhile... In Springfield...

So, the batteries arrived today. I flew the Viper twice (I have a third battery, didn't bring it.)

My observations....
Man, what are the words... Flite Test, if you are listening (and Ben is on board) ADD THIS PLANE TO YOUR LINE UP!
Ben, FANTASTIC job man! While the F-16 isn't my favorite jet... This plane is one of my favorite planes I've flown to date!!
It is big, fast (or slow) and looks simply amazing in the air!!

Seriously, you should be very proud man! So cool that you shared this design with the community.
My build leaves a bit to be desired, but even with my shoddy work she flew like a dream.
I was seriously nervous and didn't expect much, but she just flew (and well!)

This is just a quick video I threw together... Ever since a hard "landing" in my spear, my GoPro has never been the same... this time it was weird feedback in the audio (I wonder if it was because I had the WiFi turned on...) :unsure:

Anyway, It's late, but I wanted to share that if you were on the fence about giving this bird a try... Just Do It!!
 

Liemavick

Member
Mentor
Meanwhile... In Springfield...

So, the batteries arrived today. I flew the Viper twice (I have a third battery, didn't bring it.)

My observations....
Man, what are the words... Flite Test, if you are listening (and Ben is on board) ADD THIS PLANE TO YOUR LINE UP!
Ben, FANTASTIC job man! While the F-16 isn't my favorite jet... This plane is one of my favorite planes I've flown to date!!
It is big, fast (or slow) and looks simply amazing in the air!!

Seriously, you should be very proud man! So cool that you shared this design with the community.
My build leaves a bit to be desired, but even with my shoddy work she flew like a dream.
I was seriously nervous and didn't expect much, but she just flew (and well!)

This is just a quick video I threw together... Ever since a hard "landing" in my spear, my GoPro has never been the same... this time it was weird feedback in the audio (I wonder if it was because I had the WiFi turned on...) :unsure:

Anyway, It's late, but I wanted to share that if you were on the fence about giving this bird a try... Just Do It!!
Kilroy!! First off congrats on the maiden. BUT there is no way you can fly a 4ft long F-16 EDF in a field that small, no way...;D It's time to change your name to Thumbs of Steel. Great job on the build and on the sticks. It would probably be helpful to all to list what battery, electronics, etc. you flew and your thoughts. Also where did your battery placement end up for proper setup on CG. I'm still in awe you flew Bens design like a park flyer lol Kilroy gots skillz!!
 

kilroy07

Legendary member
It's time to change your name to Thumbs of Steel.
:LOL: Thanks, but that has more to do with Ben's design than my skill... (You haven't see me fly Mustangs...) :cautious:

It would probably be helpful to all to list what battery, electronics, etc. you flew and your thoughts.
First my thoughts; Fantastic scale looking design! Was WAY more docile at slow speeds than I was expecting... (see mustang comment above!)
It's BIG! My workbench is just an old metal desk in the basement (aka "The evil Lab") and she just grew and grew and grew.
IMG_7308[1].JPG

Okay, so hardware;
I fly a FlySky i6X radio and iA6B Receiver.

Generic 70mm duct fan+3000kv Motor
https://www.aliexpress.com/item/1-s...843.html?spm=2114.13010708.0.0.3a994c4dZVtDlU

Hobbywing SkyWalker 60A Brushless ESC (A tad over kill, but I'd rather have a little headroom, I measured around 40a on the 70mm)
https://www.aliexpress.com/item/Ori...406.html?spm=2114.13010708.0.0.3a994c4dZVtDlU

ZIPPY Flightmax 3000mAh 4S1P 20C LiPo Pack w/XT60
These were tapped out at 5 minutes. The C rating is pretty low, but the only other 4S I have are 2200....
So, I went with these. They were warm, but no puffiness so I'll just make sure to take it easy on them.
https://hobbyking.com/en_us/zippy-flightmax-3000mah-4s1p-20c-lipo-pack-w-xt60.html?___store=en_us
(I would suggest a more robust C rating though!)

IMG_7309[1].JPG
I used a couple of popsicle sticks for the battery tray.
(Receiver is hidden under wing.)
IMG_7313[1].JPG

despite any "builders warts"
More like leprosy ... :LOL:
IMG_7310[1].JPG
More Ugliness
IMG_7312[1].JPG
I think the laser spoils me... If I had to spend 20 hours cutting out a set of parts, I would spend a LOT more time on it. As it is if (when) I make a mistake I can always cut another in short order.

That said, now that the design has proven itself I WILL be making a second one and taking more time and what I learned during this build.

Second flight (Absolutely RAW Video... NO edit or polish.)
I goofed when I was soldering up the extension line for the ESC so I didn't have voltage telemetry, just one of those plug in checkers. The last pass I heard it beeping and immediately put her down (as I said, these batteries aren't quite up to the challenge.)
READ: Thanks @Mid7night now my NEXT allowance is spent too! :ROFLMAO:
 

william steendam

New member
:LOL: Thanks, but that has more to do with Ben's design than my skill... (You haven't see me fly Mustangs...) :cautious:


First my thoughts; Fantastic scale looking design! Was WAY more docile at slow speeds than I was expecting... (see mustang comment above!)
It's BIG! My workbench is just an old metal desk in the basement (aka "The evil Lab") and she just grew and grew and grew.
View attachment 112829

Okay, so hardware;
I fly a FlySky i6X radio and iA6B Receiver.

Generic 70mm duct fan+3000kv Motor
https://www.aliexpress.com/item/1-s...843.html?spm=2114.13010708.0.0.3a994c4dZVtDlU

Hobbywing SkyWalker 60A Brushless ESC (A tad over kill, but I'd rather have a little headroom, I measured around 40a on the 70mm)
https://www.aliexpress.com/item/Ori...406.html?spm=2114.13010708.0.0.3a994c4dZVtDlU

ZIPPY Flightmax 3000mAh 4S1P 20C LiPo Pack w/XT60
These were tapped out at 5 minutes. The C rating is pretty low, but the only other 4S I have are 2200....
So, I went with these. They were warm, but no puffiness so I'll just make sure to take it easy on them.
https://hobbyking.com/en_us/zippy-flightmax-3000mah-4s1p-20c-lipo-pack-w-xt60.html?___store=en_us
(I would suggest a more robust C rating though!)

View attachment 112830
I used a couple of popsicle sticks for the battery tray.
(Receiver is hidden under wing.)
View attachment 112831


More like leprosy ... :LOL:
View attachment 112832
More Ugliness
View attachment 112833
I think the laser spoils me... If I had to spend 20 hours cutting out a set of parts, I would spend a LOT more time on it. As it is if (when) I make a mistake I can always cut another in short order.

That said, now that the design has proven itself I WILL be making a second one and taking more time and what I learned during this build.

Second flight (Absolutely RAW Video... NO edit or polish.)
I goofed when I was soldering up the extension line for the ESC so I didn't have voltage telemetry, just one of those plug in checkers. The last pass I heard it beeping and immediately put her down (as I said, these batteries aren't quite up to the challenge.)
READ: Thanks @Mid7night now my NEXT allowance is spent too! :ROFLMAO:
nice, she flies sweet as, , did u have to trim her or was she pretty close already on ur maiden,,, I notice youre battery placement is a lot further foreward than my smaller build version,,, im runnin a 1300 mah 4s but ive had to place it between top of wing and top of fuse part way down length of battery which more or less gets me between established CG range,, perhaps its because mine is smaller , im a couple hours off her maiden but im now second guessin myself , did u set yours up to be a bit nose heavy for maiden ? cheers
 

Liemavick

Member
Mentor
nice, she flies sweet as, , did u have to trim her or was she pretty close already on ur maiden,,, I notice youre battery placement is a lot further foreward than my smaller build version,,, im runnin a 1300 mah 4s but ive had to place it between top of wing and top of fuse part way down length of battery which more or less gets me between established CG range,, perhaps its because mine is smaller , im a couple hours off her maiden but im now second guessin myself , did u set yours up to be a bit nose heavy for maiden ? cheers
William, Ben has his battery right where yours is, tucked on the wing. My setup on the bench the 4s3300 I'm using, the battery is all the way in the nose. I'd trust the CG marks on yours and go for it.
 

kilroy07

Legendary member
but im now second guessin myself , did u set yours up to be a bit nose heavy for maiden
I would echo Liemavick's message; Trust YOUR cg marks...
Since equipment is going to be all over the place (weight wise) I wouldn't be surprised if yours was further back. (Especially since you scaled it.)

Well, it looks like I'll be building another sooner than I thought...

Turns out, a 4' F-16 isn't the best way to shuck corn... I visited a local flying field (my first time there, Thanks Jon!) and turns out wind does weird things coming off of a corn field. Like dipping a wing and rolling you right into it...
It's time to change your name to Thumbs of Steel.
You were saying?... :ROFLMAO:
IMG_7317[1].JPG IMG_7316[1].JPG
That ear of corn was shucked right off of the stalk I hit and the battery was about 4 rows in. :rolleyes:

So... I'm off to harvest electronics out of the bone pile... I'll be back!
39441761_2205747726320541_1285018532374904832_n.jpg
 
Last edited:

kilroy07

Legendary member
Fortunately Jon got some video of her BEFORE the crash;

And here is the Viggen I also flew today, you can see that point (0:30) where the corn tried to eat her too! (Darn corn!) :mad:
 
Last edited:

Liemavick

Member
Mentor
She looked great up there Tim! Sounds like a tough place to fly with those crazy updrafts. Looking forward to version 2.0, I bet she turns out better then your original.
Brian
 

william steendam

New member

finally got to maiden the scaled down f16 on a 4s 1300 mah lipo / 50 mm 11 blade edf 40 a esc ,, my battery placement was a bit to far back , had to put it almost near the same place as Kilroy07 pic above , scaling down possibly affects cg, on the way to rc park wind was gentle, by the time I got there it started getting real windy, decided to fly anyways,, 1st flight tail heavy,, 2nd flight better cg but getting pushed around by the wind, 3rd flight started ok but had a rough landing,, tough lil plane hardly damaged, nose a lil crumpled ,,, I decided to wait for a calmer day for my next flight,, might make it easier for my limited experience to trim her out and open her up
 

william steendam

New member

finally got to maiden the scaled down f16 on a 4s 1300 mah lipo / 50 mm 11 blade edf 40 a esc ,, my battery placement was a bit to far back , had to put it almost near the same place as Kilroy07 pic above , scaling down possibly affects cg, on the way to rc park wind was gentle, by the time I got there it started getting real windy, decided to fly anyways,, 1st flight tail heavy,, 2nd flight better cg but getting pushed around by the wind, 3rd flight started ok but had a rough landing,, tough lil plane hardly damaged, nose a lil crumpled ,,, I decided to wait for a calmer day for my next flight,, might make it easier for my limited experience to trim her out and open her up
apologies for poor vid,, gopro died and 12 y/o son was filming from my mobile phone