F-15EX Eagle II build journey

[mayan]

Fun story. No pictures, but a lot has happened with this plane since last Thursday.

I was able to maiden it (sort of) on Sunday. It barely fit in the back of my vehicle and I bent some of the tailfeathers getting it into the back. Not a good start. Then, as L Edge wondered, the landing gear was too small and I tore off one of the mains on an ugly takeoff. It was a bit tail-heavy, but flew pretty solidly for a couple of minutes until everything died. No control. Just so everyone knows, this F-15 does glide pretty well unpowered. Unfortunately, it floated right down into some gravel and tore up the nose pretty badly on the side our club shed. Bummer.

So, I took it home and found one of the ESC wires had separated. That explains the loss of signal. However, when I started to rebuild...

...I noticed that the second round of plans was WAY SMALLER than the original. The new plan is only 75% of the previous size, which makes way more sense. Everything fits on standard DTFB. No more butt joints joining foamboard pieces together to make the parts fit. No more shims on the 70mm EDFs to make it fit. My guess is when I printed the original plans, I used the All-in-One plans and printed it on 11X17 paper...somehow it got enlarged. Once I get more of Version 2 cut out and assembled, I'll post some pictures.

Mayan, do your current 3D printed pieces fit your foamboard plans? With these new smaller plans I'm using, I'm printing yours out at 3/4 size to make them fit.

Wow honestly I am not sure. You’re making me wonder what I printed out and cut out and what I designed by. Did the pieces I designed fit perfect on the size you built or where they a bit smaller?

 

[L Edge]

Fun story. No pictures, but a lot has happened with this plane since last Thursday.

I was able to maiden it (sort of) on Sunday. It barely fit in the back of my vehicle and I bent some of the tailfeathers getting it into the back. Not a good start. Then, as L Edge wondered, the landing gear was too small and I tore off one of the mains on an ugly takeoff. It was a bit tail-heavy, but flew pretty solidly for a couple of minutes until everything died. No control. Just so everyone knows, this F-15 does glide pretty well unpowered. Unfortunately, it floated right down into some gravel and tore up the nose pretty badly on the side our club shed. Bummer.

So, I took it home and found one of the ESC wires had separated. That explains the loss of signal. However, when I started to rebuild...

...I noticed that the second round of plans was WAY SMALLER than the original. The new plan is only 75% of the previous size, which makes way more sense. Everything fits on standard DTFB. No more butt joints joining foamboard pieces together to make the parts fit. No more shims on the 70mm EDFs to make it fit. My guess is when I printed the original plans, I used the All-in-One plans and printed it on 11X17 paper...somehow it got enlarged. Once I get more of Version 2 cut out and assembled, I'll post some pictures.

Mayan, do your current 3D printed pieces fit your foamboard plans? With these new smaller plans I'm using, I'm printing yours out at 3/4 size to make them fit.

Two suggestions that I learned was the placement of main gear should be always way back on the wing( and have it sit on a carbon spar that re-enforces the wing) so a bad landing doesn't drive the main gear thru the wing especially with 2 EDF's.

The second is make sure your nosegear is a couple degrees pointed up to the main gear. If it is zero or pointing down, your take off will be much longer or until the nose bounces up to catch positive airflow underneath that lets the nose rise. Had to do that to get my DarkStar to lift earlier.

 

[CrshNBrn]

Wow honestly I am not sure. You’re making me wonder what I printed out and cut out and what I designed by. Did the pieces I designed fit perfect on the size you built or where they a bit smaller?

They fit on the big one. At 75%, they fit the smaller version perfectly. I'm still not 100% sure what happened to enlarge them, but you may want to double-check yours. I know the wingspan of the big one is a little larger than the 43.5 inches called for in the plans.

 

[CrshNBrn]

Two suggestions that I learned was the placement of main gear should be always way back on the wing( and have it sit on a carbon spar that re-enforces the wing) so a bad landing doesn't drive the main gear thru the wing especially with 2 EDF's.

The second is make sure your nosegear is a couple degrees pointed up to the main gear. If it is zero or pointing down, your take off will be much longer or until the nose bounces up to catch positive airflow underneath that lets the nose rise. Had to do that to get my DarkStar to lift earlier.

Thanks for the advice. I plan on using the same gear - hopefully they will work on the smaller second version.

 

[CrshNBrn]

#2 goes together much more easily. Its a more manageable size as well- the landing gear doesn't look comically small, either. I used carbon fiber rods in the tailfeathers- they are rock solid now.

 

[CrshNBrn]

Spray painting today in a cold garage (never a good idea with foamboard!), but its just about all done. I need to clean up the edges of the camo a little bit and put on some decals. I added some small magnets to the hatch. It seems to balance with a 5200 6S battery all the way to the back of the compartment. Whenever the weather cooperates, I'll sneak out and try to fly it.

 

[bisco]

looking good!

13f here this morning

 

[CrshNBrn]

looking good!

13f here this morning

Brrrr... That means no painting OR flying!

 

[CrshNBrn]

A couple more glamour shots now that the decals are on it. Its in the insignia of our local National Guard fighter squadron.

 

[Mr Man]

A couple more glamour shots now that the decals are on it. Its in the insignia of our local National Guard fighter squadron.

Almost looks as good as an off-the-shelf plane, Great Job!

 

[CrshNBrn]

Almost looks as good as an off-the-shelf plane, Great Job!

Thanks! I've never built one of Julius Perdana's planes before, but it wasn't too bad...especially the second time at the right scale. I'd recommend his plans to anyone who misses the old Master Series jets.

 

[CrshNBrn]

Here's a few pictures of the underside and a video of flight #3 today. It flies!!

The photos were taken after the maiden, which was underpowered and sketchy. I busted the front gear and had to hand lunch it. Photos show a lengthened thrust tube and reinforcement of the front gear. It made a big difference. My advice? 1) Don't skimp on the cheater holes and 2) remember, its a jet: keep your speed up on your turns.

I added a rudder and would recommend future builders do the same. On flight #1 it dropped a lot when yanking and banking only.

Also, I added a lot of weight with the landing gear. If you don't want to add all that weight, I think it would also make a pretty good belly lander, if you reinforced the bottom of the fuselage (a big flat surface area) with some packing tape. The big wheel wells give a good handle for hand launching. Of course, when everything works fine its fun to watch taking off the runway, too!

 

[bisco]

success! what a beautiful scale flyer, well done!