LX B-2 Spirit Complete Overhaul/Redesign

[F106DeltaDart]

Around 2 months ago, I picked up an LX twin 64 B-2 Airframe Kit on sale from Banana. I’ve wanted to give this one a shot for a long time now, and the price was right. However, every time I looked at the model, it looked like a cartoon version of a B-2. The outer wing panels were oversized, and the canopy/engines didn’t look right. I finally pulled the overhead view into PowerPoint and overlayed the 3 view of the real thing:


The oversized outer wing panels were definitely the most noticeable, but the canopy also appeared to be significantly oversized for the airframe, and the intakes were too far outboard. Out of curiosity, I stretched the 3 view out until the canopy size and endings spacing was correct:

Now this started to get me thinking.. At this larger size, the outer wing panels are nearly perfectly sized. I printed off the 3 view scaled to the larger wingspan and started planning. A 3” spacer added straight through the center section would stretch it to scale size:

After a few days of debating how to proceed, I got out my jigsaw and cut the airplane in half:

I then fabricated 2 spacers from 1.5” pink foam to fill in the gap.

Next up will be the challenging part: Integrating the landing gear, structure, bomb bay, and battery compartment into the new sections. For propulsion, I picked up 2 of the new 6S 64mm units from the Eflite A-10. Hopefully they will be up to moving this guy once the rebuild is complete.

[Alpha]

That size will fly nicely on twin 64mm, good luck on your project!

[Merry Boozer RC]

F106DeltaDart always wanted to try this model but banana 🍌 has always been a no fly zone for the Boozer. That being said your modifications are looking fantastic and I can’t wait to see the final product. 6 s on this is going to be ballistic definitely might need to add some carbon spares to this bird it’s definitely going to be 100 mph + on that power set up.

[F106DeltaDart]

Thanks Alpha and Wesley! Banana has always been a grey zone for me. I only go there when I need a real engineering challenge :). One of the next objectives on my list was figuring out the Aerodynamic center and setting a CG to aim for. I ran the geometry through an online calculator, and came up with the following static margins:

For now, I’m aiming for around 18% MAC for the maiden flight. This CG position is also going to inform the location of the main landing gear. The landing gear on the real thing is very far aft (around 35% MAC). I will move it to around 27% or so to try to get smoother rotation. Hopefully that will improve things a bit in that regard. It will however, shorten the already close-coupled distance between the mains and nose. I will be planning on installing a gyro for both nose wheel steering and the drag rudders at some point down the line.

The next priority item was the intakes. I cut them back by around a 1/2” to move to the scale position. I’ve always found the giant divots in front of the intakes to be a major eye soar on this model, and wanted a way to make them look more scale. I decided that a cheater grate was the best way to accomplish this. The divot will be covered up with foam, but here’s a preliminary check on how it will look:

Another issue was battery space. Stock, there is no way a 6S battery would ever fit. I was however, able to remove just enough structure to accommodate 2 3S 3700s. Those will be tied in series for primary power. Although I would have loved to have the functional bomb bay, I will probably end up using it as the gyro/receiver bay. There is so little space to put anything in this model, it’s pretty much the only place that works!

[RCjetdude]

Very interesting project Michael. Always have liked the B-2.

[Aros]

Very cool Michael! One of my favorite birds (The B-2 itself, not the LX version, lol)... Great work so far...Really excited to see the final product and flight video. Good luck!

[air-jon]

This is an ambitious hack and very cool! Subbed! It is such a bummer/mystery why they could not get the shape right from the start... I understand there are many variables to designing, producing, shipping models but it's still a bummer. It could have been a really cool airframe from the LX factory....even if the hardware was laughable. I have come so close to buying this bare airframe so many times...

[F106DeltaDart]

Thanks Steve, Todd, and Jon! LX has always been a mystery to me. They remind me of that one student in each high school class that is extremely smart, who just doesn’t put in any effort. They could have a quality product if they wanted, but they seem unwilling to invest the extra effort. And even then, if they had just some minor modifications to a few of their existing planes, they would be smash hits. Their B-25 is incredibly detailed and flies great. It even has more scale landing gear than most composite B-25 models do out of the box! If it had a better spar, more power, better basic hardware, and more durable gear, it would fly off the shelves. Their F-117, and F4F Wildcat are also in a similar vein.

Anyways, I made the blocker plates for the wing divots today out of Flite-Test style dollar tree foam board with the paper removed. I also started filling in all the gaps and panel lines with Hobbico filler. Already starting to look a bit more like a B-2! The canopy is also going to need some mods down the line. Like to original airframe, the oversized cockpit windows make it look like it flew out of a cartoon. Now I’m just waiting for retracts to arrive so that I can start working out the gear configuration.

[Aros]

Definitely beginning to take shape! Very cool, I've never seen anyone attempt this before with the LX version. Can't wait to see it all finished. As for LX, great analogy. Such potential, we've seen it with their ambitious air frames for many years. Hell, their F-117 was my first EDF! (Yeah, let that sink in). Yeah, as you can imagine that lasted about a minute, lol. Good ol' Banana Hobby's descriptors: "Super Stable! Perfect for beginners!!" I didn't know any better at the time but I was their perfect customer: No experience, but HAD to have a stealth fighter! Take my money!



Thank God for Freewing. I don't want to even think where we would be with foam EDF jets without them. Speaking of, if Freewing were to ever develop their own B-2 (imagine?!?!) your finished product might be the closest guess we could ever see as a foamie B-2. I'll be anxiously checking in on your progress!

[scootergenie]

You've peaked my interest, I'll be watching this one.

[T-CAT]

This is a great project, and it is looking spectacular. It is already SO much better than LX designed it.

[F106DeltaDart]

Quick update for today. Sanded down the filler and shot a quick coat of primer over it. Very happy with how the modified intakes are looking so far. Will still need a few rounds of filler, primer, and sanding before it is smooth.

[Aros]

Niiiice....

[F106DeltaDart]

Not much progress today, but I’ve been messing with tape to see what it will take to get the windshield looking a bit more scale. There is definitely an improvement by altering the shape of the windows, but the angle of side braces really bothers me. It gives the side windows quite a different look than the real thing. I’m also not a fan of the thick raised canopy frames. The real frames are perfectly flush to avoid radar returns. For now, I’ll probably just modify the stock one a bit, but if I can get it flying well, I might end up making a new windshield from the start.

Real B-2:

Stock:

Excess Window blocked by tape:

[Elbee]

F106DeltaDart, 90% IPA will dissolve most acrylic paint. I used that to remove all the paint from my F-4 canopy and re-masked the for a more accurate canopy frame and window shapes. Could you do that for this? Best, LB

[tab28682]

Michael, this is going to be a fantastic update on the old LX model. Watching closely.

[Aros]

If it turns out anything like his LX B-25 we will be amply rewarded.

[F106DeltaDart]

F106DeltaDart, 90% IPA will dissolve most acrylic paint. I used that to remove all the paint from my F-4 canopy and re-masked the for a more accurate canopy frame and window shapes. Could you do that for this? Best, LB

Thanks for tip Elbee, I’ll give that a try!

Michael, this is going to be a fantastic update on the old LX model. Watching closely.

Thanks Tom!

Aros, I can only hope it turns out as well as the B-25 did! This one definitely has a few extra layers of complication though!

One of the next things I need to tackle is reinforcement for the center section. With the battery bay, bomb bay, gear bays, and ducting, space to run a spar is near non-existant. What I will most likely end up doing is getting some 1.5-2mm carbon sheets water jet cut to reach around these. Ideally, these frame could also tie into the main gear mounts.

[Aros]

Aros, I can only hope it turns out as well as the B-25 did! This one definitely has a few extra layers of complication though!

Trust I have in you.

[Merry Boozer RC]

This project is absolutely amazing to me. Maybe you should tackle the LX SR-71 in the future or the F117😱 always wanted a flying cheese wedge