FT Style Mini P-38/61 "Black Lightning"

[Aero_Knight]

There is a post for future FT Plan Ideas and there was some discussion on the P-38 and I decided to jump in and do a design from scratch and it ended up being a bit more than what the original goal was. Thoughts, opinions, ideas are welcome while I finalize the design.

Here is the result of a day of modeling:

Mini P-38/61 "Black Lightning"

Turns out the scaling I ended up with makes the design a mix of P-38 Lightning and P-61 Black Widow design characteristics. I will post patterns once I have time to make my software do them correctly.

Some key points:
-Twin Engine with up to 4" Props
-Swap-able Engine Pods (Mini Firewalls)
-Optional Rudder Surfaces
-Two spar wing attachment (Carbon or Wood)
-20" Wingspan
-Bomb Bay Battery Access
-Double Wall Foam Structure
-Prop Flow Surfaces

Variants:

Centerline Prop with 4" or 6" Prop
-Side Pod Inserts
-Swap-able Mini-Firewall


Push Prop with 4" Prop
-Fixed Standard Firewall on rear


Push Pull Prop


Tri Puller


Tri Pusher


Quad Prop (God-Mode)

If you are up to the challenge, here is a rough draft of the patterns with some corrections to the lengths that may work. I don't have time to indicate the bend types but I will get to them at some point this or next week.

NOTES:
-The PDF is ARCH D sized scales at 1:1 but I left dimensions to help manually scale it.
-The "bend" lines are the centers of the bend because the program does not model foam board style bends correctly so I have to manually add the cut locations and such so do not slice the dotted lines unless it is obvious you need to. Go with feel if anything.
-I forgot to make the cutouts to mount the pods to the wing underside. Not the worst since you can make appropriate adjustments to ensure the prop clears the center fuse.
-With the exception of the center fuse most of the pieces should be self-explanatory but feel free to ask for help.

GOOD LUCK!!

 

[JTarmstr]

There is a post for future FT Plan Ideas and there was some discussion on the P-38 and I decided to jump in and do a design from scratch and it ended up being a bit more than what the original goal was. Thoughts, opinions, ideas are welcome while I finalize the design.

Here is the result of a day of modeling:

Mini P-38/61 "Black Lightning"
View attachment 133902

Turns out the scaling I ended up with makes the design a mix of P-38 Lightning and P-61 Black Widow design characteristics. I will post patterns once I have time to make my software do them correctly.

Some key points:
-Twin Engine with up to 4" Props
-Swap-able Engine Pods (Mini Firewalls)
-Optional Rudder Surfaces
-Two spar wing attachment (Carbon or Wood)
-20" Wingspan
-Bomb Bay Battery Access
-Double Wall Foam Structure
-Prop Flow Surfaces

Variants:
View attachment 133903
Centerline Prop with 4" or 6" Prop
-Side Pod Inserts
-Swap-able Mini-Firewall

View attachment 133904
Push Prop with 4" Prop
-Fixed Standard Firewall on rear

View attachment 133905
Push Pull Prop

View attachment 133906
Tri Puller

View attachment 133907
Tri Pusher

View attachment 133910
Quad Prop (God-Mode)

I have 1 F pack motor and a three bladed prop, count me in for a build.

 

[Aero_Knight]

I have 1 F pack motor and a three bladed prop, count me in for a build.

So word of warning. When my CAD software (Solidworks) "flattens" the components, I have to manually add lengths so the patterns aren't 100% accurate, especially with 180 degree bends. I will try my best to trick the program but it may take two or three build attempts to make the pattern valid.

 

[JTarmstr]

So word of warning. When my CAD software (Solidworks) "flattens" the components, I have to manually add lengths so the patterns aren't 100% accurate, especially with 180 degree bends. I will try my best to trick the program but it may take two or three build attempts to make the pattern valid.

alright then, I have been warned.

 

[jpot1]

At that size, weight will be an issue. To get your CG you may want the elevator servo on the boom further forward with a long pushrod. That is what I had to do on mine.

 

[whackflyer]

@jpot1 do you have plans for that bird?

 

[jpot1]

@jpot1 do you have plans for that bird?

Here you go. I re-drew them for DTFB. Original plans are from rcgroups.
https://drive.google.com/file/d/1QPsqg4E8RNyOhKQOkPqtyc47yTrLHgC7/view?usp=drivesdk

 

[Aero_Knight]

At that size, weight will be an issue. To get your CG you may want the elevator servo on the boom further forward with a long pushrod. That is what I had to do on mine.

View attachment 133927

So yours was tail heavy? I think mine will be really nose heavy depending on the battery in the twin engine mode but I may be wrong.

 

[jpot1]

I did mine as a pusher but yes tail heavy. My CG is pretty far forward on the wing and I need a 3s 2200 all the way forward in the nose plus a few extra washers to get it to balance. It flys great though!

Short video of it in action:

 

[whackflyer]

What is the motor and prop size, and wing span? Both of yours look legit!

 

[Aero_Knight]

alright then, I have been warned.

If you are up to the challenge, here is a rough draft of the patterns with some corrections to the lengths that may work. I don't have time to indicate the bend types but I will get to them at some point this or next week.

NOTES:
-PDF is ARCH D size scale but I dimensioned at least one image on each page to help scale it. It’s 1:1 at that scale.
-The "bend" lines are the centers of the bend because the program does not model foam board style bends correctly so I have to manually add the cut locations and such so do not slice the dotted lines unless it is obvious you need to. Go with feel if anything.
-I forgot to make the cutouts to mount the pods to the wing underside. Not the worst since you can make appropriate adjustments to ensure the prop clears the center fuse.
-With the exception of the center fuse most of the pieces should be self-explanatory but feel free to ask for help.

GOOD LUCK!!

 

[FoamyDM]

This is pretty close to The Bloody Widow:

 

[Aero_Knight]

This is pretty close to The Bloody Widow:

Ya the scaling kind of just worked out that way. I love both planes so it was close enough for me. If I did scaling such the engine pods used the standard firewalls then it would probably looks much cleaner and more towards the P-38 lines rather than the P-61 but I wanted to go mini.
I love the turret and black coloring on that model though LoL

 

[FoamyDM]

I love the turret and black coloring on that model though LoL

The bottom has a red hourglass in packing tape. turret was the bottom cup of a styrofoam egg crate I think.

 

[Liam B]

Love love love the Black Widow. As a matter of fact, I built a big one...

https://forum.flitetest.com/index.php?threads/build-log-giant-120-p-61-black-widow.32206/

 

[Aero_Knight]

Almost done with making the patterns more legible. Hope to have new set of patterns done tomorrow and will test them out this weekend. Just got my second F pack and prop set in so I am looking forward to seeing if this puppy will fly should the weather hold out!

 

[Aero_Knight]

Updated Set of Patterns!! Have Fun! I will be trying them out this weekend. Remember to scale properly. Set A is Letter sized paper and Set B is ARCH B so will have to figure out that one. Sorry I couldn't make that page easier to scale.

 

[Aero_Knight]

So I feel stupid. I have been designing using .125” thick board and the boards I have are 3/16” which does make a difference in many cases...I will see how it works out regardless LoL. I’ll have to redo things next week but it may work out...

 

[JTarmstr]

Updated Set of Patterns!! Have Fun! I will be trying them out this weekend. Remember to scale properly. Set A is Letter sized paper and Set B is ARCH B so will have to figure out that one. Sorry I couldn't make that page easier to scale.

Set A seems to be missing a few parts? I dont see the center cockpit or cockpit glass.

 

[Aero_Knight]

Set A seems to be missing a few parts? I dont see the center cockpit or cockpit glass.

They are in set B. You need both. Be warned though I messed up and you will need 1/8” boards not 3/16”. The design needs some tweaking but I am trying to see if it’ll still work.