SR-72 DarkStar, 1:20 Scale, design by FoamyDM

[FoamyDM]

The Goal is to create a 5"proped, 6s powere BDF style RC replica of the SR-72 dubbed son of Blackbird (SR-71). It is also Darkstar, the Mach10 plane from Top Gun - Maverick.
History
Lockheed Martin posted on its website, the Top Gun: Maverick team called them when they were looking for a mean flying machine, and the Skunk Works put together a small team to bring "Darkstar" to life.

The model they built was so accurate that China was reportedly fooled in believing that it was a real experimental aircraft and even reoriented a spy satellite to take photos of it.

The Skunk Works team went from conceptualizing the aircraft to making a realistic model with a working cockpit and keeping it structurally sound throughout the filming.

As always, the job is easier said than done, and the team went through multiple design iterations before the world saw Darkstar on their screens.

BUT WHAT ABOUT ITS CAPABILITIES?

This aircraft can equip the LAAM, SAAM, or SFFS as its special weapons in the game Ace Combat 7.

Without delving into the movie plot, one can say that even though the plane of the screen isn't real, the capabilities it showcases aren't completely fictional either.

Hypersonic planes have been on the priority list of the U.S. military for quite a while now. Lockheed Martin's SR-71 Blackbird was the fastest fighter aircraft ever built. But since the aircraft retired in 1998, the military has been looking for its rightful successor.

The SR-72, also known as 'Son of Blackbird,' has reportedly been in the works and will make its first flight in 2025. Its top speed is expected to be Mach 6, enough to blow off rooftops, and if you look at some of the renderings of the aircraft, you will definitely see similarities with DarkStar.

We also know that the aircraft is meant for intelligence, surveillance, and reconnaissance (ISR) missions but will also have strike capabilities. The only difference is that with increased improvements in automation, the SR-72 is expected to be an unmanned aircraft.

Microsoft Simulator has a Version of the craft:

Specs
Speed: Mach 6+ (Mach10.2 in the movie)
Length 100'

Model Specs
Length = 80"
Wingspan = 40"
Motor = 2207 1700kv
Props = 5x5x3 props
Power = 2x 2200 3S - 6S configuration
Controller = 35A ESC 3-6s BLheli Dshot
Speed = 80+ mph?

Plans
Beta Planset

Build Log Summary:
(Pending)

Glide Test & Maiden:

Builder's Notes:
(Pending)

 

[Michael9865]

Yes!

 

[FlyerInStyle]

View attachment 226446 View attachment 226445 View attachment 226443
The Goal is to create a 5" 6s BDF style RC replica of the DarkStar SR-72 dubbed son of SR-71. It is also the Mach10 plane from Top Gun - Maverick.

Specs
Speed: Mach 6+ (Mach10.2 in the movie)
Length 100'

Model Specs
Length = 80"
Wingspan = 40"
Motor = 2207 1700kv
Props = 5x5x3 props
Power = 2x 2200 3S - 6S configuration
Controller = 35A ESC 3-6s BLheli Dshot
Speed = 80+ mph?

Plans
Beta Planset
View attachment 226444

Build Log Summary:
(Pending)

Glide Test:
(Pending)

Maiden:
(Pending)

Builder's Notes:
(Pending)

Just a note, you put make a 5" - 5 inch 6s bdf. I believe you ment 5', 5 ft. You also put that the length is 100'. I think you ment 100"

 

[L Edge]

Your speed is a good guess, it will be a tough one to fly.

One, make sure your nose wheel is at a positive angle so wind gets under it for takeoff and
2) make sure you add differential thrust to the motors. Rolls are quick(set low rate) and with the long snout, the pitch does not need much change to get the wind under/over to nose backflip/dive your Darkstar. The rudder helps to initiate the turns.

 

[FoamyDM]

Your speed is a good guess, it will be a tough one to fly.

One, make sure your nose wheel is at a positive angle so wind gets under it for takeoff and
2) make sure you add differential thrust to the motors. Rolls are quick(set low rate) and with the long snout, the pitch does not need much change to get the wind under/over to nose backflip/dive your Darkstar. The rudder helps to initiate the turns.

Thank you @L_Edge, Good advice.

 

[Bo123]

Haven't seen the movie yet, but I am excited to see this one fly!

 

[FoamyDM]

Last night I got all the pieces cut out. It's um... big! Bigger than I thought. Technically 84.5" long. And 40" wingspan. I will be ironing edges.

I suppose it's time to get back to work.

 

[FoamyDM]

Started to glue and tape everything down.
And it starting to take shape.

I decided to check the weight.

8 sheets of foam board. Coming in at 529g. Looking good so far.

Tomorrow is the rudder. And I will mount the motor after 3D printing a mount;
https://www.thingiverse.com/thing:3745383

 

[FoamyDM]

This now gets me to the Complex issue of Langing Gear. (complex for me)

This plane NEEDs Retractable landing. The rear gear seem quite straight forward. the go up then down, and are braced.
the front I would prefer it to be steerable and retractable.

Regarding C.G. - a wise builder one said the C.G. is typically 1 wheel diameter in front of the rear wheels of a tricycle gear, and 1 wheel diameter behind a taildragger's main gear. this is a good quick estimate for starting. This gear is at the rudder front.

 

[skymaster]

Started to glue and tape everything down.
And it starting to take shape.
View attachment 226523 View attachment 226524 View attachment 226525 View attachment 226526 View attachment 226527 View attachment 226528 View attachment 226529 View attachment 226530 View attachment 226531
I decided to check the weight.
View attachment 226533 View attachment 226532
8 sheets of foam board. Coming in at 529g. Looking good so far.

Tomorrow is the rudder. And I will mount the motor after 3D printing a mount;
https://www.thingiverse.com/thing:3745383

Iwas going to suggest before you closed it up that you put some formers inside, the intakes maybe you can make them a little bit smaller. but it looks awesome.

 

[Baron VonHelton]

So are you doing the single tail or the double tail??

 

[FoamyDM]

So are you doing the single tail or the double tail??

Single tail from the mov... wait I see my error, two tail is in the movie.
Just added the Vert. Stabs Plan sheet 9 (now in post 1). This can be made 1 or two Vertical Stabilizers

Iwas going to suggest before you closed it up that you put some formers inside, the intakes maybe you can make them a little bit smaller. but it looks awesome.

Do you mean formers in the nacells? I can make them taller, and a 3/8" less wide, Easily. the idea is to house a 5" prop in there. if you want 70mm edf version, I think you could print 1/2 scale.

 

[FoamyDM]

i have updated the "history"

 

[FoamyDM]

Over the last couple days I've. Cut out the vertical stabilizers.

Then iron tapered the leading and trailing edges.

Then I realized I need to get the nacelles right. I couldn't locate my 1 motor so I ordered some replacements.
Initial look looks good.

I spent time printing 5 inch ducts to frame out how big the nacelles need to be to be sure I have the proper clearance for the props.

I thought I had it right. But after I printed the duct shrouds, I discovered that I needed a little bit more height to completely keep everything safe. So I added 3/4-in strips to the top of the Nacelles sides. It fit just perfectly now.

 

[FoamyDM]

Alright, While I should have done this near the beginning, I wanted to check this before the gear is attached, and i run up the motors.
CG CHECK! (from here)
I checked it in two ways.
1. as if the whole body is the wing

2. just the wing surface

Based on the placment of the Landing gear in the movie, and the 3d model I will start glide testing, based on the Wing only CG model.
This Spreadsheet is detailed! allowing for equipment information to be placed to predict were the Battery should be placed. in the list below, the 5Ah, 6S Battery is place in the wing-only configuration.

As I draw the parts, for CG the model has the centroids of certain parts, the FB model weights get assigned separately.

The Left CG model is with the whole body as wing: the Right CG model is using the wing only as a lifting surface:

 

[FoamyDM]

Motors:

ESCs:

Props:
Gemfan 5043 props. (not SUPER agressive) but should be fine for 1.2+kg thrust output/motor.

 

[FlyerInStyle]

Motors:
View attachment 226728 View attachment 226729
ESCs:
View attachment 226730
Props:
Gemfan 5043 props. (not SUPER agressive) but should be fine for 1.2+kg thrust output/motor.
View attachment 226731

how many of them will you have? just one to power such a beast??

 

[FoamyDM]

2 - One per nacelle. This allows for differential thrust and ~3kg (6.5lb of thrust) for a 1.5kg (3.25lb) plane.

I bet I could do a 1/2 scale with 64mm edfs...

 

[FoamyDM]

Half scale... 2.5" (64mm) duct openings...
A little pushing and shoving... yup, 2 sheets and 2 64mm EDFs.

1.5 minutes of sheer joy!

 

[Bo123]

Half scale... 2.5" (64mm) duct openings...
A little pushing and shoving... yup, 2 sheets and 2 64mm EDFs.
View attachment 226737
1.5 minutes of sheer joy!

1.5 minutes as in flight time lol?