Official Freewing Twin 70mm SR-71 Blackbird with Gyro EDF Jet Thread

[Aros]

Again, GREAT report! Love the detailed analysis including the warts and nuances that come with flying such a iconic and challenging bird!

My many years of experience comes from the 64mm LX version and while you can't compare these two models head-to-head obviously, there are flight characteristics that should be similar.

I have said this many times over the years...It took me a long time to tame that bird and it didn't occur until I figured out that the aileron throws truly need to be dampened. Like subtle. Pitch throws can be somewhat aggressive but at the end of the day it comes down to this:

To fly the SR-71 Blackbird scale and successful you need the following:

• Make sure the CG is dead nuts. Don't waver too far from it.
• Reduce the aileron throw more than you normally would.
• Be liberal with your expo. Don't be afraid to explore higher values than normal.
• Treat her like a race car. She wants to "fly around the track". Sure you can do rolls, etc, but this bird is meant for scale flight.

Lower roll rates, decent pitch rates. Don't fly her like some aerobatic mode. Do these things and you will be happy her for quite some time!

[GliderGuy]

SR-71 FLIGHT REPORT….
Disclaimer / User experience may vary. LOL

Fairly sure after more flights and tweaking I will LOVE this plane. Soooo AWESOME looking in the air.

-Range check (150 ft she stopped responding) with xmitter on the ground and in low power xmit test mode. 30 ft is good enough. - check
-Verify the gyro is reacting properly - check
-Light wind - check
-Flight controls - check
-Timer set 3:30 - check
-Taxi a good distance down wind, turn around back toward me and HERE GOES EVERYTHING!!!!

I wanted to avoid yanking her off into a steep, high alpha situation. So…I let her run. She lifted with a typical amount of up elevator. Now she began a right bank and with neutral stick…a slight nose down attitude. Took me about 3 circuits to trim her out.
Once trimmed (not a lot), I concentrated on feeling her out.
She felt best at 3/4 throttle like the F-4. 1/2 throttle seemed a bit sluggish. I need to LEARN about this because 3/4 throttle = short flight.
Again, the overhead passes look AWESOME!
Elevator sensitivity is about right. But after 3 “unsteady” approaches, I’m gonna add EXPO to the elevator, too. Can you say, “PITCHY APPROACHES?” LOL
It was easy to keep her from not getting too far away, but I am used to hot rodding around the sky with the ever so fast PJ-50.
At one point, I made a too steep turn, and she reversed direction in about 80 yards diameter circle. That caught me off guard. She will turn TIGHT!
Cruising around, you will notice how sensitive to roll inputs she is. EXPO needed.
No problem staying oriented. Of course, at a distance from the side, a 45 degree bank either left or right is gonna look the same. THINK about your control inputs. What did you just tell her to do? Then if correcting a bank gets worse, do the opposite!
Lowering the wheels ADDS A LOT OF DRAG! Every time I extended the gear, I ended up at 3/4 throttle to “feel” right. THERE WAS NO PITCH CHANGE when raising or lowering the gear.
On base leg, reduced power to 1/2 throttle. Then 4 more clicks less power on final. Now you’ve got to concentrate. Without EXPO on the elevator, she’ll get pitchy on you. Working on attitude and ground impact avoidance, she landed a bit hard. NO ATTEMPT TO START A CROW HOP! She landed and stuck!
The second take-off showed more left aileron trim was needed. Then I had some REAL fun cruising about. Low passes will be fantastic.
The second landing was a terrible approach. A gust hopped her up outa ground effect and into a nose high and moving sideways over the ground and TOO SLOW situation. Adding a bit of power prevented a hard drop in. What was good….She stayed in control and did not stall or drop a wing. Touchdown was jet nozzle bottom first, but she stuck and stayed straight. No crow hop.
The 3rd take off was typical EDFish. Stayed straight and nice climb out. PLENTY of power!!! I also ended up with about 2 mm of left rudder trim. More fun cruising about and learning her control characteristics.
Focusing VERY hard on the 3rd approach pitch control, I passed by way too high (head high) much above a normal approach for me. But I had plenty of pavement ahead, so I worked on the landing without rushing. FINALLY, a good landing!!!
Will she be hard to land…NOPE! Once the right speed/attitude/throttle settings are learned along with some EXPO, landings will be nice.

6 ch = no chute, no reverse, no mode change for the gyro. A ham radio friend said pull these unused leads from the control box to be safe.

Have fun! Report your flights. Share your tips.
What a unique experience the SR-71 will be.

Any buyer’s regrets? Absolutely None!

-GG
RC Experience level: MRC - P-38, F-4, AL-37, B-2, MIG-29, PJ-50, A-10, and a touch of SR-71

[Aros]

Fantastic maiden report as usual GliderGuy!

Appreciate your detailed reports and analysis. I’m hearing reports that the throws need to be tamed. YES! You don’t want to fly this bird with high rates for any reason. Stick to low rates and minimal aileron throw. Pitch throw is fine but keep the roll throw minimal and she will be happy. In fact, if there’s enough people that complain about how over sensitive the recommendations are from the manual I can update it accordingly so please let me know if you have thoughts on that.

Got mine put together tonight. She is GORGEOUS!

[GliderGuy]

SUCCESS!!! 3 flights in freezing temps, but very light wind (about 5 mph).

Let me first state that I reserve the right to change up all the below as I get more experience. BUT, my first impressions are what you will also/probably experience.

Use this info to help prepare yourself mentally. And remember, as the throttle comes up on your maiden, to say, “Here goes EVERYTHING!”

SUGGEST you add clip-on RF chokes on the wires coming from each ESC as close to the ESC as possible. Put a choke on the wires going in to the fuselage. I also added a clip on choke by the green ferrite choke between the BEC and receiver. Much discussion is found in other forums about the benefits of RF chokes.

Be patient as I offer a few tips and observations before the flights are discussed.
- She makes wide turns on the ground. However, this means she isn’t twitchy on take-off or roll out. For tighter ground turns, switch to high rate (remember to go back to low rate).
- There was no tendency to crow hop. My 3 landings were OK, but not nearly smooth. Once on the ground, she sticks.
- With an Admiral 6000, pushing it all the way to the rear of the front compartment = Good CG for your maiden. She balances a “tiny” bit nose down with the gear down using my finger tips at the CG mark.
- When you decide to make your first flights, go someplace with a LONG runway. I WOULD NOT attempt your first flights on a short runway. You’ll need space to ease her out of ground effect and flair. She will probably try to float up on you, so having room to ease her down and not rush things is helpful.
- Put a dab of RTV silicon rubber on the bottom-rear of each jet nozzle. I managed a landing or two nozzle first. Makes a heck of a noise, but only minor scratches resulted. Also, put a dab of silicon rubber on the farthest rearward outer wing tip on the bottom. This is where the wing tip impacts the ground in a too nose high and not level landing. Saves getting scratched paint out there.
-Set some aileron EXPO. She rapidly responds to aileron inputs. You will want to tame this a bit. I made all 3 flights on low rate and no EXPO. Gonna adjust that before the next flights.
-She tracked “almost” straight during taxi. Thanks FW/MRC for paying attention to the small details.
-Add some clear coat over the decals. The edges began to lift after only 3 flights.
-Set the timer for 3:30 with a 6000 mAh battery. You will want to start your pattern at 3:00. All 3 flights ended with 3.8 V measured.
-Line up the inner control 3 mm ABOVE the horizontal line on the tail cone….at the rear edge. Then line up the outer control trailing edge with the inner control trailing edge.
-Gyro input open…defaults to GREEN (normal) mode. I only have a 6ch rig.

That’s long enough….next post is all about FLYING AN SR-71!!!!!!! Gotta go eat dinner…stand by!

-GG

[Husafreak]

C'mon someone fly it and report back, LOL. A flying buddy has his ready to maiden and I may be involved in that this Saturday. I've watched the MRC videos and it looks like it can handle a pretty high AOA and doesn't flare much, just a cosistent descent to touchdown at approach speed. Kind of like my FW F-104 90mm lands. I'm curious, does it have flaps?

[Aros]

Got mine late tonight. Too tired to build her completely but what a presence. What a size. What attention to detail. Freewing nailed it. Can’t wait to build her completely soon.

[Aros]

Some history on the M21 including a tragic end…

The Lockheed D-21 unmanned drone was launched at Mach 3 from a pylon mounting on top of the rear fuselage of an A12 Blackbird. The designation of the A12 then became an M21 with the D-21 installed. Two A12's were modified (#60-6940 and #60-6941) to carry the D-21 Drone. In June of 1963 a D-21 was mated to a mother ship for the first time. Actual first flight did not occur until December of 1964. After flying the Photo Reconnaissance mission, the D-21 flew to friendly territory and the camera was ejected from the D-21 Drone. The cameras were recovered in flight by a C-130 mid-air recovery system. The D-21 drone would self-destruct at a low altitude. Kelly Johnson, Lockheed Skunk Works Chief Engineer, cancelled the M21 program when a D-21 was launched into the area behind the cockpit of the M21 resulting in loss of the Launch Control Officer's life and loss of the aircraft. The D-21's then was mated to a B-52H Stratofortress (Project was called Senior Bowl). Five operational missions were flown in this configuration over China. Operations ceased due to political reasons, cost and difficulty of operation. The "Museum of Flight" in Seattle, Washington has the only A-12/Drone display combo in existence.

[Aros]

A buddy of mine is going to paint his in the M21 scheme. Great scheme and a nice way to help with any concerns of gatoring as well. I painted one of my LX versions years ago. Added bonus points for anyone who would add a 3D printed D-21 drone!

[Pete914]

So stoked on this jet. Will be buying when I save up some cash. What a beauty. Nice work MotionRC and Freewing. Keep them coming!

[CAPTNG]

For those of us who need readers for regular print, here's a PDF of 8x10 phone-photos (i.e., not great resolution, but readable) of the Freewing Guard Manual. Some translation need for Chinglish. Freewing Guard Manual.pdf

[GliderGuy]

LOL - My Torx driver fit. That’s what prompted my comment. I made one other mistake in my life. It was when I thought I was wrong, but it turned out that I wasn’t.


-GG

[CAPTNG]

GG- "A majority of the screws are Torx".

Are you sure they aren't allen?

They are 2mm hex

[Evan D]

GG- "A majority of the screws are Torx".

Are you sure they aren't allen?

[Aros]

All done except for the decals.

Post build impressions…drum roll please…and I am not affiliated with MRC LOL…here goes…

The quality of this PNP plane is excellent. I did not run into any snags getting her ready. The Admiral 6000 needed to be slid to the aft of the front battery bay to get the CG spot on (gear down). If one were to go with 2 batteries, some tail weight would be needed.

The range check was great. All quadrants. I have yet to taxi her, so I cannot comment on how well the nose gear is centered straight.

I added RF Chokes right at both ESCs on the lines that head back into the fuselage and an additional RF Choke between the UBEC and the RX. There is a green toroid ferrite choke already installed. I added another. RF Chokes are SOOO important to help prevent RF noise from the ESCs from disrupting your receiver.

A majority of the screws are Torx. I liked that! The inner main doors came default to “not scale”. They close after gear extension. I liked that that, too. It gets them out of harms way.

All the factory-installed screws were tight! The gyro was default “normal” (steady green light), and test “flying” in my hands proved that the gyro configuration is correct. There is an App you can download to configure the gyro, should you need to.

With the magnetic nose off, there is ample room in the bed of my Titan. Her right main fit into the tie down for the B-2…nice.

There is a seam line in the tail cone. I lined up the inner control surface with this seam. Then I lined the outer control’s trailing edge to the inner control’s trailing edge. I’m gonna start with about 3-5 mm of “trailing edge up”. Most of my birds require up elevator in cruise.

Rain for the next several days. Ugh.

Overall, I am VERY well pleased with the quality and design features. I’m ready to see how she holds up to her first 1,000 landings.

Next up…pilot flight reports as soon as the weather permits. Not going with any EXPO and will maiden on low rate. 6 ch gear, so no chute, no gyro settings changes, and no reverse thrust. I do plan to upgrade radios, so these other “neat’ features will be enabled soon. Timer is set for 3 minutes, and I will maiden at 50% throttle cruise. I anticipate 4-5 minutes at 50% throttle plus some full power acro (loops) and fast low passes…leaving 3.8V is my goal.

-GG

Nice! I look forward to your full maiden report!

[Evan D]

I always say plug in a surface (aileron, elevator or rudder) surface as airflow could move the surface and crash your plane. I don't think the chute would have this problem and since the gyro defaults to basic gyro I think that's okay as long as you are 100% sure it's doing things right. Not sure about the reverse, it may have to be plugged in for the ESC to arm. I think I have heard some had that problem. Easy to test.

[GliderGuy]

Comments anyone?
Unterminated inputs on the gyro and control board….

Until I purchase a new TX/RX, I’m not using the parachute, reverser, or Gyro Mode leads. Is it ok to leave the unused wire leads connected only at one end (open/unconnected at the other end), or should I pull them out of the plane?

My concerns are…these “might” pick up stray signals and conduct them into the inputs if left in the plane and only connected at one end.

EE folks out there…Thoughts? Am I being overly cautious? Best practices? Thanks.

-GG

[kallend]

May I ask why you want to do that? Don't cause yourself any more problems and use the built-in gyro, that will definitely work better.

How do you know this? My experience with Freewing gyros, both built-in and stand alone, has been uniformly negative. I won't use them any more.

[Evan D]

If you don't plug in the gyro mode it does default to basic gyro (same as your B2). If you plug in the mode you can have auto level (SAFE) and off (again same as your B2).

[GliderGuy]

Can’t edit my prior post….#*!?**$&@

Hi Evan,
According to the documents, GREEN logo light is the basic flight mode (default). A BLUE logo light on the gyro = auto level mode.

Mine came defaulted to GREEN logo.

-GG

[GliderGuy]

It does seem weird, but it works. The B-2 is the same.
Each of the single wires is a SIGNAL wire. So rotate/install every single wire connector onto the SIGNAL pin of your RX. In other words, all single wires will line up.

The color of the wire can be ignored.


-GG