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

[Evan D]

Why post that Aros?

Is it in response to a specific question?

Have you flown yours yet?

[Aros]

And I've said it before and I will say it again as it bears repeating: Reduce your aileron throws in this bird. You will be happy you did.

[GliderGuy]

Thanks for the confirmation and explanation. I can’t say “nothing happened”! I aged about 5 years in 2 minutes.

I recall listening to a military jet pilot when he said, “If we lose the Stability Augmentation System, we punch out.” That’s how I felt. First hand…I can say that the SR-71 is a real challenge to fly without a properly initialized gyro.

-GG

[EDF-Jetpilot]

Some of you will be shaking your head in disbelief about the stupidity!!!! Good news = all OK, no crash

Or…It might just be my specific electronics or a behavior that is unique to the SR-71 stock gyro. Who knows?

WARNING!!! I’ve always heard best practice is (1) turn on the xmitter (2) then turn on the RX.

A few times in the past with other planes, I got this backwards and had no issues. Read on…

WARNING!!! Again!!!!!

This morning was calm, so I few the SR-71 4 flights. I noted the xmitter batteries were a bit low after #2 flight. Changed the batteries and ended up getting the RX on “BEFORE” turning the xmitter on.

Everything checked out once I turned the xmitter on, so I took off.

Oh my gosh….The gyro or RX had lost its mind!!!!! It was in a hard left turn condition which took nearly full right aileron to counter.
My heart rate equaled that of Neil Armstrong’s as he landed on the moon!
I barely got it around once and landed. WHEW!!!

I unplugged the RX and then plugged it back in. Took off…all was normal. Made one more flight, too. All good.

LESSON LEARNED!!!!

-GG

PS Total flights now 48
Finding the best landings are with 3 clicks of power until wheels touch.

Yes, exactly, that's how it can happen. It's really important to always turn on the transmitter first, otherwise the gyro won't initialize correctly. Dear RC friends, please remember this very well, because in the "stress" of preparing for takeoff, you always have to pay full attention to this point. Thanks for your input, and it's great that nothing happened!

[stitch]

Those spring type,I have seen them burn it that spring gets hot melts seen it just keep eye on it don't force bunch amps at once 😆 be ok! Myself I only use those kinds up to 4mm ones.spring type lose tension after they keep getting hot over time.

[stitch]

Ya one on left is best all I use,plus sold em for yrs on eBay never had one problem with that kind, another reason overheating is not soldered good. Check wires make sure soldered nice and tight.

[f4u ausie]

I recently Lost my al 37 I suspect that was my reason.. I did same. But turned off tx ..to go back to my car ..left Rx powered..came back. Turned on tx.. did not do another flight check.. vwala. Take off and.. gone. Like last week's pay..

[Aros]

Glad you didn't have to have the dreaded Walk of Shame! I've done my share of stuff that jeopardized a flight but for some reason I've always turned my radio on first before I plug in. A good case study in why that's important!

[GliderGuy]

Some of you will be shaking your head in disbelief about the stupidity!!!! Good news = all OK, no crash

Or…It might just be my specific electronics or a behavior that is unique to the SR-71 stock gyro. Who knows?

WARNING!!! I’ve always heard best practice is (1) turn on the xmitter (2) then turn on the RX.

A few times in the past with other planes, I got this backwards and had no issues. Read on…

WARNING!!! Again!!!!!

This morning was calm, so I few the SR-71 4 flights. I noted the xmitter batteries were a bit low after #2 flight. Changed the batteries and ended up getting the RX on “BEFORE” turning the xmitter on.

Everything checked out once I turned the xmitter on, so I took off.

Oh my gosh….The gyro or RX had lost its mind!!!!! It was in a hard left turn condition which took nearly full right aileron to counter.
My heart rate equaled that of Neil Armstrong’s as he landed on the moon!
I barely got it around once and landed. WHEW!!!

I unplugged the RX and then plugged it back in. Took off…all was normal. Made one more flight, too. All good.

LESSON LEARNED!!!!

-GG

PS Total flights now 48
Finding the best landings are with 3 clicks of power until wheels touch.

[GliderGuy]

You can see some of the small cracked areas in the gravel surface toward the top center of the photo above the B-2.

Correction…14 landings on NEW and beefed-up anti-torsion arms. Not repaired as stated in my prior post.

The strengthening process is:
-Remove the arm BEFORE it breaks
-Remove paint carefully with a Dremel tool
-Wash with isopropyl alcohol
-Fill all cavities with JB weld epoxy
-Thin coat non-hinge areas with JB weld
-Wrap with 0.6 mm steel aircraft safety wire
-Coat all steel wire wrapped area with JB weld
-Reinstall arm to landing gear
-Dremel away any small areas of epoxy which cause any restriction to compressive spring movement.

-GG

[GliderGuy]

Sure…Here is the best photo I have of the gravel size that broke the SR-71’s anti-torsion arms within the first 8 landings. B-2 hasn’t had issues with it other than a broken nose steering arm on one cool 45F day. The area has some very small weathering cracks which probably caused the breakage. Such a cracked area can be seen near the top center of the photo.

-GG

[EDF-Jetpilot]

Calmed down finally!!! Got 10 late afternoon flights. Total is now 44 flights. Sure is FUN!

I’ve been cruising mostly but some rolls and loops and vertical climbs after a high speed pass into a half loop, half roll over the top. Pretty tame stuff, but I’m taking my time.

Approach is slightly nose high with 3-4 clicks of power to about 3 ft…then close the throttle all the way once in ground effect. Easy to hold off and put her on the mains.

My repair/beef-up of the anti-torsion arms has now lasted 14 take-offs and landings on the gravel that originally broke them. There’s more room at this gravel surface place. So, I thought I’d experiment with the beef-up and see how it worked. So far, so good. But my goal is to move to a “smaller” place with smooth asphalt.

-GG

Great, I'd love to see it for you!
Could you post a photo of this "gravel area"? I'd be interested to see how rough it really is. It probably won't be that thick gravel. But it's always better to have no stones at all.
Sorry for my English, tis is not top!

[GliderGuy]

Calmed down finally!!! Got 10 late afternoon flights. Total is now 44 flights. Sure is FUN!

I’ve been cruising mostly but some rolls and loops and vertical climbs after a high speed pass into a half loop, half roll over the top. Pretty tame stuff, but I’m taking my time.

Approach is slightly nose high with 3-4 clicks of power to about 3 ft…then close the throttle all the way once in ground effect. Easy to hold off and put her on the mains.

My repair/beef-up of the anti-torsion arms has now lasted 14 take-offs and landings on the gravel that originally broke them. There’s more room at this gravel surface place. So, I thought I’d experiment with the beef-up and see how it worked. So far, so good. But my goal is to move to a “smaller” place with smooth asphalt.

-GG

[Aros]

Nice!

[NKC-135Fleet]

Definitely had too add the 71 to my reconnaissance fleet…. Not sure what I’ll add next but something else will join the fleet.

[Aros]

Full throttle or no throttle!!

[DCORSAIR]

I was excited to see this bird until, I heard 3 min of flight time. What are you getting for time and what battery, and how do you fly it? Thanks.

Well it depends on what battery you use and what throttle setting you like to fly it at, I can only get 2:30 flying time out of mine, about 3:00 minutes total counting taxiing out and taxiing back, I throttle back to just over 1/2-3/4 after takeoff and do some cruising around with a couple of full throttle high speed passes. I'm using the red/silver HRB 5000mah 100C batts in mine which are almost brand new and they are a little warm when I return and the cells are around 3.77, 3.80.

I love the jet and it flies really well right out of the box and is a joy to fly but it eats batteries which I do believe in my opinion is the worst I've seen from any of my EDF jets. I just can't fly this SR-71 slow so maybe I could do better but that's boring, full throttle passes are the only way to fly an SR-71..............

[GliderGuy]

I was excited to see this bird until, I heard 3 min of flight time. What are you getting for time and what battery, and how do you fly it? Thanks.

Admiral 6S 6000 and getting 3:30 and landing with reserve enough for a go-around and ending with a bit over 3.8V post-flight voltage. Most of my flying is done with a click or two more than 50% throttle stick position and a little 100% hot rodding.

With a total 50% throttle position after take-off, getting a 4 min flight should be possible. It all depends on how much reserve, how low you want to drive the post-flight cell voltage down, your battery condition and capacity, etc.

Pretty much in line with most of my EDF jets.

-GG

PS I try to end with 3.8V so I have a shorter charge time at the field. I get more flights this way.

[Aros]

I haven't maidened mine yet. Sounds like between 3-4 minutes is the average depending on flying style and battery. Actually right in line with most EDFs.

[MeyerVW]

I was excited to see this bird until, I heard 3 min of flight time. What are you getting for time and what battery, and how do you fly it? Thanks.