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

[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]

Nice!

[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

[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]

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

[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]

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.

[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!

[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..

[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.

[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.

[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!

[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

[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.

[Evan D]

Why post that Aros?

Is it in response to a specific question?

Have you flown yours yet?

[GliderGuy]

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.

Hmmm…I didn’t reduce throws on any axis…left them at whatever the default set-ups were.

More important is to increase the EXPO to a somewhat high value. I like 50% on aileron and elevator. I did not add EXPO to rudder, but that wouldn’t hurt.

-GG

[Aros]

Because I’ve flown the LX version hundreds of times, went through a dozen airframes until I cracked the code and found that this airframe is going to be much better off with limited roll. Granted, I haven’t flown this version yet but I can’t believe this model would be all that different. It’s still the same profile generally speaking. The gyro is a big help for sure. Back in the day it was no gyro, just go.

Expo is a biggie as well. Glad to hear the recommended is working. For me personally, my eye test makes me think even less than recommended is not a bad thing. However if recommended works, fantastic!

[Evan D]

Don't take this as an attack but as someone that is a moderator here, works for Motion, etc, making a statement, recommendation, opinion or whatever that is contrary to the manufacturer when you haven't flown the actual plane, to me is something not to do or at least make sure people reading it know it's an opinion based on flying other aircraft.

[Aros]

Don't take this as an attack but as someone that is a moderator here, works for Motion, etc, making a statement, recommendation, opinion or whatever that is contrary to the manufacturer when you haven't flown the actual plane, to me is something not to do or at least make sure people reading it know it's an opinion based on flying other aircraft.

I feel you. I wouldn't say it if I didn't think it was still relative based on the profile and flying characteristics of the model regardless of manufacturer or size. Look at some of the reviews and you will read the same thing. I stand by what I've said. Just because I haven't flown this particular model just yet doesn't mean I am off base here. The SR-71 doesn't want wicked roll rates, period. No matter the size or manufacturer. Clearly this is no high wing trainer we are talking about. Pitch rates whatever, but it wasn't until I reduced the roll rate is when I finally tamed the LX model. Granted, no gyro and I think that will be a major benefit here but I still stand by my stance that this model favors less is more when it comes to aileron authority, especially for intermediate pilots.

[DCORSAIR]

I feel you. I wouldn't say it if I didn't think it was still relative based on the profile and flying characteristics of the model regardless of manufacturer or size. Look at some of the reviews and you will read the same thing. I stand by what I've said. Just because I haven't flown this particular model just yet doesn't mean I am off base here. The SR-71 doesn't want wicked roll rates, period. No matter the size or manufacturer. Clearly this is no high wing trainer we are talking about. Pitch rates whatever, but it wasn't until I reduced the roll rate is when I finally tamed the LX model. Granted, no gyro and I think that will be a major benefit here but I still stand by my stance that this model favors less is more when it comes to aileron authority, especially for intermediate pilots.

Your right Aros, to me there is no reason to set the SR-71 as per the instructions, but then again I always reduce throws on any model and never go by what the instructions say or even by what anyone else says actually. First thing I do when I get a new kit is move the linkages in on the servo horns on all the surfaces, it just tames those maiden flights down for one and also makes for a smooth flight. I always get a kick out of guys with way to much throw and then complain about how bad the plane flies, I have seen over my 41 yrs of flying how people set up the elevator and always have to much then see a stall usually on the turn to final or a snap roll of some kind from to much elevator. The SR-71 likes very little throw on all the surfaces really in my opinion, but hey I'm no expert so ignore my opinion....