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

[GliderGuy]

Hi Evan…Appearance is not always reality. When the AL-37 connector melted, I dissected it and noted the “rolling” of the springy banjo part. I assumed this was a problem which might have been caused by the excessive heat or was a contributing factor to the heat generation. My bad!

Thanks for the education.

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With the AL-37, PJ-50 and B-2 all running 2100 KV motors and the SR-71 using the more powerful 2210 KV motors, I am going to change the SR-71 to the split barrel type ASAP. I’ll sleep better.

_____________

It is also evident that the goal of a 4:30 flight like the B-2 and PJ-50 is unlikely even at 50% power. 4 minutes maybe….with throttle management.

Cruising around at 75% is gonna mean 3:00 to 3:30 flights and require throttle management with a single 6000 mAh battery with 3.8 V remaining as I have measured so far. I have yet to do a full power pass. Doing that = 3 min max.


-GG

[EDF-Jetpilot]

Good point. I will probably do the first couple of flights with the stock gyro then see about switching over. I like to fly with SAFE. Part of the hobby is tinkering.
I'm hoping to hear from others who switch to Spektrum AS3X receivers.

Also,part of the hobby is model detailing. Not much to do with this one. A lot of models come with black control horns and control-rod ends, so why, oh why did Freewing opt for white ones on the Blackbird? Detailing list: paint the control rod heads and servo horns flat black (carefully so as not to interfere with their operation); take a Sharpie (rather than paint) to the screw heads (it is surprising how much difference in ground appearance this makes); probably going to do this up as a NASA plane and get Callie Graphics instead of using the included water decals; maybe trade out the stock pilots for 1/17 scale (smaller) if I can find some.

Yes, I would do that too. I fly everything with Spektrum (AS3X and Safe, sometimes for landings in gale-force winds) and I'm very happy with it. But I'll definitely leave the SR-71 in its original state for the first few flights. But the white control horns... ugh, you said it! I'll paint them with a black felt-tip pen before the maiden flight, I'm just as meticulous as you. I also always paint the inside of the thrust tubes black, most of them are delivered in white, i.e. raw EPO, so ugly. Maybe I'll set up the SR-71 with AS3X and Safe afterwards, we'll see, but first see how well it flies with the original gyro.

[kallend]

. I also always paint the inside of the thrust tubes black, most of them are delivered in white,.

Always? Some nozzles are ceramic coated and are indeed white. Others are natural metal. Very few are black inside.

[EDF-Jetpilot]

Always? Some nozzles are ceramic coated and are indeed white. Others are natural metal. Very few are black inside.

Yes, OK... but the white, like the EPO jets, is just ugly and unnatural. I like black best on any jet and thanks to the exhaust fumes it's somehow logical and natural. The coatings are good, but on the model it looks artificial, I think.

[EDF-Jetpilot]

Always? Some nozzles are ceramic coated and are indeed white. Others are natural metal. Very few are black inside.

this is my awesome back side my planes

[Evan D]

They look good to me.

[kallend]

Yes, OK... but the white, like the EPO jets, is just ugly and unnatural. I like black best on any jet and thanks to the exhaust fumes it's somehow logical and natural. The coatings are good, but on the model it looks artificial, I think.

Photos of real jets show otherwise. The pictures I posted were of real F-104, F-14, F-15, F-16, F/A-18, F-35, Mig-29 and SU-35 none of which are black inside. Actual B-1B nozzles below - not black inside either. Jet exhaust stopped being sooty sometime in the 1960s. Afterburners burn off any soot anyway.

But if if floats your boat to paint them black because you like it and think the authentic coloration is ugly, that's your prerogative. They're your models and you can paint them anyway you like.

(Black wouldn't help with any simulated afterburners.)

[EDF-Jetpilot]

Photos of real jets show otherwise. The pictures I posted were of real F-104, F-14, F-15, F-16, F/A-18, F-35, Mig-29 and SU-35 none of which are black inside. Actual B-1B nozzles below - not black inside either. Jet exhaust stopped being sooty sometime in the 1960s. Afterburners burn off any soot anyway.

But if if floats your boat to paint them black because you like it and think the authentic coloration is ugly, that's your prerogative. They're your models and you can paint them anyway you like.

(Black wouldn't help with any simulated afterburners.)

You're right, I think the EPO thrust tubes are ugly, cheap... they look like toys. Black is good for me, I've never used these afterburners in any jets that partially glow when idling, I don't think they're particularly realistic. But as you say, to each his own, they're not real jets.

[kallend]

I've never used these afterburners in any jets that partially glow when idling, I don't think they're particularly realistic. But as you say, to each his own, they're not real jets.

There's only one brand that glows while idling (and even there the fix is simple). The good ones do not. You should get out more.

https://www.rcgroups.com/forums/showthread.php?4311903-Freewing-Tailflame-afterburner-problem-and-solution

And if you're at all handy, you can make one that behaves exactly how you want it to, since it's fully programmable:

https://www.rcgroups.com/forums/showthread.php?3313547-Make-a-Do-it-Yourself-EDF-afterburner

Since it can drive two tailpipes independently it would be perfect for this SR-71.

[EDF-Jetpilot]

There's only one brand that glows while idling (and even there the fix is simple). The good ones do not. You should get out more.

https://www.rcgroups.com/forums/showthread.php?4311903-Freewing-Tailflame-afterburner-problem-and-solution

And if you're at all handy, you can make one that behaves exactly how you want it to, since it's fully programmable:

https://www.rcgroups.com/forums/showthread.php?3313547-Make-a-Do-it-Yourself-EDF-afterburner

Since it can drive two tailpipes independently it would be perfect for this SR-71.

Okay, thanks. Let's see if I want to try an "afterburner" after all. Since it reduces the jet power rather than increases it, I'm just not a fan of this whole afterburner thing so far.

[Aros]

You're right, I think the EPO thrust tubes are ugly, cheap... they look like toys. Black is good for me, I've never used these afterburners in any jets that partially glow when idling, I don't think they're particularly realistic. But as you say, to each his own, they're not real jets.

I'm a major "scale" guy and I think your black thrust tubes look great. Light absorption could be an issue if you did choose to add afterburners but I think the black thrust tubes look better than the white stock ones personally.

[kallend]

Okay, thanks. Let's see if I want to try an "afterburner" after all. Since it reduces the jet power rather than increases it, I'm just not a fan of this whole afterburner thing so far.

Even that statement is disputable, since some designs (but not all) actually do a good job of fairing in the blunt rear end of the motor.

[kallend]

I'm a major "scale" guy and I think your black thrust tubes look great. Light absorption could be an issue if you did choose to add afterburners but I think the black thrust tubes look better than the white stock ones personally.

Your model, your choice, but don't pretend it's scale.

[Evan D]

Or is it?

_DSC0040.jpg (900×598)

[kallend]

Or is it?

https://www.hobbysquawk.com/forum/rc-airplanes/rc-jets/419430-official-freewing-twin-70mm-sr-71-blackbird-with-gyro-edf-jet-thread?p=420072#post420072

"Always" is not the same as ""sometimes"

"Very few" is not the same as "none".

Incidentally, the last several FW models I have bought did not have unfinished white EPO inside the tailpipe. They were painted grey.

[Evan D]

We can "Always" count on a "discussion".

[kallend]

We can "Always" count on a "discussion".

I'm retired, it's 13 degrees F outside, all my chores are done, all my model winter maintenance is done. I don't watch TV. My "hangar" is full to overflowing. . .

What would you like to discuss?

[Aros]

Your model, your choice, but don't pretend it's scale.

I think I speak for more than myself when I say a less abrasive bedside manner would be warranted and is always appreciated in this forum community.

[kallend]

I think I speak for more than myself when I say a less abrasive bedside manner would be warranted and is always appreciated in this forum community.

OK, in the spirit of helping, here is a picture of the tailpipe of the SR-71 at the SAC museum in Nebraska, that you can use as a reference for color matching. The nozzle was made of Hastelloy X (a nickel alloy), which suffers minor surface discoloration due to the high temperature of the jet exhaust.

[DCORSAIR]

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

You have got to try the chute, it works great.