Gigantic R/C Jet Turbine Powered SR-71 Blackbird | Hacker News Reader

Gigantic R/C Jet Turbine Powered SR-71 Blackbird

throt-l.com

73 pointselectic37 comments

This is where the real fun is in RC these days: https://www.youtube.com/watch?v=NsxyV-kgfio

Miniquads FTW.

Hot damn, it's Endor.

> Nobody wants to be the pilot of a jet moving at Mach 3.2 when the windshield gives out and leaves you exposed to what must be an instant death

In case there is someone on the internet who has not seen the story:

http://roadrunnersinternationale.com/weaver_sr71_bailout.htm...

Was expecting the usual story about air traffic control, an F16 and ground speeds, or the one with the flyover way too close to the tower, but this one was new to me. Thanks!

Wow that landing was really incredible!

This link starts with the approach (5m:52s in): https://www.youtube.com/watch?feature=player_embedded&v=1lYG...

I wonder what it would feel like scaled up to a regular plane.

That's one fantastic model of my favorite plane.

Have to make one correction though. The article implies an attack aircraft. The SR-71 is a spy plane and never carried any weapons.

Well, there was the YF-12. (Though the model in question is not this two-seat variant which saw testing as an interceptor though was never fielded.)

https://en.wikipedia.org/wiki/Lockheed_YF-12

The model in the video look more like an A-12 (earlier CIA version of the SR-71) to me. They flew with bare metal and black leading edges and were single seat.

The YF-12A looked different, the chines didn't extend all the way to the nose and had a ventral fin

Yup, A-12 as the title of the Youtube video states.

Those engines cost more than us$8k each, I hate to think what all the other equipment on board costs. I'd be surprised if the all-up cost for that model was less than ~$25k

I get nervous enough flying my ~us$800 helicopter.

There's only one engine in there. The red glow you see in the mock engine nozzles is produced by LED light rings; which is a really great idea, btw. That really adds to the authenticity. None the less, the actual thrust comes out of the fixed nozzle you see at the center. I'd pin the cost at significantly less than $25k.

EDIT: I just checked, and the cost of a JetCat (a popular R/C turbine vendor) has dropped significantly since I was in to the hobby. Their largest turbine (>50 lbs of thrust) comes in at around $5,500.

http://www.sitewavesstores5.com/mm5/merchant.mvc?Screen=PROD...

Really? The article claims 2 engines:

> Powered by twin AMT Olympus RC Jet Turbine Engines

Well, the article is full of other issues too. If you look at the grass behind the plane at the beginning of the video you'll see only one streak of the exhaust, so I'm inclined to believe the GP.

I found the original project page. Looks like they did two of these! One version (an all black one) uses twin turbines of a smaller variety. Amazing!

http://www.pulsojet.ch/modelle.php

I thought the LEDs were a nice touch, and I was a little surprised by their placement, assuming they wouldn't last long exposed to the heat of the exhaust.

On review, I thought the middle exhaust was simulating an APU, which didn't seem quite right, but you appear to be correct, there's only one engine in the middle.

I've seen large, turbine powered scale helicopters sell for more than NZ$20k. That said, helicopters are mechanically more complicated, and they don't look like they're supposed to go mach-3, so they have considerably more exterior detail.

Check out the project page. They made a twin too!

http://www.pulsojet.ch/modelle.php

Direct link to video: https://youtu.be/1lYGUROZ_Pg

Heh, just a question - could one use e.g. eight of these jet turbines and create something like a fucking-heavy-load octocopter, or is the reaction time of jet turbines too high for this application?

I mean, a single AMT Nike has 800N/80kg of thrust (-11kg for the turbine weight), so eight of these should provide roughly half a ton of load capacity?

Too sluggish. It would crash.

There's nothing preventing one from using a single turbine for lift (or a cluster of them near the center of mass) and some sort of reaction control system (possibly taking bleed air) for stabilization and attitude control.

I've thought about that for a while, didn't actually went as far as doing a feasibility study or actually building the thing.

No, but not because of the reaction time. Unfortunately jet engines are much less efficient at low speeds like this. They work best when accelerating a large volume of air a little bit, and that means they work poorly in the hover configuration required for an octocopter. Wiki link for the math: http://en.wikipedia.org/wiki/Propulsive_efficiency#Jet_engin...

Larger, slower props are required for maximum efficiency in a hover. The pressure above the prop is never more than one atmosphere, so "suction" is limited unlike when the airplane is flying at a high speed and air is continually forced into the inlet nozzles.

The 800N thrust of those engines is measured at cruising speed, when the only opposing force is drag and the intake and exhaust velocities are very similar. It produces much less thrust starting from zero velocity on the runway, when the opposing force is the inertia of the aircraft.

Jet airplanes, RC electric ducted fans, and jet ski watercraft have similar thrust-vs-velocity response, and are better for their intended purpose as a result - but that doesn't help for octocopters. However, tugboats use a ducted fan for the opposite effect. I am investigating the use of accelerating-configuration ducted fans or "Kort Nozzles" for octocopters.

And yes, the insane reaction time of miniature brushless electric motors is largely what allows these craft to function; you would want variable-pitch props or vectored thrust to make a turbine or internal-combustion craft work well, but that's not the reason they aren't used.

I thought the tail number 06940 looked familiar.

It's the tail number from the M-21 blackbird at The Museum of Flight in Seattle: http://museumofflight.org/aircraft/lockheed-m-21-blackbird (I worked there for several years.) See also http://www.sr-71.org/blackbird/m-21.php

That's a great model. It has proper nosewheel steering, and can throttle back to taxi speed. They taxi it out to the runway and take off properly. When they land, they taxi back to the parking area. That's much closer to normal aircraft operations than most model aircraft.

That video is from 2012. By now, it would probably have an autopilot and camera.

> That video is from 2012. By now, it would probably have an autopilot and camera.

That makes the landing even more impressive :)

My Dad is constantly sending me these sorts of videos. The POV ones where you can get camera footage from the plane itself are really amazing. I guess it is cheaper than owning/flying your own plane :-) But I am always impressed at the time and passion these modelers bring to the fly offs.

Do you have some links to some of these videos? I'm interested :)

tbobborap1's channel on YouTube is a good start: https://www.youtube.com/channel/UCMQ5IpqQ9PoRKKJI2HkUxEw

IMO it's more fun watching mini-quads than fixed-wing FPV videos especially from the very best pilots like Charpu, BorisB, Final Glide, Blackout etc.

The scream on FinalGlides 6S quad [4] gives me chills.

Crashes are always fun too, like when rianrex split his quad in half [6].

[1] https://www.youtube.com/watch?v=3DyRGpKtz-M

[2] https://www.youtube.com/watch?v=wNObwimthF0

[3] https://www.youtube.com/watch?v=F5a9TLb1Yl0

[4] https://www.youtube.com/watch?v=dxU4GdlTHDg

[5] https://www.youtube.com/watch?v=l4DeK7zuLSw

[6] https://www.youtube.com/watch?&v=OKT4cx7UKsk#t=171

[7] https://www.youtube.com/watch?v=Avmc-vQRB4U

Add some small arms to something like that and it would be an urban terror. I assume the sole challenge is the ammo would be too heavy, but clearly looking at the future of warfare...

Presumably you've seen https://www.youtube.com/watch?v=SYz_D89BLUg

The AA12 is an automatic shotgun

Seems to be some debate as to if this is real: https://www.youtube.com/watch?v=SNPJMk2fgJU

There's always so much fear around quadcopters being weaponised. Yet it hasn't happened to RC helis which have been around much longer.

Wow, those things are so much faster than the Phantom 2 we have at the office.

Oh the Phantom 2 can be fast too (not as fast as those I linked to though). The Naza flight controller is very restrictive.

I came in 3rd place at the last MiniQuad race I went to in Oakland. Only because Charpu was not there lol otherwise would have been 4th for sure.

Wow, the pilot sticks the landing. That has to be difficult. The model appears to be moving much faster than a typical R/C plane. If you add the pilot's viewing angle... it must take a lot of practice.

That think looks scarily similar to the Sukhoi T-50 at certain angles.

I'm reading the article and am interested in the topic. However the abnormal scrolling is driving me nuts. Please stop doing that.

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