SR-71 90mm edf

[chaos23]

this will be a thread on my journey to design and build a balsa SR-71.

another thing i will be doing is providing the plans on here for FREE yes free. as i don't think its right to build a balsa from the plans of 30 years ago that are A. too heavy and B. intended for turbine jets.


information/reference
sr-71 resource
the original of mine

 

[xuzme720]

Oh wow! The -71 is one of my absolute favorite planes! I'll be watching this intently!

 

[jhitesma]

Same here - probably my all time favorite plane. One of the best most detailed non-flying plastic models I built and one of the most successful model rockets I built as a kid as well

Last month we had to make a trip to LA for my daughter to see an eye specialist (which thankfully turned out to be concern over nothing due to a misdiagnosis by our local doctor erring on the side of caution.) After the doctor visit we wanted to do something special for her and I suggested the California Science Center because she loves rockets and they've got Endeavor on display and I figured she'd get a kick out of it. (She's only 3 1/2 but she did get a kick out of it - but was disappointed that there was no fire coming out of the engines and that she was too short to try the simulator.)

What I didn't realize was that they have the titanium goose (2 seat A-12 trainer - predecessor to the SR-71) mounted right next to the parking lot. As excited as we were to get inside and see the shuttle I pushed both my daughter and my wife's patience almost to the breaking point before we were even out of the parking lot with my foot dragging trying to get as many looks at it as I could

I've lost many a light night reading various sources of information about their development and history. Absolutely love blackbirds...

Even if I don't trust myself to fly a balsa one I just may have to tackle building one when you share your plans and just keep it safe until I do feel ready to try flying it

 

[chaos23]

ok, so as to not go into this massive undertaking with no previous balsa knowledge, i picked up a ME-109g kit from my local store, 6 hours later and its done ill post pics and a blurb with the things i learned in the process.

but for now its time for the BB SR-71 update, basic 3d shell is modeled and im moving onto the guts of the actual balsa structure


this shows the separate parts ill construct for transport, then pop it to gether at the field

front

perspective

side

top

as you can see i have only modeled half to save time and to ensure the plans are exactly mirrored at the end step. also i have not modeled the elevons and elevators or the end of the motor nacell as that will be for a thrust vectoring unit.. my target flying weight is under 8kg as the two mercury alloy edf units produce 8.5kg max. next up is the landing gear, ill go away and research what gear i need and ill model and design for them.

 

[Tritium]

Oh wow! The -71 is one of my absolute favorite planes! I'll be watching this intently!

SR-72 is being built. High Altitude Tactical Craft!

Thurmond

 

[xuzme720]

SR-72 is being built. High Altitude Tactical Craft!

Thurmond

I hadn't heard about that. I'll have to look into that!

 

[chaos23]

http://www.sr-71.org/photogallery/blackbird/17976/

i have chosen the 976 to be the model designation for the scale accuracy

 

[xuzme720]

You should do the only "C" model they flew. It was nicknamed "The Bastard" because it was a hybrid of a couple of parts, mainly the front portion of a functional static testbed built for engineering and the rear from the first YF-12. It also had issues where it always seemed to yaw and had frequent maintenance gripes. It only flew about 500 hours before being removed from flight status in '76. It just has a more unique history than most of the -71's.

http://www.sr-71.org/photogallery/blackbird/17981/

 

[chaos23]

yeah i read through them all, and i did like the C model but as i have and evil master mind friend we call the bastard, along with my luck it would likely be plagued by the same control issues. the 976 also has a very rich history not told on that site as it was the first of the sr-71 it flew alongside the yf-12's, a-12 and M-21. also it was an air force plane where the yf, a and m were CIA planes. im currently reading Richard H Graham's book on the history of the sr-71 and its sisters and even it daughter the D-21 drone which i have planned to build as well, a hard task as there is not much room for internal parts like the battery.

 

[xuzme720]

Feel free to post more of that history on 976 when you get time. I was unaware of it's role with the other ships. Of course, it's hard to get some of that information, even now. It is getting much easier than it used to be for sure though!

 

[chaos23]

update time... so after slowly but surely creating my 3d mockup in maya and researching costs, build methods, scale structural forms and so on.. balsa is just gona slow me down and cost allot for this size and scale. but i will not be stopped, so after more digging and thinking i found my answer...
3D PRINTING

yes im going to buy a 3d printer to create a more intricate and tougher sub structure, along with CF i dont think i will have any balsa in the end... but i will continue to keep this thread going as i bring my SR-71 to life

 

[chaos23]

i found the printer for the job.

 

[Cyberdactyl]

I suspect this CF printer is in the very early stage of development since most of the video shows the same small and flat piece being made. Most of the video images show very little about the technology, i.e., views of the machine making something flat and small, guy drawing a French Horn, someone flying an RC heli, guys holding a small piece of plastic, etc. overlaid with audio of how revolutionary it all is.

 

[chaos23]

I suspect this CF printer is in the very early stage of development since most of the video shows the same small and flat piece being made. Most of the video images show very little about the technology, i.e., views of the machine making something flat and small, guy drawing a French Horn, someone flying an RC heli, guys holding a small piece of plastic, etc. overlaid with audio of how revolutionary it all is.

ummm.. did you go to their website? what you see is a dev kit you can purchas now. the part being printed is a demonstration of a part the was made for a race car. other parts have been made and the printed CF parts have been tested to be stronger then 6061-t6 aluminum. the final production release can be pre ordered for $4999 and is expected to be released end of 2014. and in the video he also mentions its been in the making for 8 YEARS!!!! not exactly early stages
https://markforged.com/

 

[xuzme720]

I see what you mean, but "in the making for 8 years" only means that he has been trying to make it work for 8 years. I'd agree with Cyber that this is still in an early production stage since the full production model has an end of this year due date. I'm guessing that is what Cyber was getting at. In no way does that mean this isn't working now or that it won't work at all. It's a very cool next step for 3D manufacturing for sure and I'll be watching closely!

 

[chaos23]

what seems to have taken so long is the knowledge for this type of printer has only really become wide spread in the last 4 years, the other issue they had was with the new CF infused resin type plastic (which was invented for this printer and has a nasty price of $550 a pound), and the fact that the people on the team include the former CEO and founder of SOLIDWORKS!!! not sure if you know who and what that is but its nothing trivial, and the product they have now is more sound then other dev kits like say the oculus rift. and for a $1000 more then the very shiny polished MakerBot
Replicator, you get 2x the build volume, 2x the printing heads and all the other functions plus wyfi connectivity minus the smancy screen and the high end stereo nob

 

[chaos23]

I have moved to the fixed wing electric aircraft section SR-71-90mm-edf