SR71 BUILD - The Blackbird.

Have you secured the snakes all the way through I think thats the key.I know the worry,I had snakes on my slow flying Red Zephyr,they worked on the ground on thec rudder but not in the air to the right.I fitted a servo at the rear of the fuselage with a short snake and it transformed the model.

The ESC came today so i have no excuse not to finnish it now been thinking about the control snakes, the more i think the more im concerned about them, been looking at the ksm servos only 10mm deep but at 3.5 kg torque i dont think they are powerful enough, shame, but i will come up with something :whistle:

Heres a super SR71 build THE SLED this guys been working on this for years and years, and i thought mine was taking a long time
http://www.mmrca.org/lance/index.html

Did not come out, help needed Mr Moderator

Try this - www.mmrca.org/lance/sledframe.html

I think i will get back to the SR71 build this week i now have the gear to finnish it i think, at least to a flying state so should be ready for the maiden in the next two weeks as long as i have no more hicups.

I was hopeing to get on to the SR this week but i am having to do somthing about my model storage space its only 8'x 6' and im getting to much damage on my models so iv been in there all day sorting it out, quite upsetting to put the remains of crashed planes in the bin bag's, 1 ultimate, 2 revolver's, one eze twin and i have not got to the top shelf yet
Going to build a movable storage rack on wheels

Well i have got it back on the bench to make a start


I found that one of the snakes to the aileron has snaped off where it joins the quick link


So that has decided me to fit the servo's into the wing and get over the problem of not being able to hide them inside the wing
Been fitting the second fan /motor and esc, renewed the silicon wire with 8 gauge and am changing all the connectors




I ran both engines together for the first time but only on 6s 5000 lipo's each everything was ok




So to push on and get it to a flying state

Spent the morning rewiring the run from the lipo's in the fuse to the esc's in the thrust tubes,and makeing the connections to join the lipo's to make 12s.
Then this afternoon i ran the motors at full throttle (had the fire extiquisher ready) on 12s
it was pulling 13.7 kg,
The motors were very warm, the esc's were cold and the lipo's were warm, but very please with
the outcome, fist time i have run both motors in there on 12 s
Made a short video of it but cannot remember how to get it on my computer :silly:

Got to work on the SR today moved the servo's near the controls so now have short pushrods and no flutter








Droped my scalpal on the floor it bounced up and stuck in a vien in my ankle bled all over the place. kitchen roll and masking tape sorted it :dry:

Off flying in the morning, taking the jet, my fun fly thingy, a heli and the SR71 been working on it all day and i believe it is ready to fly :huh: :dry: :S :whistle:
Dont intend to fly it just to have some ground trails with both engines and to see what speed it will reach, i think it is going to need to be fast on the take off run to get it unstuck, who knows it may do a hop.
I balanced it as near as i could but the wind was catching it, i came up with a simple balance rig




Very pleased with the balance of it came out about where i wanted it to,only because i move the servo's to the back, it balanced laterally as well, just got to jiggle the receiver battery to get the balance right




Going to have to rethink the undercarrage secondery doors, they work but i want better so they will be done if it flys

Made a tempory lipo box for itso i can slid the 4 6s 5000 65c lipo'sinto it one after the other through the hatch for the receiver and other gear









Then Natalia thought we should have some pic's before it go's to the feild, dont think she is very confident it is coming back, IN ONE PIECE.

Gave the Blackbird some ground trials today, fired it up on both motors and had three quick runs across the sand then gave it full throttle and then full up elevator and it stuck to the ground like glue !!!! i know i have to mix in the ailerons with the elevator for lift off, but thought it might lift it's nose.
I also have to alter the nose leg make it longer somehow, i think its lower at the nose so the faster it go;s the more downthrust effect it has,
It seemed to have good speed so get the angle of attack sorted it should lift.
It also needs some better wheels on the nose leg, while filming i lost some control and swerved it and the tyres came off
I was on my own but filmed it while trying to control it not a good idea, if i can find a way to load them on the comp ill post them

A couple of stills

Remember BB, you have only airspeed air over the control surfaces so it has to be at flying speed before you have any control! The other thing is, I suspect you're going to have to take those intake cones off!
Another thing, if it ever spins, just put the TX on the ground and watch the party! It will never recover!
Another thing, have you got a bit of reflex on those elevons? It's essentially a flying wing.

Thank you Klipy for all those comforting words