EDF dual stage after burner concept. Will it work?

[mesolost]

So I have this crazy idea. Take a peek and let me know if I've put enough thought into this. ^_^ I think it should work and may do more than just look really awesome. And even if it just looks kewl ^_^ I think this'll be a rig to show off.

I use another guys EDF flame jet idea as a jumping off point for a basic proof of concept to the fundamentals. If I don't get any extra thrust then hopefully it just looks insanely awesome as it flies. =D Link to his jet is below.

For fuel I'll start with a larger butane can but I'm gonna get a refill adapter for a large propane tank (grill tank) and do it up like filling a lighter. I've done it before so don't worry there. ^_^

The controller for the engines will be separate from the flight controller. I'll probably use an OrangeRX stand alone stabilizer so I can use an 8+ channel setup. Extra channels would be for later control of fine tuning the left to right thrust vectoring so we can have it focus on the CG line.

If anyone knows where to get a S.A.F.E. receiver or flight controller PLEASE let me know. =p I could have my engine control monitor the system and if it completely looses radio link it could sequence SAFE Panic, to flight mode beginner loop tight circle, ever so gently down and reduce throttle and land. Ya it'll roll a bit but it'd be a safer than not landing with a compressed gas tank on it =p

Video: http://youtu.be/9i12dlBiwjI
Original EDF Jet idea: http://flitetest.com/articles/edf-afterburner-2
Stelarisware with touch screen demo: https://www.youtube.com/watch?v=gs-sNRMekKg

 

[mesolost]

I want to get an 8 channel system at least for this. 3 regular channels and 1 extra switch to the 3 axis stabilizer out to 4 servos. Throttle to the FC (stelaris ware board) then a channel for start and run engine mode selection. That's the default 6 there. Now I want an analog channel for thrust L/R trim on 7 and lights on 8. The gear would be triggered with the engine flight mode switch. Brakes will be triggered by throttle below 25% or so in engine start mode and begin pre-locked via an unlock button on the touchscreen.

As for the fuel I'll be using a large butane canister with a twist. I've done back filling with them, removing the fuel from lighters. I'll be getting a refill adapter for a grill propane tank to small bottle adapter and using that method to recharge the cans. ^_^ I've already found metal body 12v solenoid valves.

Like what I think I covered a bit in the video there I wont be using the heated pre expander like he uses. I wanna bench test the setup and know what temp I can run the motors at safely, then take that hot but not too hot temp and use that feedback to overpower the motors some so they heat up a bit more. Then with the expansion idea I have, when I kick on the engines the FC will be able to temp control the system while the gas is comin out. Since the spray is right there we'll just split it in 2 and use it to not only heat and gasify the propane faster but also cool the motor. With this in mind as the engine temp begins to drop we can then increase the power into the motor a bit because we have a greater heat envelope now. As the system runs the FC will vary the true max throttle as determined by highest temp motor.

The ESC's I'll get will be overkill so I know they'll handle WOT 100% of the time. I'll probably mount them so the heatsinks are just over the entrance to the motors duct for serious cooling. Of course I'll have it log engine data so I can quick browse it for anomalies and maintain the system. Since the lighting would be an OLED setup driven by the FC I can use the lighting channel as an analog pattern selector. If I have enough pins left I can add on individual battery cell monitoring and logging in addition to the already planned LiPo monitor. OLED system will have different blink codes for battery low, gas out, and engine failure.

Just a bit more info and plans for later reference and to help refine the design. ^_^

 

[mesolost]

Ok so the jet mechanic has helped me refine the design even more. We're going with a ridged aft can for cooling reasons. We've also switched the one ring per engine with a combined after burner into a complete single engine with 2 primary rings and 2 additional afterburner rings. The overall intent being to have better control over the heat control. Most home made engines you see don't account for the air rotation and often times you see the aft end glow like crazy. We don't want that here so we'll use the dead space between the initial flame holder and the EDF blade for some fins to counter the rotation. Now that we have straight air we can more accurately control the fuel spray and determine how and where the flame will flow.

With the new configuration for heat control and efficiency we can change up the control system to run off an ATTiny85 per engine. This is intended to be a cheap and efficient way to properly control this method of engine setup with all the fail-safe's to prevent a disaster. If we get this built to a level of safety that both an Air Force jet mechanic and a NAVY Submariner Nav Electronics Tech approve on we'll look into doing a kick starter on it. ^_^

The overall intent of this endeavor is to end up with a nice lookin plane, taxi it out to the runway, and just drop the hammer and watch the jaws follow. =D

 

[mesolost]

Here's some notes.

 

[mesolost]

Ok, here's the newest ideas on paper. Ideas not there, if I go the way of the touchscreen, normal display will show basically 3 rows (right side up to screen viewed from side of plane) 2 @40% screen height for each engine with ESC Throttle in displayed in % of throttle with 100% being actual max input specs for the motor. Engine RPM as sensed at the ESC output. (used to tune throttle % input further to RPM match left and right sides) Amp meters on each ESC will monitor power input for throttle translation calibration. This is because since we're running 2 EDF's and we want enough electric time to enjoy all our gas ^_^ plus the additional overhead in power we have to really make those EDF's kick. Each engine is finished off with a few safety temps. Between the engines is the master gas armed, primary on, AB on indicators.

The entire screen is finished off on the bottom with 3 buttons, Master brake lock, warm up, and "Hammer Time" Master brake lock is obvious. On power on the EFC will brake lock the system until you touch the model to release it. The warm up option will hold brakes locked and run up the EDF motors to preheat the primary gas system and flash the lights and throttle down when complete. The "Hammer Time" is my special ground demo/system diag/test mode. Press the button and the entire screen becomes a giant red button with one med-small green confirm button in the center. Once engaged it will sequence touch screen only input except brake signal from receiver. System will heat up the EDF's but will not allow any higher throttle than maintain med-hot regardless of engine cooling except if the engine overheats of course. Once the coils are warmed up the lights will flash 50/50 for 2 seconds and the engines will fire up the primary as the lights go steady. After about 2 seconds the system will check if the brake signal is ON or OFF and will only check at this moment after test has been engaged. If the gear switch is on the primary will continue to fire for 2 more seconds and the system will shut down and return to mode 1 taxi take off landing. If the gear switch is off then the after burner will engage for 1 second on, 1 off, 1 on, then 2 more seconds of primary only followed by a shutdown and safety lockdown with auto cool protocol. System will not disengage safety lock until the brake is switch back on.

Although we will be heating the monkey snot out of these electric motors by running 4 cell motors on a 6 cell battery, we have the master engine computer. This with a certain power on switch setting will enter an engine setup and parameter input screen. Here you'll set the motors cell rating(4 or 5), max voltage/time specs, motor's KV (both motors MUST be exact matches), Max amp draw allowed limits/time, nominal and max temp allowed, toggle auto re-ignite. When enabled and in mode 2, if an engine flames out the afterburner will be disabled and the FC will automatically attempt to re-ignite the engines for 3 seconds. If after 3 seconds the system cannot self recover ALL GAS is shutdown and the engine fault code is displayed. If auto re-ignite is disabled then all gas is shutdown upon any flameout. I'll also include an expert "Overdrive" setting to allow hotter EDF runs when you know you'll be running the engine a lot. OD page will have MaxOD temp, MaxOD Amps with either manual entry or auto 5-10-15% based off the base stats.

 

[mesolost]

It's time. I'm begging for proto type materials over here.
--> http://forum.flitetest.com/showthre...to-type-materials-request&p=189323#post189323