Large Scale Central

Vader Loco

Modeling
#21

I’m concerned that pulling air from above, the unit may have an unfavorable reaction of lifting the power unit causing instability at higher speeds. It may be a problem on turns. If you could pull the air in from the front, then you would have pulling forces and pushing force to utilize more of the kinetic energy of the fan. Try to pull the air in on a horizontal plain equal to the length so it tends to travel along the track. Also if you could mount a swivel air intake to turn in the direction of the travel it would tend to pull the nose around the turn. David

mike miller said:
Today - Mid build re-design.

(http://freightsheds.largescalecentral.com/users/jtmsmike/_forumfiles/may6-1.jpghttp://freightsheds.largescalecentral.com/users/jtmsmike/_forumfiles/may6-2.jpg)

#22

Since I will be using an electronic speed control and am able to throttle up slowly, lift off will not be a problem. 52mm Ducted fan produces ~ 5 lbs thrust at full power (3500 rpm - 11.1volts/8amps). I ran this by my cousin who was USA Radio Controlled Flying National Champion in 1986. He is also “thinking” about a potential solution to the “no brakes” situation for me. His garage in Texas looks like the Air and Space Museum in DC. My Vader will weigh in at about 3lbs. Given the almost non-existent rolling resistance, I don’t image needing enough throttle to fly like a bird being in the mix. There is a potential for 85 mph but like an expensive Italian car, nowhere to “blow the carbon out”. But thanx for your comments and thoughts.

#23

No Brakes Problem - Improvised, adapted and overcame the problem. Servo mounted to truck with a brake pad that engages rear side of wheel when actuated. Added 1.5v power to run two or three highly direction LEDs for "driving Lights. They also will utilize servo control.

(http://freightsheds.largescalecentral.com/users/jtmsmike/_forumfiles/Brakes.jpghttp://freightsheds.largescalecentral.com/users/jtmsmike/_forumfiles/Brakes-elect.jpg)

#24

BTW…everything is removal for maintenance. Brackets and mini-screws and in the case of the Li-Io Battery, good old rubber bands.

#25

Well this is where I am at today: Motor & Ducting Assembly installed and fan connected to Electronic Speed Control, Skin is fitted (needs some touch up on the anti-reflective finish), Canopy mounted. It is hard to photograph as the flat finish does show details well. Stealth I guess. Need to finish 2.4GHZ receiver connections and wire light control servo and BAM! Almost ready for first “flight”!

(http://freightsheds.largescalecentral.com/users/jtmsmike/_forumfiles/skindone1.jpghttp://freightsheds.largescalecentral.com/users/jtmsmike/_forumfiles/skindone2.jpg)

#26

Love the cockpit. You need cow kill marks on it or something…

#27

Looks mean!

#28

It Works. Now gotta finish the details and get up to the test loop in Lake Arrowhead. [youtube]http://www.youtube.com/watch?v=rsgSgApds14[/youtube]

#29
mike miller said:
It Works. Now gotta finish the details and get up to the test loop in Lake Arrowhead. http://www.youtube.com/watch?v=rsgSgApds14>http://www.youtube.com/watch?v=rsgSgApds14
Cool. Fixed the link for you. Ralph
#30

Thanks Ralph. I am really stoked. tethered it with a couple of rubber bands so I could throttle up…Boy oh boy! Got lots of thrust. Going to have really be careful not to have a “too much locomotive for the engineer” event!

#31

I wonder if the Del Oro Pacific would let me make a run around the outside loop at the BTS? LOL! Backblast might mess stuff up though…Have to be off center and havf some fun once in awhile.

#32

Looks like the kind of thing that would run on a loop of track with the curve superelevated to 90 degrees… at those speeds you could about defy gravity as long as you kept moving… It reminds me of one of these…

(http://upload.wikimedia.org/wikipedia/commons/thumb/b/bb/Agm-129_acm.jpg/800px-Agm-129_acm.jpg)

(Edited to fix link) Matthew (OV)

#33

LOL! I am a Sr. Manager for a defense contractor, so your picture hits close to home. Way back I worked on the capture team for the Global Hawk UAV. We make the sensor suite, EO/IR and the synthetic aperture radar. Vader is very stable in tethered power runs ups. I was concerned about motor torque but there is none. Haven’t gone to 100% full military power (no AB sort of like the F-117) yet. I don’t think it will ever see more than 50-60% throttle as I don’t have a long enough straight run available and then I have to slow it down before any turns. I don’t know how well my mechanical brake will work at speed. It can hold Vader in place up to about 30% throttle. Now that I am done with this toy, I can venture back into the fabrication of buildings. Got the Lassen Freight Depot in-process. John Miller will be pleased with that I would guess.

#34

Mike:

Did you consider an aero brake. Put the ESC / motor in reverse and it should stop pretty quick.

Patiently awaiting pix!!

Happy (ducted fan) RRing,

Jerry

#35

Now that the V3000 successfully completed testing, it was inducted into the Black Dog Skunk Works for application of a Fire Enhancement Program (FEP) modification. Pictures and video will follow as it make actual runs on a loop.

#36

BTW another technical item: 3 Pole DC Electric motors can not be reversed when controlled by a Aircraft RC transmitter. Checked with my Subject Matter Expert (SME). In light of that, no reverse thrust via the throttle.

#37

Well, what about using a servo and setting up the mechanics so the entire motor/rotor assembly spins around so the fan such air in the back and blow it out the front? All with the rotor still spinning in the same direction.

#38
Jason Gallaway said:
Well, what about using a servo and setting up the mechanics so the entire motor/rotor assembly spins around so the fan such air in the back and blow it out the front? All with the rotor still spinning in the same direction.
Spinning it around might very well blow the locomotive over...................................... Ralph
#39

Ralph is absolutely correct. Put about 15 minutes on the test loop up in Arrowhead today, Weather cut the session short so no video yet. Think I am going to upgrade with bearing wheels and take slop out of truck to frame mounting via telflon washers to eliminate body roll and pitch. Rubber wheel bands for brake traction would be nice but do not want to give up flange depth on rail head. And also gotta check wheel gauge width. It is quite a contraption to see whirring around the loop. Can’t wait for the lower loop to be completed. Will be > 200 feet long.

#40
mike miller said:
and take slop out of truck to frame mounting via telflon washers to eliminate body roll and pitch.
Might want to leave a little in one truck to kinda-sorta give 3-point suspension for dealing with less than glass smooth track.