You need strobes. They used to disguise airplanes by putting a row of white lights on the wing edge during WWII so they could sneak up on enemy submarines, as cameo it was very effective.


I would experiment with various low power high intensity LEDs to see what colors show up best.

 

I loaded up the software and the approximate amps at 75% throttle is 18.7 which gives 9 minutes of flight time. At 100% throttle it is at about 28.4 amps which gives 4.26 minutes of flight. Given I would not fly at 100% but for a few seconds at a time it should fly around 7 minutes. These are worse case numbers as I could not find the specs for the exact fan unit in the airplane. The unit I used for the program is comparable in size but rumored to put out more thrust. So maybe the amps will be closer to 25 than 28 at full throttle. Plastic turbine is spinning somewhere between 40,000 to 45,000 RPM. The speed controller is rated for 30 amps so I probably would not want to exceed 2 amps total for the LED system (navigation lights and afterburner combined).

EDIT - I just remembered that I have an onboard flight recording device that will measure various parameters throughout the flight including voltage, amps, and RPM. I'll hook that up later this week and run a static test on the little turbine to find out how much it is gobbling up from the battery.

 

So preliminary calculations show you could be in the clear...though cutting it pretty close. haha

 

An ordinary LM7809 voltage regulator fails to regulate when its input drops to less than 11V.
You are wasting a lot of battery power. You have enough voltage to connect a few LEDs in series so the total current is less.
I think an RC electronic motor speed control circuit will dim LEDs that have a current-limiting resistor.

 

You could use a 5v regulator. one with about 1.5A
You most likely won't be able to connect in series though.

 

You could use a 5V regulator. one with about 1.5A
You most likely won't be able to connect in series though.

A complete waste of power from the battery. The wasted power makes a lot of heat.
The battery has a voltage high enough to allow a few LEDs in series so that the total current is much less.

The jet flies extremely fast and is too fast for me. My ultra-micro P-51 Mustang is fast enough.

My ultra-micro Piper Cub flies as slow as 10mph with no wind and usually hovers like a helicopter with a small breeze. I run around the park with it and so do all the neighbourhood kids. Yesterday I was out-manouvering a hawk! It has hit me (landed) on my belly many times with no damage.

 

A complete waste of power from the battery. The wasted power makes a lot of heat.
The battery has a voltage high enough to allow a few LEDs in series so that the total current is much less.

The jet flies extremely fast and is too fast for me. My ultra-micro P-51 Mustang is fast enough.

My ultra-micro Piper Cub flies as slow as 10mph with no wind and usually hovers like a helicopter with a small breeze. I run around the park with it and so do all the neighbourhood kids. Yesterday I was out-manouvering a hawk! It has hit me (landed) on my belly many times with no damage.

So you mean no regulator at all?

 

I hooked up the data logger and took some quick stats. At wide open throttle it is using 24 amps and spinning at 50,000 RPM. So it looks like I have more room to play with than first thought. Although the static load my be different than the dynamic load, I'm guessing it won't be too far off.

So some are thinking to use no regulator and just run the LEDs in series off the speed controller? Doing that would give a voltage range of 0 to 12.6 early in the flight and 0 to about 9.5 near the end of the flight.

AudioGuru - I have a SlowStick that I can also hover in place with a gentle breeze. It is fun when you just want to relax and not worry when flying. I've aways wanted a fast airplane so this is my shot at one. The kit was very cheap so not a lot of money invested in it. If my eyes and mind can keep up with the airplane is still to be determined.

 

So you mean no regulator at all?

LEDs work with current, not voltage. If you add a current-limiting resistor then it converts changes in voltage to changes in current for the brightness of the LEDs.
You can add a few LEDs in series and in series with a variable current circuit or add a series resistor as a max current limiter and vary the voltage for the brightness of the LEDs.
The circuits do not need a voltage regulator.

 

I might have to get one of these. hehe.
How cheap is cheap?

 

If you live in a civilized country and have a job then almost all name-brand electronic parts are inexpensive. No-name-brand parts are cheap.

I bought some small metalized plastic film 1uF/5%/50V capacitors for $1.00 each but who cares about a dollar?

 

If you live in a civilized country and have a job then almost all name-brand electronic parts are inexpensive. No-name-brand parts are cheap.

I bought some small metalized plastic film 1uF/5%/50V capacitors for $1.00 each but who cares about a dollar?

I meant the 177mph airplane.

 

The 100mph one you can get for $149. Better start there, then upgrade the turbine when you train your brain to function fast enough to control the thing without SLAMMING it into the ground... or Audiogurus belly.

Imagine trying to land one of these on your gut:
http://www.skymasterjet.com/index2.htm

Here is a bunch of those jets for under $200us (far under)
http://www.ductedfans.com/jets_electric_kits_1.html

 

Those jets are too fast (and too noisy) for me.

My ultra-micro P-51 Mustang goes fast enough and can climb vertically.
My ultra-micro Piper Cub flies slower than I can run.

Today I bought an ultra-micro helicopter that is difficult to fly until I learn how.
They all are controlled at 2.4GHz.

 

I might have to get one of these. hehe.
How cheap is cheap?

Jet kit on sale was $79.99. Comes with brushless motor, speed controller, and fan unit. So that is a good deal. However, you need other parts to complete the kit that will drive up the cost a lot if you don't already have them. You need 3 cell LiPo battery packs ($15 to $50 per battery pack), LiPo battery charger ($50), Radio (transmitter and receiver $50 to $500 depending on how fancy you want to get. I use a Spektrum DX7 radio with AR6110 receivers in the airplanes. Also use it to fly my helicopter. It is $300 but something like a 5 channel DX5 for $100 will be fine for most airplane use.) , 2 servos ($10 to $30 per servo), and some epoxy. I have a few airplanes that I mothballed so I didn't have to buy anything other than the $79 kit. Otherwise you are looking at an additional minimum around $150 to get started, but closer to an extra $250 to get started using medium quality stuff versus the cheapest stuff.

However, if you have not flown remote control airplanes before, you do not want a jet as your first airplane. My guess is that it would crash and be destroyed in about 5 seconds from launch. Typically you start out with something like a high wing airplane (Cessna) with dihedral in the wing so you can let go of the controls and it will level out and keep going straight. Then when you get practice with that you move to something more aerobatic and little or no dihedral. Finally you would fly something like these small jets with tiny wings akin to fins on a missile. Typically jets are very maneuverable and geared for experienced flyers. Flying wings are a good intermediate step before jets because they are fast, very maneuverable, can also fly slow, and are extremely crash tolerant.

If you already fly and know this stuff then forgive the long post. I just don't want to cause anyone to go out and get into this hobby with the wrong first airplane. It is very fun but if people start with the wrong airplane they will quickly get discouraged due to the crashes and expense of repairing the damage. I really recommend people who want to get started to first buy a flight simulator program that can connect to a RC radio and to practice a lot on the PC before trying to fly the real thing. Also, it is a very good idea to find a local club or flying field to get someone to take off the first time, trim the controls, and help out in the first few flights.

When my foamy F-16 grows up it wants to be one of these!
http://www.youtube.com/watch?v=tLlBCrLODo4

I love that sound...
http://www.youtube.com/watch?v=yDPjdu5MThk&feature=related

Here is the info on the turbine in that jet. A deal at $5,295 (for the turbine alone.) 112,000 RPM, 52 pounds of thrust, and thirsty 24 oz of kerosene per minute.
http://www.jetcatusa.com/p200.html

 

Those jets are too fast (and too noisy) for me.

My ultra-micro P-51 Mustang goes fast enough and can climb vertically.
My ultra-micro Piper Cub flies slower than I can run.

Today I bought an ultra-micro helicopter that is difficult to fly until I learn how.
They all are controlled at 2.4GHz.

Let's see some LEDs on those things. Post photos!

 

Not to try and throw you a curve, but I was in the Navy which doesn't have F-15's or F-16's. But I've seen many F-14's, F-18's and old F-4's and I do believe that at night the afterburners burn Blue to white, if you're looking for realism.

Flames from coolest to hottest, yellow, orange, red, blue then white.

Have fun, That F-15 flight looked pretty cool; Good Pilot!

Later

 

Not to try and throw you a curve, but I was in the Navy which doesn't have F-15's or F-16's. But I've seen many F-14's, F-18's and old F-4's and I do believe that at night the afterburners burn Blue to white, if you're looking for realism.

Flames from coolest to hottest, yellow, orange, red, blue then white.

Have fun, That F-15 flight looked pretty cool; Good Pilot!

Later

I noticed at full afterburner the real ones do tend to look white / bluish. At the lower settings more of an orange glow. I'll have to settle for just partial afterburner on my foam jet. Anything more might rip the wings off and melt the plastic tail cone. LOL. Hoping my LEDS arrive soon so I can start working on the project. For now to keep me busy I'm going to glass the bottom of the airplane. Adds a little weight but holds up a lot better than styrofoam alone.

 

I land my RC airplanes on their wheels on a paved parking lot. Touch and and goes are also fun.
I also land them with a little stall then plop onto the grass in the park.
No damage to the bottom.

 

Is there a way to change the title of the thread to "Need help with LEDs to build afterburner for model?"

I cheated!

I found a light navigation system on sale for $13 that has 3 nav lights (with a red and green that strobe), a bright landing light, and an afterburner ring. So I thought this will save me $ and eliminate the need to completely reinvent the wheel.

Now here is where you guys come in. The LED ring is too big, so I need to cut it and make it smaller, or even better, once my LEDs arrive I may use them to make a custom afterburner ring fit to size. I think my yellow and red LEDs will also look better that the red ones in the ring now. So before I burn or short something out, I'll seek guidance here for the right way to do it.

Looks like all the LEDS are hooked up together in a single series and there are only 2 wires going to the ring. There is what appears to be a voltage regulator on the power cable to the battery. The "manual" calls the cable to the PCB a "same voltage amount battery cable." There are two varistors. One controls the amount of servo travel needed to turn the nav lights remotely on and off. The other controls the brightness of the LED ring.

One possible issue I identified is that when you set the afterburner LEDs to max bright on 100% throttle, when you go to 0% throttle they are still illuminated, but dimmer. If I set the varistor so that a 0% throttle the ring LEDs are off, at 100% throttle they are only at about 75% brightness. I still have to play with possibly setting up a custom mix on the radio so that another channel controls the afterburner LEDs so they do not turn on until at 75% throttle. But I don't think that will solve the issue of them not fully turning off if they are set for max brightness at 100% throttle.

For the low price I can't complain. Not perfect but I can try to tweak it later. Here are a few photos: