Mirage2000 scratch parkjet from parkjet.com

[viper1990]

With some spare time i search the next favourite plane to build, download the plans and start scratch building! Took me about 3days to get this done.
Made out of 5 materials.

1 Plastic bottles for tubing
2 Depron for the body
3 styrofoam for the nosecone and canopy
4 coroplast for wings
5 A4 paper for wrapping the outer EDF tubing (can't figure other ways to cover up the tube )

Wingspan is 70cm,Plane weighs in around 600grams. Pretty heavy for a small plane. Especially its EDF ... i have a bad feeling i can't get enough power to handlaunch it.

I'm going to test gilde/fly it the next few days and see the results. Hope everything goes well!

Ok, here are some pictures...

Constructing the plastic tubing...

Glued the wings to the tube

Constructing the body next.

Finished...

Created a hatch so the edf can be removed easily.

Done!

Front view

Backview


Thats about it so far... Really do hope the plane can fly This plane its not easily constructed compared to my flying wing!

[LouisLLH]

Nice DIY plane bro.

All the best for ur maiden flight.

[Heli_fanatic]

ooo nice .... im not a plane person but this is superb good luck

[Babylon5]

Nice plane bro. May I know what size of EDF you are putting into the plane.

You need to calculate the lifting area of the AUFW plane to get the wing loading equation. This will let you know what kind of wing loading characteristics of the plane.

If the intake and outlet (assuming unobstructed) is reasonably good you could get about 26-32 grams of thrust per amps with a good 3S lipo and a good motor fan combo.
Your estimate weight of 600 grams you may need at least 24amps or over 240watts of power for the EDFsystems to generate enough thrust for a sucessful hand launch.

Good luck and hope a sucessful maiden.


Cheers

[Sunstorm]

Hello b5.

What you said was very interesting.

You mean to say that we must always have thrust more than weight for hand launching?

Your estimate weight of 600 grams you may need at least 24amps or over 240watts of power for the EDFsystems to generate enough thrust for a sucessful hand launch.

Thrust per amp is 26 gm

So 26 x 24 = 624 gm!

So much is needed?

[viper1990]

Nice plane bro. May I know what size of EDF you are putting into the plane.

You need to calculate the lifting area of the AUFW plane to get the wing loading equation. This will let you know what kind of wing loading characteristics of the plane.

If the intake and outlet (assuming unobstructed) is reasonably good you could get about 26-32 grams of thrust per amps with a good 3S lipo and a good motor fan combo.
Your estimate weight of 600 grams you may need at least 24amps or over 240watts of power for the EDFsystems to generate enough thrust for a sucessful hand launch.

Good luck and hope a sucessful maiden.


Cheers

My EDF size is 68mm. Haha, and my motor never exceeds 500grams of thrust... babalon5 was right about 5 bladed imbalance thing.... so i lost quite alot of thrust due to that..,ok Did test glide and it went well, found the CG and ready to fly the next following days

[joe yap]

Nice plane bro. May I know what size of EDF you are putting into the plane.

You need to calculate the lifting area of the AUFW plane to get the wing loading equation. This will let you know what kind of wing loading characteristics of the plane.

If the intake and outlet (assuming unobstructed) is reasonably good you could get about 26-32 grams of thrust per amps with a good 3S lipo and a good motor fan combo.
Your estimate weight of 600 grams you may need at least 24amps or over 240watts of power for the EDFsystems to generate enough thrust for a sucessful hand launch.

Good luck and hope a sucessful maiden.

Again, what makes the plane fly is the air, not electrons.


Cheers

Interesting. My little Viking weighs 375gm All up weight, running on 2S Lipo and 10amps total, and draws about 72-84 watts on cheap brushless motors. Hand launch very well anytime.

Again, what make the plane flies is the moving air, not electrons. The less you understand about how the moving air is turned into useful work, the more power you'll need to achieve the same result.

[salman78]

Wing info

just for my learning.

If you could highlight how you made the foam wings ???

I have made some but they are all rectangular, I need to learn the delta wing configuration !!

[joe yap]

Hello b5.

What you said was very interesting.

You mean to say that we must always have thrust more than weight for hand launching?

Your estimate weight of 600 grams you may need at least 24amps or over 240watts of power for the EDFsystems to generate enough thrust for a sucessful hand launch.

Thrust per amp is 26 gm

So 26 x 24 = 624 gm!

So much is needed?

It depends. If you launch your plane like a whimp, or your plane has very high wingloading, you'll need plenty of static thrust. If you launch like an Olympic Javelin athelete, you don't actually need much.

[Babylon5]

Hello b5.

What you said was very interesting.

You mean to say that we must always have thrust more than weight for hand launching?

Your estimate weight of 600 grams you may need at least 24amps or over 240watts of power for the EDFsystems to generate enough thrust for a sucessful hand launch.

Thrust per amp is 26 gm

So 26 x 24 = 624 gm!

So much is needed?

Hi, brother I mean the chance of success of a hand launch when you have ample thrust to start with .

It does not mean if you have thrust to weight ratio greater than one ,you will always sucessful hand launch the plane ... but you increase the chance of a sucessful hand launch.

If you have less available thrust during hand launch your chances of a sucessful maiden diminishes.


Ducted fan aircraft takes more time to built up its speed during a launch than compare to a larger propeller driven systems.

Other factors of a sucessful hand launch also depends of the type of aircraft like wing loading, aspect ratio and the co-efficient of lift of the aircraft and the aircraft characteristics ...and finally the skill of the person who hand launch the aircraft.

Cheers

[viper1990]

Ya, i agree that the skills of the person launching the plane must be good.


I have a personal experience once, my friend wanted to help be handlaunch my flying wing weeks ago i agreed to let him launch ,showed him the proper way to launch the wing, Grab one end of the wing and throw it like a discus with strength, when its his turn...., i on full throttle and he swings it without any noticeable strength... went into a stall immediately ... and bam! the plane crash. haha!

I always Handlaunch planes with full throttle,never with 3/4 or 1/2 just to not take any chances to fail a lauch. Once the plane gets airbrone, i quickly reduce throttle to half...or even 1/4 and it still fly while maintaining attitude.

So its the Handlaunching part which is the scarist part of flying for me , something could go wrong....

[viper1990]

I haven't madien the plane yet, still pretty worried my plane getting little thrust...

need some help. My 3550kv motor is drawing 15.47Amps on full throttle on 3s.. (i thought it can reach a peak of 26amps) So in total..i only got 195 watts.

it is because its 5bladed thats why the amp draw is lower? So i'm guessing a 6 bladed edf (with same dimensions) will draw a little more Amps with more thrust.

I'm somehow tempted to try on a 4s.... ( 2 of 2s lipo in series).

[Babylon5]

Hi Viper, on the 5 blade 68 or 70mm EDF if blade is reasonably balance(if you are lucky) on 3S Lipo with the Align motor 3550kv should tech around 25-26 amps using a thong clamp ammeters.

Check your LIPO battery "health" and the ESc connectivity and ESC setup.
Don't go for 4S with the current motor KV and fan setup...will be certainly short live.

BTW how did measure the current?

Cheers

[Babylon5]

Hi, Viper, did you got your 5 blade EDF from J.H?
I got mine 5 blade 68-70mmEDF from J.H & C. hobby?
The internal diameter is slightly bigger than the 6 bladed SFM.
I am thinking of replacing the crappy 5 blade to other 3 bladed ...some more experiment first...and will pm you if you are interested to know the result.

Cheers

[viper1990]

I do what you said..., clamp the ammeter in series in between the batt and esc. I program the esc to high discharge. I went to champion hobby to check out whether they sell the 6 bladed 68mm DF, then they ask me come back another day , travel all the way there just to find it not in stock.

I got the duct from rotorhobby, but its the same Ducted fan from jet hobby.

Anyway ,yep i'll be interested to know the result for your 3 bladed test, i also would like to know where can i get 3 or 6 blade to replace the 5 blade. Mine's definately not balanced.