DIY EDF plane & pictures

[Sunstorm]

Of course it's more fun. Thanks!

[Babylon5]

Hey Babylon5, you tried flying invert already or not? Check CG flying sideway or upside down and see what the plane does.

Up down Thrustline check is done by neutralising your elevator, fly fast level and pull into a vertical climb(orientate yourself so you can be sure it is pointing upward), see if your plane pitches up or down.

CG whether optimal is very easy to check. If you have a lot of elevator reflex, this is a sign of nose heaviness already. When flying slow, that reflex position is enough to hold a level flight but when you go full throttle and achieve max speed with your model, that same amount of reflex is going to get more effective and put your model into a climb.

So please do these checks and tell us what you see the model doing in the air. The methods you are using now not going to tell you much. My AJ is neutral CG (3D plane) and when landing with no throttle, I may pull as much as 45 deg elevator as the point of touchdown to be level, but that doesn't mean my plane is nose heavy. That is just because I am stalling the bugger and am pushing the envelope of its glide characteristics.

Hi Edmond, thanks for your feedback. I will try inverted flight this weekend and see how is the flying characteristics.

Meanwhile, have anyone try a twin EDF setup on the Mugi...just curious?
My initial estimate on the wing loading for a twin is 15 to 16 oz /sq ft vs 12-13oz/sq ft for a pusher on a single EDF.
(Sorry I am use to the FPS or imperial units)




Cheers

[Sunstorm]

twin fans = ??

Hello b5.
I have no clear idea about all this terminology.

But 1 thing I must tell you

an 80 cm span mugi with 1 55mm EDF weights about 500 - 600 gms with batts for me. That's using 2mm coroplast.

Not sure if you using 2mm or 3mm - yours would weight more.

For me, a 2040 motor and duct set weights about 100 gms. That's what I assume you are using.

so for twin setup - it's 200 gms rearward weight.

Considering that if you use a 2200 batt; it would be 165 gms

The mugi already is tail heavy unloaded;

So 1 battery balances 1 duct.

If you are using 1 battery to 2 ducts, you might have to put a tonne of weight in the nose, or use 2 2s batts

or shift the duct fans to the centre of the craft, like in the middle, if its a regular sized Mugi.

This would make the mugi look really ....weird(my opinion)

Plus, if you play around with the wing loading, it might really make the mugi 700 gms or so with 2 ducts and battery to balance it. That's really heavy which means you need bungee or elastic, which is unecessary if you had stuck to 1 fan.

Some hope though;

you can use the pencil thin motors and GWS 40 mm ducts. Twin feigaos ought to bring it to a decent performance, but not much verticals, I would give it.

you can upscale the mugi to 1.5 times (1.2 m span) and put 2 55mms on it, along with a 4s 2500 battery or so; 1 fan = 350 thrust , so 2 = 700 gms thrust

Larger span gives some leeway to play around with, instead of stressing yourself over squeezing everything into this dinky 80 cm span.

But like everything else, it's just my opinion. Maybe you can do a cool one with twin fans that blows everyone away?

Later on, I might / just might do one with twin setup... but it's highly unlikely seeing how expensive feigaos are and the complications of wiring EDFs.

I got a lot of sketches, but nothing done.

[edmond22]

Hi Edmond, thanks for your feedback. I will try inverted flight this weekend and see how is the flying characteristics.

Meanwhile, have anyone try a twin EDF setup on the Mugi...just curious?
My initial estimate on the wing loading for a twin is 15 to 16 oz /sq ft vs 12-13oz/sq ft for a pusher on a single EDF.
(Sorry I am use to the FPS or imperial units)




Cheers

I tried twin setup on the Aeroswift wing before but never on the Mugi. I did not see much improvement in flight because the gain is taken away by the additional weight. It depends on Setup I supposed, you will good batteries to support those 2 motors. It does however penetrate wind better due to increase wing loading.

[Babylon5]

Hi Edmond, your estimate of the twin 2x55 mm EDf with the wood mount comes to 195gms...very close to the estimate of 200gms.
I have static test that the 2x55mm EDF could lift a load of 760grams(probably lift more load if one use a good lipo batt that can discharge and maintained the voltage at high current) vertically once the impellers are properly balance and matched with 20 mm diameter long can size mtr.

Just an after thoughts....Am also thinking of increasing the wing span for future Mugi.
If I increase the WS from 0.8 to 0.9metre the wing area would have increase from estimate of 240sq ft to 360 sq foot ...which is a good wing area for a 2x70mm EDF setup or a single 90mm EDF setup.



Cheers

[Babylon5]

Sorry 240 sq ft should read 240 sq inch ...otherwise this wing area could fly me around in it. Ha ha ha.

[edmond22]

hey B5,

for EDF right, I am usually looking for top end speed and this is the same top end speed that allows me some good degree of vertical climb. So you might want to evaluate your exhaust efflux speed too, achieve a good one and you will like it.

[Babylon5]

Mugi Twin EDF maiden's

Manage to sucessfully maiden the twin EDF conversion of the Mugi DIY plane

see link.

http://www.youtube.com/watch?v=fHQNqdhHFSU

....and a couple of other Mugi plane a twin ,Single & a Pusher pictures.
(The pusher belongs to a friend and also maiden sucessfully today.)

Most of the flight I flew at half power. Plane tracks pretty good at max power
...just a slight climbout.


Cheers

[Sunstorm]

Amazing. Looks fierce...

[Babylon5]

Did you guys try to fly upside down and determine your if your CG is optimal?

Do that and perhaps learn something about your setup. My bet is that either your thrust angle is off or your CG is not optimal. I am betting you will need a lot of push elevator to fly level inverted.

Hi Ed, I tried the inverted flight on the single EDF version and i have to push forward more when the Mugi is inverted position.
The same goes for the twin Mugi so looks like I may have to play around the down thrust angle and move the c.g.location a tag .
At the moment the Elevon is 1-2mm up at neutral.


B5

[edmond22]

Hi Ed, I tried the inverted flight on the single EDF version and i have to push forward more when the Mugi is inverted position.
The same goes for the twin Mugi so looks like I may have to play around the down thrust angle and move the c.g.location a tag .
At the moment the Elevon is 1-2mm up at neutral.


B5

Shift your CG bit by bit first aft till you need a little push to fly inverted level. That should take a away excessive reflex you may have at the elevon (1-2mm). Btw 1-2m doesn't sound like much to me though, so prob have to take into account that it is a semi foil which doesn't work quite as well inverted. For thrust angle, use the vertical method to check, dun adjust it to fly level or you will find that it will cause you other problems.

[Babylon5]

hey B5,

for EDF right, I am usually looking for top end speed and this is the same top end speed that allows me some good degree of vertical climb. So you might want to evaluate your exhaust efflux speed too, achieve a good one and you will like it.

Hi ED, you are right again I am exploring a better exhaust Efflux setup with some very interesting flying characteristics.
The twin EDF Mugi seemed to be doing fine after re-adjustment of the c.g.
it is fun to fly the twin Mugi setup. It is almost 100grams heavier than the single EDF but hand launch is very easy and straight forward.
Am now looking forward to built a larger twin version or a single 90mmEDF mugi.

Cheers

[Tanbenson]

Will this fly?

Hi Guys,

Have some crazy ideas a while back, not sure if it will fly. Currently on 1/2 build.


Thank you for viewing.

Happy and Prosperous New Year to ALL.

Best Regards.

[Tanbenson]

Sorry , the picture size to large. Had it resize. Thank you.

Best Regards

Hi Guys,

Have some crazy ideas a while back, not sure if it will fly. Currently on 1/2 build.


Thank you for viewing.

Happy and Prosperous New Year to ALL.

Best Regards.

[viper1990]

Hi Tanbenson...

My opinion is yeah why not, looks pretty possible to me. As long you get your CG correct..., and reasonable wing area to carry the weights of the batt and motor.

Do a test glide first! just throw the airplane with nothing on it and play around with the CG then find the sweet spot.

In the past i didn't bother test glide and added everything on the plane and throw. It either crash or sometimes lucky it glides.

Heres some inspiration i found over at rcgroups. They can make almost anything flies! Haha. just check it out

http://www.rcgroups.com/forums/showthread.php?t=373593

So if they can, why not yours.