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50mm EDF Tailed Delta Project

Vimana89

Well-known member
#1
This will be the thread for my first EDF build. I've slowed down the fevered pace of my prototype building and testing different custom designs a lot since most of my planes work now, so I'm focusing on more ambitious, high quality projects that take a bit more time to develop. I'm stoked about this one! It will be using the FMS 50mm 4500kV they sell in the FT store, along with 40a ESC on 4s with a 1000mAh battery. This setup will get me a whopping 850g of thrust on 4s. I decided to do a delta of my own design, since deltas benefit well from a ducted fan and are something I'm comfortable with. I decided on a somewhat low aspect tailed delta like the Arrowhead over a more basic delta like the Vulcan or and ultra slender tailless design, because that is what I feel is my most well rounded and capable design so far...however, It would be a tiny bit overpowered on a standard sized Arrowhead, and I wanted to go a bit bigger.

The only way to really go bigger and keep a light, simple single sheet wing with 20" span is to go longer. The current Arrowhead has a 20" by 20" wing, and my current slender delta has a 15" by 30" wing. I want to stretch the wing of this new plane to 20" by 30", giving it the same span as the Arrowhead but more chord length. I will retain the tail plane and winglet features basically they are on the Arrowhead. This bird will have a slightly longer box fuselage made of two telescoped boxes to get the same or greater length between the wing and tail surface, and a nice pointed nose(probably something simple and four sided). The EDF and thrust tube will be on a nacelle on the back/top of the wing. It will probably sit by the rear of the wing and possibly all the way back onto the back part of the fuselage. This is to keep it elevated from dirt and gravel and for some thrust over my elevator.

I have the components coming in the mail aside from the ESC which I had laying around from buying parts in my newb days. I want to use black papered DTFB if I can snag some and make this nice and clean, even the prototype. It won't necessarily be perfect but want all the lines straight and nothing wonky looking, so I'll take my time a bit more on assembly. I though of going 4ch for my first EDF, but will hold off on the rudder and perfect my 4ch on simpler prop planes and my EDF on 3ch first. I plan to make my thrust tube either straight or with very little taper, maybe 5% if any as I'd like this first prototype to have good static thrust, and top end isn't such a problem with all that power. I'll be looking at a 40-45"ish overall length ship including the tail plane that will weigh about 400g or so with a setup that puts out 850g of thrust.
 

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Vimana89

Well-known member
#8
I'm really looking forward to getting into this build, and I'm excited to get this design in the air and see what it can do. I'm stoked to see all the anticipation and interest! I'll do my best to share the process a bit more in depth than some of my more basic/spur of the moment designs. The plane itself, aerodynamically speaking, should be perfectly sound. Not only that, It'll be predictable in terms of CG and handling. It will basically be a slightly bigger and much more powerful version of the Arrowhead, with a little bit of the characteristics of more slender deltas mixed in. The real deal that will make or break this is probably how I go about setting up the EDF.

I think I've got a pretty good idea of how to go about that. If I'm not mistaken, I'll want a thrust tube that has a length of 4x the diameter of my EDF. This should be 8" for a 50mm. I'll make mine out of poster board like they show on the Viggen video, and I'll make my nacelle/housing a square A or B fold box(for simplicity and strength) with little brackets with 50ish mm round holes to mount the EDF and thrust tube inside. The power pod will be simple and fixed with a couple tabs and slots and glue mounting it on. I will either use a 0% or 5% reduction in exit hole diameter for good static thrust.

I've got motor extension cables that should reach long enough to give me a lot of options of exactly how far back I want to mount this thing. Things to balance and consider here are CG and thrust wash over my elevator. Flying should be fine if I get everything right, as long as I take it easy on the speed until the plane is trimmed and dialed in right. I'm looking forward to see the roll rate on this ship with a bit of speed...axial rolls should be great, and she should fly straight as an arrow in forward flight. High alpha should be a breeze too with all that thrust and low torque. I'll update soon when I get the foam and parts and start making some progress.
 

jfaleo1

Junior Member
#9
I'm really looking forward to getting into this build, and I'm excited to get this design in the air and see what it can do. I'm stoked to see all the anticipation and interest! I'll do my best to share the process a bit more in depth than some of my more basic/spur of the moment designs. The plane itself, aerodynamically speaking, should be perfectly sound. Not only that, It'll be predictable in terms of CG and handling. It will basically be a slightly bigger and much more powerful version of the Arrowhead, with a little bit of the characteristics of more slender deltas mixed in. The real deal that will make or break this is probably how I go about setting up the EDF.

I think I've got a pretty good idea of how to go about that. If I'm not mistaken, I'll want a thrust tube that has a length of 4x the diameter of my EDF. This should be 8" for a 50mm. I'll make mine out of poster board like they show on the Viggen video, and I'll make my nacelle/housing a square A or B fold box(for simplicity and strength) with little brackets with 50ish mm round holes to mount the EDF and thrust tube inside. The power pod will be simple and fixed with a couple tabs and slots and glue mounting it on. I will either use a 0% or 5% reduction in exit hole diameter for good static thrust.

I've got motor extension cables that should reach long enough to give me a lot of options of exactly how far back I want to mount this thing. Things to balance and consider here are CG and thrust wash over my elevator. Flying should be fine if I get everything right, as long as I take it easy on the speed until the plane is trimmed and dialed in right. I'm looking forward to see the roll rate on this ship with a bit of speed...axial rolls should be great, and she should fly straight as an arrow in forward flight. High alpha should be a breeze too with all that thrust and low torque. I'll update soon when I get the foam and parts and start making some progress.
Just remember EDFs are not props or turbines. You still have torque but you also get a slower rate of acceleration, so keep power on during approaches until touchdown and power up smooth don’t just stab the throttle. Your design should be awesome.
 

Vimana89

Well-known member
#11
Does your tx have a throttle curve? If it does, would like to show you a tip that can prevent a possible crash during the learning process and/or when you fly.
I use the FSIA6, can't recall just from the user manual but a quick search tells me that yes, my TX does have throttle curve settings. This isn't something I've messed with before but I'd be able to figure out how to change the settings if I needed. What do you propose?
 

L Edge

Well-known member
#12
As jaleo1 mentioned about power on landing, here is a neat way to help you. I learned this trick from a world's champion, EDF's at the low end have very litle power at low rpm's. So, what you do is bump up the speed at the lower end and if you need a go around, it's less time to get power to it. Or it keeps the power up slightly to smoothen out the approach and flairing. I never shut off until I land.

IMG_0311.JPG


By adding extra points , you are able to take a straight line and bump up the rpm's at the low end. Here is a video and turn up the sound as you can here me massage the throttle to control the approach and I estimate I am on the low side of pt 2 to almost pt 3 for approach and landing.


Also, suggest you get a yaw control built in yours. Otherwise with winds, it will control you. Notice the sharp turns I get with TV. It is 3Dimensional world.
 

Vimana89

Well-known member
#13
My order from FT has been shipped. The first time I looked it said the EDF unit was in a different position in the "supply chain" than the rest of my order. Hopefully it caught up and they shipped it with the rest of the stuff. I believe that should be the case otherwise they might have said something. Still have to find a dollar store that has the black papered foam in stock, but I got plenty of white if necessary.
 

The Hangar

Well-known member
#14
My order from FT has been shipped. The first time I looked it said the EDF unit was in a different position in the "supply chain" than the rest of my order. Hopefully it caught up and they shipped it with the rest of the stuff. I believe that should be the case otherwise they might have said something. Still have to find a dollar store that has the black papered foam in stock, but I got plenty of white if necessary.
Why do you prefer the black? I find the paper comes off too easily for my taste...
 

Vimana89

Well-known member
#17
I'm looking forward to this. A little scale and variation seem to be no problem for the tailed delta concept. I think I'll love it as an EDF too. I'll look into adding those settings for throttle curve when I get a chance. I'll check out specifically some information on how to do it with the IA6. If I have some trouble I may just make it a priority not to land below a certain level of throttle. In that even I'll check to see the minimum required to keep it from stalling while it's higher up, and go from there for a landing approach.