FOAM BOARD HJK SPEEDWING DISCUSSION
- Thread starter khuzaima
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Piotrsko
Master member
Don't need airfoil if it's solid carbon fiber, BECAUSE it's strong and stiff enough to to not overbend or flutter. You use a shape because it makes things stronger and less draggy and bunches lighter. Drag means you fly slower. Heavy makes you fly slower. Cf is also expen$$ive
yeah probably symmetrical im going to experiment with air foils and see what a type of difference it makes at high speeds gonna make the apex phantom first with air foils and then with ought and see if it has any effect on performence,speed,stability,drag,etc.
I know thats why im building this out of foamboard and not fiber glass or carbon fiber. Cause its expensive (and I dont have the expertise to do so)
makes sense
makes sense solid carbon is very strong so u probably dont need a airfoil but im sure for foamboard u do need one
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well the way I do it is that I first design the air foil and then simply extrude it from there boom wing and Ido this in fusion 360
Piotrsko
Master member
Dunno, I have a couple three flatwing planes without airfoils, but they are light and fast. One has a 3foot span and a 1ft chord (combat flying wing [flip it over and add full down trim for inverted ]) it isn't the upper surface holding the plane airborne, it be the (relative ) higher air pressure on the bottom
Mr Man
Mr SPEED!
Like the FT SpeedWing. (They never made it, I made plans for it.)
I have built a few models and a few have had air foils and a few didn't
alrightttt its been a week now and I have finally gotten serious about building this thing and this is what iv got so far (just started a couple hours ago) Its a similar in size to the MONSTER 1.1 the design isn't perfect and I still have a lot to do but yeah im finally getting somewhere want everyones advice and opinions on this !
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Mr Man
Mr SPEED!
I'll cast my opinion once it is a bit farther underway, hard to say at this beginning stage.👍
alright
Air-headed Aviator
Member
I have fell down the rabbit hole of fast rc planes and have found out about hjk speedwings if u are unfamiliar with these planes let me give u a quick run down,
this is a hjk speedwing this is one of thier biggest models the "Big Monster" I recently found someone who made a foam board version of this plane or at the very least a bunch of similar versions.
this is the tread if u wanna check it out https://forum.flitetest.com/index.php?threads/jh-speed-deamon-a-foamboard-pylon-racer.58734/
this is what it looks like
I love this design and will soon build this my only issue with this design is that its body is a long rectangle I would honestly love it if someone reading this thread would design a foamboard version of the hjk speedwings and make its body a long cylindrical tube just like the body of the BIG MONSTER and then who knows maybe the change is the body shape would mean greater speeds and maybe we can even break the 200 mph barrier with a powerful enough motor. if no one else replies to this thread or no one designs such a plane I will do it myself probably using something like blender,fusion 360 or some other software im posting this thread hoping that this thread might blow up kinda like the speed deamon thread and for know I will download blender and start working on the design.
Hey I recognize that plane! That's a design from Joshua Finn, his foamboard hotliner. He actually made a big one to attempt the first foamboard design to break 200 mph. This is the flight of the plane here.
yes it is the design from Joshua Finn but sadly he didn't really break 200 mph
And another question for u if my prop pitch speed is 218 km/h does this mean I wont be able to go faster then 218 km/h right ?
Mr Man
Mr SPEED!
Correct, consider it 70% with the drag. (The faster you go, the more drag there is to deal with)
Alright nice to know and you know I kinda wanna ask how do I calculate the size of the horizontal and vertical stab the wing span is 160 cm and the length is 115 cm so was just wondering how I could calculate the length and width of the horizontal and vertical stab until I figure that out or someone figures it out for me im not gonna be able to design the plane any further.
Mr Man
Mr SPEED!
Hmm, with mine I guessed by what looked right.😂
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