Zoom Master
Elite member
And also how come I cant find any plans online for foamboard jets for say 80-90mm edf's ? Looking to build some sort of fighter jet in the near future and get back into the hobby.
2025 High speed Challenge
Mr Man
Mr SPEED!
Well, probably because most people donāt have the budget to have an edf that big! š. But you could probably scale something up to use that sized edf.
Zoom Master
Elite member
Never have done that before....does that affect how the airplane flys ?
Zoom Master
Elite member
Was thinking about maybe building a 90mm f16 or maybe a twin 70mm edf f15
Mr Man
Mr SPEED!
Youāll need to add reinforcement for sure, but they normally fly pretty good. (Sometimes gentler)
Mr Man
Mr SPEED!
@Mid7night has designed for a 70mm f16, and a f15 I think. (Maybe not the f15 actually, but he has other twins)
Zoom Master
Elite member
Hmm might do that one day but for now I think might just build a 70mm edf f15 when I get the time
Zoom Master
Elite member
Just like this one right here
telnar1236
Elite member
3D printing isn't really all that much weaker than composites if you do it right, and they have a machined aluminum frame, and like they note in the video, it's far far easier to repair and iterate on a design. Back in the late 40s/early 50s the full-scale Vought Pirate hit almost 600 mph with a mostly balsa wood and aluminum airframe, so you don't really need as much structure for high speed as you might think - it's mostly that you need a well designed structure to avoid things like flutter.
That said, as Houndpup RC pointed out the stall speed will be very high. Having flown a similarly sized delta design weighing in at 4 kg with my F-106, it can be a challenge to get that down on a 300' paved runway with its 35 mph landing speed, and that is designed with a conical camber wing specifically made to fly well at slow speeds. I wouldn't be shocked if their stall speed is somewhere around 70-80 mph and they need to take off from an actual airport runway.
I also noticed the trailing link struts on their design seemed to be backwards which was interesting. I've never seen anything designed quite like that, but they seem well designed, and the team seems very smart, so it will be interesting to see how they hold up. It would certainly be convenient to be able to make struts like that on our planes.
That said, as Houndpup RC pointed out the stall speed will be very high. Having flown a similarly sized delta design weighing in at 4 kg with my F-106, it can be a challenge to get that down on a 300' paved runway with its 35 mph landing speed, and that is designed with a conical camber wing specifically made to fly well at slow speeds. I wouldn't be shocked if their stall speed is somewhere around 70-80 mph and they need to take off from an actual airport runway.
I also noticed the trailing link struts on their design seemed to be backwards which was interesting. I've never seen anything designed quite like that, but they seem well designed, and the team seems very smart, so it will be interesting to see how they hold up. It would certainly be convenient to be able to make struts like that on our planes.
Mr Man
Mr SPEED!
I wonder if they could add some aerodynamic landing bay doors. As they left them openā¦
Zoom Master
Elite member
They can its not that hard to add im sure they probably are adding landing bay doors but maybe just didn't show them in the video...
telnar1236
Elite member
It looked like the main gear actually stuck out a little bit which isn't too surprising considering how thin their wing is - and the way they designed the gear bays, they aren't actually adding all that much drag by not having the gear bay doors.
However, on the nose gear, it's a different story. There hopefully they will add one like you're thinking.
Zoom Master
Elite member
If it were me I would put any landing gear at all on the plane seems like the more you add to a airplane that is going that fast the more issues start appearing.....
Mr Man
Mr SPEED!
They did make a belly lander version too.
Robot_Child
Member
You people are absolutely mental! Great challengeā¦ well done
Mr Man
Mr SPEED!
Just curious (so you donāt have to answer) but are you from the UK? (Iāve heard a lot of British people say āmentalā so just wondering š)
Robot_Child
Member
Nope. Iām Australian mate. Anyways, this isnāt an entry but it is fast. Enjoy my arrow doing a fast pass. I had to thread the needle under a power line behind the cameraā¦
iCloud Photos - Apple iCloud
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share.icloud.com
I couldnāt work out how else to share it so hereās an iCloud link lol
Houndpup Rc
Legendary member
I wanna build it! š
Houndpup Rc
Legendary member
I honestly would go belly lander to keep the AUW weight down..Also, one tiny mistake in landing and those retracts are going to be toast! š
Houndpup Rc
Legendary member
Yup, that's what I thoughtš (I think Australia is cool!š)Nope. Iām Australian mate. Anyways, this isnāt an entry but it is fast. Enjoy my arrow doing a fast pass. I had to thread the needle under a power line behind the cameraā¦
iCloud Photos - Apple iCloud
View, organize, and share photos and videos with iCloud Photos on the web. Changes will sync across your devices with iCloud.
I couldnāt work out how else to share it so hereās an iCloud link lol
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