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I want to fly an A-4 at Flite Fest...

Chuppster

Well-known member
The fancy nose took quite a bit of work. It wasn't clear on how to make it work so I made a bunch of bevels.

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It turned out alright. Just kind of a bummer that it will likely end up sticking into the ground at some point and I'll have to remake it.

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Chuppster

Well-known member
I finished the build! It looked alright, not the cleanest, but it's an A-4!

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Then I maidened it...

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Didn't go super well. I had my 2 1500mAh 4s's wedged as far back as possible, and it balanced a little nose heavy, but I gave it a shot anyway. Took off alright but I had to give it a lot of up-stick to keep it from nosing into the ground. by the time I got things situated the craft was a good ways off, and the sky is grey. First time flying in grey skies, you can't really distinguish dark clouds from foamboard...

Anyhow, ended up somersaulting hard. Made a little crater in the field. Looks like I have some major repairs to make.
 

Mid7night

Jetman
Mentor
That looks AWES...::scrolls down::...nnnNNNOOOOO!!! So sorry mate, that's a rough first time out. Given how fast you built this one, I might just start over on a fresh build. Don't give up friend!! You'll get it!
 

Chuppster

Well-known member
Mid7night, what do you think about moving the EDF back an inch or two? There's tons of room in the nose for batteries, I feel like it would be much easier to balance if the weight of the motor was behind the CG.
 
Mid7night, what do you think about moving the EDF back an inch or two? There's tons of room in the nose for batteries, I feel like it would be much easier to balance if the weight of the motor was behind the CG.
Not a bad idea, if you can fit the EDF further back. There's room between the nacelles if you open up the sides of the fuse, but I'd need to look at that closer to figure it out.

Currently, the sides of the fuselage taper in such a way that the EDF can't really go aft any more than it is. But if we cut away the sides a bit there is room.
 

Chuppster

Well-known member
I stared at the wreck for awhile and decided that I didn't want to make another A-4 just yet. So I heated up the glue gun...

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It's amazing what some tape and glue can do. Just had to replace the nose and part of the inlets. Now looking for some clear weather and free time... On the bright side I got it to balance much better during the repair.
 

Chuppster

Well-known member
Finally got some nice weather today! Re-maidened it and it flew! It's a pretty quick jet that's for sure. Got two full successful flights in. The only things I had trouble with is the roll axis (I bumped it up to 100% expo) and the nose dipping when you lower the throttle. The second issue could be related to my EDF being under-powered, I don't know. A suggestion would be to coat the bottom of the wing in tape to help with scrapes.
 
I finally managed to get my A4 buit, looks awesome next to my Viggen and X-29. One problem; I don't know how stupid I was but I accidentaly managed to put a 50A esc in it, only getting about 500g of thrust. Would going up to the 70A I planned on using help with the thrust numbers? Both my other EDFs are at ~0.9-1.1 TWR, this one being a 0.5 is a little scary
 
Yes, putting a properly sized ESC on would certainly help. That said, T/W of 0.5 is still flyable, you just have to keep it moving and you can't go vertical.
 
I am building the Jet , thanks to Ben. I am wondering if anyone did dihedral wings..I dont see it in pictures but there is a gauge in the plan.
Yes, there is dihedral in all my builds. It's not a lot, so you may not notice it in most pictures, but it makes a difference in static stability.

When you join the wing halves, tape their roots together then put glue down the centerline. Then lay one wing flat on a table or floor and put the dihedral gauge under the opposite wingtip, just like Josh does in all the FT build videos.
 

varg

Build cheap, crash cheap
0.5:1 thrust:weight huh? I guess with a plane that is stable and well designed it will fly ok but when I had that kind of thrust:weight with my X31 it didn't end well. Compared to this though it was a very unstable and touchy airplane and once I lost speed in a turn I couldn't power out of it. It's good to have an excess of power because it gives you another way out when things aren't going well.