The Stiletto - a Simple Push-Pull Delta

[Yusernaym]

Today I started on a scratch build that I'm thinking of calling the Stiletto. It's my first original plane, and it is very small - less than a foot long, less than a foot wide. I'm using a power pack a for now, but if that's somehow not enough power for this thing, I have a 2700kv 2207 that'll fit, which should be plenty. The cg is maybe a little to the back, but I can figure out how to push that forward tomorrow. The solid single piece wing is ridiculously strong. I was planning on working a spar into it, but the laminated layers are plenty from what I can tell. All that's left are installing servos, cutting elevons, figuring out a tail, adjusting cg, and maidening it. I might just be able to get that done tomorrow. If it's successful, I'll be making plans for sure. It's a simple, light plane that can easily be made from one sheet of foamboard, even when prototyping and taking multiple tries at individual parts.

 

[Merv]

Looking good

 

[Timmy]

Agreed

 

[Ranger_107]

looks cool

 

[Mr_Stripes]

You said delta... is it going to have a rudder?

 

[Yusernaym]

You said delta... is it going to have a rudder?

It's going to have a vertical stabilizer, but I think I'm going to stick with elevons for now just for simplicity. I don't know if that makes it a true delta, but that's the idea I was working with

 

[Mr_Stripes]

Well I suppose ill just mod it a bit

 

[Yusernaym]

if you don't mind, could you explain why it needs a rudder to count as a delta? I googled it and didn't really get an answer

 

[Mr_Stripes]

I dont know I just always see deltas as a wing with a rudder.

 

[Yusernaym]

Okay, that seems to be the accepted definition. I was thinking of doing a double vertical stabilizer, which would complicate adding a rudder. However, I've been improvising the whole time anyway, so I'll just add some more support to the center section at the back and work in a single.

 

[Mr_Stripes]

That would be cool. Maybe make an option.

 

[flamingo]

looks nice

 

[BATTLEAXE]

Delta's don't need a rudder, its not necessary for stable flight. Actually if anything it could just complicate things. If this is a V1 I would say leave it out and add it later if you choose

 

[Yusernaym]

okay, update time. I had to add a lot of weight to get the cg close to where it should be, so the next revision is going to have a longer pod section for sure to get better leverage. I did some glide testing, which went well, and one attempt at a powered launch, which did not. She twisted way more than I was expecting, and ended up hitting nose first. I have since added more weight, which should help a little, but I think some more vertical stabilization would help as well.

 

[Flyer Sean]

torque roll will be hard to overcome on this little plane. You could try it as a twin pusher or launch it straight up letting it twist until its got enough speed for the control surfaces to work. Ive made a few small deltas and most of them just spun out on launch

 

[Yusernaym]

Big update: V0.1 is done.

Had her first flights, and many crashes. The first version flew, technically, but it was only stable in the initial high alpha and any attempt to pitch out resulted in some combination of a spin, stall, and dive which resulted, predictably, in a crash. The causes of the trouble on those flights are good lessons, including that the plane was too heavy for it's wing area, and was still tail heavy. Already moving on with revisions, 0.2 will be longer, designed to be better balanced, and hopefully lighter.

So far I have the wing, new pod uprights, and an idea of how things should balance. According to online wing cg calculators, the balance point should be 7.47 inches from the front of a 16 inch long wing, which seems a little more doable than the last one. Mocked up with the electronics, we're still a little tail heavy, but not as much as the first version.

 

[Yusernaym]

I'm hoping the increased area will help with the twist, and I'm planning on scaling up the vertical stabilizer (big enough to acommodate a rudder, Mr Stripes) though I'll start with 3-channel for development purposes.

 

[Yusernaym]

I'm hoping the increased area will help with the twist

I'm actually going to make it a twin prop plane, with one at the front and one at the back. It'll help with the twisting and balance, adding some useful weight to the front, and more speed is a win to me.

 

[Yusernaym]

 

[Yusernaym]

the second revision is ready to test, as soon as we stop having ridiculous amounts of wind. I'm really happy with how it looks, and I've upgraded both the servos and control horns for more reliable response. I still haven't spent anything on this build, just pulling parts from planes I don't use anymore, though that'll change when I go get a set of matching props