New project: Prop-powered sport "jet"
 

Hi everybody,

Excuse the long-winded post here, but it's by way of background and introduction.

I did a sort of "poll" thread here a while back, asking "Who wants a scale, pusher-prop powered jet?" and got an impressive variety of responses. (Years ago, I did a sport jet that looked cool, but didn't have what it needed, design-wise, to fly great. It was called the "Eliminator". See http://www.nextcraft.com/eliminator.html )

This year, I took a serious look at drawings of the aircraft mentioned in my earlier thread, along with some of my favorites, such as the (X-32 and F-35) Joint Strike Fighters. Keeping in mind that I wanted something fast and nimble, but not "scary", I came up with these answers...

The planes with the long skinny noses, like F-16's tend to be nose heavy models, unless the wings are moved forward, which I think screws up the appearance.

Delta-ish planforms, like the Rafale (which I love) and the F-15 work, but their attribute (like the actual aircraft) is that they are draggy and loose a lot of energy in turns.

Pusher-powered planes work, but they tend to have cooling problems, and pusher props in the size we need are sometimes tricky to find in a hurry. They also have trouble on take-off and landing, with prop strikes. Since I intend to use flaps, and possibly movable leading edge flaps, high angle of attack matters to me, so I put the pusher concept aside.

Finally, since I hate copying other people's work in general, and because this couldn't possibly be as scale as a serious turbine or ducted fan, I decided to come up with something new instead. So...

I'm looking at two versions of the same plane... One with twin vertical fins, and one with an F-16-ish single fin. It will be powered by a 2-stroke .60, and will definitely have slotted flaps. I'm re-exploring leading edge flaps, in an effort to come up with a way to do them that's not difficult to build. I've done them before, in the Larry Wolfe/Jet Hangar Hobbies style, but it was a pain. (Maybe molding the parts will make it easier for more of us to experiment with them.)

So, in the next couple of CAD images, you can see where the "Eliminator 2" stands at this moment. Latest updates will be at http://www.nextcraft.com/j47_sportjet01.html

(One note.. I intend to modify the canopy profile to a slimmer, more "fighter-ish" shape.)

Another image
 

And here's the single-tail version

Lookin' good!
 

Looks like a cross between an 80's Pattern plane (Curare, Tiporare etc.) and a GP Patriot- And that is quite a compliment!

I love the single fin version, cleaner look, and better hesitation rolls :D

You make it, I buy it!
james

New project: Prop-powered sport "jet"
 

it looks interesting, but it really needs at least fake inlets on the side of the fuse to truly look "jetish" ;)

New project: Prop-powered sport "jet"
 

Thanks, James.

Jeremy,

You're right about a jet needing inlets.

I'm not trying to beat a world speed record, but...

To avoid adding structure, (weight) and drag, I may do inlets graphically, rather than structurally, because I would like for this to be as fast as is practical with a stock engine and prop. Even small fake inlets, such as those on F-5 type models, add both weight and drag.

"Slick" is the design goal for me on this one. (It'll be molded glass)

New project: Prop-powered sport "jet"
 

On one of my patriots, I wanted to go faster, so I actually cut the inlets out and built a thin duct that lead to the tailpipe exit, I really don't think it made a hill of beans difference to be honest. But you could always do that, leave the face of the inlet open out to the tailpipe, it did make a neat whistling sound on my patriot LOL. I think if you just made an inlet that stuck out like 3/4", and had the face of it slope back, you could achieve that inlet look and keep it aerodynamic and not increase the drag enough to notice. It looks like you have a pretty wide fuse shape there to start with which will be a little draggy anyway. Either way, I enjoy seeing peoples own creations, it's good to see that in a world dominated by ARF's, there are still designers and builders out there :D

New project: Prop-powered sport "jet"
 

Here's what I did on my Kangaroo (still working on) to reduce drag :)

http://www.rcuniverse.com/gallery/da...o_fuse-med.jpg

pusher
 

Nice work Jeremey

New project: Prop-powered sport "jet"
 

Jeremy, you should have just bought a rookie.

New project: Prop-powered sport "jet"
 

I could have, but the Roo is something more mine now :) plus, I got a great deal on the Roo. I'm also a tinkerer by nature and doing the mods on the Roo is personal satisfaction :)

A little more refinement
 

I've worked on the canopy shape, slimmed the fuselage a little, and rounded the tailcone area, to better support the structure.

Still undecided about whether to add fake inlets or not. We'll see, later.

New project: Prop-powered sport "jet"
 

kind of reminds me of a Ultra Sport with v-tail.. bet it will track nicely