Mike James

Hi everybody,

Revised from my earlier design, I've gotten some really good aerodynamic advice, and settled on a new planform for my sport jet. I'm in the CAD stages now, and will fly this in spring of 2004. If it works as well as I hope, then I'll make some "short kits" (molded fuselage and foam cores) available. It's designed to use a .60 engine, but I'm sure some of you will add more power.

The airframe is a combination of fuselage attributes from the F-22 and F-35, with wing/tail being a modified version of the Mig 29. In the interest of reducing drag, the jet intakes will be faked graphically. Small NACA scoops at the rear of the fuselage will direct cooling air to the engine. It will allow for retracts, flaps, and (on my version, at least) leading edge flaps. I'm really liking the way it looks, and am now refining the leading edge extensions. Specs are not frozen yet, but approximate dimensions will be 60 inch length and 44 inches span. It's designed to handle up to a 11" prop, and still be able to rotate to at least 10 degrees.

If you want to follow along with the project, it's on my site at http://www.nextcraft.com/j47_sportjet01.html I'll probably post occasional updates here too.

SunShyne

My Feedback: (68)

very nice, look forward to hearing updates on your progress.

Razor-RCU

My Feedback: (50)

I sure liked the single vertical fin better but that jet looks awesome!

I sense Spring-Airs and a Jett-90 might be the ticket!

Cheers!

Strykaas

Mike,

I think an integrated tuned pipe would be great (instead of this ugly muffler). The fuselage seems huge, so it should be easy ... What do u think ?

Mike James

One of the reasons for the twin fins is to disguise the engine.

Yes, a tuned pipe could be concealed inside. I did this on another plane, (the original "Eliminator") with a tractor prop) and had the exhaust exiting through the (doorless) main gear bays. (See image) There's actually more room in this plane, since the fuselage is wider at the rear, so it would be easy to put one there.

Rudeboy

I like it... I like it better than the initial designs...

Any idea of the expected price of the short kit yet...?

By the way... what would you think about a little Wren turbine in the back of that plane....

Mike James

Too soon for me to think about that now, since I haven't done the engineering, but I'm not looking to make millions from this design, so whatever it is, it will be reasonable.

Strykaas

Great !

Mike James

After a little thinking, I've enlarged the scale slightly, (still for .60-size power) to provide a lower wing loading, totally concealed engine, and a more scale landing gear look. Approximate specs now are 68 inch length, 50 inch span.

Strykaas

Mike,

Will u ever ship your future kits to interested builders abroad (e.g. in France) ?

Do u intend making it available as a plan ?

Thanks.

Mike James

This plane will have a molded fuselage, with sheeted foam wings and tail surfaces, so I doubt that I'll have plans available. But I'd be happy to ship anywhere, as long as whoever wants one will pay the shipping. The specific goal of the project is to put a cool looking jet in the hands of people who are not into ducted fans and turbines, so the kit won't be super expensive. To be clear, this is a winter project for me, and so it won't be available until summer of 2004. (early summer, hopefully)

I've gotten some excellent input on this one from some people who know a lot more about aerodynamics than I do, so I'm convinced that it will be a good flying model.

Strykaas

Sure, I would pay for the shipping fees.

So keep us posted about your progress !

lear31A

My Feedback: (123)

What about all the other planes that you have asked about? Where are they? Lets see, there was a B200 king air, starship, possibly? When are you going to start selling those kits? Are you finished with any of them and are they in production? I would love to see a web site to pic and choose.

Mike James

All the projects I'm working on, with constant updates, have been, and still are, on my web site. Last year's mess with a certain manufacturer (don't get me started) held me up for nearly a year, and that's why those projects aren't already finished. (I'm not working on a Starship... You might be thinking of the Piaggio "Avanti".)

I'm working on all of them, and will finish them as I can afford to. ( http://www.nextcraft.com/rcindex.html )

About "kits"...
I'm not a manufacturer. I'm a designer. So, until a manufacturer decides to adopt my designs, (and that was the plan with last year's mess) I design and build them, but do not make a living from sales. I pay for them myself, and I pay for my web site myself. That's why it's strictly non-commercial and free to you... No popups, no banners, no ads, etc..) When they're finished, I can make a limited number of kits available, but I'm not personally equipped for mass production.

lear31A

My Feedback: (123)

Really nice ideas,etc. It seems you are very talented. It amazes me that no one has touched the market with a line of business aircraft ARF's or kits like your working on! I can only imagine when the day comes that a manufacturer produces these. It will open a whole new world for RC. Nothing againt a big stick or those types, but why spend the time and money on something that doesnt even look like an airplane? You can strap a wing on a beer can and fly it, but,... well that actually does sound fun! Anyway, I would be interested in an investment like your talent.

Mike James

Thank you very much. Since I'm obviously not making money doing these things, it's those kinds of comments that help keep me motivated, and convinced that I'm not (completely) insane.

I think that if you start modeling young and keep doing it, you sort of naturally want to search for different projects as you get older. How many "bla bla" planes can anyone build, before they want to build or fly something really different? And, not to be too corny, but it's true that I've had a great time communicating with modelers here on RCU and all over the world, which is the natural result of having a web site. By openly sharing information, we all learn how to do things better.

Take care, and happy flying.

Mike James

Ok...

After a LOT of research, and some very good aerodynamic advice, I've finalized the design, and am starting the actual drawings of the "Eliminator 2" sport jet. Here's some info:

• .60-size 2-cycle, completely concealed (NACA inlets near the tail will cool the engine)

• "Jet intakes" on sides of fuselage are faked graphically, to reduce drag. (The fuselage is a smooth curve)

• Landing gear (retracts) allow for at least a 10 degree rotation on the ground without a prop strike (12-inch prop)

• Separate flaps and ailerons - optional leading edge flaps (Rudders can be mixed inward for pitch & outward for speedbrake)

• Sharp "chines" on fuselage side hopefully create inward-rotating vortexes at high AOA. These, combined with extended dorsal fins on the vertical stabs, and lower F-16 style ventrals, improve directional stability.

• Elevator control is via full-flying stabs, which can be mixed as tailerons.

• Length approx. 69 inches Span approximately 50 inches. (close to 800 sq. in. area, for a low wing loading even at the expected maximum weight of 9 pounds)

I'll post occasional updates here, when I start building it, and updates can also be found at http://www.nextcraft.com/j47_sportjet01.html

Strykaas

Hi Mike !

What's this ?

Better looking, but more complex, and require heavy duty axles and bearings, no ?

Why not an anti prop strike retractable mechanism ? We know some pilots disregard Vmu ...

Strykaas

I've checked your pix on your web site and it seems that the wing is too small. Vertical fins appear nearly as large as the wing ! Do u have any three view to make it clear ?

What's the buzz we hear on your web site ?

Mike James

Hello Strykaas,


1. NACA inlets are a flush-mounted, highly efficient way of getting air into places where you need it. (image attached) See http://www.google.com/search?hl=en&l...et&sa=N&tab=iw

2. I want full-flying, large stabilizers on this design, to improve low speed, high AOA characteristics.

3. There is a recessed area at the fuselage rear center, to allow for a retractable or fixed landing skid for those who want to use one.

4. The wing size issue you mentioned is an illusion, based on the camera type and position, in the renderings I've posted. The wing and tail proportions are more "normal" than they look, but the fuselage is wider. That's to keep the wetted area low for high speed forward flight, but provide more lifting area at low speed, high AOA.

5. I won't be publishing accurate 3-views until the model is released as a kit. I've learned that people simply copy your work when you do that, and now I skew all the images on my web site, to prevent theft.

6. The "buzz" you refer to is a short sound clip from an old American TV show called "The Jetsons", and is only on the page for a little humor.

This will fly in spring/summer of 2004.

Strykaas

thx for your reply.

Had to be a visual effect , yes, due to camera position...

Not a bad idea not to post 3 views, some poeple may copy your work[>:], given that this concept is unusual.

Have u finalized the design ? Are u going to build molds directly or rather make a balsa prototype to be sure there's no issue with the design (IMHO suprises, due to low Reynolds number, are still possible) ?

Mike James

The design is final.

As I mentioned, a LOT of research was done with airfoils, vortex formation, and all the usual moment arm, CG issues, and that, combined with my previous experience, tells me that it will fly well. My personal version will also incorporate leading edge flaps, coupled to the trailing edge flaps, as on actual fighters.

The fuselage will be molded in 3 pieces, (main fuselage, canopy hatch, and rear cowling) and the flying parts (wings and tail parts) will be sheeted foam. I'll also provide molded gear doors, and a molded access hatch for the fuselage top center.

Strykaas

You mean you've had access to a wind tunnel ? Vortex formation is rather difficult to evaluate...

Mike James

I don't have access to a wind tunnel, nor the money to support that kind of research. So, I have "vortex data" (mostly from CFD "fluid flow" studies) but do not have particular information about exactly how it will work on my design. Airfoil data, based on the airspeed I expect, was easy to come up with, and I'm confident, based on my previous sport jet design, that the leading edge flaps will improve low speed performance.

I'm lucky to have several friends here on RCU and elsewhere whom I trust and consult with. Some of them have actually worked on the leading edge flap and lex design on the actual jets such as the F-18, and are able to give me input on these effects at model Reynolds numbers.

There is some guesswork involved in this kind of vortex generation, and I don't pretend to know the minute effects of what I'm doing with this design. But... I also know that this single issue of "vortex generation" will not make or break the model's performance, so I'm making the best educated guess I can, and building a fun model in the process. It's "science experiments" such as this that keep me interested in the hobby. I always learn something in the process.

Strykaas

100% agree

I've already thought about slats, but i haven't been able to figure out how to implement a simple model design, aerodynamically efficient not to disturb nominal wing profile when not extended, and light ... Have u ever tried this on any model aiframe ? IMHO, slats on model aircraft must be really really well designed to be worth it... Even worse when the model gets smaller...
What kind of slats are u going to use ?

I'll stay tuned, this is an interesting project !