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Prop jet project for 2004

Old 12-11-2003, 08:00 PM
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Mike James
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Default Prop jet project for 2004

After a kabillion revisions, and some really great aerodynamic advice from friends, here's the final version of my "Eliminator 2", which will fly in spring of 2004. Excuse the round twirly thing on the back, but turbines are out of my league at this time.

This model really is a bunch of "science experiments" for me. If it works as expected, I'll make some "short kits" (molded fuselage, canopy, hatch, and foam cores) available for summer of 2004. It's designed for .60 2-strokes, (or other engines using a 12" prop) and can rotate to at least 10 degrees on the ground without a prop strike. Assuming that drag is low ("intakes" are faked graphically, with small NACA inlets at the rear for engine cooling) I'd expect about 125 mph is level flight. It will accomodate standard retracts, and include flaps. My personal version will also incorporate leading edge flaps, coupled to the trailing edge flaps. The vertical fin "dorsal" extensions will let me find out if some degree of "flow control" from the chines is possible at model Reynolds numbers and high AOA. The F-16-ish ventrals should improve low speed stability, as well as helping to prevent over-rotation.

Basic specs are 69" length, 50 inch span, and 800 sq. inches of (projected) wing area. That gives a light wing loading if built at or under the expected maximum weight of 9 pounds. We'll see...

If you're interested in following along, (I won't spam you here) updates can be found at http://www.nextcraft.com/j47_sportjet01.html

Here are a few images.
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Old 12-11-2003, 08:31 PM
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seanreit
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Default RE: Prop jet project for 2004

Mike, while it's clear you've got skills in computers and such, my experiance with glow powered airplanes up through gas powered airplanes and turbines tells me that the airplane you describe here will never hit 125 mph with a 40 knot tailwind. pusing 9 lbs with as much drag as I see on that airplane with a 60 size banger is going to be marginally fun to fly at best for guys that would expect high performance out of a glow powered banger jet. Take the Tomahawk for instance, I flew one with a Jett 50 and the drag on it alone kept that airplane from achieving over 80 to 90 (estimated) and it's 6 to 7 pounds wet (at least the one I flew).

Nothing personal, but I don't consider what you're showing there to be anything more than an attempt to get Turbine and Ducted Fan Jet pilots to look at your design and possibly a feeble attempt to get us to interested in your project.

Other than the shape of your airplane (which is an obvious knock off of full scale) what about it is supposed to be compelling to the masses (especially the masses in this forum)? And even so, wouldn't it fit better in another area of RCU related to prop driven airplanes?

Now, if you're gonna go through all the work of fiberglass fuse, foam core this and that and present it in this forum, hell, you might as well market it to us as a possible turbine airframe, but you better havfe the funding to go test fly the thing on your turbine, avionics, retracts etc and not ours.

Again, it's clear you have an incredible skill with computers and animation of design, but it's really not clear what you're trying to accomplish on this forum, where'm I wrong?

Sean
Old 12-11-2003, 08:47 PM
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Mike James
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Default RE: Prop jet project for 2004

I often share my ideas on RCU, and others often share their ideas with me.

Nothing more than that to it. If any moderator thinks my post is out of line, I have no problem with it being removed.
Old 12-11-2003, 09:31 PM
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Kevin Greene
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Default RE: Prop jet project for 2004

Sean,

Did someone feed you nails and tacks for breakfast??? Although I personally would not be interested in this project I can tell you this from following Mike's other projects....Mike is an EXCELLENT source of info concerning composites, mold and plug making!!! If and when Mike ever does decide to build and market a turbine jet kit I'm betting it will be very nice. Right now Mike is designing and building what appeals to him. If you can make some spare change in the process then more power to ya!!! Mike....I sure would like to see you put all of that energy of yours into a scale turbine kit. Make it good enough and people will beat a path to your door to buy it. (Then you won't have to worry about having enough money saved for a turbine!!!![8D]) Personally, I would like for SOMEONE to make an accurate scale fiberglass fuselage of the Ziroli F-9F Panther. It would need to be of AirWorld quality. (The Ziroli Panther is smaller than the AirWorld version) I have heard of SEVERAL guys that would buy one if it was nice and priced right. You could put my name on the list now!!!

Kevin
Old 12-11-2003, 09:45 PM
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Centralrchobbies
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Default RE: Prop jet project for 2004

Not to sure about Seans post but if if you can design your own plane for the fun of it and it flies well thats pretty darn cool in my book. Good luck Mike.
Old 12-11-2003, 10:09 PM
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Johng
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Default RE: Prop jet project for 2004

Sean - Exactly how much drag do you see on that airplane?? I don't see much.
Old 12-12-2003, 01:26 AM
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Default RE: Prop jet project for 2004

Never seen Sean post quite like that.... The Jets forum again showing its' "country-club" style mentality [X(] a little elitist (SP?)

If y'all allow those posts about those crappy Kyosho Jets, & Combat Models foamies then a custom designed prop-jet should be received with welcome arms!

Looks like an impressive prop-jet to me! You go Mike!
Old 12-12-2003, 06:59 AM
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Default RE: Prop jet project for 2004

This is an unusual scratch built prop jet.

IMHO, this deserves respect.

If prop jets are irrelevant to the "jet" section, then let's create a "prop jets" section.
Old 12-12-2003, 07:59 AM
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Vampire
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Default RE: Prop jet project for 2004

Mike:

Having designed and kitted prop and Jet models for the past 25 of my 42 year modeling career I personally like folks who think outside the BOX.

It is evident that you are very gifted in the used of CAD solid modeling.

I do know this, one must pursue his pleasures where he finds them and let all else take it course and I would strongly encourage you to pursue this project to completion, verify your project goals for performance then build upon this experience as this is what makes this sport most exciting for me and keeps my interest level peaked after all these years. Every single model I have designed had something I had learned from a previous project or experience. Some good and some bad.

As for your projected performance of this model, with a .60 2cyc. I don't believe you will achieve the 125 mph on level flight but I do think you will be just below the century mark. Hell, all designers need a target and you have set yours, now go see if you can hit it !

Best of luck and most importantly, push on to completion. Even worse than loosing the project to a crash is the project that was never completed and the TOTAL experience lost.

There a many a scale Jet projects that need to be brought to existence and then to market and you may someday contribute to this worthy task. It surly beats putting out another regurgitation of an already existing design as nearly the same effort could have yielded an airframe on the -not done to date - list !

Mike: do your own thing as it appears that you have the makings of a budding designer.

Go for it.

Best Regards:

Kerry J. Sterner
KJ Scaled Designs
SIMJET of Penn.
[email protected]
Old 12-12-2003, 08:00 AM
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Default RE: Prop jet project for 2004

I for one think you did a great job on this design and would be interested. One of my better flying models is an old EZ Pilot Kit of an F-16. It fly’s with using an OS .25FSR. I read a few bad reviews(after I was flying mine) mostly due to the fuel tank being located on the CG making for a 18” fuel draw, but for some reason mine ran/flew great. It did tend to load up a bit on reduced throttle settings. I think your would be a fine project. Good luck.
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Old 12-12-2003, 02:32 PM
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Daren Savage
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Default RE: Prop jet project for 2004

ORIGINAL: seanreit

Mike, while it's clear you've got skills in computers and such, my experiance with glow powered airplanes up through gas powered airplanes and turbines tells me that the airplane you describe here will never hit 125 mph with a 40 knot tailwind. pusing 9 lbs with as much drag as I see on that airplane with a 60 size banger is going to be marginally fun to fly at best for guys that would expect high performance out of a glow powered banger jet. Take the Tomahawk for instance, I flew one with a Jett 50 and the drag on it alone kept that airplane from achieving over 80 to 90 (estimated) and it's 6 to 7 pounds wet (at least the one I flew).

Nothing personal, but I don't consider what you're showing there to be anything more than an attempt to get Turbine and Ducted Fan Jet pilots to look at your design and possibly a feeble attempt to get us to interested in your project.

Other than the shape of your airplane (which is an obvious knock off of full scale) what about it is supposed to be compelling to the masses (especially the masses in this forum)? And even so, wouldn't it fit better in another area of RCU related to prop driven airplanes?

Now, if you're gonna go through all the work of fiberglass fuse, foam core this and that and present it in this forum, hell, you might as well market it to us as a possible turbine airframe, but you better havfe the funding to go test fly the thing on your turbine, avionics, retracts etc and not ours.

Again, it's clear you have an incredible skill with computers and animation of design, but it's really not clear what you're trying to accomplish on this forum, where'm I wrong?

Sean
Pretty cold there Sean. Would you be more interested if it looked like a 'Roo? I am not sure what you're post is trying to accomplish, but as I was taught, if you can't say anything nice, it's probably better to say nothing.

Daren
Old 12-12-2003, 02:42 PM
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A10FLYR
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Default RE: Prop jet project for 2004

Holy cow Shaun, what gives? That sure doesn't seem like the same person who has been posting on RCU.

Hey Mike, hows the B200 project? When do we get one?
Old 12-12-2003, 03:25 PM
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Steve Collins
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Default RE: Prop jet project for 2004

I am not so sure that this one won't be able to hit the 125mph mark if the right engine is used. I would love to see the performance with a Jett .76(same size and weight as the Jett .65) cranking a lot of prop. If the wings and tail feathers are kept pretty thin and assuming this plane will have full retracts, it just might do it.
Old 12-12-2003, 06:12 PM
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Terry Holston
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Default RE: Prop jet project for 2004

Mike it looks good to me, Proof of conceptplanes are tested on props THEN, after they are proven to work, stuff a turbine in it!!! He!!, send me one and I'll stuff it. (Put a turbine in it)LOL
Old 12-12-2003, 06:35 PM
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ryan d.
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Default RE: Prop jet project for 2004

here's a pic for you, sean.
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Old 12-12-2003, 06:59 PM
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Mike James
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Default RE: Prop jet project for 2004

Hi everybody, and thank you for the kind comments.

Sean's remarks, while rude, don't bother me. I'm a 49-year old musician (and modeler since the 60s) and "I've seen it worse."

First, I should say that this project, along with ALL the projects on my site, are entirely non-commercial. I build these things because I want to, I pay for my web site, write it all myself, and have no sponsors or editors to please. You'll notice that there are no banners, popups, or commercial ads of any kind on my site, and that's why it's free for you. IF I'm able to make some kits available, and IF anyone is interested, great. But that's not my motivation.

Anyway, here's some info for the rest of you, just so you know this wasn't "thrown together" to make nice pictures...

I did my first prop-powered sport jet about 10 years ago, and tried to use scale proportions, similar to an F-16. ( http://www.nextcraft.com/eliminator.html ) There's still a photo of this model on the Fibreglast web site, in the "Modelers" section. ( http://www.fibreglast.com ) With a tractor prop, it was always nose heavy, and I eventually abandoned it. So the first decision I made with this one was to use a pusher prop, enabling me to use scale-like proportions more easily. I've recently done an article on using plastic display models to create cross-sections, ( http://homepage.mac.com/mikejames/pl...c_to_rc01.html ) and have always loved the looks of the F/A-22 anyway, so the fuselage is sort of a cross between the F/A-22 and the F-35.

Fake jet intakes are notoriously high drag, so I made the lower section of the fuselage a long smooth curve, and faked the inlets graphically. Small NACA inlets at the rear allow cooling air for the engine. A target speed of 125 mph was established based on using a prop pitch/RPM nomograph, which of course assumes low drag on the airframe.

I posted a question here about a month ago, regarding the LEX (leading edge extensions) on a Mig 29, which are large and rounded, like a B-1, comparing them to the small, sharp LEX ( or "chines" ) on the F-16, but got no responses. I searched for all the data I could on "flow control", ( NASA "HARV", and various CFD "flow studies" ) because I've been curious as to whether any "flow control" of this kind would work at model sizes and Reynolds numbers. There's a lot of guesswork involved, since I don't have wind tunnel access, but after discussing it with some members here, some of whom worked on the F-18 LEX, I decided to keep the chines small and sharp.

Next, airfoil selection. I posted the data and the question, in the "Aerodynamics" section of RCU, and got several responses that verified what I had researched on the "Jets" forum... The optimum airfoil seems to be a 6% to 8% thick semi-symmetrical section, such as the Selig 6062 or RG 15. The wing planform itself is similar to the Mig 29. It has less area than say, the equivalent F/A-22, but is higher aspect ratio and lower drag at the predicted speeds and Reynolds numbers, and I'm hoping that this will help keep the energy up in turns.

Twin vertical fins were chosen for two reasons. First, they help to conceal any engine parts that might be sticking up. (although I've enlarged the scale enough now to completely enclose a .60-size engine) They also allow some mixing functions, such as pitch input and speed brake, as on the F/A-22. After more discussion of "flow control", it was suggested that the vertical fin's dorsal sections be extended forward to the max thickness point on the wing, to better contain and control whatever vortexes the chines might generate at high AOA. To further aid low speed directional stability, and to help prevent over rotation, F-16-ish ventral fins were added. (very thin... almost no drag in cruise) The ventral fins also give a visual cue for approach, defining the max ground rotation angle (with a 12" prop) of 10 to 11 degrees.

Gear will be retractable, and can be standard Spring Air types, etc.. My personal version will include leading edge flaps, coupled to the trailing edge flaps, as Bob Fiorenze did on one of his F-18s, about 12 years ago. Mine will use an actual pivoting leading edge, like the F/A-22, rather than the "leading edge within another leading edge" type used on some of Larry Wolfe's projects for example. (I did that method on my first sport jet, and the camber change DOES help.) I've just gotten my CAD drawings blown up to the appropriate scale, and will start the actual drawings for the plugs this weekend. Updates on this project will be at http://www.nextcraft.com/j47_sportjet01.html

About the King Air...
YES! I'm sanding it every day, and it's on schedule for flight in summer of 2004. (I'd like to have it ready for contest season, but can't guarantee it.) Thanks to the surface treatment that will be given to it by Paul Reese, this will probably (no, definitely!) be the most accurate and beautiful scale project I've ever done. Paul's work is immaculate. Updates on the 1/6th scale King Air B200 are at http://www.nextcraft.com/b200_construction03.html

Thank you again to those of you who took a look at the "Eliminator 2" jet project, and for your kind support. I don't post very much around here, because I don't fly turbines. But I always read the "Jets" forum, and am familiar with the great work that many of you do. Kerry Sterner's contributions to this hobby have been a source of inspiration to me on more than one occasion, and I know who most of the rest of you are, although you wouldn't necessarily know me. You certainly have my respect, and when I'm qualified to do it, will be doing some turbine projects.

Happy flying!
Old 12-12-2003, 10:04 PM
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jetsetter
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Default RE: Prop jet project for 2004

Mike, I like it. Who pissed in Sean's cheerios?



Larry
Old 12-12-2003, 10:25 PM
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Default RE: Prop jet project for 2004

After going back and carefully re-reading Shaun's post I think he ment it to be more constructive than we are giving him credit for. It's just another example of "If you didn't listen so hard to what I said you would have understood what I ment". Lets give him a break!

Besides, I'll bet it would fly with a 44 or 54 size turbine!!!
Old 12-12-2003, 10:38 PM
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Razor-RCU
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Default RE: Prop jet project for 2004

Nope... I re-read it and Sean is off base and condescending! (And I like Sean )
Old 12-12-2003, 11:02 PM
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Default RE: Prop jet project for 2004

Sean - You need to change your moniker to D-CON. You must have had some for breakfast
Old 12-12-2003, 11:44 PM
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EddieWeeks
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Default RE: Prop jet project for 2004

Mike... My first ducted ever ducted fan did not work to well so you know what I
designed and built..

Prop Jet

You boys may want to give this man some slack...
Looks like he is going to do more than just read directions to build his jets...

Eddie Weeks
http://www.corpcomp.com/weeks1/
Old 12-12-2003, 11:51 PM
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Default RE: Prop jet project for 2004

Sean, ease off the nukes[>:] He is entitled to his post just like the rest of us.

I think it looks great.
Mike, let us know how much for a kit when you reach that point.[8D]
Old 12-13-2003, 12:00 AM
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Daren Savage
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Default RE: Prop jet project for 2004

ORIGINAL: A10FLYR
It's just another example of "If you didn't listen so hard to what I said you would have understood what I ment". Lets give him a break!
Sorry Dean, I don't buy it. How can comments like:

"Nothing personal, but I don't consider what you're showing there to be anything more than an attempt to get Turbine and Ducted Fan Jet pilots to look at your design and possibly a feeble attempt to get us to interested in your project.

Other than the shape of your airplane (which is an obvious knock off of full scale) what about it is supposed to be compelling to the masses (especially the masses in this forum)? And even so, wouldn't it fit better in another area of RCU related to prop driven airplanes?

Now, if you're gonna go through all the work of fiberglass fuse, foam core this and that and present it in this forum, hell, you might as well market it to us as a possible turbine airframe, but you better havfe the funding to go test fly the thing on your turbine, avionics, retracts etc and not ours."


Be construed as constructive?

Perhaps if he's mature enough to come back here and apologize for some of his comments then I can see what you're saying. Otherwise his words speak well enough for themselves.

Like the old saying goes, "If the person you're dining with is nice to you, but rude to the waiter; this is not a nice person."

Dare
Old 12-13-2003, 01:15 AM
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Default RE: Prop jet project for 2004

Mike, ol' buddy ol' pal,
You continue to amaze me as you always do. Pusher schmusher...if you build it they will come. That thing needs some weathering though
Continue on with the awesomeness that is Mike James.

Paul
Old 12-13-2003, 01:24 AM
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Mike James
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Default RE: Prop jet project for 2004

Thanks, Paul! (and others) The feeling is mutual, and you're right about the weathering. Now that the design is finally frozen, I can stop editing texture map shapes, and start to do some of that. (Later, though. I want to get some drawings happening, which I'll have to wait until Monday to do.)

PS> I've become a big Harald Huf fan... Wow. ( http://www.su27projekt.de/ )

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