Scaled Jets (F-16)

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Acrojet, Jun 6, 2016.

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  1. Jun 15, 2016 #161

    DangerZone

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  2. Jun 27, 2016 #162

    Glider

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    A wonderful thing about gliders, especially tandems, is that the forward seat is out in front of the wings. Somewhat jet-fighter like view.

    A wonderful think about the F-16 is that the canopy has no obstructing and distracting frame in front of the pilot. What a perfect view it must provide.

    And isn't the view the whole point of getting in the airplane and doing some aviating (except maybe aerobatics)?

    I also like how the wings of a Pitts frames the forward view, sexy, but obscured.
     
    Last edited: Jun 27, 2016
  3. Jun 27, 2016 #163

    BBerson

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    The A-10 would make a cool scale jet. Could be 50-60% scale. Full scale is 57' span.
    Would work with piston or electric ducted fans also, with the big ducts. It isn't made for speed.
     
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  4. Jul 21, 2016 #164

    Tomcat

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    Best of luck with this endeavor, Peter.
     
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  5. Jul 28, 2016 #165

    metalist93

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  6. Nov 25, 2016 #166

    Acrojet

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    Quick update!

    Sorry for the long delay in posting updates but it's been a long hard look at into why our numbers were so off. Now I know why........
    Had to reassess things and determine the best course of action once it was determined that carbon was lighter than Al as long as it's engineered from the start.

    Pretty excited that we are able to move forward and actually start working on things early next year (2017)

    Meeting with new aeronautical engineers that specialize in composite construction after I determined that going with Carbon fiber (TexTreme) as the material for the F-16 was the best course of action in order to achieve the strength needed and ease of kitting required. We will start the plugs/molds early 2017 and first parts will be pulled from the new molds later in the year. It will be an aggressive work schedule, but we've got some excited workers and involved partners that want to see this come to fruition. Plans are to get it done and flying for Air Venture 2018. That's a tight window, but I'm being told everyone is on board and ready to roll!

    We've switched to the DGEN-390 (740lbt) from Price Induction as our engine choice as the original engine developer has run into funding issues. (That's always the story.....). It's a little heavier than the original design, but it has great fuel specifics, and will be a "plug 'n play" unit.

    We've also increased the scale slightly from 60% to 66% (2/3) to make for a little more room.

    Here's a comparison with an actual full scale F-16 for comparison:
    IMG_1226.jpg

    Happy Thanksgiving!!!

    Peter
     
  7. Nov 26, 2016 #167

    Terrh

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    Why not go with corvette engines and ducted fans? Seems like a good idea to me, and gotta be cheaper to operate/maintain/repair than any "cheap" turbine. I get that it's a weight penalty, but you should be able to hit significantly higher thrust numbers even on just one LS engine.
     
  8. Nov 26, 2016 #168

    Acrojet

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    You know I've looked into that but, unless someone has an "off-the-shelf" ducted fan recip that they'd be willing to give up the technology for, I'm gonna pass on that one. The technology isn't quite there yet to make it "mainstream". As you've stated there's a little weight penalty and I don't think what's out there for ducted fans really has the thrust output that I need at the weight I need it at (thrust to weight ratio). Yes we burn more, so we have to carry more and that weighs more, but jet engines are so much more reliable and silky smooth inoperation that it's hard to beat for what we need/want. Don't get me wrong, if the guys that made the "UL-39" and the "PJ-Dreamer ll" ducted fan aircraft would like to sell them for my aircraft, I'd be willing to listen......

    Peter
     
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  9. Nov 26, 2016 #169

    Terrh

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    He's on this forum, and I think wants to sell more of those aircraft... might be worth a shot asking if he'd sell you an example of the transmission/fan setup. And I can build you the engine (though probably so can a million other people closer to you).
     
  10. Nov 27, 2016 #170

    autoreply

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    I'd stay away from TexTreme. It looks awesome. But it's twice the price of Biax/Triax, heavier and less stiff. For highly compound curved parts, you'd be much better off with traditional plain or satin weave T700 or so.

    In general, be aware of fancy marketing, especially in composites. Lots of people making lots of money selling overhyped services or products. The Arnold videos, Rutan's books and several boat building blogs are great places to start. Same with the Arletty II build blog. Note our composite FAQ that contains dozens of useful links:
    http://www.homebuiltairplanes.com/forums/showthread.php?t=8888

    Given the fairly simple shapes of the F16, I'd consider making a single plug for the entire fuselage and pulling molds off it. Hotwired XPS can be an incredibly cheap and fast way to build such a massive plug. Make sure to first go through the entire process (plug making, mold making, part making) with something smaller, say the H-stabs or so.

    Would a 2-seat version be feasible? IMHO, that'd massively increase future market potential, even if it ended up as a 1.5 seat design.
     
  11. Dec 10, 2016 #171

    pajlotmato

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    Interesting idea. Some time ago I also dealt with the idea of a unique design for some small commercially manufactured jet but not just by reduced scale but with minor modifications to the detriment of the correct scale. I tried design one of my favorite jets F-18 Hornet and it looked something like on picture below. Finally, I came to wingspann 5222,44 mm and length 7480mm, it would be powered by twin small turbine similar to PBS TJ-100. It was just idea but I want to build it in 1/3 scale as RC for some testing...Keep that project alive please, it will be fine observe how it become in real small F-16...

    HBA01.jpg
     
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  12. Dec 10, 2016 #172

    Swampyankee

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    No. To get that kind of sfc, you need a high core pressure ratio, a high turbine inlet temperature, and a high bypass ratio, and suffer from decreasing achievable efficiencies of turbomachinery as size decreases, mostly, but not entirely due to Reynolds' number effects, proportionately greater parasitic losses in bearings, lower combustor efficiencies, and a slough of other problems. If they could produce 700 lbst thrust engines with a tsfc of 0.4 lbm/lbf-hr and sell them for only two or three times the price of a brand-new IO-550 or IO-580, Sesenich and Hartzell would go out of business.
     
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  13. Dec 10, 2016 #173

    Acrojet

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    I was waiting for you to chime in!
    I appreciate your input.
    I will only be using Textreme in certain areas. As you mentioned there are other obvious better choices. We will be using various combinations TexTreme/Innerga and others. Part of what is "driving" the Textreme and Innegra is that they have sponsored the materials for two prototypes for us! We will also be using "infusion" technology by ACI for our parts as well. Things are moving pretty fast, but rest assured these guys know what they're doing. The primary partners have been doing composites for over 35 years and have developed several composite kits over the years. All of the data is computer modeled in CF and reinforced where needed. So there will be certain blends of CF to keep it strong, light, and cost effective. I'm pretty confident at what it will turn out to be. Thanks for the input.
    As far as the plugs and molds goes, this too have been sponsored, so cost for me is a non-issue, at least at this point.
    I will keep you updated as we progress. The plans is to hot wire the wings and tail, vertical and CNC the FU. The FU will be with three parts much like this:

    IMG_1265.jpg

    Yes we plan to make the first one a full two-seat version:

    IMG_1230.jpg

    There will be a provision to go with either canopy versions as the builder desires. All the controls will be there, and the ability to change from one version to the other will be designed into the kit from the start.


    Peter
     
  14. Dec 10, 2016 #174

    Acrojet

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    Very cool!
    I actually have plans (way in the future) to have a family of scale jets for the kitplane market and the "F-18" two-seat version is my next choice! Other candidates could be:
    A-10, A-4, F-86, F-4........

    Peter
     
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  15. Dec 10, 2016 #175

    Swampyankee

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    Warthog would probably the easiest of them: straight wing, lowest loading.
     
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  16. Jan 14, 2017 #176

    DangerZone

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    Hey Peter, great updates and all the best to your project in the new year!

    Is there a picture showing the seating arrangement in the two seat version? The one with the full scale F-16 seems to show enough room only for the pilot...
     
  17. Jan 14, 2017 #177

    Acrojet

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    Sorry about that. That was an earlier rendering and even that pilots placement in the single seat version wasn't exact. It was more to get a "sizing@ comparison. We will have other pics as time goes on. Stay tuned!!
     
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