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Old May 03, 2011, 05:27 PM
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BelgiŽ, Vlaams Gewest, Scherpenheuvel-Zichem
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I scaled it up for a 90mm edf, fuse is approximately 1400mm span 1000mm.
exhaust is 85% of 51cm≤ intake 100%.
I also made de fuse a bit lower, it simply looks faster this way.






Of course it still needs a lot of adjustments, but guys is this the direction you want to go?
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Old May 03, 2011, 05:31 PM
EDF Jet Jam 2015 , May 28-31
Kevin Cox's Avatar
St. Louis Intl, Missouri, United States
Joined Jan 1997
6,900 Posts
Quote:
Originally Posted by EJETS-II View Post
Hi Kevin,

Thanx a lot for your agreement!

By the way, do you think we could really agree to a common plane for all scratchbuilding friends within a few weeks, or years ;-)

You can see the same question: What's next, if you could choose? in every forum over the world.

Have you seen an agreement already?

Im afraid, we could either not agree if it should be an "Legend" or a Sport jet.
neither the building method, nor if retracts or no, and even single or multiple fan units.

Hopefully one of us is designing- building and flying his own proposal, and is then a good guy giving us the templates to cut styro.
He also has to show step by step "How to", otherwise i dont think that there could be a model built by several friends here in the forum, sharing their experiences.


And also, are you this KEVIN FOX? BAE-Hawk, F-86, ....Me-163............?

BR, Rainer
Hi Rainer,

As I said the guys are having fun and if one modeler is inspired to start building based on the info here then the thread is successful, in my opinion.

My name is KEVIN COX...I believe that we met at Ejets 2009, if you are the Rainer that I am thinking about.
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Old May 03, 2011, 07:00 PM
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St.Catharines, Ontario
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Dirk, that looks incredible. I'de still like to see what it looks like with the wingtips rounded and also curled upwards a little bit.
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Old May 03, 2011, 07:39 PM
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St.Catharines, Ontario
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boredom

your version looks cool too. if you want that plane to go fast, you have to adjust the sweep of the wings. the aspect ratio as you have it, is too much. it looks very much like a Mig 23 with the wings swept forward. take a look at planes like the BVM Electra or the Spark and you'll see what I'm saying. other than that, it looks awesome.
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Old May 03, 2011, 09:47 PM
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United States, GA, Buford
Joined Nov 2007
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The new wing panel is 95% the length of the old and the rest is self explanatory in the pics.
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Old May 04, 2011, 12:59 AM
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HI

I realy like them both, It will be difficult to choose which one I want to build, maybe both.
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Old May 04, 2011, 01:12 AM
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BelgiŽ, Vlaams Gewest, Scherpenheuvel-Zichem
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Quote:
Originally Posted by LuvEvolution7 View Post
Dirk, that looks incredible. I'de still like to see what it looks like with the wingtips rounded and also curled upwards a little bit.
Your wish is my command


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Old May 04, 2011, 02:40 AM
TeamSiam
Graz
Joined May 2007
350 Posts
@ Kevin Cox

Hi Kevin,

Yes, it's me :-)

BR, Rainer
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Old May 04, 2011, 02:52 AM
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St.Catharines, Ontario
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[QUOTE=Von W;18142382]Your wish is my command QUOTE]

LOL. looks great.
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Old May 04, 2011, 10:30 AM
An itch?. Scratch build.
eflightray's Avatar
South Wales U.K.
Joined Mar 2003
13,785 Posts
I can't remember where I found this picture, but it's interesting. Probably early on during my Ducted Prop phase.
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Old May 04, 2011, 01:40 PM
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Denmark
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Quote"as for the inlet/exhaust is concerned, I think Frank is right in that it should be the same percentage inlet and exhaust. if we're going with 85% FSA exhaust, it should also be an 85% FSA inlet. the problem is, is if we are going to go with an 85% FSA with 2:1 ellipse lip (catchment area), or 85% throat plus lip area. if it were up to me, the throat would be slightly smaller, with total area including the lip catchment area. what are your thoughts on this? " Qoute

Rick. I don't why you want to include the intake lips in the areal, can you explain why. Do you wish verry skarp intake lips or somewhat rounded.

If the canards are inclued in the intake the should be non moving, otherwise you will chance the airflow the the inlet. To me thats a no no.

Boredom. I realy like the sexy lines of you fugelage, but I think I whould make it just a bit slimmer form the mid wing to the end. Just something to think about.

I like this playground
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Old May 04, 2011, 04:58 PM
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St.Catharines, Ontario
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inlet design

yeah, it's a little fat in the rear end. I think it should look more similar to what I drew a page or two ago. I think the easiest way to describe what I'm talking about is to look at airplanes like the Eurofighter, that taper down towards the rear, instead of fat looking like the Mirage.

Frank, the intake lip should be rounded, not sharp. if it's sharp, it's going to affect how air is ingested into the duct. this is where the 2:1 ellipse comes into play. the problem is that the lip will add extra area because of its shape. so the question then becomes...........do you want the area of only the throat, or do you want the combined area of throat and lip to equal 85% FSA. if the throat is equal to 85%, the extra area of the lip will increase the total area to about 90% or more. I'll post a drawing below to show you what I mean. I believe it was initially added by Claus but I've modified it with arrows to show you what I mean. the red line represents 85% throat area and the blue line represents 85% area total catchment, which also includes lip area.

Rich
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Old May 05, 2011, 01:29 PM
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Now I get it sorry. Yes I think it's the way to go, the arel should be calculated by the distance from the mid to mid of the intakelip.

Any thoughts regarding airfoils, I think I will try the one I designed my self, it's perfect of delta wings. http://www.rcgroups.com/forums/showthread.php?t=1408077.

One questions, dose a delta wing need washout?
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Old May 05, 2011, 03:08 PM
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well, there's three ways to go as far as washout.

1) you can add geometric twist to the wing
2) you can increase the thickness of the foil at the tip to provide aerodynamic washout
3) you can change the tip foil altogether to add aerodynamic washout

or you can use a combination of all three. the problem with geometric twist, is that it takes away from inverted performance, where aerodynamic washout does not. so to answer your question, yes it should have some washout, but I would go more towards aerodynamic than geometric washout. as long as you have washout and reflex, a delta will perform flawlessly.

as far as your foil goes, it looks very good. the numbers look good too. it all depends on how fast you want to go. thin is obviously fastest and a high point towards the rear is fast.............think NACA 0006 type foils. the high point is almost at the 50% chord line. those foils are incredibly quick, but lifting quality is poor at low AOA/incidence levels, since they are a symmetrical foil. yours looks to be a good combination of both. have you used this foil before, or is it just on paper at this point? just curious to see how it performed if it's flying on a model.
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Old May 06, 2011, 03:17 PM
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Boredom. I hope you haven't decided not to poste you desing here, I like to see more.
Von.W. It's looking awsome, keep up the good job. realy wich I have your cad skills.
Rich. I wold go or option 2 reg. washout. The airfoil is on paper have not been tested yet, but it's very similar to PW 75 that I use on Project 7.

I agree with you to a piont thin wing less drag. But this is only if you keep the AOA within a very small range. If you want low drag over a lager AOA thin is not the way to go, I posted a NACA006 and my own to compere. At RE 300.000 the drag is the same, at +5 deg. NACA006 is 0.02 mine is 0.01 and at +8 deg. NACA is 0.08 were mine is 0.02. I have implemented some reflex resulting in a low movment coefficient just below zero.
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