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Old Dec 31, 2012, 11:12 AM
http://www.flitemetal.com
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Documentation Supported Diflection Incidence

Yo Tom...best things are often hidden under rocks and overlooked... This is the exhaust incidence shown on the model color
index.... I just drew datum lines to show where the elbow needs to be straightened out to align straight duct between inlet lip
and exhaust outlet...

Note straightened duct is white...at an angle. You need to compare image with the wing incidence datum line to determine the
incidence. I created this in a borrowed computer while on vacation trip and do not have access to normal editing programs
to complete this. Hope this helped....
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Last edited by FliteMetal; Dec 31, 2012 at 11:37 AM. Reason: Edited Image
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Old Dec 31, 2012, 03:34 PM
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Wasted all day yesterday painting that stupid flite metal'd P-51's insignia's and stuff with Dope (which i told the guy wouldn't stick to the the flite metal, but he said use it anyways)... so 8 1/2 hours later when it was time to pull the paint masks off.... the paint came with them! [:@][:@][:@][:@][:@][:@][:@][:@] )#(*$#)(*@$(*)@($*)#@(*$#)(*$#)(*$)($ [:@][:@][:@][:@][:@][:@][:@][:@]


In between coats of paint drying, i did a little to the Horten. First i did some flite metaling on the top of it..

First up was the exhaust indentations and outlining the stainless skinned area with 2 layers of masking tape:


The the stainless skinned area and some hatch's were done:



And then today, i got started on the gear doors.

First and so far the only ones done are the inner main gear doors. I figured these would be a night-mare to do, but they actually turned out to be extremely easy.

I made up a hinge support structure to span the gap between the front and rear edge of the gear openings. It is all 1/8" lite-ply and the 2 pieces going perpendicular to it are cut so the entire thing "keys" together. The rear side is the one with the rectangular shape. I chose this shape so it could be used as a air cylinder mount as well if necessary.. but i've got a nifty idea to make these doors mechanically open and close Simplicity is the name of the game for this airplane, its complicated enough:



Then It was glued into position. I also made up some 1/2" x 1" .030" G-10 door stops. The stops are position where the inner gear door and the lower strut door joints are..



Then a pair of 1/4 scale size pinned hinges were cut in half. The inner gear doors then had the inner layer of glass and about 1/2 of the soric material ground out with a rotary file and the door notched for the Pin edge of the hinge. Then the hinges were epoxied into place. in order to make sure the hinge line was parallel from the front to rear, i move the hinges to a 90* angle and then hang them over the table edge and push the flap against the edge of the table..


Then the doors are placed into position and the hole in the center of the hinges transferred to the ply cross brace. The holes were then drilled out for a 4-40 bolt. Then a Bolt was placed through the hinges on one door, through the ply cross-brace, then through the other doors hinges and then a lock-nut put in place to bolt both doors to the cross-brace. This makes the doors easily removable for maintenance.





The inlet lips and leading edges were also all filled and sanded to shape. I can start flite-metaling the engine cowling now... well, once all the gear door stuff is done so it doesn't have to keep getting flipped up-side down.


Then I stuck the whole-thing together again so I could fill the few gaps between the center section and outer wing panels with body filler:




I also did an initial balance. With the gear down, and 2- 6s 5000mah lipo's as far forward as they can go, the balance point is around 5 1/2" aft of where it needs to be.. not to bad, considering there are no fan units or anything else in the model.

I have already decided that if the airplane needs nose-weight, it will be added in the form of more battery. So it will either fly as a 6s 5,000 6s 10,000 or 12s 5000 Depending on how much weight is needed to get it to balance.
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Old Dec 31, 2012, 03:46 PM
Current project: Electrolyte
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Its alive! Kudos to you Invert. Your one heck of a modeler!
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Old Dec 31, 2012, 03:47 PM
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Thanks man! now to get the 2nd one up and running and we'll be cooking with gas.. lol
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Old Jan 01, 2013, 07:23 AM
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I just saw the discussion of thrust line.

The thrust line should be in line with the wing, that should be around 6 degree angle of attack in case of the wing. In other words, when the center section is 6 degree up with the nose, the thrust line is horizontal.

Heiner
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Old Jan 01, 2013, 08:19 AM
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Angle Of Attack Excess

[QUOTE=heiner;23677311]I just saw the discussion of thrust line. The thrust line should be in line with the wing,
that should be around 6 degree angle of attack in case of the wing. In other words, when the center section is 6
degree up with the nose, the thrust line is horizontal. Heiner[/QUOTE


Heiner,

My illustration expressed the thrust line deflection angle. Thomas has to be careful or he will design in too much
or too little parasitic drag due to thrust line that places it at a "neutral" position.

Historical (hysterical) results serve to disclose a need to load the airframe aerodynamically. This stabilizes the
directional control and permits control surfaces to function...be it at a minimum to cause an effect.

To maintain a load, the mean centerline is positive with the thrust line being negative. The consequence of this
design is excessive energy consumption as shown in everyone's flight videos going all the way back to Gary Heathcott.
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Old Jan 01, 2013, 08:52 AM
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Well the thrust line is pretty well designes in at this point.

With the 90mm fans, a pair of HET or Wemotec inlet rings can be modified (turned down in OD) so they fit snugly into the inlet openings of the wing. This centers the fan with the inlet. With the ply jig i made, the center of the exhaust opening is located. Then with the wing tube and socket attached to the motor of the fan unit and then through the hole in the center of the exhaust opening, the thrust line is built into the airplane.

For those going EDF, i may have it as an option for me to do this work already (inlet ring installation and fan unit mounting, but we will get to that point after this thing flies.

I leave for work on the 8th and will either be back on the 18th or the 25th, so while im gone my buddy Tom is going to try and get caught up with his outer wing panels. Then when i get back, he leaves for a week. So while he is gone, im going to get another center section ready to be infused since he already has all the internal parts ready for the 2nd one.

So, all said and done, we should have two of these things molded up and getting closer to completion by the 15th of Feb.

We may go ahead and mold a 3rd and 4th in Feb. as well
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Old Jan 01, 2013, 09:55 AM
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I can add a little to the thrust line debate. On my Horten I had a slightly non scale outlet position that is oval this allows me to have the exhaust to vary by 2 degrees simply by moving the position at the outlet. I found that a straight line between the engines and the scale outlet was between 4 and 5 degrees to the centre line of the root. I started at 6 degrees up angle and as it worked fine I left it at that position. I guess it would have worked as well at 4 degrees. There are 2 worries about there not being enough up angle is that at takeoff the pitch down effect could be enough to make it a problem to rotate. Also the other thing to worry about is pitch down when applying throttle when in flight. This is less of a problem as it can be neutralised by making a elevator mix. The Horten 229 has the wheels quite far back and the plane needs to 'lift off' rather than rotate about the U/C. It needs full up elevator to be held on takeoff and the plane will lift off and does not jump.

I had just these same concerns on the Schapel Horten type plane I am making at the moment. I have about 5 degrees up angle on the wheels and a similar amount of up angle. on thrust. On this plane it has only been made as a model and the turbine models flying have a rotate problem as they had a small down angle on thrust line.
You can see from this photo how I ended up.

John
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Old Jan 01, 2013, 10:37 AM
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Seems to be a nice big P.111 in the background :-)
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Old Jan 01, 2013, 11:02 AM
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Man you guys are making my head hurt! Its to early in the new year to be thinking this hard. Lol
But from the jist if it all, it seems my thrust line seems about right
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Old Jan 01, 2013, 12:02 PM
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Thomas

Yes go for it!

John
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Old Jan 01, 2013, 12:06 PM
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Quote:
Originally Posted by Balsastaub View Post
Seems to be a nice big P.111 in the background :-)
Yes it is 1:4.22 scale moulded 2m wingspan Kingtech 170 power.

For photos see

http://www.rcuniverse.com/forum/m_11...m.htm#11098219
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Old Jan 01, 2013, 09:08 PM
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Progress... slowly!

Today's progress included gear doors.. more gear doors and boy was it fun!

First up, was cutting the nose gear door into its separate halves. Then some G-10 stop strips were placed at the front and aft edges of the doors and the door's hinged. The hinges were then epoxied and screwed to the center section. Surprisingly, it only took about an hour to hinge both doors, it went fairly quickly and easily.



Then the upper strut doors were hinged. The upper strut doors are a separate molding and uses conventional robart hinge points (the smallest ones) for its hinges. All of the doors except the nose gear doors use conventional hinges for simplicity (not by design, by luck! LOL). So, 2 holes were drilled into the core material of the door for the hinge so where the opening for the hinges fit flush up against the edge of the door. Then the center section was notched for the hinge and a hole drilled vertically down through the edge of the gear plate for the hinges to fit into. Then the entire thing epoxied together. Again, this was the most simplistic way of doing the doors and it just worked out perfectly and completely by luck (who am I kidding, it was all skill! haha)..


And a picture of it on the gear with the doors all attached (except the lower strut doors):


All the doors are now hinged. All that is left, is determining the opening/closing method for the big nose gear door and doing the lower strut doors, which are going to require some head scratching..

We also discovered that our nose gear setup is definitely not going to work, so we have to find an alternative..
AND
the airplane weights around 20lbs right now as airframe, landing gear and two 6s 5000 mah lipo's.

We also assembled the other 2 fan units that Tom got and put a pair of fans into my model:



Then we did a run-up to check the thrust of the motors. It appears that we will be upgrading our power system sooner than we expected. With the expected weight of 30lbs (We expect to need another pair of 6s 5000mah lipo's to use as useable "ballast" to get the airplane to the balance point) and only 12lbs of thrust with the current power package, that is only a .4:1 thrust/weight ratio. While I think it will fly at this, performance will probably be lack luster. Unless you guys think differently? Either way, i'll be saving up for some JetFan 90's on 12S which will give us around 20lbs of thrust.

You can see in this video how crap the nose leg is once the weight of the fans and a batteries is installed.. now just imagine another 5lbs of batteries... the nose would be sitting on the ground! lol

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Old Jan 02, 2013, 03:12 AM
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Thomas

I have a very stiff Behotec nose leg that I adapted, so I did not have problems. However the weight on the nose leg can be a lot especially when I deployed the shortened leg. I had to add about 1.5 Kg nose weight to mine but I did not have any batteries to use.

My thrust to weight is 8 Kg thrust for 18 Kg weight. Takeoff has never been a problem. Heiners ratio was similar and he spent much of his flying just gliding. It is a very slippery airframe and does not need a lot of power, dont forget it was developed from a glider.

John
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Old Jan 02, 2013, 06:01 PM
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the same was seen on models of the Vulcan bomber too. it could fly on little power and was flown mostly gliding. i think you'll be ok on .4:1, but I'd like to see a bit more, just in case.
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