KRS2 Design Study

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Royal

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Just messing around with Fusion 360 and the KR2S. Since I have ADHD I wont be able to ever have a full pilots license. I just want to be able to have a really nice looking airplane based on something that already works. Not that this would ever get built but if someone wants the files let me know.
 

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Chris Matheny

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I'm in the process of starting my KR2S+. Is this and aerodynamic improvement or just for looks? I'll be running an efficient water cooled modern engine and I'm looking for all the efficiency I can get.
 

Royal

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I'm in the process of starting my KR2S+. Is this and aerodynamic improvement or just for looks? I'll be running an efficient water cooled modern engine and I'm looking for all the efficiency I can get.
It would definitely help in the aero. It's very curvy so it would require some molds or something. The canopy could be integrated into the regular kit I think. Im sure you have seen the dragonfly canopy on one.
 

Royal

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I have seen the saberwing. Looks really nice. I don't think I can do the tail dragger since I'm only be able to get a LSA licence.
 

BJC

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I have seen the saberwing. Looks really nice. I don't think I can do the tail dragger since I'm only be able to get a LSA licence.
I’m missing something. What is the correlation between a Light Sport pilot certificate and a taildragger?

Edit: But the Saberwing greatly exceeds LSA speed criteria.


BJC
 

Royal

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I’m missing something. What is the correlation between a Light Sport pilot certificate and a taildragger?

Edit: But the Saberwing greatly exceeds LSA speed criteria.


BJC
Yeah its just an endorsement. I was wrong.
 

Riggerrob

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Dragonfly canopy is better because it more "square" when viewed from the front allowing more room for pilots' collosal egos ... er .. big heads.

In Switzerland, I saw a tiny tail-dragger based upon a KR2. It had an even longer aft fuselage and carried two full-sized men on day trips. It also had a tailwheel.
 

Riggerrob

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Be cautious about adding too many curves to the aft fuselage, especially where the aft fuselage meets wing roots. There are two distinct schools of thought on how to handle airflow around wing roots.
The first school involves oval fuselage bulkheads and large, complex wing root fairings to smooth airflow (ala. Spitfire and Lancair).
The second school of thought says to build simple, rectangular bulkheads (ala. Skyraider and Glasair). Square lower corners require 1/10 the calculations to achieve smooth airflow. Hint! Hint!
 

Royal

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I actually found this out when I was trying to model the fairings from the wings. I can definitely say that if its hard to model its going to be hard to going to be hard to make the air do what you want. I ended up cutting the lower fuselage off midway and brought the fuselage straight down to meet the wing an then have a simple filet to the wing and then a flat upcut tail. What i wanted to achieve was getting the side profile smaller so in a crosswind landing it isn't a B to land. I research a bunch of issues with airplanes then came across a video that a plane was designed around all those issues. I need to find it. It was really good. I dont have a picture of it here at work plus I deleted that work to redo it better. Ill see if i can get some of it done and then send a link to the viewable 3d model.

I also made the canopy more square where the passenger sits. Brought the front edge forward more to reduce some of the drag. I need it to be a bit sharper in the middle. This plane is so small I think you could mold the body in 3 parts and ship the whole thing with other parts inside it.
 

Royal

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Here is the 3d viewable model. Tear it apart engineers.
 

Lendo

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Royal,
Having looked at the KR2 and the KR2S, as well as having the Vision plans, I assume the KR2S and the Vision are similar but with different building techniques, what I would suggest is that all Control Surface Areas be checked against Industry standards and Roncz's papers may go a long way helping in this area.

Now in the situation of designing Wing Fillets, it is generally suggested that you don't reduce the diameter of the Fuselage until a little way past the Wing Trailing Edge, for me this makes sense considering all the conflicting pressures in this area. Just remember Interference Drag is just Pressure Drag.
George
 

BJC

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Here is the 3d viewable model. Tear it apart engineers.
I would add horizontal stabilizers and elevators.

Ditto what Lendo said about the fuselage.

Are you planning to build, or just doing a design study?


BJC
 

Chris Matheny

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Here is the 3d viewable model. Tear it apart engineers.
It doesn't open a model, rather, it just takes you to the download page for fusion. At least on my Android phone. I'll check on my computer.
 

Royal

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I would add horizontal stabilizers and elevators.

Ditto what Lendo said about the fuselage.

Are you planning to build, or just doing a design study?


BJC
Nah. Nobody needs directional stability. lol. JK man. I haven't finished it yet. I haven't planned on changing much of the control surfaces. Although I could if get some help before I start them.
Royal,
Having looked at the KR2 and the KR2S, as well as having the Vision plans, I assume the KR2S and the Vision are similar but with different building techniques, what I would suggest is that all Control Surface Areas be checked against Industry standards and Roncz's papers may go a long way helping in this area.

Now in the situation of designing Wing Fillets, it is generally suggested that you don't reduce the diameter of the Fuselage until a little way past the Wing Trailing Edge, for me this makes sense considering all the conflicting pressures in this area. Just remember Interference Drag is just Pressure Drag.
George
I'll check out those two areas. Since the wings are short and to be folded I think adding the wingtip filets would help or just cutting them back a bit would be easier for building sake.

NOTE: the wing I have isnt correct on this model. The airfoil is a random I drew fast just to give the shape of the wing. If someone wants to build this I will need the middle portion of the wing to draw to scale. This could be built if you want.

As far as viewing the model on a phone you will need to download the fusion app in the store. You can make it up and add notes once you do.
 

Chris Matheny

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Sorry, it worked this time. I really need to learn this type of stuff and might be a little faster than figuring and programming my CNC by hand. Anyone in Ohio want to teach me?
That looks good but sometimes compound angles aren't worth the squeeze. Look at the Whittman Tailwind. Still one of the most efficient planes that the cafe foundation has tested to date.
 
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