Fairings at the wing root
07-25-2008, 11:56 PM
#26
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RE: Fairings at the wing root
Perhaps I should have asked this before but only had a vague idea of what I wanted to do.
Will a fairing such as this reduce/increase the amount of effective wingspan or area?
Where it is of such a long cord will that cause issues with the COG location?
I have included some pictures to give you an idea of the finished fairing.
One final question I just thought of.
Is it better to blend the fairing back into the top of the fuselage canopy?
Or should I continue the rounding off of the top of the fuselage into the fairing shape using the large curve that is the top of the canopy hatch?
I am thinking it would be better to continue the airfoil shape onto the canopy hatch, it matches closely the front of the canopy if you can picture a bit of rounding off type of transition.
Edit to add:
When I was asking about the COG location what I meant was do these type of fairings effect the MAC location? And with that I should mention that I am extending the wingtips about an inch and a quarter in span. Partly because I shifted the flaps and ailerons outboard by ¾ of an inch and I needed to enlarge the wingspan by at least that much. Now I know I will have to recalculate the MAC because of that although I suspect the change will not be all that large. I am just curious if the large fairings I a, using count as wing or fuselage…
Will a fairing such as this reduce/increase the amount of effective wingspan or area?
Where it is of such a long cord will that cause issues with the COG location?
I have included some pictures to give you an idea of the finished fairing.
One final question I just thought of.
Is it better to blend the fairing back into the top of the fuselage canopy?
Or should I continue the rounding off of the top of the fuselage into the fairing shape using the large curve that is the top of the canopy hatch?
I am thinking it would be better to continue the airfoil shape onto the canopy hatch, it matches closely the front of the canopy if you can picture a bit of rounding off type of transition.
Edit to add:
When I was asking about the COG location what I meant was do these type of fairings effect the MAC location? And with that I should mention that I am extending the wingtips about an inch and a quarter in span. Partly because I shifted the flaps and ailerons outboard by ¾ of an inch and I needed to enlarge the wingspan by at least that much. Now I know I will have to recalculate the MAC because of that although I suspect the change will not be all that large. I am just curious if the large fairings I a, using count as wing or fuselage…
07-26-2008, 05:33 AM
#27
RE: Fairings at the wing root
The fairings will make no difference to the a/c aerodynamically other than to tidy the airflow a bit around the wing fuselage junction. Adding a bit to the wing tips, provided the extensions follow the taper of the wing, will make no difference to the MAC. So, nothings changed, then.
Evan, WB#12.
Evan, WB#12.
07-26-2008, 06:19 AM
#28
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RE: Fairings at the wing root
You pose an interesting question about the fairings being part of the fuse or the wing. I think they'll be part of the wing because of their airfoil shape, but the lift probably won't be enough to affect the flight characteristics very much. That's just a WAG on my part...
Nice job on blending in that first fairing. Is that the finished fairing or are you going to put in a 'rain gutter'? (i.e., sand the surface concave)?
Bob
Nice job on blending in that first fairing. Is that the finished fairing or are you going to put in a 'rain gutter'? (i.e., sand the surface concave)?
Bob
07-26-2008, 12:32 PM
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RE: Fairings at the wing root
last night as I looked at the fairing on the airplane I really started to think about how such a large fairing would effect the aerodynamics of the airplane and became concerned enough to ask about what these effects might be. Both replies thus far have helped to calm my fears.
I am curious about if they are considered part of the fuselage or a lifting surface. For the moment I am looking at them as being part of the fuselage and proceeding as such.
Bob,
Thanks.
As far as sanding the concave into the fairing, perhaps a bit, but not all that much as pimmnz observed they are intended to tidy up the airflow around the fuselage wing junction. The picture shows the fairing just sitting there it is not blended into anything at this point. As far as blending all I am going to do is add fillets around the fairing where it meets the fuselage and the wing, and call it good. The other part of my question was how to treat the joining are between the widest top part of the fairing and the top of the fuselage on the canopy hatch/canopy front.
I am curious about if they are considered part of the fuselage or a lifting surface. For the moment I am looking at them as being part of the fuselage and proceeding as such.
Bob,
Thanks.
As far as sanding the concave into the fairing, perhaps a bit, but not all that much as pimmnz observed they are intended to tidy up the airflow around the fuselage wing junction. The picture shows the fairing just sitting there it is not blended into anything at this point. As far as blending all I am going to do is add fillets around the fairing where it meets the fuselage and the wing, and call it good. The other part of my question was how to treat the joining are between the widest top part of the fairing and the top of the fuselage on the canopy hatch/canopy front.
07-26-2008, 11:38 PM
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RE: Fairings at the wing root
Sorry to bust your bubble but they aren't all that large. Certainly not enough to need to factor in any changes for wing area or concerns about lifting fuselage area.
With a model that may have aspirations to flying in a 3D mode with harriers and hovering you won't want to use really big fairings anyway. If they are really large it'll move the inner edges of the ailerons out and slightly reduce the ability to use the prop blast for control.
What your present fairings will provide is possibly a cleaner flow over the inner aileron area. I guess time will tell.
With a model that may have aspirations to flying in a 3D mode with harriers and hovering you won't want to use really big fairings anyway. If they are really large it'll move the inner edges of the ailerons out and slightly reduce the ability to use the prop blast for control.
What your present fairings will provide is possibly a cleaner flow over the inner aileron area. I guess time will tell.
07-26-2008, 11:53 PM
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RE: Fairings at the wing root
Thanks Bruce!
Where they are just over 22 inches long and 3/4 of an inch thick I figured that they may be a issue as far as COG or alike.
The neat thing is that they look cool and make a real nice transition from the fuselage to the wing if nothing else. But they do stiffen up the fuselage sides some and weigh in a 0.4 oz each so I am not adding a hole lot of weight with them and I had already chopped out a lot more than that out of the fuselage already.
I am still in a bit of a quandary of how to join the fuselage top hatch to the fairing as far as blending could you see what you think about that. It is about 1/4 of an inch above the base of the canopy hatch and around 2/3 as high as the hatch.
Would it be better to blend the fairing into the fuselage to or the fairing into the fuselage in your opinion.
Where they are just over 22 inches long and 3/4 of an inch thick I figured that they may be a issue as far as COG or alike.
The neat thing is that they look cool and make a real nice transition from the fuselage to the wing if nothing else. But they do stiffen up the fuselage sides some and weigh in a 0.4 oz each so I am not adding a hole lot of weight with them and I had already chopped out a lot more than that out of the fuselage already.
I am still in a bit of a quandary of how to join the fuselage top hatch to the fairing as far as blending could you see what you think about that. It is about 1/4 of an inch above the base of the canopy hatch and around 2/3 as high as the hatch.
Would it be better to blend the fairing into the fuselage to or the fairing into the fuselage in your opinion.
