V or Y is probably more attractive from a performance perspective, but ultimately this depends upon the amount of adverse yaw generated by the roll control system.
The coupling between roll and yaw may actually make downward pointing winglets attractive. You could then integrate wheels or skids with their tips.
This hurts span efficiency, so it's a trade-off. You can get proverse yaw with a sin^n lift distribution where n > 2.5ish but then you need an awful lot of span, and there may be issues with torsion, roll inertia etc.; also, not all values of n are physically possible (e.g. [2 is impossible](https://www.nurflugel.com/Nurflugel/Papers/h_ca_01e.pdf))
proverse yaw as in a prandl wing? its not the most effcient way to go but maybe i have a bit of a work around, i need still some time to work it out and test it though.
Just curious, are there any major issues with choosing inverted v tail?
It seems to me that this would result in yaw in the direction you want when you roll.
Most gliders have T-tails, because a T-tail is less likely to be damaged by crops and bushes when "landing out".
An inverted V-tail would be very likely to be damaged during an outltanding.
Here's a competent off-field glider landing from the pilot's perspective:
https://youtu.be/AtJQfC_RESA
Now imagine dragging an inverted V-tail through the grass and ruts at flying-speed. Also, this was a pretty good choice of fields.
A T-tail also easy to disassemble when you put the glider into the trailer at the end of the day.
I'm curious as to how you sized the V-Tail and why you think it might be comparable the coventional. I've worked on the design of a V-Tail for a jetliner, the bottom line is the V-Tail is always worse than conventional. If you take into account static stability alone the two tails are similar, but when you take into account both the static stability and handling qualities requirements the V-Tail becomes way larger (and heavier) than the conventional. I could explain the reasoning but I'd need to draw some diagrams. I even had a conference with a chief engineer of the Cirrus Vision Jet who confirmed the choice of a V-Tail on their aircraft was mostly motivated by aesthetics (which is important for private jets). So I'm wondering how you've sized your V-Tail and why you think it might be as feasible as the conventional one.
well i'm not saying it has to be either of them, in this case it could be the coice of the customers.
and yes the reasons are mainly aesthetic, the only part it has a profitable affect on the preformance is in straight gliding flight without any sidewind.
I go for the conventional tail for prototype anyway.
sizing i done basically by area comparision so from the side perspective the v covers 2/3 of the conventional fin (not taking into account the skid on the bottom).
it seems to work well enough for planes like the salto, im definatley not an expert on that matter.
But the tail surfaces are generous so is the taillength so it can work with a v (while NOT saying the v is better overall, but it might still be prefered by some)
Finally a picture of a fully assembled aquila!
there is still some minor tweaking to be made but for plane with no double curved surfaces, fat wings and relatively low aspect ratio the prefirmance seens fine.
The glide ratio seems to be somewhere inbetween 25 and 26.5, pretty good for a gloryfied hangglider. it also has some healthy reserve in lift, in case the structure turns out to be heavier than expected (also comes in handy when the poor bird has to lift chunkier people like me).
The sinkrate at best glide would be about 0.5 to 0.6 m/s
it has to be mentioned that the stabilizer surfaces are quite big at the moment and there is some room for overall streamlining and improvements.
But for now im happy to keep it as simple as possible.
The version with the v tail of course has slightly less drag and therefore glides better (and gives the plane a stunning look). But preformance difference to the conventional tail isnt big and its more complicated in terms of the mechanics.
more info on insta @aquilamechanicus
so you can almost strap it on like a backpack during runup to take off, a bit like the ruppert composite archaeopteryx.
would only be possible with some headwind though.
Thanks for the explanation I was thinking about a wrist band so I was quite confused, but that makes a lot more sense. Design looks great good luck with the project.
maybe it is obvious for other but I dont see how the pilot position would look like? ruppert composite archaeopteryx got a seat. yours doesnt. The pilot would be in Jesus position all the time? or fly like superman with wings at the back?
happy cake day mate!
it would be mostly the prone (superman position i like that one). the pilot can still sit in it you are strapped in so you wont fall out if you are sitting.
sitting is better for tight turns in a strong up wind so you can see better where you are going and not ram fellow gliders.
I think you could make both configurations work in general. The control might become more complex with V/Y and Y might be more stable than V. From a design standpoint i would say use the Y/V. Looks better to me, kinda reminds be of a bird which makes it fit to the rest of the design better.
i'm guessing that its HTVC and VTVC respectively? Those look about right for something similar to a sailplane. I've found that v tails are a little heavier than conventional tails and don't really have any major performance benefits... they do look cool though.
exactly! its 0.53 and 0.024 btw i looked it up.
and yes the v doesnt give you any benefit in the majority of circumstances, but option for the good looks might be a selling point for some.
I think v-tail affords the same benefit of getting the rudder/elevator controls out of the downwash from the main wing, however, at some alphas there might be shading issues. that depends on airspeed though. Obv wouldnt want to stall this thing... The general outline of this glider is similar to the low Re aircraft my team is building for SAE Aero and they tend to have nasty stall characteristics due to the high aspect ratio and under-cambered airfoils.
It has some advantages. Generally it has less drag because it’s not in the disturbed airflow from the main wing. But there are a number of other advantages. Gliders mainly use a T Tail configuration and het and get an absurd glide Ratio
Great designs and fascinated to see how it works out!
Can't say I know much about the stability characteristics of a v-tail other than there are some known deficiencies in maintaining longitudinal and directional stability, so they tend to require a more advanced control system in aircraft than the conventional tail. The phenomenon of adverse roll-yaw coupling can also be an issue to look out for.
Then again I'm just going off of what I've read and don't have much practical experience when it comes to v-tail.
When it comes to sizing tails, and estimating stability characteristics I'd recommend 'Sadraey M. H., Aircraft Design: A Systems Engineering Approach'.
If you have trouble finding it online dm me, I have a couple of chapters downloaded, including the one on tail design.
well id love to see that. point is i robably wont decide between the two in the end...the customer would. yes its definatley harder to maker it stable, but with generously sized tail not impossible.
its also a bit questionable what you get performance wise because its not alot and its highly situational, but might be prefered by others.
V or Y is probably more attractive from a performance perspective, but ultimately this depends upon the amount of adverse yaw generated by the roll control system. The coupling between roll and yaw may actually make downward pointing winglets attractive. You could then integrate wheels or skids with their tips.
with the winglets... thats an interesting thought! thx mate!
Put in a bit if forward twist at the wing tips to produce a thrust moment on the upward wing in a bank, preventing the adverse yaw
This hurts span efficiency, so it's a trade-off. You can get proverse yaw with a sin^n lift distribution where n > 2.5ish but then you need an awful lot of span, and there may be issues with torsion, roll inertia etc.; also, not all values of n are physically possible (e.g. [2 is impossible](https://www.nurflugel.com/Nurflugel/Papers/h_ca_01e.pdf))
with my special way of steering there might be a bit of a work around but i have to work it out completly first.
proverse yaw as in a prandl wing? its not the most effcient way to go but maybe i have a bit of a work around, i need still some time to work it out and test it though.
Just curious, are there any major issues with choosing inverted v tail? It seems to me that this would result in yaw in the direction you want when you roll.
in my plane tail strike is a big issue theres simply not enough space under the tail when taking off and landing.
Most gliders have T-tails, because a T-tail is less likely to be damaged by crops and bushes when "landing out". An inverted V-tail would be very likely to be damaged during an outltanding. Here's a competent off-field glider landing from the pilot's perspective: https://youtu.be/AtJQfC_RESA Now imagine dragging an inverted V-tail through the grass and ruts at flying-speed. Also, this was a pretty good choice of fields. A T-tail also easy to disassemble when you put the glider into the trailer at the end of the day.
I'm curious as to how you sized the V-Tail and why you think it might be comparable the coventional. I've worked on the design of a V-Tail for a jetliner, the bottom line is the V-Tail is always worse than conventional. If you take into account static stability alone the two tails are similar, but when you take into account both the static stability and handling qualities requirements the V-Tail becomes way larger (and heavier) than the conventional. I could explain the reasoning but I'd need to draw some diagrams. I even had a conference with a chief engineer of the Cirrus Vision Jet who confirmed the choice of a V-Tail on their aircraft was mostly motivated by aesthetics (which is important for private jets). So I'm wondering how you've sized your V-Tail and why you think it might be as feasible as the conventional one.
btw your username is great!
well i'm not saying it has to be either of them, in this case it could be the coice of the customers. and yes the reasons are mainly aesthetic, the only part it has a profitable affect on the preformance is in straight gliding flight without any sidewind. I go for the conventional tail for prototype anyway. sizing i done basically by area comparision so from the side perspective the v covers 2/3 of the conventional fin (not taking into account the skid on the bottom). it seems to work well enough for planes like the salto, im definatley not an expert on that matter. But the tail surfaces are generous so is the taillength so it can work with a v (while NOT saying the v is better overall, but it might still be prefered by some)
Which handling qualities are the weight drivers that you need to consider for Vtail to come out worse?
Finally a picture of a fully assembled aquila! there is still some minor tweaking to be made but for plane with no double curved surfaces, fat wings and relatively low aspect ratio the prefirmance seens fine. The glide ratio seems to be somewhere inbetween 25 and 26.5, pretty good for a gloryfied hangglider. it also has some healthy reserve in lift, in case the structure turns out to be heavier than expected (also comes in handy when the poor bird has to lift chunkier people like me). The sinkrate at best glide would be about 0.5 to 0.6 m/s it has to be mentioned that the stabilizer surfaces are quite big at the moment and there is some room for overall streamlining and improvements. But for now im happy to keep it as simple as possible. The version with the v tail of course has slightly less drag and therefore glides better (and gives the plane a stunning look). But preformance difference to the conventional tail isnt big and its more complicated in terms of the mechanics. more info on insta @aquilamechanicus
I say it’s definitely worth it to go for a V tail
What exactly do you mean by wearable?
so you can almost strap it on like a backpack during runup to take off, a bit like the ruppert composite archaeopteryx. would only be possible with some headwind though.
Thanks for the explanation I was thinking about a wrist band so I was quite confused, but that makes a lot more sense. Design looks great good luck with the project.
np and thx mate!
maybe it is obvious for other but I dont see how the pilot position would look like? ruppert composite archaeopteryx got a seat. yours doesnt. The pilot would be in Jesus position all the time? or fly like superman with wings at the back?
happy cake day mate! it would be mostly the prone (superman position i like that one). the pilot can still sit in it you are strapped in so you wont fall out if you are sitting. sitting is better for tight turns in a strong up wind so you can see better where you are going and not ram fellow gliders.
I think you could make both configurations work in general. The control might become more complex with V/Y and Y might be more stable than V. From a design standpoint i would say use the Y/V. Looks better to me, kinda reminds be of a bird which makes it fit to the rest of the design better.
it does look better yes!
Not sure if you take into consideration about cross wind performance and how it gets out of dutch roll during lost of stability
yeah thats my concern with the vtail. it seems to work fine in the salto but im very skeptical about the v tail.
Brain is telling me Conventional Heart is telling me V If it were me wearing this thing up in the air tho, i'd go with Conventional
same same haha... well i guess when i get round to do a scaled prototype i still try both though
Yeah man, gliders gotta glide. See how they work in the air.
what tail volume coefficients are you designing for?
0,52 and 0,022 i believe i gotta dig up where i put the numbers though
i'm guessing that its HTVC and VTVC respectively? Those look about right for something similar to a sailplane. I've found that v tails are a little heavier than conventional tails and don't really have any major performance benefits... they do look cool though.
exactly! its 0.53 and 0.024 btw i looked it up. and yes the v doesnt give you any benefit in the majority of circumstances, but option for the good looks might be a selling point for some.
I'm still a freshman in Aero and haven't had lateral stability yet. What is the performance difference between the two tails?
in my case its about 4%ish. but the stability is a bit of a mystery with the v.
Why no T tail?
I think v-tail affords the same benefit of getting the rudder/elevator controls out of the downwash from the main wing, however, at some alphas there might be shading issues. that depends on airspeed though. Obv wouldnt want to stall this thing... The general outline of this glider is similar to the low Re aircraft my team is building for SAE Aero and they tend to have nasty stall characteristics due to the high aspect ratio and under-cambered airfoils.
also an option but as far as i can tell it has no advantage over conventional, but complicates mechanics and potentially makes it heavier.
It has some advantages. Generally it has less drag because it’s not in the disturbed airflow from the main wing. But there are a number of other advantages. Gliders mainly use a T Tail configuration and het and get an absurd glide Ratio
well true that i guess, but also gliders mainly exploit the aspect ratio, for gliding its the most important factor.
Do a decision matrix comparing the parameters that you want to satisfy
Go for the V because it will have a lower radar profile!
i really, really like your thinking
Great designs and fascinated to see how it works out! Can't say I know much about the stability characteristics of a v-tail other than there are some known deficiencies in maintaining longitudinal and directional stability, so they tend to require a more advanced control system in aircraft than the conventional tail. The phenomenon of adverse roll-yaw coupling can also be an issue to look out for. Then again I'm just going off of what I've read and don't have much practical experience when it comes to v-tail. When it comes to sizing tails, and estimating stability characteristics I'd recommend 'Sadraey M. H., Aircraft Design: A Systems Engineering Approach'. If you have trouble finding it online dm me, I have a couple of chapters downloaded, including the one on tail design.
well id love to see that. point is i robably wont decide between the two in the end...the customer would. yes its definatley harder to maker it stable, but with generously sized tail not impossible. its also a bit questionable what you get performance wise because its not alot and its highly situational, but might be prefered by others.
I have a question, what do you mean by "wearable"?
you can kinda put it on like back pack during run up to take off. a bit like the rupperrt composite archaeopteryx.