Wing Section for a New Bipe.
08-27-2013, 01:48 AM
#1
Thread Starter
Wing Section for a New Bipe.
Hi Guys,
I'm thinking about a scratch build (it's been 17 years since my last one).
I'm looking at a bipe but it needs to be light.
Can anyone recommend a particular section or two for the wings and %'s at root and tip.
Needs to work well in a relatively thin wing.
Also a tail section would be good - requirements here are different.
Brian
I'm thinking about a scratch build (it's been 17 years since my last one).
I'm looking at a bipe but it needs to be light.
Can anyone recommend a particular section or two for the wings and %'s at root and tip.
Needs to work well in a relatively thin wing.
Also a tail section would be good - requirements here are different.
Brian
08-27-2013, 10:47 AM
#4
Senior Member
Mine are not bipes but it doesn't really matter. I use 10% wing roots and have found I really like 9% at the tips. Coupled with my very narrow tip chords, thinner tips enhance a foil's ability to build a smaller LE radius there, critical to snaps and spins being done crisply with precision and character. For a bipe's wing, thinner foils buy little since the chords are usually smaller and LE radii even smaller than on monos. Yet another reason why bipes should work the current schedules better.....
For stabs, determining what thickness you need if you want servos burried, will drive thickness percent up to a point. I try to never use more than 12% tho. I've found that thicker % stabs tend to mush in pitch and I don't like them as much as thinner %. I will compromise a bit by increasing root chord some and keeping the % thickness unchanged, in order to drive thickness up for servos. One man's philosophy on design parameters, of course
Last edited by MTK; 08-27-2013 at 10:49 AM.
08-27-2013, 12:19 PM
#5
Thread Starter
Hi Matt,
Thanks, I really appreciate the input. I was hoping you would chime in.
The last thing I built like this was a R.Chidgey Typhoon 2+2.
A few of us here collaborated , got some fuz mouldings (they were good/great very light and strong) and scratch built the rest loosely based on the plan.
Funny thing is, I did all the wings just like you just suggested ;increased % at the root and reduced chord and % at the tip. It would snap on a six-pence (dime) and you could have a cup of tea while it did a set of spins (if you wanted too).
I'm hoping to do likewise this time - subject to getting my hands on a suitable fuz moulding - I have a particular option in mind + a back up.
I like the flying stab idea - light too - I used them on aerobatic slope soarer's for years. So thickness should not be an issue. Considering this how thin would you go with the stab ?
This will be propelled by Brenner's contra.
Can you speak to the relationship between high point position and CG position ??
Again thank you
Brian
Thanks, I really appreciate the input. I was hoping you would chime in.
The last thing I built like this was a R.Chidgey Typhoon 2+2.
A few of us here collaborated , got some fuz mouldings (they were good/great very light and strong) and scratch built the rest loosely based on the plan.
Funny thing is, I did all the wings just like you just suggested ;increased % at the root and reduced chord and % at the tip. It would snap on a six-pence (dime) and you could have a cup of tea while it did a set of spins (if you wanted too).
I'm hoping to do likewise this time - subject to getting my hands on a suitable fuz moulding - I have a particular option in mind + a back up.
I like the flying stab idea - light too - I used them on aerobatic slope soarer's for years. So thickness should not be an issue. Considering this how thin would you go with the stab ?
This will be propelled by Brenner's contra.
Can you speak to the relationship between high point position and CG position ??
Again thank you
Brian
08-27-2013, 05:26 PM
#6
My Feedback: (34)
If you go with the flying stab, use the SD8020 for the tail. It was specifically designed for flying stabs with very low drag rise as a function of angle of attack all the way to critical AOA. So you'll get very good stab response without losing energy when generating pitch changes.
08-27-2013, 09:46 PM
#7
Senior Member
No problem Brian, you're welcome.
On stab thickness, I've used as small a thickness as 5/8" at the high point and as large as what I have now in my current ride, Aesthesis, which is 1 1/4" thick at the high point. There was nothing wrong with the 5/8 thickness (6 1/2%) at the root and the same % at the tip. The current model with the thicker stab has 11% section. My newest, Delta in in between. Of the 3 I like Temptress' 6 1/2% and Delta's 8% better than Aesthesis' 11%. Pitch response is crisper.....Not 100% sure it is only foil doing that tho...
The contra demands gobs of yaw stability. Your vertical tail volume coefficient probably needs to be around 1.4 to avoid most of the appendages folks have resorted to. Increased fin span I think is the key. Also, bringing the canopy aft helps
The current crop of planes have vertical TVC's of around 1.2 give or take
CG versus high point....don't have enough data on that one to make a judgement. I have some foam cut to a similar exponential curve I mentioned earlier, except the high point is at 25%. One of these days I need to complete the experiment and see what difference if any, exists. The CG is a function of moments, planforms and areas, that's it
Flying stabs make alot of sense in aerobatic models for extreme aerobatics. Unfortunately we've had a few early botched attempts so folks are reluctant to try them again. The biggest drawback is balance weight so far back on the model. And getting the pivot located right which dictates how much balance weight is needed. Some of these issues could be reduced with judicious actuation point. The actuation could use a moment arm away from the pivot
Hopefully that makes sense...it's late and i need to go nanni
On stab thickness, I've used as small a thickness as 5/8" at the high point and as large as what I have now in my current ride, Aesthesis, which is 1 1/4" thick at the high point. There was nothing wrong with the 5/8 thickness (6 1/2%) at the root and the same % at the tip. The current model with the thicker stab has 11% section. My newest, Delta in in between. Of the 3 I like Temptress' 6 1/2% and Delta's 8% better than Aesthesis' 11%. Pitch response is crisper.....Not 100% sure it is only foil doing that tho...
The contra demands gobs of yaw stability. Your vertical tail volume coefficient probably needs to be around 1.4 to avoid most of the appendages folks have resorted to. Increased fin span I think is the key. Also, bringing the canopy aft helps
The current crop of planes have vertical TVC's of around 1.2 give or take
CG versus high point....don't have enough data on that one to make a judgement. I have some foam cut to a similar exponential curve I mentioned earlier, except the high point is at 25%. One of these days I need to complete the experiment and see what difference if any, exists. The CG is a function of moments, planforms and areas, that's it
Flying stabs make alot of sense in aerobatic models for extreme aerobatics. Unfortunately we've had a few early botched attempts so folks are reluctant to try them again. The biggest drawback is balance weight so far back on the model. And getting the pivot located right which dictates how much balance weight is needed. Some of these issues could be reduced with judicious actuation point. The actuation could use a moment arm away from the pivot
Hopefully that makes sense...it's late and i need to go nanni
08-27-2013, 10:52 PM
#8
Hello Brian
First version of the bip has wingspan 1,80 m et thickness chord 10 % .
So he wanted to decrease drag and version 2 has wingspan 1,70 m and chord thiness 8 %.
We uses logiciel Tracfoil to draw airfoil :
http://tracfoil.free.fr/tracfoil/accueilE.htm
Thanks to Matt and Doug to answer.
Claude
First version of the bip has wingspan 1,80 m et thickness chord 10 % .
So he wanted to decrease drag and version 2 has wingspan 1,70 m and chord thiness 8 %.
We uses logiciel Tracfoil to draw airfoil :
http://tracfoil.free.fr/tracfoil/accueilE.htm
Thanks to Matt and Doug to answer.
Claude
08-27-2013, 11:55 PM
#10
Thread Starter
Doug,Matt,Claude,
Thanks for the input. I will check into all that. I'm just at concept stage and won't really get into this till Oct,, ,but will get wing/stab kits put together in the meantime.
Re the yaw stability I have those things in mind - also I'm moving the wing forward a little and sweeping the tips aft some. Net result will be to move the CG 25mm forward in the fuz. So I will get a reasonable re-distribution of side area to aft of the CG and a corresponding moment increase. Also should get a 'dihedral' effect in yaw due to the sweep.
Matt; By 'balance weight' do you mean; so as to balance the stab at the pivot or dynamically.
Brian
Thanks for the input. I will check into all that. I'm just at concept stage and won't really get into this till Oct,, ,but will get wing/stab kits put together in the meantime.
Re the yaw stability I have those things in mind - also I'm moving the wing forward a little and sweeping the tips aft some. Net result will be to move the CG 25mm forward in the fuz. So I will get a reasonable re-distribution of side area to aft of the CG and a corresponding moment increase. Also should get a 'dihedral' effect in yaw due to the sweep.
Matt; By 'balance weight' do you mean; so as to balance the stab at the pivot or dynamically.
Brian
08-28-2013, 05:50 PM
#11
Senior Member
Static balance. Teeter totter at the pivot. It will take about a couple ounces so making the stab really light will be important later. Also a lighter one takes less weight to balance.
Good luck with the plane Brian.
Good luck with the plane Brian.
08-28-2013, 06:18 PM
#12
My Feedback: (34)
Doug,Matt,Claude,
Thanks for the input. I will check into all that. I'm just at concept stage and won't really get into this till Oct,, ,but will get wing/stab kits put together in the meantime.
Re the yaw stability I have those things in mind - also I'm moving the wing forward a little and sweeping the tips aft some. Net result will be to move the CG 25mm forward in the fuz. So I will get a reasonable re-distribution of side area to aft of the CG and a corresponding moment increase. Also should get a 'dihedral' effect in yaw due to the sweep.
Matt; By 'balance weight' do you mean; so as to balance the stab at the pivot or dynamically.
Brian
Thanks for the input. I will check into all that. I'm just at concept stage and won't really get into this till Oct,, ,but will get wing/stab kits put together in the meantime.
Re the yaw stability I have those things in mind - also I'm moving the wing forward a little and sweeping the tips aft some. Net result will be to move the CG 25mm forward in the fuz. So I will get a reasonable re-distribution of side area to aft of the CG and a corresponding moment increase. Also should get a 'dihedral' effect in yaw due to the sweep.
Matt; By 'balance weight' do you mean; so as to balance the stab at the pivot or dynamically.
Brian
08-28-2013, 11:14 PM
#13
Thread Starter
Hi Doug,
Yes, there is not that much 'knowledge' out there re bipes.
I have been flying them for a number of years now and have gained some experience.
Any yaw stability , while using the contra, is most manifest while doing inside 1/4 loops to and from vertical.
I am trying a number of things, including more sweep, on this to try to get that better.
Any thoughts on thickness % for that section you mentioned for the stab ?
Btw I see on the Biside thread that it is recommended to set the top wing incidence at 0.5 negative relative to the bottom wing. I have been setting them the same as each other.
About 4 years ago I had them set like that ,but with less difference. To improve the yaw stability I moved to a more forward CG and it flew too heavy.
Thanks.
Brian
Yes, there is not that much 'knowledge' out there re bipes.
I have been flying them for a number of years now and have gained some experience.
Any yaw stability , while using the contra, is most manifest while doing inside 1/4 loops to and from vertical.
I am trying a number of things, including more sweep, on this to try to get that better.
Any thoughts on thickness % for that section you mentioned for the stab ?
Btw I see on the Biside thread that it is recommended to set the top wing incidence at 0.5 negative relative to the bottom wing. I have been setting them the same as each other.
About 4 years ago I had them set like that ,but with less difference. To improve the yaw stability I moved to a more forward CG and it flew too heavy.
Thanks.
Brian
08-29-2013, 04:40 AM
#15
Firstly Brian it's great to see Ireland still at the forefront of European aerobatic flying. Hopefully your home brewed bipe will add to a long list including composite construction, 4 strokes, electric power, contradrives to name a few.
Like Doug I would be wary of sweepback. It moves the aerodynamic centre of the wing back and with it the neutral point of the aeroplane and so you are negating the increase in yaw stability you will be gaining by moving the wings forward. Yaw/roll couple is always a problem with bipes which is why you see the latest designs moving the wings closer together and introducing anhedral to the top wing. Anything that promotes yaw/roll couple, even if it is with angle of attack is to be avoided.
Moving away from the aerodynamics for a minute, remember I commented to you at the Triple Crown that your Mid Rex only looks like a bipe some of the time flying through the schedule? To me its important that it looks like a bipe the whole time and its something your Venture did very well. You might think about this when you position the wings with respect to one another and the fuz. The yaw/roll couple with wing separation needs to be addressed and one area where small improvements might be made is in the vertical centre of gravity of the model. I suspect that getting the weight i.e. the batteries as low as possible may help a little.
Structurally the flying surfaces need to be as stiff as possible. To this end I'm not keen on film covering and I'm certainly put off the Biside by the instructions on how to remove the warps due to the very light balsa used in the construction to make weight. I think you need to consider imaginative solutions such as fully geodetic construction which with laser cutting is not difficult. An all flying tail is a great idea, has been proved aerodynamically on the Biside and does away with control surfaces to warp so perfect for geodetics. Actually the same argument applies to the wings. Ailerons are just something to warp so why not do away with them and go for all flying wings also geodetically built? This isn't as daft as it sounds with the wing panels pivoting on thin section ball raced tubes and driven by S-bus high voltage servos. There is one now which gives 38kg.cm of torque and 0.082s/60deg! As an aside HV S-bus is looking to be a great way to go weight wise, with two servos in the tail and four in the wings and one 3 core cable feeding them. I know that camber is more effective than angle of attack at changing lift but years ago there were a few successful aerobatic soarers which used wing twist and they flew very well.
I hope this might give you a few ideas to play with and you know the address to send the plans to!
Malcolm
Like Doug I would be wary of sweepback. It moves the aerodynamic centre of the wing back and with it the neutral point of the aeroplane and so you are negating the increase in yaw stability you will be gaining by moving the wings forward. Yaw/roll couple is always a problem with bipes which is why you see the latest designs moving the wings closer together and introducing anhedral to the top wing. Anything that promotes yaw/roll couple, even if it is with angle of attack is to be avoided.
Moving away from the aerodynamics for a minute, remember I commented to you at the Triple Crown that your Mid Rex only looks like a bipe some of the time flying through the schedule? To me its important that it looks like a bipe the whole time and its something your Venture did very well. You might think about this when you position the wings with respect to one another and the fuz. The yaw/roll couple with wing separation needs to be addressed and one area where small improvements might be made is in the vertical centre of gravity of the model. I suspect that getting the weight i.e. the batteries as low as possible may help a little.
Structurally the flying surfaces need to be as stiff as possible. To this end I'm not keen on film covering and I'm certainly put off the Biside by the instructions on how to remove the warps due to the very light balsa used in the construction to make weight. I think you need to consider imaginative solutions such as fully geodetic construction which with laser cutting is not difficult. An all flying tail is a great idea, has been proved aerodynamically on the Biside and does away with control surfaces to warp so perfect for geodetics. Actually the same argument applies to the wings. Ailerons are just something to warp so why not do away with them and go for all flying wings also geodetically built? This isn't as daft as it sounds with the wing panels pivoting on thin section ball raced tubes and driven by S-bus high voltage servos. There is one now which gives 38kg.cm of torque and 0.082s/60deg! As an aside HV S-bus is looking to be a great way to go weight wise, with two servos in the tail and four in the wings and one 3 core cable feeding them. I know that camber is more effective than angle of attack at changing lift but years ago there were a few successful aerobatic soarers which used wing twist and they flew very well.
I hope this might give you a few ideas to play with and you know the address to send the plans to!
Malcolm
08-29-2013, 03:09 PM
#17
Thread Starter
Hi Claude,
Thanks, I had not seen that before - or that web site.
Malcolm, thanks for the input - keep it coming ,it's all needed.
Also there is this , and Mr Naruke seems happy with some sweep in the wings ??;
Thanks, I had not seen that before - or that web site.
Malcolm, thanks for the input - keep it coming ,it's all needed.
Also there is this , and Mr Naruke seems happy with some sweep in the wings ??;
08-29-2013, 03:44 PM
#19
Thread Starter
Thanks for the input, it's much appreciated.
Re the sweep ; that's what I thought.
Brian
08-30-2013, 02:57 AM
#20
Thread Starter
Firstly Brian it's great to see Ireland still at the forefront of European aerobatic flying. Hopefully your home brewed bipe will add to a long list including composite construction, 4 strokes, electric power, contradrives to name a few.
Like Doug I would be wary of sweepback. It moves the aerodynamic centre of the wing back and with it the neutral point of the aeroplane and so you are negating the increase in yaw stability you will be gaining by moving the wings forward. Yaw/roll couple is always a problem with bipes which is why you see the latest designs moving the wings closer together and introducing anhedral to the top wing. Anything that promotes yaw/roll couple, even if it is with angle of attack is to be avoided.
Moving away from the aerodynamics for a minute, remember I commented to you at the Triple Crown that your Mid Rex only looks like a bipe some of the time flying through the schedule? To me its important that it looks like a bipe the whole time and its something your Venture did very well. You might think about this when you position the wings with respect to one another and the fuz. The yaw/roll couple with wing separation needs to be addressed and one area where small improvements might be made is in the vertical centre of gravity of the model. I suspect that getting the weight i.e. the batteries as low as possible may help a little.
Structurally the flying surfaces need to be as stiff as possible. To this end I'm not keen on film covering and I'm certainly put off the Biside by the instructions on how to remove the warps due to the very light balsa used in the construction to make weight. I think you need to consider imaginative solutions such as fully geodetic construction which with laser cutting is not difficult. An all flying tail is a great idea, has been proved aerodynamically on the Biside and does away with control surfaces to warp so perfect for geodetics. Actually the same argument applies to the wings. Ailerons are just something to warp so why not do away with them and go for all flying wings also geodetically built? This isn't as daft as it sounds with the wing panels pivoting on thin section ball raced tubes and driven by S-bus high voltage servos. There is one now which gives 38kg.cm of torque and 0.082s/60deg! As an aside HV S-bus is looking to be a great way to go weight wise, with two servos in the tail and four in the wings and one 3 core cable feeding them. I know that camber is more effective than angle of attack at changing lift but years ago there were a few successful aerobatic soarers which used wing twist and they flew very well.
I hope this might give you a few ideas to play with and you know the address to send the plans to!
Malcolm
Like Doug I would be wary of sweepback. It moves the aerodynamic centre of the wing back and with it the neutral point of the aeroplane and so you are negating the increase in yaw stability you will be gaining by moving the wings forward. Yaw/roll couple is always a problem with bipes which is why you see the latest designs moving the wings closer together and introducing anhedral to the top wing. Anything that promotes yaw/roll couple, even if it is with angle of attack is to be avoided.
Moving away from the aerodynamics for a minute, remember I commented to you at the Triple Crown that your Mid Rex only looks like a bipe some of the time flying through the schedule? To me its important that it looks like a bipe the whole time and its something your Venture did very well. You might think about this when you position the wings with respect to one another and the fuz. The yaw/roll couple with wing separation needs to be addressed and one area where small improvements might be made is in the vertical centre of gravity of the model. I suspect that getting the weight i.e. the batteries as low as possible may help a little.
Structurally the flying surfaces need to be as stiff as possible. To this end I'm not keen on film covering and I'm certainly put off the Biside by the instructions on how to remove the warps due to the very light balsa used in the construction to make weight. I think you need to consider imaginative solutions such as fully geodetic construction which with laser cutting is not difficult. An all flying tail is a great idea, has been proved aerodynamically on the Biside and does away with control surfaces to warp so perfect for geodetics. Actually the same argument applies to the wings. Ailerons are just something to warp so why not do away with them and go for all flying wings also geodetically built? This isn't as daft as it sounds with the wing panels pivoting on thin section ball raced tubes and driven by S-bus high voltage servos. There is one now which gives 38kg.cm of torque and 0.082s/60deg! As an aside HV S-bus is looking to be a great way to go weight wise, with two servos in the tail and four in the wings and one 3 core cable feeding them. I know that camber is more effective than angle of attack at changing lift but years ago there were a few successful aerobatic soarers which used wing twist and they flew very well.
I hope this might give you a few ideas to play with and you know the address to send the plans to!
Malcolm
The glider guys ,who I try to stay in touch with, are very innovative.
There are some great systems for all moving wings developed at this stage - complicated to do on a bipe with skinny and light wings.
They also are way out there with wing construction.
I just can't justify the effort required to create plugs,moulds and then mouldings for a one off - for wings or fuz,, .
( There is too much nice stuff out there ,available and little work to do
. )As you know I've been there before, but back then there was little or nothing ,of any quality, available.
i was tempted and I have developed some thoughts on fuz,, design to control flows , inside and out.
Also ,for these difficult knife edge based manoeuvres, a fuz,, that develops lift effectively, a stable wing and stab platform coupled with a contra is clearly the way to go.
If the entire platform is stable enough then the contra will really shine as it will not disturb it nearly as much as a single prop set up will while transitioning through the AOA's required for the KE based forms.
However flying at that level is not something that I have to worry about
.I just really enjoy the biplanes and they give me that little extra time as they still fly well at the somewhat slower speeds.
Weight is my real motivation here.
I'm fed up with having to use a small battery to be comp,, legal.
My aim is to get a bipe comp,, legal with a 5800 to 6000mAh on board.
I have to use 4400's at present and practising with these in our weather is not working all that great as it's too easy to 'hurt' them.
So I've decided that while I'm at it I will try a few little things just to do something that's new/fresh so as to keep the interest up.
I want a little more stability, particularly in yaw, so as to get my P schedule as good as I can.
I'm hoping to do this and have glassed skins - I'm not sure that there is even tissue on my current ones.
With glassed skins and good struts it will easily be stiff enough.
My current set up is not bad now but it did require attention. I have carbon packing shims on the heels and toes of the strut bases to tighten and set the fits.
The model is much better that it was at the Triple Crown.
Re the look; I don't altogether agree with you on that. These are F3A planes first and foremost.
The monos don't really look like anything other than what they are so why should the bipes.
So for me it's function first - then we'll see re the form.
Brian
11-21-2013, 03:24 AM
#21
Thread Starter
Hi,
This is as mostly a 'bump' as requested.
However while here I can say that I have now decided against the flying tail.
Right or wrong I have decided that the elevator is one of the single point failure modes that can wipe out a model.
I have been using a single servo pull pull on bipes to make weight and have gotten 'away' with it so far.
Now I'm going to use a smaller servo of some type ,maybe 15g to 20g and go back to using one in each tail half for redundancy.
I was using a single BLS153 at 26g for the pull pull.
Brian
This is as mostly a 'bump' as requested.
However while here I can say that I have now decided against the flying tail.
Right or wrong I have decided that the elevator is one of the single point failure modes that can wipe out a model.
I have been using a single servo pull pull on bipes to make weight and have gotten 'away' with it so far.
Now I'm going to use a smaller servo of some type ,maybe 15g to 20g and go back to using one in each tail half for redundancy.
I was using a single BLS153 at 26g for the pull pull.
Brian
11-21-2013, 09:43 AM
#22
Thread Starter
Hi Matt,
Received the carbon veil yesterday and had a chance to have a look at it today. Just one more delivery and then I'm all set to start. Can't believe all the stuff needed as all my old building stuff was either used or dumped - ARF's !!!
Anyway I got 0.2oz and 0.3oz.
The 0.3oz is actually 0,33oz and it is much more substantial than the 0.2oz.
It seems more dense as well to being deeper in section. I think this will be better on the outside as should have a little more meat to bite into when sanding.
So to go 0.2 oz inside and 0.3oz outside will take 7g of veil inside and 12g to 15g of veil outside per wing. Time will tell how much dope,filler and primer to get paint ready.
But this will have to be an extremely strong and stiff wing.
Also I can glue the skins to the cores for between 20g and 25g per wing as well. Have done some testing on this.
Time will tell now - busy for the next week or 2 but will get stuck in then.
Brian
Received the carbon veil yesterday and had a chance to have a look at it today. Just one more delivery and then I'm all set to start. Can't believe all the stuff needed as all my old building stuff was either used or dumped - ARF's !!!
Anyway I got 0.2oz and 0.3oz.
The 0.3oz is actually 0,33oz and it is much more substantial than the 0.2oz.
It seems more dense as well to being deeper in section. I think this will be better on the outside as should have a little more meat to bite into when sanding.
So to go 0.2 oz inside and 0.3oz outside will take 7g of veil inside and 12g to 15g of veil outside per wing. Time will tell how much dope,filler and primer to get paint ready.
But this will have to be an extremely strong and stiff wing.
Also I can glue the skins to the cores for between 20g and 25g per wing as well. Have done some testing on this.
Time will tell now - busy for the next week or 2 but will get stuck in then.
Brian
11-21-2013, 02:41 PM
#23
Senior Member
Hi Brian,
I really like the 0.3 veil but only when bagging and can squeeze every last xcess gram out of the stuff. The 0.2 on the other hand is so thin that it doesn't matter that much. Im sure you will be very careful and cognizant of the weight build up.
I also have 0.5 veil and this stuff is really thick. Almost impossible to build light with it. Probably needs to have dacron textile applied on outside to draw out the epoxy under vacuum.
Besides, the 0.2 ounce stock will produce a surprisingly stiff wing. You probably don't need it full span either....maybe to where the interplane struts attach. Wish you lots of luck and success
I really like the 0.3 veil but only when bagging and can squeeze every last xcess gram out of the stuff. The 0.2 on the other hand is so thin that it doesn't matter that much. Im sure you will be very careful and cognizant of the weight build up.
I also have 0.5 veil and this stuff is really thick. Almost impossible to build light with it. Probably needs to have dacron textile applied on outside to draw out the epoxy under vacuum.
Besides, the 0.2 ounce stock will produce a surprisingly stiff wing. You probably don't need it full span either....maybe to where the interplane struts attach. Wish you lots of luck and success
11-21-2013, 03:28 PM
#24
Thread Starter
Matt,
Thanks.
I had noticed ,on your thread, that it's easy to go through the 0.2oz.
I'm thinking that I should be able to fill the 0.3oz and take the top of it so to speak while flatting. This assumes a reasonably flat surface to begin with.
It should be a little more tolerant of the flatting process in that there is more depth to it . I'm thinking that with sanding I should get it to the equivalent having 0.2oz to 0.25oz of veil allbeit with local variances from 0.15oz to 0.3oz.
I will of course have a completely intact 0.2oz layer of veil underneath.
Yes I will watch how the weight builds. I'm looking forward to seeing just how strong this gets assuming the weight is kept under control.
I'm sure you are correct about not needing it full span or double sided for that matter. I can vary the aggressiveness of the flatting as I go out span-wise.
However I have to agree with the guys re the need for stiffness and strength on these skinny wings. They are quite different from mono wings in that regard.
So I'm using a combo of your method and some lightening methods to see what can be achieved.
This may help others in due course.
Brian
Thanks.
I had noticed ,on your thread, that it's easy to go through the 0.2oz.
I'm thinking that I should be able to fill the 0.3oz and take the top of it so to speak while flatting. This assumes a reasonably flat surface to begin with.
It should be a little more tolerant of the flatting process in that there is more depth to it . I'm thinking that with sanding I should get it to the equivalent having 0.2oz to 0.25oz of veil allbeit with local variances from 0.15oz to 0.3oz.
I will of course have a completely intact 0.2oz layer of veil underneath.
Yes I will watch how the weight builds. I'm looking forward to seeing just how strong this gets assuming the weight is kept under control.
I'm sure you are correct about not needing it full span or double sided for that matter. I can vary the aggressiveness of the flatting as I go out span-wise.
However I have to agree with the guys re the need for stiffness and strength on these skinny wings. They are quite different from mono wings in that regard.
So I'm using a combo of your method and some lightening methods to see what can be achieved.
This may help others in due course.
Brian