CARBON FIBER DISCUSSION

[Piotrsko]

. So yeah the next few years should be very exciting as we will get to see a lot of these projects completed and in the air !

I wouldn't bet on that. Sonic was capable back in the '70s, might be one or two people worldwide capable today. Note that I said capable. Even all the cheap Russian stuff getting thrown at Ukraine is sub sonic, still. Tis why Zelensky desperately wants traumachickens (programmable supersonic 3ft accuracy out to 1000 km [depending on launch location accuracy])

 

[Zoom Master]

I wouldn't bet on that. Sonic was capable back in the '70s, might be one or two people worldwide capable today. Note that I said capable. Even all the cheap Russian stuff getting thrown at Ukraine is sub sonic, still. Tis why Zelensky desperately wants traumachickens (programmable supersonic 3ft accuracy out to 1000 km [depending on launch location accuracy])

Hmm we will just have to wait and see where student-run organizations like the mach initiative go with their high speed jet projects but im excited to see people like Joe manors projects and he is an actual professional with 20 years of experience (who's currently working at Prototyping Engineer at Joby Aviation) and is working with professional aerodynamists to make a sonic capable rc plane. Here is his forum https://www.rcgroups.com/forums/showthread.php?4715023-New-DS-Model-for-Supersonic-Flight-The-V/page5 its worth checking out and its pretty fun to read.

 

[Houndpup Rc]

I wouldn't bet on that. Sonic was capable back in the '70s, might be one or two people worldwide capable today. Note that I said capable. Even all the cheap Russian stuff getting thrown at Ukraine is sub sonic, still. Tis why Zelensky desperately wants traumachickens (programmable supersonic 3ft accuracy out to 1000 km [depending on launch location accuracy])

Though I would say its easier nowadays to do it, due to better electronics and higher technology.

 

[Zoom Master]

It is easier but most hobbyists like us do not posses the piloting or building skills (or money) to be able to build something that can go supersonic.

 

[Zoom Master]

Though I would say its easier nowadays to do it, due to better electronics and higher technology.

It is easier but most hobbyists like us do not posses the piloting or building skills (or money) to be able to build something that can go supersonic.

 

[Houndpup Rc]

It is easier but most hobbyists like us do not posses the piloting or building skills (or money) to be able to build something that can go supersonic.

That's true, I am just talking about tech...Like today's Fc's vs ones years ago.

 

[Piotrsko]

Afaik, +sonic is kinda the same as low speed based on all the 60's and '70s airfoil data except it is much draggier squared. The transition is goofy with airflow changes on the airfoil and COP movements but once you go through transition, it becomes a REALLY fast twitchy version of subsonic. You do need a dual rate radio, and much bigger place to fly, and the pressure wave off the wingtips is somewhat quieter (it's much smaller) but will annoy nearby homeowners at right angles to line of flight. Pretty sure the only people who can do this currently are the slopers, because they dont need thrust, but might be some jet turbine planes also, I dunno, not that much into supersonic. I do have a kinda aeroflot look alike "D" twin motor rocket, and IF it DOES goes sonic it is short duration when both motors light.

 

[Zoom Master]

You do need a dual rate radio, and much bigger place to fly, and the pressure wave off the wingtips is somewhat quieter (it's much smaller) but will annoy nearby homeowners at right angles to line of flight. Pretty sure the only people who can do this currently are the slopers, because they dont need thrust, but might be some jet turbine planes also, I dunno, not that much into supersonic. I do have a kinda aeroflot look alike "D" twin motor rocket, and IF it DOES goes sonic it is short duration when both motors light.

Well you obviously need a large place to fly....a light sport airport would be your best bet it's an airport where only light sport airplanes and ultralight aircrafts can take off and land (dont know if it's a thing over there in the US but its def a thing where I live) OR you can go to a large open grass field or the desert. You really wouldn't want to fly something that goes 500 + near any houses. If you are talking about going 500+ then you are sort of right. There are 3-4 dynamic soaring gliders that can and have gone 500+ but there is only 1 rc jet turbine that has gone 500 (allegedly) and only 2 that are capable of so (or at least to my knowledge).

 

[Piotrsko]

Can't typically mix full size and small RC aircraft at the full size airports I used to frequent. COULD land the 4 seat Pacer and get it back out, but that was frowned upon at the "hobby" airports and typically involved unhappy officials there, also.

 

[Zoom Master]

Afaik, +sonic is kinda the same as low speed based on all the 60's and '70s airfoil data except it is much draggier squared. The transition is goofy with airflow changes on the airfoil and COP movements but once you go through transition, it becomes a REALLY fast twitchy version of subsonic. You do need a dual rate radio, and much bigger place to fly, and the pressure wave off the wingtips is somewhat quieter (it's much smaller) but will annoy nearby homeowners at right angles to line of flight. Pretty sure the only people who can do this currently are the slopers, because they dont need thrust, but might be some jet turbine planes also, I dunno, not that much into supersonic. I do have a kinda aeroflot look alike "D" twin motor rocket, and IF it DOES goes sonic it is short duration when both motors light.

Wait a min dual band radios ? I was under the impression that a ELRS radio would be better for a sub sonic airplane rather than a dual band one.

 

[Zoom Master]

Can't typically mix full size and small RC aircraft at the full size airports I used to frequent. COULD land the 4 seat Pacer and get it back out, but that was frowned upon at the "hobby" airports and typically involved unhappy officials there, also.

Thats true but a large open field is still an option just get permission from the owners (or just buy it if you are filthy rich like Tyler Perry) and go have fun.

 

[Piotrsko]

Dual rate switch: one way is full deflection, the other is programmed for reduced significant Movement, but proportional to stick movement: half stick is half the surface movement halved. (Bit of a math answer)

first computer radios back about 1990. We thought we died and went to heaven because with the flip of a switch, twitchy became flyable.
Go buy yourself about 5 acres. I bought a bowl facing onto the wind for awesome slope soaring off the front porch. Then I had kids and driving a half hour for the twice daily school trip got old really fast.

 

[Zoom Master]

Dual rate switch: one way is full deflection, the other is programmed for reduced significant Movement, but proportional to stick movement: half stick is half the surface movement halved. (Bit of a math answer)

first computer radios back about 1990. We thought we died and went to heaven because with the flip of a switch, twitchy became flyable.
Go buy yourself about 5 acres. I bought a bowl facing onto the wind for awesome slope soaring off the front porch. Then I had kids and driving a half hour for the twice daily school trip got old really fast.

Alright good to know and btw should one be using an airfoil on the vertical and horizontal stabs and does it really affect the airplanes performance all that much ? And I ask once again is it a good idea for me to use a MH 54 airfoil for all my surfaces or should a I pick a different one for my vertical and horizontal stab ?

Asked chatgpt and it told me If im using a MH-54 profile for the wings I should use a NACA-0006 for the horizontal stab and a NACA-0008 for the vertical. Is this a good idea ? I ask as I am not the most knowledgeable on profiles and a dumb question is better than a dumb mistake.

 

[telnar1236]

Alright good to know and btw should one be using an airfoil on the vertical and horizontal stabs and does it really affect the airplanes performance all that much ? And I ask once again is it a good idea for me to use a MH 54 airfoil for all my surfaces or should a I pick a different one for my vertical and horizontal stab ?

Asked chatgpt and it told me If im using a MH-54 profile for the wings I should use a NACA-0006 for the horizontal stab and a NACA-0008 for the vertical. Is this a good idea ? I ask as I am not the most knowledgeable on profiles and a dumb question is better than a dumb mistake.

The MH airfoil wing and NACA tail are pretty near perfect for speed so long as you're using sufficiently strong materials for the flying surfaces. All of those are quite thin airfoils so there isn't as much structure to support the bending of the wings and tail. Depending on the size of the plane, it's also worth considering if an 8% thickness airfoil is thick enough to fit the required servos, etc. if you plan on putting them in the wing or vertical stabilizer. You might be able to use an upside MH54 airfoil for the horizontal stabilizer too, instead, since that would give you a bit of up trim without the penalty of drag from elevator deflection. If you need a thicker wing, the MH27 airfoil is pretty good - for my high speed jet design I found a 12% thickness wing was the minimum to fit the stuff I wanted to, but if you can get away with an 8% thickness wing, it's certainly lower drag to keep it thinner.

You definitely don't want the MH 54 for the vertical stabilizer - it looks symmetrical but actually has a 0.6% camber which means it would throw your plane noticeably out of trim.

 

[Zoom Master]

The MH airfoil wing and NACA tail are pretty near perfect for speed so long as you're using sufficiently strong materials for the flying surfaces. All of those are quite thin airfoils so there isn't as much structure to support the bending of the wings and tail. Depending on the size of the plane, it's also worth considering if an 8% thickness airfoil is thick enough to fit the required servos, etc. if you plan on putting them in the wing or vertical stabilizer. You might be able to use an upside MH54 airfoil for the horizontal stabilizer too, instead, since that would give you a bit of up trim without the penalty of drag from elevator deflection. If you need a thicker wing, the MH27 airfoil is pretty good - for my high speed jet design I found a 12% thickness wing was the minimum to fit the stuff I wanted to, but if you can get away with an 8% thickness wing, it's certainly lower drag to keep it thinner.

You definitely don't want the MH 54 for the vertical stabilizer - it looks symmetrical but actually has a 0.6% camber which means it would throw your plane noticeably out of trim.

Well alright seems like it's a good idea to go with a MH wing and a NACA tail so I'll go for that. And as for fitting in there servos I should be able to do that pretty easily without any major issues. And I am aware these thin airfoils dont have much structure so ill see what I can do about that.

 

[Piotrsko]

Ask the chatp gpt if you are capable of actually accurate building the desired profiles. I'll wait.................. then ask it for airflow modelling of the surfaces you built.
Have 3 servos out of a mini helicopter that would fit in 2 thicknesses of foamboard, so like 1/4-5/16" thick nickle sized, therefore thin airfoil is a function of cash/parts on hand

 

[Zoom Master]

Ask the chatp gpt if you are capable of actually accurate building the desired profiles. I'll wait.................. then ask it for airflow modelling of the surfaces you built.
Have 3 servos out of a mini helicopter that would fit in 2 thicknesses of foamboard, so like 1/4-5/16" thick nickle sized, therefore thin airfoil is a function of cash/parts on hand

Well I asked and it said "Yes — absolutely 👍" So there is at least one thing that believes in me 😂 And It isn't really that hard to find servos that will fit inside these thin profiles. There are a lot of servos out there that will fit but the catch is that they are pricey.

 

[Piotrsko]

Aircraft flight is equal to the weight of paperwork or money involved being more than the weight of the plane

 

[telnar1236]

Well I asked and it said "Yes — absolutely 👍" So there is at least one thing that believes in me 😂 And It isn't really that hard to find servos that will fit inside these thin profiles. There are a lot of servos out there that will fit but the catch is that they are pricey.

Also look at the torque from the servos - it doesn't matter if they fit if they can't move the control surface. Mid7Night has a calculator spreadsheet that gives an estimate of the required torque and there are also calculators online to do the same thing.

Using carbon fiber wrapped around a hot wire cut foam section it's not all that awful to get good airfoil profiles if the wing has a constant taper. If you go for an elliptical wing or something with rounded wingtips, it's a different story and enormously frustrating and difficult to do. Personally, I'd recommend 3D printing since it's easy and more precise than anything you can hotwire cut, but before any of the above, at the very least I'd suggest making a chuck glider out of foam board with the understanding that you won't get the airfoil sections perfect.

 

[Zoom Master]

Also look at the torque from the servos - it doesn't matter if they fit if they can't move the control surface. Mid7Night has a calculator spreadsheet that gives an estimate of the required torque and there are also calculators online to do the same thing.

Using carbon fiber wrapped around a hot wire cut foam section it's not all that awful to get good airfoil profiles if the wing has a constant taper. If you go for an elliptical wing or something with rounded wingtips, it's a different story and enormously frustrating and difficult to do. Personally, I'd recommend 3D printing since it's easy and more precise than anything you can hotwire cut, but before any of the above, at the very least I'd suggest making a chuck glider out of foam board with the understanding that you won't get the airfoil sections perfect.

Well thats true but my airplane has these rounded wingtips that will be very annoying and hard to make using foam so I'll have to see. But I was planning on using the MH 54 profile and NACA tail on a foamboard speedwing. The wing shouldn't be to hard hopefully but the tail might be a bit tricky so I'll have to see. Not gonna build currently as I have to save up for all the expensive electronics that will go in it and need to complete a few other projects im working on before I start a new one 😅