NEXT LEVEL P-40 Group Build

[Sero]

I see you are using flaps but no landing gear, I'm guessing there isn't an issue with the flaps dragging on the ground at all being that the under wing vent helps. And are those split flaps? And it also looks like you use Master Airscrew props, What's your thoughts on those?

I am trying to figure if the advantage for the under camber tips out weighs the aerodynamic gains of a speed wing like what you are sowing me and what I have seen nn build. I did watch a couple of his vids today, the one you posted and a speed wing specific build vid, and his Mig 3 maiden. Seems the drag of the under camber is more of an disadvantage then the gains of reducing tip stall. Maybe its just that I haven't flown a speed wing yet. If i build one what should I expect?

@Headbang is not a big fan of warbirds so I have an idea of what he will say, actually he told me to build a Mig 3 lol, so it's hard to tell lol.

I see you have Canadian roundels on you Stang as well, where do you live?

Yes with the Mustang the flaps don't drag due to the bottom vent. With the Racer I'll retract to half flaps just before touch down. If your using flaps its good to have the servo arms pointing as far forward as possible so the linkage rods as near parallel to the arms when fully deployed, this will keep the strain off your servo gears if the flaps hit something. Let me know if this doesn't make sense and you need me to elaborate.

I really quite like the speed wing, everybody has covered the differences well. It definitely is not for the new flyer. On a maiden after trimming I go through a few things to learn the characteristics of the plane including what it does at stall, i highly recommend this with the speed wing.

When designing and building a plane with an airfoiled tail I try to keep tail weight in mind as much as possible. Moving the tail servos forward, substituting hot glue with a lighter option or using less glue. It all helps. Also It most cases I use bigger motors and ESCs too which obviously helps a lot.

Im near Vancouver BC.

 

[Sero]

And it also looks like you use Master Airscrew props, What's your thoughts on those?

No complaints with them. Occasionally not as well balanced as I would like but that seems to be the norm with most brands. They are strong, perform well and are generally quieter than the average.

 

[BATTLEAXE]

Yes with the Mustang the flaps don't drag due to the bottom vent. With the Racer I'll retract to half flaps just before touch down. If your using flaps its good to have the servo arms pointing as far forward as possible so the linkage rods as near parallel to the arms when fully deployed, this will keep the strain off your servo gears if the flaps hit something. Let me know if this doesn't make sense and you need me to elaborate.

I really quite like the speed wing, everybody has covered the differences well. It definitely is not for the new flyer. On a maiden after trimming I go through a few things to learn the characteristics of the plane including what it does at stall, i highly recommend this with the speed wing.

When designing and building a plane with an airfoiled tail I try to keep tail weight in mind as much as possible. Moving the tail servos forward, substituting hot glue with a lighter option or using less glue. It all helps. Also It most cases I use bigger motors and ESCs too which obviously helps a lot.

Im near Vancouver BC.

I do know what you mean about the servos for the flaps, and it is a good idea i wasn't thinking of. I actually do something similar with the aileron servos after they are centered, I move the arm one notch forward for the mechanical advantage on the upswing to help with adverse yaw. Building a new wing will allow me to plan better for landing gear as well if I decide to go that direction. I totally forgot that in my current wing and pigeon holed myself. I will just put in the reinforcements so I can make that decision at a later date.

I love Vancouver btw. All my family lives on the island. I used to live in Whistler for 4 years. I want to move back so bad. Lucky you

 

[BATTLEAXE]

No complaints with them. Occasionally not as well balanced as I would like but that seems to be the norm with most brands. They are strong, perform well and are generally quieter than the average.

I have tried both the Master Airscrew and APC. I really like the APC performance, it is quit noticeable even to my novice experience level. I do use a master airscrew on the Bronco as a pusher, which is noisy anyway lol.

Thanks for all your advice btw. It has been super helpful

 

[degriz]

I am going to watch his P-39 vid front to back again to get all the tricks down. That's a really good suggestion and in my head I was thinking that's what I was going to have to do, just not how to go about it. Like yours I am looking to build a plane that is capable of some decent speeds and still do some lofty slower passes like a Spit. I want to be able to streamline this as much as possible and every little bit counts.

Doing the double up folded tail feathers adds more weight to the tail, how do you compensate for the balance on that or is it even a concern?

There is a wealth of info coming out of this thread, very impressed so far. And I am sure there is more to come. I pm'd @Hai-Lee to check it out and get his input on it, and he came up all spades on this. So happy he is around to help... like I said before, he is like Yoda. The step transition from the bottom panel to the under camber tips half way along the length of the aileron is something that I don't think I will be able to get away from unless the LE of the aileron is two different thickness's, so those little vortex's will be present between the TE of the bottom panel and the underside of the aileron flap on the inner half... another thinker. Another reason I need to watch the P-39 vid.

Do you tend to fly with a lot of rudder or is it just nice to have when you need it?

My Spit was a AET 3 channel and so i never used it there and I barely use it on my 4 channels although I am tending to use it more as I get better in flying skills and more daring as well.

Yes I enjoy flying with rudder, The large area of the P-40 makes it a lot of fun to throw around the sky.

 

[Sero]

I do know what you mean about the servos for the flaps, and it is a good idea i wasn't thinking of. I actually do something similar with the aileron servos after they are centered, I move the arm one notch forward for the mechanical advantage on the upswing to help with adverse yaw. Building a new wing will allow me to plan better for landing gear as well if I decide to go that direction. I totally forgot that in my current wing and pigeon holed myself. I will just put in the reinforcements so I can make that decision at a later date.

I love Vancouver btw. All my family lives on the island. I used to live in Whistler for 4 years. I want to move back so bad. Lucky you

I fly at a family farm (and recently at a club) and with the fast planes at that location I have to land in a field that at some times the grass is as tall as me, so no need for wheels. I also prefer the look of no landing gear. Perhaps one day I'll do retracts for the grass strip at the club buts its gentle on belly landing there too.

 

[Hai-Lee]

Be careful when rounding the TEs as the round profile whilst strong actually changes the airflow direction very rapidly and directs the two airflows into each other head on! The round shape can also cause the airflow at the TE to "Lift" at stall and even increase the stall speed. A square cut TE is best BUT it should not be too thick a TE of too thin!

Like everything it is a compromise but a true rounding may give weird results and even increased flutter if your bird is a very fast bird!

Give it a shot and post what you find or discover!

Have fun!

 

[BATTLEAXE]

Be careful when rounding the TEs as the round profile whilst strong actually changes the airflow direction very rapidly and directs the two airflows into each other head on! The round shape can also cause the airflow at the TE to "Lift" at stall and even increase the stall speed. A square cut TE is best BUT it should not be too thick a TE of too thin!

Like everything it is a compromise but a true rounding may give weird results and even increased flutter if your bird is a very fast bird!

Give it a shot and post what you find or discover!

Have fun!

Haha as much as you strive to make things easier and understandable, it also gets more difficult to make choices lol. All things considered it will end up to what happens in the moment of the build. I would like to build a speed wing and with all the other kids I will be incorporating I am looking for a faster plane to push my limits, but in this there will be a trial and error sort of situation on many levels given my current experience as a builder and a pilot. I am sure however this P-40 turns out it will blow my mind on the maiden and i will be looking to improve upon it in future builds.

I really appreciate all your feedback and feel free to add or correct at anytime. I am really getting excited about this plane, which is the devil in itself. I just want to have it built already and fly it, but i also want to take my time and do it right. Internal conflicts!!

 

[Sero]

Haha as much as you strive to make things easier and understandable, it also gets more difficult to make choices lol. All things considered it will end up to what happens in the moment of the build. I would like to build a speed wing and with all the other kids I will be incorporating I am looking for a faster plane to push my limits, but in this there will be a trial and error sort of situation on many levels given my current experience as a builder and a pilot. I am sure however this P-40 turns out it will blow my mind on the maiden and i will be looking to improve upon it in future builds.

I really appreciate all your feedback and feel free to add or correct at anytime. I am really getting excited about this plane, which is the devil in itself. I just want to have it built already and fly it, but i also want to take my time and do it right. Internal conflicts!!

So many options eh? That's the beauty of FB planes, easy to experiment with. If you build a speed wing like Nerdnick you will find its very durable and structurally sound enough to avoid flutter with a sharp TE.

 

[BATTLEAXE]

So many options eh? That's the beauty of FB planes, easy to experiment with. If you build a speed wing like Nerdnick you will find its very durable and structurally sound enough to avoid flutter with a sharp TE.

Yea I don't think my motor will be takin it to 100 mph, maybe 100 kph, and at that point I might get flutter in the tail feathers but it will be a rush for me. And if I acquire a bigger motor and the plane isn't smashed to pieces I'll put it to the test. If it needs improvements, it's FB, build a new one. Or a different model. Thanks for your feedback and keep following, chime in whenever you feel the desire. Some times the best answers come from questions that aren't asked.

 

[Hai-Lee]

Yea I don't think my motor will be takin it to 100 mph, maybe 100 kph, and at that point I might get flutter in the tail feathers but it will be a rush for me. And if I acquire a bigger motor and the plane isn't smashed to pieces I'll put it to the test. If it needs improvements, it's FB, build a new one. Or a different model. Thanks for your feedback and keep following, chime in whenever you feel the desire. Some times the best answers come from questions that aren't asked.

Ok I mentioned the aerodynamic concerns in avoiding flutter now I will add to the issue with a file concerning control surface design, (low level with no maths), for those wanting to chase those higher speeds.

The file gives some idea of what should be looked for or implemented to reduce the possibility of flutter becoming part of the design!


Have fun!

 

[BATTLEAXE]

Ok I mentioned the aerodynamic concerns in avoiding flutter now I will add to the issue with a file concerning control surface design, (low level with no maths), for those wanting to chase those higher speeds.

The file gives some idea of what should be looked for or implemented to reduce the possibility of flutter becoming part of the design!


Have fun!

Wow you gave me a lot to read over. Is there a test later lol?! I have a post coming up soon here of the right wing I built this afternoon, If you have any thoughts or concerns pls let me know. Thanks for the info

 

[BATTLEAXE]

So this is my first attempt at a speed wing and I have a mountain of advice to choose from and guide me. The results, I am way more impressed then the first wing and in some ways it was actually a little easier to make. You tell me what you think:

Don't mind the mess on the bench lol. This is what I came up with as a plan. I was goin to try to measure and draw out a mirror image of the bottom panel from the top on both wings but that was goin to take a lot of time and leave a lot of room for error, so I cut off the bottom plate from both wing plans and taped the two top halves together. With this one sheet I can make both wings and like mentioned by @Sero in a previous post, I can trim off what I don't need from the bottom plate after the wing is folded and glued. I took the paper off the front half and 1" in around the outside of the top plate. I bevel cut the LE on both the bottom and top and sanded down a taper around the outer edge where the paper was removed to about just less then 1mm at the edge feathered to full thickness at the paper left in the middle of the panel. Installed the original spar and placed my aileron servo in its original location, but this time instead of placing it directly on top of the paper inside, I traced out the shape of the servo and used the hot glue gun tip to melt halfway into the foam to make a slight depression for room. I glued the spar, LE and tail edge of the top plate and folded it over leaving the wing tip open. Once cooled I moved over to the tip, squeezed a bead of glue in and carefully with the palm of my hand evenly pressed on the top panel of the tip to close it up. The cool part is that the top panel at the TE was 1/4 inch shorter then the bottom panel so i carefully trimmed it even with the top to make a clean straight edge. Then sanded it smooth and shaped up the wing tips to match bottom to top.

I couldn't resist cleaning it up a little with the iron...

And here is the profile...

The bottom is flat, clean and continuous front to back. I still have to cut in the ailerons and flaps. But this was really easy to do and I am thinking It could be done on any of the wings for the FT models. In fact I don't know if I will be doing the original wing folds again, This is way more rewarding to build and to tell you the truth just as easy or if not easier. Thanks for reading and give me your feedback.

 

[Hai-Lee]

So this is my first attempt at a speed wing and I have a mountain of advice to choose from and guide me. The results, I am way more impressed then the first wing and in some ways it was actually a little easier to make. You tell me what you think:
View attachment 142080
Don't mind the mess on the bench lol. This is what I came up with as a plan. I was goin to try to measure and draw out a mirror image of the bottom panel from the top on both wings but that was goin to take a lot of time and leave a lot of room for error, so I cut off the bottom plate from both wing plans and taped the two top halves together. With this one sheet I can make both wings and like mentioned by @Sero in a previous post, I can trim off what I don't need from the bottom plate after the wing is folded and glued. I took the paper off the front half and 1" in around the outside of the top plate. I bevel cut the LE on both the bottom and top and sanded down a taper around the outer edge where the paper was removed to about just less then 1mm at the edge feathered to full thickness at the paper left in the middle of the panel. Installed the original spar and placed my aileron servo in its original location, but this time instead of placing it directly on top of the paper inside, I traced out the shape of the servo and used the hot glue gun tip to melt halfway into the foam to make a slight depression for room. I glued the spar, LE and tail edge of the top plate and folded it over leaving the wing tip open. Once cooled I moved over to the tip, squeezed a bead of glue in and carefully with the palm of my hand evenly pressed on the top panel of the tip to close it up. The cool part is that the top panel at the TE was 1/4 inch shorter then the bottom panel so i carefully trimmed it even with the top to make a clean straight edge. Then sanded it smooth and shaped up the wing tips to match bottom to top.
View attachment 142082 View attachment 142083 View attachment 142085
I couldn't resist cleaning it up a little with the iron... View attachment 142084
And here is the profile...
View attachment 142081
The bottom is flat, clean and continuous front to back. I still have to cut in the ailerons and flaps. But this was really easy to do and I am thinking It could be done on any of the wings for the FT models. In fact I don't know if I will be doing the original wing folds again, This is way more rewarding to build and to tell you the truth just as easy or if not easier. Thanks for reading and give me your feedback.

Just one thing on a structural point!.

Whilst the folds do make the wing look less than perfect they do provide a great deal of strength to the equation. When you remove the folds you can actually make the stricture weaker and less able to withstand torsion or twisting forces! The spar you have added is a little too far rearwards IMO. In fact the spar is best located at the balance pint for the design. To regain some of the torsional resistance I would add a couple of additional sub spars using FB without any paper. These sub spars would be about half or a little more of the span of each wing starting at the centre of the joined wings.

You need not change the wing design at this time bit as you attempt to go faster the forces acting upon the wing could become rather high and IF the bird does become uncontrollable or unstable at high speed just try to remember next time to not only prevent the wing from folding but also to try to prevent the wing from twisting either nose up or nose down in flight!

Just my opinion of course!

Have fun!

 

[Sero]

You did a fine job!
I do agree you will have lost some structural strength, but if your not running too much power, which I believe you said, I wouldn't worry about it. You could add some packing tape to the bottom of the wing when both halves are glued together or perhaps even add a wood spar to your existing wing. Just put glue on and slide it into place. That will only work if you have no dihedral of course.
In the last photo the spar looks too far back but in the second photo it looks ok to me.
Also when you cut the ailerons you may cut into an area that you haven't glued and the top and bottom may seperate, so be ready with the glue gun.

 

[BATTLEAXE]

Just one thing on a structural point!.

Whilst the folds do make the wing look less than perfect they do provide a great deal of strength to the equation. When you remove the folds you can actually make the stricture weaker and less able to withstand torsion or twisting forces! The spar you have added is a little too far rearwards IMO. In fact the spar is best located at the balance pint for the design. To regain some of the torsional resistance I would add a couple of additional sub spars using FB without any paper. These sub spars would be about half or a little more of the span of each wing starting at the centre of the joined wings.

You need not change the wing design at this time bit as you attempt to go faster the forces acting upon the wing could become rather high and IF the bird does become uncontrollable or unstable at high speed just try to remember next time to not only prevent the wing from folding but also to try to prevent the wing from twisting either nose up or nose down in flight!

Just my opinion of course!

Have fun!

You did a fine job!
I do agree you will have lost some structural strength, but if your not running too much power, which I believe you said, I wouldn't worry about it. You could add some packing tape to the bottom of the wing when both halves are glued together or perhaps even add a wood spar to your existing wing. Just put glue on and slide it into place. That will only work if you have no dihedral of course.
In the last photo the spar looks too far back but in the second photo it looks ok to me.
Also when you cut the ailerons you may cut into an area that you haven't glued and the top and bottom may seperate, so be ready with the glue gun.

HAHA, I love it. I am way ahead of you guys and i knew you would say something about it... I am actually smiling right now. The spar that is in the pics is in the original position as the folded wing. Right after I posted this i went back to the bench and played with the wing foil in front of the spar and i noticed that because of not having folds or the paper on the inside, the area ahead of the spar was kinda spongy. So fabricated a slide in double thick vertical spar to fit 1.5" ahead of the original. The wing now has 2 spars that reach 12" in the LE and connect at the center. I was worried about the wing changing shape but the strength thing is taken care of as well. Yes there is some dihedral but not as much as the original design. I like not having it but in the nature of the design of the P-40 I still added some.

You will notice that i didn't put in the flap servos as well. I am not to sure how to set up the servos for flaps. I have done it once before on one of my first planes but I also had the servos accessible from the outside so i could move the arms as needed. I would have liked to have them hidden in the wing but i will install them on the outside pointing down. I have built the left wing and put them together and it is still accessible to feed the wires.

@Hai-Lee what do you think of the TE and how it is shaped?

Thanks for reading

 

[Hai-Lee]

HAHA, I love it. I am way ahead of you guys and i knew you would say something about it... I am actually smiling right now. The spar that is in the pics is in the original position as the folded wing. Right after I posted this i went back to the bench and played with the wing foil in front of the spar and i noticed that because of not having folds or the paper on the inside, the area ahead of the spar was kinda spongy. So fabricated a slide in double thick vertical spar to fit 1.5" ahead of the original. The wing now has 2 spars that reach 12" in the LE and connect at the center. I was worried about the wing changing shape but the strength thing is taken care of as well. Yes there is some dihedral but not as much as the original design. I like not having it but in the nature of the design of the P-40 I still added some.

You will notice that i didn't put in the flap servos as well. I am not to sure how to set up the servos for flaps. I have done it once before on one of my first planes but I also had the servos accessible from the outside so i could move the arms as needed. I would have liked to have them hidden in the wing but i will install them on the outside pointing down. I have built the left wing and put them together and it is still accessible to feed the wires.

@Hai-Lee what do you think of the TE and how it is shaped?

Thanks for reading

The TE looks OK but be aware that when you cut in the ailerons/flaps you will need to fill the voids in the wings and the control surfaces with scrap foam in order to maintain their shape long term.

When doing such a wing I prefer to have the control surfaces part of the top wing surface, (or part of the bottom where the hinge is open on the wing upper surface). I use a broad bevel/taper on the short wing panel so that the bottom wing panel is only paper thick at its most rearwards edge. I glue this tapered section to the other wing panel so that the edges of the paper lines up with the hinge line. As for the treatment of the single layer of FB that makes up the control surface I have ironed them and even used thin balsa reinforcing for added strength. Remember that on a high speed model you do not require much control surface deflection at high speed, or you can use smaller control surfaces, (shorter cord, full span).

Whatever you do make sure that it is light and strong and such that the control surface cannot be inflated or deflated, (have its shape altered), by high or low pressure air.

Have fun!

 

[BATTLEAXE]

The TE looks OK but be aware that when you cut in the ailerons/flaps you will need to fill the voids in the wings and the control surfaces with scrap foam in order to maintain their shape long term.

When doing such a wing I prefer to have the control surfaces part of the top wing surface, (or part of the bottom where the hinge is open on the wing upper surface). I use a broad bevel/taper on the short wing panel so that the bottom wing panel is only paper thick at its most rearwards edge. I glue this tapered section to the other wing panel so that the edges of the paper lines up with the hinge line. As for the treatment of the single layer of FB that makes up the control surface I have ironed them and even used thin balsa reinforcing for added strength. Remember that on a high speed model you do not require much control surface deflection at high speed, or you can use smaller control surfaces, (shorter cord, full span).

Whatever you do make sure that it is light and strong and such that the control surface cannot be inflated or deflated, (have its shape altered), by high or low pressure air.

Have fun!

Thanks for the heads up. I do believe that when I do open it up there will be a void. I have yet t work out how I am going to do the hinge. I will know better once I cut into it. I think I like the balsa idea, we will see. Thanks for the feedback

 

[bracesport]

@BATTLEAXE - simple to fix think about what I did with the DLG wing - you can just scale up that idea and add a middle foam section tapered to fill the void under the top skin - easy peasy!

 

[BATTLEAXE]

I he

@BATTLEAXE - simple to fix think about what I did with the DLG wing - you can just scale up that idea and add a middle foam section tapered to fill the void under the top skin - easy peasy!

It should be easy to compensate for but i dont know exsactly what i am dealing with until i install the wing thru the fuse and cut into the wing. I have an idea worked out in my brain box that may be a surprise for you all if it works out. I imagine i will have to fill a void.

I am so impressed with the wing though. If it flies well i will be building wings like this from now on. Good fungshua 😁👍😉