markvanhaze
Member
I always loved Spitfires and when David released his foamboard version, I went straight away and ordered the speed build kit which including shipping to Europe cost far and beyond ridiculous. But once I built it (my first foamboard plane ever), that thing flew like a dream and I think to this day it is probably the plane I flew the most in my 2 year RC career.
A few weeks back I was at a club watching a guy fly a traditional balsa Messerschmitt Bf 109. It was a 160cm wingspan nitro converted to electric and that thing went like a rocket! Best of all, when he came down into a solid dive, full throttle, he would level out just above our heads and cut the throttle which would make an incredible sound, something between a Harley Davidson starting sound and a wolf sneezing (the best I can do to describe that awesome sound). So I went up to the guy and asked him what he had inside, and noted down the prop, engine and lipo combo.
Back home there was no question for me - my FT Spitfire had a broken wing spar and rather than fixing it, I was going to make a big ass Spitfire with exactly those parts - so effectively I ended up planning the FT Spitfire around a 600KV motor.
Just about that time I left a voice message for the podcast asking whether there were any plans to release bigger versions of the FT planes and since that was just before the 400th episode, the guys spilled the beans that they were doing 200% versions.
Now patience is not my thing so I just went ahead and printed a 150% version of the plan, guessing my way along the way.
All my foamboard sheets are of course too small so what I do is lay the plans over the board and try to find places for the joints where it will be easy to put the front and back together. In the photo you can see that the fuselage is cut at the tail section and the wings are cut into 3 parts. Then join the sheets using tape and hot glue (tape on side, hot glue along the edge then wipe off the excess).
I re-enforced pretty much every bend with fiber tape too.
The one thing I was worried about was the wing spar and even on the small Spitfire with the beefy Lazertoys motor, the spar eventually broke while doing an inverted loop. So I decided to make a really solid spar for the wing.
I tried to copy the shape and angle of the foam spar and then test fitted it in the wing:
It turns out that the angle of the wing halves was massive and resulted in a crazy dihedral. So after fiddling around for an hour, I changed the spar and measured it:
At 55mm off the table, I get a 9 degree dihedral which is closer to the 10 degrees on the regular FT Spitfire. Now you might think all that messing around with the spar is not worth it but if you have been watching the 400th episode on Flitetest then you know what happened to Davids 200% Spitfire. Foam spars = no-no (for big planes).
Next it was time to glue the servos in and since this is a big plane, I got big servos - 9 gram won't do here.
I always check the servos with a servo tester because once you close that wing (which is a pain in the behind) then you won't want to be stuck with a dodgy servo. You will also need to extend the servo cables - I didn't have extensions so it was time to bring out the soldering iron.
Time to close up the wing and use plenty of fiber tape to re-enforce everything, especially the hinges. Note: If you suck at cutting bevels and marvel at Josh doing it in one easy swoop - give up, use tape.
Next I started cutting out and joining the fuselage. Just like David, I decided to make a box that would strengthen the fuselage and also become an extension for the motor box.
Doubling the stabilizer and the elevator sounds easier than it actually was. A Good tip here is to tape the hinges, and then stick the surfaces together with the bevels facing outwards and the taped hinges facing each other.
When cutting out the holes for the tail servos, double check that you place them far enough apart since the cut out holes for the 9 gram servos wont work.
The stabilizer was another tricky bit - it would not fit since everything was double the width.
I ended up having to enlarge the hole for the elevator so it could move freely and also re-cutting the slots for the stabilizer. Apart from that though all is pretty much the same and with plenty of hot glue it sat nicely between the fuselage walls.
Next it was time to make the motor box. Since this was a massive engine, that had to be made of plywood.
My wood skills are hoooooorrible at best and the box turned out to be more of a trapezoid but once it was all Gorilla glued, it had to do. The big holes are not for saving weight - they make fiddling with wires and the lipos easier, once its all inside the fuselage. Also, when you mount the motor, use washers to make it it point slightly down and to the right. This will help to counter the torque of the motor. Just make sure the axle is still pointing into the middle of your box.
Now I joined the foamboard box with the wood box and by using the extensions that are holding the corners of the wooden box together, I glued the foamboard onto it.
It was about there when I realized that the fuselage might be a bit flimsy when compared to the front part and so I decided to strengthen that with another sheet of foamboard.
Now it was time to look at how I was going to attach the wings. I cut out the bottom part of the fuselage since this was going to have to be a removable wing. There I had to cut plywood walls to strengthen where the plane would end up sitting when the wings were not attached. These walls were also useful for the mega BBQ skewers
since they gave them a solid support wall. I also tripled all the contact surfaces so that the wing would not get dented to badly once it was attached with rubber bands.
Now I had to balance the plane and using the wing spar line found out that even with such a beats of a motor, 2 x 3000mah 3S and all the wood, the Spitfire was tail heavy. Obviously I was too thorough with the tail strengthening and the heavy servos so I ended up adding some lead weight in order to get it balanced for a test flight.
Currently the 2 x 3000mah 3S lipos are all I have so I will look into replacing them with bigger batteries so that I can get rid of the lead weights and get more flying time.
I attached a 11 x 7 prop and the watt meter showed me around 500Watts which was not bad but I since I had a bigger one lying around too, I tried the 12x6 prop. Now we were pulling around 1000Watts - that's more like it!
Ok so with a receiver installed and the ESC (60Amp Turnigy Plush) temporarily taped to the nose, I was off to fly the beast.
And did it fly? Hell yeah - this thing rocks! What really took me by surprise is that I could glide that plane with zero throttle as if it was a glider. It has unlimited vertical and can still turn on a dime - fantastic. So then the question was - would it make the noise, you know, the Harley Davidson starting wolf sneeze? Well I had 2 flights only (flight time is around 9 mins.) and on the second flight I dared to give it that massive dive and kill the throttle on leveling out. The sound is there, no doubt, but it sounds a bit weaker. I will try an even bigger prop soon and add the spinner which might affect that sound, we shall see and a video is coming too.
Now i'm off to find a solution for making the top part of the plane, ideally in a way that allows me to access the batteries easily. Stay tuned and feel free to ask any questions.
A few weeks back I was at a club watching a guy fly a traditional balsa Messerschmitt Bf 109. It was a 160cm wingspan nitro converted to electric and that thing went like a rocket! Best of all, when he came down into a solid dive, full throttle, he would level out just above our heads and cut the throttle which would make an incredible sound, something between a Harley Davidson starting sound and a wolf sneezing (the best I can do to describe that awesome sound). So I went up to the guy and asked him what he had inside, and noted down the prop, engine and lipo combo.
Back home there was no question for me - my FT Spitfire had a broken wing spar and rather than fixing it, I was going to make a big ass Spitfire with exactly those parts - so effectively I ended up planning the FT Spitfire around a 600KV motor.
Just about that time I left a voice message for the podcast asking whether there were any plans to release bigger versions of the FT planes and since that was just before the 400th episode, the guys spilled the beans that they were doing 200% versions.
Now patience is not my thing so I just went ahead and printed a 150% version of the plan, guessing my way along the way.
All my foamboard sheets are of course too small so what I do is lay the plans over the board and try to find places for the joints where it will be easy to put the front and back together. In the photo you can see that the fuselage is cut at the tail section and the wings are cut into 3 parts. Then join the sheets using tape and hot glue (tape on side, hot glue along the edge then wipe off the excess).
I re-enforced pretty much every bend with fiber tape too.
The one thing I was worried about was the wing spar and even on the small Spitfire with the beefy Lazertoys motor, the spar eventually broke while doing an inverted loop. So I decided to make a really solid spar for the wing.
I tried to copy the shape and angle of the foam spar and then test fitted it in the wing:
It turns out that the angle of the wing halves was massive and resulted in a crazy dihedral. So after fiddling around for an hour, I changed the spar and measured it:
At 55mm off the table, I get a 9 degree dihedral which is closer to the 10 degrees on the regular FT Spitfire. Now you might think all that messing around with the spar is not worth it but if you have been watching the 400th episode on Flitetest then you know what happened to Davids 200% Spitfire. Foam spars = no-no (for big planes).
Next it was time to glue the servos in and since this is a big plane, I got big servos - 9 gram won't do here.
I always check the servos with a servo tester because once you close that wing (which is a pain in the behind) then you won't want to be stuck with a dodgy servo. You will also need to extend the servo cables - I didn't have extensions so it was time to bring out the soldering iron.
Time to close up the wing and use plenty of fiber tape to re-enforce everything, especially the hinges. Note: If you suck at cutting bevels and marvel at Josh doing it in one easy swoop - give up, use tape.
Next I started cutting out and joining the fuselage. Just like David, I decided to make a box that would strengthen the fuselage and also become an extension for the motor box.
Doubling the stabilizer and the elevator sounds easier than it actually was. A Good tip here is to tape the hinges, and then stick the surfaces together with the bevels facing outwards and the taped hinges facing each other.
When cutting out the holes for the tail servos, double check that you place them far enough apart since the cut out holes for the 9 gram servos wont work.
The stabilizer was another tricky bit - it would not fit since everything was double the width.
I ended up having to enlarge the hole for the elevator so it could move freely and also re-cutting the slots for the stabilizer. Apart from that though all is pretty much the same and with plenty of hot glue it sat nicely between the fuselage walls.
Next it was time to make the motor box. Since this was a massive engine, that had to be made of plywood.
My wood skills are hoooooorrible at best and the box turned out to be more of a trapezoid but once it was all Gorilla glued, it had to do. The big holes are not for saving weight - they make fiddling with wires and the lipos easier, once its all inside the fuselage. Also, when you mount the motor, use washers to make it it point slightly down and to the right. This will help to counter the torque of the motor. Just make sure the axle is still pointing into the middle of your box.
Now I joined the foamboard box with the wood box and by using the extensions that are holding the corners of the wooden box together, I glued the foamboard onto it.
It was about there when I realized that the fuselage might be a bit flimsy when compared to the front part and so I decided to strengthen that with another sheet of foamboard.
Now it was time to look at how I was going to attach the wings. I cut out the bottom part of the fuselage since this was going to have to be a removable wing. There I had to cut plywood walls to strengthen where the plane would end up sitting when the wings were not attached. These walls were also useful for the mega BBQ skewers
since they gave them a solid support wall. I also tripled all the contact surfaces so that the wing would not get dented to badly once it was attached with rubber bands.
Now I had to balance the plane and using the wing spar line found out that even with such a beats of a motor, 2 x 3000mah 3S and all the wood, the Spitfire was tail heavy. Obviously I was too thorough with the tail strengthening and the heavy servos so I ended up adding some lead weight in order to get it balanced for a test flight.
Currently the 2 x 3000mah 3S lipos are all I have so I will look into replacing them with bigger batteries so that I can get rid of the lead weights and get more flying time.
I attached a 11 x 7 prop and the watt meter showed me around 500Watts which was not bad but I since I had a bigger one lying around too, I tried the 12x6 prop. Now we were pulling around 1000Watts - that's more like it!
Ok so with a receiver installed and the ESC (60Amp Turnigy Plush) temporarily taped to the nose, I was off to fly the beast.
And did it fly? Hell yeah - this thing rocks! What really took me by surprise is that I could glide that plane with zero throttle as if it was a glider. It has unlimited vertical and can still turn on a dime - fantastic. So then the question was - would it make the noise, you know, the Harley Davidson starting wolf sneeze? Well I had 2 flights only (flight time is around 9 mins.) and on the second flight I dared to give it that massive dive and kill the throttle on leveling out. The sound is there, no doubt, but it sounds a bit weaker. I will try an even bigger prop soon and add the spinner which might affect that sound, we shall see and a video is coming too.
Now i'm off to find a solution for making the top part of the plane, ideally in a way that allows me to access the batteries easily. Stay tuned and feel free to ask any questions.
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