RacerX
Member
Winter is here! And the "here" is Ohio! Insert appropriate cuss word. I prefer flibbatteefloo.
I started on this last Saturday morning. Drew up the plans a week before that and I finished the build last night.
I really like the styling of the Pitts biplane, so I thought I'd try to make something similar. I also like the 750mm wingspan size which is right around 30". It makes for a nice size to transport but still gives a decent scale for keeping orientation in the air.
I named this plane Fitts. I'm hoping it doesn't give me fits when flying.
(added the plans in PDF format)
View attachment FittsPlans1.pdf
View attachment FittsPlans2.pdf
One thing I'm not sure about is that I only put the ailerons on the lower wing. I didn't do corresponding ailerons on the upper. I did make the ailerons oversize to hopefully gain some authority. If it doesn't fly well, I could always cut in upper ailerons and link them together.
One other change, to the original scale design, is a larger rudder. I also made two changes (one was a mistake) during the build process. First, I mounted the landing gear farther back than the scale location. It seemed like a good idea to have it mounted right at the front of the lower wing for good support. The landing gear location might make it tend to nose-over during landings. The bigger mistake was when I mounted the upper wing. I centered it on the upright struts which shifts it more forward than an actual Pitts. Will the accentuated "stagger" make it fly worse? I'll have to find out when I maiden it.
I don't try to build as "swappable." I've decided that for my purposes, I would rather dedicate the electronics to each plane I build. That and it makes it a tiny bit lighter because I don't have the extra foam board for the power pod.
I made this out of standard Dollar Tree foam board and wrap all of the parts with clear shipping tape for durability.
Notes on the design:
- 3/16" wood dowels in the wings for spars
- barbecue skewers shoved through the foam board upright wing struts
- bottom of fuselage left open to reduce weight
- CG is a bit tricky and I'll have to see how it flies
- had to mount the battery right behind the firewall to get where I think CG should be
- I didn't separate the aileron servos for flaperons (might do that later)
- I laminated a second layer of foam board on each wing to create a KF airfoil
- the fuselage is a bit wider than scale - I wanted it to be pudgy, go figure
- I may put a smaller prop on it, once I maiden it, just to get longer flight time
- no plan for a canopy - easy access to everything
Here's the CAD view of the profile and the Pitts photo that I used to trace the basic shape.
Here's the printed full size plans for all of the parts.
Here are some photos at different stages of the build.
Here's the completed plane.
Added a couple of closeups of the fuselage showing the upper wing attachment and the placement of the elevator and rudder servos.
And here's why I won't be showing a maiden flight video for a while. (taken about an hour before I posted this thread)
I used fishing line for the wire reinforcing between the wings. The firewall is a plastic tray from a 2.5" SSD - I get a lot of those from work.
Here's the specs:
- 30" wingspan (approximately)
- 671 grams flying weight with revised landing gear (measured)
- EMax CF2215 1200kv brushless
- HobbyWing 30A ESC
- 1300mah 3s LiPo
- LemonRX DSMX receiver with stabilizer
- 10x4.5 GWS style slow fly prop
- EMax 9g analog servos
- 21.2A draw at WOT (measured)
- 823 grams thrust (measured)
Here's a photo of what the AUW (flying weight) is now that I revised the landing gear location. Thanks to jamboree1 for the advice on that.
I started on this last Saturday morning. Drew up the plans a week before that and I finished the build last night.
I really like the styling of the Pitts biplane, so I thought I'd try to make something similar. I also like the 750mm wingspan size which is right around 30". It makes for a nice size to transport but still gives a decent scale for keeping orientation in the air.
I named this plane Fitts. I'm hoping it doesn't give me fits when flying.
(added the plans in PDF format)
View attachment FittsPlans1.pdf
View attachment FittsPlans2.pdf
One thing I'm not sure about is that I only put the ailerons on the lower wing. I didn't do corresponding ailerons on the upper. I did make the ailerons oversize to hopefully gain some authority. If it doesn't fly well, I could always cut in upper ailerons and link them together.
One other change, to the original scale design, is a larger rudder. I also made two changes (one was a mistake) during the build process. First, I mounted the landing gear farther back than the scale location. It seemed like a good idea to have it mounted right at the front of the lower wing for good support. The landing gear location might make it tend to nose-over during landings. The bigger mistake was when I mounted the upper wing. I centered it on the upright struts which shifts it more forward than an actual Pitts. Will the accentuated "stagger" make it fly worse? I'll have to find out when I maiden it.
I don't try to build as "swappable." I've decided that for my purposes, I would rather dedicate the electronics to each plane I build. That and it makes it a tiny bit lighter because I don't have the extra foam board for the power pod.
I made this out of standard Dollar Tree foam board and wrap all of the parts with clear shipping tape for durability.
Notes on the design:
- 3/16" wood dowels in the wings for spars
- barbecue skewers shoved through the foam board upright wing struts
- bottom of fuselage left open to reduce weight
- CG is a bit tricky and I'll have to see how it flies
- had to mount the battery right behind the firewall to get where I think CG should be
- I didn't separate the aileron servos for flaperons (might do that later)
- I laminated a second layer of foam board on each wing to create a KF airfoil
- the fuselage is a bit wider than scale - I wanted it to be pudgy, go figure
- I may put a smaller prop on it, once I maiden it, just to get longer flight time
- no plan for a canopy - easy access to everything
Here's the CAD view of the profile and the Pitts photo that I used to trace the basic shape.
Here's the printed full size plans for all of the parts.
Here are some photos at different stages of the build.
Here's the completed plane.
Added a couple of closeups of the fuselage showing the upper wing attachment and the placement of the elevator and rudder servos.
And here's why I won't be showing a maiden flight video for a while. (taken about an hour before I posted this thread)
I used fishing line for the wire reinforcing between the wings. The firewall is a plastic tray from a 2.5" SSD - I get a lot of those from work.
Here's the specs:
- 30" wingspan (approximately)
- 671 grams flying weight with revised landing gear (measured)
- EMax CF2215 1200kv brushless
- HobbyWing 30A ESC
- 1300mah 3s LiPo
- LemonRX DSMX receiver with stabilizer
- 10x4.5 GWS style slow fly prop
- EMax 9g analog servos
- 21.2A draw at WOT (measured)
- 823 grams thrust (measured)
Here's a photo of what the AUW (flying weight) is now that I revised the landing gear location. Thanks to jamboree1 for the advice on that.
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