The Hitherto Unnamed Profile 3D Foamy (Inc. Plans)

[Pieliker96]

Here's a quick little afternoon build I did to procrastinate on a larger project. It's built from a single sheet of DTFB, runs on Power Pack A, and is designed for Aerobatic/3D Flight. It uses a KFm-2 aerofoil. It's got a thrust-to-weight of 1.85, a wing loading of 6.1 oz/sq. ft, and a cube loading of 6.3. Its all-up weight is only 166g - well under the 250g above which registration becomes a requirement. Flight times with a 450mah 2s are around 4 minutes of mixed flying, which can easily be stretched to 5 or 6 while not performing high-throttle post-stall stuff. To increase the fun factor, I'd recommend getting multiple batteries as they're plenty cheap (I paid $35 for 4 Tattu batteries).

Plans (v1.4)

I found its flight characteristics to be what I expect of this type of plane, and then some. It has plenty of power and maneuverability. It can do flat turns with no aileron input and has very little cross-control coupling. With a little bit of down and right thrust (which must be built in), It requires little trimming. It maintains attitude well within its broad flight envelope, even if it gets bumped around by wind. Any unintentional stalls or other inadvertent hairy situations can be powered out of by liberal application of throttle. The one thing I might change is to add elevator counterbalances to give a bit more pitch control at low speeds. That, and some VGs and tip plates to see if they improve high-alpha a bit.

(Slightly overexposed) Flight video with a subpar landing:

 

[Bignose703]

View attachment 174503

Here's a quick little afternoon build I did to procrastinate on a larger project. It's built from a single sheet of DTFB, runs on Power Pack A, and is designed for Aerobatic/3D Flight. It uses a KFm-2 aerofoil. It's got a thrust-to-weight of 1.85, a wing loading of 6.1 oz/sq. ft, and a cube loading of 6.3. Its all-up weight is only 166g - well under the 250g above which registration becomes a requirement. Flight times with a 450mah 2s are around 4 minutes of mixed flying, which can easily be stretched to 5 or 6 while not performing high-throttle post-stall stuff. To increase the fun factor, I'd recommend getting multiple batteries as they're plenty cheap (I paid $35 for 4 Tattu batteries).

Plans

I found its flight characteristics to be what I expect of this type of plane, and then some. It has plenty of power and maneuverability. It can do flat turns with no aileron input and has very little cross-control coupling. With a little bit of down and right thrust (which must be built in), It requires little trimming. It maintains attitude well within its broad flight envelope, even if it gets bumped around by wind. Any unintentional stalls or other inadvertent hairy situations can be powered out of by liberal application of throttle. The one thing I might change is to add elevator counterbalances to give a bit more pitch control at low speeds. That, and some VGs and tip plates to see if they improve high-alpha a bit.

(Slightly overexposed) Flight video with a subpar landing:

That’s almost exactly what I was thinking of. How do you mount the battery to the fuselage?

 

[Pieliker96]

That’s almost exactly what I was thinking of. How do you mount the battery to the fuselage?

Just some velcro on the underside.

 

[Dazzy]

@Pieliker96 , you mention plans is there a link or did I misread?
Darryl

 

[Pieliker96]

@Pieliker96 , you mention plans is there a link or did I misread?
Darryl

Yep! It's the big ole link in the very middle of the post.

 

[Dazzy]

Thanks mate for the quick reply, all good now.
Darryl

 

[Pieliker96]

I've updated the plans. Of note:
-PDF Plans are now available in tiled, A (Letter) Size, and B (Tabloid) Size!
-All control surfaces have been slightly enlarged and counterbalances added to the elevator
-More clearance has been made in the tail section for higher rudder and elevator deflections
-Thrust angle (both right and down) has been built into the plans

CLICK HERE FOR PLANS!

I modified the existing plane to the same specs as the current plans. The elevator counterbalances and increased throw allow it to do rapid pitch rate maneuvers such as crankshafts with ease.

I've also had time to identify the weak points in the design. The firewall unglued itself over time due to the Florida heat and running the motor hot. This was solved by taping the firewall to the plane in addition to gluing it. After a couple of cartwheels, the fuselage started to crinkle and crack at the aileron hinge and tail-wing glue joint, which was expected. This can easily be remedied by taping the joints to keep the empennage from flexing too far side-to-side, though a carbon fiber rod or skewer, inset into the fuselage, spanning the joint, would be a more permanent solution. I'm overall happy with the durability of the plane as it was built light to fly, not to crash.

 

[Pieliker96]

I've finally worn out the first airframe to where I'll have to rebuild it - One too many inverted pulls led to the wings partially folding. It still flew fine upright since the bottom of the wing, continuous paper, was loaded in tension - but when inverted, the interface between the fuselage and upper wing skin (glue and tape) failed and allowed the wing to flex. I put the remaining half of my pack through it with the wing in this condition, trying to get it to fail catastrophically with full-speed inverted dives and rapid elevator inputs, but no luck - it just refuses to die



Since the last update I also made a more permanent way of attaching the firewall and swapped out my old MT1806 for the FT radial one since it had degraded from continuous abuse and neglect and would no longer produce full power. The radial version seems to be running a lot cooler which bodes well for its lifespan.

I'll be revising the plans soon to include this addition and to make the design more durable without adding much more weight.

 

[Bignose703]

I've finally worn out the first airframe to where I'll have to rebuild it - One too many inverted pulls led to the wings partially folding. It still flew fine upright since the bottom of the wing, continuous paper, was loaded in tension - but when inverted, the interface between the fuselage and upper wing skin (glue and tape) failed and allowed the wing to flex. I put the remaining half of my pack through it with the wing in this condition, trying to get it to fail catastrophically with full-speed inverted dives and rapid elevator inputs, but no luck - it just refuses to die

View attachment 192339

Since the last update I also made a more permanent way of attaching the firewall and swapped out my old MT1806 for the FT radial one since it had degraded from continuous abuse and neglect and would no longer produce full power. The radial version seems to be running a lot cooler which bodes well for its lifespan.

I'll be revising the plans soon to include this addition and to make the design more durable without adding much more weight.

When I built this I had the wing folding issue, I got a dowel from the store and ran it the length of the leading edge of the wing. You could probably find a carbon fiber rod to decrease weight.

 

[The Hangar]

View attachment 174503

Here's a quick little afternoon build I did to procrastinate on a larger project. It's built from a single sheet of DTFB, runs on Power Pack A, and is designed for Aerobatic/3D Flight. It uses a KFm-2 aerofoil. It's got a thrust-to-weight of 1.85, a wing loading of 6.1 oz/sq. ft, and a cube loading of 6.3. Its all-up weight is only 166g - well under the 250g above which registration becomes a requirement. Flight times with a 450mah 2s are around 4 minutes of mixed flying, which can easily be stretched to 5 or 6 while not performing high-throttle post-stall stuff. To increase the fun factor, I'd recommend getting multiple batteries as they're plenty cheap (I paid $35 for 4 Tattu batteries).

Plans

I found its flight characteristics to be what I expect of this type of plane, and then some. It has plenty of power and maneuverability. It can do flat turns with no aileron input and has very little cross-control coupling. With a little bit of down and right thrust (which must be built in), It requires little trimming. It maintains attitude well within its broad flight envelope, even if it gets bumped around by wind. Any unintentional stalls or other inadvertent hairy situations can be powered out of by liberal application of throttle. The one thing I might change is to add elevator counterbalances to give a bit more pitch control at low speeds. That, and some VGs and tip plates to see if they improve high-alpha a bit.

(Slightly overexposed) Flight video with a subpar landing:

This is awesome - I need one in my hangar! Now to figure out what electronics to use...

 

[tomlogan1]

Just added to my build list. These single sheet planes keep getting better and better. Thanks for your contribution.

 

[Pieliker96]

The revised plans are done, all plans links have been updated to v1.4. Ideally, I'll be building it this weekend and will be able to post some pictures of the build process here.

v1.4 Changelog:
-Added improved firewall mount
-Doubled up empennage to wing join by extending the top fuselage plate rearwards
-Enlarged rudder
-Refined Plans

 

[tomlogan1]

Have a number of 2205 2300kv motors so I think that with a few 9 gram servos and a spare amp ESC I should be good to go. Like Hangar's Stick this is a very easy model to cut out. Only issue I had was on the leading edge on one side the paper ripped 1/2 inch when I made my first bend. Not an issue as I was planning to run a length of tape along the leading edge for both color and srength.

 

[Pieliker96]

Alright, here's some pictures to help you through the build process.


Start by cutting out the wing. If you're laser cutting from one side, you'll have to cut through the aileron hinges. If you're cutting by hand, leave the ailerons uncut until you can flip the wing over and cut them from the bottom side. For the long shallow bevels on the wing's leading edge and the KF step, I found it easy to butt the knife up against the edge of the table and run the wing past it. Now is the time to add a spar (a BBQ skewer would work fine) if you'd like - it's not necessary for flight but will improve durability in the long run and hard maneuvers. I also removed the paper from the inside of the part of the step that gets folded over, but that isn't strictly necessary. The trailing edge of the KF step can be difficult to get down (especially cleanly), I used a ruler to help along.


Next, cut out the empennage / Hstab and the upper fuselage plate. I added a small section of BBQ skewer embedded in the elevator to strengthen its crosslink. Take the empennage / Hstab and glue it so the elevator's hinge is the same orientation as the aileron's (paper side up) - the little tab will be on top. Do your best to center it up between the ailerons and keep it straight relative to the wing. Cut out the upper fuselage plate and do the bevels. This piece is what reinforces the empennage-wing join and gives a good bit of strength to the wings. Glue it down with a healthy amount of glue, with some on the sides to glue onto the KF step. After that, work on getting its bevels down-pat. In the place of a spar inside the leading edge, I opted for a decent length strip of scotch tape on the top and bottom of the wing. I expect this'll hold decently well as the previous version got by for a good while without any reinforcement whatsoever, though you should feel free to add a proper spar if you feel this isn't enough for what you'll be doing with the plane.


Cut out both parts of the fuselage. Start by gluing the lower fuselage into place: line it up by the center and front edge of the nose and the little strip between the rear servo cutouts. Install the aileron servo before installing the upper fuselage and the rest of the electronics and linkages. The receiver goes just behind the aileron servo, the battery is velcroed to the side the prop torque is trying to lift up. I used the outermost servo hole location for all servos. Previously, I had used the middle control horn location on the ailerons - I opted for the closest this time for maximum throw, as well as moving them rear of the hingeline by a couple millimeters to provide a mechanical differential aileron setup. The elevator control horn was also on the closest, I had to extend the cutout in the rudder a little to allow it to gain a higher downwards deflection. When positioning the rudder control horn, be wary of its location relative to the elevator when it is in the full up position - you'll have to mount it around an inch and a half down from the rudder counterbalance to get it out of the way of the elevator. I used the middle hole on the rudder control horn as it is limited in throw by the elevator's physical dimensions.


Next, cut out and glue up the motor mount. Glue and tape on the mini firewall and install the motor on it (BEFORE gluing it onto the plane!) with a bit of down and right thrust - this has been built into the firewall itself, the external seam on the motor mount from the 3/16" tab from the fold should be in the upper left as viewed from the plane's upright rear facing forwards.


That's about it! Set up rates, Expos, anything else you need to prior to the maiden - Here's what my config with insane rates looks like for reference.

A quick sharpie paint job and it's ready for a maiden flight! I'll report back with my findings once it's done, ideally tomorrow (today? it's past midnight )

 

[The Hangar]

Alright, here's some pictures to help you through the build process.

View attachment 193021 View attachment 193022 View attachment 193023
Start by cutting out the wing. If you're laser cutting from one side, you'll have to cut through the aileron hinges. If you're cutting by hand, leave the ailerons uncut until you can flip the wing over and cut them from the bottom side. For the long shallow bevels on the wing's leading edge and the KF step, I found it easy to butt the knife up against the edge of the table and run the wing past it. Now is the time to add a spar (a BBQ skewer would work fine) if you'd like - it's not necessary for flight but will improve durability in the long run and hard maneuvers. I also removed the paper from the inside of the part of the step that gets folded over, but that isn't strictly necessary. The trailing edge of the KF step can be difficult to get down (especially cleanly), I used a ruler to help along.

View attachment 193024 View attachment 193025 View attachment 193026
Next, cut out the empennage / Hstab and the upper fuselage plate. I added a small section of BBQ skewer embedded in the elevator to strengthen its crosslink. Take the empennage / Hstab and glue it so the elevator's hinge is the same orientation as the aileron's (paper side up) - the little tab will be on top. Do your best to center it up between the ailerons and keep it straight relative to the wing. Cut out the upper fuselage plate and do the bevels. This piece is what reinforces the empennage-wing join and gives a good bit of strength to the wings. Glue it down with a healthy amount of glue, with some on the sides to glue onto the KF step. After that, work on getting its bevels down-pat. In the place of a spar inside the leading edge, I opted for a decent length strip of scotch tape on the top and bottom of the wing. I expect this'll hold decently well as the previous version got by for a good while without any reinforcement whatsoever, though you should feel free to add a proper spar if you feel this isn't enough for what you'll be doing with the plane.

View attachment 193027 View attachment 193028 View attachment 193029 View attachment 193030
Cut out both parts of the fuselage. Start by gluing the lower fuselage into place: line it up by the center and front edge of the nose and the little strip between the rear servo cutouts. Install the aileron servo before installing the upper fuselage and the rest of the electronics and linkages. The receiver goes just behind the aileron servo, the battery is velcroed to the side the prop torque is trying to lift up. I used the outermost servo hole location for all servos. Previously, I had used the middle control horn location on the ailerons - I opted for the closest this time for maximum throw, as well as moving them rear of the hingeline by a couple millimeters to provide a mechanical differential aileron setup. The elevator control horn was also on the closest, I had to extend the cutout in the rudder a little to allow it to gain a higher downwards deflection. When positioning the rudder control horn, be wary of its location relative to the elevator when it is in the full up position - you'll have to mount it around an inch and a half down from the rudder counterbalance to get it out of the way of the elevator. I used the middle hole on the rudder control horn as it is limited in throw by the elevator's physical dimensions.

View attachment 193031 View attachment 193032
Next, cut out and glue up the motor mount. Glue and tape on the mini firewall and install the motor on it (BEFORE gluing it onto the plane!) with a bit of down and right thrust - this has been built into the firewall itself, the external seam on the motor mount from the 3/16" tab from the fold should be in the upper left as viewed from the plane's upright rear facing forwards.

View attachment 193033
That's about it! Set up rates, Expos, anything else you need to prior to the maiden - Here's what my config with insane rates looks like for reference.

A quick sharpie paint job and it's ready for a maiden flight! I'll report back with my findings once it's done, ideally tomorrow (today? it's past midnight )
View attachment 193034

Awesome! I’m still waiting on my electronics...

 

[Pieliker96]

V1.4 flight report:
-It flies about the same as the original - with the higher rates, I had to give it a bit more expo, up to 35% on all axes now.
-It can be a bit of a handful to get trimmed out since the controls are so sensitive - make sure they're all as close to centered before the maiden flight and make sure to gain a good bit of altitude before trimming out
-The added rudder and elevator area help maneuverability a good bit, it makes post-stall stuff more fun.
-It handles wind - even gusty conditions that require around 1/2 throttle to stay put - decently well. It won't inadvertently change attitude without control input - but, with such a low wing loading, it does get pushed around a good bit.