Eaglet 250 From Willy Nillies Tail Dragger Configuration

[Michael9865]

This will be my build log as I construct a tail dragger version of the Willy Nillies Eaglet 250. It has been a while since I built a balsa airplane.
My hope is to use the thread by @speedbirdted, https://forum.flitetest.com/index.php?threads/willy-nillies-eaglet-250-build.62260/, as a guide. His aircraft looked like this below.

 

[Michael9865]

Step 1 - I organized all the fuselage parts after I cut them out of the sheets. The first picture below shows the process has begun. The next picture is from the build thread by @TooJung2Die, https://forum.flitetest.com/index.p...s-eaglet-250-beta-kit-build-and-flight.61727/. I unfortunately forgot to take a picture like he did.





Step 2 - I started to layout new sub bulkheads to mount the main gear to attach to. I will use some scrap balsa to create rails and strengthen the attachment of the new main gear sub bulkheads. After cutting out the new sub bulkheads for the main landing gear, I sanded them to fit into the plywood sheet that the other plywood bulkheads came from. Then I test fitted them into the fuselage sides and got some square balsa stock cut to fit vertically for rails. Reassemble the the bulkheads and landing gear sub bulkheads to assure proper alignment.













Step 3 - Glue blind nuts into the firewall. Don’t skip this step like I did. LOL. Fit the firewall and bulkheads back to the one at the trailing edge of the wing into the fuselage sides. Glue them in place. Add bulkhead and stringer supports to tail section. Ensure that the ail is square and even. Glue in place. Add triangular shaped balsa at the rear bottom of the tail, glue in place.

 

[Michael9865]

Step 4 - I changed the bottom sheeting around to allow for the main landing gear being moved forward. I glued the sheeting part back into the sheeting to add to the length. It still needed a bit more length so I added another piece of scrap, this will become the battery hatch. I cut the nose gear plywood doubler and glued it to the inside of the sheeting piece that goes behind the main landing gear. The plywood will give the hatch latch screw a place to hold onto. I used thick thick super glue to attach a piece of dowel to the battery hatch. It will come through the bottom hole of the prepared firewall to hold the hatch in place. I then used square stock and scrap balsa th strengthen the dowel in place. Cut and glued in the fuselage doubler pieces to fit in battery compartment.



Step 5 - Top hatch and windscreen assembly is made by sanding the angle on the the lower part of the windscreen to mate up to the rest of the hatch. I also sanded the top forward part of the bulkhead at the wing leading edge to match the fuselage sides. Next I will figure out the attachment system for the top hatch and install the fuselage stringers.



Step 6 - I added the stringers to the top rear of the fuselage. I the made and installed a balsa former from scrap to help align and strengthen the forward end of the bottom rear stringers. Installed the bottom rear stringers. I added the vertical supports to the fuselage sides at the stringer support locations. I used thick thick super glue to attach a piece of dowel to the top hatch. It will come through the top hole of the prepared firewall to hold the hatch in place. I decided to go with a small rubber band/hair tie to hold the hatch in place during flight.



Step 7 - I cut out the tail feathers and all their lightening holes. That was really quick.

 

[Michael9865]

For the wing construction I am following the “Semi Symmetrical Wing Assembly” pdf from the Willy Nillies Facebook page, https://www.facebook.com/groups/2402192033374289/files/. In the fourth and eighth picture you will see how I set the center ribs with a square after propping up the wing tip to half the dihedral. In picture 10 you will see that I forgot that I was working with balsa. Doh! The webbing will add some strength. LOL!

 

[Michael9865]

Reserved for covering.

 

[Michael9865]

Reserved for final assembly and equipment installation.

 

[Michael9865]

Reserved For Proof Of Flight

 

[rockyboy]

Lots of reservations in here.

Looking forward to getting some wild nekkid balsa shots in here soon!

 

[Michael9865]

Lots of reservations in here.

Looking forward to getting some wild nekkid balsa shots in here soon!

Updated the first and second posts for your tame viewing pleasure. 😁

 

[speedbirdted]

I've seen a good amount of Eaglets built this way in the WN facebook group. I didn't think building it this way would be so popular.

A couple things I can remember being problems when I built mine is the tailwheel causing all sorts of CG problems and the battery tray size. I should have gone a lot smaller with the tailwheel - I think the wheel on it is a little over 1/2 inch diameter, when I probably could have gotten away with half that. It needed nose weight. Don't know exactly how much, I just put weight in till it balanced out right. I would suggest using a skid - when I built my Q-tee I was initially worried about it causing all sorts of problems but eventually I got the hang of it and now I never ground loop it. Just be sure to add about 1-2 degrees of toe-in on either wheel which will really help make it a lot less squirrelly on the ground.

I don't know if you'll have the battery tray problem like I did. Initially my idea was to put the ESC and receiver in the battery tray and put the battery on the top side, with a top hatch. It seemed like it would be easier to get to the battery that way, and it was until I discovered that 2s wasn't enough power and my 3s batteries didn't fit in the tray! So I had to move the ESC and receiver to the top (which is technically where they're supposed to go in the first place) Unfortunately when I added the slot for the gear it shortened the tray by about 7 mm so most of my batteries would then not fit in the actual battery tray. I have a few that that do fit, however they're no longer manufactured so once the ones I have are too worn out to be used, I'm screwed.

 

[Michael9865]

I've seen a good amount of Eaglets built this way in the WN facebook group. I didn't think building it this way would be so popular.

A couple things I can remember being problems when I built mine is the tailwheel causing all sorts of CG problems and the battery tray size. I should have gone a lot smaller with the tailwheel - I think the wheel on it is a little over 1/2 inch diameter, when I probably could have gotten away with half that. It needed nose weight. Don't know exactly how much, I just put weight in till it balanced out right. I would suggest using a skid - when I built my Q-tee I was initially worried about it causing all sorts of problems but eventually I got the hang of it and now I never ground loop it. Just be sure to add about 1-2 degrees of toe-in on either wheel which will really help make it a lot less squirrelly on the ground.

I don't know if you'll have the battery tray problem like I did. Initially my idea was to put the ESC and receiver in the battery tray and put the battery on the top side, with a top hatch. It seemed like it would be easier to get to the battery that way, and it was until I discovered that 2s wasn't enough power and my 3s batteries didn't fit in the tray! So I had to move the ESC and receiver to the top (which is technically where they're supposed to go in the first place) Unfortunately when I added the slot for the gear it shortened the tray by about 7 mm so most of my batteries would then not fit in the actual battery tray. I have a few that that do fit, however they're no longer manufactured so once the ones I have are too worn out to be used, I'm screwed.

Thank you for the great feedback. I will keep that all in mind. I have been thinking of using the plywood circles to push the 3D printed motor mount further forward before adding any ballast weight.

 

[TooJung2Die]

Going tail dragger will throw off the balance and require ballast to offset the missing nose wheel and added tail wheel. I find a 500mAh 2s battery to be more than enough power. It'll pull multiple loops at half throttle. I have the receiver in the nose on top, the battery bay below behind the firewall and the ESC is under the servos. All nice'n tidy. No ballast at exactly 7.0 ounces. Moving around grams of weight matters on airplanes this small and light.
Now that I have the tiny FS2A receivers I like the electronics layout I used on the Jr. Skylark 250 better.

 

[Michael9865]

Thank you for your great feedback. I will keep that all this in mind. the Jr. Skylark has a nice clean layout.

 

[Michael9865]

Updated the second post for your viewing pleasure. I have considered a few different main gear options. I finally landed with the wire main gear like the original design. I sandwiched the wire in between two plywood pieces. I considered sewing and epoxying the wire gear to a single bulkhead, an externally attach wire gear like the Roaring 20 had, and I also revisited using a flat stock aluminum gear.

 

[Michael9865]

Updated the second and third post for your viewing pleasure. Getting closer to a completed fuselage.

 

[Michael9865]

Updated the third post with what I will call step 6 of the fuselage for your viewing pleasure. Next step will be to build the tail feathers.

 

[speedbirdted]

About the tail feathers, if you want to steer the tailwheel off the rudder (if you are adding a wheel) you have to either move the rudder back or not have the tailwheel all the way back.

 

[Willy Nillies]

Unless you are flying off pavement all the time, don't add a tailwheel or any mechanism to have one. It adds a significant amount of weight to the aft end and you will have to add 4 to 5x that weight to the nose to offset it.... your all up weight goes up and flight performance suffers. A simple lite ply skid would be your best choice.

Sincerely,
Doug and Becky
WillyNillies.com

 

[TooJung2Die]

your all up weight goes up and flight performance suffers.

I'll second Doug's comment. After building two Willy Nillies kits I'll be looking for ways to lighten the airframe, not add to it. The Eaglet weighs 7 oz, the Skylark 6.9 oz. Neither needed ballast. The goal for the next one is 6 oz. Light is might and every gram you can eliminate on airplanes this small will make it fly better.

 

[Michael9865]

Updated the third post with what I will call step 7 which was cutting out the tail feathers From the laser cut sheet. If all goes well I might get to the wing construction tomorrow. 😏