One Sheet Warbird

[rcspaceflight]

I don't know about you, but I'm broke. I really want to buy an EPP Bf-109 from Hobby King, but I don't have the $40 for it. :black_eyed:

I've just always wanted a profile warbird. I dunno why. They just look like fun. Simple, yet fun. As much as I like the Bf-109, the P-40 just seems more right in profile form. Again, I dunno why.

So I designed one. (Profile P-40)


As much as I plan on building and testing it, I don't know when I'll get to testing it but building should be tonight or this weekend. (Not sure if I have DTFB here.)

Again, I don't know about you, but I hate taping tiled plans together. So I purposely make it measure and cut. Some of the corners are too square, but it's up to the builder to round them off before cutting.

Foam board layout:


Fuselage plans (make 3):


Rudder plans (feel free to make one fuselage with the rudder already on it):


Elevator plans (really needs to be rounded off):


Wing plans (wing tips need to be rounded):


Kf Step is a 2" by 30" piece cut of the one sheet. Use wing plans to make flush with the leading edge.

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By my wing cube loading calculations, the plane needs to stay under 10 ounces or 280 grams. Which should be easy enough to do with a light (mini swappable) set up.

I'm still debating if I want to peel off the paper and use packing tape or keep the paper on the foam. I will probably beef up the plane with bamboo skewers either way.

I thought I would share the plans now incase anyone else thinks it's a good idea/design. I'm not sure on the control surfaces either, but it will definitely me bank and yank.

The wings should be mounted with the tail edge on the end of the flat bottom of the fuselage. There should be a relief cut into the fuselage for the Kf step. I'm not sure on the elevator placement, but will probably be best on top of the fuselage similar to this photo.


I know it's pre-mature but I thought I would share anyway.

 

[johnmw]

coming up pretty good,
looking forward to its finishing.

 

[Christopher14]

Now I have to build one. 56 projects and counting.

 

[rcspaceflight]

I started cutting it out and made a mistake already. Yee Haw!

I caught the mistake before I actually cut it out, but didn't care enough to fix it.

Pictures so far:

Poorly hand drawn rounded wing tips.



Rudder drawn onto the first fuselage piece. Note the straight line under angled fuse line per plans.


Wings on bottom, then KF step (don't forget those 2 inches!), then first fuselage piece.


Elevator that I didn't bother trying to round off.


Blurry picture of foam usage.


Notice the mistake? I should have pushed the piece with the rudder on it over an inch or so. (I used the first fuselage piece to trace out the other two.)


I used the cut out wings to trace over the 2" KF step so the front is flush.


Notes: I certainly did not do a very good job measuring it out. I guessed with the 90 degree angles for the measuring points instead of making sure they are 90 degrees. I don't think it's big enough of a plane for it to need to be perfect. Plus there are no A or B folds. It doesn't have to line up perfectly.

I also gotta say, as much as it's time consuming to measure everything out, it's still a lot faster than cutting out plans and taping them together.

 

[ViperTech]

I really like the BF-109 I flew it on my sim quite a bit. The sim version is really easy to fly. Will be watching to see how this comes out!
Looks good so far!

 

[rcspaceflight]

I have the airframe done. Well, I have to cut out the ailerons, but far enough for now.

After hot gluing the three fuselage pieces together, paper left on, I inserted a couple of bamboo skewers for even more strength. Yes, the entire thing. But I didn't glue the skewers in. Just friction fit.



Jumbo Craft Stick firewall. I plan on just using two screws to hold the motor on. Which should be fine.




I removed part of the KF step instead of cutting into the fuselage to make the wing/fuselage joint flush.


Bamboo skewers added to wings for strength.


I sloppily cut out a notch into the rudder for the elevator.


And it looks terrible.



Current weight is 105 grams. Shouldn't be hard to stay under 280 grams.

 

[johnmw]

did the elevator went in as it supposed to?

 

[jh1985]

looks cool cant wait to see how it works. If it does ill build one too.

 

[rcspaceflight]

did the elevator went in as it supposed to?

Well..., yes. I made the slot so long, then I actually cut the elevator into the stab and ended up just making it bigger than I was thinking.

It's what happens when you free hand something without any planning or thinking.

 

[ghost civic]

I should like to see how your final plane flies.
I bought a plane that is basically the same as what you looked at on hobbyking...I got mine from nitroplanes as a kit/most electronics. the kit had really poor instructions...fortunately I had built enough DTFB planes to figure it out. (ithink the ARF kit was on sale for $60?)

I have to say, it is a DREAM to fly. Unlimited vertical flight, a decent roll rate....but not so fast that it would get you in trouble. it has some dihedral as well. It flies well at high speeds and low speeds (has nice low stall speed) The profile part of the plane gives it great power/weight even with a tiny motor. and a 1000mah 3s gives decent runtimes. It is my fastest plane for sure.

I only wish they came with landing gear. And that type of foam doesn't like packing tape. hot glue works ok tho.

If your DTFB version works well, I might want to build one. The only things I wish me nitroplanes version had was landing gear and slightly larger ailerons.

 

[rcspaceflight]

Hopefully I'll finish it tonight (like, right now, after I eat). I'm going with a 1300kv motor with a 8x4 prop and a 3S battery. I know if I go with my 500mah 3S it will be light and grossly over powered. But I may go with my 2200mah 3S battery. It will be "too heavy" but will still have about a 2:1 power to weight ratio. I'm leaning towards the 2200mah battery. It won't fly slow, but it should fly fine, especially in the wind.

 

[rcspaceflight]

I have the electronics added and it's current weight is 215 grams. (If I remember right, that's about the weight of a 2200mah 3S battery too.)

Hopefully I'll finish it off tomorrow and maiden it. Soldering is involved to finish it off, so we'll see.

Center of Gravity is no concern with this design. Yes I have the elevator (9gram) servo at the tail, but it's still nose heavy with the 2824 Hobby King motor.






Ailerons are 2" which may be too small with how much they taper off.

 

[rcspaceflight]

I maidened it today. Hand tossing it at full throttle probably wasn't a good idea. It rolled left and then biffed it. I think it's fixable, but the wings are a bit loose now.

It definitely feels like and looks like it will fly. But not fly great. It will torque roll, it will tip stall, it will stall bad. But it still should be a fun plane.

Honestly I'm not very interested in flying right now. I hope to fly a few of these this Spring/Summer and then write it all out into an article. If it actually flies well enough. But I don't see why it wouldn't.

I probably won't really test the design until the Spring. (Or even build a new one until then.)

 

[jamboree1]

When i see a profile design i think 3D and huge control surfaces. This might be why youre's doesn't fly like expected

 

[jamboree1]

I see a few more design errors, i can comment if you want

 

[ghost civic]

it would be a bit tricky to re-create my Tech One p-51's design in foam. While it is a warbird, it flies more like a trainer. It has more power and speed than a trainer, but it is easier to control than a 3d profile.

The EPP wing has a shape to it that promotes great glide and low stall speeds. The wings also have dihedral....that makes a big difference in stability.

The front of the wing tapers forward toward the fuse, and the CG is far forward on the wing. I believe the motor mount also has some thrust angle to it.

if you were to remake the wing, I would suggest not tapering the aileron in order to make it larger. And you may need to add some thrust angle to the motor. Also, mine flies amazing with a 1000mah 3s. any more weight, and it would be very nose heavy. And having it be overpowered is part of what makes my p51 fun...it is the only plane I have flown that has unlimited vertical ability.

 

[rcspaceflight]

I think thrust angle was the issue. I did have too much throw and plenty of control surface. I just didn't have time to react.

 

[ghost civic]

I think thrust angle was the issue. I did have too much throw and plenty of control surface. I just didn't have time to react.

sometimes being able to hand launch off of a hill gives you extra time to react...but I totally understand what you mean. If you are hand launching a maiden flight yourself, sometimes you only have 2 seconds to get your hand back on the stick and make the right correction.
Wish sometimes I had friends that were into scratch building....that way we could fly together and I would have someone else to hand launch a new plane, so my hands could stay on the controls.