Modified Light weight Olf Fogey / The Fish mashup

[Coersum]

I wanted to try to make a slow light plane so I took inspiration from The Fish and FT Old Fogey. It's not a strong plane but so far am happy.

Wing:
Mostly The Fish wing, except 30" (lighter wing load) center piece + 2 x 10" pieces for polyhedral tips. Modified the profile just a bit and just figured measurements as I was cutting foam, not sure on angle, I just used a coffee cup for an angle I liked. Might need a spar, will see once power tested. Not very strong.

Fuselage:
Skinny version of both planes with raised elevator to get a thinner fuselage. For the 50" wing span, I read it should be around 35-36" fuselage but wanted it to fit in 30" piece so shortened it. I only cut both sides, then added pieces here and there top/bottom for strength where needed to save on weight.

Stabilizers:
From what I remember reading, making the horizontal stabilizer a bit bigger might help prevent too twitchy reaction on short fuselage but I may have made my elevator a tad small (was just figuring things as I went) but adding throw should help.

I wanted everything to be a bit modular since I would most likely have to move things, so servo box, motor mount and stabilizers are mounted with barbecue sticks (see pics).

What I ended up with: 50" x 10" under cambered wing, short thin (compared to the The Fish and Old Fogey) body.
Total AUW with 1000Mah 2S = 330grams / 11.6 oz which will be powered by a 2205 1300kv with 9x4.7SF prop (that's what I have)

Sadly my esc isn't working so waiting on replacement to test. I did some glide test with some clay on motor to simulate prop weight and surprisingly it does well. We will see when I get the new parts for maiden flight. It's not the prettiest plane but so far it glides well and hopefully will do good in powered flights.

Pretty happy with the glide test, I gave it a bit of down elevator at the end and shouldn't have, it would have went much further. The wing might need a spar, you can see it flap a bit on my throw. Everything was in it, including some clay to simulate prop + prop saver weight.

 

[Gazoo]

Right on man! Looks like it will be a nice flyer. I'm waiting for that maiden vid...

 

[TEAJR66]

That is looking great. Please keep us posted.

I have a couple of those fully under cambered wing designs at a 30" span. They will float around for about 9-11minutes on a 2S 500mah when I use an 1806 motor and 5x3 prop. Nice and slow, but they are handful if there is any wind.

This one was an early version and was way over powered and weight.

 

[Coersum]

Thanks, I made it bigger than I'd like but it was needed for a low enough wing load with the parts I already had. Later on I might try a smaller one with smaller parts and yeah I'm sure those things won't handle much wind. I have an esc coming in the mail so hopefully we'll soon know how it flies

 

[Pigfarm1403]

I think somebody should make a seaplane version of the old fogey

 

[Coersum]

Finally the day has arrived and it's ready to take its maiden flight..step outside.. WINDY... oh well, let's try in the small test strip I have next to the house lol

Maiden was very short, it had almost NO rudder authority (the wind didn't help but couldn't turn either side). Changed throw to 100% from 60% and still almost nothing. Also the elevator had too much so lowered that too. Test again and still almost no rudder.
*dinner time*
Took it inside and taped a piece of foam to the rudder (doubling it), I will replace it later and lower the servo horn hole too.

The plane still has a bit too much elevator which I will reduce when I go to the actual flying field but rudder feels much better and can fly pretty slow, just hard to do in my very small test strip with a plane that size. I will be bringing it to Flite Fest Ohio (unless it breaks before that, in which case I'll build a new better one).

 

[Gazoo]

I'd say you have a very nice start. Looks like a solid slow flier. That rudder is about the size of Texas...give er take.

 

[Coersum]

yeah I'm liking it so far. Looking at the video again, I noticed I had to push some up elevator here and there, I haven't had time or space to trim it yet, could also just need to adjust CG.

Yes that rudder is pretty impressive lol. I'll try reducing it and linking the pushrod on the hole closer to the rudder on the servo horn for more throw.

If that's not enough, should I decrease the vert stabilizer length or raise vert Stabilizer height to make the rudder bigger ?

 

[Gazoo]

Maybe someone else can comment (or correct me) but I think that the drawback to having a large rudder/vert stab is a lot of Dutch Roll. Kind of a tail waggle when you try to turn. That and polyhedral wings cause dutch roll.

I love the way it floats. Bet it's going to be a sweet flyer at sunset when the wind is nil.