Cessna 337 Skymaster Inline Twin. Full Fuselage

[Cobra1365]

Getting a little closer. Wrestling with best way to wire together the two ESCs given the space I have to work with and where the battery sits. I may modify the battery location to just forward of the wing saddle thru Former 5.

Wheels are off the Hobbyzone Cirrus. Had to build a wood structure for the nose gear plate to mount to. Then used a couple of pieces of hobby ply to build a saddle for the mains.

 

[Cobra1365]

95% complete. Poster board did not lay down as nicely as I wanted. I think I’ll trim out window frames in red.

still need to adjust all the servo throws.

Steerable nose gear is just about at my wits end! I may just have to put a fixed nose gear in it.

 

[Cobra1365]

My wife suggested I spruce it up a bit more and make it match the Texaco collection I have...

 

[Aireal Anarchist]

tell her.... good call, it looks great, Im going to build one too at some point

 

[quorneng]

Mine is an O-2 Vietnam Special Ops decoration.

No undercarriage it is a hand launch/belly land.
All 3 mm Depron apart from a small amount of balsa in the wing spar.
Masses pf power from the Emax 2812s driving 9x6s. In fact the plane's scale was selected so these props were true scale diameter.
The front motor can be switched off in flight which allows the 2200 mAh 3s to give a cruising duration of up to 40 minutes.

 

[Aireal Anarchist]

Mine is an O-2 Vietnam Special Ops decoration.
View attachment 173038
No undercarriage it is a hand launch/belly land.
All 3 mm Depron apart from a small amount of balsa in the wing spar.
Masses pf power from the Emax 2812s driving 9x6s. In fact the plane's scale was selected so these props were true scale diameter.
The front motor can be switched off in flight which allows the 2200 mAh 3s to give a cruising duration of up to 40 minutes.

nice build.....first time I saw an Oscar Deuce was in Vietnam, I think the national guard had some too, cool plane

 

[Cobra1365]

Added the finishing touches today...windows etc. Had to adjust the power pod some.

Test run up and down the driveway. Seemed to do OK. Slight veer to the left. But, I think that was from the power pod being out of alignment (motor was canted some). Adjustments should have fixed that.

if weather cooperates, maiden tomorrow afternoon!

 

[Cobra1365]

Maiden flight today. Semi-successful. As you can see from the video, it really wanted to pitch nose dow, even with almost full up trim. I had to hold approx 1/2 deflection in. No big change regardless of power setting.

CG was spot on according to plans.

I feel like the horizontal stab angle of incidence might be too great. Anyone else experience handling issues on their maiden?

 

[Cobra1365]

Second flite went a little better. But, this time she wanted to roll hard left. Landed to find the left aileron control horn had separated! Only got the one flight in before the winds went out of limits and Mr. Farmer Man showed up to tend his crops (I won’t fly over him when he’s in the field).

Today, I tried again. Takeoff was nice and smooth. She still want to roll left a bit...not as bad. Slight pitch down.
brought it by for a low approach to see if we could get a better look. As I was climbing back out, I dont think I got enough throttle in before, what my eyes thought, was going to be an issue with the trees. I pitched up, but got into a stall right where we have the worst wind shear at our field. The resultant loss of control and gust of gravity took her straight in. I found out the hard way that she drops a wing when she stalls!

Both tail booms sheared off just forward of horizontal stab. Power pod/firewall sheared off. Rear motor dislodged. Nose gear broke off. Ego severely bruised!

One thing I noticed...the way she flies, she has a nose (fuselage) down attitude even though the wing is level. So, I’m thinking the incidence is incorrect.

Back to Dollar Tree!

 

[Cobra1365]

One thing I noticed...the way she flies, she has a nose (fuselage) down attitude even though the wing is level. So, I’m thinking the incidence is incorrect.

!

I plan on building another of these. Just too cool an airplane not to.

But, as I was reviewing my build, there are a few things I need to pay a lot more attention to. As noted, the airplane looked like the nose was sagging. If you look at the attached photo, you’ll see the wing was sitting in the saddle with a pronounced positive angle of incidence. After looking at other‘s builds, the angle appears to it should be near zero.

I also found (after the mishap) that I had a slight twist in the wing, causing the roll.

 

[quorneng]

If you can keep it light enough the Cessna 337 has a fantastic performance.
My Depron O-2 doing its stuff.
Not so many scale planes would I loop that low as in the first one.

 

[tnkgnr]

I plan on building another of these. Just too cool an airplane not to.

But, as I was reviewing my build, there are a few things I need to pay a lot more attention to. As noted, the airplane looked like the nose was sagging. If you look at the attached photo, you’ll see the wing was sitting in the saddle with a pronounced positive angle of incidence. After looking at other‘s builds, the angle appears to it should be near zero.

I also found (after the mishap) that I had a slight twist in the wing, causing the roll.

I've built four of these now and none tipped to the side when stalling. I'll routinely get up to altitude and cut the throttle and just hang with full up elevator and it just slowly comes down in a straight line. I built one with retracts and while still fun to fly, I didn't like the performance hit from that extra weight. I think once you get the build right, you're going to love this thing even more!

 

[Cobra1365]

As I am preparing to build my second, I came across this thread on RC Groups...Too Long Battery Wires

On my first airplane, I followed the instructions and then used a single 3s 2800 battery. It was pretty warm after the first Flite. I’m wondering, given the info in that thread, would it be more feasible to use two smaller 3s batts to prevent possible damage to the ESC? Seems 1300’s would fit with minimal impact to adjusting CG.

thoughts?