"Sonic" .46 nitro build

[tudordewolf]

For my second nitro build, I put together a Phoenix Models Sonic, low-wing version. It's described as a .25-.32 sized plane, but after much deliberation I went with an OS .46 LA. I wanted to run a semi-vintage engine, and considering the 25la weighs ~270g w/muffler, and the 46la weighs 350g, it seemed like an obvious choice for only 80g more on a ~1800g plane.

The ARF was a steal at $99, but it was definitely a bit more rough around the edges than the Avistar I built before it. Little things needed to be reworked, the servo mounts in the body were a single layer of ply. I glued in an extra layer behind them so the screws would actually have something to grab onto. The mounts are a weird size, 16x32mm while most mini servos are 15x35, so I had to rework them a bit. The only servos that fit the default mounts appear to be some hitecs in an odd size.

The screw included with the fuel tank wouldn't fit between the fuel pipes, I had to sand it down in a drill until it fit.

A lot of reviews mention that the included controls rods for the tail were too short. I found included controls rods were usable without being cut, just bent at the very ends, but I also had to turn the servos around in their mounts and there wasn't even 5mm of extra left.

Break in went smoothly, engine tunes to 10,400 RPM and holds 250°F with an APC 10x7, I'm hoping to take it on its maiden flight this weekend.

 

[Greywolf74]

Thats great stuff right there! I love seeing nitro planes and helis! Seems like so few people do that anymore! <3

 

[Tunedfrog]

Great looking plane and she sounds sweet.

 

[CertifiedMike]

Agree! That's music! Sounds like an angry Stihl saw!

 

[gandalfnz]

Very good!

Look at that beautiful oil coverage on the right wing.
LA46 is singing.
Apply silicone where exhaust needs the engine block? Usually oil from there.

Have you ever done any research on what we can spray on the covering, like a protection film? I read about this a while ago on other forums.

I have been side tracked by multiple project/restorations I am doing amongst which are with SIG 4 Star 120 and 40. Pitts, warbirds....etc.

I will post a few pics in the usual thread.

 

[Chubaka]

Very good!

Look at that beautiful oil coverage on the right wing.
LA46 is singing.
Apply silicone where exhaust needs the engine block? Usually oil from there.

Have you ever done any research on what we can spray on the covering, like a protection film? I read about this a while ago on other forums.

I have been side tracked by multiple project/restorations I am doing amongst which are with SIG 4 Star 120 and 40. Pitts, warbirds....etc.

I will post a few pics in the usual thread.

Helps it glide through the air better. That wing is now a butter knife cutting right through the butter.

 

[tudordewolf]

Very good!

Look at that beautiful oil coverage on the right wing.
LA46 is singing.
Apply silicone where exhaust needs the engine block? Usually oil from there.

Have you ever done any research on what we can spray on the covering, like a protection film? I read about this a while ago on other forums.

I have been side tracked by multiple project/restorations I am doing amongst which are with SIG 4 Star 120 and 40. Pitts, warbirds....etc.

I will post a few pics in the usual thread.

The video doesn't even show how oily it got by the end of the break-in, the entire top of the wing had a layer of oil so thick it was forming "runs" like when you use too much spray paint and it drips down.

The brodak air filter worked nicely, no complaints.

I did the backplate and exhaust with silicone, no leaks there. A fair amount of oil seems to be coming from the front of the engine, enough that the bottom is greasy by the end of the flight. It also seems to tune a bit richer than the AX, just "wetter" in general.

The upward-facing deflector is definitely not as effective as having it point downwards. I was hoping it would "throw" the exhaust over the wing in flight, which it does, but when it's idling the thrust isn't enough to push the exhaust away, it just swirls it around the whole plane. I'm thinking of pointing it downwards, but I'm not sure it would clear the wing, and then I'd have to wipe off both sides. I took for granted that the Avistar with its AX only leaves a little oil on the tail and none on the engine itself.

I haven't given much thought to sealing the skin beyond the usual methods- Overlapping seams, epoxying hard-to-reach areas, & raised edges. I suppose during a build one could even pre-seal certain pieces of wood, like the entire front firewall, rather than after assembly.

I use a couple "multi-surface" wet wipes to degrease the planes when I'm done flying and it keeps them pretty dry.

Excited to see those other builds! My next one will be a 4-stroke and a warbird too, that P-51 I've been planning

 

[CertifiedMike]

Do you have a lot of oil in the fuel? Maybe change %? Just a thought because by sound and that vid, maybe a bit smokey but she sounds great!
On the nitro cars we can get away with silicone tubing on the exhaust to help direct oil away from the bodies.
I don't fly so I don't know if this works on a nitro plane. It seems reasonable though.
Great build!!!

 

[tudordewolf]

Do you have a lot of oil in the fuel? Maybe change %? Just a thought because by sound and that vid, maybe a bit smokey but she sounds great!
On the nitro cars we can get away with silicone tubing on the exhaust to help direct oil away from the bodies.
I don't fly so I don't know if this works on a nitro plane. It seems reasonable though.
Great build!!!

I'm using torco's 15% nitro, 18% oil blend. That is a good bit higher than the car/truck engines get, but it's on purpose, since these engines run at WOT for longer and need more lubrication and cooling. Like I mentioned, the engine in the video has no ball bearings, just a plain brass sleeve that the crankshaft spins in, constantly oiled by the fuel-air mixture flowing in. In my cars I run Torco's 30% nitro, 10% oil fuel, and they absolutely rip.

The smoke trail from a nitro plane becomes a nice "feature", it actually leaves a crisp line in the sky for a few seconds. If I don't see a puff of smoke when I throttle up, I have to wonder if I'm not running too lean.

I do have the same kind of silicone extender on my exhaust, it's just that I'd have to pipe it all the way to the back of the plane to keep it from getting all over everything. Even my nitro onroads will have one side of their shell covered in oil after a day's driving.

 

[CertifiedMike]

I imagine the smoke trail looks very cool up in the sky!
I have been to a few r/c plane meets. I don't fly but boy some of those planes and the folks who were flying them... WOW!!!
The time to build them and then learn how to make a 1/4 scale plane doing stunts that I wasn't aware a winged aircraft could EVER attempt!!! lol!
Yes, the "exhaust tube" to keep your plane clean is what I was thinking could be helpful.
Nitro cars are the same way. If there's no smoke, you're doing it wrong!

 

[tudordewolf]

And, smashed it. Got disoriented flying it directly overhead, tried to roll out of a dive and rolled into it. Plane neatly separated into wings, fuselage, and engine compartment. Engine feels fine, will see if it still runs.

The wreckage is saveable but not for less time or money than a fresh ARF, the wings would be worth it but not the fuselage. The tail is undamaged which offers some potential.

 

[CertifiedMike]

That looks pretty bad. I hope you can salvage enough to fly again!

 

[tudordewolf]

Did catch a video of its second-to-last flight:

 

[WickedFog]

Hearing it run, and the look of the plane brings back memories of my dad's first RC plane build. I used to love going out to the field where he flew and checking out all the other airplanes. And the smell in the air... it was like crack lol. I was hooked.

Did catch a video of its second-to-last flight:

Very cool!

 

[tudordewolf]

Reincarnated and flying again, the engine doesn't even look like it's been through a crash:

 

[Greywolf74]

Love the OS engine <3

 

[CertifiedMike]

She's looking great! Nice job on the clean up!!!

 

[tudordewolf]

She's looking great! Nice job on the clean up!!!

Thanks! ...it's really a fresh build of the ARF kit since it's currently $99. The engine & receiver were saved, servos replaced just in case.

 

[gandalfnz]

I only just saw this one.
You must like the bird a lot, since you purchased another one of the same after you crashed the first?

Eventually they all go down, at least thats what I think. We can do all the checks in the world prior to take off, but one servo failure and poof!

Its all a great learning experience, like not to fly over the pilots box area

I also instinctively always pull up on the elevator when something is wrong, which can save the day, or ruin if you are flying inverted.

 

[tudordewolf]

I think it was sort of like "undoing" the crash, I still wanted to have that plane in my collection, and the engine had survived, so it begat a rebuild.. It's an easy kit, goes together in a weekend, and I had the chance to do a crisper job putting it together, having already made one just a few weeks ago...

I had it on its side and it only loses altitude faster like that when pulling "up," and it stalls quickly. I intend it as a practice plane for more aggressive flying, and silly experiments like the following exhaust setup, since it collects a substantial amount even with a deflector:

I removed the muffler baffle to lessen the overall resistance. Considering I'm not pushing this engine past ~11k rpm, I don't think the tube will have too much of a detrimental effect. I was tempted to run it all the way to the back but that would involve a lot more work mounting the support clips. I'll try to trial it next weekend if the weather permits.

Edit: I see it doesn't clear the aileron, I'm reworking it a tiny bit higher