The test stand.
|Specifications for the JBA .56 ABC:|
|Output:||1.65hp @ 17,500rpm|
|RPM Range:||2,500 - 12,500|
|Jiangnan Blue Arrow:||JBA|
|Kangke USA:||Kangke USA|
There is just something about nitro fueled models. There’s an excitement about them that electrics just don’t have. Don't get me wrong, I love electrics: They are clean, quiet and can make a plane do just about anything. But folks, sometimes size does matter and there have been times when I couldn’t get into the expense and complexity of really large electric models. Not to mention that as I get older, that 35 inch wing span gets harder and harder to see, and many of the outrunners are so quiet that I can't hear them at all. This review is my first step in a series moving me toward the nitro sport again.
Several months ago I noticed an advertisement in Model Airplane News for a nitro engine that I had never heard of before. I have always been one to try new products and I believe companies need a chance to prove their products, so I did a little research.
Jiangnan Blue Arrow, known as JBA, is a Chinese company that produces a variety of engines for the modeling industry. While they are relatively new in the US, they have been producing airplane, car and helicopter engines for the European and Asian market for several years. I was impressed with several areas of their production. First, they are an ISO9001 so I was not going to be faced with non-conforming parameters (in other words, I could purchase glow plugs, and props that fit). Second, they use CNC machining extensively. I could tell very quickly by looking at their website that attention to quality was important, so I took the leap and purchased a .56A ABC engine.
I was also very interested in this engine because it was affordable. For many years I was building and flying nitro models all the way up and through Byron Originals giant scale planes. I sold everything once, and then many years later got back into the sport with electrics. At some point I just had to crossover, or back over I guess, to glow. This engine presented an opportunity to do just that without completely emptying my wallet.
Kangke USA distributes JBA, and shipped the engine to me promptly.
Included in the box were the engine, carburetor and muffler. None of the parts were packaged in foam, but the engine was well-wrapped and there was no damage.
All the parts were nicely oiled to keep them from absorbing any moisture. The engine is painted with a machine finished head and I was impressed with the quality of the paint. It was very glossy, and seemed thick enough to last and to resist heat.
The first thing I did was read through the instructions, which consisted of about one page of precautions and one page of setup. They recommended a break-in run, so I built a test bench.
This engine is typical of two-stroke nitros. It has a high-speed needle adjustment, a low-speed adjustment and a throttle stop adjustment. The low speed adjustment is factory set and there was no need to make any changes. The high-speed needle was initially adjusted to 1.5 turns.
I used a 15% fuel since JBA recommends at least a 10% mix. I used a medium range glow plug.
Just as the instructions said, a few counterclockwise flips and it was running. I varied the speed through the first tank of fuel and was immediately impressed with both the high end and low idle. I kept the fuel rich for the break-in period. The idle “cackles” and sounds like a motorcycle. The muffler did its job.
I ran another tank of fuel through the engine to make sure I was satisfied with the running. Initially I opened the high-speed needle to about 1.75 turns, but I was not comfortable with that setting and rather than guess, I tested it in two ways; with an infrared sensor to measure the overall head temperatures, and the recommended pinch test.
I could tell I was running hot. Initial measurements at the 1.75 setting were showing temps over 400 degrees Fahrenheit. At the 1.75 setting, it was not showing any signs of increased RPM’s. I increased the setting and saw lower head temperatures (at about 350 degrees) and achieved a slight increase in RPM as I pinched the fuel line shut. Ultimately, I was comfortable at about three turns open. The idle was reliable and the transition for idle to full throttle was smooth.
I installed the JBA .61 into a Fun-50, and ran it several more times with three different props. Using the suggested 11x6 prop, I got a smooth idle at around 2,700 RPM and a wide open throttle of 12,500 RPM. An 11x7 prop didn’t show much change, and had a slightly higher idle of about 3,300 RPM and a WOT of about 11,900 RPM. The last prop was a 12x6 prop and idled just under 2,800 and a WOT of about 11,700. Overall I was pleased that there was little difference in the three props’ performances. I did not make any adjustments to the needle settings and I was always in the 300 degree or less range with all three props.
The JBA .56 was installed in a Kangke USA Fun-50 (review coming soon on RCGroups) and I continue to fly this combination with great performance and power. This engine is slightly more power than required for the Fun-50, but the vertical performance, speed and handling are worth the boost in engine size. There is a strong resonance from the muffler that provides the feel of power and when coupled with the right maneuvers, the realism is fantastic.
See the soon-to-be published review for flight video of the JBA flying the Kangke beautifully!
I was quite proud of myself for making the leap from electrics and for getting any glow engine to run again. I realize I had little to do with JBA’s engine working properly, but I enjoyed the process. I found the install in a Kangke USA Fun-50 to be simple and enjoyable as well.
JBA has done a great job of producing a quality engine that is manufactured to exacting specifications and that made me comfortable in my transition back into nitro. I will never abandon all my electric flyers, but there is something exciting about the nitro models. So, whether you are returning to nitro, entering for the first time, or just looking for a great performing, reasonably priced engine, the JBA line may be just what you're looking for.
Is it a plain bearing or ball bearing engine?
BTW, our engines a "glow", not "nitro". Nitromethane is not a must in order to run them but a glow plug is.
Joined Dec 2007
regarding glow plugs
I think you wrote a really good review. I recently read it and it prompted me to get one of the JBA engines! One thing the included sheet doesn't state is whether the glow plug is "long" or "short". I know, usually, rule of thumb dictates a long plug for larger engines. Before I go pulling off the head I thought I'd ask here, first.
Also, on installing a prop, the instruction sheet states "so that it is coming onto compression at the 2 o'clock position"
Does this refer to when the piston starts coming up, begining the compression stroke or when it's at TDC?
Thanks so much for your assist!
What's the mid-range and transition like?
I had a TigerShark 56 (same factory, earlier design) and that was *awful*.
Since i fly mainly 3D, I like my engines to be ubeer-crisp in the mid-range with absolutely no hesitation in transition.
So, if you go to 1/3 throttle -- do the RPMs instantly stabilize or does the engine speed-up/load-up during the seconds that follow?
After holding a throttle setting just above idle for 30 seconds, does the engine instantly transition to full throttle when commanded -- without coughing, spluttering or hesitating?
So far I've yet to find a Chinese-made overbored engine that passes those tests.
I've had a few folks tell me "yep, it's perfect" but when they demonstrate that "perfection" to me it's *far* from adequate for 3D. I guess that unless someone flies 3D the often don't understand what a good mid-range and transition really is.
A circle-flier's *great* mid-range can be a 3D flier's nightmare
XJet,I m not into 3D at all but Im using 4 JBA 56 F engines and manufacturer says engine and carb designed for 3 D (for F types).I have some tests on air to pull model into nose up and trying to hold by engine and it seems engine (and carb sure) responds well.
Be careful Blueline series JBA s have classic ,old style carbs and some design differences from F types.
If you intend to have one,try to buy F type.Also F types have 2 type carbs.Either similiar to OS 55 AX ,LSN just near the HSN or LSN is in the center of throttle arm .
The first one was the only carb once but now it seems latter (classic style LSN) one is coming with engine but it is possible to come with either.
If the carb is OS type,so be careful.The LSN is very,very,very sensitive.It has a total 35-40 deg. travel and sweet spot can be missed only by touching the screwdriver to the needle without move.I dismantle one and found a complex design inside the carb.
So some rich midranges(but not fat) you can feel according to your adjustments(I mean level flight) but I think this helps for 3D flying but transition is great.Not for 3D but I always make sure my engines to pass that at over idle rpm to full transition.Also F type 56 is some kind screamer than SK style torquer.
thanks turk1 for these great informations.
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