JBA 56
#1
Thread Starter
My Feedback: (51)
JBA 56
I just bought 2 new JBA 56 2 stroke engines from Kangke. One I bought a couple weeks ago and the other is on the fed ex truck to be delivered tommorow. The first one I mounted on a scratch built NJ One Profile I built, but I won't be breaking that one in or flying that plane till spring. However..the other one that is scheduled to be here tommorow is going on a 40 size Kaos that I plan to fly January 1st at a Frozen Finger Chili Fly. My question is....is anybody been running these engines in the extreme cold and if so...how do they do? I will be using 15% Coolpower and probably drop in either a O.S #7 or a #6(A3) glow plug and run a couple 2 or 3 tanks thru it before putting it in the air on the 1st. I am going to find out soon enough how these act in the cold, but just thought maybe somebody might give me a heads up on what to expect.
#2
RE: JBA 56
JBA engines are robust engines.You can test all type plugs and no need to worry for damage.If you have problems check carb.Mostly o rings or dirt.If you can buy F type JBA 56 then you would be most happy.First class,powerful engines.In cold,you should prime it generously to start without starter.
11-6/12-5 props are best suitable.
11-6/12-5 props are best suitable.
#3
Thread Starter
My Feedback: (51)
RE: JBA 56
Thanks for the tips Turk1. I just installed the engine this morning. I stuck an 11x6 prop on it and installed an O.S #7 glow plug. I hauled everything outside eager to run a couple tanks thru it and wouldn't you know my glow driver battery is dead and needs charged. So I then resort to my glow driver that has a cord and plugs into my power panel and wouldn't you know my field box battery needs charged also!AHHGG! So now everything is on the charger...so I guess I will try again in the morning. It is about 18 degrees F out...so once I got everything hauled back inside...I decided to abandon my efforts today because I was cold.LOL It has been a couple months since I flew last and obviously my batteries havn't enjoyed sitting out in the cold garage for the last couple months!
#5
RE: JBA 56
ORIGINAL: martenson
Turk how is the 61, good or bad.
Thanks.
Turk how is the 61, good or bad.
Thanks.
FYI;I am using %16,5 full castor home mix no nitro fuel with market type methanol.With OS A3 ,Chinese 11-6 prop I have 13400+ RPM s on my JBA 56 F s
#6
Thread Starter
My Feedback: (51)
RE: JBA 56
ORIGINAL: Turk1
JBA engines are robust engines.
JBA engines are robust engines.
#7
RE: JBA 56
Thanks to castor oil,I have tortured many ways on my JBA 56F,mostly adjusting to max RPM(lean mixture) and full throttling vertical to clouds for minutes.Nothing negative at all,no harm at all etc.I removed baffle from muffler (no baffle in Blue Arrow JBA muffler though) and also removed all shims from head.
#8
Thread Starter
My Feedback: (51)
RE: JBA 56
Turk1
I also mix my own fuel and sometimes I use Cool Power 15% Nitro as well when I can get a deal by buying it by the case. I have not decided yet whether I want to use my own blend to break it in or use the Cool Power. When I make my own it is 77% Methanol..18% Klotz (20% castor/80% synthethic)...and normally just mix 5% Nitro and a couple drops of Armor All, but sometimes I will mix up some 10% nitro as well depending on the engine. I have quite a stock of Methanol...so I can mix up fuel pretty much how ever I want and when I want. Some engines like more nitro, some like less and some like none at all. I also have some straight AA grade castor, and I may decide to just use the cool power but ad a couple ounces of straight castor to a gallon. Them new JBA's would probably appreciate a little castor in the mix for break in.
I also mix my own fuel and sometimes I use Cool Power 15% Nitro as well when I can get a deal by buying it by the case. I have not decided yet whether I want to use my own blend to break it in or use the Cool Power. When I make my own it is 77% Methanol..18% Klotz (20% castor/80% synthethic)...and normally just mix 5% Nitro and a couple drops of Armor All, but sometimes I will mix up some 10% nitro as well depending on the engine. I have quite a stock of Methanol...so I can mix up fuel pretty much how ever I want and when I want. Some engines like more nitro, some like less and some like none at all. I also have some straight AA grade castor, and I may decide to just use the cool power but ad a couple ounces of straight castor to a gallon. Them new JBA's would probably appreciate a little castor in the mix for break in.
#9
My Feedback: (1)
RE: JBA 56
Turk has had the scoop on SK and JBA engines before anyone here in the US. I think they get them in Europe a long time before we do. I've not seen a .56F yet.
I have a JBA .56 and 2 OS .55AXs. With their stock mufflers the JBA and OS turn the same, withing a couple of hundred rom one way or the other depending on the prop. The OS does respond to a pipe or tuned muffler (Jett, in my case), while the JBA gets very little boost from one. I also tried 2 other mufflers on the JBA, the OS 55 and a Tower. Both showed 300-400 rpm lower than the stock JBA muffler. The JBA muffler is a little larger and, as I recall, the blue JBA actually has a .58 cu. in. displacement, which would need a slightly bigger volume muffler.
I also have an SK .50 and 2 of the .90s. They are easy starting and good running engines, just not high rpm engines. They are made for big props. 12-5 on the 50 and 15-6 on the 90 are the best ones I have found.
I am running 10% Omega, castor blend fuel. I forget the glow plug. 11-7, 12-5 & 12-6 props are good on the JBA.
I have a JBA .56 and 2 OS .55AXs. With their stock mufflers the JBA and OS turn the same, withing a couple of hundred rom one way or the other depending on the prop. The OS does respond to a pipe or tuned muffler (Jett, in my case), while the JBA gets very little boost from one. I also tried 2 other mufflers on the JBA, the OS 55 and a Tower. Both showed 300-400 rpm lower than the stock JBA muffler. The JBA muffler is a little larger and, as I recall, the blue JBA actually has a .58 cu. in. displacement, which would need a slightly bigger volume muffler.
I also have an SK .50 and 2 of the .90s. They are easy starting and good running engines, just not high rpm engines. They are made for big props. 12-5 on the 50 and 15-6 on the 90 are the best ones I have found.
I am running 10% Omega, castor blend fuel. I forget the glow plug. 11-7, 12-5 & 12-6 props are good on the JBA.
#10
Thread Starter
My Feedback: (51)
RE: JBA 56
I actually ran an SK 50 on a 40 size Bridi Vagabond I built a couple years ago....which is basicly just a Kaos with a turtle deck, but the problem I had with it was clearance. That SK 50 really liked a 12-5 prop but was really chopping grass running that prop. I had the same issue with one of my SK 90 as it was in a Super Sportster 90/120 I built off plans and it really did not have the clearance for a big 15x6 prop. I ran my other SK 90 on a Sig Hog Bipe for awhile and it had plenty of rooom to swing the large prop. They all ran great and were very reliable.....so I thought I would try the JBA's and hopefully not have the clearnace issues I had with the SK engines and turn up a few more rpm's since I am more of a pattern style flyer and not much for 3D which is what those big prop and big torque SK engines are best suited for..
#11
Thread Starter
My Feedback: (51)
RE: JBA 56
ORIGINAL: Ed_Moorman
I've not seen a .56F yet.
I've not seen a .56F yet.
#12
My Feedback: (32)
RE: JBA 56
I bought two JBA .56F engines from throttlestore.com in Norway.
The total with shipping came to $174.00US.
They seem well made. I have not run them yet.
The carb looks like a OS, however, the low end needle is still in the barrel on the throttle arm side.
The screw on the needle valve side appears to be used to locate the spraybar.
The case is quite a bit wider than typical .46 size cases.
Tony
The total with shipping came to $174.00US.
They seem well made. I have not run them yet.
The carb looks like a OS, however, the low end needle is still in the barrel on the throttle arm side.
The screw on the needle valve side appears to be used to locate the spraybar.
The case is quite a bit wider than typical .46 size cases.
Tony
#13
RE: JBA 56
JBA 56 F has some positive differences from OS 55.It has 6 headscrews.(OS has less then this).F type carb has 2 side clamp retainer on the block which prevents any carb loss risk totally and also one sided retainer's puncture risk too.I saw OS had lost carb screws.
OS 55 tends to loosen head screws but F type JBA not at all.(Though they seem same type head design).
JBA F type carbs have 2 options.First they were just like OS type LSN(which you can see still on second type carbs also but no function).I have many of them.But they have a negative side that the LSN was very,very,very sensitive(already between 30-35 ° total angle).Any newcomer cant handle on LSN adjustment.But inner design was very different and interesting.Also in time one had to fix LSN o ring because of leak.
Now they changed the LSN into old,classic style and still good, especially suitable for 3D type flying.Also JBA F carbs have bigger throat diameter than OS 55 carbs.
OS 55 tends to loosen head screws but F type JBA not at all.(Though they seem same type head design).
JBA F type carbs have 2 options.First they were just like OS type LSN(which you can see still on second type carbs also but no function).I have many of them.But they have a negative side that the LSN was very,very,very sensitive(already between 30-35 ° total angle).Any newcomer cant handle on LSN adjustment.But inner design was very different and interesting.Also in time one had to fix LSN o ring because of leak.
Now they changed the LSN into old,classic style and still good, especially suitable for 3D type flying.Also JBA F carbs have bigger throat diameter than OS 55 carbs.
#14
Thread Starter
My Feedback: (51)
RE: JBA 56
Well...I managed to get outside today and run a few tanks of fuel thru the JBA 56. It was around 20 degrees out so I installed a good hot A3 (#6) glow plug ...an apc 11X6 and filled it up with cool power 15% with no additional castor added. I figured the synthetic might perform just a bit better in the cold. That castor can get awful thick when cold. Anyhow....the engine started very easy and I had to leave the glow ignitor on for the first tank, but on the second tank I was able to remove the glow ignitor and she was idling good and screaming on top end even at a good rich setting. I didn't get my tac out ,but she really seems to have some real grunt, but next time I will check it with tac. The only thing I am going to have to fiddle with next time is the mid range is a little on the fat side. It may smooth out after a bit of running and it wasn't real bad, but I can tell it was loading up a bit in the middle and would hang for a split second in the middle when transitioning. However for an engine that only has had two tanks of fuel ran thru it.....things are looking pretty good thus far. I bought two of these JBA 56's....so I hope the other does just as well breaking it in.[8D]