Hi all,

i recently bought a used 40 size trainer with JBA engine from a friend of mine in chennai.
Attaching the pics,
Tested the engine with Rubbing alcohol and the engine runs fantastically with 2nd Flick,
Now needs some hardware to complete the plane, here goes my list.

Fuel tank,silicon tube for fuel line,
Landing gear,
glow clip
standard servos 4nos,
prop 10x7
spinner for prop
push rod for throttle.
fuel filter and hand pump.

Used/NIB stuffs are always welcome, please PM me your quotes.

my first preference should be the landing gear as i can buy the rest of the stuffs online, this is the one which i cant fine anywhere, it should be a nose wheel steering type.
Forgive me if i missed anything or misplaced any terminologies, i just graduated from my scratch-built Coro flying wing to this nitro.

Thanks All.

"tested the engine with rubbing alcohol"? Just this? the one found in medicine shops? no lube/castor oil? doesn't rubbing alcohol has some percentage of water in it? does it affect the engine? Lot of questions pop up from this statement of yours. Maybe someone can answer

Try lotus hobby (lotushobby.com) Mr. Probir Ganguly. He has the L/G you require, and lots of other stuff too

RCGroup http://www.rcgroups.com/forums/showpost.php?p=4184976&postcount=9

Quote from: beemer;4184976I have an old GP.07 that I've run 2 tanks of straight isopropyl alcohol that I got from the local drug store.

It would only start with an extremely rich mixture and using my electric starter. It needed to crank for about 2 seconds before it would fire up.  I was very impressed that it actually was able to run!  I was able to get it to run for about 10 seconds once the glow plug heater was removed.  It would slowly lose power and then sputter to a stop.  The engine never actually got "hot" to the touch.  The muffler got hot, but not overly hot. 

It actually sounded a bit quieter than with the glow fuel and the cleanup was a breeze! :cool:

Interesting experiment.

Pankaj, Actually i put 2 drops in the carb and flicked it and it ran for say 5 sec before it ran out of fuel, since i knew that the engine is not used for a long time and never knew whether it starts and having no fuel in hand, i gave this a try. the lable says it has around 40 percent castor oil. the other ingredients added in the spirit worries me more than water content. anyway, im not going to give it anymore try, this is just for testing purpose and im not going to try anything but methanol. and since i have no glow booster i connected a duracel 1.5v battery directly to the plug and started it. as quoted by sanjay sir, it doent smell or sounds. i  tried it in my hall where the pic was taken.

Just saw the site, stocks are awesome but nowhere a price is mentioned. will try to contact Ganguly sir by mail. thanks Sanjay. Mods please add this site to the Mega list of RC outlets.

You are welcome

http://soldcentralfl.com/flyingpenguin/murphysl.htm

Amazing Laws..

Enjoyed reading each one of them and could relate to each one as well.

Very true....love those laws

Quick question:
1)for a JBA 46 engine with good mixture setting, how long can a 190cc of glow fuel will last. Bought a 190cc tank from rcdhamaka and wondering if this would last for atleast 10mins.

It should. That has been my experience. However, sometimes extended starting problems can use up more fuel than you anticipated - watch out for that 

Meanwhile, have a look at some specific fuel consumption figures from OS

Approximate Fuel Consumption Rates at Full Throttle for             the Most Commonly Used Aircraft Engine Sizes                2-Stroke Glow   4-Stroke Glow   2-Stroke Gas   4-Stroke Gas    cu. in   cu. in   cc   cc 0.375 oz/min            25 0.5 oz/min            32 0.75 oz/min   0.32   0.5   24    1 oz/min   .40-.46   0.7   32    1.5 oz/min   0.6   0.9   50    2 oz/min   0.9   1.2   64    2.5 oz/min   1.2   1.6       3 oz/min   1.6   2       3.5 oz/min   2          Note that exact consumption rates will vary depending on the fuel:air mixture, type of fuel              used, nitro content, prop size, rpm, condition of the engine and atmospheric conditions.

Tables not clear. 

A 46 will use about 1 oz/minute

Here is the link

http://www.osengines.com/faq/faq-q900.html

http://www.osengines.com/faq/faq-q900.html

so with a full tank of 190cc this should give me around 6-8 minutes of flying time. thanks Sanjay.

Quick Questions:
1.Just bought 5lts of glow fuel from Ethiraj sir with 5%nitro. i dont think i can use up that in atleast 3 months. So how long can we store nitro fuel, i mean its shelf life.

2.I applied castor oil as after run oil, will it ruin the engine. Can i use WD 40 or do i need to buy after run oil. i will be flying every week.

3. Im unable to find the tuning manual for JBA 46 engine, so made 2 full turns from close and started the engine and leaned out until the engine won't sputter without glow plug, is this okay, can anyone please tell me the tuning of HSN in this engine.

4. without the glow booster it maintains idle quite good, but when i transition from idle to mid throttle it sputters and stops, but runs fine when i do the transition very slowly. and no matter how slow i transition from mid throttle to wide open, it sputters and stops. is this too rich or a faulty glow plug.

5. the engine is a bit old, so i suspect a faulty glow plug, when i connected the glow to booster it glows bright yellow and becomes too hot to tough     the outer, but doesn't glow completely. ie, 1mm from the outer side isnt glowing. it glows deep inside the plug. is the plug needs to be replaced.

6.Finally, its a JBA 46 engine and has a OS A3 plug. is this okay, or do i need some other plug. and i cant find the OS A3 plug anywhere online.

1. 6 months is OK.
2. If you are flying every week you don't need after-run; however I strongly advise it's use with Nitro fuels as these release a small amount of HNO3 on combustion. Don't use Castor Oil. If need be, clean with Methanol and lube with a few drops of thin machine oil like 3-in-1 or Singer Sewing machine oil.
3. You are doing it OK. After reaching peak, 'rich' it out by a 1/4 turn
4.Check your glow plug. Also, there is another screw near the carb in the casting of the engine block. Move this 1/8 turn at a time and observe the changes. But first check the plug
5. You can use OS # 8

Thanks a lot Sanjay sir, i found the A3 plug with spherehobbies.com
I am still awaiting a reply from lotushobbies.com for the landing gear.

Ganguly-da needs a few reminders

V2eagle sir i have a question wouldn't a flysky fst6 not be good for a nitro because of its reliability or you have changed your radio set.

Nitesh, A radio NEVER knew's what you are flying. What makes you think that Flysky is no good?
Again, everything is just electronics and anything can fail.

Sanjay Sir, a contact number for Ganguly sir would be good, ive planned to fly this week if i could get the landing gear by this friday.

AK.

Number on website

Sanjay Sir,

Replaced the glow plug with a new No 6 OS plug and yet experiencing the same problems with my engine.
this time i can move the throttle a little more than half and engine cuts out. is this normal and maybe i am trying to push the engine to its limits.

i use a 10x6 prop and 5% nitro fuel with synthetic lube.
normally i see engines dont quit untill WOT. is there any other issues with my engine.

and where can i find the low speed needle.
Attaching Pic. if im not wrong,
#1 screw is behind the carb and not shown in the pic and should be the Idle screw
#2 screw should be LSN
#3 screw should be HSN

what should i be doing to get a consistent run and to avoid engine cutouts.


Ashok.P

That is correct. Have you tried downloading the JBA manual?

The LSN should only be moved a very small amount at a time. If you cannot locate the manual, you can get some general guidelines from the OS manual.

Are you sure your main needle setting is OK? You should lean (reduce) till you peak out the RPM (can make out from the pitch of the sound) and then richen by about 1/8 to 1/4 turn

Once the engine is properly tuned, (a) it should not tend to cut off at any throttle setting  (b) it should not tend to cut off when moving the throttle stick fast  (c) should not slow or cut in all positions (aspects) of the model, i.e. vertical, inverted etc.

Got it sir. will try today . and do i need to richen or lean the LSN

Rich or lean depends on the behaviour of the engine when you suddenly increase throttle. Do have a look at the OS 46 AX manual, if you can't get the JBA manual. Useful guidance