Sad

Good time to build!

Ok, so I am still facing problems with my engine. The engine runs fine as long as the starter battery is connected but stops the moment it is disconnected. If I disconnect the battery and connect it again very quickly, the engine splutters and then starts again.
Will be checking with a new glow plug, but are there any other suggestions?

Plug.

Planning on converting the stick to electric.
How would the following setup be?
The AUW of the plane currently is around 350g and removing the engine and fuel tank will save around 120g.

http://hobbyking.com/hobbyking/store/__19034__Turnigy_Park300_Brushless_Outrunner_1600kv.html

http://hobbyking.com/hobbyking/store/__11899__Turnigy_nano_tech_850mah_3S_25_40C_Lipo_Pack.html

http://hobbyking.com/hobbyking/store/__2163__TURNIGY_Plush_25amp_Speed_Controller.html

6x3 APC Prop

My main concerns:
>I would like around 10 minutes of flight time.
>As the plane was not initially designed for electric, it has no ventilation, hence the 25A ESC even though the motor will only draw 7A (I would prefer not having to cut holes now, as the build is complete)

I have referred to the follwing site for calculations, and it shows that I should have a little over a 1:1 thrust to weight ratio.
http://www.ecalc.ch/motorcalc.htm

Your model is heavy - as per plans it should be 5 1/2 0z or 156 gms. I don't see any significant weight gain in switching to electric, if that is the reason for the shift.

I would suggest a slightly more powerful motor, about 110 W so you could swing a 8*4 or 7*4 (nearest available) SF prop  at about 1500 KV. This will give the thrust needed, which will be required at lower throttle. Select the ESC & Battery to suit.

If I recall correctly, the main problem was the engine cutting out. Maybe try 10% Nitromethane?

BTW, HK shipping is taking about 5 weeks nowadays, and they have again stopped shipping LiPos by Airmail 

Sir, could you suggest a motor?
I'm coming back on the 20th of December, so if I order in the next few days, hopefully it should arrive by then.
Also, I am ordering an Accucel 6 charger as well, so I might be able to get the total weight of my package around 1 kg and then use FedEx

How about this:

http://hobbyking.com/hobbyking/store/__27289__Turnigy_2205_34_1500kv_Brushless_Motor.html

Seems like this motor should be fine.

Maahin, do also give a thought about your next two models after the La Stick. You buy a motor, it is not just for one model. You do want some versatility too.

eg I have a 2826-1400 & a 2836-1400. With these I have a whole range of builds open to me, including the entire FT range, the Avispad family, and several ARFs, balsa kits and foam ARFs. Do give this some thought

Would the 2826 be too big for this plane?
Also would the 2826-2200kv be able to turn a 7x4 prop??

Nothing can replace the pleasures of flying a 1/2A Glow.

I would recommend don't loose the battle with Cox. if it has a good compression it is one of the most reliable engines to start. Least faults. Starts every time before the fourth flick. I use a spring starter.

Ok if your engine has good compression then there are only three problems for starting problem.

Glow Plug, Reed valve and 'O' Ring of the needle. If your engine is starting well and running with booster then last two problems are eliminated. The Problem is only glow plug.

Now open the glow plug see that the filament is intact and clean from outer tip till inside the base. Since engine unused for long, chances of debris are high. Thinned out filament due to long use also can cause such problem. This you check under a good light condition outdoor with preferably a lens. Clean if any debris are present with soft (one - two) bristle. Compare with a new glow plug of any type if you are new to glow. if possible Replace with a new glow plug if you can source it.

Hobby King has the replacement glow plug

Sir, I did clean out the engine with methanol from inside. The glow plug is not blackened from anywhere and glows bright. I have an OS Glow plug adapter for the cox as well. I used that with a No. 6 Glow plug from my OS engine. With this glow plug, the cox did not quit, but it didn't seem as if it was running at full power.
I am definitely not giving up on the engine, just keeping it aside for now. Besides, there are other reasons why I want to shift to electric.
>Firstly since the plane has come out very heavy, I'm not sure whether the cox can take it or not. Even if it can, it would not glide very well and thus landings would be very hard since all landings will have to be deadstick.
>Secondly, and this is one of the main reasons,  I would like to take this plane to college with me, and hence electric would be much easier.

If you are using Adapter you are likely to have a variation in compression either too high or low. You are required to adjust by increasing or decreasing number of Copper Shims. to get Optimum Compression and performance.

Good Luck.   

Sir, I have 3 gaskets, I tried with all possible combinations. I got the best results with 2 gaskets, but wasn't impressed.

I am using fuel with 20% castor oil and no nitromethanee. Although many people say that Cox engines run just as well without nitromethane, I think I will have to add atleast 10%. I remember with the freeflight that I made. Even then the engine wasn't starting, but at the time I was using the original glow head and did not have even a single head gasket (dropped it somewhere in the field  ) hence I was losing a bit of compression.
Adding a drop of nitro to about 100ml of fuel and then using that fuel solved the problem.

Cox recommends Nitro content of more than 15% say close to 20% for good power. Even though cox starts and runs as well without Nitro definitely there will be a drop in performance.

What is the Max RPM and on what prop size? Only RPM can give you idea and an estimate of power achieved.

Cox is too small an engine to estimate power by feel of thrust or visual or gauging by hearing, although with experience you can.

If you are able to achieve an RPM of more than 12000 with 6x4 or 13500 with a 5x3 two blade or three blade then its is good since in air it will pickup RPM. with good nitro you can reach RPM close to 16000 and with better design improved engines you can reach 18000 RPM.

Cox Surestart can easily give a thrust of 200-250 gms of which is very good for a model of AUW 350gms.

Guys have flown a good gliding models close to 1 KG with cox.

I'm using a 5x3 cox prop. Though I have no way to measure RPM

Sent from my GT-S7500 using Tapatalk

If your engine does not peak High RPM more than 13500 then 5x3 is a problem for thrust.

Ready for maiden once again.........
This time with 2826-1400kv motor turning a 7x4 prop and a 950mah nano tech battery.
Setup draws 14 amps at full throttle. Thrust does not seem to be a problem.
I haven't measured the AUW as I don't have a scale but I'm assuming it should be around 350g.

That looks awfully nose heavy , and overweight too.

- at least check your cg before you commit

On the contrary, it should be a little lighter than it was with the cox.
Also, with the cox, it balanced perfectly on the main spar, now it balances slightly behind the main spar.

I really like the color of the plane thats good !!!

Wanted to go for the original stick look with the black cross on white, but didnt have white or black monokote. Only had a scrap of orange left.

Maahin use vinyl, i will get some for you to the field on sat