HobbyKing.com New Products Flash Sale
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Old Oct 06, 2012, 08:38 AM
SBP
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brace, the stick from Hobby King looks like it would be a good choice for me also.The price is good, I won't feel so bad if things go wrong. If I order today I'll have a couple weeks to work with the engine before the plane arrives. Thanks for the info. Bruce
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Old Oct 06, 2012, 09:41 AM
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Quote:
Originally Posted by SBP View Post
brace, the stick from Hobby King looks like it would be a good choice for me also.The price is good, I won't feel so bad if things go wrong. If I order today I'll have a couple weeks to work with the engine before the plane arrives. Thanks for the info. Bruce
No worries Bruce, I had a good look at the model before I went back to work and it is pretty much an exact copy of VQ's version, so it should fly well. Takes a standard HK 10g servo so you can keep the build cheap.

Glenn
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Old Oct 09, 2012, 11:19 PM
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Look what is on our favourite online retailer Hobbyking.
http://www.hobbyking.com/hobbyking/s..._Ignition.html
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Old Oct 10, 2012, 02:46 AM
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Ya I saw that. After all the headache NGH got from this engine with most of us not being able to run it successfully without changing parts. Now they are just going to destroy their name since Hobbyking will sell loads of these engines and the Hobbyking customers will rape this product on all the online forums. Unless Micheal has change over the carb and pump.
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Old Oct 10, 2012, 03:14 AM
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Maybe Michael is dumping the 9cc anywhere he can and probably they`ll move pretty quick so he can disapear into the sunset before all the disatisfied customers surface and he wont be left holding any .Not a bad business move if its true . I surley hope not as I would like to get a trouble free version some day .I doubt that will happen though ( the trouble free version that is ) . Cheers and the pope has put his crystal ball away for now .
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Old Oct 10, 2012, 03:21 AM
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Feeling a bit annoyed after all the work people have put in let alone money, to have this sold cheaper with out the problems fixed is a bit of a slap in the face. I hope prospective buyers will look at this forum and see what they are in for. Oddly enough I would buy another and at the marked down price it makes it worth it for all the mods that have to be done.
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Old Oct 10, 2012, 03:38 AM
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You have to be abit concerned when the average modeler knows more about his engines then he does ! Hes good when it comes to replacing the odd broken conrod but the carbs got issues he wont deal with . Cheers the pope
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Old Oct 10, 2012, 03:56 AM
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Well even the conrod is a debatable issue as has been posted before. Could have easily been a much better design. Will be interesting to see what his next incarnation will be. Still think I may buy another and throw a walbro on it for fun. I have a spare carb in the shop and it would take no time at all to do it. Will have to give it some thought.
Note HK will not allow me to post
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Old Oct 11, 2012, 09:26 PM
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Wow! HK is selling it now too. HK is sort of the big hobby retailer in the Far East areas, similar to Tower being the big retailer in the USA. But that price makes me want to build a twin engine plane with these engines. Especially now that I have them figured out pretty good.

In one way this is good as the volume goes up for increased production. But on the bad side it means they are alienating their dealers too. That could be bad actually, the dealers may all give up on it. I doubt that the designer had anything to do with it, but it was the ones with the money backing him that went with the deal with HK.

I am not sure if many people are having problems as we don't normally hear from the folks who are successful. We only hear from the ones having problems and needing help.

I was fiddling around with a engine using a Jett tuned muffler on it. It turns some pretty wicked sounding RPMS with it too. But it was sort of scary coming up on the pipe so to speak, so I was running it as rich as possible too.

But it was most interesting in when I was taking pics, I was trying to catch the engine spitting at idle and I managed to get a good pic of it doing it. It does show about how long to make a intake stack to reduce it too. I am trying to figure out a way to show the droplets better. What happens is the droplets come out of the fuel standoff vapor cloud (you can see the ghostly shape of it in the pics too), get sucked in towards the base of the propeller and then riding on a thin layer of air near the blade surface get thrown back towards the rear. There is something of a reverse air flow at the base of the propeller, next to the spinner. The propeller blades are not oily, so the fuel droplets are not touching the blade. The droplets seem to aggregate some as well and get larger when being slung back. I need to find a high speed digital camera so I can better record the spitting and how the droplets travel.

I forgot to mention that the spitting happens with all of the engines, not just this one. You can feel the cold droplets on your hand when you have it behind a engine on the test stand and are running it too. I have some engines that build up a nice layer of varnish deposits on the front of the engine and muffler from being used a lot too.





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Old Oct 11, 2012, 11:05 PM
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Oh dear what have I done. Just bought another motor from HK. Well having so much fun with this one and getting a few more ideas about improving the motor, I just had to go one more
Talked to the local dealer here and he was surprised, fortunately he has no more stock of complete motors but does have plenty of spares, so that is a relief.
Earl, would a short extension on the carb body like a velocity stack, say 12mm, make a difference on the fuel spitting out and pooling at the top?
Glenn
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Old Oct 12, 2012, 05:48 AM
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Yes that was what I was thinking too. Maybe 20mm with a angled cut on the top would be better too. It would serve as sort of a air scoop. But to catch any droplets trying to escape.
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Old Oct 12, 2012, 06:03 AM
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Yes we are thinking along the same lines, I have a length of aluminium pipe that is the right diameter to fit over the carb mouth. My idea was to extend it sufficiently so that the vapour bubble was enclosed and all fuel from the needles were kept in the system. The thought was to try and remove that stutter from intermittent gobs of fuel entering the engine and the vapour bubble from being pushed about by the turbulence of prop etc. 20mm with a good bevel would sound about right.
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Old Oct 13, 2012, 03:36 AM
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Hello to everyone, i follow this thread for a while now because i like idea for 9cc gas engine. I would like to use it on my P- 51 mustang pts - hangar9. The think is that i read so many negative comments about this engine and i'm not sure this is a good investment. Can some one who have experiences with this engine in short write actual problem and what i need to do for this engine to work as it should do....Thanks in advance !!!!
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Old Oct 13, 2012, 05:23 AM
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Ok well I guess I have a bit of time at present so I will write up about what I have done to bring my motor to a point I am happy to fly.
This is mostly a collaboration of some very smart people who have contributed to this forum and I have simply taken advantage of that knowledge implementing it on my engine. I am not an engineer and I may use terms that are not correct, please don’t shoot me 
1. The motor is not a plug and play from the box, you will need to do some work and buy some more items.
2. First is I would take off the back plate of the motor and replace the threaded pressure nipple with a larger one. 8/32 fitting from Dubro seems to be the popular one and this will require drilling and re-tapping.
3. The pump/regulator should really be pulled apart and serviced with a Walbro K20-WAT kit, this will replace the diaphragms, gaskets, metering lever and plunger needle. I would also have a look at the faces of the unit where the gaskets seal on and see if they are smooth. If not then smooth them off by putting some cutting paste on a sheet of glass and run the face over it in a gentle figure eight motion to bring the surface smooth and level. I used a fine stone at first and while this worked it created a slight curve in the face which I later had to remove. The new gasket and diaphragm will handle the newer fuels and not get out of shape quickly.
4. If you are really into servicing the pump/regulator then you can also replace the metering spring with a Walbro WYJ 98-3160-7. I have not done this yet but intend to, reading on the forum it will change your needle settings from the manual.
5. I have used 1/8th Viton tubing for the pulse line to minimise loss of pulse to the pump/regulator. I have seen some use a brass tube with tygon at each end to do the same thing, not a bad idea but you would want the tubing to be barbed.
6. When putting the motor on the test stand, or plane, have the pump/regulator on some sort of foam mount to absorb vibration. It has to be positioned as close as you can to the carb, allowing for the exhaust pipe, 80mm is the recommended maximum distance.
7. Fuel tank can be where ever you find space and height is not an issue.
8. When fitting the prop, be sure the collar which has the earth magnet for the hall sensor is in the correct position. It can be rotated and fitted back in place 180 degrees out. I am sure all of us have made the mistake but it is easy to check, rotate engine until tdc and sensor will be near the magnet.
9. Make sure all your fuel connections are air tight and secure.
10. Fuel mix is 20:1 don’t even think about 25:1
11. Without the new spring on the pump/regulator my needle settings are LSN a touch more than 2 1/2 HSN just under 1. When you first start it I would put the LSN at 3 and the HSN at 1
12. Be sure you are only supplying the correct voltage to the ignition unit 4.8v

13. Before starting with the ignition off rock the prop back and forth to pump fuel up to the carb. Start the motor with about of the barrel open. If it does not start straight away you may need to open it more to get more air into the motor. Starter motor required.
14. Adjust your needles to best setting. I have so far with an engine that is still running in, achieved 2500 to 10500 rpm with a 10.5x6 APC prop
15. Motor runs nicely but does sputter a bit and definitely spits fuel out as the carb is very basic and only just does the job. Work in progress with improving the performance.
16. NB. I have had problems running the motor inverted, suspect it is the carburettor and for now will run it upright. My next experiment is to change the carb to a more refined one to see if that gives better control and to fit a small velocity stack to protect the vapour bubble, which will also hopefully contain some of the fuel spitting.
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Old Oct 13, 2012, 06:36 AM
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That is a good write up for it.

I would also suggest to use a really good synthetic oil such as Stihl Ultra or Amsoil Saber Pro. These oils add a lot of protection by helping to lubricate the engine, should something happen and it goes lean in the air. It gives you some extra time to cut the throttle and land. But don't try less oil than the 20:1 ratio. The mineral oils will carbon up the little engine faster, foul the little tiny spark plug, and don't provide much critical lubrication in a lean run where you have only a few seconds to cut the throttle before something breaks.

It is also important to know that the electronic CDI unit has a 6.0v maximum to it. So do not try running a Nicad or NMH battery pack with more than four cells in it. The 4.8v battery pack works very well and higher voltages than these packs only increases current draw without improving performance. If you try using a voltage higher than 6.0v it will destroy the CDI unit. This would include LiPo or LiFe two cell packs and voltage regulators set for higher than 5.0v.
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