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Author Topic: F2D FORA engine servicing  (Read 18671 times)
Yaroslav Melnikov
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« on: April 30, 2012, 03:07:21 PM »

Being a FORA competition engines retailer I get quite a number of requests to explain how to break-in F2D engines properly. So I just would like to focus on FORA F2D engines servicing. Since FORA doesn't include any instruction in their "box"  Cool all the service "instruction" is based on my own as well as the other F2D pilots' experience. If you have anything to add - you are very welcome, feel free to PM or send me e-mail
« Last Edit: May 30, 2012, 04:43:36 PM by Yaroslav Melnikov » Logged
Yaroslav Melnikov
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« Reply #1 on: April 30, 2012, 03:37:14 PM »

First of all want to focus on breaking in the new engine. Since inexperience pilots normally don't know what to start from I would suggest the following break-in procedure.

Engine inspection

1.
Inspect a new engine as well as NVA (needle valve assembly) for aluminum/brass bits. As sometimes FORA leaves these to the end user. First I would inspect the NVA for the small bits. Some people take the NVA off right away upon receiving a new engine and inspect it separate, but I would strongly recommend not to do it as the NVA is hot pressed to the crankcase and to remove it you would need a special tool, otherwise you may damage the NVA and the crankcase as well. What you can do - take the needle off; put a piece of silicone tubing onto the nipple side and air press a few times with empty syringe and then put some methanol (fuel) into the syringe and do it again with the methanol (fuel). Needles to say you have to do it in a good vented room and make sure you keep your eyes away and protected from the methanol coming out of the other side of the valve while you wash it.

2.
Take the back plate and the head nut off and point the strong water stream to the opened case (where the back plate is mounted), turning the crankshaft a bit to allow the water to flow through all windows in all directions - water should come out of: the exhaust window at the liner and the inlet window in the crankshaft (venturi).
   After all done, wash the engine in methanol or petrol (benzine) and leave it open for a few hours to let it dry out. Then lubricate it with oil, put back the back plate and the head nut on and you are good to go.
« Last Edit: April 30, 2012, 11:22:02 PM by Yaroslav Melnikov » Logged
Yaroslav Melnikov
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« Reply #2 on: April 30, 2012, 05:32:29 PM »

Setting the head clearance

The second step you have to do - setup the right head clearance.

From series to series and from engine to engine FORAs come with different head clearance. It doesn't mean it supposed to be like that as the liner and button head still have the same sizing/volume and they are made of the same material. I can only guess it's just upto the shims availability at FORA's stock or some market approach, or some other unknown reason.
However if you received the engine and the head clearance is relatively small it doesn't mean the engine is not gonna work, it will, but the smaller clearance means more power, but at the same time more stress to the engine's parts too and might reduce their life as well as the plug's (and as you know it's costly).

So first of all, after the engine's inspection is done I would recommend to deal with the head's clearance. For the outside temperature 20C and up, I would suggest to set 0.45mm (0.0177"). To do it you might need "Digital head clearance indicator" tool is sold in our combat store, or any other caliper tool to measure the gap between the piston's bottom and the bottom of bottom head.
After a break-in I would recommend to make 10-15 flights with that head clearance, then reduce it to 0.4mm (0.0157") and keep this clearance for practice flights. In the competitions you may reduce the clearance to 0.30mm (0.0118") or even less, but keep in mind - while trying to squeeze the maximum power and setting up the lowest head clearance possible, the danger the engine will start to blow off the plugs increases dramatically.

The head clearance mentioned above is applicable to the latest F2D FORA versions (come with 6mm muffler) and to the standard atmospheric pressure. As the higher the flying field's elevation is - the smaller head clearance will be needed.
« Last Edit: April 30, 2012, 11:27:39 PM by Yaroslav Melnikov » Logged
Yaroslav Melnikov
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« Reply #3 on: April 30, 2012, 07:25:14 PM »

F2D FORA engines break-in quite fast due to the piston specific shape (aka in-curved barrel).

The break-in

Normally the break-in involves only a few full tank runs.
I would recommend to do it as follows:

1.
One full tank on the ground, NVA setting rich

2.
One full tank flying LEVEL, NVA setting rich

3.
One full tank flying LEVEL, big loops NO SHARP TURNS! NVA setting - slightly rich

And you all set!

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Yaroslav Melnikov
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« Reply #4 on: April 30, 2012, 08:00:56 PM »

The fuel

It's well known since 6mm muffler FAI rule introduction in 2011 came up it caused a number of discussions as well as tons of advices how to minimize the 6mm muffler hole bad impact as using the standard FAI fuel it causes a massive carbon deposits in the engine.

Here is my own notes on this matter.

After testing a number of fuels I stopped with "Cool Power" 10% nitro. It contains 18% synthetic, and I add a bit of castor in there to make it 19-20%. With this fuel it doesn't make much carbon build-ups and the speedwise the engine is about the same as with FAI fuel.
Another good side effect of using this blend - no need to re-adjust the head clearance for the FAI fuel while in a contest, but would need a bit adjusting in NVA since oil/methanol/nitro components percentage are a bit different to standard F2D FAI fuel.

Course you might use some other blends, but to my experience you have to check the blends first for anti corrosion properties as the steel parts of your engine might just rust. So before using any other blend I would recommend to fill a small container with some fuel you intend to use, drop some high carbon parts in there (old crankshafts, old drill bits, bearings etc); keep it for about a week and visually inspect it if any rust signs show up.
« Last Edit: April 30, 2012, 11:33:24 PM by Yaroslav Melnikov » Logged
AdzNadz
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« Reply #5 on: April 30, 2012, 10:11:51 PM »

That's great advice Yaro, thanks.
I've only been flying F2D for a short time but I've been using my own mix
of fuel for practice : 10% cool power synthetic, 10% castor, 10% nitro.
Sounds like I can safely increase the percentage of synthetic.
Do you have any advice regarding cleaning of carbon deposits?
Cheers.
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Yaroslav Melnikov
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« Reply #6 on: May 01, 2012, 01:01:39 PM »

After run service

The fuel components are active to the engine's parts and might cause some damage, so it's highly recommended you wash the engine after your practice/competition flights.

As the base washer I would recommend to use kerosine (camp fuel). Kerosine is a good grease remover and has anti-corrosive properties
Add small amount to venturi, turning the crankshaft (not a full turn, just aka yo-yo turn) let the kerosine come into the crank case. Keep yo-yoing the crank shaft, put the engine nose up/down letting to penetrate the fluid as far as possible. Then putting keeping the engine nose down, yo-yo the crankshaft letting kerosine to come out of the engine. Do it again with the engine nose up - letting kerosine to come out of the exhaust window/the muffler.
Repeat the wash procedure 2-3 times, to make sure the fuel components are completely washed out.

After the engine wash, put a few drops of all purpose household oil into venturi, exhaust window/muffler and turn the crankshaft a few times letting the oil penetrate into all the parts of the engine.
As the all purpose household oil I use this blend:
"3-in-1 Household Oil"
http://www.canadiantire.ca/AST/browse/4/Auto/3/AutoFluidsChemicals/GearSmallEngineOils/PRD~0387807P/3-in-1+Household+Oil.jsp?locale=en
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Yaroslav Melnikov
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« Reply #7 on: May 01, 2012, 01:28:36 PM »

That's great advice Yaro, thanks.
I've only been flying F2D for a short time but I've been using my own mix
of fuel for practice : 10% cool power synthetic, 10% castor, 10% nitro.
Sounds like I can safely increase the percentage of synthetic.
Do you have any advice regarding cleaning of carbon deposits?
Cheers.
Yup, you can use any percentage of synthetic you want, but keep in mind regardless castor's negative side effect like massive carbon deposits it maintains stronger oil film that prevents the stressed engine's parts from damage. The other words it lubricates much better in high temp range due to some castor properties. So just don't use the clearance you use while the competitions and everything is gonna be just fine.

For the last two seasons I haven't faced really huge deposits in my F2D engines, that could stop me from flying and look into the way how to clean up all the black crap in there, as I've been flying synthetic fuel for practice flights. But from the guys have been using FAI fuel all the time, I've heard they use sort of automotive stuff that dissolve the carbon deposits. Perhaps you might look up in any automotive store near by. But again, make sure the dis-solvent you are going to use doesn't cause any damage to the engine's parts material like aluminum, carbon steel, chrome steel

What I would do if the worst scenario happened - I would just clean the piston's bottom (the part the carbon builds up the most). For that you could use a piece of extra fine sand paper (water resistant). Put a piece of that sandpaper on the piece of window glass, add a few drops of kerosine and keeping pressed the piston's bottom to the sand paper remove all the carbon with round moves aka drawing the circles with your hand. After the carbon is removed - wash the piston under stream of warm water with tooth brash and some soap. Dry it out, lubricate it with all purpose oil and you all set
« Last Edit: May 02, 2012, 07:43:44 PM by Yaroslav Melnikov » Logged
Yaroslav Melnikov
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« Reply #8 on: May 15, 2012, 08:07:54 PM »

Engine servicing while the combat.

You hit the ground badly - the engine is dug into the ground till the LE. The model has a minimum damage and is still flyable, but...
It happens some time while the combat and here is a good question comes up: what to do with the engine??? As it's obvious the engine is not gonna run if it's full of mud.

Here is what how I do it, so you could do the same steps:
1.
Dig out the motor/model  Grin
DO NOT TURN THE PROPELLER/CRANKSHAFT!!!

2.
Transport the model to the pitman position NOSE DOWN ONLY

3.
Keep holding the model nose down; clean the venturi with thin spring wire. If there is some fuel in the tank left - open the shutoff letting the fuel flow while cleaning the venturi to let all the crap come out of it.

4.
Keep holding the model nose down; Put a big amount of kerosene into the muffler and turn the crankshaft a bit letting the kerosine to come out of the venuri. Do it one more time blowing into the muffler so all the mix will blow-off of the venturi.

5.
Replace the prop and you are ready to go!

If there is some mud around the propeller base washer and on the crankcase - not a big deal. The engine will run good enough even if there is some mud penetrated under the base washer and into the nose bearing - no worries, after a severe ground hit you would need to replace the nose bearing anyways...

After the match do not forget to take the engine apart, clean all the parts under strong stream of water with tooth brush. Then inspect them visually if no small mud bits left inside. Then wash the parts in kerosene/benzine, lubricate them with oil and you are all set for the next match.

Make sure after returning back home you will COMPLETELY clean the engine. So you would need to take it apart again, this time taking both bearings off and do all the cleaning. What I do - just put all the parts (except piston + liner assembly) to a small jug with benzine (petrol) and wash them there.

« Last Edit: June 01, 2012, 05:23:33 PM by Yaroslav Melnikov » Logged
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