Engine tuners' guide?

Some time back there was some discussion about creating an "engine tuner's flow chart" much like the stunter flight trimming flow chart. Did that ever come to pass? I think it's a great idea and just as valuable as the flight trimming flow chart. There are so many interacting variables I never know what effects what...

Ill start this one off..

Step 1: start engine -> if engine fails to start, see step 2.

Step 2: Retry Step 1.

Like all instruction manuals.. Useless

>Ill start this one off..
>
>Step 1: start engine -> if engine fails to start, see step
>2.
>
>Step 2: Retry Step 1.
>
>Like all instruction manuals.. Useless :)
>
>
>

Ron B.
F4Fguy

Pretty good,but not comprehensive enough to be really useful.It should include:

(1)start engine
(1a)Grab by venturi throat and choke to death or until fuel runs out the exhaust.
(1b)Flip until arm is tired.
(1c)Realize thing on ground is battery clip.
(1d)Replace battery clip on plug.
(1e)Flip again.
(1f)Yell in pain at finger smacked by prop.
(1g)Drain excess fuel from engine.
(1h)Repeat 1b,1c,1d,1e.
(1i)repeat 1a through h until legs and back spasm cause extreme pain.
(1j)Exchange places with flying buddy,who will start it with one flip.
(1k)Fly
(2)Repeat step 1.

>(1)start engine
>(1a)Grab by venturi throat and choke to death or until fuel
>runs out the exhaust.
>(1b)Flip until arm is tired.
>(1c)Realize thing on ground is battery clip.
>(1d)Replace battery clip on plug.
>(1e)Flip again.
>(1f)Yell in pain at finger smacked by prop.
>(1g)Drain excess fuel from engine.
>(1h)Repeat 1b,1c,1d,1e.
>(1i)repeat 1a through h until legs and back spasm cause
>extreme pain.
>(1j)Exchange places with flying buddy,who will start it with
>one flip.
>(1k)Fly
>(2)Repeat step 1.
>
>Ron B.

F4F Guy,
Not to make light of Ron Hofacker's original post, but you have absolutely nailed this one the head!! If this isn't the most accurate list as to what ACTUALLY happens when you get out to the flying field, then I don't know what is. We can make all the engine starting flow charts we want to, but sooner or later, EVERYTHING SINGLE THING ON THIS LIST WILL HAPPEN!!! Further more, it will HAPPEN EXACTLY IN THE ORDER YOU LISTED!!!

Milton Graham\Proparc
>

"I don't know about this tuned pipe business. I practiced on that thing until my lips turned blue, and I still can't play a stinkin note."
"Homer J. Simpson"

Ron,

While the humor is, ah, well, humorous, it's not really answering your question. I don't think anyone has done anything about it since the original discussion.

Ron,

This was just too great an invitation for fun...

Actually, most manufacturers include usable instructions for starting their engines nowadays. You have to read between the lines sometimes, tho.

If instructions say prime with just a few drops, or choke fuel to the spraybar AND NO FURTHER, the engine probably floods easily and is a bear to clear from the condition. If instructions say choke until the engine sounds wet and gurgling when you flip the prop, it needs to be wet to get going. Some give very specific instructions about first-start needle setting -- go with that for starters.

But, basically, an engine needs:

Fuel

Air

Heated glow plug (spark or diesel are different...)

... in reasonable proportions, then a quick enough flip to get it going. All else is a box of bandaids to fix one of the above not being quite correct.

Flight settings are another bag entirely -- I doubt there can be any universally applicable way to summarize that area.

Yes I apologise, and I bow down to the third thread, its much more comprehensive.

In a serious nature, a tuners flow chart is difficult to write to the point where it is easily followed by unexperienced people.

With the trimming flow chart, Although well written, was basic from the perspective of. If Model does A: try step B.
I say this will FULL RESPECT of the author, and I personally used it many times, the point im trying to make is :
If the wing flies high, 9 out of 10 times you can solve it with a Flap tweak, or tipweight. ( Simple answer I realise but aircraft are easier to trim will less variables )

However, with an engine there are MANY MANY variables.
Engine wont run properly?
Where would you start? - Blocked spray bar, faulty glow plug, Hole in the tank, dirt in the fuel, Faulty fuel batch, incorrect fuel mix, incorrect glow plug, perhaps try pressure, prehaps no pressure, Head shims, gaskets, pipe length ( or no pipe length ) tank position not correct, venturi size to small / large, prop size.

I know its complex heaven knows everyone who flies stunt has dealt with there own engine demons.

Perhaps what the original author was asking for was a basic engine tuners guide?

Say for example, Engine runs faster inverted than upright, Change the position of the tank which way.

What basic RPM should a 11 x 5 .35 Fox be set at?

Is this what you were trying to suggest?

Everyone sets up there equipment differently, so it would be hard for person A to say for sure what the solution to Problem X would be.
Its a case ( like most things ) If it works for you try it.

>
>Perhaps what the original author was asking for was a basic
>engine tuners guide?
>
>Say for example, Engine runs faster inverted than upright,
>Change the position of the tank which way.
>
>What basic RPM should a 11 x 5 .35 Fox be set at?
>
>Is this what you were trying to suggest?
>

Yeah, that's what I'd like to see...

Well, let's see where this goes.

1. Get to know the engine well on the test stand. If it's new, break it in as per the correct method for the type. ie: ABC/ABN/ACC; iron piston/steel sleeve; ball bearings/ring..... Install a NEW plug for the first flights after break in. A new glow plug is cheap compared to a stunt ship.
If it is used, still put some runs on it with the fuel and prop you intend to start with.

2. Get the procedure for easy starts on the stand. Does it need a wet prime? etc..

3. Once it's in the plane, do a couple runs to see how the whole system is working. Any leaks? Erractic engine might be because of fuel line or tank problems if it was runing good on the stand.

4. If it is a classic 4-2 engine, set the outboard wing on your foot while the engine is running and rock the nose up. If set correctly (or near) it will break into a 2 stroke. Flip the plane upside down and see if the engine is running about the same, or a little faster, with the plane inverted.

5. If the engine goes rich inverted, shim the tank up towards the top of the fuselage with the plane in a normal attitude.

6. If it goes lean inverted, lower the tank towards the bottom of the fuselage.

7. If a 4-2 engine, the setting for initial flight will probably be a slight "cackle" where the engine is in a very hard 4 stroke and just bumps a 2 stroke.

8. If the engine doesn't break into a 2 stroke under load, lean the needle a click or two. If it goes into too slow of a 4 stroke after launching, lean it a little.

9. For the wet 2 stroke run, the needle will be set to the point that the engine is just running a smooth 2 stroke going in from rich.

10. If the eninge "sags" while running a wet 2 stroke (rpm slows when manuvering, top of loops, etc.) then open the needle a click or two.

11. Once you have the engine running where it seems to be happy, use props and nitro to get the ship's speed where you and the ship are comfortable.

It is always a "cut and try" experience with a new combo, and this barely scratches the surface.

Jump in guys!!!!!
Bill <><

LAST EDITED ON Jun-26-04 AT 09:08 AM (CDT)
 
What He said.

Its very hard to say SET AT THIS RPM

Because its all personal preferance.

But listen to the engine, get a feel for what is a smooth 4-2-4 and what isnt.

Dont be afraid to try new plugs/fuel ratio/props ect. Only through change will you find out what works best for you.

Just if all else fails go back to what you know works.

" if it aint' broke dont fix it - but fiddle all you want "

LAST EDITED ON Jun-26-04 AT 12:20 PM (CDT)
 
Bill and PJ,

I think that's what most of us do. Put the engine on the test stand and after basic break-in (usually as specified by the manual that came with the engine), start experimenting with what procedures are needed to reliably start it. How much prime, what plug, fuel, etc. Once the procedure is mostly down, it goes in the plane and is further refined.

One of the problems I had for years was changing powertrains every year (it seemed). I'd just about get the process of figuring something out and then change to the latest and greatest and have to learn all over again. This didn't make for very consistent engine runs and my scores reflected that. Over the past 3 years I've stuck with one system and resisted the temtation to change to the lastest "in" setup. And surprise, surprise, I've been getting pretty consistent and repeatable flights. Does wonders for you ability to think about something else besides the powertrain.

LAST EDITED ON Jun-26-04 AT 12:28 PM (CDT)
 
This is agreat start! I guess I'd like to see this as an add on to the flight trimming chart... not so much on how to break it in or start it but how to trim total flight system.

Thanks:)

Hi Ron; I think what would also be useful would be the effects of adding or removing head shims, and changing ventura sizes. Generally I think one effects the other to some degree.

>Hi Ron; I think what would also be useful would be the
>effects of adding or removing head shims, and changing
>ventura sizes. Generally I think one effects the other to
>some degree.

Yeah... There is all this good knowledge out there about how to set up and adjust the set up of your engine to achieve the kind of run you want. It would be great to pull it together into a single spot for us beginners to start from. fuel tank position, props (pitch and diameter), fuel nitro/oil content, plugs, head shims, venturi size, even atmospheric changes like temperature, humidity and altitude...