cessna 310 R

[anofly]

Might have a chance to fly a 310 R.
Reading manuals (thanks for links)
and looking at pictures.
when you start a 310 R you press a primer switch to the engine you are starting.
I cannot see or figure out what that switch does.
it is not on fuel diagram, etc
you have pumps off, select starter to engine you want to start, and then select primer switch to engine you are starting.
After it starts you select aux fuel pump to low..
What goes on while pump is off, starter is turning and primer is on to selected engine?
Thanks
I like to k now what is going on...

[Colonel]

Never flown an R, but on earlier 310 models it activated the electric boost pump for additional fuel priming.

I remember a friend of mine, pump died on one side, so he primed with crossfeed. Pumps are expensive!

God, so many decades ago. He's long dead, of course. Tore a wing off a homebuilt.

[anofly]

O k that makes some sense. it does say press starter button, then select primer to engine you are starting , after it starts it has you select aux fuel pump (that is selected off) to low.... it never has you select primer swtich to off or anything but select it to rright engine when you go to start that engine.

reading between the lines there are two speeds for the aux pumps, you can select low... but they go to hi auto when the mech pump fails ?...
lots to learn here.... or maybe better described as three settings ... off, low, on? on being hi?
help me... LOL

[anofly]

I promise to get a checkout... but I want to know something when i get there....LOL and I have had folks check me out that really did not know how the mechanics of the thing worked...

[digits]

Funny. I just flew a 310 for the first time a few days ago. I was wondering the same thing. The starting procedure in the book did not work for me. Not sure if that was due to a lack of pilot skill, or due to the aircraft maybe not being in optimal mechanical shape. I ended up starting it like I did with other fuel injected engines.

Normal start:
Mixture full rich
Props forward
Alternators on
Per engine (left first):
- prime, move throttle fully forward, check fi there is any fuel flow, immediately move throttle back and release primer switch
The manual has a caution not tuse primer for more than 2 seconds
- throttle open 1.5 inch
- press start button. don't be afraid to let go of the starter as soon as you think the engine is running. with 6 cylinders and 3 bladed props (in my case) there is quite some inertia that will get it to properly start even if you let go a bit too early. Pressing it too long could damage things, according to POH
- fuel pump low
Give the battery a minute, repeat for right engine.

Hot start:
Mixture full rich
Props forward
Alternators on
Per engine (left first):
- fuel pump low
- throttle fully forward until fuel flow is steady
- throttle half open
- fuel pump off
- mixture cut off
- start
- when engine fires, mixture full rich, throttle back to 1.5 inch
Give the battery a minute, repeat for right engine.


I'm open to adjusting this if anyone has a better suggestion. This was with an IO470.

[Colonel]

Remember, only fuel vapor burns, and 100LL evaporates really really slowly
compared to say car gas, esp at low temps.

A "cold start" in the summer (at 100F) will require a lot less fuel than a
"cold start" in cooler wx at say 20F.

There should be no problem with only priming before you crank, at least
in warmer temps. The problem is that after the first few revolutions, if you don't
get a start, that priming fuel can get pumped out - and then you're too lean - and
it's convenient to be able to add some more fuel while you're cranking, rather than
stopping cranking, priming, then cranking again.

Just don't bend the connecting rods. As Seneca College found out, you can
hydraulic lock a Continental with over-priming and bend connecting rods during
a start. They don't fail right away, so the idiot pilot thinks he got away with it.
The connecting rods fail later, in flight - generally on some other pilot - and punch
holes in the crankcase.

There's some arrogant future four bars, right there. I'm sure those guy are left
seat on some EuroTrashBus by now.

I do wish that in the 80 hours of CPL ground training, some mention could be made
of elastic vs plastic deformation. You know. Connecting rods. Wing spars.

[Colonel]

PS Kickbacks during start. Routine with Lycomings. Expensive with Continentals.
Anyone know why?

Pop quiz for the class: for that matter, why do kickbacks occur?

No, I'm not talking about Brian Mulroney in a New York hotel room, getting $500k
in cash for every airbus that Air Canada bought.

Talk about the different magneto configurations on Lycoming vs Continental.

Note that my three Lycoming factory engines have no impulse couplings on any
of the magnetos. How do they start?

https://www.donmaxwell.com/shower-of-sparks

[anofly]

the manual clearly says to
' get it spinning, then hit primer to side you are starting...then release starter when it starts, and turn fuel pump to low... " then select primer to other engine when its spinning...

[digits]

the manual clearly says to
' get it spinning, then hit primer to side you are starting...then release starter when it starts, and turn fuel pump to low... " then select primer to other engine when its spinning...

I know. I am just saying I couldn't get it started that way. And fuel was just pissing out after the failed starts. Let me know if it does work for you. And how long you prime. Short squirts or one big one etc.

[Big Pistons Forever]

The big bore Continental starter adapter was probably designed by a British engineer. It is a good example on how do something simple, the hard way.

Lycomings have Benedix starters. One little gear directly driven by the starter engages a big ring gear bolted to the crankshaft. Pretty fool proof. The only thing that usually goes wrong is the little gear doesn’t fly out to catch the ring gear when you engage the starter. A squirt of LPS and you probably be good to go.

The Continental starter has a shaft from the starter which engages a wind up spring which grips a drive shaft which turns the engine over through a 90 degree gear set.

What can possibly go wrong ? Let me count the ways

1) The spring gets weak and so won’t tightly grip the drive shaft, which leads to

2) The spring slipping on the drive shaft which causes spalling, and twisting of the spring, which leads to,

3) The spring breaks and then pieces of the spring drop into the engine crankcase, which leads to,

4) If you are unlucky enough to actually start engine the broken springs pieces get ground up after the engine starts and contaminate and damage engine bearings and other important internal parts, ruining the engine. If you are lucky and the engine doesn’t start then if all of the bits can’t be fished out at the starter area you get to send your engine to an engine shop to have your engine disassembled to get them all out.

5) And as a final fuck you Continental had to add a viscous dampener to the starter adapter on the GTSIO 520 engine used on the Cessna 421 and a few other airplanes. Failure of this dampener will result in catastrophic engine vibrations and engine failure


To avoid a very expensive lesson. Do not try to start the engine without having the starter adapter looked at if:

1) The engine suddenly starts to be noticeably slower rotating, and you know you have good battery voltage

2) There is a delay from when you press the starter and the prop starts turning

3) You hear a noticeable metallic clunk when you engage the starter

4) The engine kicks back with the starter engaged

As for starting the C310 I do it the same way for all Big Block Continentals. Cold, Prime until you see the second rise in fuel flow, then stop prime and hit the starter

Hot, I just start cranking, if it doesn’t start give it a blip of prime. What usually happens is it will fire right away and then die, so you have to be ready to give it a blip of prime as soon as it starts to die and it will pick right up.