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Tricks of the trade operating IO-540s?

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Tricks of the trade operating IO-540s?

Old 21st Sep 2022, 23:50
  #21 (permalink)  
 
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Originally Posted by lucille
+1

Iím amazed how how anyone 40 years ago without access to the internet ever managed to start an engine.
They (we) had paper magazines..


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Old 22nd Sep 2022, 03:41
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Idling for 5 mins or so to run down the turbo speed was the go.
That’s a persistent furphy. The end of the landing roll is the point at which an engine (and its turbo, if fitted) will usually be coolest. The taxi afterwards and any stationary idling just warms things up.



On a ferry of a Bch. A36 WA to Qld I went in to Coober Pedy for fuel. It was 40 degrees OAT. I faced the '36 into what wind there was and did the refuel and had my lunch. On shut down I opened both cowl halves so that the hot air around the engine could dissipate.
It worked. Half an hour later I buttoned up the cowl halves and the donk started at first try. No boiled fuel in the fuel injection lines.
A good one for young pups to remember and use.
That worked because the heat-soaked engine driven fuel pump (EDP) was cooled, not because the injector lines were cooled.

The primary cause of hot start problems on normally aspirated CMI 520s/550s is the vaporisation of fuel in the heat-soaked EDP (bolted to the back of the crankcase). That’s why on some aircraft with those engines the most effective hot start procedure involves running the electric fuel pump for a minute with the mixture set to ICO. A bunch of lovely cool fuel is pushed through the EDP then turned around by the FCU back to a fuel tank.

I say on ‘some’ aircraft because the electric fuel pump is an airframe component, not an engine component and not all electric fuel pump systems are the same. For example, different model Bonanzas have different fuel pump systems. Mine had a switch that had only two positions: ON and OFF. The pressure out of that pump was so high that it ‘overcame’ the FCU in ICO. Running that pump for 60 seconds was a ‘bad’ idea. Other models have three positions: OFF, LO and HI. The ‘LO’ position is ideal for use to cool the EDP before a hot start. And then there can be differing EDPs between the ‘same’ kind of engine…

All of which is to highlight, once again, the fundamental importance of knowing the specific systems fitted to the specific aircraft you are flying.

(I always opened the cowls on my Bonanza after flight, for the earlier stated reason: To reduce the baking of the in-cowl components. And to have a nosy around - I stopped being surprised at the number of tools, cable tie tag ends, washers, nuts and bolts I’d find. It freaks me out that I can’t do that kind of inspection easily after each flight on the aircraft I’m currently flying.)

For those who think manufacturer’s manuals don’t contain any bollocks, think again.


Anyone who has a real interest in the safe and efficient operation of aero piston engines would be well-advised to do the APS course. (Disclaimer: I have no direct or indirect pecuniary interest in APS courses.)
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Old 22nd Sep 2022, 15:29
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I used to fly bank runs on 55/58 Barons and Navajos. Lots of hot start turn arounds at the intermediate stops. I read the manuals, and found the Baron start sequence worked really well on the Navajo, and the Navajo start worked really well on the Baron.

Navajo - Open throttle, Idle mixture, run the fule pump for about 15 seconds. Pump off, Inch of throttle, mixture up and back (to note a blip of fuel flow), then start. Engine would catch in a half turn or so.

Baron - Mixture rich, quarter throttle, left hand on boost switch, turn engine and 'Blip' the high boost once or twice while the engine turned over. Engine would catch in a half turn or so.
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Old 22nd Sep 2022, 18:48
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I used to fly a PA32-300 with a IO-540 for a parachute centre. Generally, I found hot starts (engine only shut down for a few minutes) easy, as were cold starts. The luke warm starts, as it were (frequent as it matched the time for the meat-bombs to repack) could be a bitch to get right on an (English) summers day.
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Old 25th Sep 2022, 02:52
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[QUOTE=Mach1Muppet;11299320 GA8 Might Help![/QUOTE]

Congrats on the gig :-). Tips and tricks do vary depending on the operator however!

If it's a KNx registered GA8, then being a young single male, shaving your head and willingness to work 80 hour duty weeks (literally no exaggeration there), you're already off to a very good start and you'll do well.
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Old 30th Sep 2022, 09:34
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Originally Posted by Mach1Muppet
Hey All, Thanks for all the replies! GA8 Might Help! Bosi72, couldn't have done it without your help mate! Cheers LB, will get in touch with him! 172heavy and Konev thanks a lot, pretty happy with my bold face recollection of the procedures, will make sure I never forget them!
GA8 is very much what i said, im not being sarcastic or trolling put the throttle forward and leave it there. lean to suit in the climb, once at cruise alt and speed bring RPM back to 2400 and lean to suit (i get around 55 at 7000+ feet) For the descent, dont touch the power till you start getting close, no need to baby it down, its not a io520. For starting, if cold climate (sub 5 deg C) 4 seconds on primer, if warm climate but cold engine a tad less and it will start happy as. for wam/hot starts. prime for no more than 1 second and it will go after 3 or 4 turns. Biggest thing for the GA8 is balance. it takes two 86kg adults in the back row to perfectly balance a single 86kg pilot (2 blade prop)
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Old 30th Sep 2022, 09:44
  #27 (permalink)  

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I just swore at them until it started out of fear. That worked.
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Old 4th Oct 2022, 08:19
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nahhhh mate, it was KNE's starter I swear.....
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Old 4th Oct 2022, 10:42
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I just swore at them until it started out of fear. That worked.
Ahh - the tourette's starting technique.

Same technique works for gusty crosswind landings.
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Old 4th Oct 2022, 12:12
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It’s been a while and I’m really guessing and delving into the memory banks but…….

Wasn't there a high speed starter motor you could slap on the 540 on the Chief?

I’m sure I have memories of this and it making starting a breeze???
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Old 4th Oct 2022, 23:27
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Donít let the prop drive the engine , geared prop , preferred power running from engine to the prop ?

Thanks for the technical correction .

Last edited by KAPAC; 5th Oct 2022 at 00:22.
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Old 5th Oct 2022, 00:09
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Wouldn’t be too many aircraft in the GA piston charter business these days with gearboxes.
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Old 5th Oct 2022, 09:51
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What is the indication for the pilot to prevent the prop driving the gearbox?
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Old 5th Oct 2022, 10:29
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Originally Posted by Runaway Gun
What is the indication for the pilot to prevent the prop driving the gearbox?
If you have a piece of cotton on the windscreen indicating slip and skid, in normal operations the piece of cotton will be blown generally aft from the point at which it's anchored. However, when the gearbox of that aircraft is being driven by the prop, the piece of cotton will be blown generally forward from the point at which it's anchored (and the indications will be reversed). A bit like backcourse on ILS etc.

Last edited by Lead Balloon; 5th Oct 2022 at 22:53.
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Old 5th Oct 2022, 13:29
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I have worked on and flown many IO540 equipped aircraft over the years but probably the E1B5 in the Shrike the most. They are a great almost bullet proof and reliable engine. The main problem I've seen is starting with the wrong technique.
For a cold start crack the throttle, electric fuel pump on, mixture to full rich for about 6 seconds then idle cut off. Crank the engine and mixture to rich when she fires.
For a hot start if not shut down for more than 10 minutes. Crack the throttle, electric fuel pump on, mixture at idle cut off and crank the engine with the mixture to rich as she fires. If more than 10 minutes since shut down use this same procedure but just give the mixture the quickest up the full rich then idle cut off before you crank it.
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Old 5th Oct 2022, 23:14
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No personal experience but have read of the prop driving gearbox over the years, could someone please spell out the problem it causes, in all my reading never seen it mentioned. Many thanks in advance.
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Old 6th Oct 2022, 00:52
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Like many things in GA it was a passing comment from a older pilot and never really explained very well . The geared prop on a GTSIO -520 Titan was designed well when the engine was powering the prop but not so good the other way ? Easiest way to explain other way I guess is dressing the prop or testing for compression and you spin the prop causing the gearbox to work in opposite direction . In flight on a very rare occasion with very low power settings at high speed and you push the nose down I guess you could go past fine and like a fixed pitch prop it could drive the engine causing whiplash through that gear assembly ? This is my opinion only , could be wrong and I may have wasted my time being careful ? Happy to be corrected .
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Old 6th Oct 2022, 02:31
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Back in the ninety’s i turned up at a bush strip in a, new to me, small aerobatic radial engined aircraft. I went full fine on short final due to finger trouble. After landing a couple of young chaps wandered over from their large green Caribou for a chat and mentioned in passing that I shouldn’t have the prop driving the engine. I guess with the large engines in the Caribou it were an issue.




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Old 6th Oct 2022, 03:37
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shouldn’t have the prop driving the engine. I guess with the large engines in the Caribou it were an issue
The problem with a radial is that if the prop is doing the driving the loads on the master rod bearing are reversed, the oil feed is on the under power applied side, hence in the prop driving situation the side of the bearing taking the load is deprived of lubrication.

Going to full fine on short final shouldn't be an issue, flying the T-28 with the R-1820 the procedure was roll into the break with 45į of bank, throttle 15", speedbrake out, gear out 140kn, prop 2400RPM at 120 kn, at the abeam power 18 - 20" and prop full forward.
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Old 6th Oct 2022, 04:53
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Here's a good writeup from John Deakin about it, from near-on 20 years ago in the early days of Avweb!
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