So that's what adjusting the timing...

EdFred

EdFred

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...and replacing the points at annual gets me.

In three years of owning the Comanche, I've pretty much been at 147-148ktas when running at 2300 and WOT/25" whichever is less while burning 13+/hour while in in the 3000' - 8000' range.

I had a St Jude's charity tournament in Bloomington, IL this past weekend, and was interested to see what difference it would make since I hadn't been able to get out and really run it through its paces.

5,500', 23.5"/2300 12.7gph - 154-155ktas.

Who says annuals are a bad thing?

Should save me $50 on my Wings trip.
 
Nice!
Points... So quaint...

I'm hoping to save $1.75 on oil, now that we've "tightened" some things up a bit.
 
EdFred said:
...and replacing the points at annual gets me.

In three years of owning the Comanche, I've pretty much been at 147-148ktas when running at 2300 and WOT/25" whichever is less while burning 13+/hour while in in the 3000' - 8000' range.

I had a St Jude's charity tournament in Bloomington, IL this past weekend, and was interested to see what difference it would make since I hadn't been able to get out and really run it through its paces.

5,500', 23.5"/2300 12.7gph - 154-155ktas.

Who says annuals are a bad thing?

Should save me $50 on my Wings trip.
Click to expand...

So was the adjustment, and parts $50 too? Pay for itself in one trip, or two? :)

Doesn't really matter... done right is done right, after all... just curious.
 
I am having difficulty believing a tune-up could gain 8kts in speed!
 
Let'sgoflying! said:
I am having difficulty believing a tune-up could gain 8kts in speed!
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It's amazing how people don't notice a gradual decrease in performance. It's been so long since our cars ran points and leaded fuel that we have forgotten that we needed 'tune ups' to keep the dwell and therefore the timing on mark.
 
Henning said:
It's amazing how people don't notice a gradual decrease in performance. It's been so long since our cars ran points and leaded fuel that we have forgotten that we needed 'tune ups' to keep the dwell and therefore the timing on mark.
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In a magneto, the wear of the points and/or their cam not only changes the "dwell" but it shifts the E-gap so that the spark becomes weaker and the timing will either advance (worn points) or retard (worn cam). All of it affects engine power and efficiency.

Dan
 
This sounds fairly amenable to some research, if anyone can be talked into it!
 
Let'sgoflying! said:
This sounds fairly amenable to some research, if anyone can be talked into it!
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LOL, tons of research has been done over many decades...:rofl::rofl::rofl: Welcome to the history of drag racing where 10s of thousands are spent for tens of thousandths.:yesnod:
 
I completed an annual on a 170/0-300
the previous A&P had told the owner the right mag was shot, he had a new one on hand, but when I pulled the plugs 9 of the 12 were totally worn out, after I changed the 9 plugs and cleaned the other 3, the 0-300 ran a 50/50 mag drop.

I opened the 664 slick and there was nothing wrong with it at all, nearly 1300 hours run time.
It's not always the mag, do the simple stuff first, fix it at the lowest cost to the customer.

All I did to the 664 was check condition of the rotor, distributor block, add a drop of oil to the felt wiper and closed it up.
 
Let'sgoflying! said:
This sounds fairly amenable to some research, if anyone can be talked into it!
Click to expand...

It's been researched significantly over time. This was one of the negatives of points and magnetos - the fact that timing does drift, as does the quality of spark. With the advent of distributor electronic ignition, distributor caps and rotors need to be changed now and then (as well as wires), but that's about it.

Modern distributorless ignition (such as the sort that we've seen in production for about 20 years now on cars) is nice because it either works or it doesn't. Although in an airplane that may be somewhat questionable for its desirability, but I think overall it would be an improvement.

I would like to see a PMA'd replacement for a magneto that incorporates modern electronic ignition. The real problem is figuring out how to package it into something that will fit properly. It would likely need to get bolted elsewhere and then run longer wires.
 
Ted DuPuis said:
I would like to see a PMA'd replacement for a magneto that incorporates modern electronic ignition. The real problem is figuring out how to package it into something that will fit properly. It would likely need to get bolted elsewhere and then run longer wires.
Click to expand...
You mean something like this?
 
Ted DuPuis said:
Modern distributorless ignition (such as the sort that we've seen in production for about 20 years now on cars) is nice because it either works or it doesn't. Although in an airplane that may be somewhat questionable for its desirability...
Click to expand...
That's why there are two of them on my engine...
 
Capt. Geoffrey Thorpe said:
That's why there are two of them on my engine...
Click to expand...

Thats one option (and a good one too) another might be to get timming information from elsewhere on the engine and leave the mags (or a mag) in place, grounded to be used in the event of a primary ignition failure. Sort of like a Cessna 195
 
I've done a couple more flights, and everything seems to be consistently better than prior to the annual. Fuel flow meter was within a gallon (said I burned a shade more) on a ~46 gallon burn of what the pump said I put in the tank, but I can probably squeeze an extra gallon in by coming up the filler necks a bit more as well.

Flying back from my multi I was at 9500, burning 10.7gph and getting 150ktas at approximately ISA.

This weekend's flight was 7500 one direction and 8500 the other. Temps above standard, pressure above standard, still getting 155ktas both directions according to the 430's E6B. Even had 159ktas at one point, but I might have been getting some lift, and picked up speed to maintain altitude, but still had sub 13gph burns.

To quote a lawyer on here, it feels like I'm cheatin'.
 
That's great to hear Ed. There is nothing like "free" performance, although we all know it ain't "free".
 
I know. Looks like my flight to Wings is gonna be under 3 hours. :eek: :D
 
EdFred said:
I know. Looks like my flight to Wings is gonna be under 3 hours. :eek: :D
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Yeah, that's pretty good. 233 Knots/hour ground speed if you go direct over three Great Lakes. :D
 
Anthony said:
Yeah, that's pretty good. 233 Knots/hour ground speed if you go direct over three Great Lakes. :D
Click to expand...

I'm based at 9D9 not 6Y9. 484nm 9D9 --> DXO --> HAR --> LRP --> BUNTS --> LOM

Looks like I'll have 20kt tailwind. 2hr 46m. Of course I might get rerouted early.
 
Your timing must have been >/=5 degrees retarded before. What else did they do?
 
My mistake! I thought you were based at 6Y9.
 
Let'sgoflying! said:
Your timing must have been >/=5 degrees retarded before. What else did they do?
Click to expand...

I am pretty sure he did mention 5 degrees before he did it. Then I asked him after it was done, and he didn't recall exactly how much it was off. Other than replacing the points, nothing else was done on the engine or air frame which would increase performance or decrease drag. Didn't change the plugs, didn't re-rig, just the timing on the mag.
 
EdFred said:
I'm based at 9D9 not 6Y9. 484nm 9D9 --> DXO --> HAR --> LRP --> BUNTS --> LOM

Looks like I'll have 20kt tailwind. 2hr 46m. Of course I might get rerouted early.
Click to expand...

~195Kts groundspeed. I didn't know Commanche's can do 175KTAS
 
Anthony said:
233 Knots/hour
Click to expand...

The Department of Redundancy Department has a number they would like you to call. Advise when ready to copy.....

-Skip :wink2:
 
Tom-D said:
I completed an annual on a 170/0-300
the previous A&P had told the owner the right mag was shot, he had a new one on hand, but when I pulled the plugs 9 of the 12 were totally worn out, after I changed the 9 plugs and cleaned the other 3, the 0-300 ran a 50/50 mag drop.

I opened the 664 slick and there was nothing wrong with it at all, nearly 1300 hours run time.
It's not always the mag, do the simple stuff first, fix it at the lowest cost to the customer.

All I did to the 664 was check condition of the rotor, distributor block, add a drop of oil to the felt wiper and closed it up.
Click to expand...

was that 1300 hours with out a mag overhaul. My mechanic told me 500 hour mag overhauls.
 
Bob Bement said:
was that 1300 hours with out a mag overhaul. My mechanic told me 500 hour mag overhauls.
Click to expand...

Have him show you where that is required? Slick has a service bulletin they would like you to think is to be done every 500 hours.

It was the old style 664, so I would think it was 1300 TT.

I saw no entries that said it had been overhauled.
 
Didn't know you were flying the Galileo.
 
Anthony said:
Yeah, that's pretty good. 233 Knots/hour ground speed if you go direct over three Great Lakes. :D
Click to expand...

"Knots" already has the "/hour" built in, it is a speed standard of 'nautical miles per hour' in one word.
 
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