That odd shaped panel cutout with the carb temp gauge in it posted above is the original location of the magnetic compass on 1953 trough 1956 170B's.

Tim

bat443 wrote:That odd shaped panel cutout with the carb temp gauge in it posted above is the original location of the magnetic compass on 1953 trough 1956 170B's.

Tim

Yep. I already have a compass up on the windshield strap and after 25 years of it living up there, it ain't going anywhere.

I'm quite happy with the Richter carb temp gauge that has been in my 170B since 1969.

I will say I’m surprised nobody mentioned the dangers of running carb heat on the ground. I will verify my carb heat works in the runup at a paved airport but I’ll never do that on dirt, just too much risk of sucking crap into your motor.

hamer wrote:I will say I’m surprised nobody mentioned the dangers of running carb heat on the ground. I will verify my carb heat works in the runup at a paved airport but I’ll never do that on dirt, just too much risk of sucking crap into your motor.

IMO a departure with carb ice limiting your engine performance is more dangerous than a little bit of unfiltered air.

Aryana wrote:There's usually only a small penalty to having carb heat on when you don't actually have ice (less engine power, unfiltered air), but the consequences can be huge if you don't have the carb heat on when you should.

All things equal, an O-300 usually ices up easier than an O-470. Use carb heat sparingly in the O-300 in the right conditions and you will get tested before you ever have a chance to study!

The O-300 is capable of icing up while idling on the ramp. I always leave my heat on after my run up and turn it off just before take off.

But if you instead err on the side of caution and use carb heat regularly, you won't ever experience the terror of listening to one of these engines choke on water and quit running.

Aryana, I was sure with your wealth of 170 experience you knew what that space was originally used for but thought it might be of interest to others not so familiar.

Tim

Sometimes, I wish we were drinking beers around a campfire together instead of posting messages. I suck at the internet. [emoji2359]

Aryana wrote:Sometimes, I wish we were drinking beers around a campfire together instead of posting messages. I suck at the internet. [emoji2359]

Amen to that.

A1Skinner wrote:

Aryana wrote:Sometimes, I wish we were drinking beers around a campfire together instead of posting messages. I suck at the internet. [emoji2359]

Amen to that.

Aye Aye to that

I too have problems communicating through the internet. I know at times I seem to be talking down to the knowledgeable reader but that is never my intent but rather to explain things well enough that five years from now a reader who knows little about or may have never even seen what we are talking about will hopefully be able to learn and understand the subject discussed. So if at times I offend someone with the tone of an explanation please accept by sincere apology. I do much better face to face. Oh, and text, don't even go there.

Tim

Yeah, when go back and read my posts I shake my head in disgust when I sound like a prick...it's a total disconnect from what I think I sound like when I'm typing it.

Zane has a thread from a while back about posting with care and thought. Maybe I should dig it up as a reminder.

I still like chatting with you guys even though I come across as an asshole on the internet [emoji2359]

I humbly apologize in advance to you all. I'm much more fun in person. I'm not a professional writer/communicator by any means.

Heck, English isn't even my first language! That's my excuse and I'm sticking with it =)

Maybe we should implement a new rule, drink beers while you post. Ha

It wasn't until a read some of my own "finest work" that I realized how challanged I was in basic written communication skills.

When I started reading this thread I thought it was going to be about airframe icing, which I thought was timely since I had my first encounter of the season with a couple days ago. Good reminder to be vigilant about carb icing though.

Ice is ice; if we can all learn from your recent experience please share, either here or a new post.

Thank you in advance

Thread revival... thanks to Bigrenna's lurker post.

I have about 2500 hours of single engine piston time, about half of that behind the O-470U in my 180. That's enough time to have a healthy dose of complacency, which always lurks in the background despite my efforts to eradicate it.

I flew my 180 to Alaska and back this year. 60 hour round trip over about five weeks. My wife and son rode partway up with me, and good buddy rode partway back. That's a whole other story, no better than any of the similar ones told here before. And, it's just another great adventure I've had in my 180.

Three years ago I put an EDM-730 in my 180. Who knew a little box and some wires could be so informative about the innards of my 2200 SMOH engine. Not me, of course... but I'm a convert and I regularly download the engine data and upload it to Savvy Aviation's website for review. When I got to Anchorage I saw this:



The odd left-right EGT split was unlike anything I'd seen before. The Savvy guys suspected an exhaust leak. I found a shop, they found a broken clamp, and a test flight on a clear August day seemed to indicate normal operation. Problem solved, or so I thought.

Fast forward a couple weeks. Now I'm headed home, hoping to fly the Trench south. Weather started out OK, but deteriorated as we got further into it. It looked like this:



I know, I can see a mile and a half left and a mile and a half right... that's three miles, correct? Clearly raining, temperature in the 40s, humidity pretty close to 100%. Not good enough for me to be comfortable. Also ideal carb ice conditions, not that I recognized that just yet.

While I was wrestling with this weather decision, I noticed the EGT split on the EDM-730 again. So now I have two monkeys on my back. The weather is crap and getting worse, and my exhaust leak is back. I'm at about 1500 AGL a few dozen miles off the highway. Not the best place to be. I'm starting to look at the tundra below, wondering what it would be like to land on and how in the heck I'd get out of there if we did have to land.

I had a pilot buddy in the right seat, and we are going back and forth about the weather and the EGTs. After several minutes I look down and realize that the manifold pressure has backed off from about 21" to about 17". I look further down into the corner of the panel and the carb heat temp is in the yellow.

That is the wakeup call that I need. I pull on the carb heat. The engine sputters and then roars as the manifold pressure returns back to 21". I snap out of my frustration and we turn back to the highway and on to Ft Nelson. The EGTs go right back to where they should be, marching in tandem with no left-right split. Forget about an exhaust leak... I realize that carb ice had been the cause of my EGT split all along.

As we get pavement back under us and better weather around us, I start to realize just how complacent I had become with carb ice. I know the O-470 has a reputation for it, but I'd never seen it before in over 12 years of flying this aircraft, and that includes a fair amount of IMC and winter weather operations. My pilot buddy's totality of aviation experience is in turbines and fuel-injected pistons, so carb ice is as foreign to him as the inner workings of the sun. As I explain it to him, I curse my own stupidity for not recognizing it earlier on this flight, and for not recognizing it on the previous flight where I recorded the EGT split. Too much data, perhaps? Probably... I was focused on an EGT issue when I should have been paying more attention to the manifold pressure and carb temp all along.

Now, why did carb heat cause an EGT split in my engine? Haven't figured that one out yet... I'll let you know when I do!

The O-470 is a great engine, no doubt, but the induction logs are so long that the cylinders receive very different induction temps. I suspect that was the case in your example. Front cylinders are in cold air, and their induction tubes are furthest forward. I’m guessing the induction cross tube on your engine is not insulated? Cold air on that tube, right up front, will cause serious differences in cold.

Combine that with an induction that’s icing up, and your eggs may reflect it.

If your cross tube isnt insulated, go to Lowe’s Aircraft Supply, buy some split pipe insulation, and some zip ties. Pull the lower cowl, fit the pipe insulation, zip tie, and go fly.

MTV

mtv wrote: Pull the lower cowl, fit the pipe insulation, zip tie, and go fly.

I would just add that while your at lowes. Make sure to go over to the service counter and ask them for the Lowes pluming STC. Its usually behind the counter….

FWIW, the 470/520 has 3 sizes of crossover tubes. The smallest one helps the most with carb ice. This is especially important on the bigger pponk and O-520.

FWIW, the 470/520 has 3 sizes of crossover tubes. The smallest one helps the most with carb ice. This is especially important on the bigger pponk and O-520.

This is what Central Cylinder put on the 470U that they converted to Pponk for me. It is even smaller than the one that came on the 470U on the Cessna 180K and the smallest I've ever seen.

180Marty wrote:…the smallest I've ever seen.

Yup. Thats what you want

Those are good tips. I'm more of a Home Depot kind of guy. Do they also offer the STC?

Seriously... what makes the small crossover tube better? I would think that a larger diameter tube takes longer to get clogged... or is it a pressure/temperature thing that I probably learned in class and forgot right after the test?