Cary wrote:When I was instructing out of Laramie (elev. 7277'), most of it was in 172s of various vintage, including 145hp Continentals, and 150hp and 160hp Lycomings. Our "instrument trainer" was a 182, and we had 2 other 182s that we did some instructing in, but mostly that was for people transitioning to the larger, more powerful airplanes. So I spent a lot of time in 172s at high DAs.

Cary

Thanks for the stories. Those help me get a rough idea what to expect. Thanks for typing them out, that was quite the wall of text! (I hate typing, despite being a computer tech)

Its funny to hear stories of pilots who don't know about leaning or engine performance under various conditions.

I guess I take my knowledge for granted sometimes. Growing up on a farm you learn about engines, and how the environment effects them. I also have a VERY strong love of science and physics. I like studying how air moves, whether it be massive air currents around fronts or little vortexes coming off micro VGs. Shoot, the other day I sat and watched hawks fly. Its neat to watch them manipulate their wings and tail to maneuver.

I look forward to training in the mountains. Its a lot more interesting. Kansas is... well... uh.. uninteresting vertically. Well, I guess we do have thunderstorms! Those are kinda fun to watch pop up, as you quickly try to find somewhere to land before they eat you.
One of my favorite memories is on the leg back on my first x-country. We watched a massive storm roll in from out west. It was a long ways off, of course, but when they are state-wide and 60,000 ft tall they get pretty easy to see.

I learned in a C-150. One day it was getting fairly warm and humid and we found the climb rate to be lacking. The cows at the end of the runway had to duck abit. Needless to say, DA was the lesson of the day.

I know what you mean on the STOL kit. People tend to expect a bit much from the money they spend. As I mentioned before, I see them as extra cushion, NOT an excuse to push limits. I do like the way they make it fly, though.

Rocks around my flight path don't bother me, as long as I get the proper instruction.

P.S. Did you get in on this late winter storm, like we are?

ShadowAviator wrote:

Cary wrote:When I was instructing out of Laramie (elev. 7277'), most of it was in 172s of various vintage, including 145hp Continentals, and 150hp and 160hp Lycomings. Our "instrument trainer" was a 182, and we had 2 other 182s that we did some instructing in, but mostly that was for people transitioning to the larger, more powerful airplanes. So I spent a lot of time in 172s at high DAs.

Cary

<snip>
P.S. Did you get in on this late winter storm, like we are?

Oh yeah, it was really vicious. I think we got maybe 1 1/2" of snow at most. It was wet and heavy, though, so I went out and knocked it off the trees and bushes, and today on the way to church I saw a number of branches down, so I was glad I did that. Otherwise, it was pretty much a non-event here. I guess Denver got more, but still not exactly a Spring mega-storm. Fort Collins tends to have pretty gentle weather most of the time, like we're the hole in the weather doughnut.

Cary

Had another question pop into my head. I don't think it needs a new thread.

Anyway, I don't suppose theres a list of colorado mountain passes or routes that would be used by pilots?

I found a few on the Colorado Pilots website, but I am sure it didn't cover them all. I trying to familiarize myself with the various routes. For example, I was trying to find a route into Glenwood Springs, but there isn't much info on the best way to get there.

Wa180 wrote:Add a Powerflow exhaust if you plan to keep it. I added PF to mine, incidentally a 69K also, and it really helped climb rate, especially lightly loaded. I rarely fly by myself, my hangar manager often says, "at some point you gotta scare someone else...", but often 2 with half fuel.

Like many, I spent a lot of time in stock 172s training. A few years later, I flew a buddy's 172 with the H2AD engine both before and after he put the Powerflow exhaust on. Max RPM and fuel flow were higher and there was a major difference in climb performance. My mechanic also noted the same when he put the Powerflow on his Cherokee. I'd take a very serious look at this if I was flying a 172.



CAVU

Shadow Aviator,

The answer to your question about routes would depend on where you are coming from. Use of river valley and drainage routes are safest for low powered airplanes. We need to store energy reserves in airspeed or altitude trading one for the other as best serves our needs. Coolness decreases DA but wind, which generally accompanies heat, can be used for ridge lift near ridges downwind of the valley.

A common problem is attempting to maintain altitude in a downdraft. This is very energy inefficient. If we nose down a bit and trade altitude for airspeed, we get through down air quicker and can then trade that extra airspeed for altitude by flying slow in the next updraft.

Going up downwind ridges, maneuver constantly so that a turn back down drainage can be made. Allow the nose to go down normally (don't pull back ) in turns to maintain 1g and avoid load factor.

ShadowAviator wrote:Had another question pop into my head. I don't think it needs a new thread.

Anyway, I don't suppose theres a list of colorado mountain passes or routes that would be used by pilots?

I found a few on the Colorado Pilots website, but I am sure it didn't cover them all. I trying to familiarize myself with the various routes. For example, I was trying to find a route into Glenwood Springs, but there isn't much info on the best way to get there.

Like Contact said, depends on where you are at. That said, on my yearly Hadj to Idaho from Texas i cross just north of Denver. Basically draw a line from Fort Morgan to Afton Wyoming. Not to be attempted in the afternoon during the warm months. Blast off at dawn. The other way I've crossed the Rockies is way south in New Mexico, which probably wouldn't help.

To add to what others have said...get your flying done early. The 170/172 has a long track record as a mountain flying capable machine. The limitation is rarely the airplane, it's the connection between the yoke and the seat.

59SC.

ShadowAviator wrote:Had another question pop into my head. I don't think it needs a new thread.

Anyway, I don't suppose theres a list of colorado mountain passes or routes that would be used by pilots?

I found a few on the Colorado Pilots website, but I am sure it didn't cover them all. I trying to familiarize myself with the various routes. For example, I was trying to find a route into Glenwood Springs, but there isn't much info on the best way to get there.

There are a couple of publications which you'll find handy. The Colorado Airport Directory, which is downloadable at https://www.codot.gov/programs/aeronaut ... COArptDir; and the 2014-2015 Colorado Aeronautical Chart, which is downloadable at file:///C:/Documents%20and%20Settings/Owner/My%20Documents/Downloads/CO_2014CHART_web%20(3).pdf. The 2016-2017 Aeronautical Chart and a paper version of the Airport Directory can be ordered from the Colorado Division of Aeronautics, https://www.codot.gov/programs/aeronautics. That website has a whole lot of information that is helpful to pilots flying in Colorado.

Colorado has 13 state operated AWOS stations on passes, not necessarily co-located with airports, which are really nice. Here is information about them: https://www.codot.gov/programs/aeronautics/co_awos

A caution, though. The suggested routes on the chart aren't necessarily the best routes, and you still have to use some common sense and follow the basic rules of mountain flying, such as:
>Get your altitude for crossing any pass well before you get to the pass; circle climb if necessary.
>Don't ever try to outclimb the terrain.
>Don't play games with wind; my personal limit is 20 knots across the passes.
>Always have an out.
>When taking off, use the 50/70 rule, i.e., by 50% of the length of the airstrip, have 70% of your take off airspeed; if the airspeed isn't achieved at the halfway mark, abort. It's a good rule, but it only means you'll leave the ground before you get to the end, not that you can outclimb terrain after the end or that you can climb out of ground effect, so pay attention to what is beyond the end of the runway.
>Use normal landing and take-off airspeeds; the high DAs in the mountains mean that your groundspeed will be much higher, so don't let that fool you.
>At high DAs, don't raise the nose as high as you normally do, so that you can achieve the necessary climb speed; staying in low ground effect (a couple of feet above the airstrip) to accelerate above Vx is a good idea.
>Vx will be higher than book at high DAs.
>Pay attention to the direction of any wind and the resulting updrafts and downdrafts. Visualize it like water in a stream, which goes up and down over rocks and continues going up and down for some distance downstream.
Unless there's a strong wind blowing across a canyon, in which case you'll want to fly so that that wind gives you lift, fly to the right in canyons, anticipating oncoming traffic will also fly to their right. Your airplane is only 36' wide, so there's plenty of room to move away from the center of all but the very narrowest canyons.
>Turn your landing lights on.
>Monitor 122.9 and announce your positions on 122.9, which is the CTAF for the backcountry, until you're closer to any airport with a published CTAF.

Gosh, there are a lot more common practices and "rules", but that's the limit of my gray matter for the moment. Buy Sparky Imeson's Mountain Flying Bible--it has a lot of really good info in it. He wasn't a great writer, but he was a great mountain pilot, and there are a lot of gems in his book.

Cary

Thanks for the info! Those pictures really lit the fire under my seat.

However, on the mountain flying course, it looks like I could do the ground school but not the optional x-country. They say the plane should have at least 160 HP; mine has 150 HP. Would I just need to ask to get an actual answer? The ground school would be great, but the actual x-country would be really nice.

Edit:

Thanks Cary.

This is why I love asking questions here, there's just so much info!

I will dig through the links. While I may not do much for a while, I plan to do trips on my simulator on those rainy days. It is far from the real thing, but definitely helps with learning procedures.

Shadow

My minor difference with Cary is that I use Vy or Vy+ instead of Vx.
As you climb, Vx rises and Vy decreases until they are the same
at absolute altitude. Actually I try to accelerate as long as possible.

IF. your engine even coughs at Vx close to the ground,
THEN, you run a higher risk that you will hit the ground.

Don't know if it is OK to add this link- but I mostly agree with it.

https://www.advancedpilot.com/articles. ... cleid=1842

Best to all

Chris C

wannabe wrote:Shadow

My minor difference with Cary is that I use Vy or Vy+ instead of Vx.
As you climb, Vx rises and Vy decreases until they are the same
at absolute altitude. Actually I try to accelerate as long as possible.

IF. your engine even coughs at Vx close to the ground,
THEN, you run a higher risk that you will hit the ground.

Don't know if it is OK to add this link- but I mostly agree with it.

https://www.advancedpilot.com/articles. ... cleid=1842

Best to all

Chris C

I agree with you, Chris--that's why I said "staying in low ground effect (a couple of feet above the airstrip) to accelerate above Vx is a good idea." I should have been clearer. In my airplane, I try to get up to between 90-95 mph on the IAS before climbing, assuming terrain and obstacles allow.

Cary

I agree with Wannabe on the uselessness of V speeds or use of an airspeed indicator for contact flying.

When we turn a low powered airplane at high density altitude, God says, "You can pay me altitude now (let the nose go down normally) or pay me later (in the fall after mush or stall.") Banking will cost us airspeed or altitude. We must choose. Good energy management chooses wisely. No instrument will choose for us.

contactflying wrote:I agree with Wannabe on the uselessness of V speeds or use of an airspeed indicator for contact flying.

When we turn a low powered airplane at high density altitude, God says, "You can pay me altitude now (let the nose go down normally) or pay me later (in the fall after mush or stall.") Banking will cost us airspeed or altitude. We must choose. Good energy management chooses wisely. No instrument will choose for us.

Sometimes there can be alot of interest due if you delay that payment.

First time I flew to Aspen was in a turbo 210. As I crossed the pass west of Leadville at 12,500 I was certain no airplane with less power could make it. Then I parked next to a J3 Cub. Man did I ever feel out of my element as I was a flatlander. When I left I did the same in reverse. As I passed south of Leadville I said "self, let's do a touch and go at the highest paved airport in the US!" As I rotated nearing the end of the 6400' long runway I said "self, you're the biggest dumbass in aviation right now!"

GuppyWN ,

Yes, but the J-3 may have had to wait till the sun got high and the wind came up enough to produce enough wind for ridge lift.

Contact

GuppyWN wrote:First time I flew to Aspen was in a turbo 210. As I crossed the pass west of Leadville at 12,500 I was certain no airplane with less power could make it. Then I parked next to a J3 Cub. Man did I ever feel out of my element as I was a flatlander. When I left I did the same in reverse. As I passed south of Leadville I said "self, let's do a touch and go at the highest paved airport in the US!" As I rotated nearing the end of the 6400' long runway I said "self, you're the biggest dumbass in aviation right now!"

The day I was at Leadville, the DA was 12,100' when I left. I was running light--2/3 fuel, only ol' Dog Molly in the backseat, plus my usual survival stuff in the trunk. That was about 7 1/2 years ago, so she wasn't an old dog then.




Climb rate was a good 200 fpm! Here we're on downwind, departing the pattern, with the runway visible and the town of Leadville in the background.




Flying at really high DAs is a different thing from talking about them for all of 5 minutes, which is the usual training most flatlanders receive during their private pilot training.

Cary

I don't have anything to add to using a 145 hp C172 in your area (go for it), but I wanted to add one point to consider for high DA flying

Everyone always tells you what to expect on takeoff, but I almost never hear cautions regarding to DA affects on landings.

When I was learning mountain flying I recall lining up on a runway that required actual short field technique where you had to come through a slot in the trees to your touchdown spot.

I was holding 60 mph which is nice and slow but when we went by those trees it sure felt like we were smoking down final. The reason is because it was considerably faster than 60, even with a headwind.

The same thing that causes the airspeed indicator to show low on takeoff (actual ground speed higher than indicated) causes your speed on final to be longer, and if you're not good at landing where you intend to it could cause you to use quite a bit more runway getting stopped than you're used to.

The landing distance is still calculated using the tables of course, but be prepared for a WTF moment if there are obstacles on final and the appear to be moving more quickly than normal.

Good point aftCG. While not using the airspeed indicator for the apparent brisk walk rate of closure approach, the apparent brisk walk will cause the airplane to mush sooner at that lesser pressure of airspeed you are talking about. We may need an apparent slow trot instead of brisk walk. We go by the relative buoyancy and relative wind. We have to go a little faster to get the same sound with the molecules farther apart.

Mainly expect to see a bit faster apparent rate of closure. If the sink rate is too fast, add more power.

aftCG wrote:I don't have anything to add to using a 145 hp C172 in your area (go for it), but I wanted to add one point to consider for high DA flying

Everyone always tells you what to expect on takeoff, but I almost never hear cautions regarding to DA affects on landings.

When I was learning mountain flying I recall lining up on a runway that required actual short field technique where you had to come through a slot in the trees to your touchdown spot.

I was holding 60 mph which is nice and slow but when we went by those trees it sure felt like we were smoking down final. The reason is because it was considerably faster than 60, even with a headwind.

The same thing that causes the airspeed indicator to show low on takeoff (actual ground speed higher than indicated) causes your speed on final to be longer, and if you're not good at landing where you intend to it could cause you to use quite a bit more runway getting stopped than you're used to.

The landing distance is still calculated using the tables of course, but be prepared for a WTF moment if there are obstacles on final and the appear to be moving more quickly than normal.

Excellent point. When I first started looking at the videos of folks landing in "high country", I kept thinking "Wow, those guys are cooking on final approach... Wonder why they are flying so fast? Wouldn't they be better off flying a slower approach?"

It wasn't until I started really thinking about high DA operations that it occurred to me that at the same "indicated" airspeeds, the groundspeed would be significantly faster... Then I felt like a shmuck for mentally critiquing those excellent pilots who have 100X the skill and experience I have... So much to learn!

Good point. Watch my (poorly videographed) video of landing at Marble, CO, here: https://www.youtube.com/watch?v=iGAN6pDYt_4 Starting at about the 5 minute mark, you can get an idea of the "high speed" effect caused by high density altitude. I'm pretty careful about final approach speeds, so I don't think I was going faster than 60 knots (70 mph)--though that was long enough ago that I can't swear to it. But you can hear the stall warner go off just before touchdown.

Cary