201er

No, I think my MP and ram air are just fine and the POH is in error. 22.5" sounds about right for 7,500MSL whereas my POH suggests 23.6" for 8,000!!! The MP gauge reads normal pressure when the engine is off on the ground and the ram air gives me the expected .25inHG boost in MP. But to be over 1" off on the book makes a pretty big difference. So what I'd like to know is if everything else is thrown off or just the MP values. Is the plane only producing 70% power at 8000ft as the result of actual MP being 22" rather than 23.6" or do you really get 75% at 8000ft but their MP listings are off? Anyone have additional data to verify this?

I've been making some recent efforts to look for ways to optimize max speed in my 201. Still can't get close to book numbers. Then while talking to someone about a speed test flight I did today, he caught on to something. I pointed out that today was a very close to standard sort of day and yet the max MP I was getting came shy of POH power table values. I explained how I was getting 22" MP at 7,500 while the book was giving figures based on 23.6". I originally figured it was just the conditions or I wasn't developing max available MP (even with ram air open). Well based on the 1" per 1000ft rule of thumb and more specifically looking up a table, I discovered that the POH inflate available MP substantially for the max power settings and that has a bit to do with why I'm not attaining book value speeds. So while standard pressure at 8,000ft should be 22.225 inHG, the Mooney POH gives a 75% power setting based on 23.6" at the same standard temperature of -1C. Where the heck are they getting this number from? How is this supposed to be useful to me when it is inflated over 1.3"? I checked for other altitudes and the error was not constant so I don't think it is expected boost as the result of ram air. I also looked at power tables for other airplanes and they tend to have a more standard MP value relative to altitude. Anyone know what this is about? Is the error strictly limited to the MP value or are the %power and speeds derived based on that exact MP? Does this mean that 75% is actually impossible above 6,500ft under standard conditions?

For my '78 201 the gear extension speed is 134kias and 109kias for retraction. What I wonder is how critical these numbers are? Has anyone exceeded these speeds and gotten away with it? Or has anyone exceeded them inadvertantly which resulted in gear damage? Personally I try to be careful and make sure I've slowed down sufficiently before extending gear. As for retracting, I have a hard time remembering that it's a lower speed for retraction but I'm in the habit of retracting the gear not long after takeoff so that helps me avoid that problem. But now during my instrument training, I'm dealing with a tougher workload and am afraid of not slowing down sufficiently to retract the gear on the missed approach.

Why not just fly off what you can beforehand and arrive with just minimal fuel and dump it? You may need a refresher on running tanks dry though =)

So how do the turbo guys fly their machines in the flight levels? Is it a different prop or same one? Since the engine is getting complete aspiration, can you fly the same RPM settings as a non turbo at low altitudes? Or do you need to increase RPM at high altitude to compensate for thinning air?

Well since the "bite" is different relative to air density and thus altitude, can it be said that this has some kind of effect on the L/D of the prop? Does this put it into a more or less efficient operation than comparable RPM at sea level? Does this affect more than a few knots or purely theoretical?

Hmm... anyone wanna tell me about props? lol

Fascinating. Does age and wear/tear of an engine affect real world results to tests? Is chart #3 a demonstration of the danger of being oversquare?

Quote: jetdriven

Quote: jetdriven I was thinking about a MOO-share idea where M20J pilots over the country pledge their aircraft, and others in the program can rent the airplane for a nominal fee, such as 30$ plus gas. Open pilot warranty wil cover you. Could work also for M20C, E, F, and K as well. This allows owners in the network to fly in a variety of areas in the country without paying 500$ to checkout and then rent a skyhawk. Interested?

Thanks. That is definitely an important point to keep in mind. But once below 65% where is the goal to be mixture wise? You can put it anywhere, but is it ideal to be at peak or LOP? Can't it be argued that outside the red zone and with manageable CHTs, peak is the ideal compromise of power/gas efficiency? So is there any reason to be at 55% power and LOP anyway? At low power settings, are you definitely immune from any risks of improper leaning or poor gami spread?

Once the power setting is low enough that CHTs are acceptable regardless of peak or LOP (generally below 65%), is it ideal to fly at peak or LOP? Also when flying at peak, should you have the leanest cylinder at peak at the rest ROP or the richest cylinder at peak and the rest LOP? Does it even matter? Is there something wrong with having a couple cylinders ROP while the others are LOP when aiming for peak?

Question, when you share halos with random passengers, do you change the ear pieces? Are they cheap/disposable? Or do you have to wash them out after someone else uses them?

Since the air is thinner at higher altitude, does prop efficiency and performance change? For exmaple I've always been taught to avoid cruise at highest RPM (above 2500). But at higher altitude you may have to choose between low power or highest RPM. Is it "less bad" to fly 2600/2700RPM at 8000+ feet than it is down at 2000' cause the air is thinner? Or is it just that you don't have much choice?

Besides price what's the disadvantage? I had guys telling me that the fine wire could be the same or worse in some cases. Also is it really better to have fine wire rather than to replace normal ones more frequently?

My Mooney came to me with fine wire but other guys and mechanics have beens suggesting not to go with them in the future. I don't know about this kind of stuff at all so I was hoping you guys could let me know the differences, merits, and values of fine wire vs not spark plugs and how that works out in your Mooney.

Maybe it's cause I've flown planes with just one fuel tank or none at all that it doesn't seem like such a big deal to concentrate it all in one place for the final amount of fuel. Actually, it's kinda funny that by the time I'm down to a single tank in my Mooney, it is holding more gas than the entire single tank in the Piper Cub I trained in could hold.

Quote: N4352H The logic of all this is flawed beyond reason. You guys are suggesting that if you run one tank dry, you'll know the exact quantity (or even close) in the other or that you'll be less prone to a tank switching error at a lower altitude.

Quote: N4352H Who is going to fly a Mooney 201 with 4 passengers and 15 or fewer gallons of fuel? Have a safe flight!!

Quote: N4352H No. Having it all in one tank would be less preferable.

Does no one here fly with 4 people onboard? Perhaps some baggage? That kinda stuff can easily restrict you to be starting out with less than 50 gallons. 3 hour flight, no biggie. 30-35 gallons of fuel used. That leaves 15-20 gallons. It's not bad until you realize it's split between two tanks and who is going to rely on the last 5 gallons in a tank down in the pattern?

I really don't understand how some people think it is safer to have a little in each tank and risk having to do a tank swap low to the ground (say on a go around) than to have more in one tank and nothing in the other? I would much rather run a tank dry in cruise and leave 2 hours in the remaining tank than to have some arbitrary amount of roughly half in each. Think about it, if you have 1 hour in each side... you run one of those sides down to what 30 minutes? 20 minutes? Now you get nervous about going dry, perhaps you're in a go around so you swap to the 1 hour tank. Before you know it you have 20 in one tank and 20 in the other. That's not a situation I want to be in. Now I'd like to ask the guys who run a tank dry in flight. How high and/or in what condition of flight do you want to be in when you do it? Do you have to be over an airport? Do you have to be over a certain height AGL that you will feel comfortable doing it? Or would you run a tank dry during a low cruise at 2000ft?

How do you get it out from behind all the tubing and stuff back there without disconnecting everything? Any suggestions?

Quote: fantom Yes, and be concise. Listen up, look outside rather than at your GPS, don't ask "any other traffic, please advise". If there's a dumber request, I haven't heard it.

If you can get him to spin it too, I think there is a certain someone on this forum that would pay him for you to do it