Older aircraft with MPH vs Knots

Have MPH on the outer and knots on the inner. POH is in MPH with equivalent speeds in knots in parenthesis. My instrument instructor wanted me to learn my speeds in knots but that inner dial was too hard to read with my old eyes.

One side benefit I've noticed is whatever the airspeed indicator reads in MPH IAS is pretty close to the calculated TAS in knots.
 
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Not really a big deal, the v speeds are in mph in your POH, the ASI is in MPH, just need to convert for the flight planning.
 
Only one of our aircraft reads in MPH the other 14 use Knots. So all of our POHs use Knots since it works on all but one. It gets real interesting when a pre-solo student receives that plane for the first time. We usually end up trying to takeoff at 52 MPH instead of 52 Knots. :eek:
 
ARFlyer said:
So all of our POHs use Knots since it works on all but one.
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That some stupid stuff right there, especially if you're putting students in it.

I'm not going to look in the FAR right now but that might not turn out well if that plane gets ramped.
 
i have been flying an arrow in mph. no difference except for nav calculations. if you know how to read an airspeed indicator all the speeds are there and adjustments are not necessary. for all i care the units can be in inches/second and it wont make a diferrence if the pilot knows how to correctly read an asi.
 
BiffJ said:
Quit worrying about what the airspeed is measured in. Its makes no difference. Use the numbers for that particular airplane and the guage it has in it.
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This is the best suggestion. The number really means nothing in the long run. Just be familiar with what number you should be seeing at a given time in the aircraft you're flying.

At work I see everything measured in metric, at the airport and at home it is a mix. I have never really bothered to try and convert the numbers although after a while you end up being able to subconsciously do the conversions in your head.
 
James331 said:
That some stupid stuff right there, especially if you're putting students in it.

I'm not going to look in the FAR right now but that might not turn out well if that plane gets ramped.
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MY BAD- I forgot to include that it's a dual speed ASI. However, the students tend to fly the MPH arc since it stands out more.

The AFM for that plane is in MPH. However, our standardized POH is in Knots. They've been trying to switch the ASI for years. It just keeps getting throw to the back burner whenever something else comes up.

It's actually second on the list to get a new panel by Christmas. So the problem should be gone by the start of the year.
 
BiffJ said:
Quit worrying about what the airspeed is measured in. Its makes no difference. Use the numbers for that particular airplane and the guage it has in it. If it reads in kilometers, arshins or inches per day it makes no difference. If the book or the check pilot says use 291 1/2 on the guage for approach that is the number you use. I've been flying since the mid 80s in rentals, loaners and my own planes and never had a single issue with the nomenclature of the guages. Use the number for the plane and you'll be fine. Try to convert to a number convenient to you and you'll waste enough time to be dangerous to yourself and others. Quit converting and just fly. You'll be much happier for it.

Frank
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/thread.
 
My instructor trained me in a 172N (40° flaps and MPH) and a 172P (30° flaps and KTS). We are in a high desert environment.

I was trained to aim for 80mph or 70kts on base and down final, then on short final slow to 75mph/65kts for a normal landing (20° of flaps). If going to full flaps, a bit slower. I still do landings like this and from what I have read here, it is a bit fast. It works well in the 172P but the N tends to float some.

With full fuel (40gal), and 300lbs of people, what should my speed be according to Cary? :D

When switching, I tend to us kts for my rotate, Vx and Vy speeds regardless of which aircraft since the MPH ASI also has kts, but for landings I use the outer dial which is MPH or KTS depending on the aircraft. I wish everything was in kts.
 
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Why do you land with only 20 flaps?
 
James331 said:
Why do you land with only 20 flaps?
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'cause my home field has 10,000' runways and the airport I practice at most of the time has 9,000' runways and it makes for a smoother landing most of the time. About half the time I land with full flaps - just to vary things a bit. At other local airports with smaller runways I always use full flaps. I think the shortest runway around here is 4000' or so.

Sierraville (O79) is at 4984' elevation and has just 3200' of runway but one end of it is at the base of a mountain with 100' trees. I have never landed there but have done low approaches in the winter when it is partially covered in snow. it's a stupid place to have built a runway when the rest of the valley is completely flat and open.
 
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Gotcha, nice having that real estate. Only problem I've found with those places is they tend to be busier and have the terrorist police TSA wannabes, which gets annoying.
 
Reno is pretty busy but just 10miles north we are lucky to have Stead airport (site of the Reno Air Races). It's an abandoned Air Force base with huge excellent condition runways. It's a great GA field.

30 miles south of here is Minden which has a 7400' runway and a good restaurant on the field. SIlver Springs is another place I practice and that has 6000'. Now keep in mind most place here are near 5000' elevation and it is hot in the summer, but it is still weird for me to see sea-level runways of 3000' and not think, "wow, that's not very long". Only Reno really has the TSA goons.
 
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CTLSi said:
You should always be watching airspeed, not some color coded bar when turning base to final and final to landing.
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Bullhockey. The arcs are airspeed to and they are normalized to your BELOVED stall speed.
 
brian];1537179 said:
Too bad. The good news is I seem to have a lot of early 35 owners in the area that have been helping me. (This is my first year with the -35.)

Once I get the gear down, slowing down to 90 (base), and 80 (over the fence). But some of the 35 owners push it like a BE55 - and plant the gear on the pavement. Works, but it can't be good on the tires...

I'll try a few more things to slow down on downwind...

(Sorry about the thread hijack - but I have something new to try/learn ...)
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No worries. There's been some pretty useful stuff in the conversation. Besides... I'm learning the pattern for almost every thread on this forum. Someone posts something/anything, at least one poster questions its legality, a handful will post what amounts to "i've been doing this for a hundred years and I do it this way, you're stupid" and then there is the relevant conversation and sidebars (which are usually partially relevant too). Doesn't matter if it's about certification of airmen, soloing or your favorite snack food.

Talked with my CFI about the transition after my last landing in it. Long story short he said I have a tendency to come in a bit hot and that's much better than too slow while I adjust. The landing that brought up this question in the first place just made me jump a bit. I was on short final and noticed the slow down. Looked down and i had dropped to 60mph and starting to go slower. So I gave it a bit of power and came in perfect.

With my last CFI, when I was flying S model, I typically had power all the way out once I turned final or on short final. I'm finding that with my older airplane I probably need to keep some power in. There are some pretty huge differences but all in all, she's really starting to grow on me and once I get a bit more adjusted it's going to be great. So far I like her better than the S model.
 
brian];1537148 said:
Hey - I'm an imperfect person - all suggestions welcome :)

Might be interesting to meet up or talk offline (are you on BeechTalk?). I have no problem getting to the upper 90's on downwind, but any slower is kinda hard on that slick airplane. (Ok, I could pull the nose up.) No problem flying in the 80's - but I found it made my BPPP instructor very nervous. I didn't expect that one...
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Really? Scared at 80? That's sad, your plane at light weights can still fly near half that.
 
Henning said:
Really? Scared at 80? That's sad, your plane at light weights can still fly near half that.
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Not sure about 1/2 that - unless you are talking KTS ;)

The wing tends to let go at about 55MPH (give or take). To be honest, I'm still a little nervous doing stalls in the -35 - not quite the same as a DA20 or C172. But, I'm getting there - even hoping to start doing some accelerated stalls at some point :yikes:

I guess that is the key element here - get to know your airplane.
 
Ron Levy said:
You were probably flying it at the "recommended" 65-70 knots, which really is too bloody fast, especially solo. In such a case, 60 knots is a lot better choice -- maybe even a couple of knots less if you're solo with no baggage/cargo and less than half tanks.
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:D

And then you get into the older ramp queen and wonder why the stall warning keeps chirping at you coming down final; until you adjust your eyeballs and note the annotation says "MPH" on the gauge instead of "KNOTS"

BTDT
:)
 
brian];1537408 said:
Not sure about 1/2 that - unless you are talking KTS ;)

The wing tends to let go at about 55MPH (give or take). To be honest, I'm still a little nervous doing stalls in the -35 - not quite the same as a DA20 or C172. But, I'm getting there - even hoping to start doing some accelerated stalls at some point :yikes:

I guess that is the key element here - get to know your airplane.
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Go ahead and do some stalls at light weight and see where it stalls, then you can go into your IAS-CAS table and find that CAS and derive your 1.1, 1.2, 1.3 & 1.5 Vso speeds and find their IAS equivalents. Now you have your real pattern speeds for your typical one man landing weights.
 
flyingron said:
Bullhockey. The arcs are airspeed to and they are normalized to your BELOVED stall speed.
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Like I said, you should ALWLAYS be watching your IAS airspeed when changing your flaps, when in cruise, when dealing with Va, and especially when entering base and then to final.

When over the threshold you should have a number NAILED... If you fly the numbers you can transition easily between glass and steam. In the glass cockpit the arcs are barely noticeable.
 
oldShar said:
:D

And then you get into the older ramp queen and wonder why the stall warning keeps chirping at you coming down final; until you adjust your eyeballs and note the annotation says "MPH" on the gauge instead of "KNOTS"

BTDT
:)
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And thats the summary for the reason behind my original question. Side note, she's no longer a ramp queen. 7.5 hours flight time from Friday to Sunday
 
James331 said:
I'm not going to look in the FAR right now but that might not turn out well if that plane gets ramped.
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Perhaps you should check the regs on this. The requirement to have knots primary came out a year before the requirement to have a POH, so I don't see a problem with the mph plane not having an applicable POH.
 
CTLSi said:
Like I said, you should ALWLAYS be watching your IAS airspeed when changing your flaps, when in cruise, when dealing with Va, and especially when entering base and then to final.

When over the threshold you should have a number NAILED... If you fly the numbers you can transition easily between glass and steam. In the glass cockpit the arcs are barely noticeable.
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Checking briefly is one thing, but "watching" it is another. You should be looking at attitude, not airspeed, as you approach the runway. If you nail the attitude, airspeed will take care of itself (including correction for weight), but if you are "watching" the airspeed, you aren't paying attention to the runway, glide path, drift, or other airplanes.
 
Halfway through the white arc in my plane is 80 MPH, and nothing about the amount of flaps or bank angle is going to change that. I hold that until I'm "over the fence" and then I start rounding out and letting the airspeed drop off until the plane settles. I'm never anywhere near the stall.
 
murphey said:
If you own the airplane, simplest solution would be to replace the airspeed indicator. Older cherokees have airspeeds with mph on the outside ring and kts on the inside ring. Makes for interesting discussins with people not familiar with it.
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Unless the airplane needs MPH for some dumb paperwork, like ours.

We have a dual MPH / Knots ASI because the Robertson STOL STC Addendum is in MPH. We've been told we must keep it or always have a dual indication variety. Whether that's true or not, I haven't dug that hard.

Not too hard to find dual-indicating replacements, so kinda a non-issue. But there is a reason we have that goofy thing.

(We converted the Robertson numbers ourselves to knots a looooooong time ago. But they're not "legal" so they say...)
 
I had a 1966 C172G that had an ASI in MPH. But the POH was in MPH also so I just left it and recalibrated my brain for that airplane.

If I'd had the money I might have put in a new ASI that read both MPH and KIAS.
 
DesertNomad said:
My instructor trained me in a 172N (40° flaps and MPH) and a 172P (30° flaps and KTS). We are in a high desert environment.
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Interesting. The C-172N I learned in (and still fly) is in Kts. ASI and POH. Built in 1976. Only has 30 degree flaps due to the 180 hp Penn Yan mod. Love that 250 pound bump in max gross. :D
 
Yeah, I thought all the N's were in knots. Some M's were in knots, some in MPH.

I had the good luck to fly an M that was in knots.

More recently, a 182P with an ASI in MPH. That's a mind****. The instructor that came with that airplane had an approach to that that I've never heard elsewhere. It's to set a 182 to 14 inches MP abeam the numbers, and pitch for 500 FPM descent. Re-trim for 500 at each notch of flaps. Then, the speed "takes care of itself" (but of course I check it). Adjust approach height with throttle and adjust for 500 FPM again. In practice, I seem to chase the VSI needle a lot, and cross the fence a bit on the fast side even with 40 deg flaps, so I'm not sure I buy it.
 
Ghery said:
Interesting. The C-172N I learned in (and still fly) is in Kts. ASI and POH. Built in 1976. Only has 30 degree flaps due to the 180 hp Penn Yan mod. Love that 250 pound bump in max gross. :D
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Sorry - the 172 I had in mind is a 172M (1974)… which is in MPH. Looks like the 172N moved to KTS.
 
MAKG1 said:
Yeah, I thought all the N's were in knots. Some M's were in knots, some in MPH.



I had the good luck to fly an M that was in knots.



More recently, a 182P with an ASI in MPH. That's a mind****. The instructor that came with that airplane had an approach to that that I've never heard elsewhere. It's to set a 182 to 14 inches MP abeam the numbers, and pitch for 500 FPM descent. Re-trim for 500 at each notch of flaps. Then, the speed "takes care of itself" (but of course I check it). Adjust approach height with throttle and adjust for 500 FPM again. In practice, I seem to chase the VSI needle a lot, and cross the fence a bit on the fast side even with 40 deg flaps, so I'm not sure I buy it.
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14" is too high in mine unless you're dragging it in. And it's too fast for 500 FPM on an approach.
 
Nailed this stuff (sort of) yesterday. I went for a flight in the evening when it was calm so I could figure it out.

I figured out the trim, which is very different from my previous experiences. Once I figured out the sweet spot on trim, she lands herself, all I have to do is a flare. It was interesting and exciting at the same time. She flies herself at 75ish mph until I put some very minor effort into a round out followed by the flare.

I took my CFI with me to help me spot something I'm missing and figure out what I need to do to refine it. His remarks were "thats the right speed" and "if were having a contest for a precision landings you just won".
 
gitmo234 said:
Nailed this stuff (sort of) yesterday. I went for a flight in the evening when it was calm so I could figure it out.

I figured out the trim, which is very different from my previous experiences. Once I figured out the sweet spot on trim, she lands herself, all I have to do is a flare. It was interesting and exciting at the same time. She flies herself at 75ish mph until I put some very minor effort into a round out followed by the flare.

I took my CFI with me to help me spot something I'm missing and figure out what I need to do to refine it. His remarks were "thats the right speed" and "if were having a contest for a precision landings you just won".
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There ya go.

Now start betting Cokes on whether or not he can call your touchdown spot and you hit it. ;)
 
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