If I switch props will it slow me down on approach?
 

I tend to land quite hot, too hot. I can make her slow down up high, I even practiced stalls so I would know just how slow was safe. But I cannot get it to slow down on approach, when I try I simply climb back up even at idle! Of course this slows it down, but then its too high for a good landing. (She speeds up on descent)

Soo, Iwas wondering if switching propellers was in order. I run a 10x6 now, if I went to say an 11x5 or 11x4 would this help? or am I just gonna have to learn to make my approaches from lower altitude so I can keep the speed down?

Any advice here is apreaciated even if its totally off the propelelr subject, just need to figure out how to slow down LOL!!

RE: If I switch props will it slow me down on approach?
 

I have seen alot of posts on flying or landing with the wind lately, so are you landing against the wind like you should?

RE: If I switch props will it slow me down on approach?
 

Most times, NOW I am anyhow. The east end of the runway has a tree line close so originally I landed only one way to avoid it. I taught myself to come in from that end recently because of althe posts here on landing into the wind rather than with it. Yesterday we had a nice 3-6 knot head wind from east to west so landing from my usual end was preferred, and I STILL landed long! (Moreso than usual I think)

This is why I decided to ask here, I am not sure how to both SLOW down, and COME down at the same time. I can do one, or the other with sufficient airspace, but not both in the amount of space available. (From west to east theres PLENTY of airspace to glide in from over a runway length out, and we've a 500' runway)

RE: If I switch props will it slow me down on approach?
 

Sounds like you've gotta throttle back sooner. Different planes slow at different rates. My trainer I chop from 1/4 to idle about 1/2 way thru the base leg. My mustang needs to be chopped to idle much sooner, as there's alot of speed to bleed and no drag to do it with.

We say that we control the speed with the elevator and the glideslope with the throttle, and that's true, if you do it right. But if you try to slow the plane "now" with elevator, it will convert the speed you have to altitude.

Try planning your landings so you will not make the runway if you just go with it. Then add a click or 2 of throttle to stretch the glideslope a little longer so you make your intended touch down. A little goes a long way. This is how the full scale guys do it. It's impossible to loose speed quickly, but it's easily added.

THis is a skill that's both easier and harder than it looks. We all do approaches around and above obstacles, and there's a pucker factor to that. But in time, you'll become more comfortable with what the plane is doint, and suddenly you will wonder why it was so hard yesterday.

Kinda like driving stick. I can't make one jackrabbit now for the life of me. Used to be the other way 'round!

J

RE: If I switch props will it slow me down on approach?
 

Perhaps a 9x6 Three-blade?

RE: If I switch props will it slow me down on approach?
 

Also double check the CG.. I've had planes that landed way hot and moving the CG back a little helped quite a bit.

How does it stall? A clean break or a mushy nose over?
Also when you are landing is it taking almost all of elevator to make it flare?

When its running on the ground will it stay still at idle or is it always trying to roll away?

RE: If I switch props will it slow me down on approach?
 

The approach info is good, Ive always thought that if I came in too low it was a bad thing, but from what you said, its easier to add power to extend the glide than to slow it down if you overshoot.

CG: checked it, I'm roughly 1/4" behind manufaturer suggested CG

Stall: Sort of mushy nose over, at least when I really put her into a sharp up angle to do it.

Flare: Well, Im still learning when to do this so sometimes full up too late! bang / bounce, and sometimes (when I get it right) just a smidge as she settles and she rolls out, when I time it right if I give too much in the flare she goes right back up though.

Still working on the tune, so she idles a bit high right now, but when I can get it to idle right it doesnt move.

Note: Im amazed at how much adjustment I needed to make just from going to a new can of fuel! (the old stuff was 6+ years old so I expected to have to adjust but WOW!) I suspect I have over adjusted and need to come back down, but Im afraid to run it too lean.

RE: If I switch props will it slow me down on approach?
 

A second note: I have discovered thru observation that I may have too much down thrust. As some of you may know I had to rebuild the firewall once, and I remember my first instructor commenting that it had quite a bit of downthrust in it.
I believe too much because when I power up to go around, if Im not right on the elevator the thing will drop like a rock for two feet or so from the full power rev up. Im considering different ways to shim the motor mount, or simply rebuilding the firewall again this coming winter

RE: If I switch props will it slow me down on approach?
 

That can be a sign of excessive down thrust.

Those finer pitched props may help, but you should be able to slow down fine with a 10x6. What RPM are you turning at idle? It should be 2000-2200 RPM. I'm not sure if this is happening to you, but most beginning pilots try to come in WAY too fast with their nose pointed at the runway instead of a nice nose-high attitude.

RE: If I switch props will it slow me down on approach?
 

So what airplane/engine are we talking about? Your profile shows a Hangar 9 Arrow Trainer 40. Is that the one? High wing trainers should have little problems slowing down - if you have your engine tuned correctly, your CG located correctly and the proper propellor selected. Going from a 10-6 to 11-5 prop will help out a bit. What's your idle speed?

Biggest friend in slowing down is to fly when it's a bit windier outside. Your model's groundspeed is very fast going downwind but quite slow when heading upwind. It's harder to spot land a model when it's dead calm out. A noseheavy model will always be diving.

RE: If I switch props will it slow me down on approach?
 

Yes its the Arrow, my profile is accurate on the plane in question.

As for idle speed, I dont have a tach, but Ive heard many well tuned 2 strokes idle, and I try to tume to getthe same pitch / cylce sound. While Im no expert with these engines, a n00b actually, I know sound well, I was a sonar tech in the navy so Iv had lots of practice discerning different sound pitches and such.
Right now, (As of yesterday after two hours and a full tank of gas tweaking) she idles so that it wont move, BARELY; but I have to goose it occasionally or it loads up and dies. (At least thats the term I was told it was doing) This of course gets it rolling.

Bummer of it all is before I opened my new can of fuel she idled great! I think the last dregs ofthe 6 year old stuff was bad because that last tankful from that stuff is where I started having dead stick issues, (three in one day not counting the out of gass dead stick). I defueled it and tossed what was left of that, refueled with the new stuff and retuned, 15 minutes of tweaking got me farther than two hours with the old stuff. (Actually it was half the old and half new because I ran out on that gallon half way thru fueling up.)

RE: If I switch props will it slow me down on approach?
 

Sounds basic but do you need to re-trim your throttle adjustment? On my first day of soloing I was coming in so hot I couldn't land; I tried maybe 5 approaches and was just CRUSING over the strip. A guy next to me said to lower my throttle trim. Sure enough, after I got it down I checked out my settings in the pit, and was able to drop 300rpm off my low end just my using my trim switch.

Another thing that I do is when flying the opposite direction, just before base, make some extra turns but don't lose any altitude ( maybe this is called 'tacking'?) - if the wind is pushing you, this will help because you will be using some of your energy to fight the wind, instead of using all of it with the wind. Hope this makes sense.

RE: If I switch props will it slow me down on approach?
 

Throttle trim is how I lower idle, (obviosly tuning the motor so it will run at this setting LOL)

RE: If I switch props will it slow me down on approach?
 

A proper glideslope, as they do with the real planes, is sometimes hard to accomplish, since most aero-modelers fly in less than ample runway conditions, in regards to glideslope. Too many obstacles at the end of the runway. A forward slip to landing is a great thing to master when you have a crosswind - anything from 15deg to 90 deg from the runway. It allows you to bleed off altitude, and establish a good descent rate upon rollout. Tip the wing in to the wind, and apply opposite rudder, to allow the plane to maintain a ground-track with the runway. It's not a beginner maneuver, but I'm sure an instructor would be more than happy to teach it to you.

As for excess airspeed - I have the same problem. I have an Alpha 60 with a .91 4-stroke, and a 14x8 prop. I can barely keep it still on the ground. My radio (Futaba 8UAP) is set for a High-Low-Off Idle, with a 3-position switch. I haven't quite got it fine tuned. Essentially, I have High-Idle for flying. Low Idle for takeoff and Landing, and Off. On landings, it can be somewhat a hassle to reach up and move the switch to Low-Idle, and on occasion it will dead-stick on me. I've gotten to be a pro at dead-sticks, and don't really mind them. I can't exactly tell you how to over come the airspeed issue. Getting the idle set right is key, but another part of the skill is learning the glideslope that works best for your plane.

When you practice slow flight - try doing it without changing the altitude of the aircraft. Stalls are the result of a loss in lift - in short. A plane will stall at any attitude!! Whether nose up, nose down, wings level, or wings banked, it will stall in any attitude. It's best to practice "flares" and controlled stalls from altitude, and even private pilots practice stalls - both with power and without power. A private pilot is supposed to perform the stall without losing more than 100ft of altitude and must maintain altitude within +/- 50 ft while entering the stall. Try to perform the same maneuver with your scale trainer, and understand what you should hope to gain from it - A controlled stall, that is entered at an altitude of XXft, and exited at XXft, while not losing more than XXft. If you apply the same training to a landing - A flare is a controlled stall executed just prior to the moment of touch-down, but doesn't actually reach the 'full-stall'. Throttle is supposed to be used to control descent rate, and the elevator is used to control the pitch attitude and airspeed of the aircraft. The problem with that in aeromodelling is that it is sometimes hard to determine proper glideslope, pitch attitude, and airspeed. There aren't any VASI's!! But if you can master the flare, and controlling airspeed, your landings will improve remarkably. Keep in mind - the forward slip to landing is a way to lose a lot of excess altitude, maintain alignment on the runway, but should also be accomplished once you have found the proper throttle settings for landing.

I would suggest that you ask an instructor to assist you in slow flight maneuvers, especially power-off stalls (power-off stall is a stall performed while at idle throttle - don't turn it off!!), and after you feel comfortable with them, ask him to teach you the forward slip to landing. I would not do the forward slips to landing, without being taught the maneuver by an instructor.

RE: If I switch props will it slow me down on approach?
 

The good news is that a lower pitched prop will slow you down. When I'm flying 40 sized planes with one of my 52 four stroks, my faviorite prop is the APC 12 1/4 x 3 3/4 prop. Cutting the throttle is like setpping on the brakes. You just have to watch it that you don't slow down to slow. Remember, air speed is what is important. You generally judge the planes speed by it's ground speed and what looks like enough speed can turn into a full fledged stall very quickly with a gusty change in speed or direction. The great thing aoubt the low pitched props is that the let you come a little hotter and then hit the brakes just before landing. If you can get your engine to idle at 2500 or less and still respond to a sudden need to power up and go around, you should be good for most any wind condition that you can fly in. The low pitch prop also gives you a lot of acceleration when needed. If you want to go really fast, its not a good choice though.

Don

RE: If I switch props will it slow me down on approach?
 

I believe that the main problem is the tuning of your engine, if you do not own a tach. you will know that you have excessive rpm at idle when your plane wants to run at idle in a paved runaway. Your trainer should stay still at idle (with out holding it). You are using the correct prop. 10 x 6 is perfect. Down trust should be checked but it is not a problem when you are at idle in a landing attitude.

RE: If I switch props will it slow me down on approach?
 

Just verify that you 1.) control speed with elevator and , 2.) control sink with throttle.

One common mistake is to chop power and attempt to glide in. This results in a much higher landing speed.

RE: If I switch props will it slow me down on approach?
 

I was having the same trouble today. And this is in a nexstar. I switched to a 10X6 prop from the stock 11X5 and it always seems to come in fast now. I have the idle chopped real low and the only thing that really helped today was cutting to idle dropping all the altitude I could then bring her back up to lose more speed then begin my landing approach. Changing props changed the characteristics of landing quite a bit. It just seems to not want to slow down now.

RE: If I switch props will it slow me down on approach?
 

Hmm, I/we are all trying to help you land with the prop you have. I just realized I didn't answer your original question, though - yes, if you switch props it will help slow you down on approach. An 11x5 will slow you down a little, and a 12x4 even more. The larger diameter props with the lower pitch number will give you lower overall speed, but more low-end power, i.e. 'get up and go'. They will give you better climbing, and pull you out of stalls better, sacrificing top speed.

RE: If I switch props will it slow me down on approach?
 

THIS is 3/4 of my problem, I was taught to land exactly this way, I chop throttle on the base turn and come the rest of the way in at idle usually. I've read your points several times here, but cant seem to get my hands around the concept that my mind understands in theory. Every time I try it, (at least once per visit to the field, usually once per flight while attempting touch and goes) I end up WAY too high from too much throttle, and have to go around. More practice is order.. (Aww thats SUCH a Bummer!! Gee whiz I HAFTA fly my plane 'cause I need practice[>:] )

As for the lower pitch prop reducing top end, well the only time I fly at full power / speed is in a climb anyhow, more often than not I'm at 1/2 or less. (I usually go full throttle to climb in prep for a loop or a roll, but when looping I chop to half or less at the top.) That it will give me more pull to recover from a stall is probably a good thing because it means if I slow down TOO much i have a bit more raw pulling power to climb out of the stall. Next time Im at the hobby shop I will pick up and 11x5 prop, unfortunately I don't think Ive the ground clearance for a 12 incher, and larger wheels aren't in the budget yet..

RE: If I switch props will it slow me down on approach?
 

The 11x4 is a good prop for .40-.45s and will make a dramatic difference. The flat pitched blades turning at less than XX rpm create a lot of drag. To the oncoming air the prop looks more like a solid 11 inch diameter airbrake than a higher pitched prop will. The 11x4 will improve your thrust over a 10x6 and make managing the throttle less critical.
The main drawback is that you will probably grind up more 11x4 APCs than you would 10x6 MASs.

RE: If I switch props will it slow me down on approach?
 

Okay dokay . You are chopping power too late. Try the middle of downwind or even the beginning of downwind. By the time you start your turn to base, you should already be holding in a touch of up elevator. Once you have turned final, and no more turns are required, you can slow down even more with slightly more elevator. Don't worry about being short, you can always add a click or 2 of throttle if needed. This will...........anyone?,..........slow your sink rate and cause your glide slope to end at the runway.
Trainers float like gliders. It isn't always practical to carry throttle on final with such a lightly loaded model. The difference between gliding and a powered appraoch might be a single click of throttle. But the idea is to raise the angle of attack of the wing. This causes more lift to be generated at the same speed or for the same amount of lift to be created at a lower speed. We want to create the same amount of lift, but at a lower speed. More lift means more drag being generated. More drag being generated means more thrust is required to maintain speed. This is really easy to accomplish with heavier , faster models. Its a tad more difficult to find that narrow zone on a trainer. The darn things just climb away, as you experienced. But stick with it. You can find that zone.
And this is what you want to practice. IT prepares you to land the faster, heavier models later. IF you rely on the prop doing all the work for you, then you aren't going to learn what you need to learn. Make sense ?

RE: If I switch props will it slow me down on approach?
 

[/quote]

Okay dokay . You are chopping power too late. Try the middle of downwind or even the beginning of downwind. By the time you start your turn to base, you should already be holding in a touch of up elevator. Once you have turned final, and no more turns are required, you can slow down even more with slightly more elevator. Don't worry about being short, you can always add a click or 2 of throttle if needed. This will...........anyone?,..........slow your sink rate and cause your glide slope to end at the runway.

[/quote]

I think I agree - where is your throttle on the downwind leg? If there is like more than 10mph wind, I'm usually less than 1/4 throttle, even pretty close to idle. Then I increase to about 1/4 throttle for base and approach to final coming into the wind. If there isn't much wind, do the entire downwind leg at 1/4 throttle, lose a click or two during base, and another click or two on final, so you're coming in maybe 2 clicks above idle (assuming your plane really likes to float, otherwise come in with a few more clicks of throttle - I was flying the Nexstar and Avistar at 1/4 throttle until I past the apron of the landing strip and was maybe 3 feet off the ground, then cut to idle).

Hope this helps.

RE: If I switch props will it slow me down on approach?
 

Point not yet covered among all the other good advice:

Since you're having problems getting rid of speed, practice getting rid of speed too early. Cut your throttle to idle when you start your down wind leg. Now try to hold the altitude by adding elevator. Slowly add the elevator until the plane has established a slightly nose up attitude and is losing altitude. That is, the plane is now in a condition where it is losing altitude with the nose pointed slightly up. This is your landing condition! Now if you want to add altitude, just give the throttle a quick bump (one or two clicks for a second or two). You should be able to control the plane easily in this condition all the way around the field.

Now learn to let the plane lose the altitude and learn your glide slope to reach the runway in this condition. This is the hardest part for beginners to learn. There is a natural tendency to try to keep the plane as high as possible as long as possible. You must conciously fight this habit. Learn to fly the plane low and slow on approach, and you'll soon be greasing your landings.

And don't forget to tune the LOW end, not just the high end. That will affect you're lowest reliable idle the most.

Brad

RE: If I switch props will it slow me down on approach?
 

Do the math.

Example: 10,000 rpm with a 10-6 prop. The prop has a 6” pitch. This means that it will move 6 inches for every revolution. So, at full throttle, the prop will move 60,000 inches in one minute. 60,000 inches is roughly one mile per minute or 60 miles per hour. This is at full throttle. At half throttle, if it is linear, you will be doing half that, or 30 miles per hour. Quarter throttle, again if linear, 15 miles per hour.

So, judging on how fast your engine is turning at the time you land will tell you how much your prop is working and how fast you are going. Just substitute the numbers for your prop… if it’s a 10-8, for instance, the difference will be noticeable. That becomes 80,000 inches at 10000 RPM or approximately 75 miles per hour at full throttle, and so on.

Again, that's for 10,000 RPM. Again, do the math. If your engnie idles at 3000 RPM, then see what it is doing with your prop. Don't forget to factor in the wind effects and the glide slope, and how much it slows down when you do come in on approach.

Land upwind.

CGr.