Crabstick

Hi guys

I am wondering about possible techniques to land the low wing cap, its a 1m wingspan ep - I have a turnigy 3536c 1100kv with an apc 11X4 slowfly, hyperion titan 30a and a 2200mah lipo - plane weighs about 700 grams, and i have got flaperons - but havent used them to land yet

it flies beautifully as its overpowered and unlimited vertical is an understatement, but the first three landings i managed to flatten the landing gear - it doesnt land like my e-starter or 3d sukhoi profile :P

what point if any should i start dialing in some flaperon ? how much, what sort of speed should i be landing at?

cheers

Matt

aussiesteve

Just remember when you are landing the following applies
Throttle adjusts your Rate of descent
Elevator adjusts your forward speed (and therefore where you will actually touch down).
I know those rules are very simplistic but think about it. Airspeed creates lift so use the throttle to control the sink rate. the elevator will control the attitude of the plane - If the nose is high, you will need more throttle to keep the plane airborne but the forward speed will be low (think of a Harrier). - the reverse also applies.

Use your throttle to fly towards where you want to land. Adjust your speed to control your rate of descent and keep the rate of descent low. When you are very close to the ground (About a foot), reduce the throttle to idle or zero.

Campy

My Feedback: (1)

A CAP is similar to a warbird for landing - you need to keep some speed/power on otherwise they tend to snap.

Crabstick

Should I try and use the flaperons at all ? or leave them out of it.

I think i was a bit scared of the approach speed and tried to flair it a bit to scrub off some pace. might see if I can sneak a flight in after work tonight and practise my landings

Campy

My Feedback: (1)

My personal preference is for regular flaps over flaperons. I have not had good results with flaperons, especially if I have had to do any wing leveling.

Someone told me that using the ailerons while the flaperons were deployed did not allow "adequate" movement of the ailerons AND created uneven drag - ie, producing uneven lift and also creating a "turning" effect on the plane.

I don't know for certain. I did 2 flights with flaperons and was NOT HAPPY with the way the plane performed while landing. They were converted to regular flaps and I was substantially happier with the performance and handling of the plane while landing - the plane was a lot more stable, especially if there was a crosswind.

aussiesteve

I agree with Campy on that one. I'm also not much of a fan of flaperons. As soon as you use them you are altering the wing shape to increase lift. Then when you go to use aileron control you not only remove the additional lift from one wing, you increase it on the other wing. The differential drag he mentions is also real.

However - here's another thing to consider, it comes from full sized flying and is easier said than done to try it on RC planes. Use the rudder instead of aileron to control wing drop from such things as crosswinds. This applies especially if you are using flaperons (which are not often encountered on full sized planes). Try it up high and see!! In simplistic terms - you want to speed up the low wing to increase its lift. So if the port wing drops, apply starboard rudder to lift it. At the same time you will be turning into the wind and will introduce some side slip to get you on line for your landing - Please note - I did say it is easier said than done to train oneself to do this and often you will need to use a combination of aileron and rudder with rudder being the major input.

(For those of you that are wondering - yes I have flown a lot of vintage full sized planes but they weren't quite as vintage in those days)

Crabstick

thanks Steve and Campy

i could cut down the ailerons and go to dedicated flaps, but that would mean another 2 servos in this plane - id say by then i might be sucking all the juice that my bec can supply and it may be a bit much work for this plane


one other thing though - I have the flaperons hooked up to the dial on my TX so can dial in just a little bit - will try that up high and see what the glide/stall performance is like

Have either of you flown a GWS spitfire ? what do they land like ? would it make a good low wing landing trainer ?

aussiesteve

I've never flown a GWS Spitfire but by the reports I've heard they are pretty good fliers.
They would probably make a good Low wing landing trainer - especially to get you used to the higher landing speeds that may have daunted you a little so far.

One trick that I use to get people familiar with higher landing speeds is to get them to land further down the landing area than they are standing so they are looking at the tail of the plane. I mention this for small planes on large landing areas it isn't good if the landing area is only just big enough to use for the plane you are flying. That way, the plane is moving away from you and the speed isn't so daunting. The minus is that you are wasting some of the landing area. The plus is that you learn to make accurate landings with less chance of a go around. As you get used to it, move your landing point further up the runaway - a little bit each landing and before you know it you'll be landing while looking at the nose of the plane and not thinking twice about it. I hope that description makes sense.

Nathan King

I agree that flaperons are not necessary for the airplane. It sounds like you just need to practice approaches and landings. Less than stellar technique that remains hidden by forgiving airplanes can easily be brought out into the forefront with a more demanding model.

The asymmetric lift and drag does not just occur with flaperons; it is simply a fact of aerodynamics. The aileron descending on one side increases the camber of the airfoil (changing the chord line), which simultaneously increases AOA and lift. Because of the increased lift, you will always have increased drag on that wing as well. Lift and drag always come in pairs - there's no separating them. Of course, the other wing does the exact opposite. After all, without asymmetric lift and drag you wouldn't be able to bank the wings and wouldn't need a rudder.

Nathan King

The rudder tip is excellent. Ideally, when you are approaching the runway the only thing the ailerons will be doing is keeping the wings level; however, due to gusts, turbulent air, thermals, etc one wing may dip. At landing speeds with an aircraft such as a Cap 232 the rudder should always be used to counter this dipping. There's a mathematical reason why, but I won't bore you with the intricacies of it. Suffice it to say that most pilots that experience "snapping" don't heed this advice and use the ailerons.

Crabstick

I use the rudder a lot as I fly helis so planes are quite relaxing to fly as they dont require as much input. I will take that tip and use it, thank you! Didnt get out tonight as its blowing 25 knots and raining, oh and dark!

its now rugby season so i have goalposts to contend with, I may go learn to land this thing at another park that has no trees, goalposts and a lot more space. One spot has a 100 meter atheltics track that works as a nice sealed runway and a few guys fly out of there, should be easier to do power landings as the ground is a lot smoother and im only sporting some little wheels.

thanks for all the info guys, will makes this learning curve a lot quicker!

Cheers

Matt

Nathan King

That's cool that you use the rudder. Most of the guys at our club just think the left stick either turns the engine on or off.

A little over 300 feet should be good to fly the Cap from. Landing may be a little tight depending on if you can spot land the airplane toward the beginning of the runway on a regular basis.

Cool, have fun!

marktur

Hi - A Cap is not a trainer. This is a full-fledged aerobatic airplane, and it's power source (glow or electric) has nothing to do with how it flies. Caps have always been a fast-flying aerobatic plane - NOT a sloiw-flying 3D plane. It is great to use for IMAC style of flying. (Yes, I understand that you can overpower just about anything and make it fly 3D, but your question indicates that you're possibly new to flying or this type of aircraft.

I would suggest a few things to help you out:
1. Do NOT use flaperons. They change the shape of the wing and things simply "get mushy" as speed slow down. This leads to over-controlling the airplane at too slow of speeds. Caps LOVE to snap at slow speeds. It's a real formula for error.

2. Real Caps do not have flaps - so take a clue from the full-scale brother.

3. Come in a bit higher than normal, and plan on getting it to about 1-2' off the runway at the BEGINNING of the runway. Since you're coming in a bit higher, you will increase your airspeed as you dive (shallow) for the end of the runway. Once you've leveled out, let it down more, and the goal now is to let if fly about 3" off the ground, no power, fuselage LEVEL with the ground. Be patient, let the airspeed drop, and you will be rewarded with a nice "wheel" landing. Continue letting it roll until the tail settles down by itself, and then you can hold in full up elevator while you taxi back.

A good way to practice this technique is by extending your takeoff roll all the way to the end of the runway without taking off (until the very end - when you have tons of airspeed). It takes some skill not to trash a prop OR come off the ground, but when you can do it, you will never ever "think" about taking off and landing again - it becomes natural.

Hope that helps - I had a GP Cap 21 in a previous life (about 25 years ago) and I had the same questions and problems, and this was the advice that my trainer told me. When I got my first warbird (a 60-size Corsair) these skills REALLY helped, too!

Good luck,
Mark

feihu

Matt:

You should learn how to slow fly your airplane. How do you suppose Jets land?

Suggest you go to altitude and set your powerhouse motor at about 1/3 throttle and pitch trim the airplane to fly level. Fly around for a while maintaining altitude and doing shallow turns until you are comfortable with the handling. Then without changing trim, add a bit of power to make gentle climbs, and decrease power to make gentle descents.

Then fly a traffic pattern using power to descend and land. If you feel the trim speed is still too fast (too much float before touchdown), then go up and practice at a slower trim speed and try again.

I'm assuming that you wingspan is about 40 inches, and average chord about 8 inches; so at 24.7 oz (700 grams) your wing loading is about 11 oz/sq ft. Applying Kieth Shaw's formula, your Cap 232 stall speed is about 15 mph and a good approach speed for landing would be about 20 mph.
Don't know if these numbers mean anything to you, but if you can find the trim speed of your airplane of about 20 mph, you would be able to use the throttle to control your descent, and with a touch of the elevator to flare, you can have a consistent good landing every time.

This is applying what aussiesteve is telling you in the post #2 above.

If you try it, you might like it, and you might continue to use it!

feihu