fturna

Hi,

I have a brand new P51-D Mustang (used O.S. .91 FX instead of the suggested .61) and have made just 4 flights so far. I am getting familiar with my mustang.My question is how to use the flaps ? How much mixture with the elevator will be correct ?And so on..

Many thanks,

Fatih.

Tall Paul

I'd suggest using flaps only when landing. On mine, the flaps go down about 45 degrees, and add a lot of appeal to the look of the plane.
They're unneccessary for takeoff, and would be a potential problem there due to flying too slowly..
On landings, set up a good rate of descent.. Don't try to float the airplene, it will tip-stall... and Mustangs don't glide anyway.

MinnFlyer

My Feedback: (4)

45 degrees sounds like a lot! 20 to 30 is more like it.

Aside from that I agree with Paul, only for landings. Also, I never use an elevator mix. when you lower them, do it gradually. The plane might balloon a little, but usually only for a second. But that's expected... you just increased the lift and the plane hasn't had a chance to slow down yet.

Soon it will slow down nicely and allow for slower landing speeds.

Also, as Paul said, don't expect it to float... but I'll add - don't be surprised if it does. I used to have a GP Mustang 40 that I added flaps to, and it would float like a trainer.

JL1

My Feedback: (93)

Flaps will let you make a steeper approach without picking up excess speed. They add a LOT of drag and your model will really slow down when you drop them. My technique is a steeper than normal approach with power on (maybe 1/4 or 1/3 throttle), pull up into your flare and fly it to the ground. I don't reduce power until just before or at touchdown. Once you get used to them, they are very useful as the steeper, nose down approach angle reduces the chance of a stall. What ever you do, don't try a long, flat approach. It will require a lot of power to keep your speed up and if the engine flames out, your sunk.
Something that is fun to do (and watch) is the military approach where you fly down the runway lengthwise at medium speed ( at pattern altitude), "peel Off" and circle around to your downwind leg while dropping flaps and gear, fly a circular descent to the runway and touchdown. The military did this to minimize their time (and vulnerability) when landing in wartime.

paladin

My Feedback: (9)

How to fly flaps. The first question I have for you is how confident are you with your ability to recover from a stall. Not because flaps will cause a stall but in order to fly them correctly you need to establish your stall speed with them deployed. Now I’m not telling you to go out and do spins with flaps, just that a little knowledge goes a long way.

I set up all my flaps to deploy to 50 degrees and usually only use about 45 degrees. Having a control surface that has a total range of movement of 50 degrees puts us at risk of poor repeatability at the limits, which is were we plan to use it. So you need to test your firmness at the deployed and flying position. While firmness is not so important in the flying position just like with any other control surface if there is free movement it will seam like your aileron trim is changing as you proceed with flaps. If you have solid control of the flaps you are ready to fly with them.

When ready to try the flaps reduce to half throttle and let the plane bleed some speed off. Then add the flaps (I have them on a proportional switch, most everyone new to flaps has them on a on off switch) the nose will come up at first but as the plane slows the nose will return to level. During that process you will have to adjust the throttle to make it fly level, not the elevator. You are looking for a throttle setting that yields the same elevator trim setting you had before adding the flaps. Once you have it set so it is doing level flight with the lower throttle setting fly it around for a while that way. Notice that its attitude has changed, its flying considerably nose down, when throttle is added without changing the elevator trim it will climb, also turns can be achieved at much lower banks. Then try adding throttle in turns (a lot at first to see the affect), you should see that the turn tightens and the nose comes up ( once comfortable with the results of this limit your self to 4-7 clicks, and note the response).

The last thing we need to talk about is the correct way to approach the runway. You want to plan your approach so that you can reach the runway in case of an engine out. Never remove the flaps on an engine out! Point the nose down into a steep dive to maintain speed while turning to the field immediately and do not level off until you are ready to touch down. Some people like to dive in level off then flair, while others like to use the shallow approach. I like to set up the down wind high enough to reach the runway on an engine out then loose altitude during the down wind turn and approach gradually until I find my self level with the ground. The approach you use is up to you and your preferences.

Your approach will look different to you no matter how you make it! The plane is flying nose down to start so even a shallow dive will look steep! So pay attention and it is perfectly OK to over shoot. If you overshoot go to ¾ throttle and the plane should start to climb away. Once everything goes right you will find your self a couple of inches off the runway and itching to flair. Don’t! reduce the throttle to idle and hold that attitude (don’t flair).

This is the toughest part of flap landings to get used too. With the flaps the plane flies nose down, you saw it earlier when you were flying it around with flaps. That means that if you pull level to the runway you are already in a flair. The plane should look like it is tail high at the point were you want to flair, and only experience will teach the correct blending of elevator and throttle at this point.

Good luck! And have fun with it once learned, landing with flaps, it’s the only way to land.

Joe Felice

paladin

My Feedback: (9)

I forgot.

As you are flying around you will notice that it needs some aileron trim to keep it flying level. This is usually caused by one flap deploying just a bit more than the other. Trimming it out is perfectly acceptable as long as you remember to reset the aileron trim after landing. If you forget you will remember after the takeoff for the next flight. You can tweak the linkages to get them aerodynamically right but this takes time and a good understanding of linkages and how they play against each other. The easiest way is to buy a servo centering lead, many times servo reversers come with a servo centering option. Anyway this thing goes between the “Y” harness and servo lead on one side and you just turn the pot to change the center point of that servo until the role is gone.

I’m sure you are asking how bad can this role be? The first time you put the flaps down you will be to excited to notice it, but as you put time in you will notice it usually 15 to 30 degrees of role in 10 seconds real minor. But when you are doing your first flap landing best to know what is going on.

Good luck

Joe Felice

Tabdy

I use Flight Modes with my Flaps. This allows me to have independent trims locked to each flap position. At a safe height I select full flap with motor at whatever I want to use for the final approach, but more often than not I will select idle, I then gently adjust elevator trim to give me the glide approach I want.

Thereafter I can turn onto finals, select full flap and know that the neutral stick position is going to give me a safe approach speed which I can then adjust depending on power and margin I have allowed from stall. This seems to work for me for all types - having struggled a bit and stalled to destruction on occasion when turning onto finals or slowing too much on finals.

I'd be grateful to hear other's views on this way.