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Where in the final circuit to lower flaps?

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Adrian Hazeldine31/05/2020 20:41:16
23 forum posts
1 photos

I've started flying some 60 size warbirds with flaps but haven't plucked up courage to use full flap on landings yet.

Can I ask for views on where in the circuit to go to half flap and then full flap as I've heard lots of bad stories about the perils of lowering them too early.

thanks!

Chris Walby31/05/2020 20:59:58
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1246 forum posts
308 photos

What's the problem with lowing flaps too early... unless you don't compensate for the additional drag?

I find that lowing gear tends to cause a pitch down and 1/2 flap a pitch up so as I come past the flight line for the last time its gear down and flaps 1/2 at the same time That way I can see all the gear is down plus it gives me the down wind leg a bit of time to get the feel of the change in how it flies.

I set the flaps to deploy at the same speed as the gear going down.

Another model that has fixed gear has a mix of flap to elevator as there is quite a pitch change, but that's for mid throttle position as it pitch changes a bit with throttle (climbs on full throttle).

IMHO its best to keep your workload down in the down wind lead and final turn + it means I am not tempted to fly an extended down wind leg and do everything on approach with its being harder to judge air speed being a long distance away.

Others might have better ways wink

PS practice flap deployment at 3 mistakes high and get a really good feeling on how each model behaves with the various flap settings.

Adrian Hazeldine31/05/2020 21:10:22
23 forum posts
1 photos

Chris, thanks for this. When would you go to full flap - when you've turned onto finals?

SIMON CRAGG31/05/2020 21:19:41
575 forum posts
5 photos

Another good tip is to activate "servo slow" on your TX.

Deploying 40 degrees of flap in one go, can cause all sorts of problems.

With servo slow, it gives you more time to sort out your throttle / elevator contol.

Have to say, I have seen a LOT of models come to grief by slowing up to much on finals, triggering a fatal tip stall.

Practice at height first..............and good luck!.

bert baker31/05/2020 21:53:51
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1609 forum posts
331 photos

Full flap landings,

One of my fun things to do with my 45cc Blackhorse Chipmunk is to go up high and when above the runway end that you would land from call landing throttle back and lower full flap,

push nose down to the vertical and round out into a landing,

quite often some throttle is needed to be added,

The best thing is to go up high and play,,,,,,re visit your stall testing of your plane

I do use servo slow but possibly around 2.5 seconds to full flap, I also use elevator to flap compensation.

I also prefer to set the compensation so I need a very slight bit of back pressure on the stick, it just makes it feel more positive to fly.

going to slow will end in disaster, so go high and practice

Flaps are fun

I treated my mum to a lesson in a full size high wing Cessna,I sat in the back just for the ride, the pilot had got mum on the sticks and after some time asked if she was enjoying it,,,, her reply was yes but I wish I had a cushion to sit on so I can see out the feont window ,,,,,,that’s ok said the pilot, he popped in some flap,this raised the nose and then he re trimmed the elevator, this gave a slight nose done attitude and mum could now see out the front

Denis Watkins31/05/2020 21:55:00
4450 forum posts
113 photos

Agree, practice, practice at good height down to landing speed

Then on the down wind leg, maintain power and any tendency for nose down until after the turn and runway

In front of you

PeterF31/05/2020 21:58:31
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536 forum posts
732 photos

On my 80" mosquito I lower the gear on the downwind leg as I pass level with the pilots box and then lower half flap when the gear is down, but at this stage keep 50 to 60% throttle on. I have flap to elevator mix with servo slow and half flap is OK with some speed. I make the cross wind turn and then the final turn and know I will have enough speed to not worry about dropping a wing. Once lined up, I reduce throttle and go to full flap, again as I have got the flap to elevator mix sorted really well the plane starts sinking nicely but without gaining speed. Recently I have tried going to full flap after the final turn and that goes OK but only because I have the elevator mix sorted AND I have servo slow so it takes several seconds to deploy full flaps from zero flaps. As others have said it is having confidence in your setup, especially knowing at what speed you can deploy flaps and what the effect is.

Adrian Hazeldine31/05/2020 22:14:17
23 forum posts
1 photos

thanks - I've got the servo slow and elevator compensation sorted and have been landing like this on half flap. The manual for the model (Hangar 9 P47) suggests something like 75-80 deg full flap.

So is it fair to say - lower gear and half flap on the downwind leg but only go to full flap after the final turn - whilst carefully managing the power to avoid slowing up too much?

bert baker31/05/2020 22:16:30
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1609 forum posts
331 photos

Obviously the question was where in the circuit would you start adding flap

well I think it’s a personal choice of where ever your happy with,

i wouldn't want to start the approach miles out struggling to see the plane and then be fussing with switches

I would drop them in on the back leg and turn in not to far downwind a bit higher than normal and do a few overshoots or pop it on the runway

Jon - Laser Engines31/05/2020 22:41:48
5512 forum posts
268 photos

Generally i drop the gear just after i start my downwind. Once down and locked, i drop half flap when the model is about half way down the downwind and opposite me. I then drop full flap just as i start my turn to final.

I wouldnt recommend delaying the full flap deployment as you dont want to be faffing about with the flaps when you need to be concentrated on the turn to final. It can be done after the turn, and its not wrong to do it once lined up, but if you do it early then its out of the way and you can focus on keeping everything else as you need it to be.

As for speed management use the elevator/flap mix to re trim the model for landing speed. Usually warbirds drop their noses with gear/flap down so they need up trim/mix to compensate.

Once you have that sorted you can ignore the elevators when landing and use the throttle instead. This has the additional advantage of meaning you cant tipstall as you are not swinging on the elevator stick. All you have to do is 'parachute' down using the throttle to regulate the descent. A little flare at a few ft, add some power and you are home.

If you need to go around open the throttle slowly and touch nothing. Dont pull the gear up and leave the flaps alone until you are well established on the climb out. Its like the approach where you dont need the distractions of playing with switches to get in the way of getting back into circuit. Changing the configuration of the model at that low speed and altitude can also be problematic

Trevor Crook01/06/2020 07:31:12
968 forum posts
69 photos

Lots of sound advice above. I also lower the wheels at the start of the landing circuit to check they come down, and select partial flap at the same time, where applicable. I go to full flap during the downwind leg so everything is settled before turning on to finals.

I said "where applicable" above as I've got a couple of Spitfires which I fly with the scale setup of no flap or full (80°. With large flap deflections like this, I find it makes the landing much safer as you can keep the nose down during the turn onto finals, and on final approach, with a bit of power on, and not risk a stall.

Adrian Hazeldine01/06/2020 08:06:03
23 forum posts
1 photos

When I've watched pilots at the shows landing the bigger warbirds I've noted that they do come in quite steeply and as Trevor says keeping the nose down around what seems to be a continuous banked turn across the base leg rather than two separate turns and then letting the nose come back up to level as they start to sink down on finals.

Jon - Laser Engines01/06/2020 08:26:25
5512 forum posts
268 photos
Posted by Adrian Hazeldine on 01/06/2020 08:06:03:

When I've watched pilots at the shows landing the bigger warbirds I've noted that they do come in quite steeply and as Trevor says keeping the nose down around what seems to be a continuous banked turn across the base leg rather than two separate turns and then letting the nose come back up to level as they start to sink down on finals.

I do a single sweeping turn to final. Its much easier to judge speed this way.

Long and flat approaches are a sure fire way to bin a warbird so always come in steep using the flaps to prevent acceleration.

If your H9 P47 is the 68 inch/20cc one in green or silver i have flown 3 of them and they all float in really nicely. They arent sport models, but as warbirds go they will tolerate a great deal of abuse.

Adrian Hazeldine01/06/2020 08:29:50
23 forum posts
1 photos

thanks Jon - yes it's the green razorback one. It flies well and I've always managed to land it ok even on just half flap but wanted to master using full flap with it. Some great advice on here!

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