do you like it hard or soft.........

[sexybeets]

the runway that is ;)

Having completed my entire PPL on hard surfaces, (from 2500ft to 12,000ft :eek: ), what are the main differences I'm likely to encounter on my first grass strip flight?
I seem to remember reading that take off runs can be longer/landing runs shorter or is it vice versa? Obviously grass length, and wet or dry are other factors.

Any knowledge to share? :)

[formationfoto]

You have it about right. There is additional roll resistance on grass which will shortern landing and lengthen take off particularly if the grass is longer than bowling green cut. Other things to look out for are lengthier landing runs on wet grass if normal procedure is to brake hard. Wet grass can make a great skating rink. The other, and often most noticeable is that grass strips are often far less even than hard runways and you can expect to be shaken and stirred a little.

Not a grass vs hard issue but often grass strips will be shorter than hard runways, also ofetn less well marked so this can create very different perspectives than (say) a hard runway at an international airport.

I would only advise avoidance in the case of an aircraft with take off and landing performance which is marginal on the length of runway in question or the aircraft has limited prop clearance. Otherwise caution is adequate.

[foxmoth]

The thing I remember most from my first grass ops was the NOISE, tarmac tends to be nice & smooth but grass bounces the gear about and makes for a much noisier run down the runway.

[QDMQDMQDM]

The thing I remember most from my first grass ops was the NOISE, tarmac tends to be nice & smooth but grass bounces the gear about and makes for a much noisier run down the runway.

Nah, that's only in spamcans, especially Cherokees, which clatter and clang like an oil drum rolling out of control down a steep mountain. ;)

QDM

[Final 3 Greens]

Try a visit to Fowlmere (EGMA) - the smoothest 700m of grass I've ever used.

IMHO when you use a strip like this and it is not waterlogged, it's the finest surface to make your arrivals feel good!

[foxmoth]

[Nah, that's only in spamcans]

As that may be what Sexy is flying, maybe relevant. If a Tiger moth with tailskid then you will notice - lack of braking (virtually nil!) & reduced directional control. Type is definitely a factor here, as the Pa28 was the first that I operated on grass the noise was the noticeable thing.

[knobbygb]

Each bumpy grass runway has it's own 'personality'. If you haven't landed on a particular strip before, be prepared to be bounced into the air at around stall speed, either on landing or takeoff. Not so much of a problem if you're expecting it, but can be on a new runway. Just keep the weight off the nosewheel as much as possible (if you have one) - the 'oildrum' sound in a Pa28 is a dead give away that you need more back pressure.

I'm learning on grass and have problems with perspective and height judgement when landing at large 'international airports'. Guess it's just down to experience.:D

[Aussie Andy]

I am always surprised when I read of people who trained on grass being a bit anxious about landing on hard surfaces. Like you, I trained on hard - but I like both (steady!)...

I was a bit taken aback with my first solo grass landing, which happened to be at Goodwood on 06 on my QXC. This runway is plenty long - at least as long as the hard surface I had departed from at my training airfield Wycombe - but was slightly damp (morning dew?) and I was very surprised at how slippery it was... this became apparent when I started braking! Easy to deal with, just backed off the brakes a bit, but made my heart skip!

Be sure to be familiar with all the relevant calculations as shown in the Saftey Sense leaflet, and even if you don't think its necessary I'd recommend that you actually do the calculations with your POH in hand - at least the first few times you use a given grass runway. You'll be surprised at how all the various fudge factors add-up! For instance, I know that if I am in our club's Dakota (heavier than a regular Warrior) then I can't accept a landing on Sywell's 15 (unless it happens to have a seriously stonking headwind!). So whenever I go there in that aircraft, I make note of this and if they can't give me another runway (if in XW limits) I go elsewhere.

I really enjoy some bumpy grass strips - e.g. White Waltham's 25 - you don't get to decide when to become airborne, the runway kinda decides for you ;)

The relevant Safety Sense leaflet 7B is here (http://www.caa.co.uk/docs/224/ssl7.pdf) and similar information is in AIC 67/2002 (Pink 36) (http://www.ais.org.uk/aes/pubs/aip/pdf/aic/4P036.PDF)

(Reading Simon W's post below has reminded me that we have grass at Wycombe! But I had never had to land on it solo before the experience mentioned at Goodwood...)

[Bluebeard2]

Did a bit of learning on both and have used a bit of both since...grass tends to flatter my landings as its usually a bit softer than hard, but you do have to be very circumspect about potential prop-strikes in tricycle aircraft , its v. important to keep the weight off the nosewheel as much as possible. Take offs, conversely, can be a bit of a random affair as small bumps and lumps can have you skipping down the runway before the aircraft is really ready to be airborne.

Grass can also be surprisingly draggy for take off and slippery for landing, take a good look at the relevant Safety Sense leaflet. I also seem to recall the Thom manuals cover this area pretty well, in particular the performance factors you need to apply.:eek:

[Simon W]

As with Aussie Andy my training airfield is also Wycombe. My first landing on a grass runway was actually when doing circuits at Wycombe when I was instructed to setup for an approach on 25L (grass) instead of 25R (hard). The main thing that shocked me was how much bumpier it is. Doing a take off it feels like the plane is going to fall apart. I think with grass strips you've just gotta be extra extra light on the nosewheel.

[bottieburp]

A lot of heavily used grass strips tend to be really rough despite efforts to smooth/ drain them.

I have landed on plenty of strips in 26 years of flying and the roughest ever - ever - is the one at Woburn. I feel that it is the ideal 'what would it be like to force land in a ploughed field' simulator.

Mind you - I did chicken out at Lundy a few years back - a bit better now I believe.

I actually prefer grass. Despite your tyres and brakes lasting longer, grass runways are preferable for old taildraggers.

Don't get the drift off quite right in a spammer and it just costs you rubber. However, in some tailwheel types it can spoil your whole day.

A groundloop on grass is usually a red face only. Do it on tarmac and the risk of damage increases.

Check out Weybourne nr. Cromer. I went there last week in the Robin. Slopes/ rising ground/ do you take a tailwind component and go downhill? All decisions that will not be necessary on tarmac. I dont know of any that aren't flat or thereabouts.

(Weybourne has an interesting tank/ Aviation museum - they also used to fire off DH Queen Bees there in the War. Nice restaurant but now closed until the spring. Strip should be OK to use though..)

All part of the learning process.

Get some in!

BB

[big.al]

I learnt on hard (6000ft) runways but now fly out of Netherthorpe with the shortest (licenced) grass runways in the UK.

Apart from being bumpy, the main difference I find is the actual take off. On a hard runway you make a (gentle but positive) rotation by pulling back on the yoke at the appropriate speed (say 55kts in a C150 without flap).

On a grass strip, common practice is to use the soft field technique, i.e. pull back slightly on the yoke to lift the nosewheel clear of the grass to reduce drag. This tends to result in the aircraft flying itself off the runway, and so care is needed to level off when clear of the grass to allow the airspeed to increase - otherwise a significant risk of stalling may occur if it is gusty.

Combine this with the bumps, and it seems as though you actually do about 10 take-offs and 9 landings in every take-off run....;)

[bluskis]

I seem to remember a technique where you jumped the flaps, that is at a speed just below normal take off you dropped two stages of flap and hauled the airplane off the ground, thus shortening the ground drag of a grass strip.

Is this still a valid technique?

[sexybeets]

Many thanks one and all, it never ceases to amaze me how much information this forum can provide :)

I think there's probably enough experience here to start an online groundschool, you should start charging fees :D

[bottieburp]

Dear Bluskis,

THere has to be some aerodynamic advantage in this, ie accelerate without the drag of the flaps and then dropping them at the critical speed. However, I suspect that it is something for experienced bush pilots in really tight strips or nutters - sounds lke a recipe for a smoking hole. I can't imagine anyone teaching it.

Maybe glider tug pilots practise this when snatching a glider out of a small field? I can understand it then perhaps.

They are generally very experienced and really current.

Bottie

[big.al]

Bottie - agree with you - sounds little like a recipe for disaster to me. I can see the principle of gaining groundspeed & airspeed more quickly, but even to drop 10 degrees of flap would suddenly create so much additional drag I'm not sure what the resultant aerodynamics would be like. Add to that any crosswind element and.....

It was certainly not something my instructors suggested to me. I would suggest that if you can't get airborne within the available TODA using the airframe recommended short-take off technique, then you're either too heavy, too high or too hot. Or you picked a bummer landing at that airfield in the first place....

[bluskis]

Bottie
Thanks for reminding me of the aerodynamic reasoning behind this technique.

I was taught it back in the 1960's and used it on Cherokees.

I wouldn't try it today without a refresher with an instructor, and that means I will probably never use it again as my SEP has lapsed leaving me just with an MEP.

[knobbygb]

Bluskis, I asked the same question of my instructor once and when she'd recovered from the shock explained:

What if when you pull the handle nothing happens?
Or the flaps come down asymetrically?
Or you miss the level and have to look down inside the a/c
Or you accidently pull the gear retract (in a retractable, obviously)

Mind you, {anorak on} it works well in FS2000 {anorak off} ;)

big.al - If I'm ever allowed to fly into Netherthorpe, I'd be very tempted by this technique! :p

PS. Or what if you're in a C150 - the flaps would just be extended by the time you turned downwind :D

[big.al]

Knobby - if you're from Derbyshire, where do you fly out of?

Quote: "Or what if you're in a C150 - the flaps would just be extended by the time you turned downwind"...

... try that at Netherthorpe and you'll be across the road and into the farm by the time the flaps are deployed, or if taking off on 06 you'll probably be on the crown-green with the bowlers at the next village, and they don't take kindly to people using their green without having booked first...:D

[bluskis]

Knobbygb
You have checked flap integrity and operation as part of preflights, so assemetric deployment is unlikely.

The flaps were mechanically operated not electrically operated, it was a low wing aircraft not a high wing aircraft

The big thing I remember in the Cherokee was to make sure you haul on two stages, not three, but it had a big handle and definate clicks as I remember, and it was fixed u/c so no confusion there.

However as I previously said it was a long time ago and I personally would want to go through the manouvre with someone current on the procedure before trying it again.

My experience of rough and unlicenced strips is such that I give them a miss.

[QDMQDMQDM]

I seem to remember a technique where you jumped the flaps, that is at a speed just below normal take off you dropped two stages of flap and hauled the airplane off the ground, thus shortening the ground drag of a grass strip.

This was discussed extensively in a thread recently. I can confirm it works a treat in a 150HP Super Cub, when popping 50 degrees of flap does indeed cause you to jump into the air. It's an extreme technique, though, and I imagine that in many aircraft you could end up with a very red face doing it.

<<Bluskis, I asked the same question of my instructor once and when she'd recovered from the shock explained:

What if when you pull the handle nothing happens?
Or the flaps come down asymetrically?
Or you miss the level and have to look down inside the a/c
Or you accidently pull the gear retract (in a retractable, obviously)>>

Or what if there's a giant tsunami and we all get drowned?

<<PS. Or what if you're in a C150 - the flaps would just be extended by the time you turned downwind >>

In the distant past I have done it in a 172, when you select the flaps down and then count three. I somehow doubt it would work in a 150. Choose the aircraft carefully.

QDM

[foxmoth]

the 150s I learnt on had manual flaps - would probably work a treat, but I would only use this in extremis.:p :rolleyes: :eek:

[distaff_beancounter]

What is being taught, for T & Gs on grass, these days?
Or does it depend on the aircraft type?

My personal preference, on the assumption that I am using full flap, on the approach is:-

PA28s, with manual flaps of the "handbrake" variety, is quickly drop the flap lever from 3/3 to 1/3, at touch down.

AA5B & GA7, all with reasonably speedy electric flaps, is select flaps up, at touch down. This probably means that the last bit of the flap, is still running up as the A/c gets airbourne again.

Given the choice, I think I prefer to gain speed without the drag, whilst sacrificing the bit of lift gained from the flaps.

[knobbygb]

distaff, I am taught not to remove any flaps until immediatley after becoming airbourne again. This is in a Pa28 with the 'handbrake' flaps you talk about.

I think the idea is to avoid, (a) the distraction of reaching for the lever, (b) avoid taking too much flaps off, and (c) just in case you pull the gear retract by mistake in a more complex type.

The procedure is to go from full flap to 20 degrees (2/3) as soon as airbourne as this last stage is nearly all drag. You can actually feel the speed build as you do so, without any noticable loss of lift.

I must admit though, that I regularly put that third stage in whilst still on the ground (but only when there's no instructor watching).

[skydriller]

This is something that I thought everyone would do basicly the same, seeing as how we all spent so much time doing touch&gos when training...

I have always been taught :

1. Flare & Touchdown, center of runway, keep straight... Im Happy..
2. Carb heat cold, Flaps up to takeoff setting, check still straight...
3. Gradually re-apply power, keep straight...
4. Check instruments & when at rotate airspeed off you go again...


I am somewhat surprised to hear that some are being taught to get back in the air with full flap, this seems dangerous... but then maybe I am mis-understanding what you are saying.

Regards, SD.

[distaff_beancounter]

skydriller My question did relate specifically to GRASS runways, as I was interested to see if pilots were being taught a different technique, compared to that used for T&Gs off tarmac.

But, by the way, as regards carb heat, I was taught to put it back to COLD, at about 400ft on finals, so that the engine is ready to give full power, in the event of a late go-around.

So, it looks as if we were (or are) not all taught the same. :)

[skydriller]

Distaff....

Learnt to fly on a hard surface in the UK, Have since moved to France and started flying Robins from a grass strip here, 900m long. The only thing that I had pointed out by my instructor is to really make sure that weight is off the nosewheel and ensure min. stage flap is always used for takeoff, not nessecary for long hard surfaces though...

BTW interesting point about the Carb heat.

Regards, SD:)

[knobbygb]

About the carb heat - I was also taught to turn it off before touchdown - perhaps at 200 ft. Last thing you need on the roll out before a go around is an extra lever to remember to move.

The problem is, "about 200ft" can be 30 or 40 seconds before power is re-applied with the engine at idle (or nearly), plenty of time for ice to build up I would have thought. I can see the point in teaching students to do things really early, but I tend to delay a bit and go to cold just a few seconds before crossing the fence (or forget completley of course :D )

I suppose the thing with the flaps depends on the aircraft really - with plenty of power, leave the flaps down. If marginal, get them at least partially up ASAP. One-up in a pa28-161, you can still get 600fpm climb with full flaps (I know, 'cos I sometimes forget to retract at all :( )

[QDMQDMQDM]

The other reason to select carb heat COLD on the approach is that with carb heat HOT the air reaching the carburettor is unfiltered, so all kinds of crap can, theoretically get in, especially on grass / gravel / dirt strips. I still remember only 50% of the time, though.

QDM

[bluskis]

'Carb heat cold' is still one of my pre takeoff checks, even though I don't have carb heat, but it has disapeared from my downwind/approach checks.

However I am pretty sure it used to be cold for the approach, as was previously said to be able to expedite a full power missed approach .

Carb icing would any way have been checked for at some stage in the circuit or flight and any indication would probably nullify approaching with it cold.

Do Continental engines differ from Lycoming on the point of carb heat application?

[distaff_beancounter]

blueskis In my experience, not only does use & effects of carb heat vary with different makes of engine, it varies with all the Lycomings in different types, in the types that I fly.

On the PA28-181 & PA28R-201(Wot Rubbish!! its fuel injected), I select carb heat on base leg & back to cold on finals, at about 200/300 ft.

The AA5B/AG5Bs seem to hate carb heat, & sound very huffy (or whatever the techie term is!) after more than a few minutes on hot, so I usually select cold before 400 ft.

The GA7s very, very rarely seem to get carb icing, & I was taught not to select carb icing on base/final at all. But, as with most twins, you tend to keep more power on base & finals, than with some singles.


Flap settings for T & Gs on grass:-

It is interesting the number of different techniques that have now been aired on this thread.

I have never tried a T & G on grass, (or on short tarmac runways)leaving more than 1/3 on the PA28s, or nil on those with the electric flaps. Except, of course, occasionally when training, when I forgot to retract any flap at all! :(

I am still chewing over the relative merits of flap settings for grass, in terms of lift & airspeed, v drag. I was taught that the aim was to get the aircraft airbourne in as short as possible run, then hold it in ground effect to build up speed.

I don't do really short grass runways (<500m) 'cos they are much too scary. :(

For those of you who do use short grass runways, what flap setting & other techniques do YOU use? :confused:

Or, I suppose you never do T & Gs, 'cos you do perfect landings at every first attempt! :D

(Edited for brain failure, before someone else spots it :D )

[RotorHorn]

Good thread. Interesting stuff.

Only one question...

...what's a runway?

:D :D :D

(I'll get me coat.....)

[FlyingForFun]

For what it's worth, I was taught one stage of flaps for take-off from hard grass in a PA28, although I can't find reference to that anywhere in the POH. However, standard short/soft field technique in the POH is 2 stages, so I can't see that 1 stage could be considered dangerous. On muddy grass (e.g. White Waltham in the winter) I use the POH soft-field technique. On a touch+go, I retract the flaps to one stage (or zero on a hard runway) after landing.

Taking off with full flaps in most types seems dangerous - it will definitely extend your take-off run compared to whatever the normal short-field technique is (usually one stage below full flaps), and there are no published figures to give you any idea how long the take-off run will be. Having said that, if this is what you've been doing since you started in the circuit, it may be more dangerous to change your habits now, especially without an instructor sat next to you...

As for the original question, in a tricycle I prefer hard runways every time. Grass is more bumpy, but not really any harder - just different. In most tail-draggers, I prefer grass every time. I tend not to look at the ASI during take-off in a tail-dragger, I rely on the responsiveness and feel of the controls to tell me when the aeroplane's ready to take-off so I can keep my head out of the cockpit. Being bounced around a bit on the grass provides a lot more clues as to what's going on. And during landing, if you've got even the slightest amount of drift or yaw when landing a tail-dragger on a hard runway, you'll know about it, and you'd better be quick on the rudders! The Europa isn't a normal tail-dragger, though - and although I still love landing it on grass, I'd rather take off from a hard runway, given the choice - the technique is much more difficult, but it's also more forgiving. (But it's not often we have the choice!)

FFF
-----------------

[Loony_Pilot]

The Continental engine on the C150 is very prone to icing, so I teach my students to leave Carb Heat Hot all the way down the approach to touchdown. The engine can ice up amazingly quickly, a matter of a few seconds and the last thing you want to be doing at 200 ft with not enough power to make the runway is having to re-apply carb heat and hope!

I accept the issues of having to go-around with less power and the fact that dirt and grit can damage the engine if you're landing on a bumpy or dusty strip somewhere, however I feel that in most cases a go-Around can be anticipated and simulataneously applying full throttle and carb heat cold in a C150 is very simple.
In the event of having to go around at the last second the C150 will happily climb awaywith carb heat hot.. and if you have been taught to always simultaneously apply carb heat cold as you apply full throttle you will have no problems with performance or the possibilty of engine failure due to a sudden rich cut.

Lastly I feel that the chances of engine icing and subsequent failure on approach are much greater and the risks therefore higher than that of a last second go around with reduced power.

For touch and Go's I teach

Flaps Up
Carb Heat Cold
Full Power

Of course, making sure you're keeping the aircraft straight and stable on the runway.

LP

[Lemoncake]

For those of you who do use short grass runways, what flap setting & other techniques do YOU use?

It really depends on a number of factors. But as a general rule in my 150, when I'm solo, I'll use an approach speed of 60 mph, and 30 degree flap, especially when it's a little boisterous. When 2-up/plenty of fuel, I'll often use 40 degree flap, especially on calmer days, and with little headwind. Strip length is 450 metres.....more of an issue in getting out, than getting in.

Loony_pilot.

Thanks for the tip....until now I've been dumping the carb heat at 200ft agl. Won't be doing that anymore!!:eek:

[Circuit Basher]

Looney Pilot - the first 20 hours or so of my training were in a C172 in Canada and I was taught to bring the carb heat out to Hot as part of downwind checks and leave it Hot for the rest of the circuit - it worked for me. For a go around, the carb heat and throttle are just see-sawed, aiming to have carb heat out whenever less than 2k rpm and vice versa.

When I returned to UK to finish off, it was a bit of a surprise when I was taught to only bring carb heat out on base leg as part of the approach config and to put it in again on finals. It was even more of a surprise when after flying for 5 years and doing a check ride for the first time at Fife, my instructor reminded me to do the CRAP checks on finals. This got a puzzled look from the left seat and he explained:

C Carb Heat Cold
R Runway Clear
A Approach Stabilised
P Permission to Land

I had honestly never been taught those (but it seems from other threads that most in the UK have been). I was also fooled by a TRPACER mnemonic!

[Who has control?]

FFF said:-

Taking off with full flaps in most types seems dangerous - it will definitely extend your take-off run compared to whatever the normal short-field technique is

The recommended short take-off procedure in the Koliber is to apply the brakes, apply full power release the brakes and lower the flaps fully . Lift the nosewheel off at 50kts and she will fly out in a remarkable short distance. Retaract the flaps gently in stages during the climb out. The technique works equally well on grass or tarmac.

distaff_beancounter

The AA5 & Koliber have the samecarb heat habits - it sounds as though its going to be sick when you apply carb heat.
The rev. counter is green arc-ed all the way from idle up to max power, so carb heat is not also necessary - just advisable. We also have a Carb Temp gauge to help.

[FlyingForFun]

Thanks, who. I'm not familiar with the Kolilber, but I did say most types!

I once took off in a PA18 with full flaps, by mistake, and didn't even notice until I was off the ground - but then the flaps on the PA18 lower the stall speed by a full 2mph, so it's not surprising that they don't add too much drag. And the Europa monowheel always takes off with full flaps - but that's because the gear is directly linked to the flaps - if you lift the flaps, the gear comes up as well! :D

Since I made that post, I've flown a PA28 with an instructor (who I believe I mentioned on another unrelated thread) who likes me, when doing touch+goes, to take off before raising the flaps from the previous landing. I'm not happy with that technique, but I have to admit that, on a nice long runway, and when I've already got plenty of speed from the previous landing, the PA28 will quite happily get off the ground with full flap, even though it's not designed to. But then you wouldn't really expect anything nasty to happen in a PA28, would you? ;)

FFF
----------------