Path: mythinc!moon!pixar!uupsi!psinntp!uunet!mcsun!ieunet!wsl!ha/home/harry/News From: ha/home/harry/News@wsl.ie Newsgroups: rec.aviation Subject: Re: Soft Field Landings Message-ID: <1992Mar18.184406.25567@wsl.ie> Date: 18 Mar 92 18:44:06 GMT References: <1992Mar12.233716.13785@craycos.com> <1992Mar16.192029.11062@ux1.cso.uiuc.edu> Sender: harry@wsl.ie (Harry Moreau) Reply-To: harry@wsl.ie (Harry Moreau) Organization: Workhorse Systems Limited, Dublin, Ireland Lines: 94 Here in Ireland we have 37 licensed airfields. Of these 21 have paved runways. 13 are grass only and 3 are mixed (depending on the active you land on grass or a paved surface). So a substantial proportion of private flying (and even some commercial ops.) is taking place off grass. Furthermore, the emerald isle is green because it rains all the time! So we are not only flying off grass, we fly off wet grass much of the time. I do most of my flying out of Trim which is approx. 1800 ft. long, grass and has lots of 40 - 50 ft. trees about 700 ft. off either end of the strip. Most of the time I fly either a Rallye 180 or a Cessna Aerobat. So here's my 2 Irish pennies worth on soft field ops:- 1. Preflight: Watch out for mud all over the plane. It's not so bad on high wing aircraft. But if you have spats, make sure the plane rolls easily when pushed and do some kind of check on the insides of the spats. Even in summer, you can get seriously clogged up with grass clippings. Low wingers get mud sprayed all over their flaps on each landing, and even on the tailplane. Mud may clog the flap tracks. Go to some trouble to clean it off. 2. Taxying: When the grass is nice and dry and short, the Rallye is no worse than it ever is - it has a freely castoring nosewheel and an enormous fin, which at the best of times makes taxying it a bit like taxying a tailwheeler. The Cessna taxys nicely. However even on nice short grass you have to go slowly or a bump could cause a prop strike. Holding the stick right back is essential *all the time*. When the grass is wet or muddy both aircraft are pigs. The Rallye is much the worse. They both slide and slither all over the place, particularly when braking and turning. Give yourself loads of space. Do all control inputs with plenty of anticipation, especially brakes. Go really slowly, but not too slowly; it's very easy, as another poster suggested, to get stuck. Often it's a good idea to have a wingman, 1920s style, to help with the corners. 3. Runup: On really wet grass or when muddy the brakes may not hold the aircraft during run up. The worst of this is that it might not happen immediately, it might start to move after a few seconds at checking power. Don't look at the engine stuff at the expense of looking outside. If it moves at all, CLOSE THE THROTTLE, the brakes are already on, stamping on them only makes things worse. 4. Takeoff: Here the standard text book stuff certainly applies. Stick well back; advance power slooowly. Depending on type, use some flaps. BTW, I don't think holding on the brakes is a good idea as you advance power - it's all too easy to skid and have a fight on your hands to get the plane going where you want it i.e. down the strip. Acceleration is imperceptable at first and is never good. If the grass is wet your abort point should be much sooner than normal. The plane which was soo hard to get moving is even more difficult to stop. If you must abort, don't brake if you can help it above 20kts. You will probably skid, and a skidding plane is even more out of control than a freewheeling one. As an aside re flaps, the POH for the Rallye describes a procedure for getting out of tiny fields, whereby you start the takeoff run without flaps and as the ASI begins to register (around 30 kts), you dangle them all (30 degrees). This effectively catapults you into the air at about 45kts you then climb at around 50 kts, until clear of obstacles. The POH really only recommends this procedure solo, but I have done it both with a passenger (our CFI who was at the time showing me how to do it) and solo. I wouldn't attempt it above 1500lbs (MTOW is 2250). 4. In the air: You have probably picked up muck and grass on the take off run. So there is more drag. Glide ratio suffers, fuel consumption is up. 5. Approach: Again the textbook stuff works. Slow and steep is how your approach should be, plenty of power. Don't expect to be able to set the throttle once, especially if the strip has trees, lakes or rivers nearby, you get lots of up, down and all sorts of drafts. In a cross wind, I find that turbulent approaches are better flown wing down rather then crabbed. The sudden shear as you drop to tree level can take you by surprise if you're flying wings level and crabbed and you have to react. I find wing down is a more continuous control input and so reaction is more an adjustment than a reaction. You will nearly always need to add power at this point. 6. Landing: Again the textbook advice of keeping power on until the flare is good. Close the throttle slowly, and go for a nearly three point (tailwheel) attitude - really haul that stick back, you want a full stall landing if the ground is soft. Our Rallye, though a trike, has a tailskid! The fact that the ground is soft, is a benefit in a way, you won't break yourself as easily in a firm arrival. For the rollout, I generally assume not that braking action is poor, but that it's non existant. Well, that's a long rambling tale, hopefully not too boring. --Harry Moreau p.s. I'm never quite sure whether any postings I send out are seen. Would some kind soul e-mail me if you see this? Thanks.