STOL landing a -4?

[Steve Sampson]

I was interested in the -4 landing thread under the 'safety' section. If you havn't seen it its here.

Lots of good advice on how to do safe landings. Steve Z's input in particular was helpful and informative. Entirely appropriate for the 'safety' section. [One curious thing there seems to be a strong preference across the thread for wheel (= high energy) landings. I am struggling with that.]

My question is what do the -4 drivers who routinely, and safely, operate out of short strips do? I am particularly thinking about approach speed and power. One new Irish owner, after just a few flights, tells me he already finds that a 62Knt final (71mph) sets him up for about a 770' landing. Van specs it at 425' at gross and 300' solo, and I have always found his numbers quite realistic.

Thanks,

 

[matt]

It's not strange that americans in general have a preferance for wheel landings: That is natural given the runways: In general the runway length and surface (Ie concrete etc) favours this.

Over in europe where GA to a larger extent is forced to use small sod/grass runways the full stall landing should be far more popular.

Personally I only do wheel landings on hard runways, and flying when flying GA in mainland europe that usually translates into almost never

 

[Russ McCutcheon]

Hi Steve,

Not sure what a short strip is to you but I use strips that are 1700 to 2000 feet often as well as some much longer, how I land depends on what I need, length of the runway and the surface. A 500? roll is possible but in my experience not practical because to get the roll very short you need to touch down as close to a stall as possible witch has the tail touching down what seems like a good 12?+ before the mains, this makes for an un gratifying ruff landing, the newer longer gear would help but I doubt they solve this phenomenon completely. On a soft field/turf I always go for a three point, on a short field a three point also with the flair beginning before the numbers and carried to the numbers with power in or near the three point attitude, on longer runways I often wheel land, especially at home where I often need to go to the end to get to the hanger any way.

I think we wheel land our tail dragger RVs often (at least I do) because getting that perfect three point attitude every time is difficult where if you plan to land on the wheels the speed and attitude is not as critical because the tail can be high=high speed or low=lower speed or any where in between and still get a smooth landing, just touch down easy and let up on the back stick pressure and your home. Because a three point in an RV is not a full stall you often touch the tail wheel ahead of the mains or the mains ahead of the tail witch equal not a perfect landing. Also I find that the best wheel landing is with one wheel at a time, this puts less strain on the U/C and is also less springy.

As for airspeed #s, these are experimental airplanes and no two are the same (well maybe some are), my airspeed reads very low so it won?t help you. You need to do what I have done and go practice landings where there is a nice threshold with no obstacles and start with a normal landing and then come slower and shallower tell you can put it on or near the numbers in a three point and use the airspeed numbers you get as a reference for your plane, once you get this down you will find you can feel what the plane is doing and manage your airspeed with very little reference to the airspeed indicator, I check it once on base and probably twice on final. For me I am happy to have a plane that can cruse near 200mph and land on 1700 feet of turf, most suitable runways are that long or longer, I haven?t had any need or opportunity to consider any thing shorter.

Russ

 

[jim]

AOA

Hi Steve,

The numbers are hard to give as each setup will be different. When I got my 6, I was having a difficult time nailing landings (I usually 3 point). Subsequently I installed an AOA device (PSS sport, now AFS I believe), and have been very pleased with it. The landings are much more consistent, and I rarely use the ASI only. I find that for landings, as well as pattern maneuvering, I rely primarily on the AOA device. FWIW! Good luck.

 

[WSBuilder]

I'm Curious Too

Steve,
FWIW, I have no RV experience yet and have the same question about short field capabilities. I used to land my C140 on sandbars in the middle of the Brazos River to go fishing. On short final I was only 5 kts above stall and on takeoff I frequently had 12" of altitude when the water started. I knew that airplane. I have about 800 feet of potential runway on my property and I hope to be able to fly (at least solo) out of there. I think the suggestion of working down to Van's numbers at a safe, comfortable airport environment is the way to safely discover your abilities.

 

[Russ McCutcheon]

800'

Hi Bill,

When using a 2000 foot runway with no obstacles, three point but not full stall and good braking surface I can get it landed and stopped in approximately half the length= about 1000? of runway for the hole landing in calm air, better with a head wind. Some -4s are lighter then mine and could be landed shorter, mine is 1061+ pounds empty. I have seen the video of Van landing his -4 with a passenger and then taking off with the passenger from his parent?s farm runway of 680? if I remember correctly. Van?s -4 was probably very low on fuel and a very light example at the time they shot that landing and the ground was dry and with no obstacles, wind was un-known and may have been favorable. So you might be able to operate from 800? but every thing has to be just right and then I thing it will cut way down on the number of flying days you get in a year, wet surface may be a no go because you may not stop on landing, wind blowing the wrong way and so on, and it would help if the surface was dead flat= no wooptedoos, and up hill would help. I think I would try a 1200? runway if I knew the conditions where right but for me not 800?. I have landed shorter doing a full stall but it is ruff and cant help the longevity of the airframe but did not seem to hurt it either, turf would help dampen the impact also. I think when you start flying your -4 and then look at your 800? you will have second thoughts, sorry but for most -4 and or there pilots 800? strips are not realistic, for some they might be.

Russ

 

[Steve Sampson]

Bill - I have tried to get this conversation going once before see but, with the exception of Smokey, we do not seem to have -4 drivers who regularly operate STOL. Smokey I know did his test flying and continued operation out of 900'. Someone asked what I meant by short, or something similar. [A 2000' runway I would percieve to be the same as 10000'. More than you will ever need.]

I have 1020' beside my home and my Supercub and the -9A is/was very happy there. Interestingly the -9A could land shorter than the S'cub. The -4 should be very similar to the -9A according to VAN's numbers, and his own operation appears to confirm that. I only use about 700', but would not be happy to use it if the other 320 was not there.

I was hoping to flush a few other -4 drivers out of the woodwork, and since I only asked the question this morning may yet do that.

Thanks for the other replies. Lets hope we get a few more.

Cheers!

 

[Russ McCutcheon]

The nice thing about the A models I have observed is that they can land full stall every day all day long without the adverse affect of the main legs being to short as the tail draggers are for good full stall landings. I have stood out at Independence OR and watched the A models routinely with ease lad shorter then the tail draggers. Kind of the same with the 150s converted to tail draggers, it hurt there short field performance because they sit to flat. With that said I would not trade for an A model and it would be interesting to hear from those landing on very short strips in any of the tail dragger RVs and what there techniques are. This is a very interesting subject and I am not an authority and had hoped for more input also but it might be week because most of us are not using ?short? strips, much less then 2000?. While 2000? may not be short I think 1500 is about the minimum length if you want to use it every flyable day, wet dry gusty possible tail wind if your strip is one way in like many are. I could on the right day land on 1000? but it only takes one trip across the roar, thought the ditch and the fence to ruin the hole thing witch is why I and most people who maybe could don?t. I probably flew 300 days last year and would hate to be limited by the runway.

Russ

 

[WSBuilder]

Older and Wiser ?

I am probably much more conservative now than when I used to fly in and out of places many pilots would not consider. I enjoyed the challenge and recognized the risk. We'll see what my limits are after I get the -4 done. But with good power management there is no reason a tail dragger shouldn't land as short or shorter than a tryc. I used to routinely land tail wheel first with no main bounce to fly closer to stall.

Steve,
You Brits make good use of ramps on your aircraft carriers to augment STOL capability. Ever consider incorporating one at the end of your strip? I set down in a soft soybean field once and didn't think I'd ever get out until I noticed a natural ramp near the fence line!
Bill

 

[gmcjetpilot]

Have you ever flown a RV?

It's not strange that americans in general have a preference for wheel landings: That is natural given the runways: In general the runway length and surface (Ie concrete etc) favours this.

Over in europe where GA to a larger extent is forced to use small sod/grass runways the full stall landing should be far more popular.

Personally I only do wheel landings on hard runways, and flying when flying GA in mainland europe that usually translates into almost never

Have you ever flown a RV?

RV's stall at such a low speed and nose up attitude you will hit the tail wheel way way before the mains. Full stall in a RV is an oxymoron. Yes you can do it but you are dropping it in. You can however land at very slow speed but still flying.

The main gears on RV's (especially 4's and 6's) are not tall enough for a true three point stall attitude. Sorry us Americans fly off of very short tuft, dirt and gravel in mountains as well as with big obstacles like +150 ft plus evergreen trees. I can take you into some mountain strips in the USA that makes your "mainland europe" turf Euro flying look like landing at Heathrow.

There are limits to runway length, but bravado about full stall landing is kind of moot. You land at your intended touch down point at min speed which in a RV is very slow you can land short.

However if you stall while still in the air with a RV, you will hit the tail wheel and than slam the mains in. A few extra mph will not make a difference in landing roll out length. It is better to be in control and at a low but controllable speed in RV's.

The nice thing about the A models I have observed is that they can land full stall every day all day long without the adverse affect of the main legs being to short as the tail draggers are for good full stall landings. I have stood out at Independence OR and watched the A models routinely with ease lad shorter then the tail draggers. Kind of the same with the 150s converted to tail draggers, it hurt there short field performance because they sit to flat. With that said I would not trade for an A model and it would be interesting to hear from those landing on very short strips in any of the tail dragger RVs and what there techniques are.

I don't disagree. Other Planes you can stall it on touch down, like a Cessna 152, but not the RV tail-wheel planes. The Trike RV's may do slightly better actually but again we are splitting hairs. In the hands of skilled pilot either will land short. RV's stall slower than a C-152 any way, so you don't NEED to stall to land in min distance. In fact it could be ugly.

With that said put an "A" model in tail low (dragging) landing position has a higher angle of attack than a Tail wheel RV in a three point. I would think the Trike does a little better, meaning it can land slower with out stalling as you observer. Again the pilot makes the difference and if you want you can stall a tail wheel RV on, but its kind of ugly, tail wheel first than mains drop on. I was taught and taught students per the FAA techniques. A short "SOFT" field is flown on not slammed or dropped on.

If you are skilled enough to hit your target touch down point within 1 or 2 mph consistently than tail wheel or trick makes no diff. Most people all over shoot touch down or have too much energy (speed) into the flair to some degree. The topic of capability is really not equip dependant. On the other hand there are risk flying at min speed, min glide path over obstacles, like if you lose power you're going into the weeds and trees.

 

[TShort]

On the other hand there are risk flying at min speed, min glide path over obstacles, like if you lose power you're going into the weeds and trees.

I have only 2 hours or so of RV time...

Are approaches flown with power in RVs (as a general rule)?

When I fly the 170 my entire approach is made power off, with the idea of using flaps / slips / airspeed to manage energy and arrive at the touchdown point at the correct altitude and airspeed. I rarely use power after mid downwind in the pattern. Good practice for when the fan really quits blowing!

Is this common practice in an RV or does it result in an unacceptably steep approach?

Thomas

 

[Kyle Boatright]

I have only 2 hours or so of RV time...

Are approaches flown with power in RVs (as a general rule)?

When I fly the 170 my entire approach is made power off, with the idea of using flaps / slips / airspeed to manage energy and arrive at the touchdown point at the correct altitude and airspeed. I rarely use power after mid downwind in the pattern. Good practice for when the fan really quits blowing!

Is this common practice in an RV or does it result in an unacceptably steep approach?

Thomas

It depends...

Personally, I fly a power off approach, beginning with pulling off all power abeam the numbers. With full flaps, the 70 knot descent is fairly steep, and sometimes I jockey the manual flaps to control the glide angle - full flaps is pretty draggy without gaining much lift compared to 1/2 flaps.

The only exception is if I'm trying to make an extremely short landing. In that case, I can land shorter with a flatter, power-on approach.

By the way, my airplane has a fixed pitch cruise prop. The airplane's glide angle at idle is much shallower than that of an airplane with a constant speed prop. I bet most of the folks flying behind constant speed props normally use a power on approach.

 

[svanarts]

I fly my 4 just the way Mike Seager taught me. Throttle to idle, and pull nose up a bit until you slow to 80 MPH, then set RPMs to 1200, flaps as needed. I've only ever done 3 point landings in the tailwheel planes I've flown. That's still all I do. I haven't found a wind yet that I can land my RV-4 3 point.

 

[Tom McCutcheon]

This is a very interesting and helpful topic. I don't disagree with anything any of you have said or observed. I would like to throw in an extra curve though and get other input on this subject.

My -4 is a bit lighter than my Son's and I have a fixed pitch prop (his is a constant speed prop). For some time I attributed these differences to my glide difference and landing distance. My son's plane seemed to come down steeper and mine seemed to float for ever and my landings were long.

Then one day I had my RPM checked with an optical electronic measurement and found it to be about 100 RPM greater than my mechanical tach indicated. I was idleing close to 900 RPM static. I adjusted my idle to about 600 RPM static which resulted in much steeper approaches and consistantly shorter and nicer landings.

As for the power on - power off methods of approaches, maybe the power on gives a more consistant touch down point. However, I was taught (drummed into my head by my instructor) to cut the power abeam the numbers on downwind and to learn to always make the numbers without adding power. Then to adjust the additional downwind to always make the numbers. Based on the results of lowering my idle RPM I have concluded that a "lost engine" power off (no windmill) will probably result in an even steeper glide and shorter distance to touchdown.

Sorry for the rambling, but I felt the need to cover the above items to make my point about regular very short field opperations (the topic - I think). So, to make consistant very short field landings, everything needs to always be just right. Adjust pattern, winds (headwind, crosswind, tailwind etc.), approach speed, one person / two person etc., idle speed (RPM) etc. IMHO too many things to always be perfect for a very short field landing (especially the kind with obsticles at each end. Not that it can't be done. However, little or no room for error. And the probability of one day some bent metal or worse. So in conclusion, practice practice practice. And, if all goes wrong, land long. Usually much better to run into the fence or something at the other end after disipating as much energy as possible than to land short before disipating that energy.

By the way, I use a higher approach speed with two in the airplane than with one (10 MPH more with two). This seems to make my landings much better without noticably lengthing the roll. I think this is because with two people on board the flair is shorter.

Tom

 

[Jetj01]

400' at 8,700 MSL???

Gents, a not so quick story:

In Feb '02 I was returning to Alamogordo, NM from a trip to San Antonio in my RV-4. I had but 19 miles to go as I was about to overfly Cloudcroft, NM, elevation aprox 10,000msl. Suddenly and with no warning, as I have since learned happens in the mountains there, the high overcast suddenly erupted with blinding snow. So much so I could not see in front of the plane, but rather only down. I immediately did a 180 to return to where I hoped was still snowless skies but to no avail. I was flying my VFR only -4 and knew I had to put it down or GET DOWNED!!! I looked down and saw nothing but pine trees and then suddenly a strip of a winding road thru a mountain pass. I wrapped over into a hard turn to lose energy/AS and dropped the flaps, slipped and WHEEL LANDED on now snow covered narrow (wing width) road. I chose to wheel land because i needed the increased vis to navigate the turn in the road and drive thru the snow markers which were two feet on each side wider than my wings span, not to mention the cattle trap crossing!

Long story shorter, got it stopped, pulled it off the road, and aprox 30 minutes later a passing hunter was surprised to find a blue RV-4 on the side of the road and gave me a ride to town where the FAA, sherriff, park service, Indian affairs, local news etc and every person in Cloudcroft was notified.

After warming up we drove back and marked off the area i landed in: 400 feet and the elevation was 8,700 feet MSL.

Four days later and with the approval of the FAA and Sheriff and anyone else who wanted to be there, and there was a crowd, I drained the tanks down to minimum fuel needed for a safe 10 minute flight and FLEW my -4 out of that same road. That is correct, 8,700 feet MSL on a curved road where we were able to mark off 600 feet with a 35 foot tree(s) at the departure end. I got on the brakes, ran it up, released and.....flew home!

The RV-4 is an amazing airplane, and while I hope no one ever has to experience for themselves something like this, it was an amazing confidence builder for me in this planes abilities. More to the point of this thread, if I am solo in an RV-4, Rocket or -8, I wheel land because I feel the elevator authority is limited to iniciate a true 'three point' landing. With a passenger I feel the three point is almost automatic. Finally with the short gear you WILL usually touch the tail first in a three point attempt while with the tall gear I feel it is more natural to get all three at the same time.

A 'full stall' three point landing will be marginally shorter but when you are talking the RV-4, it's all good and I'm still alive today because of it, and luck, and a lot of God's grace!!!!!

P.S. I have pictures!

Jj
Building RV-4 Fastback
RV-6
YAK 50

 

[garnt.piper]

Landings in -4

Hi Steve,

I land 3 point all the time, or at least try to. Yes, the TW can hit first, but on grass that is not a big deal, and the 'drop' is quite acceptable. I use a 58KT threshold speed (1.3xVs power off at gross), and my ASI installation is calibrated with negigible error at that end of the scale. When light/solo, this is too fast and it takes some time to stop flying and to pull up. Once solidly on the ground I retract the flap for better braking. I haven't measured my ground roll, so can't give exact figures. Any light tailwind or high threshold speed and the groundroll blows out though. You need to really nail the THS and this usually means dragging it in with power. I find I can't fly a standard 3? glideslope or curved base/finals unless at idle with full flap and almost full sidelip to keep the speed back at 65KIAS (180hp FP prop). A CS prop would ease this problem. I recently changed to full braided brake lines and the improvement in braking feel and confidence is immense.

You can do it!
RV-4 VH-PIO 280hrs 964lb empty

 

[Dayton Murdock]

Wheel landings

Hi Guys
Yesterday I practiced wheel landing in my 4 (for the first time) at Silver springs airport. I used the technique described Scott VanArtsdalen in the pattern ?Throttle to idle, and pull nose up a bit until you slow to 80 MPH, then set RPMs to 1200, flaps as needed.? I was over the numbers at 65 MPH; I let the mains touch with a little forward pressure on the stick the landing was complete. I repeated this procedure 5 more times with the same results. With the good visibility over the nose I was confident the landing would be acceptable. The rollout seamed to last longer then I would like. That could be that I am hesitant to get on the brakes. After flying a 85hp champ for years it is so cool !! to be at pattern altitude before the end of the runway.

 

[John_RV4]

Use the brakes....

Dayton,
When I checked out in my -4, the instructor insisted on hard braking on every touchdown. He also insisted on full stop landings during training.
His reasoning is this:

Many groundloops occur after touchdown but before taxi speed. This is the time when you are most vulnerable to losing it. By getting the tail pinned quickly and applying brakes, you minimize this time. Oh and it doesn't hurt your ground roll either .

FWIW.

John

 

[WSBuilder]

Mo Gas

I adjusted my idle to about 600 RPM static which resulted in much steeper approaches and consistantly shorter and nicer landings. TM

Tom - Do you run avgas or mo? Ground roll will obviously be shorter with a lower idle rpm, but in Texas summers 600 rpm on car gas results in a stalled engine if you need to go around.
Bill

 

[smokyray]

How slow can you go...

Hi Steve,

I regulary operate my RV4 out of a 900' one-way strip at a friends house.My home strip is 1900' with trees at both ends. I still visit the 900' strip both in my RV4 and my Harmon Rocket. The technique I use in my 170HP FP RV4 is the same every time. First things first, go to altitude (2.5K agl minimum) and stall your airplane with power on and full flaps. Look at the airspeed indicator and feel the symptoms of the impending stall in your butt and commit it to memory. Now just before the stall, add a bit of power and practice slow flight at 60 mph indicated and full flaps. The RV4 flies great at this speed and is very maneuverable. Practice holding altitude in 30 degree banks turns with an occasional "pull to the tickle" of inpending stall to see what your RV4's limits and indications are. Now you're ready to practice STOL.

I fly an overhead approach to every strip I can to get the lay of the land and check for obstacles, critters and strip conditon. (and wake the neighbors!) I slow my RV4 down to 70 mph indicated at full flaps on downwind but the ASI is irrelevant at this point, the sink rate, tickle on the tail and trim position tells me alot more. I turn base to final in one continuous descending turn slowing to FAS. I strive to see just under 70 mph indicated (63 knots gs gps) rolling out on final in my airplane. In proper STOL landing attitude/airspeed you will have to waggle the rudders to see straight ahead. Now it's aimpoint, airspeed, power right down to the ground. Power controls your rate of descent nicely. With a FP prop, tiny corrections go a long way. My goal is to be power-on, tail-low at 57 knots GS just above my planned touchdown point. I pull power to idle, transition to full aft stick and usually touch tailwheel first. Long-gear RV4's roll on in 3 point nicely. I prefer wheels landings with a tail-low attitude unless it's very rough, where I use three-point. Add brakes, retract flaps and I can normally turn off at mid field on my 900' strip.I have landed the Bandit at the same approach speeds in Idaho at 6000' msl with no problems. Add 5 knots for a passenger and baggage. STOL operations are one of the big reasons why I built my RV4. Both my strips are fairly rough and my biggest limfac hasn't been with the RV4's STOL capabilities but with wheelpants, gear leg fairings and brackets failing or getting really banged up in the divots, soft sand and rocks. Now I use a set of original pants with lots of extra glass and carbon fiber layed up inside them and aluminum leg fairings. Big improvement. My desire when I built the Bandit was a 180MPH Super Cub, I think I have it!

If I can land on a 900' strip every day, you can too, with practice...

Rob Ray


PS: Concerning Russ' earlier thread that A-model RV's have better STOL capabilities, possibly on smooth ground but not on a rough strip. I have nothing against the A models, I just would never own one. First this is an RV4 site and there are no RV4A's (Thank God), so I won't address them. I have heard the trike vs TD argument before. I have quite a bit of C-182A time in the backcountry and I can follow just about any C-180 anywhere, until the ground gets really rough. I have some outstanding missionary pilot friends flying JAAR's C-206's and Caravans into very short strips all over the world. They still save the shortest, roughest strips for their Helio Couriers. There is a reason the Alaska Bush pilots favorite mount is the Super Cub...The biggest problem with A's or any nosewheel airplane is breaking off the nose strut in a hole or rough spot and flipping over. I have recovered 2 RV6A model flip-overs now, one on the same 900' strip. The problem occurs when someone not accustomed to short, rough runways brakes hard on a trike RV on a very soft or rough strip. The nose strut breaks off, the remaining strut end digs in and over it goes. Taildraggers could have similar issues in holes with a groundloop or flip-over, but not often. This isn't to say the A model RV's aren't good airplanes, I just like the RV4 better.

My 2 cents...
RR


[img=http://img88.imageshack.us/img88/4199/img1126zj5.th.jpg]

 

[Steve Sampson]

STOL landing my 'cub video. The -4 will be in '08.

Well I started this thread a while back, and I am still thinking about STOL landing a -4 on my strip sometime in '08, but in the meantime since the RV-4 section is quite quiet I thought perhaps a link to a video coming into my 1020' strip in my Supercub might be fun. Apologies its not directly RV content.

Please click http://www.youtube.com/watch?v=e4OVakmsmPw

You will be on final. Its 45 seconds long.

Video credits to John Stahr.