Soft/short field operation with SR-22

OK, obviously this is not an ideal back-country aircraft.

I just came back from the McCall (Idaho) Mountain/Canyon Flying Seminar, which was tremendous fun, in my 182…a fairly decent aircraft for this sort of thing, it turns out. In a couple of months I take delivery of a SR-22.

I noticed that the SR-22 POH specifies the aircraft may be operated from ‘any’ runway surface. Not that I would take it into a rough strip, wheel pants and all…but a lot of these strips are long, grassy, not all that rough…but not exactly asphalt. I sort of wonder about the non-steerable nosewheel on takeoff…differential braking isn’t exactly ideal for keeping takeoff distance minimized.

I wonder if 22 owners could share their real-world experience. How short? How soft?

I’ve operated an SR20 into all kinds of unpaved strips without any problems. Steering is certainly not an issue. If the grass is long the wheel pants are going to cause extra drag, and if it’s wet that’s bad too. But all in all the SR20 can handle most strips. The '22 has (I think) higher tyre pressures (due to higher gross weight) so that is going to work against you on soft strips, but the extra takeoff power should help a lot.

The breaking on takeoff is minimal even without the stearable nose gear on the '22.
there is just so much air flowing over the rudder. My guess is that you will get used to cocking the airplane a few degrees to one side to compensate.

I’d be more concerned about the wheel fairings, but they are removable. The ground clearance is only about 3," which is not much more than a well trimmed lawn.

On the other hand, the Peterson 260 STOL (Is that right Kevin?) is an ideal plane for that mission. Good load, excellent short field performance, but you give up about 35kts.

Marty

Tim,

I have only been in and out of a grass strip a few times in my 22, but have had no problem with steering. As Marty noted, it does not take too much speed for the rudder to become effective.

Paul
N925PW

Clyde,

Can you comment a little more on the range of your ‘all kinds of unpaved strips’ ? Have you done all this flying with the wheel pants on? You mentioned the higher tire pressure of the SR22, but wouldn’t a bigger factor be the reduced prop clearance (only 7" at max gross)?

I’ve only landed gliders on unpaved surfaces, so I’d love to hear about what we can do with these planes.

-Curt

The Peterson 182 mod is certainly designed with such circumstances in mind, although on “rough” fields it’s advisable to leave the wheel pants home, just like with the Cirrus or any other plane.

A well maintained, reasonably dry grass field should present no problems for the SR2X. Longer or wet grass, recent rain, mud etc. will increase your takeoff distance for sure. If there’s any question about the quality of the surface, a low flyby before landing or better yet a personal walking inspection of the anticipated ground roll area before takeoff is highly advisable. Catching your nosewheel in a chuckhole on the takeoff run could sure spoil your afternoon. Do all your taxiing with the yoke full aft, get that nosewheel off the ground as soon as possible on the takeoff run, and keep it off as long as possible on landing rollout. This was probably covered in everyone’s PPL training, but it’s worth revisiting!

Since you asked, having flown 3 different 260se/stols and two different SR20s, I can compare cruise speeds and conclude that the 260se’s cruise is not significantly different from the SR20: the fast ones are 155-160 @75%, and average ones (such as my current 260se) are 150-153 @75% and 146-148 @65%. Walt Conley’s SR20 is a fast one, easily hitting 158-160, and the OurPLANE SR20 at PAO that I flew for a while this year was not–it could barely best 150 flat out at 7500 feet. I don’t know the source of the variation in the SR20, but the 1972-1980 182 airframes on which the 260se/stol is based were, shall we say, heterogeneous with regard to how “straight” the airframes were made at the factory. So, you’re right when you say that the 260se lags the SR22 by 30-35 kt in cruise.

Interesting. I fly the Ourplane 182 at PAO and am getting checked out in the SR20. I’ve been very disappointed by the SR20 performance, which, as you say, is 150 kt at best, versus 145kt or more at equivalent power setting in the 182. I had been taking this as a data point on the value of Cirrus performance claims.

John

I’ve flown my SR-22 into a number of grass strips in the UK. I
have had no problems landing into 500m strips, stopping in
<300m. On the other hand I’ve found takeoffs can be rather exciting with positive control required as the aircraft can be
a bit of a handful.

– Andrew

The SR20 prop clearance is 8" for the 3 blade (which we have) and 7" for the 2 blade. I’ve never found prop clearance to be an issue, I certainly would be worried about operating from a strip where the grass was long enough to touch the prop! The position of the nosewheel tends to ensure that the prop stays above the ground - I’ve taxied through depressions and drainage channels without problems, but the advice to walk the ground first is very sound.

As far as types of surface go, I’ve been in (and out!) of various dirt, gravel and grass strips. A good gravel strip is nearly as good as a sealed surface, but watch out for stone chips on the prop - if the surface has loose gravel, it’s best to do the runups while taxiing - i.e. check the prop governor as you start the taxi roll, check the magnetos during ing the taxi.

As far as length goes, I have a rule of thumb that I want a minimum 800m (about 2500’) of runway. The longest ground roll that I’ve measured in any sense was about 400m of short, very wet and soft grass at max gross. So my 800m rule of thumb is conservative, but fortunately here in Oz most unpaved strips are of reasonable length. If the strip was less than 800m I would be carefully checking the approaches for trees and other obstructions, checking density altitude etc. etc. Unpaved strips often have trees or powerlines at the ends.

Getting in is never a problem - I would reckon the SR20 could be landed with 150m ground roll, and it slips well so getting in over trees or powerlines is not a problem, but getting in is no good if you can’t get out!

My SR22 is based at a grass strip in the UK and it can happily land on under 500m. The POH figures for grass seem to be very conservative

John,

How is the wear and tear on the wheel pants operating off of a grass strip? Is there quite a bit of clean up after landing.

Paul

Hasn’t been a problem. The worst problem is the stone chips that accumulate on the front of the nosewheel pant, which has more to do with runups on gravel surfaces, or poorly maintained sealed runup areas.

How is the wear and tear on the wheel pants operating off of a grass strip? Is there quite a bit of clean up after landing.

No really - I cleaned them last week (first time in 100 hours) and they came up fine

I just had the max prop RPM adjusted on my SR20 at its annual (It was revving about 150 down!)

The increase in speed and efficiency is astonishing. I have no complaints (now!)

Ian

Even in my 260se, advancing the prop control from normal cruise rpm (2400) to full rpm (2625) effects a 5-6 kt airspeed gain. With the slick SR2X airframe, I imagine the delta would be greater. What were the before-and-after 75% cruise speeds in your plane?

Ian,
Cirrus sets the ‘prop RPM’ at 2600-2625 from the factory. I asked them why the publish 2700 performance figures if the plane is delivered to meet that criteria…
Anyway, i picked up 3 knots or so and hit 158 often…you can review my previous posts on this if you wish,
take care

Folks,
I’m pretty close to decide to slip on 22" or stay to the 20" ( thanks to USD vs € rate that permit me now to buy the 22" near the initial budget price I had for the 20").
Is there someone that could send me real SR20 performance in C° -20; ISA,+20,+40, climb (VS) and cruise(kts) at different altitude?

Thanks.

Hi Maurizio:

You can compare ALL the performace data of the SR20 and SR22 side by side by going to the “Documents/Other Materials” section of this website on the left hand panel of the sreen. Open that section and scroll down and you can download the entire POH for both planes. The POH in section 7 contains all the performance data.
Brian Turrisi (Italian)

Actually performance data is in section 5 of the POH. In the case of the SR20 the data is full of errors. The speeds and ranges are inconsistent with entries in other tables and the math within the same tables is also in error. For example:

Endurance at 55% power and 8000 feet shows a speed of 141 knots (the same as cruise at best power) and a GPH of 8.8 (fuel burn at best economy). If you divide the fuel remaining after climb by 8.8 you get 5 hours not 5.5. If you believe 141knots and multiply it by 5 you get 705, add 17 and you get a range of 722 not 755. These numbers were from the online POH. The POH that came with my plane (the 3000 lb. version) has different numbers (just as wrong) and comes up with a range of 775 instead of 755. Based upon my experience the actual range will be 735 (50%) but at a cruise speed of 125 knots not 140.

Thanks Arthur, this is what I need.

Maybe someone has registered “real” number and could send it to me.
I’m engaged in a complex calculation between 20 and 22.
If jobs will be good I’ll post it in the members area.
But, I understood that appx 22" POH figures are good but not at all 20’s POH figures.