advice on landing in eastern MT prairie

[kmaxwell]

I have purchased some land in eastern Montana on which I would like to land. With no true off-field experience I'm looking for advice. The ground is long, wide and level. It has been tilled and planted in CRP type grass some years ago which is currently about 6" tall. The ground is smooth without rocks, holes or other similar hazards, but the grass tufts make for a bumpy ride in a pickup truck. My 170 has 6.00 tires. Are these tires adequate for landing in this field? If not, what size would be? Thanks in advance for any advice.

[T. C. Downey]

Go for it, that seems not the best, but not dangerous.
I'd mow it shorter if ya can

[pdb]

In Alaska, the standard is 8:50 x 6 for off field and we go up from here. The problem is that 8:00s are the largest on the TCDS and I don't believe a STC for 8:50s exists yet (supposedly on the way soon from Atlee Dodge) and a field approval may be impossible now. My guess is that 8:00s would be fine but I have no experience on them myself. Others here may have in those or smaller tires in such conditions. The general rule is that the bigger the tire, the less rolling resistance in grass, mud, and snow and they roll over bumps better as well. Smaller tires may well be just fine on a closely mown field but why take the risk when you can easily throw on some 8:00s.

If you are in that part of MT where the field elevation is around 2,500 ft, you would probably be fine with the 8:00s if you keep the field mown and have a climb prop. If the strip is long and the departure easy, you may well do just fine with a cruise prop. The higher the field elevation, the more I would want larger tires as you have less HP to climb out.

If the field shakes you up in a truck at 55, you can imagine how it's going to feel when you are bouncing along on spring steel gear. Go for the larger tires IMHO.

[Bruce Fenstermacher]

Don't know what CRP grass is. I operate on Pennsylvania wild field grass (what ever vegetation happens to grow) which I'd guess averages 6". We are using 7 x 6:00 tires which is a compromise between 6 x 6:00 and 8 x 6:00. We would land there with 6 x 6:00 without trouble but larger tires open the envelope a bit more. You probably don't want wheel pants for continual operation and you can't mount anything larger than 6 x 6:00 with wheel pants.

The 7 x 6:00 tire is generally as wide as the 8 x 6:00 but not quite as tall so there is slightly less drag in the air but a bit larger foot print to spread the load.

[blueldr]

The bigger the outside diameter of the tires, the better it will roll over the bumps and holes. Being the bootlegger that I am, I'd personally go for the 8:50s and plead ignorance if the FUZZ ever asked. If you've been flying and landing on 6:00s, get some experience on the larger sizes before you really need them.
You may find that ground handling is different with the larger size tires and brakeing, especially with single puck brakes, will definitely require considerably more effort due to the increased arm at the wheel.

[Bruce Fenstermacher]

BL is right about the larger diameter tire but that is not really a considerations for a smoother grass field where you are most concerned with the soft ground and grass. I did operate 8 x 6:00 with single puck brakes and had no issues but again he is right with the larger diameter tires, over 8:00, the braking power starts to drop off and double puck brakes are the way to go.

[jlwild]

kmaxwell,

I have landed and taken off from ranch land, during the summer, in eastern Colorado (cattle range land) and central Texas (freshly harvested wheat fields). The 6:00x6 tires worked well. However, if the grass is over 6 inches you might want to have someone let you know how tall it really is. Plus make sure the ground is not wet. Standing water or wet soil can cause you to nose over. Only issue I had was cleaning the chaff from around the gear legs and tailwheel after returning to home base. Just be sure to use your soft field technique, when the land is dry and grass short, and you will have no problem.

[W.J.Langholz]

Mawell

Depending on the type of grass planted, the "bunch" grass, Big Blue,Little Blue, and Indian Grass over time can get a fairly large root ball that is raised 3-4 inches and can get rather ruff. Good new is this would be a prefect time of year to do some inner seeding and land rolling.
Stop down to the local NRCS and get a drought tolerant hybrid grass to inter-seed, I would also mow it short as possible, then get one of your neighbors with a land roller to go up and down it several times. I have my neighbor come a hit mine every spring whenthe ground is softer, helps smooth it out, his is 60' wide when unfolded. I pay him a little beer money and grill him a steak for supper we are both happy
The inner seeding took me several years using a finner bladed grass but it sure is great now, it was also "CRP-pasture" grass. I had a "57" 172 with stock tires on and did o.k. but it sure rattled alot and was noisy now it is great. I still let the cows graze it mid to late fall, just got to watch out for the pies

Good Luck and congrats, you will love having your own strip

[GAHorn]

... I'd ... plead ignorance if the FUZZ ever asked. ....

What would you plead if it's the insurance company that's asking? (Lessee, now... landing off-airport, with illegal tires...hmmmnnn)
Landing off-airport is the lesser problem in such a case, I believe.

[kmaxwell]

Thanks to all those who have offered advice. I recognize that 6.00 tires are probably marginal, 8.50 would be much better (but are not legal) and so 8.00 may be the best compromise, especially since most of my activity will still be hard surface.
WJ, thanks for the advise on inner seeding and rolling. You describe my field situation with grass clumps, so I'll try rolling and seeding and then see how it goes with 8.00 tires.


KM

[blueldr]

George,
Your question beats me. I always went naked as far as insurance went, except for liabilty.

[flat country pilot]

Don't know what CRP grass is.

Conservation Reserve Program. The tax payers paid us farmers to idle marginal or highly erodible land. The program started about in the early eighties and the payments have not kept up with inflation. Therefore most of the CRP land in our area is going back into production. I believe the minimum contracts were for 10 years and most of the CRP ground has been into grass for 20 or 30 years.

My experience with CRP ground is that its rough, real rough for anything driving more than 5 mph. I don't even like my farm equipment in it let alone my air plane. It is most likely full of badger holes, dirt mounds, pocket gopher holes, etc. Without looking at yours, I will speculate that you should do some leveling. You have a great opportunity and I think a nice airstrip in the middle of a CRP field will be fun.

I would spend some time walking around in it, decide your best location for your airstrip. Kill the vegetation where you want the strip to be, work it smooth, and seed new grass. Do it right away this summer and make it nice.

I put 8.50s on my 170B two years ago with field approval. If your interested I'll put you in contact with my mechanic. I fly off grass and/or stubble 90% of the time. 8.00s are enough, even for stubble fields in ND.

I don't believe AK Bushwheels are enough for CRP. Drive across it with a pickup at 30MPH and check it out. Good luck.

kmaxwell, I'm at Turtle Lake, half way between Bismarck and Minot. Where are you located?

Bill

[kmaxwell]

Bill,

Thanks for the reply.

By CRP grass, I meant a clump type grass, not turf. I agree, most CRP is pretty rough. My field has been leveled and planted in what I think is crested wheat grass. I have walked and ridden the field. It's actually pretty smooth compared to CRP or prairie, comparable to a wheat field. It's free of gopher and badger holes-at least none that I have found yet. I can drive at 40 mph in my F350 but that speed is jarring. In a SxS utv that speed is much more tolerable.

Surprised you got field approval for 8.50s. When I was in Williston some years ago, it was a pain to get the FSDO to just authorize strobes. I'm near Glendive, MT now.
Using this field would allow me to commute to work, which won't necessarily save time or money, but would be a lot more fun.

Are you seeing Bakken activity where you are, or are you outside that environment? Glad we got out of Williston before that hit.

[flat country pilot]

I don't know how to handle a clumping grass. It may be difficult to turn that into sod without killing it and reseeding. In clumps, not mounds, maybe bush wheels run at a lower psi would help. I usually keep the 8.50s at 19psi and have run them down to 16psi. They are noticeably smoother than the 7.00s I had before. But, I try to be real conservative with the 170 landing gear when landing off airport, it may be tougher than I think but I don't need to find its limit.

A few years ago Richard Cranium was the director at the Fargo FSDO. We tried for the field approval and a couple of the requirements were unreasonable. He left, a few months went by, and it went right through.

I am about 60 miles SE of the Bakken. Sure would like the $$$$ but not the headaches. There are plenty of Jed Clampett stories up there, but a lot of life styles ruined. It's no place to try and farm.

Bill

[W.J.Langholz]

Maxwell

The warm weather has melted most of the snow on my runway so I will try to get some pictures for you. You will see side by side the difference.
Do a little research on smooth bladed grasses that shoot out lots of Rhizomes. It will fill in rather quickly. A blend of Kentucky Blues, the best would be "quack" grass but check the laws, it is illegal to plant that in Minnesota. I chose not to tear my up and went the route of inner seeding 3 years in a row and roll it every year. To each his own I guess. I'm sure each situation is different.
One thing to remember is "not to fertilize" the bunch grasses really respond to N and will crowd out the spreading grass ......and you will be mowing it 2 X's a week oh well live and learn eh

I'll post some pictures later. I'm happy the way it turned out and I could use it right away.



W.