Skymaster for Mexico

[Jeff Nunan]

Hi,
I'm new here and would greatly appreciate your opinions on the following subject: I frequently fly to a home I have south of San Felipe, Baja, Mexico. The dirtstrip where I land is 2700 ft. and for the most part is well compacted. Would a 337's landing gear be able to handle this or would it be better to purchase a 336? Would taxiing on the dirt airstrip present any problem to either plane?
Thanks for your consideration and time.

[Ernie Martin]

I don't think that the landing gear of a 336 is significantly different from that of a 337 in its ability to handle a dirtstrip. We have several 336 owners who participate here, so let's see if perhaps they can correct me.

Guarding against prop strikes on the rear prop is a concern, and I think that the procedure is to start the takeoff run by advancing the throttle of the rear engine first, and advancing the throttle of the front engine after you've gained some speed.

The 2700 ft length should be sufficient, even with the take-off technique mentioned above, but there's not much room for errors. I remember a landing I made on an Idaho mountain grass strip (U88) early in the morning, when the grass was still wet with dew, and I used the whole 3850 feet. This was in my first 337, when I was a rookie pilot, where the mountains on the approach path led me to a too-high approach, and where my insecurity (fear?) led me to a too-fast approach. With 2700 ft you can't make those mistakes.

Again, we have some members who fly frequently into unpaved strips and hopefully they wiil add to both the prop strike and runway length issues.

Ernie

[WebMaster]

I live on a 2,700 ' long grass strip. Both Herb and Jerry have been here, more than once. Summer, winter, it doesn't make any difference. What does make a difference is weight. I don't try to take off at max gross, ever. I generally operate with less fuel, or less people/cargo. I have not experienced any problems with my prop. Herb has had more problems with his prop, but not here. Lead with the rear, get it going, rolling at a good speed, then push in the front engine, you should have no problems.

One important question is altitude. If you are near sea-level, you will have no problems. If you are at a higher altitude, you might consider a turbo, just to improve take off performance. To get the best, consider a Skymaster with Horton Stol, and the MT 3 bladed prop. Herb has that on his, and is consistently off the ground long before I can be. The MT is smoother, and accelerates faster.

There is another person with a Skymaster who operated out of a 2000' dirt strip near Cancun, and he had no problems getting off the ground.
Taxing is simple, I leave the front at idle, and use the rear for propulsion. You will find that there is plenty of thrust using primarily the rear engine. You will also find it creates a lot of dust for those behind you. On that subject, always be careful of taking off right behind a skymaster. The 'wake turbulence' caused by the rear engine is enormous.

Oh, and if you don't currently own a Skymaster, there is one for sale on E-Bay, that has Horton Stol, and MT props. It's a '68 with dual hydraulic pumps.

[Jeff Nunan]

thank you both for the prompt and informative responses. You have helped me and given me some things to consider. Thanks again.

I fly into a 3700' grass / unimproved strip at sea level with 75' trees on all 4 sides. Never a problem landing. However, because of all of the rear prop nicks I've had to deal with over the years, I always shut down my front engine for taxi after landing. It has reduced the amount of nicks.

Regarding takeoff, I have the Horton STOL kit on my bird. However, I normally fly pretty close to gross, and during summer months when the temp is 100+ degrees, it seems like I use just about all of the 3700' to get over the trees. When I am not close to gross, I can get off the ground and up over the trees in about 2000'. It's amazing the difference a "little bit" of weight makes.

Keven
________
FIX PS3

[J.T.Grant]

Dear Sirs,
just a few thoughts on the 336 V 337 operating out of a short dirt strip.
The 336 has a gross weight of only 3900 lbs but the same power allowing for shorter takeoffs and landings based on power/weight and wing loading. The 336 maintenance manual lists the 800/6.00 main tire and the 600/6.00 nose tire as "OPTIONAL" which allows for their use without STCs etc. This will give a little more prop clearance as well as the ability to handle a rougher runway surface ( trial and error will determine a good tire pressure for your particular runway).
As one who flies off the shorter strips this is the technique I use;
Flaps are down to a point that matches full aileron deflection.
1) Rear engine to 20 inches with front at idle until the aircraft reaches approx 15 knots (use GPS if needed to guage the speed)
2) Rear engine smoothly to full power.Checkguages!
3) Once aircraft begins to accelerate at a normal rate (for this condition) smoothly apply full power to the front engine.Check guages!
4) Rotate at 55 KIAS.

The process of starting the takeoff roll on just the rear engine will help to protect the rear prop, and also stop you from trying to get airborne on only the front engine if the rear has quit for some reason.(if yours ever does this find out why and fix it)

Do all taxiing and initial takeoff run with front engine at idle or you will damage the rear prop.

Before begining the takeoff roll have a planned distance down the runway that you must reach rotation speed by, or you must abort to allow room to stop.

Flown this way my 336 with HORTON and VG's can operate out of a 1000 ft grass runway at sea level with full fuel and two people on board (approx 3600 lbs takeoff weight). The only thing to remember is that the rotation speed of 55 KIAS is significantly below the single engine best rate or angle of climb speed. If you loose an engine you will have to fly level on the remaining engine and build enough speed to climb away at single engine climb speed.
Remember on the 336 you do not have to be concerned with the drag of raising the gear, of course 337 owners can install the RT Aerospace kit and delete the rear doors which removes the drag penalty when the gear is cycled.
Just my thoughts
James T Grant
N3845U

[rick bell]

operating off a dirt strip has a few problem associated with it. mine prevents me from doing run ups. both the props just get eaten and within 50 cycles the prop may not be serviceable (my strip is almost all sand and only a few spots where there is compaction. the front get chewed up just as much as the rear prop. gonzaga, punta final and puertocitos are much better. the strip is 1900' and just like the book it's off in less than 1000' at gross (sea level is a beautiful thing).
rick
oh, thank's larry

[Skymaster337B]

May I suggest NEW MEXICO instead. Not quite as much corruption as Mexico, no need for more insurance, and some of the most spectacular scenery in the country. No beaches but plenty of lakes -- some with runways very close by.

[Jeff Nunan]

My wife and I spent some time traveling in New Mexico, and we both thought it was one of the most beautiful states in the Union.
Our house in Baja is right on the Gulf of California with a million dollar view of the coast and five islands. It was inexpensive to build and is easy to maintain. The combination of desert and sea adds up to breathtaking landscape and adventurous flying. If we ever have to leave, the Enchanted State would be our next choice.