Building Runway predicament - dogleg or steep slope

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groundflyer

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groundflyer
Hi Pilots,
I'm working on the dream of building a runway on residential property. Woods are cleared, now working to grade to 3% slope or less, but rock ledge is preventing 3% max slope. I can dogleg around the high spot or else deal with ~4% slope up over high spot, then 3% slope down rest of runway.

The runway is 2500 ft cleared tree to tree. Was hoping for 2000 ft grass strip with zero to 3% grade, but need to dogleg 5 degrees around the high spot in the middle, or else build the runway up a 4% grade, or else spend a lot of money to blast 300 ft of rock away...

Which way would you prefer to land if you were flying in to visit?

thanks!
 
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But seriously - with a 2000' foot strip, I assume you are flying a cub or some other plane that likes short strips. That short of a strip with a large bump in the middle (if I'm picturing this correctly) would give you an interesting bounce up in the middle. I'd go for building it up to a consistent 4 degree slope if blasting is too expensive to get it to a consistent 3 degrees.
 
haha right! We are projecting a 3% slope UP for first 1200 ft to top, then 4% down for next 200 feet, then level (3% down if we can fill enough). But standing at one end, you can't see the other end because there is a 300 ft long "bump" of rock in the way sloping down across the runway. Could skirt 100 feet to the side around it (dogleg). Maybe make it all grass and see what is best route later..

I'd like to land a Cessna 4 seat with STOL kit on it eventually, or else bushplane or RV6..
 
If you can land on one of the legs, then go with the dogleg. One can accelerate through the dogleg on takeoff but it would be best to land on a straight.
 
I'd find the money and be blasting, then using that material to fill. Changing up and down slopes like this sounds like a bad idea and I'm not a fan of a dogleg either.
 
Rent an excavator with a hammer on it for the weekend and beat your brains out for a couple days.
 
With your more detailed description, I’d suggest even more to get it flatter. Up, down, level, on a short strip with trees right off the runway. Toss in some soft ground from rain - eh.....

If you can’t make it flat, at least make it slope and then level.

My head hurts thinking about a dog leg.
 
Fuel oil and ammonium nitrate, cheap and effective.
 
groundflyer said:
thinking the blasting would be easier if not too cost prohibitive
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We will be only to happy to help on the blasting. Just let us know when and we will bring the beer.!!

And why is so many folks against a crooked runway.?? I think it would be very unique and make the strip more personalized.

A STOL equipped C-206 would do Ok on a strip you are describing.
 
Nice picture. I notice that if you go off the runway where you're building it up around the 2100 part you'd have a 10 foot drop. In any event suggest digging enough so that the runway is no higher that 206'. That would be about 10' from your peak.
 
What's the term? Get Bent? ;)

Seriously, either should work. Personally, I prefer straight runways - a difference of 1% grade won't be too noticeable. But it also depends on the kind of plane and your flying technique.
 
What's the rock? You might be able to bust it apart with a hoe ram. Even 3% is a pretty hefty runway slope. I'd not want to do 4.
 
Rock - you have to think about it and plan.
You just can’t take it for granite. ..........
 
Why pass up a chance to blow stuff up? Please take video of the blasting. Bonus points if beforehand you hold a beer and say "Hey y'all watch this"
 
This is not going to come off all that friendly, although I really don't mean it that way, but people should probably state whether or not they have experience landing on airstrips with slopes or doglegs in their recommendations.

I have experience with both, with slopes way over 4% and doglegs probably up to 30-45 degrees (?). I love landing and taking off on sloped runways - it's fun for both taking off and landing because of the improvement in performance - so my initial reaction would be to go with slope. But I think a flat dogleg runway is actually more useful. The reason I say this is that at 2,500', for most of the planes I assume we're talking about (C182, 206, ragwing taildraggers, etc), they can pretty much land and takeoff on one section of the dogleg anyway, which makes it a moot point assuming the dogleg is at the halfway point. Therefore, if the runway is flat, you can use it in either direction.

The problem with a sloped runway is that you can pretty much only takeoff in one direction and land in the other. That means that if there is any wind at all, one of those directions is going to be a tailwind. Depending on the circumstances of that particular runway and that particular day, this may not be an issue or it may be a huge issue, and this is why I think that in general, a flat doglegged runway is potentially more useful than a sloped runway, even though I like sloped runways better.

All that being said, if you have to chose between a sloped dogleg runway or an even steeper straight runway, go with the steeper straight runway.

Edit: I just re-read your second post and realize that we're not talking about a consistent slope in either case, we're really talking about a "hump" or bump, where it's up on one side and down on the other. I have landed some airstrips like this, where there is a major hump and at the point of the hump there is also a dogleg, so that it's turning at the top of the hump. It's really not that bad, but it's a little weird because you can't see the dogleg turn in either direction. Landing, you just want to make sure that you can slow down before the dogleg but making the turn isn't really that bad, and taking off the hump kind of acts like a jump to launch you into the air, so that's kinda fun too, but you want to be ready for it and not get launched out of ground effect if you don't have enough speed. None of this is difficult, but some things to think about. One thing I don't like is strips with multiple humps, where one hump launches you before you're really ready to fly, and you slam into the the second one on the bounce.
 
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One thing I didn't see mentioned above is what is at the ends? If there are no obstacles and you can touch down on the uphill, no problem, but if you have tall trees (or you come in a bit too fast) and you have to touch down past the hump on the downhill, you may not get down before the end of the runway. It can be quite disconcerting to flare for landing and watch the runway dropping away from you at approximately your descent angle as the fence at the end keeps getting closer...

Can ordinary people still buy ammonium nitrate?
 
Dana said:
, but if you have tall trees (or you come in a bit too fast) and you have to touch down past the hump on the downhill, you may not get down before the end of the runway. It can be quite disconcerting to flare for landing and watch the runway dropping away from you at approximately your descent angle as the fence at the end keeps getting closer..
?
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I thought you always landed uphill on a sloping runway and always took off down hill?
 
WDD said:
I thought you always landed uphill on a sloping runway and always took off down hill?
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If it's steep enough, yes, unless the wind is strong enough to offset the slope. But if the high point is in the middle and you overshoot it...
 
Bump in the middle? I’d go with straight.
 
kyleb said:
Yes, but only the 32% concentration, IIRC. Used to be 40%.
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Am I guessing correctly that that's not enough to make ANFO, thus the change?

I have a friend who used to be a blaster. He retired when insurance got to be absurd. He says that nowadays not as much blasting is done anyway, slow expansion compounds are the norm now, they crack the rock over several hours. He had some hair raising stories about jobs gone wrong, though. :eek2:
 
$30k (yikes) to blast off the hump and make the right half flat (about 206 ft elevation).

Trees both ends, but the lower trees are at 130 ft elevation plus 70 foot oaks so the tops are at 210 feet. On the high end the trees are 70 footers at 206 feet, so 276 ft MSL for the tops. Was assuming all takeoffs to the low end, landings maybe downhill if strong winds and I can consistently hit the touchdown point..

What glide angle is good estimate assuming no wind (fly over tree tops to touchdown point)? 6% glideslope? 10% ?

Y'all are invited over when its done
 
Dana said:
Am I guessing correctly that that's not enough to make ANFO, thus the change?
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I think so, but with a license, I bet you (or a contractor) could buy the 40% somewhere. Even better, roll back the calendar 50 years, and anyone could legally buy dynamite sticks and blasting caps. Good times!
 
kyleb said:
I think so, but with a license, I bet you (or a contractor) could buy the 40% somewhere. Even better, roll back the calendar 50 years, and anyone could legally buy dynamite sticks and blasting caps. Good times!
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failing-with-fireworks-13-gifs-11.gif

:D
 
kyleb said:
I think so, but with a license, I bet you (or a contractor) could buy the 40% somewhere. Even better, roll back the calendar 50 years, and anyone could legally buy dynamite sticks and blasting caps. Good times!
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Civilians aren’t buying anything explosives related without a state and federal license.

ANFO is a 1.5D blasting agent - an insensitive explosive, useless without an initiation system, except for attracting the feds by dumdum posting online.

OP needs to shop D&B (drill and blast) contractors, may be possible to get a deal in between drill moves to get pattern drilled.
 
If you dog leg it now, how difficult would it be to blast it and straighten it out in the future?

I learned to fly on a sloped runway with a hump in the middle (surrounded by 50' trees), and there were some concerns:

1) You couldn't see the other end of the runway. Paying attention and making radio calls were required.

2) "The Hop" especially for aborted takeoffs. On one flight my ASI died and I decided to abort the takeoff right before "the hop". In the right seat was a resident of the strip (and far more experienced pilot), he took the plan and took off because he was not sure the plane could be stopped on the remaining downhill portion of the strip. On another instance, a resident decided to go flying with loaded Cessna 120 on a high DA day, and decided to abort because of poor takeoff performance, the plane hit "the hop" and went airborne as he aborted the takeoff. He brought the plane down and stopped it so close to the end of the runway that he had to exit the plane and push it to turn it around because he did not have enough space to turn it around while taxiing.

3) Landing downhill required that you be on speed, because slowing down downhill, on grass takes longer than you expect.

Keep in mind that your "hop" will change your abort point, depending on speed and on the plane, you will have to abort early enough to slow down before the "hop".

All else equal, I think your slope would not be unmanageable (especially if you have clear- ish approaches), but the dogleg would be a safer option.

Related but not actually answering your question: look into a product called "Expando". If you dogleg now, and clear around the granite, you may be able to chip away at the granite as time allows for much cheaper than $30k.
 
Disclaimer: This is NOT engineering advice, just a personal recommendation using FAA design criteria as a starting point.

[+4%-(-3%)]*300 = 2100' vertical curve and the hump goes away. It's more than max FAA recommended grade change, though, and would need a lot of fill to smooth it this much.

Might be able to go to [ ] * 100 = 700' (taxiway design criteria), but it's a lot less.

I wouldn't recommend a hard break without a curve to smooth it out as much as you can. I guess the real question is, how much fill material do you have...?
 
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kyleb said:
I think so, but with a license, I bet you (or a contractor) could buy the 40% somewhere. Even better, roll back the calendar 50 years, and anyone could legally buy dynamite sticks and blasting caps. Good times!
Click to expand...

I remember those days. Rode back with a guy when he bought 6 sticks at the local hardware store to blow the roots on a large tree. Good times.
 
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