Frustrations of a Grass Runway...
Joined: Sep 2003
Posts: 187
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From: NW England
What is the drawback of digging a ditch, say 1ft deep, either side of the runway, and having a pump pumping the water out of the ditch to some location say 100m away?
Regarding reinforcement, the place where this is really needed is in the taxiing areas and the part of the runway where one moves slowly. Most planes can get their nosewheel off the ground pretty fast - in the TB20 I can have the nosewheel off after about 100m, even if it needs another 500m after that before one can climb away.
Regarding reinforcement, the place where this is really needed is in the taxiing areas and the part of the runway where one moves slowly. Most planes can get their nosewheel off the ground pretty fast - in the TB20 I can have the nosewheel off after about 100m, even if it needs another 500m after that before one can climb away.
Thread Starter
Chocks Away!
Joined: Aug 2006
Posts: 260
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From: Manchester Barton
Right, I have a quote back. £4,000 +VAT for a 620 ft by 32 ft runway. It's been stressed to me that this does not include fitting (but it was worth asking...)
That comes on a total of 40 rolls (25m length by 2m wide). So this means we're talking 5 rolls wide, with eight sets of rolls down the length of the runway.
For more details:
Sarah Davies
McArthur Group
01772 556042
(This contact is based in Preston, but they have branches around the country)
T.
That comes on a total of 40 rolls (25m length by 2m wide). So this means we're talking 5 rolls wide, with eight sets of rolls down the length of the runway.
For more details:
Sarah Davies
McArthur Group
01772 556042
(This contact is based in Preston, but they have branches around the country)
T.
Last edited by tiggermoth; 19th December 2006 at 18:00. Reason: (I hadn't put the +VAT bit on)
Thread Starter
Chocks Away!
Joined: Aug 2006
Posts: 260
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From: Manchester Barton
I have recently done the same (enquired about re-inforcement).
£58,500
Unless my maths ae incorrect this is based on £195 per 20x2m roll.
I'm sure a 20% discount could be negotiated which would make it a far more acceptable £46,800.....
It would be cheaper to put a lake in and buy a Maule with floats
£58,500
Unless my maths ae incorrect this is based on £195 per 20x2m roll.
I'm sure a 20% discount could be negotiated which would make it a far more acceptable £46,800.....
It would be cheaper to put a lake in and buy a Maule with floats
Both figures are in the same order of magnitude, I can only assume that McArthur has quoted us on the bulk order amount.
Joined: Jul 2004
Posts: 100
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From: Surrey
Just picked up on this thread. IO540 is quite right that lifting the nose wheel early in 'sticky' conditions reduces wheel drag. This is not only by not ploughing a furrow through the mire with the nose wheel, but even early in the run, some lift will be obtained from the increased AoA, reducing the drag of the mains.
I learnt on a grass strip in a C150, and on my 4th or 5th solo take off, it got to about 30kts, when it would go no faster ploughing through the mud. Feeling that I could drive it like that to end of the strip, instinct caused me to jerk the stick back momentarily, which lifted me an inch or so to be aquaplaning on top of the mud, when I then accelerated normally to lift off.
A word of warning. Even on a hard runway, lifting the nose early also increases drag from the increased AoA and angled fuselage, so acceleration will be slower, and take off run greater. As IO says, this can be much better than the even more reduced acceleration caused by ploughing through mud.
However risks are that you will get off early in ground effect, without enough power to go anywhere whilst on the back side of the drag curve (not much likelihood in a TB20!), or the oncoming hedge at the end causes you to pull back even further, which prevents you getting airborne at all. AAIB reports have both of these cases. Several years ago, an aircraft trying to depart Bodmin lifted its nose early, finished up scraping its tail on the ground, failing to get off as it went into the hedge.
Muddy strips almost preclude confidence in take off run calculations, especially as its going to be different at various point along the strip.
MikeJ
I learnt on a grass strip in a C150, and on my 4th or 5th solo take off, it got to about 30kts, when it would go no faster ploughing through the mud. Feeling that I could drive it like that to end of the strip, instinct caused me to jerk the stick back momentarily, which lifted me an inch or so to be aquaplaning on top of the mud, when I then accelerated normally to lift off.
A word of warning. Even on a hard runway, lifting the nose early also increases drag from the increased AoA and angled fuselage, so acceleration will be slower, and take off run greater. As IO says, this can be much better than the even more reduced acceleration caused by ploughing through mud.
However risks are that you will get off early in ground effect, without enough power to go anywhere whilst on the back side of the drag curve (not much likelihood in a TB20!), or the oncoming hedge at the end causes you to pull back even further, which prevents you getting airborne at all. AAIB reports have both of these cases. Several years ago, an aircraft trying to depart Bodmin lifted its nose early, finished up scraping its tail on the ground, failing to get off as it went into the hedge.
Muddy strips almost preclude confidence in take off run calculations, especially as its going to be different at various point along the strip.
MikeJ
Joined: Jun 2003
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From: EuroGA.org
Yes, I think there is a lot of misconceptions going around takeoff techniques and how they relate to the figures in the POH.
The POH figure is for a dry hard runway, unless otherwise stated.
A "soft field" takeoff is going to use a lot more runway than the hard runway figure. Even doing a soft field takeoff on a hard runway (pointless except when doing an FAA checkride perhaps) will use a lot more runway because of the extra elevator drag, acting like a giant air brake.
I suppose that in a low powered type (e.g. a C150) a soft field takeoff may be the only way to get off the ground so one cannot even do a comparison with a normal takeoff off the same muddy grass, but the resulting takeoff run is going to bear little resemblance to what is in the POH
I did a soft field takeoff the other day in the TB20, off a hard runway, and the run, including the bit in the ground effect, was about 600m. Whereas a normal takeoff is about 350m, both cases about 10% below MTOW. It was staggering how much extra drag there is due to the elevator being all the way back. A soft field takeoff may keep the mud collection down but that's not much use if you don't get off the runway. And this is a TB20 which has loads of power.
Those flyers that get handed out about grass taking 30% more than tarmac, etc, are meaningless in so many cases, IMHO.
The POH figure is for a dry hard runway, unless otherwise stated.
A "soft field" takeoff is going to use a lot more runway than the hard runway figure. Even doing a soft field takeoff on a hard runway (pointless except when doing an FAA checkride perhaps) will use a lot more runway because of the extra elevator drag, acting like a giant air brake.
I suppose that in a low powered type (e.g. a C150) a soft field takeoff may be the only way to get off the ground so one cannot even do a comparison with a normal takeoff off the same muddy grass, but the resulting takeoff run is going to bear little resemblance to what is in the POH
I did a soft field takeoff the other day in the TB20, off a hard runway, and the run, including the bit in the ground effect, was about 600m. Whereas a normal takeoff is about 350m, both cases about 10% below MTOW. It was staggering how much extra drag there is due to the elevator being all the way back. A soft field takeoff may keep the mud collection down but that's not much use if you don't get off the runway. And this is a TB20 which has loads of power.
Those flyers that get handed out about grass taking 30% more than tarmac, etc, are meaningless in so many cases, IMHO.
Joined: Sep 2001
Aviation Qualifications: CPL
Posts: 2,787
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From: Toronto
I once had the occasion to take 4 people up in a C-172 from a sand strip. First had a talk with the local CFI/operator to see if this was at all possible. His advice was not to keep the wheel all the way back once rolling.
Taxi took considerable power. Picked a point where I would abort if not airborne -- in the sand, 100 yards was plenty
Full power, wheel all the way back got me to about 40 kt and no more; so, eased off on the wheel. The a/c accelerated and I lifted off, built speed in ground effect and climbed away
The trick is to keep the nose wheel just clear of the ground once you have 30 kt or so as you now have lift taking the load off the mains.
Blasting all the way down a soft runway with the wheel/stick all the way back can add you to the statistics as before mentioned
Taxi took considerable power. Picked a point where I would abort if not airborne -- in the sand, 100 yards was plenty
Full power, wheel all the way back got me to about 40 kt and no more; so, eased off on the wheel. The a/c accelerated and I lifted off, built speed in ground effect and climbed away
The trick is to keep the nose wheel just clear of the ground once you have 30 kt or so as you now have lift taking the load off the mains.
Blasting all the way down a soft runway with the wheel/stick all the way back can add you to the statistics as before mentioned
Joined: Oct 2006
Posts: 55
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From: Beechy Bucks
Our home airfield stayed drained and perfectly servicable.
but....
CAVOK this morning - only on this side of the Chilterns.
Freezing fog on t'other side of the hills, all the way across Oxfordshire it seems.
Grounded. Grrrrrr!
but....
CAVOK this morning - only on this side of the Chilterns.
Freezing fog on t'other side of the hills, all the way across Oxfordshire it seems.
Grounded. Grrrrrr!
Joined: Jun 2001
Posts: 185
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From: Morton-in-Marsh
Shortstripper - haven't seen a response to your query, but it seems to me that iff Goodwood has an A/G service, it is you who are in charge, and you can, theoretically, do what you want. They might not invite you back if you do something silly, but taking off half way down a runway in a STOL aircraft wouldn't really constitute that.
If it is AFIS, they have the power to give instructions to ground movements (I think), but if you say you are lining up for take-off and then take off, you can do it, because they have no authority to grant you approval for take-off or refuse it.
Why not have a word with the aerodrome manager? They are probably concerned about noise, and you might be able to discuss the whole thing and reach a common sense answer (although in my experience, common sense is not common at airports!)
If it is AFIS, they have the power to give instructions to ground movements (I think), but if you say you are lining up for take-off and then take off, you can do it, because they have no authority to grant you approval for take-off or refuse it.
Why not have a word with the aerodrome manager? They are probably concerned about noise, and you might be able to discuss the whole thing and reach a common sense answer (although in my experience, common sense is not common at airports!)
Joined: Sep 2003
Posts: 187
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From: NW England
What a fantastic 'solution' - and even if it in't - what a great idea anyway.
Just heard that one of the guys at a local Club that is notorious for getting claggy and saturated has invested in a racing hovercraft which he bombs up and down the runway when it is completely sodden:
1) It's great fun
2) It doesn't damage the surface
3) Allegedly it dries the surface out
Ebay - here I come............................................
Just heard that one of the guys at a local Club that is notorious for getting claggy and saturated has invested in a racing hovercraft which he bombs up and down the runway when it is completely sodden:
1) It's great fun
2) It doesn't damage the surface
3) Allegedly it dries the surface out
Ebay - here I come............................................
Joined: Aug 2001
Posts: 215
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From: Hampshire, UK
Shortstripper wrote:
Hi SS. I was intrigued by this as I have seen occasional mid-point departures, including a friend visiting in a Rans S6 who was not keen to taxi downwind to the hold in a 20 knot breeze. Also the FISOs at Gwd are an excellent bunch, always helpful, and always friendly!
So, I spoke with the FISO yesterday, and he recalled the occasion immediately .... it seems that on that particular day it was felt that the threshold was actually preferable being less wet than the area where you suggested departing from; apparently there is a tendency to standing water near the runway intersection. Agree or not, that was the reason, and with the best of intentions.
Regards
Slip
I flew into Goodwood Saturday and whilst they do a pretty good job of keeping their runways going, I can't understand the inflexibility shown? As I was taxiing to take off, I called up and offered to pull onto the runway where I was (half way between the tower and the hold) to save the grass at the threshold. There was one other on downwind in the circuit and I stated I was STOL ... but no I was told to taxy to the hold as usual and take off from the bit of grass that is getting increasingly muddy.
So, I spoke with the FISO yesterday, and he recalled the occasion immediately .... it seems that on that particular day it was felt that the threshold was actually preferable being less wet than the area where you suggested departing from; apparently there is a tendency to standing water near the runway intersection. Agree or not, that was the reason, and with the best of intentions.
Regards
Slip
Joined: Dec 2002
Posts: 374
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From: Hellfire Corner
"I spoke with the FISO yesterday, and he recalled the occasion immediately .... it seems that on that particular day it was felt that the threshold was actually preferable being less wet than the area where you suggested departing from; apparently there is a tendency to standing water near the runway intersection. Agree or not, that was the reason, and with the best of intentions."
Slip, reassure me you were merely talking to the FISO and not airing that wonderful machine?
This isn't thread drift because in this wind, one doesn't need a runway...
Slip, reassure me you were merely talking to the FISO and not airing that wonderful machine?
This isn't thread drift because in this wind, one doesn't need a runway...
niknak
Joined: Dec 2001
Posts: 2,335
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From: UK
We recently had to withdraw our (tarmac)cross runway due to significant subsidence which would not have been cost effective to re instate.
However, I am convinced that the land adjacent to it is more than capable of supporting a 800 to 1000m grass runway.
I am aware of the CAA (CAP168) requirements, but any support for this from operators and how I could present this as a low cost alternative for G/A at our place would be gratefully recieved.
Ta.
niknak.
However, I am convinced that the land adjacent to it is more than capable of supporting a 800 to 1000m grass runway.
I am aware of the CAA (CAP168) requirements, but any support for this from operators and how I could present this as a low cost alternative for G/A at our place would be gratefully recieved.
Ta.
niknak.
Joined: Aug 2001
Posts: 215
Likes: 0
From: Hampshire, UK
ChampChump wrote:
Indeed I was merely talking to the FISO! I was all set to meet with others at Henstridge, but the cloudbase at Gwd was around <500' all day. I hung around to see if a short local might be on, but sadly not. That's it for 2006 it would seem.
Back to the thread ... maybe the threshold is in any case the best place to start from on a muddy runway, especially in a stol aeroplane, as most touchdowns (thumpdowns?) which damage the surface are much further down the runway!
Slip
Slip, reassure me you were merely talking to the FISO and not airing that wonderful machine?
Back to the thread ... maybe the threshold is in any case the best place to start from on a muddy runway, especially in a stol aeroplane, as most touchdowns (thumpdowns?) which damage the surface are much further down the runway!
Slip
Joined: Apr 2000
Posts: 2,333
Likes: 1
From: gone surfin'
Aha the Northern Clay- just digging in some horse manure in my quagmire just as we speak.
I seem to think Bartons strips overly a massive bed of cinders, so I guess things could be a lot worse.
In my experience, things start to drastically improve as soon as the shoots of spring appear.
I seem to think Bartons strips overly a massive bed of cinders, so I guess things could be a lot worse.
In my experience, things start to drastically improve as soon as the shoots of spring appear.
