I posted a video here a while ago where I landed at LKFR RWY 26 and took off RWY 08.
I was surprised by the downhill of the runway but managed to stop with the C172 no problem. Lesson learned: Pay close attention to all the details on the VAC.
My takeoff next day was RWY 08 after I saw pilots towing gliders that way. It took way longer than used to but retracting flaps right after rotation and staying in ground effect to accelerate got me off the airport.
Even spamcans like the C172 and PA28 make about 9% at MTOM, MSL, ISA and Vy.
Touché. But it was neither MSL, nor ISA – by the look of those rozzers in their t-shirts. It often isn’t. It’s actually quite tricky to climb for long at MSL while remaining at MSL.
My observation is that much of the GA fleet doesn’t make “book” figures due to a combination of physical and human factors and that people who rely on such “book” figures to out-climb terrain risk splattering themselves and their families onto some alpine rock.
I’m often and justly accused of being risk averse and if there was a published climb rate in my airplane’s POH I would apply a generous “Jesus factor”.
Jacko wrote:
But it was neither MSL, nor ISA – by the look of those rozzers in their t-shirts. It often isn’t. It’s actually quite tricky to climb for long at MSL while remaining at MSL.
You’re right of course.
If the METAR for LKMT was representative, then the density altitude on the ground was about 2500’. In those conditions a C172R at MTOM and Vy would make an average gradient of more than 7% from 0’ AAL to 1000’ AAL, disregarding wind. The runway at LKFR has an average slope of 3%.
The reported wind at LKMT would have given a 5 kt headwind component which would have improved the climb gradient by about 0.4%.
Running something heavy uphill is painful on acceleration, you’d need an awful lot of headwind I’d think to make it favourable I’d guess.
I must stop doing this but the gradient of the PA-18-150 at Vx (45 MPH) comes in at 20% at MAUW and SL.
Seems to become a pattern with OK-registered SR20s on grass runway takeoffs…
I remember a take-off with the SR20 years ago at Uetersen EDHE. RWY 1.100 m, grass wet and not all that well cut, no wind. It wasn’t a very close call, but certainly used a lot more runway than expected. Just my wife and me on board, half fuel.. Really drove the point home that you need to get that nose wheel off the ground ASAP in the ground roll in such conditions. ILAFFT. No doubt a SR22 would have done a much better job.
Grass is always a bet on factors you cannot verify until after you have landed, and wet grass is much worse.
But presumably this pilot was familiar with the condition of the runway.
I would be wary of the comment above about getting the nose wheel up, this can help if the drag is from the wheel in the grass, but does add drag from the angle of attack on the wing.
My ‘normal’ style of flying (pa28-160) on a paved runway is to get the nose wheel up a couple of inches above the runway very early and then just hold it on the mains until it is ready to fly. I would be especially inclined to fly this way on grass (get the nose wheel up) to be gentle to the nose gear, but…. I have had problems with this technique on a couple of occasions.
I have several times been unable to accelerate on grass using the nose-wheel up technique… the added drag of the wing was just too much. I can’t recall the numbers before I aborted, but I might have been able to get to 45 knots (needing say 50 or more to take off) before realising the end of the runway was coming up fast. Thankfully the grass runways where this occurred were long, so plenty of time to make a decision to stop and try again. Subsequent take off attempts which started by accelerating from the taxiway and keeping a neutral elevator achieved take offs in very normal distances with no unusual lack of acceleration.
The moral of the story is I would be reluctant to push a short grass runway with a heavy and possibly underpowered aircraft until you really know how it performs. Also be wary of the added distance when the nose wheel is up early…
Of course a more powerful aircraft will just fly off sooner with the nose up, but this is really dependant on what you have, e.g. a 180 hp super cub vs a heavily loaded tourer.
Canuck I fully agree with you. When I say ‘nosewheel off the ground’ I should have said ‘just barely off the ground’. It means pulling seriously in the beginning, but once you feel the wheel is free, let go a little.
