Rellihan
10-20-2005, 12:37 PM
To all the other good comments, I will add the following. Those having
direct experience with any of these factors are welcome to speak up. With
Gaston's coming up, this should make a good Forum on BAC, even though there
is a large "body of evidence" already there.
Landing roll-outs will be much shorter than paved-field roll-outs. They
also give you an early clue about added takeoff rolling resistance.
Even smooth grass fields are rougher on the airframe than is pavement. Make
sure your landing gear cushion disks (donuts) are reasonably "fresh" (not
all flattened out with the rubber extruding well past the metal spacers,
with vertical cracks in the OD). This includes the nose gear. The
difference in cushioning, and in landing impacts (and taxi/departure
impacts), both grass and paved, is night and day. Ask someone who recently
replaced their donuts.
Keep approach speeds low. Most of these turf fields are much shorter than
you are accustomed to. While you need to make soft landings rather than
"carrier plunks", you can't afford to float forever with partial power still
on (as so many seem to do on paved runways).
Remember that brakes will be nearly ineffective on turf at any significant
speed; the wheels will just lock up. Be prepared to do a deliberate
low-speed ground loop, with braking on one side assisted with rudder, to
avoid going straight into any departure-end obstacles. Most low-speed
ground loops are non-events in planes like ours, but few people mentally
prepare to do them deliberately. At low speeds they are pretty effective at
dissipating energy without damage. I DO NOT advocate any deliberate
practice, for obvious reasons! They can also help on pavement, but the
added tire grip makes them much riskier on paved surfaces (tipping, wingtip
contact, quartering tip-up or nose-over with prop strike, etc.). At slow
speeds I would still choose to attempt one on pavement, if it might keep me
out of certain contact with hard obstacles or a ditch ( or from going over a
cliff?!).
Hold enough takeoff back pressure to relieve the nosewheel load, but not
enough to raise it clear. On firm turf (which is all you should be using),
that will provide the best compromise between added acceleration drag and
reduced impact loads on the nose structure.
Use at least one notch of takeoff flaps for much the same reasons. If you
are comfortable with it, adding a second notch will pop you off the ground
earlier, when you get fast enough. The speed varies with aircraft, loading,
weight, power, etc., but usually is pretty close to the published stall
speed.
Climb at Vx rather than Vy; with two notches of flaps, the charts often
suggest climb speeds below Vx. Leave on one notch of flaps (or both notches
if you used two) until you approach Vy. By Vy flaps are generating more
drag than lift, but I rarely retract flaps until I am clear of obstacles,
except at large paved fields. Our planes tend to make a small nose-dip on
flap retraction, until you have begun to subconsciously correct for it.
Read the performance charts on BAC for these operations at the lower end of
the performance envelope. There is a ton of good info there. Could save
your bacon and airplane some day.
Practice these methods on pavement. Once you are comfortable with your
departure technique, and are doing it well, you can play it safe and add
maybe 20% to the "departure distance for obstacle clearance" that you are
achieving. It is a virtual certainty that you will find that number to be
well within your capability on a 2,100 foot strip.
BEWARE OF TALL GRASS! It is like operating in glue, especially when wet
with dew or recent rain. If a field is not being mowed frequently, or there
seems to be a likelihood of minimal field maintenance, look elsewhere.
And finally, check your insurance policy. Some still exclude operations on
unpaved fields.
_____
From: musketeermail@yahoogroups.com [mailto:musketeermail@yahoogroups.com]
On Behalf Of ke4oh
Sent: Thursday, October 20, 2005 9:57 AM
To: musketeermail@yahoogroups.com
Subject: [musketeermail] Grass Field Operations
Does anyone have experience operating one of our birds regularly from a
grass field? The FBO situation at my current (paved) field is beginning
to be a real headache.
There are two decent grass fields near me (one 2100 ft, the other 2400
ft) that I'm considering moving to. Both are relatively smooth and are
well taken care of.
So, what is the real-world experience with a steady diet of turf
runways? Is this a realistic possibility? Will I have any long-term
maintenance issues due to our stiff landing gear?
Best regards,
Steve Robertson
N4732J 1967 Super III
_____
_______________________________________________
BAC-Mail mailing list
BAC-Mail@beechaeroclub.org
http://www.beechaeroclub.org/mailman/listinfo/bac-mail
direct experience with any of these factors are welcome to speak up. With
Gaston's coming up, this should make a good Forum on BAC, even though there
is a large "body of evidence" already there.
Landing roll-outs will be much shorter than paved-field roll-outs. They
also give you an early clue about added takeoff rolling resistance.
Even smooth grass fields are rougher on the airframe than is pavement. Make
sure your landing gear cushion disks (donuts) are reasonably "fresh" (not
all flattened out with the rubber extruding well past the metal spacers,
with vertical cracks in the OD). This includes the nose gear. The
difference in cushioning, and in landing impacts (and taxi/departure
impacts), both grass and paved, is night and day. Ask someone who recently
replaced their donuts.
Keep approach speeds low. Most of these turf fields are much shorter than
you are accustomed to. While you need to make soft landings rather than
"carrier plunks", you can't afford to float forever with partial power still
on (as so many seem to do on paved runways).
Remember that brakes will be nearly ineffective on turf at any significant
speed; the wheels will just lock up. Be prepared to do a deliberate
low-speed ground loop, with braking on one side assisted with rudder, to
avoid going straight into any departure-end obstacles. Most low-speed
ground loops are non-events in planes like ours, but few people mentally
prepare to do them deliberately. At low speeds they are pretty effective at
dissipating energy without damage. I DO NOT advocate any deliberate
practice, for obvious reasons! They can also help on pavement, but the
added tire grip makes them much riskier on paved surfaces (tipping, wingtip
contact, quartering tip-up or nose-over with prop strike, etc.). At slow
speeds I would still choose to attempt one on pavement, if it might keep me
out of certain contact with hard obstacles or a ditch ( or from going over a
cliff?!).
Hold enough takeoff back pressure to relieve the nosewheel load, but not
enough to raise it clear. On firm turf (which is all you should be using),
that will provide the best compromise between added acceleration drag and
reduced impact loads on the nose structure.
Use at least one notch of takeoff flaps for much the same reasons. If you
are comfortable with it, adding a second notch will pop you off the ground
earlier, when you get fast enough. The speed varies with aircraft, loading,
weight, power, etc., but usually is pretty close to the published stall
speed.
Climb at Vx rather than Vy; with two notches of flaps, the charts often
suggest climb speeds below Vx. Leave on one notch of flaps (or both notches
if you used two) until you approach Vy. By Vy flaps are generating more
drag than lift, but I rarely retract flaps until I am clear of obstacles,
except at large paved fields. Our planes tend to make a small nose-dip on
flap retraction, until you have begun to subconsciously correct for it.
Read the performance charts on BAC for these operations at the lower end of
the performance envelope. There is a ton of good info there. Could save
your bacon and airplane some day.
Practice these methods on pavement. Once you are comfortable with your
departure technique, and are doing it well, you can play it safe and add
maybe 20% to the "departure distance for obstacle clearance" that you are
achieving. It is a virtual certainty that you will find that number to be
well within your capability on a 2,100 foot strip.
BEWARE OF TALL GRASS! It is like operating in glue, especially when wet
with dew or recent rain. If a field is not being mowed frequently, or there
seems to be a likelihood of minimal field maintenance, look elsewhere.
And finally, check your insurance policy. Some still exclude operations on
unpaved fields.
_____
From: musketeermail@yahoogroups.com [mailto:musketeermail@yahoogroups.com]
On Behalf Of ke4oh
Sent: Thursday, October 20, 2005 9:57 AM
To: musketeermail@yahoogroups.com
Subject: [musketeermail] Grass Field Operations
Does anyone have experience operating one of our birds regularly from a
grass field? The FBO situation at my current (paved) field is beginning
to be a real headache.
There are two decent grass fields near me (one 2100 ft, the other 2400
ft) that I'm considering moving to. Both are relatively smooth and are
well taken care of.
So, what is the real-world experience with a steady diet of turf
runways? Is this a realistic possibility? Will I have any long-term
maintenance issues due to our stiff landing gear?
Best regards,
Steve Robertson
N4732J 1967 Super III
_____
_______________________________________________
BAC-Mail mailing list
BAC-Mail@beechaeroclub.org
http://www.beechaeroclub.org/mailman/listinfo/bac-mail