Warbirds difficulty to land
08-09-2020, 10:12 AM
#76
Orthobird,
Just an FYI. Here are guys in the jet forum having issues with Xicoy CG as late as today. I did not read it, because I already know that there are issues.
Xicoy Electronic C.G. Balancer
Just an FYI. Here are guys in the jet forum having issues with Xicoy CG as late as today. I did not read it, because I already know that there are issues.
Xicoy Electronic C.G. Balancer
08-10-2020, 07:41 AM
#78
My Feedback: (21)
Having flown all of the TF giant war birds here is my two cents worth.
Yours is way too heavy for the std Robart gear, my guess is that the gear pins bent when you made your turn at the end of the runway. You can replace the pins with hardened
piano wire, get aluminum replacements for the nylon gear sides from Sierra or replace the gears with the Sierra units. I have done all three, P-51s have a tendancy to hop sidewides as they slow down on landing (this was a problem with real p40s and p51s. Solution was the lengthen the tail strut to keep the tail surfaces from blanking out when the tail drops on landing, This also works on the models) Unfortunately the heavier Sierras bent just like the Robarts when the plane hopped sideways as it slowed down. The side loads on the gears is way more than you think. The only solution is too keep the plane around the specified weight ~ 22lbs. It is a real catch 22,
you don't strengthen the wing and it tears the gear out, you strengthen the landing gear mounts and the gear bends, after watching 5 or 6 of the TF 51s do that I completely unskinned the wing of the ARF and found out that they had put the shear webbing in with the grain running crosswise instead of up and down! It would actually tear the spar out of the wing if you beefed up the landing gear mounts. The bummer is that if you leave the plane alone and fly it with the intended size motor at the intended weight it does just fine, lands nice an slow and rolls out straight (most of the time!) Add a few more pounds and it turns into a real monster on landing.
I have seen some of the best pilots around tear the gear out after making a normal landing.
Yours is way too heavy for the std Robart gear, my guess is that the gear pins bent when you made your turn at the end of the runway. You can replace the pins with hardened
piano wire, get aluminum replacements for the nylon gear sides from Sierra or replace the gears with the Sierra units. I have done all three, P-51s have a tendancy to hop sidewides as they slow down on landing (this was a problem with real p40s and p51s. Solution was the lengthen the tail strut to keep the tail surfaces from blanking out when the tail drops on landing, This also works on the models) Unfortunately the heavier Sierras bent just like the Robarts when the plane hopped sideways as it slowed down. The side loads on the gears is way more than you think. The only solution is too keep the plane around the specified weight ~ 22lbs. It is a real catch 22,
you don't strengthen the wing and it tears the gear out, you strengthen the landing gear mounts and the gear bends, after watching 5 or 6 of the TF 51s do that I completely unskinned the wing of the ARF and found out that they had put the shear webbing in with the grain running crosswise instead of up and down! It would actually tear the spar out of the wing if you beefed up the landing gear mounts. The bummer is that if you leave the plane alone and fly it with the intended size motor at the intended weight it does just fine, lands nice an slow and rolls out straight (most of the time!) Add a few more pounds and it turns into a real monster on landing.
I have seen some of the best pilots around tear the gear out after making a normal landing.
08-11-2020, 02:05 PM
#79
Having a ghoulish interest in watching Youtube videos of failed landings, as the OP describes, I came to the conclusion that a lot of these troubles (when not caused by unstable approaches) may be a function of differing grass-lengths and the state of the field. As any glider-pilot will tell you, the difference in landing-distance and between landing in "long grass" to "short grass" is pretty startling, and of course "long" grass can hide all manner of 'orrible ruts and whatnot which can really make the final landing roll a thing of elegance and judgement - if you miss them - or a wince-inducing "arrival" if not.
As effectively you're always landing in "long grass" with a reduced scale aircraft, it stands to reason that warbirds will generally not touch down without frequently nosing over, removing the undercart or otherwise bouncing back airborne at an embarrassingly low IAS; unless the field is both really level, and more like a golfing green than a fairway, IYSWIM.
I'm not an RC pilot yet, but am I on the right-lines here?
As effectively you're always landing in "long grass" with a reduced scale aircraft, it stands to reason that warbirds will generally not touch down without frequently nosing over, removing the undercart or otherwise bouncing back airborne at an embarrassingly low IAS; unless the field is both really level, and more like a golfing green than a fairway, IYSWIM.
I'm not an RC pilot yet, but am I on the right-lines here?
08-12-2020, 09:22 AM
#80
My Feedback: (2)
I think most flying fields cut their grass to suit the planes flying. Long grass is a relative word. I have flown at a lot of fields over the years and most don't have long grass. Most have medium to short grass.
So I would remove the grass length from the equation.
The number one reason for failed landings is not using power to control the planes decent but rather using elevator to control the decent. Ultimately you have too much inertia and can't bleed of sufficient speed and bounce. And bounce and bounce.
So use THROTTLE control Decent. You'll be much better off.
So I would remove the grass length from the equation.
The number one reason for failed landings is not using power to control the planes decent but rather using elevator to control the decent. Ultimately you have too much inertia and can't bleed of sufficient speed and bounce. And bounce and bounce.
So use THROTTLE control Decent. You'll be much better off.
