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-   -   TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE (https://www.rcuniverse.com/forum/rc-warbirds-warplanes-200/10966879-top-flight-giant-p51-ground-handling-issue.html)

AFTERBURNER1 02-19-2012 08:53 PM

TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
I have a DA50 powered Top Flight Giant P51 with Sierra scale gear and wheels...

First of all...... Flys great, takes off great and finally,, lands great!!!

The issue is after the tail wheel drops it is a squirrelly pain in the shorts..

Yes, it rolls straight and the tail wheel has no slop... Plenty of flap for nice slow touch down and a bit of toe in on the mains...

What's the cure??? I was thinking about adding some nylon washers to the main wheel axles to add a bit of drag.

This help???


Thanks

Ram-bro 02-19-2012 09:17 PM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
might put you over on your nose....

Chad Veich 02-19-2012 09:25 PM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
Where you need the drag is on the tailwheel. Kind of like a tail on a kite. You might try reducing the tail wheel steering movement, or adding some expo. What you describe is not uncharacteristic for many warbirds that have long gear legs and it may not be curable competely.

Chad Veich 02-19-2012 09:32 PM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
One other thing I've found that may help is to 3-point the airplane if you can do it without fear of tip stalling. It is usually in that transition between tail up to tail down that the changing gyroscopic forces cause all sorts of issues. If you land 3-point you've cleared that hurdle already and it becomes much easier to manage the rudder properly to keep the airplane going straght. My .02 cents of course.

Brad330l 02-19-2012 10:52 PM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
If you are landing on a hard surface try taking the toe in out. Simple to do and costs nothing.
Through the development of the Spitfire the toe in was reduced as more and more operated of hard runways.

Worth a try at least.

Good luck,

Brad

Walt Thyng 02-20-2012 05:43 AM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
If you have the lg in the scale position, they may be too far back. Best handling comes with the axle in line with or slightly ahead of the leading edge. May be hard to fix, tho.
Walt

skillet92 02-20-2012 07:06 AM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
ESM Mustang with Sierra gear. When I put them in the scale position the plane would VERY easly nose over. I installed 2 flat washers under the back 2 bolts that hold the retract in the wing. Moves the wheels forward to the leading egde and yes it makes the wheels sit in the wheel well a little off. But in the air you can't notice it and the takeoffs and landings got to be a breeze. I also made my rear tail wheel alittle stiff so that it drags a little bit.

larry@coyotenet 02-20-2012 07:53 AM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
I have seen the same problem with most of the TF 51's if your using the scale tires that come with the Robart or Sierra rims. The cure is to replace the hard rubber tires with either the entire Dubro wheels or modify the rubber from the Dubro wheels to fit the Sierra rims. I would try using the stock wheels and rims that come with the ARF and see if that helps.
The stock setup that comes with the arf doesn't have that problem unless the plane is way overweight, like 28LBS or more. Believe me, I have friends who tried every trick in the book to make them track straight on landing and nothing helped until they changed to the Dubro wheels and tires.
Larry

BarracudaHockey 02-20-2012 07:59 AM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
Try some up elevator when its on the ground to hold the tail wheel down.

tail strike 02-20-2012 01:25 PM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 


ORIGINAL: AFTERBURNER1

I have a DA50 powered Top Flight Giant P51 with Sierra scale gear and wheels...

First of all...... Flys great, takes off great and finally,, lands great!!!

The issue is after the tail wheel drops it is a squirrelly pain in the shorts..

Yes, it rolls straight and the tail wheel has no slop... Plenty of flap for nice slow touch down and a bit of toe in on the mains...

What's the cure??? I was thinking about adding some nylon washers to the main wheel axles to add a bit of drag.

This help???


Thanks
A friend of mine had a problem of his Corsar being squrilley after the tail wheel comes down.
He discovered the tail wheel was pretty hard rubber and no tred on it.
He put a DuBro tail wheel (the rubber was softer and had tred) in place of the origonal tail wheel
Problem solved.
The origonal tail wheel was NOT getting any traction to hold the plane straight.

AFTERBURNER1 02-20-2012 04:32 PM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
Good ideas gents,,,, I will replace the tail wheel and look for some tires that will fit the Sierra scale rims.

Anybody ever retrofit new rubber to the sierra rims? If so,,, what brand and size?

AFTERBURNER1 02-20-2012 04:35 PM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 


ORIGINAL: BarracudaHockey

Try some up elevator when its on the ground to hold the tail wheel down.

:eek: ha ha,,,, c'mon man... Taildragger 101...

Peter_OZ 02-20-2012 05:02 PM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
taxi slowly!

MX240 02-20-2012 05:29 PM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
I am on my third TF GS P-51 as I use them for my everyday practice plane and they all have JR Gyros in them with Futaba MZ14 radios and no problems..
I use the Robart retracts with Robart treaded scale wheels. I do use 50% expo on the rudder. I don't use heading hold on the Gyro and it is off for the flight.
JR has come out with a new airplane only Gyro. I have tried Futaba's Gyro's and they suck.

Peter_OZ 02-21-2012 12:09 AM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 


ORIGINAL: AFTERBURNER1



ORIGINAL: BarracudaHockey

Try some up elevator when its on the ground to hold the tail wheel down.

:eek: ha ha,,,, c'mon man... Taildragger 101...

gyro? Really?

Lifer 02-21-2012 03:47 AM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
Afterburner1,

It sounds as if you have flown the plane enough to have it trimmed out. Measure the elevator throw it presently uses and set this up as your "low-rate" setting. Then, set your high rate to and really large amount of throw for the purpose of improved ground handling. The extra down force on the tailwheel might take care of your issue.

Best regards.

larry@coyotenet 02-21-2012 07:20 AM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
You can get the Dubro wheels and breakout the hub. You need to enlarge the center hole and use a dremel grinder to match what the sierra rubber looks like so it will clamp on the sierra rims. Is easier to do than it sounds. If you want to see if that is the problem I suggest using the stock TF wheels and see if that calms down the roll out first. Our warbird group has gone through every suggestion trying to get the TF 51 to roll out straight and this is the only thing that has helped consistently.
Larry

Ron101 02-21-2012 08:57 AM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
I'm going to do the same to mine with the dubro wheels on the aerotech wheels I have, which look the same as robart aluminum wheels.....

I only have two flights but mine also got a little squirrelly after a perfect landing... I have heard over and over through the years to loose the robart rubber on there aluminum wheels, which like I said I think is the same rubber that's on sierra's, robart, and aerotech... it's hard rubber

I have a set of dubros, I'm going to do that mod to mine tonight

AFTERBURNER1 02-21-2012 12:27 PM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
So what size wheels/tires and brand am I supposed to get to retrofit to the aluminum scale rims?

I also got the 1-3/4 treaded soft dubro tail wheel. Is this the right size? The old one was the 2 inch hard as rock dubro smooth tire.

Ron101 02-22-2012 07:27 AM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
1 Attachment(s)
Hey Doug,
I've read about the problem for years and the guys always recommened the Dubro 5" treaded light wheel.

I did mine last night, not big deal at all. I just broke the hub out of the dubro wheel with a few smacks of the hammer. Took apart the aluminum wheel and removed the rubber.
Used an exacto knife to inlarge the center or the dubro wheel and put it back together. The tire needs to be 2 3/4 opening in the center. There is a ridge on the dubro wheel and if you cut 1/16 outside of that ridge it's a perfect fit.

The tires don't feel much different but I know this is what guys do to fix the problem.

Mine got a little nutty on both landings on rollout... so this should do the trick. I also made sure my tail wheel had no slack in the pull pull and but on a better tail wheel....can't remember which wheel.
but it's an aluminum hub with a hard rubber tire. Mine is 27 pounds and it was crushing the dubro tail wheel....

First pic shows the Dubro wheel you need
Next is the stock wheel on the left and the modified dubro wheel on the right
last pic is the dubro wheel on the aluminum rim

MX240 02-22-2012 09:36 AM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
Hi Ron,
Thanks for the pictures and you guys have me convinced that now I need to chage mine even though I'am happy with my Robart tires. But, I wonder if you guys are flying off a hard black top runway as our club flies off a 550' petro mat with a 2" sand base. So there is some "give" on touch down and all the warbird fun flies I go too in the area are either the same or nice grass.

Ron.....also what is that nice scale nose landing gear too in your first picture?
Thanks
Jim

Ron101 02-22-2012 10:28 AM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
1 Attachment(s)
No problem Jim
I fly off asphalt and that is what makes it act silly... I bet off petro mat and grass you will be fine with the stock tires. But beware of hard surface, even after a great touch down at the end of the roll out it does a nutty little dance. Should have it fixed now...


The nose wheel is my long term project, its a yellow aircraft twin F-18 I'm doing up in blue angels... I hope to get it done this year.


Growler84 02-22-2012 12:22 PM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
I've had two TF Giant P-51 ARF's and wrestled with the exact same landing roll out issue. It took the better part of a year to break the code but once I did the plane turned into a *****cat. This is not theory, its many hours of flying experience with this particular model.

The Mustangs short fuselage moment and resulting rake (attitude) when its on all three wheels is what's killing you. The following steps will solve your problem:

1. Make sure the tailwheel is extended as far out as possible.
2. Reduce the main wheel diameter to 4.5 inches, sorry, a bit unscale but so is a plane that does the funky chicken on landing roll out. I use the CBA 4.5 inch wheels from MECOA.
3. DO NOT attempt to three point this plane, wheel land it, let the tail come down on its own, when the tail wheel touches, drive it down the runway until you reach taxi speed. You can stick it with a bit of elevator if you want but its really not required.

Why no 3- point? As many have found out the hard way, if you bounce the model a bit and drop it back down on the mains you are going to break the gear mounts and or wings. In a 3-point attitude if you bounce the plane while presenting all that wing you will become airborne in a slow speed thrust deficient situation. If you don't go around out of it, you will likely break things already mentioned.

Try it out and let us know how it works for you.

flycatch 02-22-2012 02:56 PM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
I had the same problem on my BH Pitts S1S and it's all a matter of incidence angle. The higher the incidence angle of the airframe at rest the more unontrolable the tailwheel becomes. Non scale approach would be to decrease the incidence angle which I did. Another poster decrease the diameter of main wheels thus decreasing this angle. I took the opposite approach and installed and aftermarket Dubro tailwheel assembly. This also decrease the incidence angle and the problem was solved. Take a look at a pattern ship and the incidence angle is marginal. You want the tail up as soon as possible to gain rudder authority and since your not in the cockpit you cheat. Of course you could fly it like the real one.

MX240 02-22-2012 05:35 PM

RE: TOP FLIGHT GIANT P51 GROUND HANDLING ISSUE
 
3. DO NOT attempt to three point this plane, wheel land it, let the tail come down on its own, when the tail wheel touches, drive it down the runway until you reach taxi speed. You can stick it with a bit of elevator if you want but its really not required.

Boy you got that right for just about any warbird and it takes a different mind-set to add power as you get get closer to the runway and I might add on all my 51's I have 3" for landing flap travel with 200oz servos on each channel. On a long past bird I had a bad servo go dead on one side and raise and full aileron at the last minute. Because of my insistence of having a "landing flap" I have declined test flying other peoples heavy warbirds till they get them down their. If they should "hop" back in the air I want it "killed"
immediately. The only exception to a full flap landing is on dead stick which is no flap if you value your landing gear. Don't ask how I know this!!
Sometimes with our long runway I carry a little power just to keep the tail up for looks. :)

Ron..... I see you made a comment on Colonel Thackers's birthday. He use to make the drive to Ida Grove Iowa (mid 80's) when "Sticking Back" at Bryon's was going strong.
He sure didn't have a very fancy motor home in those days....which is nothing wrong with that...but us local guys thinking a Col. pay and everything. :)
I did get a chanch to speak to him back then and was a very active knowable person. Way above me in military rank also. :)

Ya, love your jets. my two favorites are the Nam F-4's and your F-18....super cool.
Jim
Nam 68-69


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