chadxp1

My Feedback: (2)

I have a 40 size corsair. I bought it used. I took it out today for a maiden of my own but could not taxi because the noze kept tipping over. The field I fly off of is rough. What can I do to overcome this? The elevator does not have much throw. I did have the elevator advanced to the up position while trying to taxi but it did not help. The COG seems to be fine. The wheels are big enough I guess (3-3.25"). Other than finging a flatter field what can I do to keep the tail down?

Chad

1320Fastback

Other than full up elevator there's not much.

If it does not have retracts you could see if you can bend the gear forwards a little.

OR

Smooth the runway and forget taxiing

AB Bob

My Feedback: (20)

You need to get the wheels further forward. I'm not sure what type of landing gear you have, but you can either bend the wire or, perhaps shim the mounts to get the wheels more towards the leading edge. I had to do this (bent landing gear wires) on a Tower Hobbies P-51 foamy.
Good luck
Bob

radius1x1

I have the same problem with my Corsair in tall grass: however, if I rev the hell out of it with full elevators; it will take off. Not scale mind you, but it does get off the ground!

flyinwalenda

My Feedback: (5)

As stated rake the gear forward. The center of the wheel should be flush with the leading edge when looking from the side with wings level. Also increase the throw of the elevator and program dual rates if you can. Move the clevis to a hole in the elevator horn closer to the control surface as long as it doesn't bind and readjust for trim .

Steve Steinbring

Setting the landing gear a bit more forward will certainly help and high grass is always a problem at times.


All though the above is certainly a technique, it may lead to a takeoff stall if the airplane comes off the ground too early!

I would definitely add power slowly to full throttle starting with full up elevator to get the airplane rolling allowing it to accelerate getting the tail off the ground. At the same time anticipate that some right rudder will be required to compensate for the torque of the engine. As the takeoff speed increases and rudder becomes more effective decrease the elevator/rudder pressure and letting it fly off by itself.

JohnBuckner

My Feedback: (1)

Actually the takeoff technique mentioned by radius is effective When considitions of tall grass or rough ground and maybe a gear with retracts that are a bit to far aft.

As matter of fact when conditions like that exist the worst thing you can do with most warbirds is a slow throttle up scale like takeoff. If what is know as race starts in warbird racing were not allowed then most race would never happen with airplanes scattered all over the takeoff grounds.

The technique requires a team of two. The caller will place the airplane on the wheels in takeoff position and direction but not let go. The pilot will usually position the elevator in the full up position and the rudder in the full right position and when ready and then the pilot will run power up to at least half or more (can be as much as full power) and only after engine become stabile at the high power will the pilot nod his head and caller will simply release the airplane (not push as in some forms of racing starts).

This requires no immediate action from the pilot at release the noseover tendency will be gone and just before the liftoff the elevator and rudder is returned to neutral as normal. This sounds difficult and spectacular but it requies the least of the pilot during the takeoff and it works. Yes of course if you hang onto the full up to long that's not good and really not good just as when you hang onto up too long during a long protracted takeoff run.

Yes scale like is pretty but whenever considtions are difficult a 'race start' is more effective and less difficult, its worth learning. If you ever attend a warbird race that is likely all you will see.

John

koastrc

Well said John. I have had the pleasure or horror to test hop many new aircraft. War bird ground handling has always been a test of experience. Grass fields and little wheels. A real bad mix. A fast roll is better than a slow roll if we are talking take off on grass.

Steve Steinbring

John,

Yes, that technique will certainly work, but not all fields readily allow race starts with people on the runway for takeoff we pretty much strictly fly from the pilot boxes. Since our runways are essentially golf course fairway quality mowed very close its not all that much of an issue where we fly. Do what works for the situation.

Steve Steinbring

http://www.modelaviation.com/masteringtakeoffs

Hossfly

Rough fields and a warbird, especially a Corsair, can well be a handful. Now here are a couple tips that always seem to help.
1. Tire-toe-in at least 2 degrees maybe 3-4.

2. While not really a taxi-thing depending on wind it can help and certainly assists for nice take-offs. Be sure each aileron is rolled up from 3-5 degrees above the flap line.
All airplane wings are washed out. In the normal SCALE / SPORT SCALE model, unless you build it such, the model will not have washout. Rolling the ailerons up a tad will offer much assist in take-off and in all maneuvers. For example the real P-51 (F-51) had about 17 degrees "down" aileron and 27 degrees "UP". That "washout" was a strong assist when in maneuvering where it was needed. Our scale models need washout to assist take-off and landing maneuvering, plus it makes airborne maneuvering much nicer. Now, OTOH, you 3-D and pattern types are on your own.
Washout for take-offs allows for a tad more speed needed on the TO roll, which reduces the aileron often used where rudder is actually needed. Try it as I think you will like it.
Remember when taxing out to hold full UP-Elevator, frequent short bursts of power, one after the other, (Constant throttle will accelerate the taxi more and create a fast taxi with the tail bumping up and down - not good) and ailerons full up into the wind.

jaka

Hi!
The first thing I would check is the Cof G!
A nose heavy plane easily tips over forward, so how is it felt in the air?? Nose heavy or tail heavy??

chadxp1

My Feedback: (2)

Guys the "race start" did the trick! I was able to maiden the airplane. It flew real nice. I was a little caught by how slowly she rolls. Doing a barrel roll was a little difficult in relation to my 3D planes. Anyway back to the takeoff, it worked real well. I actually performed this maneuver twice. Hold, the tail, rev the engine full power, full elevator, release the airplane while gradually decreasing elevator till speed increases. No problems tipping over. I am looking forward to flying this beautiful airplane all summer long. Thanks for the help and other suggestions.

Chad

JohnBuckner

My Feedback: (1)

Thanks Chad, delighted the race start worked for you. A very useful tool at times under certain considtions with some types of airplanes.

John

JendaDH

Hi

not very scale, but you can try to go with larger wheels if you don't have retracts to overcome rough airfield...

CGRetired

My Feedback: (1)

I watched a video that was produced a few years ago about operational training for pilots learning to fly the B25. It was a composite of real training given during WW-II and more modern cuts inserted using a restored aircraft. One point that was driven home was the importance of a three wheel take off by leaving the tail wheel on the ground up to lift off. It was a mix of drag lift weight on wheels and thrust along with maintaining the proper angle of attack. It was really informative and interesting.

Villa

I believe that most R/C pilots land with the throttle at full idle. Since your elevator moves very little, I suggest you land with 2-3 clicks, or more, of throttle above idle. This will make the elevator more effective to keep the tail down. As others have suggested, move the mains more forward.

600Bob

Washout is a twist in the wing and having both ailerons up slightly above the trailing edge can simulate it. It is used so the wing stalls from the center before the tips.

Giving the aileron less down travel than up travel is called differential and is not the same as washout. It is used to offset adverse yaw caused by the lowered aileron creating more drag than the up aileron.

Hossfly

And your point/s is/are ????

My explanations are/were aimed at the modeler that may have little or no 1:1 scale fine print in his understanding of what happens / can happen with a wing, and subsonic convergent airflow, along with a model's aerodynamic situations. My terms were presented to provide usable information for the RC modeler that in most cases has little opportunity to study the mass of applied aerodynamics within the realm of such aircraft. Unless I build in "washout" it isn't there. Howeve I know how to fudge it.
OTOH you know how to read the book. Yet I doubt you are well informed in the practical daily use of those tools at hand for use to obtain the best results.

So many models are rigged with equal aileron movement, a MUST for competitive aerobatics. For a scale model, usually more wing-loading, the equal movement can be replaced by rigging the less aileron "down" movement. Then as YOU stated the Scale model RC pilot is better served because he doesn't get all that adverse yaw when the model is lifted off the ground with the usual >>> model tries to torque left, pilot applies right aileron WRONG, should be right rudder

Charlie P.

I've added washout where needed by lengthening the aileron control linkage so each aileron is a little elevared at neutral stick. Only takes a few degrees.

ec121

My Feedback: (2)

I had a plane that would tip over like that. Got around it by putting my toe on the tailwheel and going to full throttle. Wait a sec for the air to get on the rudder and let it go with about half or so up elevator. Once they ever get rolling the takeoff is a non-event. It will fly when ready.

600Bob

My reason for comment was that in your original description you only mentioned washout and you seemed to be describing the settings for differential as if it were washout as well. If you had said "this is washout and it does this, and this is differential and it does something different" then I wouldn't have commented.