Go Back  RCU Forums > RC Airplanes > RC Warbirds and Warplanes
Reload this Page >

Warbirds difficulty to land

Notices
RC Warbirds and Warplanes Discuss rc warbirds and warplanes in this forum.

Warbirds difficulty to land

Old 08-05-2020, 12:17 PM
  #51  
BobH
My Feedback: (2)
 
Join Date: Mar 2003
Location: Springfield, VA,
Posts: 7,999
Likes: 0
Received 10 Likes on 10 Posts
Default

Just remember its hard to make a good landing from a bad approach.
Sq feet don't really matter. Especially with large planes. Qubic feet is what really counts. You should be ok.

Last edited by BobH; 08-05-2020 at 01:02 PM.
Old 08-05-2020, 12:20 PM
  #52  
orthobird
My Feedback: (1)
 
Join Date: Dec 2011
Location: shreveport, LA
Posts: 768
Received 0 Likes on 0 Posts
Default

thank you so much Bob! I appreciate the reassurance. Yes, I have read on here, do not hesitate to do a fly around!

Ok, so I am thinking, for the maiden, take off, and do few passes to make sure to trim the aircraft so she flies straight, and then immediately start to work on getting the approach to land?

Old 08-05-2020, 01:05 PM
  #53  
BobH
My Feedback: (2)
 
Join Date: Mar 2003
Location: Springfield, VA,
Posts: 7,999
Likes: 0
Received 10 Likes on 10 Posts
Default

That sounds like a good plan. Once trimmed you can begin to plan your landings using throttle and not elevator. Get a few decent approaches under your belt and then set her down. You'll be pleased at your landing.
The following users liked this post:
orthobird (08-05-2020)
Old 08-05-2020, 01:11 PM
  #54  
RCFlyerDan
My Feedback: (53)
 
RCFlyerDan's Avatar
 
Join Date: Apr 2002
Location: Cape Coral
Posts: 1,664
Received 7 Likes on 7 Posts
Default For the maiden

May I recommend and something that I do for the maiden of Warbirds and Jets. Everyone thinks that it is great to trim the aircraft out at full throttle with flaps and gear up. Run the timer and fuel out. Then, they donít trim for landing and rush the approach to landing. This usually results in a poor landing. My procedure is to roughly trim the aircraft 1/2 throttle, flaps and gear up. Then, at half throttle, extend the gear and flaps. Now do a race track pattern maintaining level flight, trim the aircraft 1/2 throttle, gear and flaps down, for hands off flight. Now the plane is trimmed for landing. Give yourself 3-4 minutes to do this and to give you a couple practice approaches. Donít reduce throttle below a quarter, until the approach that you feel comfortable, and landing is assured. All you want to see is the leading edge coming down final. If you see the top of the wing, youíre too fast. If you see the bottom of the wing, you are too slow and/or too high. Full scale glide slope is 3-3.5 degrees decent angle. Also consider using ďcrowĒ. This gives wash out at the wing tips.
The worst approach is to come in high, chop the power and dive for the runway. It isnít a stabilized approach.

Also, double check the CG the manual way. I went to maiden a CARF Viper for a buddy. He was using the Xicoy balancer. Iím sure that he didnít measure correct. It wanted him to add 2# to the nose. I had him take what weight he already installed and moved the batteries back. I set his up to mine, and had an easy maiden.

Last edited by RCFlyerDan; 08-05-2020 at 01:17 PM.
The following users liked this post:
orthobird (08-05-2020)
Old 08-05-2020, 07:20 PM
  #55  
orthobird
My Feedback: (1)
 
Join Date: Dec 2011
Location: shreveport, LA
Posts: 768
Received 0 Likes on 0 Posts
Default

thank you so much! I will do that also. sounds like a great idea.

So for crow? you mean., as i put on mid flaps, also program so that my elevators go down by 2 or 3 degrees, and also for my ailerons , both of them, to move up by 2 to 3 degrees?
Old 08-05-2020, 09:17 PM
  #56  
perttime
 
perttime's Avatar
 
Join Date: Dec 2005
Location: Tampere, FINLAND
Posts: 1,674
Received 4 Likes on 4 Posts
Default

Yes. Crow means flaps down, ailerons up.
Different designs require different elevator inputs with flaps. Could be up, could be down. If you have advice for your specific model design, follow that. Or be prepared to trim.
The following users liked this post:
orthobird (08-06-2020)
Old 08-06-2020, 02:37 AM
  #57  
orthobird
My Feedback: (1)
 
Join Date: Dec 2011
Location: shreveport, LA
Posts: 768
Received 0 Likes on 0 Posts
Default

Originally Posted by RCFlyerDan View Post
May I recommend and something that I do for the maiden of Warbirds and Jets. Everyone thinks that it is great to trim the aircraft out at full throttle with flaps and gear up. Run the timer and fuel out. Then, they donít trim for landing and rush the approach to landing. This usually results in a poor landing. My procedure is to roughly trim the aircraft 1/2 throttle, flaps and gear up. Then, at half throttle, extend the gear and flaps. Now do a race track pattern maintaining level flight, trim the aircraft 1/2 throttle, gear and flaps down, for hands off flight. Now the plane is trimmed for landing. Give yourself 3-4 minutes to do this and to give you a couple practice approaches. Donít reduce throttle below a quarter, until the approach that you feel comfortable, and landing is assured. All you want to see is the leading edge coming down final. If you see the top of the wing, youíre too fast. If you see the bottom of the wing, you are too slow and/or too high. Full scale glide slope is 3-3.5 degrees decent angle. Also consider using ďcrowĒ. This gives wash out at the wing tips.
The worst approach is to come in high, chop the power and dive for the runway. It isnít a stabilized approach.

Also, double check the CG the manual way. I went to maiden a CARF Viper for a buddy. He was using the Xicoy balancer. Iím sure that he didnít measure correct. It wanted him to add 2# to the nose. I had him take what weight he already installed and moved the batteries back. I set his up to mine, and had an easy maiden.

I just recalled, my radio will allow me to do that, meaning, it has the ability for me to set flight modes, and for example, I have already programmed the following three modes:

1. cruise (this has flaps up)

2. Mid flpas

3. full flaps


and I can also trim the aircraft in each mode, meaning, when i flip the switch to another mode, the trim from one mode does not carryovers to the other mode.
Old 08-06-2020, 04:31 AM
  #58  
RCFlyerDan
My Feedback: (53)
 
RCFlyerDan's Avatar
 
Join Date: Apr 2002
Location: Cape Coral
Posts: 1,664
Received 7 Likes on 7 Posts
Default My practice setup

Originally Posted by orthobird View Post
I just recalled, my radio will allow me to do that, meaning, it has the ability for me to set flight modes, and for example, I have already programmed the following three modes:

1. cruise (this has flaps up)

2. Mid flpas

3. full flaps


and I can also trim the aircraft in each mode, meaning, when i flip the switch to another mode, the trim from one mode does not carryovers to the other mode.
Good Morning,

That is great! Usually a P-51 has 2-3 degrees of elevator down trim. You can preprogram the elevator for a rough start. Now, if your radio has the ability, set the elevator trim up for fine tuning on a knob at 10% adjustment. Both the knob and the elevator trim tab will trim the elevator. Gear and flaps up, use the regular trim tab. Then when extending flaps, use the knob when flying the race track pattern in level flight. This gives you two trim settings. The elevator trim is set now with flaps up for the next takeoff. Then the knob setting, you add or subtract the trim percentage from the programmed elevator down trim with flaps full down. Donít use more than 60 degrees of flaps. 45 degrees is better. The more flaps that you have, the less you can increase the AOA(Angle of Attack). Or the sooner that it will stall in level flight.
On the ďCrow ď, you have to do two mixes for each aileron assigning the Flt Mod Sw or the Flap Sw. So, Flap to Aileron left and right, and I use 20% in the radio numbers. This gives about 5 degrees up aileron with full flaps. This set up allows for a greater AOA. This setup is for a two wheel landing. If you want to 3-point land the plane, donít use more than 30 degrees of flaps. The more flaps, the less that you can increase the AOA in the flair. This is why you will see some guys tip stall it in during the flair or base to final. Too much flap! This setup is for a flat full scale approach. You will carry 1/4-1/3 power setting until about 3-5 feet off of the ground. This is if your engine throttle is set up right. Half throttle has to be half of the power(rpms) If you havenít owned a DA, they are extremely reliable, even when new. Also, on a DA, if it doesnít start by the fifth flip after the pop, something isnít set up right.
The following users liked this post:
orthobird (08-07-2020)
Old 08-07-2020, 06:34 PM
  #59  
orthobird
My Feedback: (1)
 
Join Date: Dec 2011
Location: shreveport, LA
Posts: 768
Received 0 Likes on 0 Posts
Default

thank you so much!

All great advice.

another question, how much deflection on the ailerons and elevators?

10 degrees each way on both? or do I need more?
Old 08-08-2020, 05:09 AM
  #60  
RCFlyerDan
My Feedback: (53)
 
RCFlyerDan's Avatar
 
Join Date: Apr 2002
Location: Cape Coral
Posts: 1,664
Received 7 Likes on 7 Posts
Default

Originally Posted by orthobird View Post
thank you so much!

All great advice.

another question, how much deflection on the ailerons and elevators?

10 degrees each way on both? or do I need more?
I donít know what you have flown prior to this P51. The old statement, ďLess is More.Ē is very true with high performance Warbirds. If you havenít flown a fully symmetrical stab, they are very efficient and effective. So, the elevator needs far less movement than most think. Please understand that the manufacturerís recommendations are usually on the very conservative side, with hopes that the customer succeeds with their plane. Iím looking at your wt/bal again on the Xicoy. I donít know if the picture truly represents your plane. If it does, then you need to move the CG behind the main wheels. Otherwise, you will be tipping over on the nose and ruining cylinder heads and props. I bought a TF kit built P-51, not an ARF, cheap at a Warbird Event. The guy sold it because he was frustrated trying to land it. I bought it after his last bad on the nose landing. His CG was in front of the wheels, which is a no-no with any taildragger. I took 3 1/2 pounds of lead out of the nose!!! It flew beautiful after that and other setup issues. My flying buddies and I couldnít believe it. So, if you have to, add tail weight, or move batteries further back.
Back to flight controls and Less is More. I would use the low rate recommendation from TF with 15-20% expo. If you have flown warbirds, then you understand. If you are coming from IMAC style Extras, then you will think that you need more control. Trust me, you donít. P-51ís should be flown with graceful and sweeping turns. Smooth movements. Not bank and yank. With the heavier wing loading, if you bank and yank, it will do an accelerate stall, snapping and spinning into the ground. Another recommendation for your wheels and gear. Only have 1 to 1 1/2 degrees of toe in. I use a square for the adjustments.
Here is the recommendations from the TF manual.


Use Low Rates!
Old 08-08-2020, 05:13 AM
  #61  
RCFlyerDan
My Feedback: (53)
 
RCFlyerDan's Avatar
 
Join Date: Apr 2002
Location: Cape Coral
Posts: 1,664
Received 7 Likes on 7 Posts
Default Wt/bal

In case you havenít seen this forum.

Xicoy Electronic C.G. Balancer

Old 08-08-2020, 05:21 AM
  #62  
orthobird
My Feedback: (1)
 
Join Date: Dec 2011
Location: shreveport, LA
Posts: 768
Received 0 Likes on 0 Posts
Default

thank you again

I measure the CG, and it is 3 mm forward to the recommended area.

I did use the Xicoy, and was very careful to measure the distances several times

In computer navigation world, we say, garbage in = garbage out.




Old 08-08-2020, 05:59 AM
  #63  
RCFlyerDan
My Feedback: (53)
 
RCFlyerDan's Avatar
 
Join Date: Apr 2002
Location: Cape Coral
Posts: 1,664
Received 7 Likes on 7 Posts
Default

That looks better. Another thing that I see now is your lateral balance. You are almost a 3/4 of a pound heavier on the left side. With P-factor and a LOT of power, this could end in a left hand cartwheel on takeoff.
The following users liked this post:
orthobird (08-08-2020)
Old 08-08-2020, 07:19 AM
  #64  
Lifer
My Feedback: (1)
 
Lifer's Avatar
 
Join Date: Aug 2008
Location: Kansas City, MO
Posts: 4,327
Likes: 0
Received 8 Likes on 8 Posts
Default

A big Plus 1 on what RCFlyerDan has posted. For Top Flite warbirds in particular, follow the manual!!! 3.5 pounds of lead in the nose is absurd. Too many people quote that old saw about the benefits of nose-heavy airplanes and then aren't successful. Gracefully balanced is the best. Excessive control throws are another major error. I have heard a lot of people say that they like the extra throw to get them out of trouble when in-fact the excess throw is what gets them in trouble in the first place. I watch(study) warbird videos in order to learn from others mistakes. When it comes time to flare for the landing, an instant zoom climb is evidence of excessive elevator throw. Another giveaway is a mild to hard left turn on every takeoff, but that's another issue.
Old 08-08-2020, 07:23 AM
  #65  
perttime
 
perttime's Avatar
 
Join Date: Dec 2005
Location: Tampere, FINLAND
Posts: 1,674
Received 4 Likes on 4 Posts
Default

Yep. That really jumps out. Why is the left side so much heavier? Sounds like trouble, unless you fix it.
Old 08-08-2020, 02:25 PM
  #66  
orthobird
My Feedback: (1)
 
Join Date: Dec 2011
Location: shreveport, LA
Posts: 768
Received 0 Likes on 0 Posts
Default SO what really happened today???

SO what really happened???got to the club at around 12:30 pm

some of the club members were there, my friends.

They helped me and gave great advice on flying, flaps, crow, and landing.

1st thing:

My xicoy scale is wrong for three reasons:

1. it stated the lateral balance was off by 3/4 pounds!

when I got there and got the wings, one of the members and i tested the lateral balance of the wing alone, and it was perfect. well balanced.

then we assembled it to the fuselage, and it too was perfect. Not 3/4 pounds heavier on left side, as the Xicoy stated.

#2. it states the airplane is nose heavy. when we did it with finger tips, no matter what we did, the airplane was quite tail heavy!

we tested it with wheels up and wheels down, and with airplane up right and inverted. No matter what, it was always tail heavy.

then I moved the batteries forward,. and it became balanced based on recommend CG point from the manual.

Once we got that straightened out, i fueled her up and cranked her on.

She was humming and that twin cylinder sounds very nice.


SO then, I got her on runway and did some taxing back and forth. I was gaining confidence.

I then brought it back and killed the motor, then took some pictures.














Waited a while, drank some water. then I said, this is it, I'm going to do it.


I then cranked her on again, tax to the north end of the run way, do the 180 degree turn to get the nose pointing south, and then i slowly increased power. I was at 1/4 throttle, and all of a sudden, the low end leaned out some, and the RPM picked up. tail still had not elevated, and i slowly applied rudder to left as it was slightly coming in towards the fence side, and as soon as I did that, the left Robart retract kind of got bent or something.


SO nothing bad happen. No prop strike, no damage, other than the left Robart gear. SO I killed the motor, packed it up, and here I am typing.


I am going now to try to see what to do next.


Probably the 31 pounds are not helping. too much stress for that gear, I am thinking.






Old 08-08-2020, 02:58 PM
  #67  
orthobird
My Feedback: (1)
 
Join Date: Dec 2011
Location: shreveport, LA
Posts: 768
Received 0 Likes on 0 Posts
Default

found the culprit:



Old 08-08-2020, 03:43 PM
  #68  
RCFlyerDan
My Feedback: (53)
 
RCFlyerDan's Avatar
 
Join Date: Apr 2002
Location: Cape Coral
Posts: 1,664
Received 7 Likes on 7 Posts
Default It lives for another day!

Orthobird!

Iím so glad that you did the finger balance and manual lateral balance. Tried and true. Iím glad that you didnít have a prop or engine strike. Now that you have mentioned that the engine changed during takeoff; I meant to ask you if you baffled the rear cylinder? It has to be done. Call DA and ask for directions. You also need 1 in 3 out air ratio for air flow through the engine cowling. Maybe more for a 100.
The Robart issue is common with a heavy plane. They are more for 25# and under, so any side load destroys them. Always come to a stop before any turns. I canít remember the other better quality brand right now. A little help guys? I think his name is Darrel and make them for the Ziroli P51 and CARF.
The best retract that I only buy are Behotec. They are mostly jet retracts and indestructible. The C40 or C50, depending if it would fit the thickness of the wing. Mounts can be modified. But, it would be easier and better to go with a set from the quality built retracts if he makes an exact swap out.
I am truly thankful that you manually checked the balances!!! Keep after the details!

Last edited by RCFlyerDan; 08-09-2020 at 03:56 AM.
The following users liked this post:
orthobird (08-08-2020)
Old 08-08-2020, 04:14 PM
  #69  
BobH
My Feedback: (2)
 
Join Date: Mar 2003
Location: Springfield, VA,
Posts: 7,999
Likes: 0
Received 10 Likes on 10 Posts
Default

The better retracts are made by Sierra Giant Scale.
Glad nothing untoward happened except the gear failure.
Old 08-08-2020, 06:14 PM
  #70  
orthobird
My Feedback: (1)
 
Join Date: Dec 2011
Location: shreveport, LA
Posts: 768
Received 0 Likes on 0 Posts
Default

thank you Bob, I will look them up

I have almost had enough of Robart.
Old 08-09-2020, 03:27 AM
  #71  
Tony Gag Jr.
My Feedback: (124)
 
Tony Gag Jr.'s Avatar
 
Join Date: Jan 2002
Location: Terryville, CT
Posts: 1,132
Likes: 0
Received 1 Like on 1 Post
Default

Definitely go with Sierra, totally different league than Robart. Robart are junk and a portion of them, like yours, have design flaws.
Old 08-09-2020, 03:45 AM
  #72  
RCFlyerDan
My Feedback: (53)
 
RCFlyerDan's Avatar
 
Join Date: Apr 2002
Location: Cape Coral
Posts: 1,664
Received 7 Likes on 7 Posts
Default Thanks guys!

Sierra! Thatís the gear! Thanks guys!

P-51 Retracts

Old 08-09-2020, 04:02 AM
  #73  
Lifer
My Feedback: (1)
 
Lifer's Avatar
 
Join Date: Aug 2008
Location: Kansas City, MO
Posts: 4,327
Likes: 0
Received 8 Likes on 8 Posts
Default

I can't classify Robarts as junk. They are designed for a specific weight range, and if you double that load, failure is a reasonable expectation. I have several sets of Robarts and some have been in service for almost 10 years.
Old 08-09-2020, 04:07 AM
  #74  
Tony Gag Jr.
My Feedback: (124)
 
Tony Gag Jr.'s Avatar
 
Join Date: Jan 2002
Location: Terryville, CT
Posts: 1,132
Likes: 0
Received 1 Like on 1 Post
Default

We can agree to disagree on Robart gear. I think they are junk and the design flaws are just unacceptable. Take a look at the design on the TF FW-190, total failure of a design. Has nothing to do with the weight of the plane.
Old 08-09-2020, 06:17 AM
  #75  
Lifer
My Feedback: (1)
 
Lifer's Avatar
 
Join Date: Aug 2008
Location: Kansas City, MO
Posts: 4,327
Likes: 0
Received 8 Likes on 8 Posts
Default

I agree with you in regards to the FW gear. They failed to consider the power of a lever. The long gear simply overwhelmed the interior design of the retract mechanism itself. A complete re-design was called for, but economics ruled that out. They had to meet a price point dictated by Tower so off-the-shelf equipment was used.

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.