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Old Jul 13, 2011, 02:26 PM
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Sausalito Marin Cty, California, United States
Joined Aug 2004
892 Posts
So, I have a question... Some of these are coming in on balance, and others tail heavy. Has anyone with a tail heavy corsair opened it up to find out why? Seems that one fix is to add weight to the nose, which is what most are doing when the plane is tail heavy. Could the difference be too much glue in the tail? Is there a way to remove excess glue or foam that should have been removed. I'd look on mine, but mine balanced right out of the box.
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Old Jul 13, 2011, 03:09 PM
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United States, FL, St Augustine
Joined Jun 2011
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well this is my understanding of a coordinated turn. its when you add a little rudder in the same direction as the turn you are making with the ailerons. which allows the tail to follow the line of the turn instead of the tail being dragged through the turn. it will make for quicker, smoother turns.

also is the corsair motor and gearbox the same as the p-51d's?
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Old Jul 13, 2011, 06:53 PM
Looking4Grass in AZ
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United States, AZ, Mesa
Joined Feb 2011
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I like doing rudder turns with slight opposite aileron so that the wing is freakishly flat. Looks neat. I learned to do it while flying on the prop with a UM 4-Site in a much too small area where on-wing-flying would just been banked at all times and scary. So I was high alpha at all times instead. I was more comfortable turning flat and staying in high alpha than banking and yanking. I have a taileron plane for bank and yank.

Yes, the P-51D uses the same motor as the F4U.

The F4U that I have right now was assembled by me and I didn't use a lot of glue. However, I used a lot less glue on the motor mount than Horizon does. I used a light glue, they use piles of silicone. So mine may have been tail heavy from the factory, and my rebuild may be "nose-light". I'll have to take a look at CG sometime when I have the manual and the plane in the same place. I'd like to use as little ballast as possible and have it as far forward and close to the center of the fuse as possible. A dime under the nose might fix CG fore-aft, but top-bottom is guaranteed to be horribly balanced after.

I will:
~Check CG with dime fore/aft like people usually check
~Check CG with dime up/down to try to explain bad inverted performance
~Remove dime, check CG both ways
~Add lead shot to the nose of the fuse with tape to get CG correct
~Glue lead shot into the fuse at the nose

I don't have any loading supplies out here, so I'll have to take a razor to a shotshell.
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Old Jul 13, 2011, 09:23 PM
Gopher huntin' stick jockey
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East Bethel, MN USA
Joined Jul 2009
12,142 Posts
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Originally Posted by wab25 View Post
Your statement in bold confuses me a bit. Being that the complaint is that the stock prop does not have enough thrust, wouldn't it be even harder to fly on the prop instead?
Wab,

The primary complaint is that the stock prop is too slow. Sure, the stock prop is also down on thrust, but the lack of airspeed is the root-cause of the handling problems. The stock UM F4U is simply not fast enough to get the airframe more than just barely 'up on the wing'. In the case we were discussing (level inverted flight), it is the low airspeed that is causing the plane to fly so 'heavy on the sticks'. Bump the airspeed up by 5-10 MPH, and the problem disappears. Adding more nose-weight than what is required simply increases the stall-speed & increases the amount of elevator trim needed for level flight - which increases the induced drag. This exacerbates the problem.

Joel
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Old Jul 14, 2011, 04:24 AM
Looking4Grass in AZ
Afraidtoregister's Avatar
United States, AZ, Mesa
Joined Feb 2011
1,357 Posts
CG is factory correct with a dime. Imagine that. It's like 31-32mm without it.

Oh, and this is by mounting my battery farther forward than there is velcro to hold it. So I'll be adding shot near center to get it right so CG will be correct for rolls and it won't roll like a harley crankshaft.
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Old Jul 14, 2011, 10:28 AM
AMA 1042906
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United States, KS, Derby
Joined Mar 2008
1,155 Posts
Quote:
Originally Posted by Afraidtoregister View Post
CG is factory correct with a dime. Imagine that. It's like 31-32mm without it.

Oh, and this is by mounting my battery farther forward than there is velcro to hold it. So I'll be adding shot near center to get it right so CG will be correct for rolls and it won't roll like a harley crankshaft.
Rather than add useless weight buy some Hyperion 240 1S batteries. The weight is 7 grams and corrects the CG if the battery is put as far forward in the stock battery slot as you can. The slot has to be made somewhat larger but it is an easy modification. I'm also using a 5043 GWS prop. My CG is 27mm.

Allan
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Old Jul 14, 2011, 10:48 AM
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Sausalito Marin Cty, California, United States
Joined Aug 2004
892 Posts
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Originally Posted by turboparker View Post
Wab,

The primary complaint is that the stock prop is too slow. Sure, the stock prop is also down on thrust, but the lack of airspeed is the root-cause of the handling problems. The stock UM F4U is simply not fast enough to get the airframe more than just barely 'up on the wing'.
First, that has not been my experience with the plane. However, lets say that is entirely true, the stock prop is too slow and is down on thrust, so much so that the airframe can barely get up on the wing. If that is the case, then flying it on the prop will only be worse. You need a lot more prop if you are going to fly on the prop, then you need if you are going to fly on the wing. By raising the nose, the prop now has two jobs, go forward and keep plane up. This means the prop will provide less forward pull. That right there will cut your airspeed. On top of that, the entire plane is now causing drag, slowing it even further, losing even more lift from the wings. Having a prop that is too slow and not enough thrust means that it is much more import to fly on the wing. Gliders fly on their wing just fine, many have no prop to worry about.
Quote:
Originally Posted by turboparker View Post
In the case we were discussing (level inverted flight), it is the low airspeed that is causing the plane to fly so 'heavy on the sticks'. Bump the airspeed up by 5-10 MPH, and the problem disappears. Adding more nose-weight than what is required simply increases the stall-speed & increases the amount of elevator trim needed for level flight - which increases the induced drag. This exacerbates the problem.

Joel
This is why I object to people adding weight without knowing the CG or where it should be. Also, there are more ways to bump airspeed than simply adding more prop. Having your plane fly in the right attitude will add significant airspeed.
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Old Jul 14, 2011, 11:16 AM
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Joined Nov 2004
857 Posts
For years I flew the prop on underpowered planes. I finally figured out a touch of downtrim made most of the delicacy in handling go away, as this kept the aircraft in the right flying attitude and kept airspeed up.

I haven't had real issues with this bird. Mine flew fine on the stock prop. I poked a hole in the back side of the cowl to move the CG a touch further up for more wind handling but, it was ok stock forward position.

With the 5043 on there now, the bird rolls like a power drill, has tons more control authority and does all the expected warbird aero easily. I can choose to fly the prop or the wing, with power to spare to pull out of any situation.
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Old Jul 14, 2011, 05:21 PM
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Canada, QC, Saint-Hubert
Joined May 2011
108 Posts
Strange problem today,

I just put a new 5043 and was having a blast with the plane, first battery was awesome. I did not wait and put on a second battery and after 3 mins of flight I lost control and then just got it again, I was not really far out maybe 50 feets. So I changed the remote's battery (stock controller here) and gave the plane a fresh battery... Same thing ! now when it's in my hand the servos move strange. Went back home, tried it again and everything looks fine servos are fast and smooth.

What could be the problem ? Don't tell me to get a real controller, it's already on the way.
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Old Jul 14, 2011, 05:32 PM
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Joined Jul 2011
118 Posts
I am a newbie here, but I do wonder if some of the trouble people are having with the Corsair has to do with their transmitter.

I see "porpoising" with my Corsair, but it may have more to do with over-controlling the elevator than with improper balance. I know that some people are running reduced rate or expo on the elevator, but I am using the transmitter from my RTF T-28, so dual rate is all or nothing.

Also, comparing the Corsair to the T-28, the way the elevator is constructed is different. In the Corsair, the connection between the 2 sides of the elevator is very flexible. What effect might that have?


I'm certainly not saying that none of the Corsairs are out of balance, but mine flew pretty well out of the box. Mostly what it lacks is pilot skill


Also, I have made several repairs on my Corsair now, and the weight of this little plane is increasing with every repair. That can't be good.


So, I am thinking of getting a DX6i. Will that help me be a better pilot?

I have a feeling the programmable rates and expo will be very useful, especially on the Corsair. Isn't is also possible to mix elevator with the throttle to help make it easier to maintain level flight?
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Old Jul 14, 2011, 05:33 PM
Flyin' low & slow T-28s!
MaladroitFL's Avatar
United States, FL, Vero Beach
Joined Feb 2011
3,324 Posts
Quote:
Originally Posted by Mespert View Post
Strange problem today,

I just put a new 5043 and was having a blast with the plane, first battery was awesome. I did not wait and put on a second battery and after 3 mins of flight I lost control and then just got it again, I was not really far out maybe 50 feets. So I changed the remote's battery (stock controller here) and gave the plane a fresh battery... Same thing ! now when it's in my hand the servos move strange. Went back home, tried it again and everything looks fine servos are fast and smooth.

What could be the problem ? Don't tell me to get a real controller, it's already on the way.
You're not supposed to be flying in Quebec in mid-July. You're supposed to be getting ready for Just For Laughs Fest and the influx of comedians and tourists.
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Old Jul 14, 2011, 05:46 PM
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Mespert's Avatar
Canada, QC, Saint-Hubert
Joined May 2011
108 Posts
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Originally Posted by MaladroitFL View Post
You're not supposed to be flying in Quebec in mid-July. You're supposed to be getting ready for Just For Laughs Fest and the influx of comedians and tourists.
I won't go to Montreal because the bridges will fall, the tunnel will collapse and the metro is hot and overcrowded. I stick to the south shore of the island!


So anyone has an idea ? I have 2 RTF controllers I'll go back to flying tonight and test both of them, but can it be possible that when the electronics gets hot they works strange ? Never hapenned to my trusty T-28 tough.
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Last edited by Mespert; Jul 14, 2011 at 06:09 PM.
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Old Jul 14, 2011, 09:17 PM
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Mespert's Avatar
Canada, QC, Saint-Hubert
Joined May 2011
108 Posts
I got the solution, I bound the same transmitter again and was able to get trough 7 batteries without any problems.

I would like to thank Turboparker for all his help, now my F4U has a 5043 prop and adapter, I learned what is to fly on the prop and on the wing, and what is tail heavy.

Thank you, now this plane is awesome !
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Old Jul 14, 2011, 09:21 PM
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United States, CT, Glastonbury Center
Joined May 2007
1,441 Posts
Quote:
Originally Posted by random13 View Post
So, I am thinking of getting a DX6i. Will that help me be a better pilot?

I have a feeling the programmable rates and expo will be very useful, especially on the Corsair. Isn't is also possible to mix elevator with the throttle to help make it easier to maintain level flight?
a DX6i won't technically make you a better pilot, BUT you will have a LOT more control and range compared to the plastic RTF TX.

I just recent got a DX7, I'd been flying 3-channel ultra micros for a few years and the DX7 was by far the best purchase I ever made. I am mad that I waited so long to get a real TX. Get one ASAP, trust me - you will LOVE it.
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Old Jul 14, 2011, 09:36 PM
No Guts, No Glory!
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USA, WA, South Hill
Joined Sep 2008
3,219 Posts
Keith, I gotta say, I am one of those D.A.M. happy converts out here!

I've had my Corsair since its release and I have many (many) flights on her... was never totally sold on the flight characteristics of her though, but I was able to fly her fairly steady until this eve...she's too cool lookin' NOT to fly ... but now she flys D.A.M. good!

hey, I don't get it, I thought she balanced pretty well at the 30-31mm with landing gear, but using some dbl sided tape I stuck a dime as far forward under her cowl and she's right about dead on the 28mm mark and best of all shes fly's like I'd hoped she could... daaaang, a HUGE difference in steady & smooth!! enough so that I moved all my control horns to max and tweaked my dual rates a little and hoooly moly, on high rates she rolls like I never thought she could/would

anyways... thanks for the idea!







Quote:
Originally Posted by MaladroitFL View Post
It makes me feel good to know that my Dime Adjustment Method DAM (ha ha!) has helped so many.

It was really just a whim, but I was going through the same ordeal as you, Afraidtoregister. It was kind of a last ditch thing before I gave-up on it and shelved it for good.

For those who missed it....
http://www.youtube.com/watch?v=09xAEQKt4EQ
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