nemesis4u

My Feedback: (77)

YARDDART,,, YOUR SIERRA GEAR should be there any day now!!!! http://www.vqwarbirds.com/products/a...RACORSAIR.html

....

IN other great news.... the CORSAIR COCKPITS will be available in 9 days!!!

Here are the online assembly videos... makes assembly a breeze compared to what you get with other cockpit kits...

http://www.youtube.com/watch?v=xuxSmU0lmfE

http://www.youtube.com/watch?v=kq9vPmcK_w8

IF you wanna go ahead and get on the list now... just email me at: [email protected]

-CHEERS!

TOMAS
VQ WARBIRDS
"KEEP "EM FLYING"

lynn1130

My Feedback: (10)

WARNING-WARNING-WARNING

DO NOT BALANCE THIS PLANE AT 130 MM. IT IS WAY TOO FAR BACK.

I was all set to fly this morning and had the help of a very experienced war bird pilot/builder who was to help with the maiden flight. We spent some more time getting the engine tuned up and taxied the plane around. We range checked and then he wanted to double check the balance. It was at 130mm. We used the old index finger trick with him picking the spot that he thought it should balance. Well-it was WAY tail heavy. By the time that we were done, he had called 5 more very experience war bird builders/fliers over and each, to a man, picked a balance point forward of KMP's recommendation. Needless to say we did not fly the plane today.

The suggested balance point is NO LESS THAN 3 INCHES and NO MORE THAN 4 INCHES BACK OF THE LEADING EDGE.

You all can do want you want but I am balancing at 3 to 3.5 for the first flight.

Ompa

Hi lynn1130. This was a very interesting thing you brought up here. My manual says balance the plane at 110mm from leading edge. Looking forward to here from your maiden

Craig-RCU

Wow, with all the capital letters and bold text I'd have thought that you'd actually flown and crashed the plane to confirm that 130 mm is unflyably tail heavy. Did someone have a bad case of first flight jitters and was looking for an excuse not to fly?

johnnyjet

My Feedback: (4)

Good save lynn1130.
Thanks for the information, no telling how many planes you just saved.

Johnny

LDM

My Feedback: (15)

Lynn , how does that compare to the 25% of max ???
Thanks
Lou

lynn1130

My Feedback: (10)

I am not smart enough to understand all of that but if you figure 25% of the wing root it comes out to 3.87 inches. That would jive with what the experts were saying this morning. 3 inches and not over 4.

Now, again I have never understood, totally, those calculations, mainly because I just used the manuals recommendations. But now I need to learn because you CANNOT trust what KMP has in theirs.

Last week one of the guys did major damage to his KMP P-51 because he used the manual recommendation. It was so tail heavy once airborne that they had a hell of a time getting it back on the ground. That is what caused the specific, close look at mine today. It would also explain all of the problems that I have had with the Spitfire. It is a handful but is set to KMPs recommendations. I am going to change that at a later date.

I can tell you that this is going to take major lead up front to get it balanced.

Interestingly, one of the comments that was made this morning was that if the plane leaps into the air it is likely tail heavy. Yard-dart had just that problem and I have seen videos on here of others doing the same thing.

VeeAte

Thanks for the info lynn1130. 

masteromodels

My Feedback: (11)

I used a G-38 in mine and it flys good. I added about 4 oz. of lead in the cowling and the plane handle just right. The G-38 gave the extra weight and power to boot.

VeeAte

Thanks masteromodels. 

masteromodels

My Feedback: (11)

Actualy I balanced it according to the manual . I just checked on the wing and the mark is still there . If you look at the bottom of the wing and use where the back of the raised portion is that is what I used. Actually I measures approx. 5 inches from the front. I know every one else is saying something different but that is where mine balances and like I said it flew with no problem other then the landing gear coming down and locking , I had to belly it in but I did not sustain any damage. I do not know where all these other measuments are coming from but the manual was right on mine. Sorry I cannot help you more.

thanks bob

masteromodels

My Feedback: (11)

here are a few shots of my KMP Corsair.

thanks bob

LDM

My Feedback: (15)

Bob nice panel lines , how did you do them ?

Lynn , the math needed for the 25% cg test is very very easy , there are ways to check it by I not smart enouth to show you in a digital drawing .
Explaning it is simple - cord is the measurement from the front wing to back , max cord is term used for the front to back at the largest part of the wing .
Typically most suggest taking this measurment at the wing connection to the fuse .
so if you measure the wing and its 12" in front to back you take 25% of that number =3" as your starting point for CG .
Now the "line method " and that is harder to explane but easy to do and draw -

lynn1130

My Feedback: (10)

Then my figure of 3.8 is correct. Where KMP comes up with 130 mm or about 5 inches I do not know. It may fly that way but it will fly much better at about 4.

103 mm, as in the new manual is much closer to where it should be that 130. My guess is that 130 is a Chinese misprint!!!!! Should have been 103

masteromodels

My Feedback: (11)

I used a combination of different color pencils and characoal sticks, then just spray with a flat clear to fuel proof. Here is another picture , you can see a little more detail. I did not go nuts with this kit because I'am working on a couple of other giant scale Corsair kits . I like the larger planes more.

thanks bob

LDM

My Feedback: (15)

Bob thanks for the details but no pic showed up

VeeAte

Thanks mm. This CG thing is quite the topic at the moment.
A search through the thread a few weeks ago had me certain that 130mm was correct.
I always maiden my planes a little nose heavy anyway and I have a habit of landing hot all the time as well so I dont think I will have a problem either way, but may set mine to 115mm and just slightly nose heavy. Cant get into too much trouble that way I guess.


Nice work on the Corsair Bob. I love the panel lines and rivet details you added.
I would like to see some more pictures as well.

All Day Dan

My Feedback: (5)

Maybe this will help. Dan.
http://www.geistware.com/rcmodeling/cg_calc.htm#mac

LDM

My Feedback: (15)

Dan thats the one , if you continue to draw line A and line B , then have connect the top end of A with the bottom end of B and then the do the same to the other side , you will get a big X , the x when the line meet to form the X that is another way of checking the CG

Ompa

Well, as i see it it looks like i most have one of the newer kits from ESM, thus to it says CG should be at 110mm.
Gonna check out the cord and use the CG calculator in Dan's post.

And Bob, really loves your panel lines. Nice work

lynn1130

My Feedback: (10)

Try this for dry transfer panel lines as well as other dry transfers.

http://aeroloft.com/

yard-dart

My Feedback: (35)

OK, here's the scoop guys. The 130mm CG is correct. When I flew mine the first time, it was tail heavy. I knew that before I flew it. That day, at 130mm with the gear "up" the tail dropped slightly (tail heavy). Put the gear "down" and the nose "barely", and I mean "barely" dropped. On take off, the plane didn't climb straight up, but it definately didn't have any problem coming off the ground.
With all this being said, I finally got around to flying mine again yesterday, with nose weight. I added 12.oz of lead to the firewall. At the suggested CG of 130mm, with the gear in the up position, the plane dropped the nose enough to make me happy. Gear down, it dropped it even more. I felt comfortable with what I was seeing. At the field, the plane flew great. I stayed on the runway until I pulled it off. I actually had to pull back on the elevator to to get it to pull through the turns, unlike before when it would hook just by looking at the stick. So, what I'm saying is that I feel quite sure that the suggested CG is correct, it just takes a ton of weight up front to get it to ballance. Guys, the wing is a brick! If you look at how much weight is aft of the CG on just the wing alone, that'll give you a wake up call. Before I ever mounted my engine, I had the plane setting on the gear under my carport. Again, no engine, no cowl. Just picking the tail up on the tail cone shocked the hell out of me. It felt like I was picking up a gallon of milk! I knew right then that my engine and ignition system alone wasn't going to balance it out. It's the wing that does it. It's solid, but it's heavy.
On the final leg before landing, when I dropped my flaps, the plane's attitude never changed. It didn't climb/balloon up, and it didn't drop the nose. It stayed rock solid. I could tell the flaps were doing their job of slowing down the plane. It floated in perfectly. I took off again made a loop and came back in with flaps up. It came in a little warm as expected, but still rock solid.

Get your balance right, and do it at the suggested CG, and the plane will fly great. Mine did.

LDM

My Feedback: (15)

Yd ,
so you saying that 130 mm is good , just get it to balance at that Cg .
Also are you saying the elevators are less sensitive at that CG ?
Please elaborate
Thanks
LDM
PS did you use the KMP retracts and did they work

yard-dart

My Feedback: (35)

Yes, the 130mm is good, without a doubt. Any plane is going to be touchy on elevator if tail heavy. Mine went from being extremely sensitive on elevator from being tail heavy to being dead on just by me adding nose weight. That's the only change I made, adding nose weight. I knew it would cure the problem.
I did use the ESM retracts. The quality was good IMHO. I shimmed them so there wasn't so much slop in them when in the down position. The only problem I had was by me not using loctite on one of the internal set screws. I used loctite on both of the struts but didnt' use it on a set screw which is located in the mesh of two dears that rotate the struts. The set screw came loose and I lost my right strut. The funny thing about it was that under normal circumstances, a strut comes off because flat spots aren't put on the stud the strut slides upon and loctite isn't used. I did both, put flat spots on the stud, and used loctite on the set screws. But..... I still lost my strut because the little set screw in the little gear the stud slides up in came loose. When the strut departed from the plane, the stud was still in the strut. Other than that, I felt comfortable with the gear.

With that being said, I got a set of Sierras to replace them because there weren't any ESM's in stock to replace my lost one. The Sierras are NICE! Everything comes tight from the factory. I checked all bolts and set screws and they were all tight right out of the package. No midifications were needed on the Sierras.

yard-dart

My Feedback: (35)

Here's a couple of links to pics of my gear after I lost my strut.

http://i249.photobucket.com/albums/g...5/100_4087.jpg

http://i249.photobucket.com/albums/g...5/100_4080.jpg

http://i249.photobucket.com/albums/g...5/100_4082.jpg