Corsair 60 Looking for Nose Weight Suggestions.
 

I think some of you have some genius methods for balancing models. I'm trying to balance my corsair 60. My battery pack (5 cell 6 volt 2000 mah NiMH) is as far forward as possible. I currently have both the Harry Higley safety propeller lock nuts and a brass spinner nut. I'm undecided on what propeller I'm going to be using but I have a 13x8 three bladed, 14x7 three bladed, 13x8 two bladed, and a 14x6 two bladed. Right now my goal is to get my plane balanced for either of the 2 bladed propellers. This means that whatever weight I add will need to be made removable, just in case at some point in time I want to try any of the 3 bladed ones. Currently the model balances with the 14x7 three bladed. The Engine I'm using is a .75 OS AX. The airplane is tail heavy.

When you balanced this airplane. How did you mount your weights in the nose? If you have any photos, that would be great too!

I'm using the great planes CG machine. I'm Balancing the Airplane upside down, and the retracts are retracted. The Propellers are all master airscrew nylon propellers.

Link to Model Kit: http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXHU80&P=ML

I haven't had that particular airplane, but there really aren't many tricks to be known about adding nose weight. Find the farthest forward hard point, and add lead to it until the plane balances. I've seen people even epoxy lead into the front of the cowl in cases when the cowl was strong enough to handle the extra stress. But the engine mount is the usual place.

Well here are a couple more tricks: The first picture is my Sixty sized ARF Corsair with a ninety one fourstroke and the other a ninety sized Hellcat ARF with a 1.08 OS.

The Corsair balanced with no lead with both batteries mounted all the way forward on simple fabricated selves screwed and epoxied direct to the firewall. Mounting lead on cowls is an exceedingly poor idea as mentioned you never be able to keep screw in the cowl and even in hard landing breaking off the screw blocks all together.

The Hell cat shows a combination of one battery tray and a lead box mounted directly to the firewall.

John

http://www.rcuniverse.com/forum/atta...mentid=2109090 http://www.rcuniverse.com/forum/atta...mentid=2109092 http://www.rcuniverse.com/forum/atta...mentid=2109093

I forgot to mention that my engine is mounted 45 degree angle inverted.

I hope you put foam around your batteries! (I worry about vibration breaking solder joints on the Batteries, and leads. Also all the oil getting on those things!) Do you wrap them in plastic?

I will show your pictures to my dad and see what He thinks. Thank you for the Idea and pictures.

Hi Greg There is a thin foam layer between the tray and the battery and this type of setup has never been a problem nor is heating of the batterIes which if done right they actually run cooler a few degrees. Since I first used this on airplane that needed it (mostly round cowl warbirds) battery heating was argument aginst it But after I got my first Hitec Aurora 9 and shortly after got their first full telemetry system I was able to compare two similar airplanes with the same engines, one with the above setup and one with a typical buried foam wrapped battery. the The buried pack ran a few degrees hotter consistently. I preferred my batterys to run cool.

As far as oil goes yes they can get a little oil and no I do not wrap. It has never proved to be a problem. I gotta head for the field this AM but will post a few more pics of other airplanes with this if you like.

John

Thank you for the information.

Photos and Videos are always welcomed!

I took my wings and cowl off. I'm looking to see if It is possible to mount my battery on the firewall. It's a bit iffy for me, because I don't have much room there. It appears to me, that the reasons you have room is because of the way you have your cowl mounting blocks, and with the 4 stroke your muffler isn't inside the cowl. *I was trying to take some photos for you. I might try again a little later.

I hope you have a good day flying! I was out with my Zlin 526 today. It was a blast of fun. Too bad they discontinued the ARF kit: http://www.greatplanes.com/discontinued/gpma1024.html

This photos are not as good as I wish they were. But they are the best I know how to do. I'm just trying to show why I think I might not have enough room for the Battery on the firewall. If I mount it the other way (Just not sure how I can attach it to the firewall) I think John's plane has more room because His muffler isn't inside the Cowling. Nor is it mounted to the firewall. If someone here can show me a way of doing it, I'll try it.

http://i1089.photobucket.com/albums/...psxk3r8qy7.jpg


http://i1089.photobucket.com/albums/...ps1yemhntm.jpg

http://i1089.photobucket.com/albums/...psyek2hmth.jpg

I would not mount the batteries on the firewall or engine. I have had 2 of those hydrimax batteries fail because the tabs were poorly welded, fortunately they were being used for ignition batteries. You can mount a large lead weight to the engine mount like I did here http://www.rcuniverse.com/forum/atta...mentid=2109173 you can see the battery that later failed on top of the engine. I buy large fishing weights then melt them down outdoors ( avoid breathing lead fumes) and pour into small metal cups to make a big weight..

Right after reading this, I tried to put the battery back inside and found out that I have a bad connection some where. I took the battery back out and hooked it up to a volt meter. The Battery seems fine. But so does the radio end (on a different battery) (shrugs) Just more work I got to do.

* Every time I think I got one thing figured out another issue comes up.

Hey Greg, my apologies in being late getting back. I promised some of the ships that I have used successfully for both forward battery packs as well a forward weight boxes.





http://www.rcuniverse.com/forum/atta...mentid=2109429 http://www.rcuniverse.com/forum/atta...mentid=2109430 http://www.rcuniverse.com/forum/atta...mentid=2109431 http://www.rcuniverse.com/forum/atta...mentid=2109432


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Hey Greg in answer to your question you asked this morning I am back from the field now and weighed my sixty size Corsair and it weights 10 pounds and 1.6 ounces. I did sometime back remove the Fourstroke and installed an OS 1.08 two stroke but still use the Sullivan glow lighter and the two packs in the same position. The 1.08 does perform a little better but more important ideling and throttling is far better for the arrested landings.

Someone complained about the Hydrimax batteries being unreliable. I can,t really address that as I only have around five of their 2000's and for me they have been reliable, that's over maybe perhaps three or four years. My go to 2000 that I tend to by in bulk is the Tenergy That I pickup from the LHS. Its the one on top in the picture.

http://www.rcuniverse.com/forum/atta...mentid=2109522

John:cool:

John thank you for taking time to show me pictures. Your input is helpful. :)

I tend to do about the same thing as John and over the years I have only been using a bit of foam for a cushion, more to keep the packs snug then about vibration. I really haven't had any problems with the packs leads breaking but these days I have my packs made up for me at Batteries Plus so the welds are done very well, not mass produced.
I have also used the weight box like John makes up. It's a good system for adding and subtracting weight to dial in the CG or for when changes are made.

Maybe a couple small shims behind the mount will shift your weight enough to balance . ENJOY !!! RED

I have a bad muffler set up for that. Because the muffler used is screwed into the firewall with wood screws. I would need to either glue in some spacer blocks or somehow extend the connection tube to the muffler.

Guys there are a lot of things on this plane that is driving me nuts. My Dad and I tried to follow the instruction book and plans to the best of our ability. We only made changes where our experience taught us that things needed to be done different. And yet issues just keep showing themselves. Things have been so bad that we go to work on the plane early in the morning 7:00AM or 8:00AM and work on it until 4:00PM. (Only taking a break to eat) No sooner do we think we got everything fixed, and we go out to taxi or the plane, or just run the engine, and something else comes up. It's been like this all Summer long. We think that if we can't get the plane in the air by this week or next we're going to quit and try again next year! I own 6 different airplanes, some were kits and some are ARF. I've flown R/C since 1995, and I've never had an airplane give me as many issues as this one has. We've put our heads together and tried to tally up the choices we made verses the things the instructions told us to do. It comes down to lack of experience, and an instruction manual that is not written good enough, for people like us. Every plane we have ever built, had something on it that is new to us. But this plane has several things that are new to us, and they never tell you should do about it. I don't know how any of you guys got the experience/information that you got. Maybe you had enough people at your flying field inform you of these issues pryer to starting the project. I'm thinking about writing a blog about this airplane, pointing out all the different things I think the manual should of told me and didn't. There is a good chance that if for some reason I can't ever get this plane to fly, I don't think I'm going to build another one. I don't think I'll even get the ARF version. I'll just get something else.

* Been at this project for 4 years.