Larry S

My Feedback: (6)

cathurga, take both Zeno and my word, it flies great. It's been a while since I posted on here and over time many horror stories have been told about this plane. There isn't a thing on this plane that isn't hard to change for the better. Someone else had asked about the CMP 50 Corsair and wanted to know what should be done to make it a better plane to fly. What I did was write out everything I did to mine that I know was worth the time. IF anyone wants to know the changes I made, I'll post it. Easy to copy and print. I just don't want to put the same things in different posts, takes up space and can be a pain in the butt to those reading them. If somebody really wants to know, I'll post them.
Larry

cathurga

Larry, I am keen to know, and sharing info is what the forums are all about right...post away buddy!

Larry S

My Feedback: (6)

Before I post the changes I made, you might want to think about this in trying to decide if the modifications are worth the time and trouble. Late last year, I was fooling around, doing touch and goes, etc when on one take off, it snapped in, my fault. The plane went in nose first breaking a nylon prop and knocked off the wing. Damage to plane: wing, none. Fuselage including cowl, scratched all to hell, simple fix with airbrush. The skin had small cracks, more like fractures and I fill them in with micro ballons. The paint I mixed looked close but went on darker then I wanted but after looking the bird over, it looks cool. It looks weathered like a war bird should. All formers including the firewall held up. No wood parts were broke. IF I hadn't done the extra work, I would be buying a new plane. So here goes.

Changes I did to CMP 50 Corsair:

Coarse sand complete inside of cowl. Mount dummy engine on 1/16 ply and using heavy fiberglass material, epoxy dummy engine in cowl. I found it was easier to insert dummy engine exactly where I wanted it then applying three or four drops of thigh CA and use an accelerator to hold it in place until the epoxy sets. I used the fiberglass material and epoxy on the joint between the dummy engine and sides of cowl and turned the cowl on it’s nose to let any excess epoxy run into the nose of the cowl. Use strips of cloth and overlap each one. Epoxy that ran into front ( nose ) will strengthen that area. Noseovers won’t break the cowl as easily. After that sets, use 3/4 glass cloth and do the complete inside of the cowl being careful not to get any epoxy on the painted surface. Now you have a strong cowl. Where ever your screws will go through to hold the cowl add one more one inch squares of 3/4 glass cloth to build up that area. I also first screwed the ply ring onto the fuse that holds the cowling. After I was satisfied on the location, I took it off, added epoxy on the inside of the ring and screwed it back on. Forget about the added extra weight at this time.
I made my own mounts from a better grade of ply for the landing gears. I had first installed RhomAir retracts but they gave me problems so I decide to go with a fixed gear. I didn’t trust the ply I got with the kit, that is why I used my own and I epoxied everything in.
Inside of the plane: sand as best as you can and add epoxy to all the formers. I even bent an epoxy brush backwards to get to the opposite side of the formers. Between the formers and skin, that is a weak area that will come loose over time. Not anymore.
Firewall: Add epoxy and cloth between the firewall and fuselage where ever you can get it. That is one area that seems to never be as strong as it should be from an ARF. One important thing I found with my Corsair, plans show 2 degrees down and 2 degrees right thrust. I found that my Corsair had the right thrust built in but no down thrust, so I made a shim to put behind the motor mount to off set that thrust. Don’t fly it until you have both right and down thrust.
Again using a bent epoxy brush, fuel proof all wood inside from the servo tray to the fire wall of fuselage. That also helps keep the glue they used from coming loose. Lot’s of weight, but useable weight, you’ll see.
Canopy: I screwed mine on but first epoxied blocks of hard wood to the inside of fuse at the points where the screws would go through.
Control surfaces: I use only epoxy, no CA on hinge areas. I’m not sold on CA for that.
Servos: mount them as far forward as possible.
Engine: I first tried an OS 46 FX and it was marginal. If our grass field had just been mowed, no problems but if the grass was high, then the 46 would need a lot of runway to lift the plane off. I ended up going with an OS 61. That engine does the job, gets the plane rolling at a good speed before lift off then I just throttle back to where I like to fly. Make sure you have your airspeed up before lift off and when it comes time to lift the plane off, it will probably go up by itself if trims are set very good. But if the trims are not set the first time, which they probably won’t be, don’t force the plane up. After the plane is rolling, EASE back on the elevator till the planes lifts then hold it there until the plane reaches the altitude you want. Gently let it climb, no hard turns. Once the plane reaches speed, then you can do what you want, you’ll have altitude to work with. One thing, none of my Corsairs will do is a stalled, snap roll. I have crashed more Corsairs then you would want to know and every time, the same way.
CG: On the CMP Corsair, the shown CG is close, but no cigar. You can fly it that way and I did on my first flights but you’ll have your hands full. I used a CG of exactly 3 inches from the leading edge, spaced 15 inches apart using a Great Planes balance machine. This is a little less then the 80mm to 85mm shown in the plans. That means the plane has to be a little more nose heavy to balance and remember all that epoxy you added in the cowl, it now has become your friend. I still had to add some lead weight, but not as much if I hadn’t reinforced the cowling.
Guns: Airbrush out the decal guns on the plane and install 1/8 brass tubes where the guns should be, outside the gull.
Remember, these are changes I made based on my having two of these planes, one of which is no longer with me.

IronCross

OK you Corsair experts Learned something new concerning the white lines interesting... Now if I may, what is with the arrows.... One on the rudder would seem to say "this side up" and the one on the wing "fly in this direction" ?....

bassfisher

My Feedback: (21)

Just my 2 cents. The Arrows on the Tail point Up. They were Squadron markings. The white lines that so many Corsair have on them in front of the cockpit were origianlly used to stop leaking fuel from the Forward Fuse Fuel Tank.

Hisham

Hi guys
could you please post a link for the retracts your talking about for this model.
thanks
Hisham

cathurga

Hey guys,

My plane has finally arrived, so I am going to start on it as soon as I can. Having a look at the finish, I am definately going to start by giving it a coat of clearkote, this finish will get trashe VERY quickly, and I am not too perturbed about the additional weight, I am putting in the OS 91 surpass, so the weight shoulnit be a nightmare.
With regards to the cowl, I see your points about it not having enough 'strenght' so I will look at the glassing option, I am not a skilled glasser, nor do I have the place to do it so will have to consider that carefully.
The engine is going to be mounted at 90 deg, I would like to have had it at invert, but the carb will sit WAY lower than the tank so flooding could be a problem. I would have preferred inverted so that any cutting of the cowl could be kept to a minimum. Also the exhaust is going to be a problem. I have an OS flexi pipe that I might route outside the cowl and along the belly pan, it should also help to keep the exhaust splatter away from everything.
Another consideration I have is to get 4 pieces of ply, about 5-6mm in thickness, bolt and epoxy that to the font of the fuse, and mount the cowl ring onto that. Get another square of ply the same thickness, bore a hole through it and mount the engine on to that, this will do two things, A) allow me to shift the weight of the engine forward, and B) allow space for the escaping air to get out without cutting up the canopy, any thoughts on that? Having looked at the setup, it may require that I cut open some of the cowl flaps in order to give more breathing space, but thisi is more acceptable than chopping holes in the cowl...

Will keep you up to date on the progress....

Larry S

My Feedback: (6)

Glassing the cowl is easy, just try not to make a mess on the outside of the cowl. I would recommend glassing the cowl before doing any cutting. The way I did mine was I cut small pieces of 3/4 glass cloth and fit them around the inside of the dummy engine. Remember, this is all done on the inside. Then for the sides I used a heavier glass cloth and cut them into strips. I found it is easier to do small sections then try to do the complete cowl all at once. Just keep some alcohol near by to wipe off epoxy you may get on the outside of the cowl. I used a 30 minute epoxy not thinned down. I would spread a layer down then put my cloth over that and then spread more epoxy until the cloth was covered. Around the inside of the dummy engine you'll be surprised how easy it is to get your cloth to bend and lay flat on the plastic, even with all those curves and bumbs. Just use several small pieces and make sure you over lay them.
I am using a OS 61 in my Corsair and I have it inverted and have had no problems with flooding. On this plane I use a modified J Tec muffler and it works good. There are other mufflers you could use but the J Tec fits tighter in the cowl then others I have looked at. Nice thing I like is I have an opening in the front of the cowl for carb clearence and I have the bottom cut out for engine and muffler clearence and cooling and it's easier to get to your glow plug.
AS for moving your engine forward, I think you'll screw up the looks of the plane. Sounds like a good idea but I don't think you'll like the looks after you're done. I sent a picture of what I did to mine, might give you an idea on how to do yours.
Larry

cathurga

Larry,

I get you, I am defo going to try the glassing. The cowl is decidedly weak...

I forgot to mention that my engine is the four-stroke, so It WILL protrude out the cowl. WRT moving the cowl forward, it is only going to be a few mm's, and won't be that noticable....I think. I will do the excercise without epoxy so that if it looks bad, I will just remove the additional ply that I use and restore it back to normal.

Thanks for all the advice!

Larry S

My Feedback: (6)

Just take your time with this bird and think each modification out. For what's it worth and maybe others will add to this, using a 4 stroke makes the plane a little harder to fly simply because you then will have additional torque to deal with, so be careful. I have some warbirds with 2 stroke and some with 4 stroke engines and with the ones with the 4 stroke engines I have to use better throttle control. IF you're coming in a little short of the runway, gently give it throttle and be ready for the plane to start to roll on you at low speeds.
Larry

erec11

Hello virtualvictum i need to ask you this have you cut some of the cowl bacause of the head of the engine? i´m starting to build my CMP Corsair but i´m not buy the engine so far, i´m still asking for opinions abaut it. Should i buy the OS 55 AX or the OS 61 FX???? i dindt want to cut any part of the cowl! i will put the engine over is right with a Pitts muffler just like you did in yours, i´m flying in a military airfield because i´m a military and its all pavement so i will not need much power to get it airborn right?? i with love if you post some pictures ( the interior ) of yours because i have see thys guys puting the receiver batteries over the engine because the plane is tail heavy! i will also put this oleo struts from VQ but i still think that the wheals are to small is there any way to put a large ones with another wheels cup? i hope you could help this new pilot. tanks

Scott Douglas

Well, after a week of working on it in the evenings, here she is......

I did strengthen the cowl with some toilet tissue soaked in superglue and added my own u/c mounts but other than that its pretty much stock. I'll test fly with fixed u/c and add retracts when time allows

Regards
Scott

Hisham

good luck on ur test flight,
keep us updated ...
Hisham

erec11

Hello Scott Douglas can you put some pictures of the inside of your Corsair, I´m starting mine now, it would help. Tanks

Scott Douglas

Erec11

I will post some for you tomorrow. If you have the version with the carbon fibre control rods be careful when you tighten the grub screws on the inserts, the thread gets chewed up too easily [:@] I know this from experience!!


Hisham, thanks! I'll let you know how it goes. It's too wet here today for flying []


Regards
Scott

erec11

Scott Douglas

Yes i have that with carbon rods but i will not use them, i will use standard 4x950 rods like in my Mustang, then i just cut what i didn´t need, i´m doing some modification on the engine mount to have some mor streng in there. I´m using a peace of wood 5mm epoxy on the fuse and then put the engine mount there. I will also use the idea of cathurga "get 4 pieces of ply, about 5-6mm in thickness, bolt and epoxy that to the font of the fuse, and mount the cowl ring onto that (...) A) allow me to shift the weight of the engine forward, and B) allow space for the escaping air to get out without cutting up the canopy" that may work just fine. The real problem that i have now is the engine: i was thinking of buying this OS61 but then talking with some guys i order this MVVS 61 - a great engine they say - but the engine has a 84 mm from the mounting base to the top, and i have only 84,5mm from the center line of the engine mount to the cowl.........!!! I didnt want to cut the coul but i think that i would have to! Its too tight. i mount the engine over his rigth with a Pitts muffler.

Scott Douglas

Hi Erec11

I've added a photo of the interior to my post above. I havent really changed anything in there apart from the rudder contol rod, the carbon one supplied was of a poor quality.

This is my second CMPRO Corsair, I had its bigger brother up until last year..... it died after the switch failed on me [:@]

Regards
Scott

erec11

Big problem!!!! I have you bend the tail gear??? Its not easy i tink because it must be bended after i put in place. Tell me how have you donne. I gonna send back the MVVS 61, its too big in the head and i dont whant to cut the cowl , i gonna for the OS 55AX its a nice engine and i hope it put this bird flying.

Scott Douglas

I had a pliers small enough to get in and bend it to shape...not an easy job but I got there in the end.

I've been working pretty much non-stop for a while and havent had time to fly anything, so I decided to spend some evenings adding some panel lines to the wings and adding some weathering.....

Regards
Scott

zeno

Great job on the weathering and detailing!

Did you find a blue paint thats similar to the one on the plane?

Scott Douglas

Hi Zeno,

I used Humbrol no.56 with a little black to darken it down a bit. Close enough for me

A few more pics....


Regards
Scott

patrick181

How do you do this type of panel line detail? Ruler and a silver paint marker?

Scott Douglas

Yeah I started off with a ruler and soft pencil for the panel lines. I used a small silver permenent paint pen for the paint chips (it's resistant to varnish).

My local art store sells graphite sticks which I used for the dirt effect, just using my finger to drag it across. Then I applied a coat of satin polyurethane varnish to seal it all.

regards
Scott

erec11

Hello Scott Douglas

I have this another problem: i have the engine mount in place i have the OS 61 with a Pitts muffler in plane but when i try to put the cowl in place....it dosent fit!!!! the carburator touch on the dummy engine!!!!

erec11

Any ideas on that?? i realy dont like to cut the dummy engine but..... buy the way could plese some one telme haw to put pictures in my reply.