Shupack,
Thaks for the info. Sounds like your on track for a good final weight. I'm using the CJ retracts also. Mounting was a real treat. Pete

I have the bird primed now, and am wet-sanding, but how much primer do I leave? do I sand most of it off to save weight, or do I just smooth it over? i have a few spots to fix, so i'm working on those first.

Has anyone added gear doors? If so, I'm looking for ideas.

I'm building the Corsair as my first.

Thanks for lots of great ideas and info.

Corsair as your first warbird, or first plane?

I would not suggest building a corsair as a first plane. Try a Sig LT-40 if you've never been around aeronautics, or a 4* if you have. Keep that corsair as a kit.

On to your question...

Juice and I are each working on gear doors. You can see progress for each of our planes in our picture galleries. You should be able to do a search for corsair gear doors and find a plethora of information.

It's actually my second. I did a right Flyer 60 and I am using that to learn to fly. I've got about 20 flights and only minor damage to the nose wheel mount.

I saw your gallery and would like to know about the spring that you use to open the door as the wheel is extending (gear bay detail photo). Is it a piece of thin spring steel?

Yes it is, although I scrapped that idea as the doors would not close. Right now I am using a string-based system as diagrammed in "landing gear doors" I am having trouble getting it to close completely, as my cylinders don't have enough oomph. I have a _old_ set of 615s - ones that have a plastic cylinder. Robart offers replacements, although I don't know if that will help.

I'm a spastic builder, so I am working on other parts of the plane, even though I have not solved that problem to my liking. I am currently working on the rear gear door, which I think is working better. I am using two short pieces of pull-pull wire attached to the landing gear.

I "aquired" a scale acurate to .1oz, and weighed all the pieces (i'm priming and sanding now) and added up, came to 6lb 7.5 oz minus engine, reciever, battery, and paint (some primer included) so i think i'm doing pretty good.

Stupack, I like the color scheme. Where can I get details?

all i have on it is the sqadron signal detail and scale book, but it has a few black and whites, a good 3 view and color drawings. i'm not going for scale-master, so i'm building to TLAR (that looks about right)

you can get the book here

http://www.historicaviation.com/hist...ks&category=ww

or if you just want details on the protype, i can scan and e-mail.

i'm pretty sure i've put all the necicary mods in the thread, the main two were moving the firewall back3/4", which meant the tail has to be extremely light, and moving the cockpit forward.

thanks for the lead. I'll buy the book.

Shupack:

Great mods! I just started mine a few weeks back and haven't had a lot of time to spend on it yet, I'll hopefully start the wings this week.
I really like what you did with the flaps and your location of the retracts gear. Can hardly wait to hear how she handles.
Keep up the good work and the pics!!!

BTW how do the CJs compair to Robarts, better, same, worse and how so?

thanks maiden,

i'm still priming and sanding, and re-priming and re-sanding to get her smooth. my CJ's are allright, not very scale looking, but better than fixed gear and cheaper than robarts. the struts are a bit sticky too, i think this is because there's no bushings, just metal on metal. there's a thread here somewhere in warbirds debating robart vs CJ for this bird specifically, have a read through that. i chose CJ's based on price and higher durability before i realized the craftsmanship is much lower, but i think they'll do for now, especially since this is my first warbird.

here she is, in all her shining glory (minus engine, cowl, and wings )

i think another coat is nececary, but that's only under close inspeciton, so i'm gonna wait a few days for the paint to cure.

Blimey Shupack, I turn my back for two minutes and not only have you sprayed the Corsair (I guess your wife made the most of her lie-in Sunday then?), but wait whats this MORE ?

Is it congratulations all round ????? Will we hear the sound of tiny 2-strokes ?

not yet, but she's already making plans, of course MY office space is the first to go, not hers....

Thats what happens when you let them lie-in

I've been considering going with the RCS 140 for a while now, i've found several threads saying they power the topflite birds perfectly, and I'm getting sick of glow fuel mess and price (and i've only been doing this a year) but the initial price of the engine is a bit of a drawback, untill I looked up the price of a saito 120, wow 350, same as the RCS, the Super custom is a better price at about $250 but then you have the whole "made in china" debate, i know, i have an SC 60 now, it runs great......

then someone was kind enough to supply this link in another thread

http://www.carrprecision.com/Pages/prod02.htm

that little weedeater engine looks perfect, maybe the next size up. i'll get her all together, weight the front end for the right balance, and go with the biggest engine with the right weight!

all of them swing an 18" prop, with some motorhead tinkering i'm sure i can get them up to a scale 20" :devious:

Here's how she sits right now, 6lbs, 12.6 oz


needs the underside of the wing sprayed silver, ailerons flaps and cowl primed and painted, rudder and elevator covered and painted, canopy made, and engine picked and installed, and other little things i can't think of right now.

I counterbalanced the rudder and elevator, since the pushrods are sooooo long, but do the ailerons need it on this size plane? i'm using seperate servos with about 2" pushrods

Stupack,
Can yu explain why and how you counterbalanced the rudder and elevator?

sure, i've gathered the info off of lots of threads and a few websites, so I'll just boil it down.

HOW- by inserting small bits of lead into the leading edge of the controll surface, or on an extension arm in front of the controll surface, this is easy on the tailfeathers of the corsair, because they're aerodynamicaly balanced, so the lead goes in the bit that sticks out in front of the hinge line. also lightening the back side of the surface means you need less lead, which means you need less lead in the nose. pic attached of the rudder

WHY- flutter. with long controll linkages, there's more chance of getting flutter from flex/slop in the linkag system. the best way i've heard flutter discribed is with a simple experiment. take a 1 foot ruler with holes in it (or make a stick with 2 holes) put a pencil in one of the holes near an end, to simulate the hinge line, and shake the pencil up and down (or side to side, depends on how you hold it) the ruler will twirl arround the pencil very quickly. now stick a bit of lead or whatever else on the short end to balance it, and shake again. won't spin will it?

the spinning is basically the same forces that cause flutter, but since there's a linkage the controll surface oscillates (flutters) and if it's fast and violent enough, it will rip the plane in half. quickly.
balancing the surfaces, even partially, will stop flutter, or at least reduce it engough that the linkages can cope with it.

that's the way I understand it, if I'm wrong, someone please let me know. (If i'm right a pat on the back would be nice, I just lost my daily flyer)

'nuther pic

Stupack.

Thanks for a great explanation. I appreciate all of your input and pics.

My corsair is a work in process. I have the fuse built and skinned, all the servos in and tested. The main and tail retracts in and the tail tested. The wing is partially skinned. With the retracts and servos in it weighs about 2.5 to 3 pounds at this point (if my wife's cooking scale is accurate). I'm putting a Saito 150 in it. I plan to fiberglass all except the rudder and elevator. I'll monocoat them.

Shupack:

Yea I think I've read about every thread here on which retract is better, I just wanted another opinion from someone in about the same boat (plane) as I am, cept your in the front and I'm at the rear.
Good explanation on the counter balancing. Just one thing, I'm guessing you attach the surfaces and then let gravity do the rest (kinda like a scale). Of course with the rudder you would just turn the plane on it's side. Yes?

Yes, you could attach the surfaces, I actually just installed the hinge points into the surface and held them to the edge of my work -bench, saves all the on/offf.

I weighted the front end to balance, and she needs 2 lbs exactly right on the engine mount, so a big engine is a go!

Shupack,
I trust your going to use 4-40 rods on the Rudder and Elevator. Since your going with the RCS 140 your correct about minimizing any potential for flutter. Also what servos will you be using all around? Your loads will increase for everything but the flaps. Pete