PapaVan

I am using Century Jet retracts. The mains are air actuated, but the tailwheel is mechanical and steerable. I created a slot for another retracts servo in the fuselage for retracting the tailwheel. The steering can be actuated from the rudder servo. I hope this helps you.

rcman08

Thanks. I was looking at that one but am new to building and wondered if I would be complicating things by installing a mechanical one like that and installing an air setup to operate it since this is all foreign to me.

CorsairJock

My Feedback: (90)

OK, this thread has become WAY too long to ask someone to read it all. But if you DID have the time, you would discover that some of us have chossen to install ALL of the air equipment (tank, valve, filler, servo, etc.) on the wing. By doing so, you eliminate the need to (air line) disconnects, AND you will have shorter ail-lines (meaning less air is used for each retract cycle).

IF you choose to use that method, it then becomes easier just to install an extra servo in the fuselage (doesn't need to be anything special) to actuate the tailwheel retract. Even if you don't mount everything on the wing: it's still not rocket science connecting a servo to a tailwheel retract. To me: it seems easier than messing with more air lines (and possible leaks).

The Robart and CenturyJet designs (for tailwheel) are nearly identical, EXCEPT the Robart is made of plastic, the CJ made of metal (alum?).

mystar46

rcman,

Check out my post in this thread for more Robart tailwheel info...

http://www.rcuniverse.com/forum/fb.asp?m=6513148

scratchbuilder46

Hoonnz, new to the forum so I may have missed the answer to this question. Your diagram is a side view of the Corsair nose you modified. It looks like you shortened the nose somewhat and made a new firewall correct? Did you maintain the right thrust also and how did you attatch the cowl ring? I picked up my TF kit from a club member and have ordered scale tail feathers for it. Just wanted to look through the build and get some of the ideas together I wanted to use. Yours look pretty good and I would like to use it. Thanks in advance for a response. WS

hoonnz

The nose is shortened back to scale, I can't remember the exact measurement I'll have to look it up. The right thrust is built in to the firewall. The cowl ring is mounted using the existing mount holes onto aluminium stand-offs that a friend machined up for me.
The model isn't finished yet, it has been languishing for a variety of reasons including while we built a new house. I now have a much better workshop, almost set up, so back into it very soon.
I gave up on the working cooling gills, too small to do well I think. I have got into gas engines now and I think it will be easier to do all the clever scale stuff on a bigger (84 inch?) model.

scratchbuilder46

hooNZ, Thanks so much for the reply. I have your drawing blown up to fit the plans and I see you indeed shorten the nose somewhat. I will use standoffs also, just wanted to know about the right thrust as your drawing showed the side view rather than the top view which shows the right thrust. I hope you get to work on yours again. I am still waiting for the tail feathers and doing some more mark up of the plans. Never was in NZ, but spent some time in Australia courtesy of the USN. 5 trips across the pond during the Viet Nam deal. Good luck and thanks again for the reply.

hoonnz

I'm finally getting back to the Corsair, I have temporarily removed the standoffs and cut off the balsa ring that forms the rounded-off section under the cooling gills in order to fit the scale exhausts that a good friend machined up for me.
Here are a couple of pictures that show the engine mounting box with the right thrust built into the ply shims as per the original design.

hoonnz

A few more pictures for you. You can see the cowl ring mounted on the stand-offs, the rounded edge ring fitted to the firewall and the resultant air gap which allows good cooling without any holes in the cowl.

scratchbuilder46

hooNZ, Thanks for the update. Those are some great looking exhaust stacks your friend made!!Couple of questions. Are you going to open up the cooling gills or leave the cowl ring as it is? How are you going to route the exhaust to the stacks, it looks like there is a pretty sharp bend to contend with to get things lined up. Going metal tube or silicone to span the gap? I am just getting the wing framed up waiting on retracts and Kimbrough drives for the aileron servos. I will construct the ailerons per Dave Platts method. The wood for mine weigh a ton!! Should save a little weight. Hope to get this one under 10lbs. dry weight. Please keep me in mind when you get some updates. I have read this thread over and over to get some ideas. I have no camera, so I will just go along with the rest of you readers and enjoy the build.

andernamen

My Feedback: (3)

Hoonz,

This is the same setup i had on my Corsair with a ST .90 and bisson pitts muffler. Fits perfectly in cowl. Trouble is it wouldn't run worth a darn. I could never get a low enough idle. I would scream by the field. Since you have an OS carb, maybe yours is doing better. I changed mine to a magnum .91 RFS. Haven't flown it since the change.

hoonnz

The cooling gills will be well marked to look real but not opened at all, I beleive they were open on the ground and at low speed, not all the time. The link from the muffler to the exhausts will have to be silicone as the motor is soft-mounted. The outlet pipes on the muffler will be cut short and may need to be moved to get a straighter run.
The wood for my ailerons was reject to, it was a bit heavy for one side and really heavy on the other, quite poorly matched.

Andernamen - the older ST's had carbies that were very hard to tune, you could get them right at some throttle setting but never over the whole range. I have an ancient OS carb on one and a Super custom carb on another and they have become great motors now. I beleive the newer (chinese) ST's have much better carbs, its all down to the slope of the groove that guides the barrel in and out as the throttle opens.
Also I think these motors are quite sensitive to the pressure feed to the fuel tank. I had a J-tec muffler on one and I had to blank off one outlet to get sufficient back pressure, otherwise the motor would cut in loops or verticals. The Bisson pipes are quite small, perhaps too much back pressure?

andernamen

My Feedback: (3)

I blocked one pipe, tinkered with the high and low needles, etc.....I really liked the set up and hated to make the change, but I got tired of tearing up the gear on hot landings. Tried to fly yesterday with the Magnum, but the engine wasn't set right and I didn't have the time to tinker with it. I'll have to run it at the house and see if I can get it running better.

mgowerintn

Hello All again

I am back to building my Corsair again and I have a few questions.

I am installing my Robart retracts and robostruts but when I have the retracts retracted and in the wing there is not much clearance if any at all. I am using a standard wheel that is called for in the instruction. I was wondering if there is a narrower wheel that is out there that can be used or is being used by any of you.

Also is anyone elso having spacing issues with the Retract from top to bottow on the wing where it is being secured at. I am having to slide the retract farther back from the front of the wing so it does not hit the top part of the wing balsa wood and also I installed a spacer to bring it farhter away from the top of the the wing and when i do this it sticks out above the balsa wood area on the bottow of the wing.

Last where would be the best area to place the retracts air mechanismn and servo in the wing or in the main body.

Any help would be greatful

Thanks

scratchbuilder46

I haven't got to the retracts yet on mine. I think the largest wheel you can use is 3 and 1/2 or 3 and 1/4 inch because the wing is so narrow. I do know I had to really hog out the wing ribs on the TF Mustang to get the wheels to fit flush. Play around with the mounting part of the retracts and get them as far forward and possible. Remember the struts should be at 90 degrees when the gear is down to the bottom of the wing. As far as the guts of the retracts, I have put the tank behind former 7 with a scale hatch forward of the canopy.for the air fill valve , fuel valve, and switches. I plan to put the valve and servo on the servo tray with the other 3 servos. I am putting in a scale tailwheel and will have another air operated piston aft of the tank. One thing you can't be in a big hurry with this one. Just take your time and it will come together slick as anything. I usually plan build, but the kit was too good a bargin to pass up. I have made some changes to the basic kit to better it and lighten it. Don't be afraid to experiment, that is half the fun!

CorsairJock

My Feedback: (90)

Dave Brown 3 1/2" wheels are about as narrow as wheels get in this size ranage. Altho not as good looking as the Robart scale wheels: they are easier to fit into the wheel wells AND they are lighter. I HAVE been able to squeeze a pair of Robart 3 3/4" wheels in, but it is really a tight fit, AND they weigh a lot more.

I find it easier to mount the complete air system on the wings (tank, valve, servo, etc.) Pics of my installation can be found in this thread.

And yes: it is very cramped in the retract bays. I have learned to make the inside of the upper sheeting over the retracts very smooth ( a layer of .5 oz 'glass cloth & epoxy works well) because the airlines NEED to move when the gear is cycling, and I have had problems with the airlines binding and becoming blocked becore I smoothed the sheeting over.

I also like to cant ( angle ) my gear slightly forward: there is enough retraction that the wheels will still go all the way into the well, but it puts the wheels a little farther in front of the C.G. when down (decreasing likelihood of nose-overs ).

Lastly, and possibly most important: PLEASE read this thread, which concerns a simple mod to the 615s which will make them MUCH more forgiving/ durable:
http://www.rcuniverse.com/forum/m_14...tm.htm#1880453

RCGuy41

I have been reading through this mod thread for the past few weeks; there have been quite a few good ideas that i would like to incorporate into my TF Corsair build. I have attached a PDF drawing for a possible pull pull system for hidden aileron controls. Now, the drawing is just the beginning and little crude I'm needing to measure and draw out a low profile high torque servo to fit between wing rib T4 and T5. Please review the PDF file and provide any type of feed back and or questions.

Brad

Rocketman612

My Feedback: (85)

Why would you want to complicate and weigh down the aileron controls? Can see nothing to improve function or scale appearance. I used HS-125 servos in my ailerons with good results. I know "Juice" used the RDS system in his plane way back when also with good results and it was totally hidden. here is a link to that setup but I don't know if or where to get them.

http://www.southernsoaringclub.org.za/a-RDS.html


This link shows how the system worked. It's not Juice's Corsair.


Good luck on your build,
Pete

Joe Lott

I made my own rotary aileron drivers using circuit board standoffs, some circuit board material, and an existing round servo arm. Just drill out half of the standoff to fit your driver rod and drill and tap the standoff for a set screw to hold the rod. Next, cut a piece of circuit board material to fit the servo arm and drill it to fit the servo arm with screws and nuts. Drill a center hole through the circuit board material for a screw into the standoff. Cut another piece of circuit board material drilled like the first, but oversize the center hole such that the head of the screw that goes into the standoff fits inside the hole. This piece is a spacer. Assemble parts to the servo arm (already attached to the servo) and you have a rotary aileron driver. It works very nicely. Also, I wicked a little CA in around the driver rod for insurance.

CorsairJock

My Feedback: (90)

Gotta agree: that wing is complicated enough, I don't recommend making it even more complicated.

BTW: my computer died about 10 days ago, this is my 1st post in as many days.

phil90

Well guys I have been following this thread for some time now and I finally managed to get my corsair in the air. You will have to forgive me but its the hanger 9 corsair ARTF kit and not a scratch built kit. It started out with a four stroke in but I couldnt get it to run right so I opted for the electric conversion.... so pleased I did. I got the kit from good old ebay for less than £50 delivered, bargain. Not bad for a 100 amp ESC and a 500kv motor.

I have been using a 16 x 8 prop with a 3700 rhino pack. All in all I got it converted for about £90 and yes Im very pleased. It will climb vertical all day long, well about 6mins anyway and is super fast.

maybe when I am a bit more confident with my building skills Ill have a go at a scratch build but I just wanted to show off my flying skills..not. Check out my vid but please forgive the landing. Typical of the hanger 9 retracts and the bugger broke. Well thats my excuse anyway and it caused the tumble... Thanks for all the info.

http://www.youtube.com/watch?v=69J4ZrCH3bo

Phil

RCGuy41

Hi Phil,

Nice flight, enjoyed the video, the addition of electric power to your H-9 Corsair was a nice touch, she has the power and speed of a true warbird. I have two H-9 birds (Hellcat & P-40) I took the mechanical retracts out and installed pneumatic gear from Sierra Giant scale, for the same reason you had, the mechanical gear not being able to hold up on landing on a grass field. I had to modify the wings some what so the gear would fit into the wing, all in all it was a good learning experiance for me. Hope you are able to get your bird fixed and back into the air again before the weather turns on us all. Check out these guys they are in your neck of the woods Unitracts International

Unit 5, Ebbsfleet Industrial Estate, Stonebridge Road, Northfleet, Kent, DA11 9DZ, U.K.

t.: +44 (0) 1474 359990 f.: +44 (0) 1474 359994

w.: www.unitracts.co.uk e.: [email protected]

Best regards

Brad

lgaines85

Hey guys,
Started building my Corsair and soon I'll post some pics of the building steps. By readinghtis long thread, my options of mods are high. Just waitn for the retracts to come in to install in them. Not sure on which motor to use tho. Any Ideas

Larry

andernamen

My Feedback: (3)

I have had several different motors in my corsair, A saito 1.20, Super Tigre .90, Magnum .91 and am now fitting a Saito .91. With anything other than a big 120 four stroke, you will need quite a bit of weight in the nose to balance. The Saito 1.20 is a perfect match, but you have to be very careful with all that power, I smashed mine on take off with the 120 as is pulled it vertical with just a slight bit of up elevator. The super tigre is a good match with plenty of power, the only trouble I had was getting the engine to slow down and a poor transition. Some of this may have been solvable by trying a different carb, but I got tired of overshooting the runway. The Magnum .91 4 stroke has not provided enough power. I can only get about 9000 rpm's with mine and a 14 x 6 prop. Others have reported 10,000 plus, but I cant get that. Every flight with that engine scares me. Next I'll try the saito .91 which bench tested about 1000 rpm's more than the magnum. That should make a huge difference. Hope this helps.

CorsairJock

My Feedback: (90)

As stated in previous posts: I had no trouble balancing mine with a Saito .82 up front. In fact: the rx battery pack is positioned over the wing, to acheive proper balance. If I DID need nose weight, I could just move the battery pack underneath the fuel tank.

The "perfect' engine for one is not the perfect for another. It all depends on:
1) how heavy (or light) you intend it to be. TF Corsairs can weigh as little as 8 1/2 lbs (WITH retracts) or as much as over 12 lbs. Naturally, the heavier it is: the more power you need.
2) How you want to fly it. My Saito .82 powers my 9 1/4lb Corsair just the way I like it: very SCALE like. If you are one that prefers more robust takeoffs and good vertical performance: more power is needed.
3) the climate, and elevations from which you intend to fly. Elevations of a several thousand feet above sea level require more power, due to thinner air. Likewise, consistent temps above 90 deg will need more power. (frankly tho, if it's in the 90s: I'm waiting till later in the day to fly)

Top Flite made some good recommendations for engines sizes. If you are building this Corsair, you SHOULD have ample previous experience with RC airplanes in general, and at least SOME experience with warbirds. Let your experience be the judge. If you DON'T have that experience, then you really should be building something else before this kit.