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-   -   WACO YMF (https://www.rcuniverse.com/forum/golden-age-vintage-antique-rc-196/4058627-waco-ymf.html)

khodges 03-08-2007 09:41 PM

RE: WACO YMF
 
What's going on? Every time I go to the newest page on this thread, I get a message that the message has been edited or deleted, blah, blah, blah, do I want to go back?

Have we "over-Waco'd" the system or something? :).

I started thinking about what 16 oz of gas and 12 oz of smoke fluid would do to the trim characteristic of the plane if all that weight was "out front" (next to the firewall) until it started burning off. I decided to minimize the C/G shift by moving the tanks further back, about 2-1/2 inches. This puts the rear edge of the tanks right at the c/g and shouldn't affect the balance so much. Of course, it is balanced with tanks empty, but the nose-heaviness at full tanks will be eased due to the shorter moment since the mass will be closer to the balance point. This also puts the tanks (smoke on top, fuel directly below it)in the space directly above the landing gear "hatch"

Stickbuilder 03-09-2007 06:00 AM

RE: WACO YMF
 


ORIGINAL: khodges

What's going on? Every time I go to the newest page on this thread, I get a message that the message has been edited or deleted, blah, blah, blah, do I want to go back?

Have we "over-Waco'd" the system or something? :).

I started thinking about what 16 oz of gas and 12 oz of smoke fluid would do to the trim characteristic of the plane if all that weight was "out front" (next to the firewall) until it started burning off. I decided to minimize the C/G shift by moving the tanks further back, about 2-1/2 inches. This puts the rear edge of the tanks right at the c/g and shouldn't affect the balance so much. Of course, it is balanced with tanks empty, but the nose-heaviness at full tanks will be eased due to the shorter moment since the mass will be closer to the balance point. This also puts the tanks (smoke on top, fuel directly below it)in the space directly above the landing gear "hatch"
Ken,

I'm getting the same thing happening when I try to access the latest page, so It's not something that you are doing. It may happen when the last page is getting full. I have no idea why it does that.

Landing gear Hatch??????? What's that? Be sure that you don't get her a little tail heavy when moving the tank/s. I think that the adjustable H-stab is going to be very nice when compensating for the change in C/G as the flight progresses. It should keep the model from getting droopy in the tail as the fuel burns off. It may be the biggest pain in the butt to fool with as well. Only time will tell. If I were to do it all over again, I might not even bother with it, and just make the model appear to have an adjustable H-stab. I have never liked the way that models just glue the stab to the fuse, when the full scale planes are articulated, and look as such.

Bill, AMA 4720
WACO Brotherhood #1

khodges 03-09-2007 05:27 PM

RE: WACO YMF
 
1 Attachment(s)
I agree with you on the appearance of the tail feathers. I still haven't attached mine, I wanted to get the insides all in order, and it's easier to flip the fuse around without worrying about knocking the tail off. I keep debating whether or not to make the h-stab two piece. It does look good, and if it were a kit, would be much easier as there would be less reverse-engineering to make it work and look good, but I also wonder if it's like the rib stitching we mentioned on the other thread. A stick-of-dynamite's worth of work for a ladyfinger's worth of "pop":) even if your elevator trim becomes a pain, it will allow you to at least set the tail incidence for best performance. Once you've found that "magic" spot, just leave the incidence there, lock it in place. It sure looks damn good, the whole tail assembly.

As for the landing gear "hatch", there is a removable panel that fits between the landing gear legs, it's big enough to get both tanks in and out without taking the bottom wing off. My tanks will both be mounted ahead of the C/G, but closer to it than they originally were. Because the gas engine has a diaphragm pump on the carb, tank placement isn't critical as it is on a glow engine, and the smoke system is actively pumped, so I have a lot of latitude with both tanks' placement. I placed the smoke tank above the fuel tank, this will maintain side-to-side balance regardless of the contents of either tank, and minimizes the balance shift fore-and-aft. Placing them closer to the c/g simply decreases the nose heaviness of having both tanks full.

BTW, I bought the 60-size Great Planes float kit, they measure out within a half inch of the proper length for the Waco. I'll have to bend my own wire mounts to make them fit the slotted mounts the wheeled gear goes on , but that's no big deal. i probably won't even start them until the bird is finished and tested.

Stickbuilder 03-09-2007 07:15 PM

RE: WACO YMF
 
The hatch thingie might be worthwhile doing on the kit, but as to the landing gear mounts, that would require reworking quite a bit of the forward section of the fuselage, as would going to the ARF style cabane struts. Not much bang for the buck there either. After thinking about the moveable H-stab all day, I'm glad that I did it, and was probably second guessing myself earlier. I'm probably not going to build the bottom hatch in mine, since I am going to have a spring bungee shock assembly for the main gear on mine. So I'll need the structure and the strength built into that part of the fuse. Damifino was nice enough to knock-off a couple of different compression fittings for me to make this assembly with. I'm still working on the upper rear fairing and will post pictures when it is completed. None of the top rear of the fuse will be accessable when finished, so it is imperative that all is correct prior to sealing it all up. It would require major surgery on the aft end of the fuse to go back in and change anything. Bye,

Bill, AMA 4720
WACO Brotherhood #1

khodges 03-10-2007 01:46 AM

RE: WACO YMF
 
I also plan to add the inner gear struts to mine. I've been turning some ideas over in my head on how to make a spring loaded fitting that will attach to the gear mounts and not interfere with anything. I'm 'bout tired of all the retro engineering and ready to get this thing covered. My tanks are in place for good, now, I used aluminum fuel dots on top of the fuse behind the cowl and forward of the cabane struts, and I vented the tanks out the bottom, plumbed to a piece of brass tubing, like you do. They exit the bottom of the fuse just behind the muffler. e-nuff for tonite.

Stickbuilder 03-10-2007 10:26 AM

RE: WACO YMF
 
1 Attachment(s)
Ken, here's an idea on the gear shock strut. I have posted it before, but here it is again. Just make the bolt shank longer, and add a compression spring. You can adjust the tension to the load.

Bill, AMA 4720
WACO Brotherhood #1

skylarkmk1 03-10-2007 11:11 AM

RE: WACO YMF
 
1 Attachment(s)
Ken, Bill,

Here are a couple of pix of the Barth WACO YMF over in Giant Scale Forum. Same idea, just larger

khodges 03-10-2007 11:32 AM

RE: WACO YMF
 


ORIGINAL: skylarkmk1

Ken, Bill,

Here are a couple of pix of the Barth WACO YMF over on RC Scale Builder. Same idea, just larger
Those are nice, and what I have in mind. I'll have to do the "margarine" version, as that Barth Creamery Butter is a bit rich for my blood (wallet):D. Can you say, "Parkay?"

My biggest problem with these struts is the attachment out at the axle end. The entire "leg" of the ARF gear has a fiberglass covering from the fuse to the axle, and is nicely finished and fairly hard. I can "feel" through it to a degree by pinching the sides together, but can't tell exactly what I need to do for an outboard mount for the strut without committing to cut a hole through the fiberglass where I think I can attach it. If I cut the hole, and have nothing to attach to, then I have a repair headache and still no solution. These will actually be functional, and I think they will help prevent the mains from getting bent during a botched touch-down (I know how I fly) by preventing them from spreading too far. The low-bounce Robart wheels should also help.

I guess I'll shoot craps, and if I mess them up, just tear off all the nice glass and re-do the entire gear assembly. I can feel something in the area where I want to make the attachment that might be a metal bracket, but I can't be sure until I make the hole.

Wish me Buona Fortuna

Stickbuilder 03-10-2007 01:08 PM

RE: WACO YMF
 
Ken,

Do you have the space on the gear to slip a terminal ring over the gear wire, and attach the shock strut to that? By terminal ring, I'm talking about an electrical ring connector. You could solder the connector to the gear wire, and to the shock strut.

Bill, AMA 4720
WACO Brotherhood #1

gwulle 03-10-2007 07:19 PM

RE: WACO YMF
 
Bill;
Well,I got three flights in and moving the batteries forward to a slightly nose down attitude on the CG made all the difference. I got it up and trimmed and just flew around to get some time on the engine and decided to do a roll. The roll rate is very slow compared to what I am used to and I wound up in a bottom loop. I was expecting it to roll on over and when it got inverted the bottom fell out. One of my buddies said what was that and I said it was called getting the S&*& scared out of me. I have to learn to fly this thing scale and save all the crazy stuff for the Pitts. I did manage to get some what of a decent roll using the elev in the inverted part of the roll. Everyone is really impressed with the 160 twin. I get more impressed every time I start it. I did a slow flyby and boy does this plane look scale.

Gaines

Skinny Bob 03-10-2007 07:24 PM

RE: WACO YMF
 
Would love to see a video with audio of that engine.

Stickbuilder 03-10-2007 07:26 PM

RE: WACO YMF
 
Gaines,

Great, but we need pictures of the flying. It keeps us motivated. I now have the tailfeathers built and trial fitted. The fuse rear is framed from the back of the cockpit to the tail (stringers, and the luggage compartment (switch hiding place)). I'll take some pics later this evening. Oh yes, got the Mains Silver Soldered too. It's moving right along.

Bill, AMA 4720
WACO Brotherhood #1

Stickbuilder 03-10-2007 07:52 PM

RE: WACO YMF
 
1 Attachment(s)
Okay, here are a couple of pics. The first one shows the H-stab at maximum positive incidence, and the second shows the stab in the maximum negative condition. There is no bind, and no slop. Hope it stays that way;). This one will need real tail bracing though. I don't dare allow the tubing to begin to move (I did fill it with hardwood dowell for insurance). I have not a clue if it will fly better, but It will look more scale-like.

Bill, AMA 4720
WACO Brotherhood #1

skylarkmk1 03-10-2007 08:04 PM

RE: WACO YMF
 
Bill,

When you get the camera out, get the tape also. I need the length and width of the plastic fuel tank detail for the Top wing (You already posted the pictures). Also need the distance back from the leading edge if possible. I am attempting to duplicate the tank detail in aluminum roof flashing (it might be too thick) and have been experimenting with different tools for the embosing. If that doesn't work, maybe 1/64th ply, chart tape and HVAC metal tape. Thanks

gwulle 03-10-2007 09:23 PM

RE: WACO YMF
 
Bill;
That is one neat installation ! I am eagerly waiting to see how it works. I almost tried a snap today,but thought better of it since I have not put the tail bracing. That will give me something to work on this week. I am really enjoying the build.

Gaines

Stickbuilder 03-10-2007 09:47 PM

RE: WACO YMF
 
Chordwise, the tank is 5 3/4". Spanwise, it is 14 3/8" The tank is supposed to go right at the terminus of the leading edge sheeting (on the wing panels), so it would line up on the front sub spar. Need any other info?????

Bill, AMA 4720
WACO Brotherhood #1

pimmnz 03-10-2007 09:59 PM

RE: WACO YMF
 
Gaines, I too have the same reluctance to do a `proper' axial type roll with my Waco, it needs full down elevator as it rolls inverted, but you do have plenty of time to push that stick foward...I have video of the real one rolling and it does a very slow `snap' roll with lots of dive to gain speed, lots of climb before all the rudder and elevator is is applied. English speaking people call it a flick roll, and it is accomplished at something less than full speed, in deference to the structural integrity of the type doing the evolution. In full size the flick limits (providing the aircraft is licenced to do them) are usually on a placard in the cockpit so the pilot can reference them, and there is a speed limit applicable to the type. Try this, set up for a stall turn (ie, dive and start to pull vertical) but stabilise the climb at about 45%, as the speed starts to decay put all the sticks in the bottom left corner, leaving the throttle at about 50%. The thing should cruise over the top inverted and fall out upright on a 45% downline. Looks very pretty when done at the right speed, if it tends to screw out on the way up then your entry speed is too high, and if it falls out vertically, stalled, then you were too slow, of course. Practise when no one is looking, and a couple of mistakes high, like the real thing aerobatics require the use of plenty of altitude.
Evan, WB#12.

skylarkmk1 03-10-2007 10:00 PM

RE: WACO YMF
 
Bill,

Thanks, I'll post my efforts when I get it done.

bart5495 03-10-2007 10:33 PM

RE: WACO YMF
 
Stickbuilder: Check out this video:http://www.rtptv.homestead.com/rtpbarnstormers.html.
You can see the adjustable stab.

#11

khodges 03-10-2007 11:03 PM

RE: WACO YMF
 
1 Attachment(s)


ORIGINAL: pimmnz

In full size the flick limits (providing the aircraft is licenced to do them) are usually on a placard in the cockpit so the pilot can reference them, and there is a speed limit applicable to the type.
Here's a pic of the instrument panel from a YMF Super. Note the accelerometer in the lower right corner, below the altimeters. He has his flagged at about minus 2.5, and positive 6 g's.

khodges 03-10-2007 11:21 PM

RE: WACO YMF
 
1 Attachment(s)


ORIGINAL: Stickbuilder

Ken,

Do you have the space on the gear to slip a terminal ring over the gear wire, and attach the shock strut to that? By terminal ring, I'm talking about an electrical ring connector. You could solder the connector to the gear wire, and to the shock strut.

Bill, AMA 4720
WACO Brotherhood #1
That sounds like a good idea, if I can't find a mounting point inside the fiberglass. There's definitely something hard in there, I'll make a large drill hole to see what, and if it's not an option, I'll fill the hole with epoxy putty.

I had intended to work on the tail today, but thinking about the gear struts got me to fiddling, then sketching, then cutting, and after a couple hours of work, this is what I came up with. The metal is extruded aluminum, I cut a piece from 2 inch angle stock for the bracket, and used 1/2 inch "C" channel for the strut carriers. The bolt is a 6-32, and the spring is stiff enough that I can't collapse it between my fingers. The sleeve between bracket and carrier is a nylon bushing. I mocked up the photo to show how it will mount, and put my foot long yardstick in so Bill would be happy. There will be a "C" shaped carrier down near the axle for the other end of the strut, which is made of two pieces of 3/32 square carbon fiber glued side by side. I'll fasten them with 2-56 screws to the carriers.

skylarkmk1 03-11-2007 12:34 AM

RE: WACO YMF
 
Ken,

Looks good, very good.

Stickbuilder 03-11-2007 06:23 AM

RE: WACO YMF
 
It's amazing what you can do when you are motivated. That really looks great. I'm doing somewhat the same thing for mine. I took some of the temper out of my main gear so that the gear would have more give than before. That is one lousy spot with the old Pica models. The gear is very solid and unforgiving. A hard landing can wipe out most of the fuselage.

Bill, AMA 4720
WACO Brotherhood #1

khodges 03-11-2007 11:32 AM

RE: WACO YMF
 
1 Attachment(s)
Here's a couple of pics showing the spring assembly in place on the fuse, plus the tank setup. I am just holding the smoke pump in its intended place just above the lower wing saddle I tried cutting through the landing gear down near the axle to see how it's constructed. Looks like where the wires meet is imbedded in heavy fiberglass. This is good for me; what I'll do is drill through it, and mount the lower strut carriers with a couple of 2-56 hex screws, and use lock nuts on the outside. I plan to try to make the faired shrouds that cover this area, so the locknuts will be covered. At any rate, they'll be behind the wheel, almost unnoticable anyway.

Also note the two brass tubes exiting the bottom of the fuse behind the muffler cutout. Tank vents, one for smoke, one for fuel. The tubing makes a loop on its way back to the tank, which keeps fuel from pouring out the vent tubes when the plane is at nose down attitudes.

Doesn't look like I'll get any work done today. I'm leaving in an hour to drive to Raleigh (3 hrs), taking my daughter and a couple of her friends to see Blue Man Group tonite. 6 hours in a minivan with three 14-yr. old girls, I'll probably be a bit (more) insane next time you hear from me:)

damifino 03-11-2007 12:20 PM

RE: WACO YMF
 
Making some progress. I have the crutch pinned down and will cut some formers tonight. Lookin'good guys!


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