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  • December 07, 2021, 11:55:04 AM

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Author Topic: Baby Clown Completion  (Read 596 times)

Offline Dave Hull

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Baby Clown Completion
« on: November 18, 2021, 09:26:47 PM »
Felt like I ought to send out a thanks and a status report on the latest Baby Clown in our neck of the woods.

Since we had a 1/2A Fun Fly pending, I looked over my very well flying--but now vintage--Baby Clown and realized that it had some severe hanger rash. A broken LE, split covering, and some paint damage on the nose from the high(er) nitro fuel. It had already suffered in a prior crash. The truck carrying it was demolished, but the plane was merely seriously damaged. Subsequently repaired (but not very cleanly) it flew on again for years....

Two weeks ago, a friend made an offer I could not refuse. A nearly completed Baby Clown that needed to find a new home. The woodwork on this one was done by Jim Leuken. Then he had a friend paint it. I believe he said it was car paint. Must have been some back-masking and color sanding involved because the surface is pretty smooth over the trim areas.

Since my vintage BC was needing some significant repairs, I got on the stick to finish up the new one. I installed the controls, hinged the elevator, and terminated the pushrod. Made up some landing gear, solder washers and collars. Formed and soldered the solid leadouts.  Also had to put together an engine. My original BC was built around a Medallion, and this one came with the squared off end that would accommodate a Brodak radial mount for a Cox. So no quick engine swap. And it needed a large tank with stunt venting. Hmmm. I took three old Black Widow carcasses (sold to me as "runners") and proceeded to go thru them. Finally, I just combined the best parts from the set.

It needed a pretty good chunk of lead up front (lead firewall plate, not yet installed in the picture) to get the balance close, and the ready to fly weight was 8.1 oz. That should be in the range of good performance if the engine is making good power.

Come the day for the first flight, it doesn't hold a needle very well and routinely quit on lap two or three. But it flew. Sounded like fuel feed issues, with maybe the reed hanging up on the retainer. Back home, I tore the engine down and everything looked fine, except the plastic reed was slightly cupped. So I swapped out the plastic racetrack reed for a stainless version and reassembled. It is ready for another test, perhaps this weekend.

Thanks, Jim for the airplane!

Offline Mark Mc

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Re: Baby Clown Completion
« Reply #1 on: November 20, 2021, 01:30:19 AM »
Dave,

Nice looking airplane.  When you say it doesn't hold a needle well, is it because the needle is backing off?  Looking at the picture, it looks like you're just depending on the spring to hold the needle setting.  I'd definitely go with the fuel tube and #4 washer on the needle method to maintain the needle setting.  And I'd probably stick with a mylar reed.  The steel reed is more rugged, but you  get less RPMs from a steel reed over a mylar reed.  Doesn't seem worth it to me to use a Black Widow, and then hamper the RPMs.

Mark

Offline Dave Hull

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Re: Baby Clown Completion
« Reply #2 on: November 20, 2021, 08:17:21 PM »
McMark,

Thanks. The guys that did the work on this one did a nice job. Picture doesn't do justice to the paint work. The paint seemed impervious to 25% nitro, which is really nice.

As far as the engine issue, I don't think it was due to a "wandering needle."  This one probably just had the plastic reed cupped and interfering with the retainer. It was definitely cupped when it came out. With ancient Cox parts, sometimes you get odd results.... 

When I get a chance, I'll run it again with the new reed. That would have been tomorrow, but they are predicting very strong winds all day. A good day to stay home and fix or finish other stuff.

The down side to the fuel tubing on the needle to seal things up and hold position is that there is hysteresis in your adjustment. If you want to set right at peak (like in Mouse racing) you don't want to keep nudging the needle and have it creep back where it was due to windup of the tubing. Yes, it works. If you don't need it to seal up your needle, then you have one less annoyance.

I'm not too worried about maximum engine performance on this plane. I suspect that what's there will haul an 8 oz. plane with no issues. If it doesn't, then we can unleash a boatload of Mouserace improvements on it....

Dave

Offline Larry Renger

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Re: Baby Clown Completion
« Reply #3 on: November 21, 2021, 07:38:32 AM »
A brand new mylar reed runs fastest, but they don’t last long before distorting, especially if you run the engine hot. The Venom used a stainless steel reed and performance is the best of any Cox reedie!
Think S.M.A.L.L. y'all and, it's all good, CL, FF and RC!

DesignMan
 BTW, Dracula Sucks!  A closed mouth gathers no feet!

Offline Bootlegger

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Re: Baby Clown Completion
« Reply #4 on: November 22, 2021, 08:29:34 AM »

  Guy's where would be a place to find a full sized of 1/2 A or Baby clown, also what weight would a good weight to shoot for including the engine and finish, as well as line length..  I plan to use a Medallion or a T D for power Mucho Grasses  ...
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Offline Dave Hull

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Re: Baby Clown Completion
« Reply #5 on: November 23, 2021, 01:57:36 AM »
Legs in Boots,

Sounds like you are looking for plans? You can get these direct from Brodak, I'm sure. The plans were drawn by a friend of mine, Dave Braun. I think along the way, they may have changed the fuse to a conventional mount with two bearers. I know that they have done that with others in their 1/2A line. But if you want to run a reedy, it should be no trouble to cut it down and use a plastic engine mount....  This is how my latest BC is built.

The Medallion is an excellent engine for this plane. I ran my old one for a number of years and it always flew better than I did until the wind got above 10 mph or so. Then you tend to get pushed out of the tops of loops, etc. I have always flown mine on .008"x42' stranded steel lines using an RSM (Renger) adjustable 1/2A handle using the 1-1/2" spacer. These are great for fingertip control.

I wouldn't hesitate to use some light gauge Spiderwire for this plane. Not sure if it would be best at the same 42' or not. It would depend on the drag. I have never run side by side comparisons, so I can't comment further on performance.

I liked a Cox black 5x3 prop and a pretty rich setting on the Medallion. It ran a 4-2-4 just fine, but lacked a bit of umph up top. More recently was using an APC 6x2 and running closer to peak. Really good drive with that setup. Depends on what you want to do. I think the TeeDee would want to run in the 6x2 mode, but the issue will be to get good fuel draw. There's ways to get there.  You might want to review the old Model Aviation article by Barry Baxter on his 1/2A Stuka. If memory serves, he flew that with a TeeDee on a hard tank and included some tips. (Far?) less useful would be the setup details for TeeDee Ridiculous design by Rich Porter. I seem to recall he was running bladder pressure?  Too many years since I've seen those articles....

My original BC with Medallion, custom tank, .035" aluminum gear, tailwheel and Rustoleum paint weighed 7.3 oz, ready to fuel. It no doubt gained a bit after patching it up from the truck crash. It flies fine at that weight. Tip weight is 1/4 oz, just like the plan recommended.

The Divot


Offline afml

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Re: Baby Clown Completion
« Reply #6 on: November 23, 2021, 05:10:40 AM »
Hi Dave,
Thanks for your response to the thread and the picture of your Baby Clown.
Is that a Tee Dee head on your motor?
HAPPY THANKSGIVING, STAY SAFE, & "Tight Lines!" H^^
Wes
Wes Eakin

Offline Dave Hull

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Re: Baby Clown Completion
« Reply #7 on: November 23, 2021, 10:47:34 PM »
Wes,

That's just a regular Cox head, not a high compression type. In the conversation below, you will see why I did that.

I misstated the APC prop size in the earlier post. I actually ran it with the 5.5x2;  it was not a 6" diameter.

Might need to clarify the "umph up top" comment, too.  With the original 4-2-4 setup it was a lot of fun, but when it came on, it came on hard. Made it more difficult to do anything very accurately. That's ok for blasting holes in the sky (I mostly do that), but when all the guys at the field want to see a real figure eight and not some donked up lazy eights, then you gotta change things up a bit. So I ran extra head gaskets and knocked down the nitro. That helped, but still--a sport plane. Less mild-to-wild, but also less power on top where you would like a bit more. The current setup is a completely different animal. It is very close to the Heman Lee setup of 10 or 15 years ago. We compared notes which was a great help, allowing me to converge on what works quickly. Thanks, Heman!

I have posted more of the build modifications and setup on the older BC before. Not sure where that thread went. I could add the major ones here if it helps anyone....

This picture is on it's first day out (or so) and I had not painted the canopy or put on any other trim yet.

Dave
« Last Edit: November 24, 2021, 12:37:27 AM by Dave Hull »

Offline Bootlegger

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Re: Baby Clown Completion
« Reply #8 on: November 24, 2021, 07:34:10 AM »

  What size B/C goes in the 1/2A version of the baby clown??   Obliged... H^^   y1   y1 
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Offline afml

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Re: Baby Clown Completion
« Reply #9 on: November 24, 2021, 08:50:20 AM »
Many thanks again Dave! y1
Every bit of info helps a lot!
STAY SAFE & "Tight Lines!" H^^
Wes
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Offline Dave Hull

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Re: Baby Clown Completion
« Reply #10 on: November 24, 2021, 07:35:46 PM »
From past notes:

1. The plane is built from a Brodak CLP-11 kit with stock aerodynamics, but is constructed more like a larger profile stunter. I cut out a new fuselage plank so I wouldn’t have a splice joint from converting it from a tank mount to a beam mount.  I used ¼” spruce motor mounts and 1/16” plywood doublers. I planked the wing center section out one rib bay using 1/16 balsa with the grain running tip to tip. I replaced the leading and trailing edge pieces because I thought the kit wood was too fragile.

2. The wing and horizontal tail are covered with transparent blue Monokote—because that was what I had in the scrap box. While it does work, it is heavier than it needs to be and probably harder to cover small parts than a lighter covering material. All of the fillets are SIG Epoxolite. A few coats of Rustoleum auto primer and then some Rustoleum blue enamel for the topcoat. The complete plane, less fuel, weighs 207 gm (about 7.3 oz.). The CG is 1-3/8” behind the leading edge--well behind the recommended location--which makes the plane pretty quick.

3. The engine is a stock Cox Medallion on suction. The head is a regular Cox head. I have been using between .006” and .010” of head gaskets. I put silicone tubing over the needle valve to keep it from turning in flight and hopefully to eliminate air leaks. The needle is somewhat vulnerable to damage during hand starting.

4. I fabricated a custom wedge tank that holds 0.93 oz. The dimensions are approximately 7/8” high by 1-1/2” wide by 1-1/2” long. The wedge is a true 90 degrees. The tank has standard vents and is made from K&S .010 solder tin, 60/40 solder, and copper tubing. To keep the tube joints from fatiguing I placed a Foremost brass washer over each tube to help form a solder fillet. I installed fuel tubing with 45 degree bevels on both vent tubes. There is room for a bigger tank. Others have recommended 1-1/4 oz. to allow a full pattern with a Medallion engine. A larger tank will also desensitize the current CG location a bit.

5. I have run various fuel mixes and the plane doesn’t appear to be particularly sensitive. I started with a quart can of Powermaster 35% which I dosed with another 10% by volume caster. This gives a mix of approximately 30%N, 26% oil. I have varied the fuel to match the conditions and the number of head gaskets. I was previously running this setup 4/2 believe it or not, but the pilot wasn't coping well with the large power surge at the start of each maneuver. To detune it, I added head gaskets.

6. For the 4-2-4 setup, the best prop so far is a Cox 5x3 black nylon. Expensive little rubbery things that like to slice your fingers so I sand down the edges before using. There is plenty of performance, so you can afford the added safety. If you want to run a straight 2-cycle, go with an APC 5.5x2 This is slightly better than a black nylon Cox 6x3 or a Windsor MA 6x3 prop.

7. The leadouts are .018 stranded cable with fixed exits located per the plans.  The bellcrank is a stock Brodak C-40 (about 2-3/32” leadout spacing) with the pushrod in the hole shown on the plans. The horn is a standard 1/2A plastic part (not the one molded on the same runners with the bellcrank) with the pushrod in the outer hole. This is about a 0.66” radius.

8. The only lines I have used so far are 42'x.008” stranded cable. I prefer the very lightweight RSM 1/2A handle using the 1-1/2” spacer. The lighter handle is important since the line tension is so small that a heavy handle means you will lose a lot of feel. Remember, controls are about ratios. If you use a 1/2A handle with spacing around 1-1/2", that matches up well with a 1/2A sized bellcrank. If you insist on using the same cable-style handle you use on your .35-sized stuff, I can't help you.

9. The engine is mounted on 2 degree nylon wedges from Brodak. The rudder offset is 3/16”.

10. The landing gear is homemade and uses .035 aluminum main gear legs with modified 2-56 screws for axles, mounting Williams Bros 7/8” wheels. These make it look like a “scaled down real stunter.”  The aluminum stock I scrounged does not have quite enough temper, so I have to straighten things out frequently. I find there is more damage from holding the plane during starting than from landings. I have to remind myself to be gentle. The tail gear is a tiny ½” rubber-tired wheel mounted on a two-piece soldered .032” music wire leg. With this setup, the plane lands great. With the more forward mounted gear shown on the plans for the radial mount, it’s gonna hop….

Online 944_Jim

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Re: Baby Clown Completion
« Reply #11 on: November 25, 2021, 07:07:22 AM »
Thanks Mr. Hull! Your notes are copied and stapled to my build wall along with a picture of the plane.

Offline Bootlegger

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Re: Baby Clown Completion
« Reply #12 on: December 04, 2021, 08:40:41 AM »

  Gotta nudder question? what is the wing span of the 1/2 A Clown ?  Again much obliged... H^^ H^^ #^ :!
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Offline Dave Hull

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Re: Baby Clown Completion
« Reply #13 on: December 05, 2021, 12:15:04 AM »
Boots,

That's a pretty simple question--but has a bit longer than expected answer:

The plans say 25-1/4" wingspan.  So does the kit box label....

The plans scale out to about 25-1/16" according to my tape measure....  (Musta shrunked up some?)

The Jim Leuken-built job that started this post measures out at 25-13/16", which adds about three square inches. Not sure if he used the stock LE and TE pieces or not. The tips aren't magically "growed," either....

I'd tell you what the span on Baby Clown No. 1 is, but it's too cold to go get it tonight. I might have stretched that dude, because I had to put new LE and TE stock into it. The boxwood was well past stunty and down into punky....

The Divot

PS--An unusual Baby Clown factoid:  the stock BC does not have a wing spar. But the ARF does....

PPS--I throwed in another shot I had of the Leuken BC. Here, it is being checked for incidence of the front of the fuselage before the engine mount is installed and drilled. The wing has been leveled and the tail checked. Since the airframe is so light, a single rubber-jawed clamp is able to hold it firmly in place during measurements. Butting the nose up against the machinist's knee simulates the engine thrust line if the plastic mount is fully seated, which was my goal. At this point, I have already installed the elevator using spectra line for sewn hinges. Light, easy, and super strong.


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