Author Topic: New Baby Clown and SLC over Polyspan (Read 6912 times)

Larry Renger · « **on:** May 23, 2013, 06:48:36 PM »

I wanted a backup model for 1cc flying, so I assembled this ARF Baby Clown. It is powered by a Medallion .049 swinging a Master Airscrew 6x3 prop. Weight came out 6.5 ounces!

I replaced the stiff stock hinges from the kit with real Klett hinges.What a difference! Also, I substituted carbon tube for the solid wire pushrod. Plus, the stab/elevator gap is taped over.

Unfortunately, on the second flight, it caught fire.

Andy Borgogna got the fire out, but got a burn on his fingers from the melted venturi (THAT'S a new way to get hurt!). There was damage to the covering and I had to strip and paint the fuselage. It is back and ready to go again.

kenneth cook · « **Reply #1 on:** May 25, 2013, 07:35:09 PM »

Unfortunately, it's not a TD and is far from it. The Medallion does indeed work well on suction opposed to the TD. Ken

pat king · « **Reply #2 on:** May 26, 2013, 08:53:05 AM »

Larry,
Let me know if you need another Front housing/venturi. I have a few new ones.

Pat

Ron Cribbs · « **Reply #3 on:** May 27, 2013, 06:57:04 AM »

Nice Baby Clown Larry,

I have one that I built up from a kit. I use the same setup for power/fuel. The thing is the best flying plane in my fleet. Mine is now a little rough around the edges due to many newbie mishaps. I even stepped on the wing while filming a fellow flier! Still though even with all the repairs it flies like it did when first built.

Sorry to hear yours caught fire. I have heard of that happening although I have never experienced it myself.

Ron

Here is mine after a few flights in freshly mowed grass.

Andrew Borgogna · « **Reply #4 on:** May 27, 2013, 10:30:56 AM »

What Larry didn't tell you was how it caught fire. In my 60 years of flying model airplanes I have never seen or heard of this before. We just changed the glow plug and I was going to start the engine. Like I always do with Cox engines I squirted a bit of fuel across the top of the piston with the glow driver attached. That was all it took to start the fire. I have had engine fires start with back fires of the engine but never just from the prime and a hot plug. Also what I didn't realize was the fire was still burning back through the venture after I extinguished it on the plane. I thought there was some crud on the venture, what it turned out to be was melted plastic which stuck nicely to my finger when I tried to brush it off. All in all a very unpleasant experience.
Andy

Tim Wescott · « **Reply #5 on:** May 27, 2013, 10:58:09 AM »

Clearly I don't get out enough -- in all my years of flying both CL and RC I've never seen an engine fire.

Andy, I hope it's just a little irritating burn, not a deep hole with charred edges or anything.

Now if only I could get my Norvel 049 to run consistently...

pat king · « **Reply #6 on:** May 27, 2013, 01:31:46 PM »

As far as the intake area is concerned the Medallion engines have a lot smaller cross sectional area than the TD engines. The reason I have a bunch of .049 Medallion front housings is that I intend to do some testing to see how the performance of the Medallion can be improved by progressively opening up the venturi. The other thing will be to see where the suction fuel draw starts to suffer.

Pat

Tim Wescott · « **Reply #7 on:** May 27, 2013, 01:34:19 PM »

Quote from: Motorman on May 27, 2013, 12:50:16 PM

The Med is a Cox 049 front valve and all the parts exchange so how is it far from a TD? Doesn't matter, it's not a reed valve which was my point.

I'm speaking from book learning here, but:

I'm almost certain that the TD has different intake timing (big square hole in the crank instead of a smaller, cheaper, round hole), a different piston/cylinder fit (tapered on the TD, straight on everything else), and "boost" ports milled next to the regular transfer ports. All of these differences made the TD a generally more powerful engine, but not as mild mannered.

(And I'm sure that there were running production changes, just to confuse the issue).

I'd love to see some side by side pictures.

Jim Thomerson · « **Reply #8 on:** May 27, 2013, 02:21:03 PM »

I make it a practice to exhaust prime before attaching battery, and to have the prop firmly in hand when attaching the battery.

Back in the racing days, I kept a spray bottle of water at hand in case of the engine catching on fire whilst pitting. It was occasionally needed.

Larry Renger · « **Reply #9 on:** May 29, 2013, 09:35:30 AM »

Reply to several items:

The Medallion crank timing is much milder than the Tee Dee, but the hole was not particularly cheaper to do as both ports were done on automatic machines.

Taper honing and matched piston taper grinding were about the most difficult thingqs to do well. Each batch had to be calabrated and test run to get the machine settings right. And you can't just grind to what you want as a final dimension, you have to get it to where it fits right AFTER breaking in.

The slit exhaust was a fire prevention design, and really costs little in power, as the exhausts were oversize anyway (look at the Norvels, Foras, etc.)

john e. holliday · « **Reply #10 on:** May 30, 2013, 09:34:53 AM »

Will a TeeDee front end fit the Medallion?

Larry Renger · « **Reply #11 on:** May 30, 2013, 09:41:29 AM »

The parts are completely interchangeable, make a MedalDee or TeeDallion to your heart's content.

James D. Hayes · « **Reply #12 on:** June 01, 2013, 05:34:34 PM »

I've got a .15 tee dee with a medallion carb body on it, you can tell it's a tee dee when you start it, it growls more LOL. Nice running engine.

Jim Hayes

Larry Renger · « **Reply #13 on:** June 10, 2013, 09:04:49 PM »

The Clown is getting there. The handle sensitivity is still too high. There is still a warp in the inboard wing, but the flight potential is great. Good corners, reasonable speed, great engine runs.

Paul Smith · « **Reply #14 on:** June 12, 2013, 04:42:38 AM »

Back when I flew a lot of 1/2A combat I rountinely used Medalian plastic front housings on my TeeDees. I made a little bitty dump tube and ran a rear remote NVA. This did away with the expense of breaking two front housing at every contest and also allowed me to attach the bladder tube to a man-size piece of brass tubing, not the tiny TeeDee fuel nipple.

Larry Renger · « **Reply #15 on:** July 02, 2013, 07:06:23 PM »

Well it looks like another "hard luck" plane. After several sessions with the engine running flawlesly, last time it quit several times in the air, finally at a really bad place. No major damage, fortunately.

I replaced a damaged tube on the the tank and added foam underneath. More news when it happens. The plane is really ready to rip, I think the trim is ready for competition.

The most major disaster plane I ever had was my own design "Tech Terror". I built two of them and never did get it to work right. One disaster after another. Andy Borgogna ruled that the design is cursed and persuaded me to cut off the leadouts and never hang it near a model that was working. I renamed it the "Zombie Terror". ( it is currently hanging next to his P-51!

Jim Roselle · « **Reply #16 on:** July 09, 2013, 07:56:43 PM »

Nice plane! What type of tape do you use for the hinge gap?

Thank you,
Jim

Larry Renger · « **Reply #17 on:** July 09, 2013, 11:24:54 PM »

Clear scotch tape. It needs replacement now and then, as it isn't totally fuelproof.

Larry Renger · « **Reply #18 on:** July 20, 2013, 07:25:52 PM »

This plane has bad Karma!

NOW the covering has come unstuck, and even with application of Balsarite, won't stick back down.

I took off all the covering and will do a finish of my own! After I degrease the structure where oil soaked under the old covering. ARCs, not ARFs unless they are electric from here on out.

I had the same problem with my ARF Smoothie, too.

Jim Roselle · « **Reply #19 on:** July 20, 2013, 09:25:59 PM »

I understand the bad karma plane. I have built four Beechcraft Staggerwings and none have made it more than two days at the field. I am done with that plane!

Hope I'm not hijacking your thread. I just purchased a Baby Clown kit but I don't like that big canopy in the back. I want to make it resemble a Yak 50:

Will this adversely affect flight characteristics? Is that big canopy back there for a reason?

Thank you,
Jim

Ron Cribbs · « **Reply #20 on:** July 20, 2013, 09:49:42 PM »

Quote from: Jim Roselle on July 20, 2013, 09:25:59 PM

I understand the bad karma plane. I have built four Beechcraft Staggerwings and none have made it more than two days at the field. I am done with that plane!

Hope I'm not hijacking your thread. I just purchased a Baby Clown kit but I don't like that big canopy in the back. I want to make it resemble a Yak 50:

Will this adversely affect flight characteristics? Is that big canopy back there for a reason?

Thank you,
Jim

Jim,

It flies great, you will enjoy it. The large canopy is not very appealing I agree. I believe it is supposed to blend into the fuse and only the front portion is to be the actual canopy. Look up the PDQ baby clown and you will see what I mean. If you do modify it, it won't hurt anything.

Ron

Larry Renger · « **Reply #21 on:** July 20, 2013, 10:54:43 PM »

I agree, the shape of the fuselage is purely styling, and has no effect on flight.

RknRusty · « **Reply #22 on:** July 21, 2013, 01:39:27 AM »

Neither do the decals.

Larry Renger · « **Reply #23 on:** July 21, 2013, 02:05:37 PM »

OK the wing has been stripped, degreased and the frame liberally doped with Nitrate. "Here'smy plan!" : there are a number of techniques I have heard of, but never tried. And one that seems NEVER to have been attempted.

First, see if Nitrate dope really can substitute for Balsarite in adhering iron-on materials. If not, in this case, I can use thinned dope as a backup, since the covering will be Polyspan.

Second, I plan to put SLC over the Polyspan and bond it down everywhere as best I can. Hopefully, this will yield a super tough covering at minimal weight gain.

Finally, the plan is to see how good,and durable a finish can be applied over the SLC. No filler or primer should be needed.

Worst case, is it needs be done over, but at least it isn't my next Nats stunter.

Larry Renger · « **Reply #24 on:** July 21, 2013, 07:09:19 PM »

OK phase 1 is done. The wing is covered with Polyspan. That's the good news.

The bad news is that if Nitrate dope works as a heat activated adhesive,it must be at a really high temperature. I was already at the shrink temp for the covering and got minimal adhesion.

Fortunately, my trusty dope bottle and brush were ready to hand and the day was saved!

One good thing is that having a hot iron available makes perfect wingtips easy! Heat stretch, pull and dope the edges.

Tomorrow, when the dope is thoroughly set up, I'll try the SLC top coat.

Larry Renger · « **Reply #25 on:** July 22, 2013, 04:13:00 PM »

Well, I took the chance and covered SLC right over raw Polyspan on the Baby Clown.

It works fantastic! It looks like very glossy Polyspan. No dope yellowing and no dope drip run throughs. You can see where you have and haven't bonded the SLC to the Polyspan and fix those areas. The bonding is visibly 100%.

The added structural rigidity is amazing.

I have some technique to work on as far as flawless tips, but the ones I did aren't horrible.

And it took about as much time as a couple of coats of dope! The weight, by an actual test sample, is 1.46 oz/sq.yard.

Now I need to work on how to properly paint it. I have a sample piece drying. It is Painters' Choice right on the steel wool buffed SLC. I suspect that wet sanding with 600 grit would work better, and will try that too.

For my next project I will iron on one of the super light colored films, and no paint needed!

Larry Renger · « **Reply #26 on:** July 22, 2013, 06:29:00 PM »

Here is a photo of the covering.

john e. holliday · « **Reply #27 on:** July 22, 2013, 07:59:32 PM »

I will have to try that now.

Larry Renger · « **Reply #28 on:** July 22, 2013, 08:44:45 PM »

Quoting Yoda: "There is no "Try", there is only do or not do!"

Larry Renger · « **Reply #29 on:** July 22, 2013, 09:35:39 PM »

Super light covering. I believe it is available from Corehouse.

It is a very thin Mylar with a very thin adhesive coating. Do a search in the finishing forum and you will find many words devoted to its use.

As noted above, it is usually applied first, then the silk, Polyspan, etc. applied over it. Didn't make sense to me, so "I did it MY way".

Mike Griffin · « **Reply #30 on:** July 22, 2013, 10:02:03 PM »

This is what SLC looks like by itself as a covering. By the way Larry, this is how I did my little 51 Electric mustang... I know you were working on yours...did you finish it yet?

Mike

Larry Renger · « **Reply #31 on:** July 22, 2013, 10:08:58 PM »

Nope, but it is actually coming along. The fuselage is covered with carbon veil, the flying surfaces are all built and ready. Final assembly is imminent! I will be doing mine in the decor of Bob Hoover's first "Old Yeller". The artwork is ready to print on decal material. The covering for the wings and tail will be Coverlight. Fuselage and vertical tail to be done with Painters' Choice.

Mike Griffin · « **Reply #32 on:** July 23, 2013, 08:06:35 AM »

Sounds good... post some photos when you finish...we are making Eric proud....

Mike

Larry Renger · « **Reply #33 on:** July 26, 2013, 08:45:19 AM »

The finished Baby clown, ready to fuel up and fly weighs 7.04 ounces. Hopefully,it will take to the air tomorrow.

Larry Renger · « **Reply #34 on:** July 28, 2013, 09:52:18 PM »

It is going well so far. I think there may be too much tipweight, but I may be overcontrolling and stalling the wing. When I do a quick climb and pull out, the wing whips badly. This has deleterious effects on line tension on maneuvers like the square eights and hourglass! Places you want to be rock solid.

I have reduced the throw of the elevator yet again, and will give it another shot tomorrow. The tipweight is buried in the wing, and I will just have to add some external weight to the inboard tip if that is actually the problem. Something to think about on my next 3 kits. Adjustable leadout position would be nice too. How come they don't engineer this as a full Nats ready stunter?

john e. holliday · « **Reply #35 on:** July 29, 2013, 09:19:03 AM »

I think that it is a sport plane for the guys/gals that fly for fun. Not for the full all out competition flyers like some of us.

Larry Renger · « **Reply #36 on:** July 29, 2013, 05:04:23 PM »

You are right, of course, but I just have to push things to their limit and see how good I can make it. Not out of ideas yet, and I have had 3 others before this. They all reached the point of being competition fliers.

Model #1 was powered by a PAW .035, and weighed 5 ounces. It was built from a kit. It died when it hit a traffic cone while flying at an airshow.

#2 had a Tee Dee running pressure, and I flew it at VSC in Old Time. I gave that one to a young flyer. Kept the engine of course.

#3 is alive and well, living on one of my airplane racks. It has a PAW 1cc for power. It was twhe model I used to win the Leprechuan trophy two years in a row.

Mike Griffin · « **Reply #37 on:** July 29, 2013, 09:38:51 PM »

Larry what is a PAW?

Thanks Mike

Larry Renger · « **Reply #38 on:** July 30, 2013, 08:42:47 AM »

Progress Aero Works,a company in great Britain that makes model diesel engines. They are imported by "Dr. Diesel", Eric Clutton. Sizes range from .55 cc (.035 ci) to at least .40 ci.

My smallest diesel is a.006 ci Valentine. My largest is an OS .25 FP with a Davis head conversion.

minnesotamodeler · « **Reply #39 on:** July 30, 2013, 04:54:55 PM »

Quote from: Larry Renger on July 22, 2013, 06:29:00 PM

Here is a photo of the covering.

That oughtta be tough as a boot.

As we said when first using iron-on covering, it makes a really nice plastic bag to carry the broken parts home in.

Larry Renger · « **Reply #40 on:** August 04, 2013, 08:41:57 PM »

I still haven't gotten the engine run squared away, and the next contest is next week. The plane seems to be ready for competition if I could get consistent power. That electric version kit on my shelf may be going up in priority. WAY UP!

Larry Renger · « **Reply #41 on:** August 13, 2013, 11:01:30 PM »

T'ain't perfect, but took first place.

The engine is working great now. I am using a Merlin plug with 3 gaskets, 15% Nitro and 22% oil. The tank is a #8 Perfect, and is way too large. Would you believe 40 extra laps?

Btw with the SLC instead of dope, this Baby Clown is a full ounce lighter than the one with doped Polyspan!

RknRusty · « **Reply #42 on:** August 14, 2013, 09:35:13 AM »

I guess 1'st place will do.

Congratulations on a successful build.
Rusty

Jim Roselle · « **Reply #43 on:** August 14, 2013, 05:49:03 PM »

Congratulations! It was a long road for that particular airplane. What are the control throws on your clown?

Thank you,
Jim

Larry Renger · « **Reply #44 on:** August 14, 2013, 06:51:28 PM »

The handle spacing is about 1.25" on my hard point expo handle. The control horn is 9/16" from the elevator centerline. Balance point is 1-1/4 back from the leading edge. Lines are 46', but probably should be 2' shorter.

Author Topic: New Baby Clown and SLC over Polyspan (Read 6912 times)

Jim Roselle

Jim Roselle

Mike Griffin

Mike Griffin

Mike Griffin

Jim Roselle