Back plate with only one fill tube?

OldTimerMilt Sat Dec 25, 2021 1:17 pm

I just came across two Cox .049's that have only one fill port on the backplate. I can't figure out how to put fuel in the tank. I have been modeling for 69 years and have never seen a Cox with only one fill tube. Anyone know how to fuel this system? They came on two 1/2 A Old time planes, a Lanzo Bomber and a Playboy and are propped with 8x5 wood props for slow endurance flights. I have seen some Cox engines with the dual slit exhaust ports, but not sure why they are that way, although I had one with an exhaust sleeve for throttle - really worked well. I forced some fuel into one engine and it ran just fine, but still got a lot of fuel on the floor when trying to fill it. Any suggestions or knowledge on this engine will e appreciated, as they are in excellent shape. Thanks, Milt

Back plate with only one fill tube? Img_0011

Back plate with only one fill tube? Img_0010

**944_Jim** Sat Dec 25, 2021 1:39 pm

Ah, a Christmas newbie! Welcome to the CEF...please stick around. What you have there is a Cox Texaco engine. These were built for slow-turning endurance free flight. Yours has the later plastic back plate. I don't have any experience with the plastic ones...for any Cox engine.

The metal backplate, single-fill backplates had a vent hole right next to the fill pipe. If one used a thick fuel line to fill the tank, the line would actually cover the vent this causing fuel to spurt all over the place. I suspect your plate one may be the same. But if not, then filling the tank while holding the model upsidedown would allow for venting the tank via the "now at top" fuel pickup.

I had a Mosquito with twin .074 engines. The tanks were plumbed such that it required filling the tanks while the nose was pointed straight down. The tanks vented out during fueling iperations through the fuel pickup tubes.

Please get a close-up shot on the backplate showing the fuel pickup. It may be the tiniest hole you'd think to find. Otherwise, I vert and fuel.

OldTimerMilt Sat Dec 25, 2021 1:54 pm

OK, I just figured out while surfing that the slits for the exhaust indicate that this engine is a TEXICO Cox .049. I still don't know how to fuel it with the single tank fill nipple. I did find some backplates just like this on eBay though. Still stumped.

sosam117 Sat Dec 25, 2021 2:36 pm

Welcome OldTimerMilt!
What you have there is the Cox .049 Texaco engine with the 8cc tank.
And it has the rare Texaco glow head (with the extra fins) compared to a std. Cox glow plug.
If you look at my avatar I have just a few of those engines.

If those engines were on a Lanzo Bomber and a Playboy Sr. they were built for SAM's 1/2A Texaco event.
SAM is for Society of Antique Modelers, which I'm a member of.
The 8cc tank was for the old rules years ago, then the rules were changed to the 5cc tank (Cox Texaco Jr.)
Same engine, just a smaller tank.
Those engines were designed for a long run because the SAM 1/2A Texaco event is for the engine run and glide to total a flight time of 15 minutes.

Here are the rules for that event from SAM's rule book:

1/2 A Texaco entries shall be Old Timer designs having a minimum 8 ounces per square foot of plan-form wing area;
and powered by a .049 cubic inch Cox reed valve engine with a 5.1 cc integral fuel tank and a propeller limited to 8 inches maximum diameter.
The engine shall be a stock Cox Texaco Jr. or Babe Bee. Other Cox reed valve engines, such as the Black Widow and the Golden Bee, are acceptable with a 5.1 cc capacity tank installed using a conversion kit such as the Cox #1596.

The following modifications are allowed: moving the fuel pickup to the bottom of the tank, adding a muffler, adding a needle valve extension, and adding head gaskets. An RC engine cut-off is not required.
The fuel tank may be filled by the contestant and topped off with the engine running.
The models may be hand launched or ROG.
The score is the sum of the best two of three 15-minute max flights.

I have won that event three different times over the years (from 2007 to 2014)
It's a popular event in SAM because it is inexpensive.
You just need a 2-channel radio an old-time airplane (designed before 1950) and the best size plane for the event is a plane that is either a wingspan of around 36 to 44 inches or a wing area of around 250 to 320 sq. inches and weight no less that 16 oz. (1 pound) ready to fly.

The reason for on fill tube is all that you need to fill the tank. If you look carefully, you will see a very small hole on the other side of the needle valve. That little hole is there to let the air out and when the tank is full, the fuel will squirt out of it as well.

Looks like the previous owner may have been (or is?) a member of SAM?
Go here for a SAM Chapter by you:
http://www.antiquemodeler.org/

My plane I used to fly 1/2A Texaco with is the Playboy Sr. which you have.
It is a nice gentle plane. The wing sitting on top of a pylon and is a very stable plane to fly because of the wing being higher.
Same thing with the Lanzo Bomber.

My setup for my 1/2A Texaco plane with the Cox engine you have is:
I have used the same 8x5 Zinger wooden prop (on calm to 5 mph winds) with higher winds I use a Cox 7x4 prop.
With the 8cc tank I was getting about around 6 to 7 minutes on the engine run with no nitro in the fuel and castor oil content was 22%. You may want to use 5% nitro in your fuel because I don't know how that engine is set up to run?

This might be too technical but:
I have carefully worked my engines over for the correct timing (cylinder shims), sub-port induction to get the best performance (longest run) I can out of the Texaco engine.

As for the Texaco glow head, I don't use it when I use no nitro because the engine cools down too much and quits. If you use 5% nitro, using a std Cox glow head would be no problem. Just remove the Texaco glow head and save it for when you want to sell the engine (again) as a true "Cox Texaco Engine" as those glow heads are hard to find/get anymore.

Sorry I don't have a photo to post of my 1/2A Texaco Playboy Sr. but here is the collection of my Cox Texaco engines that I have used for the SAM's 1/2A Texaco event.

Have fun with the engines and the two 1/2A planes that you acquired (Lanzo Bomber and Playboy Sr.)!

Back plate with only one fill tube? A_texa11

SAM Life Member 3556

sosam117 Sat Dec 25, 2021 3:01 pm

Here is an article for you to read on the old SAM rules.
Jim Reynolds made up an engine for the Texaco event, before the Cox made the Texaco engine.
But it will give you the idea on what you have?
file:///C:/Users/Owner/Downloads/Playboy_Sr_oz3075_article%20(1).pdf

OldTimerMilt Sat Dec 25, 2021 4:02 pm

Jim and Sam: thank you so much for the info. I took a picture down at the shop a few minutes ago when I went down to feed my stray cats. There is indeed a pinhole next to the filler tube. I do have some small 1/2A fuel tubing that I will use to fill the tank and avoid fuel spills. I have flown the 30 second climb and glide with my 72" Playboy Sr with a K&B .21. I have also a 96" Lanzo Bomber that I flew one mex time with fuel so many oz per pound. One day I was up with it pretty high and the guy next to me said "There are two of you up there!" We looked closer, and an 8 foot span eagle was floating right behind me checking me out. After a few minutes he turned away and left. I was in glide mode by that time so there was no engine noise. I got the Bomber and the 72" Playboy from Bob Munn in California, who is now deceased. I know there are a lot of us "old timers" around. I got these two newer 1/2 A's from Bill Cowley. Bill Cowley was recently put into an assisted living home, and his sons are clearing out his "air force" for him. I bought his Sr Playboy and a Lanzo Bomber (.21 size), and the son gave me the 1/2A planes because he knew there aren't any other flyers in our club who do old timers. I run a climb and glide fun fly for the club every year, and I am the only one with an old timer that flies. We have cut our climb time to 20 seconds because the successful plane will climb out of sight in 30 seconds. I have set up 3 classes - competition sailplanes, any other electric, and any nitro/Old timer. Three years ago we had a weather front comin in from the south over Utah Lake, and one guy was up, power off and still climbing. I took up my Playboy Sr to get into that lift. I stayed up for 26 minutes, got tired, and spiraled down to land because my competition was still above me and had about a 5 minute lead. He decided to come down after I gave up, and he was up a total of 34 minutes. He was flying a Radian foamie sailplane. This past September, I took off my Playboy Sr and headed skyward. About the 18 second mark I either hit a gust or had a radio glitch that made an abrupt move, and the wing came off. the fuse spiraled straight down into the river while the wing fluttered off. a friend recovered the fuselage which was pretty much undamaged except for the pylon torn off and lost. He also found my wing a ways on the other side of the river. Its nice to have friends like that. Anyway, thanks for the info which will get these planes flying again.
Milt

Back plate with only one fill tube? Backpl10

706jim Sat Dec 25, 2021 5:05 pm

Just fill the tank with a hypodermic needle fitted with a large needle. You can file the point off to prevent accidently sticking yourself. I used one all the time on a Pee Wee to limit engine run time for free flight.

sosam117 Sat Dec 25, 2021 5:11 pm

Milt,
SAM has a fun-fly (get together) at Eloy AZ the 3-day weekend of Martin Luther King weekend.
If you want to make it there?

**944_Jim** Sat Dec 25, 2021 6:44 pm

Warning, the following is not a recommendation to do stupid stuff:

As far as filling goes, I have used a buddy's used/washed syringes to fill a tank. Leave the needle on the syringe so it goes down inside the nipple. The needle should be a small enough gauge to allow air to escape past the filler. However, the process of filling his puny syringe was so slow I went back to filling via the vents while pointing the nose down.

Puic Service Announcement: Do I have to recommend not injecting oneself with nitro fuel or any other silly fluid?

roddie Sat Dec 25, 2021 8:07 pm

Hi Old Timer Milt. Welcome the Cox Engine Forum.. and Merry Christmas!

I have a later Cox Babe Bee .049 that has a single-nipple on its "metal" backplate. As 944_Jim mentioned; there is a small vent-hole just beside that single-nipple.

See my engine below;

Back plate with only one fill tube? Dsc04313

Back plate with only one fill tube? Dsc04314

Not much space in-between the fill and vent.. What?

but there is a vent.. and yours should be no exception.

I would use Dubro #221 sm. size blue-silicone fuel-tubing on the fill nipple. Just cut a 1/2" length piece and stretch it 1/2 way over a 1/2" length of rigid (Brass) tube and connect that (adapter-sleeve) to the tubing on your fuel-bulb. As you know; it doesn't take much more than a "squirt" to fill an 8cc tank-bowl. Your Cox Texaco engine uses an 8cc bowl.

The "twin-slit" exhaust-port configuration came later.. after reports to Cox of "burns" experienced when attempting to prime through the exhaust ports of the reed-valve engines. Subsequent to the slit-port design; Cox experimented with various "wraps" around the outside of the cylinders.. consisting of a "steel-band" not unlike an automotive-style hose-clamp's band. Another type was a screen-mesh material.. likely made of Stainless Steel. These were early though.. I'm fairly certain that the "slit-port" design superseded both.

Being an endurance designed engine, I'm not sure of the % nitro that you'd want to run.. to take full-advantage of that aspect.. but Cox had a 10% formula that was (I believe) the lowest nitro that they offered.

Back plate with only one fill tube? Glow-p11

Note; the % of castor in that blend.. compared to the Dow-Lube/Klotz KL201 synthetic.

The 8 X 5 propellers seem a bit "steep" (pitch-wise) but I'm not real knowledgeable on the Cox Texaco engine. The 5-fin glowhead is stock.. and provides additional cooling; I assume because of the "lugging-effect" imposed by the larger diameter propellers.

Any way you slice it; Have Fun, Be Well and Prosper in this New Year! Hand Shake