throttle backplate

Sweet! Can I turn the throttle control horn 180 degrees?

duke.johnson wrote:Sweet! Can I turn the throttle control horn 180 degrees?

Yes, I don't see why you couldn't. The choke tube is only an air intake and the throttle is only restricting it. The needle valve/spraybar can be mounted in any position. The backplate will fit on any .049 bee style case.

Yes, onto any Cox .049 crankcase, even the Die Cast ones if you first change the reed retainer and crankcase gasket. However, the throttle will not work properly on engines with SPI (Sub Port Induction) setup, which pretty well rules out the Black Widow and the Golden Bee in their OEM configuration. A workaround is to change the cylinder to a non-SPI one such as this one (you can use your existing piston):

http://coxengines.ca/cox-.049-cylinder.html

The needle can be in any position but the throttle has to move with it as the choke tube only fits on the backplate one way.

Yes, you can move the servo arm to the other side.

Bernie
I just ordered the backplate last night. I was hoping to have a fast engine on a throttle for a C/L carrier plane. What would you suggest? Later, after proof of consept. I will want to build another with a TD. I have an engine with a throttle ring on it. Would that be better on a SPI set up?

duke.johnson wrote:Bernie
I just ordered the backplate last night. I was hoping to have a fast engine on a throttle for a C/L carrier plane. What would you suggest? Later, after proof of consept. I will want to build another with a TD. I have an engine with a throttle ring on it. Would that be better on a SPI set up?

Unfortunately, SPI and our rear-mounted throttle don't work well together as SPI negates the airflow restriction of the throttle. You will get idle speeds in the 10,000 RPM range with a 5x3 prop and, if that is low enough for you, then fine.

For SPI the throttle rings are better but there are reports that SPI and exhaust suppression are but a so-so setup.

Check if your engines actually have SPI or not. If yes, you can change the cylinder and have less power but a throttle or keep the setup and have more power but either no throttle, a cylinder ring or a throttle that does not idle super-low.

Ok, I think I got it now. I have other engines to put this on for the proto type. The real carrier plane needs to have a goo fast time and a good slow time. If I build the next one with a TD and add your TD throttle will I have a better set up?

Yes, the TD carb should work fine as it is the original carb that Cox used on the TD RC .50. However, please note that the TD RC operated on non SPI as that will work a bit better than a standard SPI setup. We have a limited # of non-SPI open-port cylinders left:

http://coxengines.ca/cox-.049-black-widow-cylinder-and-piston.html

SPI makes very little difference on TD engines (like 200 RPM).

Soooo, I just bought the choke tube throttle kit without the backplate to save money. I thought I had plenty of backplates to choose from, but the new throttle doesn't seat all the way against the backplate. The ones I have seem to all be black and the ventri is to big for the groove on the throttle. Has anyone worked with this? Can I modify the backplate? Or should I just breakdown and buy another backplate?

I've found the tube only fits well into the backplate made for it, might even have longer screws.

The choke tube was designed to fit the grey backplate but you should be able to fit it to the black backplate by cutting down the OD of the venturi hole of the backplate.

bernie

have you(or any other members here) used the TD carb , mounting it to the backplate of a reedie(like your choke tube throttle)??
the TD carb has better adjustments??(i have not seen one in person)
were the results better/different to the choke tube throttle?


cheers
a

Not the TD carb but one of our customers once made a carb prototype that went into the choke tube and sent it to us. It was too expensive to manufacture so we came up with our, more basic, version.

Since fuel is drawn through the spraybar, I can't see how a real carb version would work.

bernie

i was thinking, modify the reedie backplate,
remove and plug needle and fuel nipple holes
then use TD carb mounted either on chock tube(similar to yours)
or make adaptor and mount TD carb directly onto backplate opening

cheers
a.

Fly at it and let us know how it worked out.

bernie
i was so close to ordering one of those TD carbs from you a couple of days ago, when i ordered a choke tube throttle and some 010 parts.

now regretting i didnt
will have to finish a project before i start another

will be ordering a TD carb soon


cheers
a

Hey, we'll keep one warm for you here. Thanks for your business

ado1974 wrote:bernie

i was thinking, modify the reedie backplate,
remove and plug needle and fuel nipple holes
then use TD carb mounted either on chock tube(similar to yours)
or make adaptor and mount TD carb directly onto backplate opening

cheers
a.

Tarno made a reedie adapter for their carb: they occasionally turn up on ebay. Vaguely recall they had slightly different carbs for TD and reed engines. Location of throttle stop, maybe id??

Is this the right backplate for the throttle backplate? Then I could use the needle from another say black backplate? Cox Part#1258

Yes, the grey backplate is the correct one and you can use the brass needle from any other backplate.

Thanks. I need to see if we need anything else, then make the order.

Well, the boys and I flew the 1/2A carrier plane today before dinner. We put in about a dozen flights and things work ok. Needs a little work. I'm not sure if I have the right piston and cylinder. I bought the grey throttle back plate and if I remember right I should not ue te SPI cylinders, right? How do I tell if I'm using the right cylinder?

Any twin slit sure start cylinder should work as these did not have SPI. A #6 QZ cylinder or #8 cylinder would also work.

ahrma_581 wrote:

ado1974 wrote:bernie

i was thinking, modify the reedie backplate,
remove and plug needle and fuel nipple holes
then use TD carb mounted either on chock tube(similar to yours)
or make adaptor and mount TD carb directly onto backplate opening

cheers
a.

Tarno made a reedie adapter for their carb: they occasionally turn up on ebay. Absolutely correct. Vaguely recall they had slightly different carbs for TD and reed engines. Location of throttle stop, maybe id??

Not dure about thispart though,I never got one to do a chech against my TD tarno carbs.
There is still the old style ,simpler ACE reedie engine throttles to go another route too.