Throttle/muffler - RC Groups
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Sep 19, 2017, 10:11 AM
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Paul_BB's Avatar
Discussion

Throttle/muffler


Hi,

A French friend of mine is testing a new kind of throttle/muffler for Cox .049. It is made with a 3D printer. The material is epoxy (250). The ring does not turn around the cylinder, but has a valve (green part on the second pic) that regulates the exhaust gases.

He told me the power loss is very small.

Anyone interested? He could launch a small series.
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Sep 19, 2017, 10:20 AM
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xplaneguy's Avatar
Paul - I'm interested! How much testing has been done to determine how the epoxy material holds up over time? Any idea what the price will be?

Thanks,
Tony
Latest blog entry: Evelyn's first Cox PT-19 flight
Sep 19, 2017, 10:34 AM
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Paul_BB's Avatar
Quote:
Originally Posted by xplaneguy
Paul - I'm interested! How much testing has been done to determine how the epoxy material holds up over time? Any idea what the price will be?

Thanks,
Tony
Hi Tony,

My friend has build only one prototype some time ago just to test a 3D printer at his workplace (if my understanding is right). He said the throttling was great but the ring broke after 10 cycles because it was fitted too tightly around the cylinder.
He is ready to try to solve the problem (he has an idea on how to proceed) if people are interested.
He is a mechanical engineer working at Turbomeca, a helicopter turbine manufacturer in SW France. He is very good and every modeler here in France knows him (he designed a few of models). His name is Franck Aguerre. He also wrote a book on the basics of model airplane design.

I asked him to give us an idea of the price.
Sep 19, 2017, 11:29 AM
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coriolan's Avatar
Quote:
Originally Posted by xplaneguy
Paul - I'm interested! How much testing has been done to determine how the epoxy material holds up over time? Any idea what the price will be?

Thanks,
Tony
You can contact him directly at Jivaro models:
http://www.jivaro-models.org/homepage/homepage.htm
franck.aguerre@jivaro-models.org
Or send him a pm (He's a RCG member)
https://www.rcgroups.com/forums/member.php?u=65760
Sep 20, 2017, 12:16 AM
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Paul_BB's Avatar
Franck told me that the throttling is as good as that of the new device below but his muffler is more effective (less noise and more power due to the baffles in the muffler). And you don't need an external fuel tank.
Sep 20, 2017, 12:27 AM
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Paul_BB's Avatar
And look at what Franck is working on now... This guy is incredible.

All the parts have already been machined.
Sep 20, 2017, 12:39 AM
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Amp Abuser's Avatar
He could mass produce not assembled and folks supply their own Cox pistons and cylinders
to finish the kit.
Sep 20, 2017, 01:05 AM
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Paul_BB's Avatar
His work is inspired by Ralf Barnette:
https://www.rcgroups.com/forums/show...ylinder-Radial
Sep 20, 2017, 09:34 PM
Registered User
That is a slick muffler / throttle setup. I would buy a few to try them out.

Keep us informed as Franck adjusts / modifies them to last. I would love to see one developed for the TD .049 / .051 as well.

Brian

Brian
Sep 21, 2017, 12:04 AM
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Paul_BB's Avatar
Quote:
Originally Posted by av8rsodt
That is a slick muffler / throttle setup. I would buy a few to try them out.

Keep us informed as Franck adjusts / modifies them to last. I would love to see one developed for the TD .049 / .051 as well.

Brian

Brian
Hi Brian,

I'll keep you informed.

Paul
Sep 22, 2017, 07:49 AM
Registered User
Never saw one of Barnette's engines develop enough power to fly a plane very well. He would bring these designs to SMALL and work on them for days.
Sep 22, 2017, 11:59 AM
Registered User
Wow! that all could have been an Awe inspiring Sellout in 1975!
Today, Norvels (or current equiv Name) Throttle V nicely .. thank you
IMO...even IF one wanted a 2 stroke radial ?
Sourcing several New NOS (not repro) Cox cyls/pistons might be a bottleneck
Sep 22, 2017, 12:18 PM
Registered User
The throttle in post #5 was really more of a choke than a throttle, so anything may be better than that. It will slow the plane down enough to fall out of the air, as reedies are not real balls of fire anyway. Ya long live Norvels!! (NV) Oh, and AP .09 / .15s. for the $$/fun ratio.
Sep 23, 2017, 12:20 AM
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Paul_BB's Avatar
Thanks for the comments. I think Franck is just having fun.
Sep 23, 2017, 01:58 PM
Registered User
If it is fun, then there will have to be a tax on it. As you can tell, I am not a fan of reedies except the .074 and Sportsman. That muffler would salvage a few of my TDs. We can not fly at my club without a muffler here ore a means to shut off the motor. I just use the Norvels though.


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