Cox Engines Forum
You are not logged in! Please login or register! Guests are limited to posting in the "General Questions (Guest Posting Allowed)" section only. Becoming a member is fast, easy and FREE!


Acceleration Control Ring. Babe_b10
Log in

I forgot my password

Search
 
 

Display results as :
 


Rechercher Advanced Search

Cox Engine of The Month
August-2019
fredvon4's

"Tee Dee .049"



PAST WINNERS
CEF Traveling Engine

Win This Engine!
The Traveling Prop
Gallery


Acceleration Control Ring. Empty
World of Aviation

Acceleration Control Ring.

Go down

Acceleration Control Ring. Empty Acceleration Control Ring.

Post  MauricioB on Mon Jun 03, 2019 2:02 am

Something simple, but so effective.
Very few pieces, optimal result.
Applicable to almost all Cox engines.
I admire the IDEA of the * Acceleration Control Ring *
So my question:
Anyone know, who was born the idea of the Acceleration Ring?
Was it some specific Cox staff? ...
I would feel very good if a friend can tell me the story of this great invention! Clapping Clapping
Thank you.
MauricioB
MauricioB
Diamond Member
Diamond Member

Posts : 2083
Join date : 2016-02-16
Age : 48

View user profile

Back to top Go down

Acceleration Control Ring. Empty Re: Acceleration Control Ring.

Post  ticomareado on Mon Jun 03, 2019 6:43 am

The basic idea and execution of an exhaust restriction throttle of one sort or another on the single collected lateral exhaust of glow model engines preceded any Cox effort by several years. The ringed exhaust restrictor was simply a refinement/adaptation to work with Cox's cylinder design. (and Cox's set up did indeed work considerably better) In the sub-miniature class engine category, the Anderson/Jim Walker Spitfire .065 and Wen Mac MK II .049s came out with lateral exhaust collector throttle restrictors before Cox did its "ring thing". AMF Wen Mac also came out with a "ring thing" throttle restrictor for use on its glow head Hot Shot series engine powered Lotus race car and Boeing Pea Shooter plane. (circa 1965) This throttle is also very effective, though I don't like the mechanics of its linkage system which needs hacking for practical use on a built R/C plane. I'll leave it to others to say who was first with the "ring thing".
ticomareado
ticomareado
Platinum Member
Platinum Member

Posts : 727
Join date : 2013-10-03
Location : NC

View user profile

Back to top Go down

Acceleration Control Ring. Empty Re: Acceleration Control Ring.

Post  ticomareado on Mon Jun 03, 2019 12:36 pm

My quickie research of archives and Hepperle suggests that Cox's first use of a "Ring Thing" throttle was circa 1969 on the Medallion R/C and then the early seventies on 190 and 290 series product engines. So AMF Wen Mac may have beat them to it circa 1965 Hotshot powered Boeing Pea Shooter and Lotus race car.
ticomareado
ticomareado
Platinum Member
Platinum Member

Posts : 727
Join date : 2013-10-03
Location : NC

View user profile

Back to top Go down

Acceleration Control Ring. Empty Re: Acceleration Control Ring.

Post  balogh on Tue Jun 04, 2019 12:11 am

Having played with various COX RC and Tarnot RC carbs as well as with exhaust throttle rings, my experience shows the exhaust throttle ring provides the better rpm control, and if throttle ring is used and the stock carb remains on the engine the top rpm achievable with the stock TD carb is higher than with RC carb  thanks to  the more perfect atomization of fuel in a stock  COX carb than in a COX RC or Tarnot carb...let alone the poorer fuel suction with the unscreened RC carbs. On top of this, no special glow head with hot plug to reach low and stable idle is required with the use of exhaust throttle ring.

So I tend to swap my RC carbs with stock carbs and use exhaust throttles instead, that are visually less appealing/elegant but work better for me. Maybe out of some nostalgia I will reswap them sometime soon but now I am having my exhaust throttle ring period.. Very Happy

The only downside of exhaust throttle rings is some have caused excessive abrasion on the lowermost cylinder cooling fin that finally detached. Maybe the vibration..To prevent this I bend a thin ring from a servo  pushrod/ piano wire and pull it on the cylinder up to the lowermost fin to protect the fin from the continuous abrasion by the ring vibration..with a thin enough  wire the throttle ring height is still OK..if not, the bottom of the ring is sanded a bit so that the ring should not get stuck when the cylinder is tightened in the crankcase.

Sorry that my post missed the historical details.
balogh
balogh
Diamond Member
Diamond Member

Posts : 2365
Join date : 2011-11-06
Age : 60
Location : Budapest Hungary

View user profile

Back to top Go down

Acceleration Control Ring. Empty Re: Acceleration Control Ring.

Post  KariFS on Tue Jun 04, 2019 2:22 am

Andras, I think some mufflers have a kind of a ring you described, made of a rather "soft" wire.

I don't have much history data either, but I suppose that with the SPI the exhaust throttle works better than a "standard" R/C carburetor. The SPI would act the same way as an air leak in a manifold when the throttle is not in its wide open position.
KariFS
KariFS
Diamond Member
Diamond Member

Posts : 1539
Join date : 2014-10-10
Age : 47
Location : Finland

View user profile

Back to top Go down

Acceleration Control Ring. Empty Re: Acceleration Control Ring.

Post  MauricioB on Tue Jun 04, 2019 11:15 am

Thanks for all the data and opinions ... very interesting!
A particular piece that we use often and becomes common among us, to think for a moment, who or who were his / her creators of this idea, is really great.
I really enjoy the Cox r / c engine models, and that piece is incredible, it works, and it works excellently.
Thanks to that idea, I was able to control my Cox .010 ... and I enjoy it very much! Thumbs Up
Ticomareado: very interesting those stories Thumbs Up
MauricioB
MauricioB
Diamond Member
Diamond Member

Posts : 2083
Join date : 2016-02-16
Age : 48

View user profile

Back to top Go down

Acceleration Control Ring. Empty Re: Acceleration Control Ring.

Post  balogh on Tue Jun 04, 2019 11:54 am

KariFS wrote:Andras, I think some mufflers have a kind of a ring you described, made of a rather "soft" wire.

I don't have much history data either, but I suppose that with the SPI the exhaust throttle works better than a "standard" R/C carburetor. The SPI would act the same way as an air leak in a manifold when the throttle is not in its wide open position.

Thanks Kari yes I observed the inefficient throttling by RC carbs on SPI engines and figured the same reason behind it as you described.

Because for performance reasons I prefer SPI to non-SPI, this is another reason why temporarily I concentrate on exhaust throttle rings and put my RC carbs away a for bit of time.
balogh
balogh
Diamond Member
Diamond Member

Posts : 2365
Join date : 2011-11-06
Age : 60
Location : Budapest Hungary

View user profile

Back to top Go down

Acceleration Control Ring. Empty Re: Acceleration Control Ring.

Post  ticomareado on Thu Jun 06, 2019 8:40 pm

Peter Chinn discusses Wen Mac Hot Shot .049 with "ring thing" throttle in June 1965 M.A.N. review, so I guess Wen Mac was first to mass produce an .049 "ring thing" throttle.

http://sceptreflight.com/Model%20Engine%20Tests/Wen%20Mac%20.049%20Hot%20Shot.html
ticomareado
ticomareado
Platinum Member
Platinum Member

Posts : 727
Join date : 2013-10-03
Location : NC

View user profile

Back to top Go down

Acceleration Control Ring. Empty Re: Acceleration Control Ring.

Post  MauricioB on Thu Jun 06, 2019 9:33 pm


Excellent information!. It is very possible then that the system of acceleration by means of the ring is of Wen Mac and that its initial date is the decade of 60.
Thanks Ticomareado. It is good to know the history of beautiful and useful inventions! Clapping
MauricioB
MauricioB
Diamond Member
Diamond Member

Posts : 2083
Join date : 2016-02-16
Age : 48

View user profile

Back to top Go down

Acceleration Control Ring. Empty Re: Acceleration Control Ring.

Post  Sponsored content


Sponsored content


Back to top Go down

Back to top

- Similar topics

 
Permissions in this forum:
You cannot reply to topics in this forum