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!


Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Babe_b10
Log in

I forgot my password

Search
 
 

Display results as :
 


Rechercher Advanced Search

Cox Engine of The Month
May-2020
Levent Suberk's

"Medallion .049"



PAST WINNERS
CEF Traveling Engine

Win This Engine!
Gallery


Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  Kim on Sat Sep 01, 2018 3:08 pm

Spent some time with my little Ryan ST-3, making up some test lines (I'll have it on 20 ft of Spiderwire when it flys) to check out the model's three line bellcrank/throttle system and also run a break-in on it's .020.

I just left it all together since it looked good from what I could see, and started it up.  It took a bit to get going, but ran steadily once it caught.  The bellcrank/throttle assembly worked great, but had little effect on the .020's RPM.  I'm gonna move the pushrod to the other hole on the sleeve's snap ring, to see if it helps...I remember having to slide the ring a bit on the sleeve of other throttles like this to get it to block enough exhaust to slow the engine.

I made an effort at explaining how the three-line works...probably clear as mud...but you take your shot.

It was strapped down all nice and comfy, so I let run for close to half an hour, doing refuels on the run, and enjoying my flash-back time.

So, now to cut some Spiderwire, and search for a nice smooth patch of asphalt!!

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 7_21

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 9_111

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 11_15
-----------------------------------------------
The trigger moves the flying lines in the opposite direction of the center throttle line.

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 8_410

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 8_510
-----------------------------------------------
Under the plane's belly, the bellcrank slides wingspan-wise, not affecting the elevator push rod, while the throttle push rod moves forward and backward.

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 8_113

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 8_210

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 8_311

----------------------------------------------------------
Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 11_6t10

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 11_910

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 V_1_10

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 V_1_210


Last edited by Kim on Wed Sep 05, 2018 12:49 pm; edited 2 times in total
Kim
Kim
Top Poster
Top Poster

2019 Supporter

Posts : 7166
Join date : 2011-09-06
Location : South East Missouri

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  MauricioB on Sat Sep 01, 2018 4:44 pm

Kim! ... that seems to be a challenge !!affraid surely we will have the opportunity to see him in action thanks to your efforts! cheers Thumbs Up
MauricioB
MauricioB
Diamond Member
Diamond Member

2020 Supporter

Posts : 2410
Join date : 2016-02-16
Age : 49

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  Cribbs74 on Sun Sep 02, 2018 8:11 am

Kim!!!

That’s just amazing, you are my new hero, can’t wait to see it fly! Thanks for the rundown on the 3 line system.

Ron
Cribbs74
Cribbs74
Moderator

2019 Supporter

Trusted Seller
Posts : 10802
Join date : 2011-10-24
Age : 46
Location : Tuttle, OK

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  Kim on Sun Sep 02, 2018 11:05 am

Thanks Ron!

I'm close to having an Air Force of Plastic RTF's and Balsa Control Liners ready to go...but we GOT to have break in this heat before I get out on that blacktop!

This little plane is one of my absolute favorites. When I got one back in the late 60's, I spent as much time taxiing as flying because of the (at the time) super novelty of having engine control on one of our planes.
Kim
Kim
Top Poster
Top Poster

2019 Supporter

Posts : 7166
Join date : 2011-09-06
Location : South East Missouri

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  ticomareado on Sun Sep 02, 2018 8:13 pm

Controls look a lot like a J. Roberts set up. I wonder if Cox paid royalties or a license fee.
ticomareado
ticomareado
Account Under Review

Posts : 1082
Join date : 2013-10-03
Location : NC

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  Kim on Sun Sep 02, 2018 9:11 pm

Yeah, I'd wondered about that. Aside from a bit of a change in geometry, they're pretty much the same thing, and also for the handle. Wonder if Larry Renger would have any idea.

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 1_32

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 2_36

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 3_27

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 4_25

Wen Mac had a little different approach...check out that line spacing!

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 5_19

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 6_18

Kim
Kim
Top Poster
Top Poster

2019 Supporter

Posts : 7166
Join date : 2011-09-06
Location : South East Missouri

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  MauricioB on Sun Sep 02, 2018 11:12 pm

Ohh Kim ... I'm from the other side of the world and I thank you for all this information! ... it's nice to know the part of the history of each of the manufacturers! ... thanks for sharing here! cheers
MauricioB
MauricioB
Diamond Member
Diamond Member

2020 Supporter

Posts : 2410
Join date : 2016-02-16
Age : 49

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  Kim on Mon Sep 03, 2018 5:36 am

MauricioB wrote:Ohh Kim ... I'm from the other side of the world and I thank you for all this information! ... it's nice to know the part of the history of each of the manufacturers! ... thanks for sharing here! cheers

You're welcome Mauricio! Thanks to the internet, and this forum in particular, we care share all this great activity with those who also appreciate it!
Kim
Kim
Top Poster
Top Poster

2019 Supporter

Posts : 7166
Join date : 2011-09-06
Location : South East Missouri

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  rsv1cox on Mon Sep 03, 2018 6:51 am

Huge cuteness points on that ST-3 Kim.  It grabs me like few other Cox models.

There is one on ebay right now, but it's used and lacks the decals which really adds pizazz.  Another NIB on Worthpoint? a member only collectors auction site.  

Bob

PS: I love the tethered engine running photos.
rsv1cox
rsv1cox
Top Poster
Top Poster

2019 Supporter

Posts : 5230
Join date : 2014-08-18
Location : West Virginia

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  Kim on Mon Sep 03, 2018 6:57 am

rsv1cox wrote:Huge cuteness points on that ST-3 Kim.  It grabs me like few other Cox models.

There is one on ebay right now, but it's used and lacks the decals which really adds pizazz.  Another NIB on Worthpoint? a member only collectors auction site.  

Bob

Back in the 1960's, one of my heroes, Dave Thornburg---mostly known for his Bird of Time Sailplane---published a free slight version of the ST-3.  It was powered by a Pee Wee .020, and was larger than the RTF, but could be resized down by someone wanting the cuteness without taking out a bank loan.  

I'll scan his plan sheet and article and post it when I find it.
Kim
Kim
Top Poster
Top Poster

2019 Supporter

Posts : 7166
Join date : 2011-09-06
Location : South East Missouri

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  getback on Mon Sep 03, 2018 7:36 am

Very Cool ! That's a nice looking plane there . I see how it works but let me ask once you pull the throttle wire how does it get bac to were it was ? Is it in the controls up or down? Thanks  Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 8_21010
Bee watching for the flight when the time is right Hot  here too !!
getback
getback
Top Poster
Top Poster

2019 Supporter

2020 Supporter

Posts : 6975
Join date : 2013-01-18
Age : 62
Location : julian

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  Kim on Mon Sep 03, 2018 8:40 am

getback wrote:Very Cool ! That's a nice looking plane there . I see how it works but let me ask once you pull the throttle wire how does it get bac to were it was ? Is it in the controls up or down? Thanks  Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 8_21010
Bee watching for the flight when the time is right Hot  here too !!

I'll take a shot at it and try not to be TOTALLY confusing...with a scribble that may REALLY confuse things.  

First, think of a mounted bellcrank with a pushrod that runs forward to the throttle band.  It has only one leadout line attached, going back to the center connection on the handle.  Now imagine ANOTHER bellcrank, mounted in the remaining lead-out hole of the first.  

As the throttle trigger on the handle is operated, it moves only the Throttle Bellcrank (the two flying lines work as one when this happens), while the entire Elevator Bellcrank just moves spanwise, with no input to the elevator push rod.

When the handle is tilted up or down, only the Elevator Bellcrank is rotated, with no affect on the power output of the engine, because the throttle line is attached to the center of the handle, thus the center of the handle's pivot.

Hope this is somewhat understandable.  I've got video of the bellcrank in operation, but was gonna save it to add to the flight video.

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 0_212
Kim
Kim
Top Poster
Top Poster

2019 Supporter

Posts : 7166
Join date : 2011-09-06
Location : South East Missouri

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  getback on Mon Sep 03, 2018 11:59 am

Thanks for going to that trouble to help me understand , I think I got it now!! This Site Rocks!
getback
getback
Top Poster
Top Poster

2019 Supporter

2020 Supporter

Posts : 6975
Join date : 2013-01-18
Age : 62
Location : julian

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  Kim on Wed Sep 05, 2018 12:47 pm

Found this article and scanned it in case anyone here might like to create their own balsa Ryan St-3.  Normally, I knock down the size of scans and photos to make them easier to load, but I loaded large-scale files for this one in hopes that the text might be easily readable.

The article and plan are from the November, 1968 Edition of Flying Models, and MAY be on Outerzone, but I haven't checked.

I know it's a profile model, but a determined builder ought to be able to turn it into a full-body without too much effort.  Building it as-is is one of my 'Some Day Projects' as I stared it with some intensity back in the day, and am also a big fan of Dave Thornburg.

Take the scale down to fit an .010, and you'll have to hide it to keep it from being planenapped!!!

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 0_14

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 1_33

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 2_37

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 3_28

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 4_26

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 0_14
Kim
Kim
Top Poster
Top Poster

2019 Supporter

Posts : 7166
Join date : 2011-09-06
Location : South East Missouri

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  Dave P. on Wed Sep 05, 2018 2:19 pm

Thanks for that explanation of the three line throttle system Kim! I've always wondered how those work. One more question though, is the throttle tensioned by line tension to stay at full throttle (or idle?) unless the trigger is pulled / pushed, or does one have to physically move it in both directions?

Dave P.
Dave P.
Gold Member
Gold Member

2020 Supporter

Posts : 457
Join date : 2017-07-31
Age : 62
Location : Durham, NC

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  Kim on Wed Sep 05, 2018 4:27 pm

Dave P. wrote:Thanks for that explanation of the three line throttle system Kim!  I've always wondered how those work.  One more question though, is the throttle tensioned by line tension to stay at full throttle (or idle?) unless the trigger is pulled / pushed, or does one have to physically move it in both directions?


It's tensioned by the same force that works on the flying lines---the plane's outward force. It's controlled totally by the trigger position on the handle, which can go anywhere in it's power-curve. As the center connection moves in, the two flying lines move out and vice versa. In this way, it is acting exactly as an elevator bellcrank, with no springs needed: The flying lines' bellcrank being on one side of the throttle's bellcrank, and the center line being the other.

The flying lines have their own bellcrank, which doesn't really care what the throttle position is....crap, that looks/sounds confusing! I promise to do an up-close video of it working. It's not NEARLY as complicated as my writing would suggest.

I THINK there once was a throttled Cox model with a spring attached to the throttle band on the plane and a 'thumb button/wire' fitted in the notch on the top of a typical Cox Handle. The line was threaded from this wire button, out to the plane, and forward to the throttle band. Push down on the wire button, which pulls the string, which pulls the throttle open, and the spring pulls it back closed when pressure is let off the button.

I remember having the handle but, like so many other things, the rest is pretty fuzzy!



Kim
Kim
Top Poster
Top Poster

2019 Supporter

Posts : 7166
Join date : 2011-09-06
Location : South East Missouri

Back to top Go down

Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68 Empty Re: Cox Ryan ST-3 & Dave Thornburg's Ryan ST...FM 11/68

Post  Sponsored content


Sponsored content


Back to top Go down

Back to top


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