Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old Mar 19, 2006, 09:52 AM
Registered User
E-Challenged's Avatar
United States, CA, Garden Grove
Joined Oct 2000
11,752 Posts
Discussion
Sterling Stinson SR-8 Kit FS-33 57"+ Wingspan

Now that I have my old Berkeley 42" Stinson SR-7 kit conversion flying well, I started looking at my larger Sterling .40-56 glow size kit from the 70's. It looks as if the designer enlarged the ailerons and wing chord. Overall, the construction relies on lots of thick sheeting, solid balsa ailerons and tail surfaces. There are lots of opportunites for weight reduction. The Reliants are short nosed radial engine designs that will tend to be tail-heavy unless you plan ahead. This model with light weight brushless outrunner and lipo will probably need to have the lipo pack right up against the back of the firewall and all other R/C components placed as far forward as practical. Pull-pull on rudder and elevator will help. Looks like an AXI 2826 series or larger motor would be a good bet powered by a 3400-4000 mah 3 or 4S lipo pack. I think that the pack could be located in a vertical battery compartment behind the firewall, access from underneath for removal and replacement. It would be fun to build in flaps and program for down elevator as flaps are added for landing. I would build wing with no dihedral and expect to fly with aileron/rudder mix or manual mix. Two aileron servos on different channels would allow options for differential and throws and assure precise aileron control. This kind of model really needs a smooth paved takeoff and landing strip and enough room to maneuver safely. Just wanted to share.
E-Challenged is offline Find More Posts by E-Challenged
Reply With Quote
Sign up now
to remove ads between posts
Old Mar 19, 2006, 10:19 AM
Registered User
LesUyeda's Avatar
San Diego, California
Joined Dec 2004
3,341 Posts
I have battery location concerns also with my Waco. I don't want to have to turn the airplane on it's back to access, and I do want to have the capability of moving the battery as far forward as possible. It may not be clear, but I intend to have a sliding tray (green) in aluminum channels in the fuselage. The square blocks near the center line are fastened to the tray, the outer ones to the firewall. The pin is a 3/16 diameter aluminum tube. Pull the tube, slide the engine cowl/motor mount/battery tray out the front. If the ESC is also attached to this, the only wire connected to the aircraft will be the control line. Looks good on paper, we shall see!!.

Les
LesUyeda is offline Find More Posts by LesUyeda
Reply With Quote
Old Mar 19, 2006, 12:18 PM
Registered User
E-Challenged's Avatar
United States, CA, Garden Grove
Joined Oct 2000
11,752 Posts
Les, Hmmm interesting, it should work, guess you will use velcro on pack and tray. I have a battery box/compartment that protrudes through firewall in my 42" Stinson. Have to remove prop and ring cowl (cowl held on by velcro) to install and remove 1100ma 3S lipo pack.( I'm using Spektrum system so no problems with glitching and prop spinning up after I have installed and connected the pack). You might need an arming switch.I have a Guillows PT-17 with enough room to slide 400mah 3S pack into ring cowl past motor/gearbox without removing prop. I use another prop to loosen velcro to remove or insert pack.
E-Challenged is offline Find More Posts by E-Challenged
Reply With Quote
Old Mar 20, 2006, 07:39 AM
Big gov never Works
St. Martin's Avatar
Skunk Water, Rhode Island
Joined Jul 2002
12,301 Posts
This one is about 8yrs old. Was originally powered by a Saito .30 GK. Very nose heavy @ 48oz. Reason: Tail surfaces are laminat outlines and bilt-up. Silk on the fuselage, silkspan on wings and tail. This winter I changed it to "E" with a 28-x-x Axi. Not sure of the exact size. The plane balances with a 3s Hyperion 3700 20c pack, on the CG.

If you have not built one of these yet, (my 4th) ignore some of the Isometric drawings of the wing assembly. They show the wing being built flat with no washout. The wing will naturally build in it's own. Allow the parts to guide you. They are correct. Wt at this time is 44oz. I have two micro's in each panel for ail. Tail wheel is controled off the rudder linkage.

These are beautiful flyers, if the auw is kept around 4-5# or less. Any more and the tip stall will bite at low speeds. This one floats safely in. My first one wt was 6#(30yrs ago) Was not very friendly..

Steve
St. Martin is offline Find More Posts by St. Martin
Reply With Quote
Old Mar 20, 2006, 08:59 AM
Registered User
E-Challenged's Avatar
United States, CA, Garden Grove
Joined Oct 2000
11,752 Posts
Thanks for the good advice, some of these things are hard to predict with short nosed conversions. Does your SR-8 required some rudder with ailerons to turn or will it fly "yank and bank" well? The ailerons look quite enlarged from scale on the plans. My 42" Berkeley shows no tendency to snap but lands at a fairly brisk speed. The plane is more slippery than one would expect.
E-Challenged is offline Find More Posts by E-Challenged
Last edited by E-Challenged; Mar 20, 2006 at 09:04 AM. Reason: add info
Reply With Quote
Old Mar 20, 2006, 10:02 AM
Big gov never Works
St. Martin's Avatar
Skunk Water, Rhode Island
Joined Jul 2002
12,301 Posts
She will turn very good, wthout rudder. At higher speeds occourse. Slower speeds are nicer with very little rudder. That big rudder keeps the tail flying nicely in banked conditions. I flew this from a grass field. Even tho it was nose heavy, I only nosed over a few times. She is slippery. It was very fast with the Saito. I swung a 10-5 APC @ 12000rpm. Now she is lighter and is swinging a more efficient 10-7E prop at about the same rpm. I'm thinking of going to a 11-6E. Jus does not look right flying like a pylon racer.

Should you need any pics to aid in your build, I can take better pics outside. I took those in a hurry this morning.

Steve
St. Martin is offline Find More Posts by St. Martin
Reply With Quote
Old Mar 20, 2006, 02:19 PM
Registered User
E-Challenged's Avatar
United States, CA, Garden Grove
Joined Oct 2000
11,752 Posts
St Martin, You're probably not actually a saint but just a nice guy living in a strange place. I have an old 71" Sig J-3 cub project that I'll be working for a while before I start the Stinson. Have geared Astro 25 and 16 cell 1950AUP pack for the Cub.
E-Challenged is offline Find More Posts by E-Challenged
Reply With Quote
Old Mar 20, 2006, 04:02 PM
Big gov never Works
St. Martin's Avatar
Skunk Water, Rhode Island
Joined Jul 2002
12,301 Posts
Built a few of those, too.. Never electric, tho. Nicety is, the scale engine is not interfered by the I.C. engine.

Steve
St. Martin is offline Find More Posts by St. Martin
Reply With Quote
Old Feb 07, 2009, 12:17 PM
******fox
Yreka,CA
Joined Jan 2009
4 Posts
Hey Guys: just joined RC Groups So I could chime in on the subject of the Sterling Stinson fans. Been building since '47 and have a few favorites. It seems the Gullwing has more than it's share of enthusiasts. Benn flying rubber models of it ever since the Comet 25" kit came out. Picked up a Sterling kit in the '70's and just got it framed up (all things in time) and pretty well lightened for RC Electric. So far the complete frame, uncovered,stock landing gear and heavy wheels weigh 1lb., 13 oz. Motor may be the AXI 28 series which works well in my 2X Earl Stahl Mile Magister. (60" span.)

I was greatly enthused by the good flight reports from St. Martin and can already see , in my minds eye, this plane floating overhead. It may take wearing out a Dremel
to lighten the thing but that's part of the price.

Started using Solarfilm covering for the first time. The Monocoat used on the Miles Magister worked poorly. I'd been using Monocoat since the early '70's: this latest
batch shrinks less and is not so user friendly. Some minor wrinkles do not iron out. Solarfilm goes around corners very well and feels lighter. I'm sold.

Just bought four 16gram servos: put in two last night with nylon fishing line pull-pull
with crimped aluminum tubing to fasten. For you whom are to begin a kit: remember it was engineered to handle an engine and doesn't need the thick and heavy girders
and solid plywood for electric flight. I've been applying rubber model techniques to large electric models and get away with using small motors and batteries. Pat Tritle
is the master at this.

Good building to those on the Stinson Forum. All questions welcomed. Living in N. Calif
near the OR border. Building lots during the cold season.
George Popa is offline Find More Posts by George Popa
Reply With Quote
Old Feb 07, 2009, 02:41 PM
Big gov never Works
St. Martin's Avatar
Skunk Water, Rhode Island
Joined Jul 2002
12,301 Posts
Good luck, George! Mine met with disaster in July of "06". I was flying at a Fun Fly north of Old Saybrook, Ct. My first flight, with an EDF was glitchy, in one area. Like flying through a curtain. Then my TBF would not function properly. I should have stopped then. All my planes were on 72Mh, Ch 35. Their scanner showed no interferance.

So,. I put up the Stinson. After take off, flying over one section of the field, everything locked up. The old Stinson rolled in vertically. It's repairable, But I put it away for the future. Too many projects.

I was later told, by a few club members, that AT&T had a cable that ran under ground, in the area I was getting hit on both the Stinson and MiG-15. Nice time to tell me... They said they had in-frequent problems in that area, adjacent to the runway.

Oh well..

Fuzz
St. Martin is offline Find More Posts by St. Martin
Reply With Quote
Old Feb 07, 2009, 09:36 PM
******fox
Yreka,CA
Joined Jan 2009
4 Posts
For all you Stinson fans: there are tons of great full scale photos at www.stinsonreliant.com to find that one paint scheme to fit your taste.
Any Monocoupe 90A fans out there? We can start a new thread. Same Golden age
era as the Stinsons. While walking Shore Patrol duty in the Phillapines, I was partnered with a submariner with the last name of Stinson. Turns out his Great Aunt Katherine was a major player in the family business, and if memory serves, she gave flying lessons to Amelia Earhardt (Sp?) Small world, eh?
George Popa is offline Find More Posts by George Popa
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold Cool little "Cricket" Airplane Kit NIB ** 33"wingspan Joe Pierson Aircraft - Fuel - Airplanes (FS/W) 3 May 03, 2006 09:22 AM
Discussion Stinson SR-8 Where to buy?? pa2play Fuel Plane Talk 4 Mar 16, 2006 07:28 PM
Sterling Stinson Reliant SR-8 t-turley Scratchbuilt Indoor and Micro Models 0 Dec 03, 2002 07:29 PM
FS: Eco-8 kit, NIB GKurt Aircraft - Electric - Airplanes (FS/W) 2 Nov 08, 2002 02:12 PM
FS on Ebay: sterling stearman pt-17 KIT thexfiles Aircraft - Fuel - Airplanes (FS/W) 1 Oct 02, 2002 12:17 PM