Author Topic: Questions: Nobler w/S35 (Read 2918 times)

Scott Hartford · « **on:** August 05, 2009, 08:59:34 PM »

OK, so I am trying to build a Nobler that is very light, hopefully the first number won't start with a 4, and I am going to use a good OS 35S. It's been a while since I have used one and can't remember how much fuel it used. So question #1: What size tank? I have a good 3.5oz. uniflow laying about.
While I'm at it, what would be a good starting prop? Now for the goofy part, I am not going to have flaps on this one. I figure light construction could benifit from the loss of 2 ball links, 2 bolts and nuts, 2 pushrod ends, a short pushrod, flap horn and bushing stays, and 8 hinges. How do you think a light flapless Nobler will fly?

?

Wynn Robins · « **Reply #1 on:** August 05, 2009, 10:27:15 PM »

from what I have read about Noblers - light flapped ones do not fly very well - they have to be a certain weight or above - not sure if my memory is right - but I think anything under 38oz on the flapped version fly badly.

now a flapless one would be interesting - you can be sure it wont turn as well as the flapped version.......

Tom Weedman · « **Reply #2 on:** August 05, 2009, 11:57:52 PM »

4 o/z tank 10-6 rsm or brodak prop that works on mine well
tom weedman AMA 63672

Larry Fulwider · « **Reply #3 on:** August 06, 2009, 05:31:23 AM »

Quote from: Scott Hartford on August 05, 2009, 08:59:34 PM

. . . Now for the goofy part, I am not going to have flaps on this one. . . .

Well, you know folks are going to ask, "Why not?"

I assume you have something in mind other than the weight savings?

Larry Fulwider

Matt Colan · « **Reply #4 on:** August 06, 2009, 06:25:59 AM »

I've heard a Nobler won't fly good if it is under 40 ounces, but now no flaps, hmmm, don't know about that. My OS 35 runs over 7 minutes on a 4 ounce tank. An RSM 10-6 is a good prop to start with.

Scott Hartford · « **Reply #5 on:** August 06, 2009, 06:45:01 AM »

Quote from: Larry Fulwider on August 06, 2009, 05:31:23 AM

Well, you know folks are going to ask, "Why not?" I assume you have something in mind other than the weight savings?

Larry Fulwider

I am not totally convinced that it will need flaps at a light weight, so I gotta find out!

I'll see your Why Not and raise you a Why?

phil c · « **Reply #6 on:** August 06, 2009, 07:16:14 AM »

The Nobler has about 550 squares. If you can build it around 34 oz. or less it will fly just fine with fixed flaps. The turn radius in the square maneuvers will be about the same as a flapped version that weighs 45 oz.

Since your experimenting, you might want to look into downunder's adjustable flap linkage. He added a little hardware to the bellcrank pivot wire that allows adjustment of the flaps from 0deg. movement up to about 35 deg. Very light planes require a lot less flap than a 1:1 linkage gives. The extra nose down force from the excessive flap movement actually makes the plane turn in a nose-down attitude.

Robert Zambelli · « **Reply #7 on:** August 06, 2009, 07:29:02 AM »

I cannot comment about a flapless version but when I built my Brodak Nobler at 34 ounces it was TERRIBLE.

During a conversation with George Aldrich, I mentioned how disappointed I was in the performance, describing exactly how it performed.
He stated "It weighs around 35 ounce, right?"
Explaining further, he said that the Nobler weight should always be above 40 ounces for decent performance, especially in the wind. He said he flew some that were nearly 50 ounces and they performed very well. He also mentioned that the best power setup was a stock Fox 35 with a 4 ounce over/under two-vent tank setup. He said that he definitely did not like uniflow.

I did some refinishing and added some nose and tailweight, bringing the total weight to around 44 ounces. UNBELIEVABLE difference. It flew exactly as I expected it to - smooth groove, no jumping or over control. I am completely pleased with the plane and really enjoy flying it. In capable hands, I'm sure it would bring lots of gold in Classic Stunt.

Bob Z.

ps - I'd listen to Phil C. I've flown his flapless planes and I was amazed at the performance.

phil c · « **Reply #8 on:** August 06, 2009, 07:34:24 AM »

Picture of Brian Hampton's adustable linkage from SS:
http://www.clstunt.com/htdocs/dc/user_files/15254.jpg

Scott Hartford · « **Reply #9 on:** August 06, 2009, 08:15:29 AM »

That's neat! I was thinking that with light weight, flaps may be counter-productive, so I will try flapless. I can't really see why it wouldn't work OK. Sure would be easier to trim!

Balsa Butcher · « **Reply #10 on:** August 06, 2009, 08:18:13 AM »

I've never had to use more than 3.5 ounces to get a pattern with an OS-35S...that being said, I would still go with a 4 ounce tank if it were my plane. Great engine, should be a good combination, with or without flaps.

Garf · « **Reply #11 on:** August 06, 2009, 10:00:02 AM »

I have an ARF Nobler with an OS 35S with an aftermarket ABC P&C installed. I installed a 5 1/4 oz rectank converted to clunk and use around half a tank to do the pattern with about 2 minutes left over at the end.

john e. holliday · « **Reply #12 on:** August 06, 2009, 11:29:13 AM »

Why change a winner. No telling how many trophies across this great land of ours have been won with box stock Noblers. And they do fly great in 40+ ounce range. DOC Holliday

Scott Hartford · « **Reply #13 on:** August 06, 2009, 11:36:34 AM »

I have other Noblers in the 40 something oz. range and one in the "lets not talk about it" range, and they fly great, so I just want to try something different. It ain't easy bein' me......

john e. holliday · « **Reply #14 on:** August 06, 2009, 11:38:43 AM »

Well go with it and let us know the results. Having fun, DOC Holliday

Will Davis · « **Reply #15 on:** August 06, 2009, 06:01:26 PM »

Scott,

The fuel consumption on the 35s will rely alot on the venturi size , oil content of fuel, whether you run a deep 4 cycle/ high pitch prop or in a mild 2 stroke with a low pitch prop, ( Not recomended for long engine life ) .

I use a stock 35 s in a Classic design, a little smaller than a Nobler with a .265 venturi. S/T NVA 10.25 / 6 Bolly Prop Powermaster 22% 1/2 Castor fuel. A little light on the oil for a 35 s, but it runs great .. Takes 3.25 ounces of fuel .

Same Engine / Plane , Bigger venturi, 24% all castor Sig .. it will use 4 ounces .

Go ahead and try the unflapped Nobler, will be good to see how it works out ..

Will

Bill Little · « **Reply #16 on:** August 06, 2009, 06:13:37 PM »

I agree with Will. A LOT will depend on *your* engine and how you run it. I know a good 35S can use from 3 1/2 oz. to 4 1/2 oz. depending on fuel, location, etc..

A 10-5 or 10-6 (known pitch) is a starting point. I found all of mine, in this area, to run well on 10-5 props (Some of those props were marked as *6* pitch, but weren't) and 5%-10% nitro, 25% all castor fuel. 10% nitro took a touch over 4 oz. to get cleanly through the pattern. On 5% I could take some out of a 4 oz. tank.

Bill Hummel said he spent all summer trying to get his 35S to run like mine, but mine was just box stock.......... and on a profile!

Mongo

Scott Hartford · « **Reply #17 on:** August 06, 2009, 08:46:28 PM »

Great info guys! My 35S has a .265 venturi and stock needle valve and a tongue muffler. I had planned to run 10-29 fuel. I have some RSM 10-6 props. I guess I will get a 4 oz. tank. Which one would be best? It slides in from the front like an arf nobler.

Garf · « **Reply #18 on:** August 07, 2009, 09:22:48 AM »

Be careful about running high oil content fuel in that engine. When I did that to mine, I started to get unexplained flameouts. I went to 20% oil fuel and the problem went away.

Clint Ormosen · « **Reply #19 on:** August 09, 2009, 10:38:36 PM »

Sorry Scott, but I have to say I think you're setting yourself up for a disappointing model. to start with, good luck getting the airplane down to 34 ounces. Even without the hardware for movable flaps, you're going to have to build the model out of pretty punky wood and skimp a lot on epoxy and fillets and such. The finish is going to have to be minimal as well. Even if you do manage to get it down to the 34oz range, I still don't think it will turn a corner as well as a flapped 42 oz Nobler. Or fly as stable for that matter.

Just my opinion. I think you'd be better off designing you own flapless model.

Robert Zambelli · « **Reply #20 on:** August 10, 2009, 05:56:36 AM »

Garf wrote: "Be careful about running high oil content fuel in that engine. When I did that to mine, I started to get unexplained flameouts. I went to 20% oil fuel and the problem went away."
I had the EXACT SAME thing happen to mine when running 25% all castor. The piston became so varnished that it bound at TDC and would quit at the oddest time. I lapped it with rotten stone, switched to 22% 50/50 and it never misbehaved again.
And, of all the engines I've ever owned, I found the Max S35 the most sensitive to venturi diameter. As I recall, .270 worked best for my application.

Bob Z.

James C. Johnson · « **Reply #21 on:** August 10, 2009, 08:03:07 AM »

Quote

switched to 22% 50/50 and it never misbehaved again.

I have had the same experience.. many of us were told to always use lots of castor.. I certainly took that recommendation to heart.. when growing up I used Super Fuel, Duke's, K&B 100 and 500.. and I ran with no muffler.. and never had flame outs, then when I started using a muffler (Slimline).. the troubles began. I had an old Enya 35 that would burn anything and just keep on chugging.. the OS was finicky.. but the run was fabulous.

When I started using Super Cool RC (pink) fuel because that was all I had locally with castor added the engine started running great.. the solution was to use less oil.. 22% seems to be OK ... I like this engine because it takes a wide range of props.. unlike the FP-LA APC thing today.. I hate APC props.. mostly the way they fit to a spinner.. but I have to admit, they run great.

My OS 35s have used 3.5 tanks with a .280 venturi and run perfectly, in the 7 minute range depending on how rich or lean the run is.. I use a 4 oz plastic RC tank these days and measure the fuel. I still use metal tanks on profiles.. I like that "look" .. The Fox 35 will varnish up the same way as the OS... I use 25% oil in my Fox's ..

This is a great engine to experiment with.. I have about 15 of them and it is one of my favorites.

Jim