Noblarf complete!

I finished my Noblarf and plan to try it out tomorrow.

It came out 38 ounces, and seems to balance just ahead of the spar, which should be good enough for starters.

Power is an OS 25 fp running backplate pressure and the standard FF venturi. Tank is a 4-ounce Hays. I put a check valve in the pressure line, then a T-connecter to allow me to use the same line for filling. Two vents to the outside that are then sealed to each other for flying.

Replaced the main wheels, and of course I put eyelet bushings in the bellcrank and new lead-outs, then a ball joint BC to pushrod connector. The tail wheel wire was replaced with a longer one that centers the tailwheel. Slightly heavier gauge, too.

Another item added was a shield to limit the airflow into the bottom rear of the cowl. For some reason the tank compartment and remainder of the plane are wide open to junk spraying off the engine. If you have a slightly loose front bushing, and there is some crankshaft blowby, you will get an oil-soaked model!

Prop is an undercambered, customized 10x4 that started out in life as a Zinger, but saw the light. If anyone is interested, I can give a rundown on how to turn a Zinger into a real propellor. Trostle and Jim Armor have run these props and think they work pretty well.

For reasons that escape me, I can't upload photos from home, so you will have to wait 'till after New Years to see the "before" photos. (With luck, the "after" photos will look the same.....) Uploading from work seems to work just fine. Leonard ......HELP!!!!

Larry Renger
think S.M.A.L.L.

Larry! Good to see you finally "moving up" to something larger than .049...

Tim

>Prop is an undercambered, customized 10x4 that started out
>in life as a Zinger, but saw the light. If anyone is
>interested, I can give a rundown on how to turn a Zinger
>into a real propellor. Trostle and Jim Armor have run these
>props and think they work pretty well.

Larry,

I'm up for a rundown of how to turn a Zinger into a Winner!! *groan*

Thanks for the other info on NoblARF mods.
Santa bought me one but unfortunately he didn't put it together for me!

Peter O'Keeffe

Hey Larry - Santa brought me one too! Send me an email with some of your experiences on how you changed out the Bellcrrank, etc. Looks tight to me. I want to make the thing as curable as possible - my stunting machines are wrung out after a season of competition! And so am I! LOL
Thanks,
Joe.

The key elements to correcting the leadout and bellcrank were to replace the leadout material with .021 or larger cable, and put brass eyelets in the bellcrank holes to eliminate wear. Then I used the Du-Bro 4x40 trapped ball-link end bolted to the bellcrank (catalog #497) and then soldered the provided clevis to the other end of the flap pushrod to go to the flap control horn. This raises the front pivot ponint of the flap rod, and evens out the control a bit.

I thought the elevator pushrod was just fine as provided, but a horrible thought just occured to me. I am seeing insides more open than outsides, and believe me, that model is set up EXACT! I am wondering if the elevator pushrod is flexing on insides, and being in tension, working just fine on outsides. Gloom. Fixing that, at this point, is going to require some messy surgery!

BEWARE!!!!

Another trick was to cut the inboard flap short just outside the outside hinge, and use heavy copper wire to retain the remaining piece as a trim tab. This helps reduce the hinging due to the excess size of the inboard wing and flap. So far, it seems to be working!

Larry this the first Nobler I have heard of with a 25 will be interesting to know how it flies. Just finished my second Nobler ARF , trim is Rustoleum, and even put a pilot in this one . The power is a OS 35 S from GMA . The only problem I have ts trying to keep the wrinkles out. My Daughter received a new Camera for Christmas so I hope we can start to post pictures. See ya Neal:)

Flew it two times today. Limited it to that because I wanted to adjust the flap/elevator setting to get the insides to match the outsides. I also think I will need some tailweight.

Level flight is smooth as glass, upright and inverted. <G>

On 58.5' x .015 cable, this thing is trying to rip my arm off! I didn't time laps, but I expect they are under 5 seconds. I plan to go to .012 solids x 62'.

I have been having trouble posting photos to SSW from home, and am working on that. It will be next week before I am at work, where posting works just fine. (strange????)

Zingers are exellent prop kits. Good wood and lots of it to work with. The key changes are to add undercamber and Phillips entry (a bit of upcurve on the underside below the leading edge), a ROUNDED leading edge, a thin trailing edge, move the high-point of the airfoil to 33% from the 45 or 50% position that is provided, and thin the blades. Basically, you are taking a propellor blank and airfoiling it with a good, low Reynolds Number airfoil.

If you are using a big spinner, it is easier, as you have little work to do at the hub. Otherwise, you have a LOT of work to do at the hub.

First off, I work the underside of the prop. I draw a circle on top and bottom of the hub to give me reference for how far in I need to re-contour. Then, I rework the hub area to match a helical surface in as far as the circle with a nice smooth fillet to lead in from the hub to the blade bottom.

Next, I draw a line at about 10% chord from the leading edge, and then lightly bevel that part upwards about 5 degrees. Just enough to see. Now the magic part! If you angle a cutter (I use those Tungsten Carbide round rods you can get from Micro-Mark) outward from leading edge to trailing edge about 45 deg, it will automatically cut in undercamber. I actually start at 30 deg at the root and end at 60 deg at the tip, but who'se counting.

You should see the center of the blade get cut first, and then the cut area extend from your new leading edge contour to the extreme trailing edge. At this point, I will sand the bottom smooth and blend in the undercamber to the new leading edge upsweep. This gives you a good base for your next step.

Now it is time to thin the blade. I mark 1/2" stations, and on a 10x4 prop, start at about .200 and taper evenly to .060 at the tip. I suppose one should compensate for the increase of chord toward the middle of the blade, but I don't. The thickness must, of course match the bottom surface of the blade, I use a caliper which gives me a good flat reference to the bottom.

OK. Now, draw lines on the top at the 1/3 chord and 1/2 chord position all the way out. Start hogging away at the rear section of the blade to give you a very thin trailing edge (.015 or so) and a flat surface to the 50% chord line.

From here on, use a point-source light, and your eyeballs to shape a nice airfoil everywhere. Add your choice of tips (I like Hoerner {Flite-Streak} tips), sand smooth and balance the prop. I have the Top Flite Magnetic balancer, but tossed out that plastic junk hub. I got the nice machined balance hub from Great planes, and use it in the magnets. Superb!

Finally, I give a couple of coats of Urethane spray varnish, recheck the balance, and then I have a real gem of a prop.

Hey Larry - how about putting that "prop how-to" article into format for Tom to include in Stunt News? It appears there are already several of us who would like to try that prop mod, and I'm sure you would do the stunt world a lot of good to publish your tricks so all can learn from your experience! Maybe put in a couple pictures or drawings showing where you take the material off the prop, etc. Whaddya say? Thanks.

Joe Owen.

I'm thinking a 25FP would be adequate -- that's what I'm planning to try in mine. Depending on the muffler, a 4 ounce tank might be enough for two patterns based on my 25 / Twister experience.

Pat Johnston from Boise had a 25FP in his scratch-built Nobler a year or two ago. Some said it was overpowered. The engine weight issue seems to favor a 25 in my mind -- I've heard the tailweight required for larger engines can be considerable.

I put in a nylon bellcrank, solid leadouts, adjustable line slider, and an improved pushrod. Changed much of the covering too. Longest 'arf' project I've ever had...

Larry,

An interesting discussion of how you modified the Zinger. What you didn't say was why you do that and what were the expected and actual results re the stock prop. Can you fill us in?

This prop mod sounds interesting, some diagrams please

LAST EDITED ON Dec-30-03 AT 01:53 PM (CDT)
 
Larry,

In reviewing your upgrading/customization of the control system, I see where you have once again let me down, failing to take a look at the Associated ball ...

Oh, why bother?

Sigh.

Your ARF Nobler is trying to rip your arm off? Only a 1/2A Freak would think that, only a very serious 1/2A Freak would actually write it down.

Come on up! I'll let you fly my (almost) 70-ounce Impact w/Pond Scum 72. If you still have any courage left, we'll then see if PW can get one of the bombers out of mothballs.

Happy New Year!

>Larry,
>
>In reviewing your upgrading/customization of the control
>system, I see where you have once again let me down, failing
>to take a look at the Associated ball ...
>
>Oh, why bother?
>
>Sigh.
>
>Your ARF Nobler is trying to rip your arm off? Only a 1/2A
>Freak would think that, only a very serious 1/2A Freak would
>actually write it down.
>
>Come on up! I'll let you fly my (almost) 70-ounce Impact
>w/Pond Scum 72. If you still have any courage left, we'll
>then see if PW can get one of the bombers out of mothballs.
>
>Happy New Year!
>
>Dan

An edit, because I ran across the following in another thread:

I finally did look over the Associated ball joints, and decided that I like the Du-Bro unit better. My reason is that the length of the threaded area connecting to the pushrod is longer. The Associated is more rugged, I think. The LHS guy said that Rocket City units are better than either one for what I want, and he will get some in.

Larry Renger
think S.M.A.L.L.

And my response is that, Larry, your standards are too low. Plus you may not have had access to the complete line; your objections are easily dealt with.

Did you take a moment to actually assemble an Associated unit and see the (almost) total lack of stiction in combination with virtually zero slop?

My feelings have been hurt, and you well know that I am a SNAG (Sensitive New Age Guy).

>>Larry,
>>
>>In reviewing your upgrading/customization of the control
>>system, I see where you have once again let me down, failing
>>to take a look at the Associated ball ...
>>
>>Oh, why bother?
>>
>>Sigh.
>>
>>Your ARF Nobler is trying to rip your arm off? Only a 1/2A
>>Freak would think that, only a very serious 1/2A Freak would
>>actually write it down.
>>
>>Come on up! I'll let you fly my (almost) 70-ounce Impact
>>w/Pond Scum 72. If you still have any courage left, we'll
>>then see if PW can get one of the bombers out of mothballs.
>>
>>Happy New Year!
>>
>>Dan
>
>
>An edit, because I ran across the following in another
>thread:
>
>I finally did look over the Associated ball joints, and
>decided that I like the Du-Bro unit better. My reason is
>that the length of the threaded area connecting to the
>pushrod is longer. The Associated is more rugged, I think.
>The LHS guy said that Rocket City units are better than
>either one for what I want, and he will get some in.
>
>Larry Renger
>think S.M.A.L.L.
>
>And my response is that, Larry, your standards are too low.
>Plus you may not have had access to the complete line; your
>objections are easily dealt with.
>
>Did you take a moment to actually assemble an Associated
>unit and see the (almost) total lack of stiction in
>combination with virtually zero slop?
>
>My feelings have been hurt, and you well know that I am a
>SNAG (Sensitive New Age Guy).
>
>Dan
>
>

by any act, error, or omission, I have, intentionally or
unintentionally, displayed any breedist, disciplinist, sexist, racist,
culturalist, nationalist, regionalist, localist, ageist, lookist, ableist,
sizeist, speciesist, intellectualist, socioeconomicist, ethnocentrist,
phallocentrist, heteropatriarchalist, or other violation of the rules of
political correctness, known or unknown, I am not sorry and I encourage you
to get over it.

I'm going to sue the dirt! I almost choked to death on a piece of popcorn laughing at his s.n.a.g. remark.
I think that a a woman first said the phrase ' your so INSENSITIVE ' to describe ' da dirt.
I'm sure that somewhere someone is saying' thats my boy'
Dennis

Dennis,

Larry Cunningham and CatDaddy both spewed in separate but related incidents, you have today choked on popcorn.

I'm getting to be pretty good at this stuff.

And liking it more all the time.

Too bad I don't need any more hobbies.

Happy New Year!

>Dennis,
>
>Larry Cunningham and CatDaddy both spewed in separate but
>related incidents, you have today choked on popcorn.
>
>I'm getting to be pretty good at this stuff.
>
>And liking it more all the time.
>
>Too bad I don't need any more hobbies.
>
>Happy New Year!
>
>Dan

Dan, it was that wonderful stunt codpiece you were wearing! (No one can model stunt gear quite like you..)

[photo not recovered: 3ff2f54d121b1b79.jpg]

As Big Paulie says, "You know why you're still here? Because you make me laugh.."

[photo not recovered: 3e69bb3870f12ad5.jpg]

"What the country needs is dirtier fingernails and cleaner minds." -Will Rogers

>>Dennis,
>>
>>Larry Cunningham and CatDaddy both spewed in separate but
>>related incidents, you have today choked on popcorn.
>>
>>I'm getting to be pretty good at this stuff.
>>
>>And liking it more all the time.
>>
>>Too bad I don't need any more hobbies.
>>
>>Happy New Year!
>>
>>Dan
>
>Dan, it was that wonderful stunt codpiece you were wearing!
>(No one can model stunt gear quite like you..)
>
>[photo not recovered: 3ff2f54d121b1b79.jpg]
>
>As Big Paulie says, "You know why you're still here? Because
>you make me laugh.."
>
>[photo not recovered: 3e69bb3870f12ad5.jpg]
>
>"What the country needs is dirtier fingernails and cleaner
>minds." -Will Rogers

by any act, error, or omission, I have, intentionally or
unintentionally, displayed any breedist, disciplinist, sexist, racist,
culturalist, nationalist, regionalist, localist, ageist, lookist, ableist,
sizeist, speciesist, intellectualist, socioeconomicist, ethnocentrist,
phallocentrist, heteropatriarchalist, or other violation of the rules of
political correctness, known or unknown, I am not sorry and I encourage you
to get over it.

Suprisingly a ride up to Orange county Chopprs isn't that far. Shame I gave up riding them 20 years ago. Dennis

I already flew Proparc's Pondscum 72 monster. He said I looked Nationals level all of a sudden. I hated flying it. The plane flies just fine, but it just ain't my style! Give me an epee anyday over a two handed broadsword! I want to finesse a Formula 1 car, not horse around a monster truck!

Not so, I replied to that request yesterday! Look at the original thread where you suggested I look at them! Gotcha!!!

>Larry,
>
>An interesting discussion of how you modified the Zinger.
>What you didn't say was why you do that and what were the
>expected and actual results re the stock prop. Can you fill
>us in?
>
>Ted

As suggested earlier by Larry, I used one of his reworked Zingers on my OS 25 FP when I was flying a Gyrator. As you can imagine, the prop as describe by Larry, hardly looked like a Zinger other than Zingers use good wood. That Gyrator was about 26 oz and was very happy with that engine and prop in a fast 2-cycle run. The engine never sagged and the airplane never stalled or mushed and had a presentable square turn which is a good measure for a flapless OTS design. It was the best prop that I had used on that airplane. It was good for one 2nd at the Nats and a 3rd at VSC before I destroyed the airplane, engine and prop by hooking the lines up backwards.

Well, Ted, I regard a propellor as a wing. Helical twist, flying in a circle, but a wing all the same. It has a pretty low Reynolds Number if I recall correctly. As such, the airfoil should be appropriate to that Rn. Old FF airfoils have proven themselves over the years, and that is backed up by all that wonderful glider airfoil wind tunnel data generated by Selig, et.al.

A better airfoil is truly "something for nothing", if you don't count the 2 hours + to modify the prop. You get both higher rpm, and a lot more thrust with the same engine. It is what you can do yourself to match the performance of some of those beautiful CF props in sizes where they don't exist.

I figure that it took 10 hours to build the Noblarf, and typically 100+ hours to do a competition model from scratch. So what is a couple of extra hours to make it work better? Besides, my props are REALLY pretty when they are done!

Larry,
As someone else mentioned, could you upload a photo of that reworked prop? As they say. a picture is worth a 1000 words.

Unfortunately, I can't upload a photo this week. I have a problem with my home computer in that it won't upload photos to SSW. I can do it at work next week.