Jumping into a Bean

Coming along nicely Fred ; never owned a bean but heard there good little planes Looks like beam mount only , the Medallion should take it for a ride ! Eric

The engine I prefer is a new short nosed Norvel .049 bone stock and danged near exact size to the plan Brodak .049

Fuel tank done (except a leak test).... fairly straight forward.... vent on top, pick up ends at the center in the dished out part of the cigar tube top and centrifugal force should keep the pipe submerged until enpty






Ken Cook actually inspired me to plug round tubes with balsa disk and epoxy to seal/fuel proof the assy.... I had two different diameter cigar tube tops to consider and choose the larger accepting the slight hump in the airfoil above and below the LE

I think this tank will work and I don't really care about any particular total flight time

BTW I added 1/2" TE to the back of the wing for ever so slight larger Sq inches and just to be a kit basher in a smallish way

Would not be hard to make uni flow with a third copper tube just shy of the length of the pickup tube....but more complicated fitting of the center sheeting

This cigar tube tank and center pickup, once epoxied to the LE, will be centered on the venturi so should do ok upright or inverted...we will see....once finished there is no practical way to raise or lower it

Fred, a very important factor of a tank is it's relationship to the engine. The tank you picture is waaaaaay outboard of the centerline of engine. If this was a bladder, this is a non issue. The short nose AME/ Zeus / Aero engines have a huge venturi. When you combine this with your tank setup, you seriously compromise the fuel draw. These engine work with muffler pressure but on suction, I would be very surprised to see if you will get even a few laps. The tank needs to be for best results directly behind the engine. Unfortunately, this won't happen on a profile. So the idea is to make a longer narrow tank which keeps the pickup closer to the engine and making it as close as possible to the engine. Even mounted profile, I space the engine off of the outboard side 3/32-1/8 using aluminum shims to place the centerline of venturi more inline with the tank. Uniflow will not improve fuel draw. It only recognizes the differences in head pressure as the tank reduces and keeps the engine run consistent. Centrifugal force is working hard against you here equally which can cause the engine to even quit on launch. But, one never knows in control line, it could run flawlessly.

Ken you have jumped ahead, grin.

I learned a lot from all your different posts on this subject and had considered the outboard distance as well as the vertical alignment

I am sort of hoping a piece of fuel tube in the air stream will give some ram air effect...but doubting that, may well use the muffler and pressure tap

I has also considered using JB weld to form a choked down venturi opening for better suction feed....thinking along the lines of you shaping a spent prop into a venturi adapter for the TeeDee NVA and venturi

Hell Ken I am even thinking about an experiment with a balloon inside the next outer rib bay (sheeted) as a air pressure source to the vent as a sort of pressurized system...knowing full well it will not be a real constant pressure.

Hi Fred. I like that cigar-tube tank. Do you have another tube to try? I was thinking.. why not redesign it (same size..) and just move it to the first "inboard" rib-bay.. (same orientation) only drill "through" the center of the spherical section and install the pick-up there.. and a vent at the opposite side; turned-up and forward through a slot in the top-sheeting.

A pick-up could consist of a 1/8" copper lead-out tube installed from the inside-out. The flare prevents it from pulling-out. Seal the "outside" with an epoxy fillet.. or if the tube is tin.. sand the paint off in that area and solder it.

This places your pick-up much closer to the engine and centerline.

I wish I'd started reading this when you first got on it so I could add my ideas for the fuel tank. But you have enough input to work with, so I'll just watch for now .

I was all set to mention your extended TE on the wing, a great idea I think, and I added a full tapered 3/4" on my RF Bean. The Norvel is a good choice. Ken is right, of course, uphill fuel draw is going to be a big problem, especially with no venturi as it appears. I'll look and see if I have one to send you, but I like the shaped and tapped prop hub idea with the TD venturi, which seems like an excellent setup. I think muffler pressure is always a good idea. Could you rotate the tank 90 deg(front to back) and live with an even worse hump? If I didn't run a bladder, that's the way I would orient the tank... but you already know which fuel system I would choose... especially with a Norvel. In any case, this will be a badass Bean.
Rusty

Roddie... unfortunately the BC and lead-outs will only allow next outboard rib bay location. Orientating it cord wise still has the fuel pickup a long ways from the NVA and pickup tube end would need to be moved forward out of the deep dimple and angled for the outside

This tube top is 63/64ths and the next smaller is 7/8ths diameter.  Had thought of using the smaller and doing like ken did with the Big Otto....



But the area just aft of the engine crutch and the LE would be severely compromised requiring even more weight of added thin ply tripplers and this also puts the fuel tank empty or full weight forward of the CG

I just checked and the short snout .049 does NOT have the exhaust lip to hold the dinky muffler. I have a .061 big mig it fits

I could just use the Big Mig but it is a full Oz heavier than the .049 shorty

I think I will just do the Ken Cook mod and add a TeeDee NVA and venturi ... mock up a test stand with the proposed fuel tank hanging below the same distances as on the model, and see if the modified engine will draw fuel up against gravity...  I know in flying trim the Centrifugal force will be greater than gravity

I may just cut back the next rib outboard, make two more ribs, put in a "two rib bay" length of cigar tube as bladder compartment

decision decisions

Thanks all for the input

If you don't need pressure just sheet in a rib bay with a wall about halfway back and use a party balloon. The shape of the space is rather unimportant really.

The .061 is way too much engine.

Phil

I see your dilemma Fred. One more idea if I may.. except; tank-size definitely limits this approach. Whilst the fuse is still separate.. you could cut a pocket (hole) for a short wedge-tank through both doublers.. enough for the wedge to fit through from the inboard-side with it's feed-tube outboard.. and the vents inboard. I know it sounds un-nerving to cut through both doublers.. but it only has to be enough for the feed-tube to clear the fuse (with fuel-line installed). Think of it as a "pocket" rather than a hole. Start small and use a file/rasp to form the angle of the wedge to seat squarely. Pad the wedge where it passes-through the fuse for anti-vibration as well as adjusting the tank's offset-depth.. and you'll achieve the feed being on-center with the venturi. Use the tried and true rubber-bands hooked over pins top/bottom inboard, to hold in place.

This largely depends on the area (height and length) that you have between the wing's L/E and the engine.

Looking at your fuse.. I think this type tank would work.. but you wouldn't have as much flight-time as with your cigar-tube.



I know that 1/6oz. is not a lot of fuel.. but maybe a larger short wedge would fit?

Roddie I am always cogent of your time expended to help a fellow modeler...... mucho thanks

In this case I will never ever again use the dinky perfect tanks...they ALL require opening and fixing and my arthritic fingers can not do the dinky work anymore

I have decided to forge ahead with my cigar tank (too much fab time to abandon it) but an experiment with bladder air pressure to the vent of the hard tank ....I can place a "no fuel use" bladder in the next bay outboard and fill it until I see the covering bulge...attach to the full hard tank vent and have fuel pressure system .... I am actually pretty confident this will work as I already mocked it up on the test stand and I don't have to fuss with gravity/ centrifugal force and other flight issues

OTHER thoughts

Rustie's bean bash...I like twin booms

This plane begs to be a longer WS and cord

Kit bashing is one thing but fortunately Sig sells the correct LE and TE stock so I will scale the wing to a more acceptable size for the Big Mig .061 waiting for a ride

I am going to finish the Brodak Bean but start a Fred scaled scratch version tomorrow 1 inch linger fuselage, 4 inch wider wing and twin boom tail with the Big Mig .061/muffler/cigar tank set up

PS
Cutting ribs now using the Brodak fuselage cut out plug....before I get called in for dinner

Well.. that's cool Fred. I'll be curious to see how that works. I like the idea. Remember my "regulator for bladder" thread? That met with some controversy... I wonder though; if you could apply that principle to the air-feed.. to have it be more like a muffler-pressure affect on the cigar-tube? Basically it would be fitting your air-bladder with a tube having a tiny opening.. instead of a full-size tube. You only need enough pressure to assist suction.. correct? Don't forget to clamp the line when pressurizing!

All good thought sir

Been using pressure for a long time now and some are very high and some just low depending on the bladder tube materiel

I was thinking red cap but they all try to bulge too fat for the Bean wing

now thinking a snake of thin walled Texas Timers stuff inside next outer rib bay with some what more volume of air than the hard tank itself.........

I have not really measured the total hard tank volume but it looks like about a 3rd of a 2oz syringe...so I fill the tank with .75~ 1.3 oz fuel and the air bladder with 1.5+/- oz air...no leaks... should stay above atmospheric for full fuel load

A little off-topic.. but I know how much you like flying-wings. While brainstorming your predicament earlier today.. I thought about your cigar-tube.. and how I asked if it would fit chord-wise inside the nearest inboard rib-bay, up against the leading-edge.. for the suction-feed that you wanted. I didn't post this pic.. because it still wouldn't have worked with your Bean.. but might be an alternative for a different "short-nosed" model.




That floral tube has a .600" diameter. I used a sm. flared lead-out tube for the feed-fitting. A #43 drill (.089") to drill the hole.. X-acto knife to deburr the hole and also install the fitting inside the tube. Ball-point pen to hold the fitting in-place while installing the fuel-line. It holds 10cc's (not including a stopper)

Fred,

They move pretty quick with a TD so the .061 is going to scoot. You could probably adjust line length a bit to compensate. 42' is probably your starting point.

Here is a video of me flying a bean from a couple years ago. It has a 3/4 perfect tank and a TD .049 35' lines

fredvon4 wrote:...Rustie's bean bash...I like twin booms

This plane begs to be a longer WS and cord

Kit bashing is one thing but fortunately Sig sells the correct LE and TE stock so I will scale the wing to a more acceptable size for the Big Mig .061 waiting for a ride

I am going to finish the Brodak Bean but start a Fred scaled scratch version tomorrow 1 inch linger fuselage, 4 inch wider wing and twin boom tail with the Big Mig .061/muffler/cigar tank set up

I used the Big Mig .061 on the Refried Bean. If you want the measurements, let me know. It needed zero balancing when maidened.
Rusty

Roddie

Exactly as I had envisioned what your were describing... I looked at one of the smaller diameter Cigar tubes and though the same idea...Eyelet JB welded back at the dimple and let Centrifugal force be the feed

The problem as have read about early tank designed is the fuel has weight and as depleted the effective pressure slowly diminishes

I suppose for a sedate reed engine the slowly getting leaner and leaner would not be a problem because they have a set by the reed RPM limitation built in and high castor would prevent cooking the engine

Of course that is all theoretical and begs to try an experiment with and really see if it is a big or just annoying problem

Update because I can feel Ken, Rusty, Kim, and Ron all rolling their eyes and wondering why screw with a tank that probably will not work and Just use a freaking bladder

Final decision... under slung Bladder via Rusty's different exposed bladder set ups

Made a set of parts for slightly larger .061 Big Mig powered Bean for a future project...rip off of Rusty's twin boom bash....grin

Too humid and PITA weather right now to get serious on final covering and paint of the J Bean

I even have toyed with the idea of two Bean wings in a Manx Cat combat.....biplane type configuration.....nah this dinky wing is a royal pain to build for my aging hands

some progress

I saw a different method of sewen hinges without holes that I did for first time and works well

but next time I will start the thread glued down on the trailing edge instead of LE...you can't see the nubs in this photo, plus I will oay better attention to being straight....grin....we learn from mistakes



On Stunt hanger Mike Griffin showed his wing holding method to do iron on coverings. So I made a quick one with a bit of 12x 16 inch cast off cedar board and foam .....worked well and the 1" thick board has enough weight to do larger wings

fredvon4 wrote:Update because I can feel Ken, Rusty, Kim, and Ron all rolling their eyes and wondering why screw with a tank that probably will not work and Just use a freaking bladder

Final decision... under slung Bladder via Rusty's different exposed bladder set ups...

What, me roll eyes?! Yay, good choice. Get a 1 way fill valve to stick in its tail and train it so the front fills first.
http://www.ebay.com/itm/NEW-Fourmost-Auto-Plug-One-Way-Valve-138-NIB-/291312932776
Once you go bladder, you'll never go back!

Note: center of bladder tube straddles CG.