combatpigg

My Feedback: (3)

mrfx2001, I just went there[to LARRYs' site] with a GOOGLE search and I found the tubing listed under accessories. I can get it at fishing tackle supply stores, 1/8" thin wall is a good size to try. All it takes is 3 inches worth to make a bladder. Tie a good hard knot in one end, cut to length, and then build it like I said before. A product engine or any reed valve engine can give a decent setting, but pretty critical. If you want success running a bladder with a TD, you will need an aftermarket needle valve with a very fine thread. The AME .061 NVA is barely adequate. If you want to see real precise metering, then needle a FORA or CYCLON sometime! For larger engines the OS .10 NVA or NELSON remote needle is the way to go.

Unless you are trying to avoid high G force lean outs [or flame outs], or you are running an over sized venturi that doesn't draw fuel well on suction, THERE IS NO PERFORMANCE ADVANTAGE to running bladder pressure, and it is more trouble than just running a hard tank.

Big Al-RCU

Hi CP, I have never run a bladder tank and have a question or two. I assume the latex tube you describe is a pressure feed (not just a positive expulsion bladder) and that it is obviously filled under pressure. I seem to remember seeing the CL guys using a clamp (hemostat?) to close off the fill line with the pen bladder tanks of the time while they reattached the fill line to the carb.
My question is in the starting sequence. How do you keep the engine from flooding? Is it critical to time the priming/starting with removing the clamp? Or is it a real trick? These unknowns have keep me from trying the pressure tank, even tho I know that they have been used with success for many year's. I'm sure it isn't as big of a problem as I'm making it out to be.
Thanks, Al

SGC

Al,
Theres a good description of running a bladder tank here :- https://ssl10.mysecureserver.com/kit...dex_store.html
Stewart

Big Al-RCU

Thanks Stewart, that is indeed an excellant description.
Al

DICKEYBIRD

Hey Al, I've run bladders before and the starting process is fairly easy but you oughta see Larry D. do it. Guys like him and C/P have been running bladders so long, they make it look unbelievably easy! He also uses a home-made (I think) clothespin-like clamp made of wood to clamp off the line that doesn't damage it.

mrfx2001

My Feedback: (2)

MR COMBATPIGG,
I can't disagree with you more.
In the 60's when I flew WINDERS & Fox 36X combos at 70 mph plus (U_control combat) with baby pacifier bladders, the ease of starting and consistency of run was the best part of bladder systems. If done correctly there should be an increase in RPM over a conventional system. We would build beer cans into the wing to hold the unit and it saved the wing innards when they exploded. (The Bladder) I cannot find the old stuff I used years ago to reenact the crime. So I thought I'd try some current day hardware. You are correct about the needle even without a bladder. That was the first thing to get nixed. I'll turn off all the network fire control and try again on the web site.

combatpigg

My Feedback: (3)

Show me ONE SINGLE AMA C/L SPEED RECORD that is held by a bladder fed engine. For that matter, show me where ANY bladder fed plane holds ANY records in RC PYLON,[and some F1 pilots did try bladders], or over in EUROPE at the RC SPEED CUP. I'll save you the trouble of looking it up, because there are none. Like I stated before, inless you are playing with an oversized venturi that can't draw fuel well enough on its' own to run off suction, there is no RPM advantage. Any engine that comes ready to run off of suction will be able to draw as much fuel as it needs through suction to reach max rpm. Unless you do something to mechanically alter the engines' ability to use fuel at a faster rate than suction can provide, all you have done is give the engine more fuel than it can use, and made the system more critical to adjust. The 36X, with out the suction insert would definately show a gain with a bladder, it wouldn't run very long otherwise with that big gaping square hole up front. With the insert in place, and there is NO DIFFERENCE. I ran VOODOOS both ways with this engine, and all the bladder did was give better runs through the manuevers.

I maintain that it is a misconception [and a wives' tale] that the pressure system on its' own will increase rpm and the records pretty much back that up. Put a bladder on a 18,000 rpm BLACK WIDOW, and you will still have a 18,000 rpm BLACK WIDOW, unless you open up the intake. Same goes with any other engine that is set up to run off a hard tank.

HI AL! Sounds like you got pretty well lined out on how to do this stuff with LARRYs' article. The SULLIVAN small tubing works real well to connect to the engine, because it is easy to pinch off with your finger tips, instead of handling the surgical clamps. I guess to sum it up that I think using bladders is a neccessary evil, if it isn't needed, then there are enough draw backs to just go with the trusty tank. I think it is a GOOD way to set up a pusher design, this way it don't go rich and lose power when you want to climb, and good for any .049 with a venturi big enough to get your little finger into.

mrfx2001

My Feedback: (2)

Well, I’m no contest flier. I’ve been flying for over 30yrs as a sport flier and I am not about to compare notes on contest equipment and records or any of that other stuff I just don’t care about. I can comment on things I have tried and have worked well for me and it should be received with that thought in mind. I’m just trying my hand at 1/2A bladder. By the way, after tuning down the four firewalls that protect the in-house net, the site you referenced came through fine.
Fred

combatpigg

My Feedback: (3)

HI FRED, the pressure feed controversy goes back at least as far as the MODEL A FORD days. Those engines were gravity fed, and if you hopped those engines up with every trick in the book, then it was neccesary to pump up the fuel tank to meet the increased demand that gravity couldn't supply. The driver [in the get away car] had a bicycle type air pump that was strapped to the steering column that he had to manually actuate, so those dual ZENITH UPDRAFT carbs wouldn't run dry.

If you reach the point with a model plane engine where you have opened the high speed needle up to the point where it falls out of the spray bar, and you are STILL too lean, then it is time to consider a bladder feed. Otherwise, the bladder systems' main function is to G FORCE PROOF your fuel delivery, and to a certain extent help deal with OVER CARBURATION [too big of an air hole]. With those scenarios, and without pressure feed, the engine just wont stay lit anyway.

wjones

looking for combat wing plans. Are the 1/2A combat wing home made.

thx, wil

wjones

combatpigg the 1/2A wings you have pic of, did make them up your self? how do they fly?

thx, wil

combatpigg

My Feedback: (3)

They fly real well. The tip fins give enough yaw control, even with the other guys' streamer hanging off a wing tip. The lifting airfoil allows tight manuevering without losing much altitude. The open frame work is easy to repair with clear tape and CA glue at the field. The frame work is a little bit light, so you have to pay attention to warps if you are bringing the planes out from storage. You have to look them over and iron out any twists. The action is real good if you are using sport type engines and 6x3 props. I have cranked up the intensity by using hot TDs and AMEs, but the wreckage goes way up and the quality of the combat goes way down. At this point all you are doing is high speed jousting. The best engines are BIG MIGS and AP HORNETS, they can haul around the 36" span , 14 oz planes at a manageable speed with lots of good action. Hope you give it a try!

wjones

Thx, combatpigg for the info! is that your design

wil

combatpigg

My Feedback: (3)

Yeah........if you can call it that.....a rectangle with an engine hanging off of it.

combatpigg

My Feedback: (3)

Sounds like some interest in 1/2A RC combat has stirred up at RCCA. The word is getting out, and maybe some guys are getting tired of spending $100 bucks everytime they go out to play? It's not hard to have a $100 round if things don't go right, you could have a $400 round as a worse case. Very rare in 1/2A to see much more than a stripped servo. Anyway some questions have come up about foamie construction. I don't have an RC foamie to show, just some C/L jobs, but the principle is the same. The center motor block and stick is the back bone that anchors the whole works. Aluminum mounts are made to go with the engine so that you can simply bolt them to the motor block that is built into the wing, or just use 1/4x3/8 maple beams. This wing has a 3/8x1/8 spruce spar top and bottom, laid into a recessed groove that can be done with a dremel router, or on the table saw. My favorite layout is the flying wing, with winglets and just elevons for control. If you extend the carbon tube spine out, then you could go with a conventional aileron / elevator plane, with enough room forward of the wings' L.E. to strap a 2 oz tank on. Here are a couple of photos for example..... it's easy to form the recesses in the wing panels, to recieve the center piece, I use a dowel with sand paper glued to it, and either an EXACTO or razor saw to cut the notches for the motor block. I think those ACE wings would make great foundations to something build from, and just cover it with 2" wide clear tape [the thin stuff].

scudrunner77

Fill me in CP.... What's RCCA? Radio Control Combat Association?

Thanks for covering up this time[8D]

combatpigg

My Feedback: (3)

That's them. The RCCA has a yearly membership fee and they keep the flyers in touch with what is happening and where. There isn't much going on in this immediate area except for C/L combat. Their forum looks very active, which explains why the RCU combat forum is usually fairly dormant. My FSOD thread from last summer is still on page one, I'll bet .

BMatthews

Hey! What about some fun time Sure Start Simple Combat (SSSC) at the Mission Wings Small Fly this year? I'd be up for a go at that! Simple flying wings with a streamer.

36 inch span and a 9 inch chord with tip or center fin. Two channel radio and a couple of cheap midi sized servos.

Bipe, CP? Wha'chya say?

ptulmer

My Feedback: (5)

Bruce, why not use Ace foam wings? Apparently Ehobbies will sell them to you guys,(international) but not me.[:'(]

If you guys know of another source for them, it seems like a nice prefab'd alternative.

BMatthews

First of I sort of hate foam. Secondly the Ace wings are probably too narrow to really do well and finally I can likely build lighter and stronger than the Ace wings would let me.... but mostly I hate foam...

With one exception perhaps. Years ago I cut some cored for CL combats and covered them with a thinned mix of white glue and newsprint. The newsprint was multi layered in tapering sizes around the engine and along the high point to form local reinforcing and spars. This worked great and I went gopher hunting with it a few times with no perceptable damage. Only a mid air where the opponents prop met the wing finally caused something worth repairing. Yet despite this toughness it came out surprisingly light.

These days I think newsprint and water based varnish would work super.

ptulmer

My Feedback: (5)

Bruce, ehobbies finally returned my email. Apparently they moved the warehouse and are still updating the website...? Anyway, it seems that one day... eventually... if I'm good... they might just decide to sell me some more Ace wings.

The new product by Thunder Tiger is far lighter than the originals. Like 1/2. I'm no fan of foam myself, but it does have it's uses. Why not ripstop nylon and waterbased poly? Like the big OPEN B boys use. I've got one tapered and one CC set left. Gotta do something about this tonight!

Steelie

My Feedback: (18)

To anyone,
I am kinda stuck with a recent on-line purchase. It is of a Progressive Miniature Aviation Zero combat plane kit. I need the plans as it came with Morfis plans and cannot be built with them. I need the Progressive Zero plans. Any help would be appreciated.


Steelie

combatpigg

My Feedback: (3)

BRUCE, the only issue, according to ANDREW is the landlords don't want their cows eating streamers. On a calm day, it is easy to retrieve the fallen crepe paper, but on a windy day, it's hard to be scrupulous about picking it all up. If they were my cows, I would say,"LET THEM EAT CREPE PAPER". I think the open frame work, balsa wings take about the same time to build as a foamy from scratch, but the foamies are cheaper and if you get into mass production the time per plane starts looking better than the balsa counter parts. LARRYS' LITEHAWKS are prime examples of how light a 1/2A combat plane can be, and if you bring 5 minute epoxy and some scrap spruce, field repairs shouldn't be too bad.