Fuel supply for my TD, questions and answers

**RknRusty** Fri Nov 25, 2011 11:36 pm

As you all know by now I've been experimenting with my newly acquired TD .049 on my Stuntman23. First came the pressure-less bladder, a balloon with the air evacuated and a perforated pickup tube. It ran great on the bench but not so good in the air. It stalls whenever I flip it inverted.

So now I have a backplate ready to be pressure tapped and I want to use the best tank for my stunting and inverted flight. I have a couple of wedge tanks in my shopping cart at Brodak. I wanted a 1.5 ounce, but they don't have one. So I have a 1-1/3 ounce and a 2 ounce wedge in my shopping cart that but I haven't checked out yet.

In the mean time I was at my LHS and bought a 1 ounce Sullivan clunk tank. I had to use a thin tube to make the clunk actually work, and I plan to try it out tomorrow. It will be on only suction as I haven't drilled the pressure tap yet. I'll probably do that next week. It looks a little ridiculous sitting on the wing, but hopefully it will fly okay like that.
I have the TD radial mounted so I'm going to probably have to gouge out the firewall a bit to make room for the pressure tube.

Now my questions:

Should I have any expectations for decent performance with the Sullivan on suction? How about on Pressure?
Is the wedge the best tank to use when I get my pressure line hooked up? Do I hook the pressure line to the bottom vent, and then after the engine is running, cap off the fill tube so pressure builds up?
Is there any need for a check valve in the pressure line to keep fuel from back-flowing into the crankcase?

I've been reading search results for 4 hours and everyfreakinbody is an expert, but I found no definitive answers. I'm sure I will here.
Thanks,
Rusty

dankar04 Sat Nov 26, 2011 12:26 am

I have a 1 1/3oz. Brodak uniflow tank in a profile 1/2A stunter. 250Sq. " wing. Stock TD on suction. Engine ran pretty good but not as good as I expected. Maybe with pressure backplate it might have done better. My imported 1/2a combat ships have TD's .049/.051's with bladder and Texas timer Kirncraft nva's. This is ticket for steady run. I use low pressure but it is pressure bladder tanks. The Sullivan 1 oz. is ok for RC but I think UC to much problems but somw have used them. 1/2A's can be a pain. Some guys use pen bladders or small ballons. Hold them in with 35mm film holder or rocket tube from estes. Stunthanger has extensive 1/2A UC section. To sign on just fill out info as they want to know who is joining. Some guys just join forums to sell and leave no info, that doesn't work on stunthanger.
Dan Airplane

nitroairplane Sat Nov 26, 2011 4:35 am

On my pressure tapped engines I run a 38cc 1/16 scale rc car tank and get better performance than I would on a wedge.

PV Pilot Sat Nov 26, 2011 5:31 am

I've never ran pressure on a tin wedge before, but you will have to cap off one vent or the other it seems.

The check valve is not a requirement. But to error on the side of less frustration on a non exhaust manifold pressure system, I would pull both lines off the motor side and fill by one or the other, preferrably the pickup side. If you fill by the vent side, once the tank gets full it tends to push fuel out the pickup side (or immediately pushes it out).

I usually build my sullivans with 3 tubes/lines. a fill tube, vent tube, pick up tube. For filling I hemostat off the pickup tube line, pull the pressure/vent line free from the motor, and fill using the fill tube right on the tank. To pressure cap the fill tube, I use a carburator vaccum cap pushed over the tube with a piece of tight fitting fuel line pushed over top that. You could do the same little trick to cap off your tin wedge extra vent. I could get into fuel dots, "T" fittings, fuel line pinches and everything, but I will leave that for someone else if they so choose.

You know, I had all this highlighted and about clicked delete, but I'll let it ride, what the heck.

fit90 Sat Nov 26, 2011 8:33 am

Rusty,

PV hit a big nail on the head. You can not reliably fill the tank if your vent line is still connected to the pressure line unless you want to risk flooding the crank case. If you go with the radial mount I would incorporate a check valve in the pressure line and include a third line for refueling. This way you do not have to clamp off the pressure line when refueling. Later today I will try to post a pic of a two line system I have on a plane. It is butt ugly but simple as can be.

Bob

fit90 Sat Nov 26, 2011 9:11 am

Fuel supply for my TD, questions and answers Dscn0342

[img]https://i.servimg.com/u/f48/[url=https://servimg.com/view/16987235/42] Fuel supply for my TD, questions and answers Dscn0344

16/98/72/35/dscn0343.jpg[/img][/url]

Heere are a few pics (I hope) of a two line pressure system with a reedie and a check valve. I will get those pics of the tee dee system soon.

Bob

fit90 Sat Nov 26, 2011 9:12 am

Fuel supply for my TD, questions and answers Dscn0345

Here'as the third pic

fit90 Sat Nov 26, 2011 12:40 pm

Fuel supply for my TD, questions and answers Dscn0419

[img]https://i.servimg.com/u/f48/16/98[url=https://servimg.com/view/16987235/48] Fuel supply for my TD, questions and answers Dscn0421

/72/35/dscn0420.jpg[/img][/url] Fuel supply for my TD, questions and answers Dscn0422

Here are some pics of a simple two line pressure set up

fit90 Sat Nov 26, 2011 12:46 pm

Fuel supply for my TD, questions and answers Dscn0423

[img]https://i.servimg.com/u/f48/16/98/72/35/dsc[url=https://servimg.com/view/16987235/52] Fuel supply for my TD, questions and answers Dscn0425

n0424.jpg[/img][/url]

Here are some pics of a three line pressure system. The line from the tank to the venturi has a clunk in the tank. The line from the pressure tap to the tank has a clunk on this set up. It can also go to a vent line. The line that is clamped closed with the hemostats goes to the vent tube in the tank. The line going to the venturi is the only one that needs to be on a clunk or your chosen in tank fuel pick up device. One of the two remaining lines needs to be set up as a tank overflow for filling. Yhis is typically also the vent tube in two line setups. The third can either be a vent type or clunked depending on your theiries on tank set up.

Hope this helps,

Bob

gcb Sat Nov 26, 2011 12:48 pm

RknRusty wrote:As you all know by now I've been experimenting with my newly acquired TD .049 on my Stuntman23. First came the pressure-less bladder, a balloon with the air evacuated and a perforated pickup tube. It ran great on the bench but not so good in the air. It stalls whenever I flip it inverted.

Did you make sure the baloon was in line with the sprinkler in the venturi?

I've been reading search results for 4 hours and everyfreakinbody is an expert, but I found no definitive answers...Rusty

All ANYONE can do is offer their experiences...YOU still have to make it work. Good Luck.

George

**RknRusty** Sat Nov 26, 2011 8:18 pm

Good reading, thanks guys. I'm in the middle of the Carolina-Clemson game, My home team and an intense rivalry dating back over 100 years. I'll get back to this after I recover from football. ESPN, in case you're interested. It's halftime as I write this.

Mark Boesen Sat Nov 26, 2011 8:34 pm

It looks like a good game, I'll take the "Old Ball Coach's" team for the win!

p.s. why don't you just go with a balloon (pressurized) tank? read Dankar's post.

Big Al Sat Nov 26, 2011 10:03 pm

RknRusty wrote:Good reading, thanks guys. I'm in the middle of the Carolina-Clemson game, My home team and an intense rivalry dating back over 100 years. I'll get back to this after I recover from football. ESPN, in case you're interested. It's halftime as I write this.

I trust your home team is Carolina 34-13!
al

**RknRusty** Sat Nov 26, 2011 10:22 pm

Nobody thought the evil genius could adapt after the SEC learned to defend against the type of game he devised at Florida. Steve Spurrier is ours now and he has a whole new game! We're 10-2 with a ridiculous loss to Auburn in September that cost us the East championship. But we beat every team in the East. And beat Clemson(ACC div. champs) for the third year in a row. We should get a good bowl game. Hopefully we can win that for a change.
We were awesome! What a defense! What an offense! What a defense!

I believe you Huskers met the tiggers once back in the '80s.

Oh yeah, bladder... I'll look in to that tomorrow. And all the other helpful posts too.

The Ol' Ball Coach says
Fuel supply for my TD, questions and answers Tigerassback2

Fuel supply for my TD, questions and answers Tigerassback2

[b]

Mark Boesen Sat Nov 26, 2011 11:04 pm

Yep, I remember Clemson had a great team back then, ranked #1, they got 'lucky' (lol) and beat Nebraska, a lower ranked team, Huskers got'em back in '09. Huskers had a two game series with S. Carolina in mid eighties.

I always admired Spurrier and his play calling, even his visor!

Fuel supply for my TD, questions and answers Vacati10

Fuel supply for my TD, questions and answers Vacati10

**RknRusty** Sat Nov 26, 2011 11:15 pm

Okay I'm listening to the after game call in show and thinking about flying tomorrow. Definitely going to try the new wedgie on my Jumpin' Bean, got my Li'l Satan running right, and If I can get a bladder put together for the Stuntman, it'll fly first.
I know some of the basics of pressurized bladders, I have all sorts of balloons, including the long animal twisty ones, And several potential containers including film cannisters, an aluminum cigar tube and a 1.5 ounce tube from a turkey baster.

Can someone give me a quick tutorial on cranking a TD with a pressurized bladder.
I'll start with what I know:
Put the balloon in a container that will contain the balloon and allow it to expand.
Evacuate the air and carefully fill it with as much fuel as I can and clamp it.
Connect the line to the nipple on my fine thread NVA.
Open the needle... how far?
Crank and try to un-clamp the line while it's still running on the prime? Sounds like a real swift trick.
Watch fuel spew out of the venturi when the last step fails?
How am I doing so far?

Also the stunthangar forum is not accepting registrations right now.

**RknRusty** Sat Nov 26, 2011 11:17 pm

Mark Boesen wrote:Yep, I remember Clemson had a great team back then, ranked #1, they got 'lucky' (lol) and beat Nebraska, a lower ranked team, Huskers got'em back in '09. Huskers had a two game series with S. Carolina in mid eighties.

I always admired Spurrier and his play calling, even his visor!

Yep, Darth Visor, some call him.

**RknRusty** Sat Nov 26, 2011 11:21 pm

Should I use the perforated pickup tube that I was using in my unpressurized bladder so it reaches into the balloon?

Good night.

Mark Boesen Sun Nov 27, 2011 12:11 am

There's several ways to do it, I like the curved tip syringe, the point is small enough to fit into Cox fuel tank vent tubes, no fuel fill tubing needed. Use it to suck out air, clip off fuel line with hemostats or whatever, fill with fuel, clip off, prime, start, remove fuel clip but keep handy incase. It sounds hard but it really is easy and you'll think why didn't I do this years ago.
I can't say how many turns, as every set up is different, maybe start with .5 to .75 turns in from where you're at now.

Fuel supply for my TD, questions and answers Is10

Fuel supply for my TD, questions and answers Is10

Kim Sun Nov 27, 2011 9:06 am

Hey Rusty,

I built this "Big Otto +10%" 10 years ago. I wanted to exercise my Tee Dee's and figured that the original Big Otto's 24" span might turn me into the ground with a healthy .051 up front. So, I copied the plans at + 10%, and built this one that came out with a 26 inch span, and a lot more room to install stuff.

I just used an old Perfect wedge tank (don't remember the size) that was in the box, and the .051 seems to run out all the fuel no matter where the plane is pointed. I'll try to time the next flight to see exactly how long it runs, but I'm usually ready for the thing to quit when it finally decides to croak. The only incidence it's had was a fire-on-starting ("What's that crackling sound?"), but has otherwise been one of my favorite planes.

I do always plug one of the filler holes to keep all the fuel in the aircraft, but that's about it.

I wasn't sure if you were going for light-speed performance, or just a full run, but thought I'd toss this in.

Fuel supply for my TD, questions and answers 1_36

Fuel supply for my TD, questions and answers 1_36

**Cribbs74** Sun Nov 27, 2011 10:28 am

RknRusty wrote:Okay I'm listening to the after game call in show and thinking about flying tomorrow. Definitely going to try the new wedgie on my Jumpin' Bean, got my Li'l Satan running right, and If I can get a bladder put together for the Stuntman, it'll fly first.
I know some of the basics of pressurized bladders, I have all sorts of balloons, including the long animal twisty ones, And several potential containers including film cannisters, an aluminum cigar tube and a 1.5 ounce tube from a turkey baster.

Can someone give me a quick tutorial on cranking a TD with a pressurized bladder.
I'll start with what I know:
Put the balloon in a container that will contain the balloon and allow it to expand.
Evacuate the air and carefully fill it with as much fuel as I can and clamp it.
Connect the line to the nipple on my fine thread NVA.
Open the needle... how far?

Rusty,

Here is how I start my TD with a pressure fitting. Basically the fuel will push itself to the carb with pressure with either tank above carb or with a balloon I suppose. What I do is close the needle valve, prime through the venturi. I flip the prop till it kicks over. Then I slowly open the needle valve till it fires again. Keep opening the needle valve slowly until it runs. This is reverse from the usual way, but it keeps the engine from flooding. The thing you have to remember is it will start lean and you have to open the needle valve until you achieve correct RPM as opposed to closing it to lean it out. if you do it this way you will never flood the engine.
Crank and try to un-clamp the line while it's still running on the prime? Sounds like a real swift trick.
Watch fuel spew out of the venturi when the last step fails?
How am I doing so far?

Also the stunthangar forum is not accepting registrations right now.

**RknRusty** Sun Nov 27, 2011 11:54 am

cribbs74 wrote:Rusty,

Here is how I start my TD with a pressure fitting. Basically the fuel will push itself to the carb with pressure with either tank above carb or with a balloon I suppose. What I do is close the needle valve, prime through the venturi. I flip the prop till it kicks over. Then I slowly open the needle valve till it fires again. Keep opening the needle valve slowly until it runs. This is reverse from the usual way, but it keeps the engine from flooding. The thing you have to remember is it will start lean and you have to open the needle valve until you achieve correct RPM as opposed to closing it to lean it out. if you do it this way you will never flood the engine.

Thanks Cribbs, that makes good sense. Speaking of priming through the venturi, I found that to be the easiest way to start my Medallion the other day. Maybe because it's harder to prime through the slit exhaust ports I put on it with a short piston.

**RknRusty** Sun Nov 27, 2011 2:12 pm

That was TOO easy! Very Happy

I wiped the memory on my camera and I'm off to fly. See ya later. Biplane

**Cribbs74** Sun Nov 27, 2011 5:04 pm

RknRusty wrote:That was TOO easy!
I wiped the memory on my camera and I'm off to fly. See ya later.

Rusty,

Did it work better using the method I described?

fit90 Sun Nov 27, 2011 5:25 pm

We're all still waiting for at least a report on how things went. Pics or a video would be better.

Bob

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