Clunkity clunk

My thoughts so far as well Ken.
Not least of which having to put
Semi loop in the pick up tube to ensure clunk
Is facing rear of tank..
Let's see what/if happens as the rest of you
guys get out of bed...

Why not simple use a Dragonfly tank?
I don't think you can use a clunk in a regular Bee tank, there is simply not enough room for the clunk to move.

Another option is a ballon tank, there is no air in those (when filled correctly) so they don't care about orientation.

The regular BW tank is not only small but the vent tubes are another obstacle that prevent side-to-side motion. Maybe if you get a Kavan extender there will be more room to work with. You could shorten it if you think it's too long. So far Kris has the best idea with the Dragonfly tank, if you don't want an external supply. If, by aerobatic, you mean 3D, and you're going to prop hang, I'm not sure you'll get any clunk to reliably fall between the backplate and the front and not get stuck along the way.

Funny, I was thinking the same thing yesterday. I don't think it would be succesful. I was also thinking of a rigid multi- line pickup tube. I think that would be more doable, but not sure what would happen if a line gets exposed to air.

I think it's just time for an external tank, shame really as I like the look of the bees and they do run well long as there is enough fuel in the tank.

I would set up widow with large non stunt tank and vented metal back plate with both vent tubes having 1 inch extensions turned 90 degrees forward into air stream so when hanging on the prop fuel would not flow out

Texas timers and others sell a very limp and small fuel tube that would not require a heavy clunk to follow around in the tank. Especially if you used one of your extensions we are all waiting for....wink

If you did this with the big tank AND your Large extension...I would extend the Metal Back plate nipple 3/4" or so into the new very deep tank so the clunk on the very small fuel line could swing fore and aft with out kinking. The small fuel line I am describing is probably too small inner diameter to sneak in a spring

Hmm, that might actually work Fred.

Ken Cook wrote: ....... I just feel that you would run into space restraints. This wouldn't allow the clunk to be heavy enough for the tubing to adequately move freely. .... Ken

For clunks to be successful, you'll need to meet 3 requirements:
1) The clunk must have enough mass to follow the plane orientation, even if it does not involve high-G flying.
2) The fuel line must be flexible enough to allow movement.
3) There must be enough room for movement.

With the confined space, even without the filler tubes and venturi tube, I don't think you can find tubing that is sufficiently flexible to support a clunk and follow tank orientation without kinking. I've used the silicon insulation from noodle wire to plumb file canister tanks, but the volume is significantly greater than a Bee tank and the tubing does not need to fold back on itself.

Texas Timers has small diameter tubing, but while it might be flexible enough to use in a confined environment, it likely won't have strong enough walls to keep from collapsing. The tubing is actually "pinch-off" tubing and is used to allow the timers to shut off fuel flow by mashing it flat.

Hmm maybe a revisit to drawing board needed..
These are the criteria,-
The travelling prop is en route and I'm lacking a mount.
I had a kit for an 020 which I scaled up to accommodate
An 049 so the prop has a seat.
The model is typical Johnnie ie Big engine/small plane
So integral tank a bonus, as is twin vent so It will stunt/3d.
I may either look at Bee with extended tank/no vents
Not much power/I had hoped for at least 100 watts per pound
(see my previous power to weight ramblings) or bite external
Tank bullet and go Killer Bee'stard.
Imagine a stunt wing with a carbon boom and tail.Then you'll
see why space is a premium/ I've got to hide 5 servos somewhere
Too.
At least prop not here yet....!

Surfer_kris wrote:Why not simple use a Dragonfly tank?
I don't think you can use a clunk in a regular Bee tank, there is simply not enough room for the clunk to move.

Another option is a ballon tank, there is no air in those (when filled correctly) so they don't care about orientation.

Co incidentally enough Kris the prop should be in the same parcel as
A NIB DFly from Bastiaan but 1, it's Nib and likely to stay that way.
2, I bet it's good old Cox Britellulike plastic so not like to survive long
With my flying 'style'.
3, naw to balloon tanks been there done that. Not my bag baby.

I'm going to cut end off a broomstick tomorrow and nail a B/W to it to see
How it runs whilst being rolled quickly.
Next post may be from the E.R.

Swing it like a Samurai, John!

If you're lucky they might just be able to stumble through a barrel roll, but usually a roll is a good way to intentionally stop the engine for a landing.

It sure sounds like a Dragonfly tank is what you need, but a Norvel tank and a TD engine might work too. Or simply use an external tank on the Bee by drilling a hole in the tank. That's how I did it some 30 years ago;

The plastic seems sturdier than delrin.

i was gona sugest a norvel tank/Tee Dee combo aswell but you aslo needa exhaust throtle...not available for TD as far as i know... but a RC carb is??

i have a cpl of spare norvel tanks if required but the cost of postage from here is prolly the killer

<<(is in australia)...Ga'day to all

Surfer_kris wrote:If you're lucky they might just be able to stumble through a barrel roll, but usually a roll is a good way to intentionally stop the engine for a landing.

It sure sounds like a Dragonfly tank is what you need, but a Norvel tank and a TD engine might work too. Or simply use an external tank on the Bee by drilling a hole in the tank. That's how I did it some 30 years ago;

I don't know if I should be impressed, intimidated, or ill looking at that.

How well did that exhaust rig work?

Phil

it prolly m,ade primeing the cly diffacult

The muffler comes appart for priming the exhaust, no problem. The external tank gives long and consistent runs, and with unaltered venturi the fuel draw is quite good.

john
i wouldnt hesitate going for an external tank. allows you to get the clunk working well, and for aero, allows you to mount it closer to CoG so flight characteristics dont change with fuel level(especially if big motor small plane, will be using more fuel relative to airframe weight).
if your using a carbon(or other) boom. take a look at the servo mounts used on heli tail rotor control(trex 250 etc) clamps the servo to the boom in any orientation.
http://www.rcsmart.com.my/webshaper/store/viewProd.asp?pkProductItem=2179
and lots of variations on this idea. simple, lightweight, and might give you some more room. (will also allow you to easily move servos closer to tail if you need to move CoG)

kris
what can i say.... love that pipe!!
how was its performance??

cheers
a

Seeing it is a take-apart I am quite impressed with it too!
Phil

John,

Why not wait and fly it on one of these?

https://i.imgur.com/8vgeA.jpg