RC11

My Feedback: (7)

Any recomendation for gasoline tubing?
RC

MTK

Yes, one type is head and shoulders better than anything else we can put in for gasoline. For inside the tank, Viton is the best and is also 10x the cost. I am using 60 durometer which is soft. The 75 durometer is fine for outside the tank but a bit stiff for inside

For outside the tank, I use Nitrile, but you can't go wrong with Viton there too. I have also used neoprene (LHS will carry this material)but didn't care for it. It cracked in only a couple months. Nitrile, neoprene, and the many varieties of Tygon, all will need replacement annually, and neoprene more often than that. Viton will not need replacement for many years.

Point is that you have few options....the best type will set you back around 3.5-4$ per foot.

BTW- I am also experimenting with PUR to find how this material will work. All this stuff will eventually find its way into our cookbook recipe

RC11

My Feedback: (7)

Matt,
Where do you get Viton and what clunk are you running?

Slightly off subject but..... People think the clunk and clunk line must be able to follow fuel and be able to bend in a downline to go to the front of the tank. I don't think this is possible. If you have ever dinked one in and the clunk is in the front of the tank, it can be difficult get the fuel line and clunk beat around back to it proper possition in the back of the tank. So I am doubting the clunk is that mobile. If you hold your plane nose down and look at the clunk it will at best bend to the upper limits of the tank. What are the dynamics of fuel and the clunk in a downline? I gots to know!!!

Thanks Proffessor,
RC can other classmates chime in also?

ghoffman

My Feedback: (3)

It sounds like a good idea to keep it filled before each flight, even if you think you have enough for the last 10 minute flight of the day.

MTK

The easiest source is McMaster Carr since it is offered in as little as 5' lengths. There are several other sources on the internet.
I tend to get most supplies like these from McMaster Carr. They also carry the other tubing types I've talked about here-in.....Teflon PTFE, neoprene, nitrile, silicone and fluorosilicone, and PUR (polyurethane). They carry soooo many things useful to us in modeling

Yes quite right. When the nose is pointed straight down, the clunk does not necessarily follow the fuel unless the clunk is very heavy and the pick up line very soft. If the engine is at full and the vertical down line extended, then you could hear some cutting out. hard to do that tho because the vert line would have to be very long; not realistic

My tank's clunk is the standard weight that comes with DuBros.

cmoulder

Hi, Rick,

I agree that the clunk is not all that mobile, nor should it be. When you think about it, when a model is descending (with engine at idle) the liquid in the tank is "feeling" virtually zero gravity, so neither the fuel nor the clunk are going to the front of the tank. However, I store my models in a small utility closet and I must store them with the spinner down, which means with soft fuel line the clunk can work its way to the front of the tank. This happened, and I lost a nice model (RC Guys Decathlon) because of it, so now for the fuel pick-up line I use a brass section in the middle so that there is no chance the fuel line can fall forward in the tank.

When I used to fly smaller aerobatic glow models and fling them about the sky, occasionally bubbles would get into the line and there'd be the occasional deadstick. I started using OS Bubbleless clunks and that was the end of that. The engine will run down to the last drop with no change in performance. I don't know if it's necessary for pattern, but that's what I use with all gas and glow fuel systems because it removes any doubt.

cmoulder

PS

Matt suggested McMaster-Carr and I second that motion.

They ship blazingly fast and they get it right. I always say that when I order something I could swear they put it in the mail before I ordered it.

tele1974

I would have to seconded that also about McMaster.  They are about 45 minutes from here and I have ordered in the AM and had the order on my door step that evening.    I too use the viton in the tank with the brass tube.  I had to learned the hard way a few times how to run a fuel system.  And, I am glad to here that you are getting good results with it.   My motor is on its way to Todd.  I fractured my main shaft.  Don't ask.  Just more of that hard way of learning. 

erieqc

Matt I was looking at the Viton and they only show the 70A soft is this what you are using [link]http://www.mcmaster.com/#viton-fluoroelastomer-tubing/=99nwbx[/link] and what size are you using.
Thanks Bill

RC11

My Feedback: (7)

Hey,
Just thinking??? Sometimes I do that??? If someone has one of the little video cameras and a clear canopy, they could settle the "What happens to the fuel and clunk in a downline question". It sure would be nice to really know for sure!
Thoughtfully yours,
RC

cmoulder

Good idea! Could be done with a Flip video on CG, which where the tank is located anyway!

MTK

Bill,

I use part number 5119K41.....1/8" ID x 1/4" OD, 60 duro

I am also looking at Urethane tubing, 5549K44.......1/8" ID X 3/16" OD. I have this tubing immersed in raw gasoline/oil mix for several days now. If it lasts a couple months without losing properties, it would be a good alternative. It is firmer than Viton at 80 Duro but it's thinner so flexibility isn't much of an issue. How flexible it remains after a couple months of continuous immersion waits to be seen.

RC11

My Feedback: (7)

I think I have the correct M.Carr # for the Nordlocks. 91812A227 Right? 5119K41 for the Viton fuel tubing ? Right?
Thanks,
RC

cmoulder

Rick, correct on the NordLocks for the header. M5 for the header bolts, M4 for the stand-off bolts if you decide to use them there, which I would recommend.

Don't know about the Viton variety. This is something I will undertake a bit later.

RC11

My Feedback: (7)

Thank you Bob. I'm ordering up some viton too.
RC

w8ye

My Feedback: (16)

<nobr>Part Number: </nobr>91812A227

<nobr>$7.01per Pack of 5 Pair</nobr>

<form name="idsFeatureValueChange" action=""> Shape Wedge Lock For Screw Size 10, M5 Material Type Stainless Steel Finish Plain Stainless Steel Type 316 Stainless Steel Inside Diameter .21" Inside Diameter Tolerance ±.012" Outside Diameter .35" Outside Diameter Tolerance ±.012" Minimum Thickness .09" Thickness Tolerance -.02" to +.01" Application Locking Washer Rockwell Hardness Minimum C51 Specifications Met Not Rated </form>

w8ye

My Feedback: (16)

RC11

My Feedback: (7)

Thank you for the verification. Well done. I ordered the right stuff!
Rick

MTK

Rick,

I use the zinc plated steel washers. Can't go wrong with either the stainless or the zinc plated. Zinc plated is less expensive that's about the only difference of interest

Matt

Shape > For Screw Size > Finish
Washers
This product matches all of your selections.

Part Number: 91074A112 $10.65 per Pack of 25 Pair
Shape
Wedge Lock

For Screw Size
5

Material Type
Steel

Finish
Zinc-Plated

Inside Diameter
.13"

Inside Diameter Tolerance
±.012"

Outside Diameter
.28"

Outside Diameter Tolerance
±.012"

Minimum Thickness
.07"

Thickness Tolerance
-.02" to +.01"

Application
Locking Washer

Rockwell Hardness
Minimum C44

Specifications Met
Not Rated

RC11

My Feedback: (7)

Thank you Matt!
RC

w8ye

My Feedback: (16)

There are two different outside diameters avaiable for the M4 Nordlocks?

MTK

W8, did you mean M5?

Yes it would appear that stainless has larger OD. It may not fit the header exhaust flange properly. Good catch!

Zinc plated steel washers have 0.28" OD which fits just right.

wildwillie3

Hi All,

I got to see RC11's plane fly saturday, lot's of power, easy start (one flip), very nice!


Bill

MTK

Well, I am very close to completing the epic build. Four years.... I know, I know, designer scale takes less time.

Anyhoo, here are a couple photos of some key details of the SAP 180 installation; The throttle and choke servos are DS281s. This set-up was started back in January. I posted some photos back then, around page 17 or 18. Servos and mounting weighed in at 25 grams. Having the servos essentially on the rotation axis of the soft mount should result in simple and clean actuation. The plastic push rods will transmit little movement to the servos.

I reduced spring tension on throttle by moving the spring to a different hole than stock. In essence, spring length was reduced

MTK

Nose ring on this engine turns out to be a simple job. The Hall sensor is located vertically in the SAP. Some engines have is set to the side and that tends to create a more difficult fit and set-up. Anyway, cutting 1/8" clearance around the sensor is not a big deal. Although I started this experiment with no nose ring, I came to realize over the first few dozen flights that the plane just wasn't behaving itself the way I was used to. Adding the nose ring cleaned the flight envelope; I recommend it if you soft mount the engine.

The ignition module mount was a gift from Todd. The least I could do is make good use of it.

BTW, the ignition wire and plug all fit neatly inside the cowl with about 1/4" clearance, as you can see in the photo above. That was not true for the ZDZ40 F3A. The cowl needed a clearance hole