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Is there such thing as a 30 deg pipe fitting?
- Thread starter AX-O
- Start date
AX-O
Well Known Member
I did that however, my engine is a narrow deck so the spacers that came with the fuel injection kit don't work. I had to make longer spacers, that moved the purge valve further outboard. My cowling sits right on top of the valve. I refuse to put a blister patch on my cowling. So I have to find another way.
frankh
Well Known Member
Could remote mount it but
the further the valve gest from the spider the less well it will work.
Any chance you could remake the the bracket where it bolts to the engine such that it angles the the whole thing downwards?
Come to theink of it I think I make have even chamfered the alu tubes such that it angled the whole thing downwards myself. You don't need much angle as the assembly is quite long.
Frank
the further the valve gest from the spider the less well it will work.
Any chance you could remake the the bracket where it bolts to the engine such that it angles the the whole thing downwards?
Come to theink of it I think I make have even chamfered the alu tubes such that it angled the whole thing downwards myself. You don't need much angle as the assembly is quite long.
Frank
frankh
Well Known Member
OK another idea
And Don at Airflow will probably get mad at me for this one but oh well..
So if you really want a 30 degree fitting..Simply remove the fitting thats there..Go down to your local hydraulic hose emporium and buy the same thing in steel (as opposed to stainless steel) cut the thing in half at the middle and grind a 10 to 15 degree angle on each cut face.
Then simply weld the two halves back together.
I have done this several times when I made fittings for my wingroot fuel pump system.
Somebody who is good with a TIG could probably do the same thing in SS, but I gas weld and carbon steel is what I'm comfortable with.
Of course you will have to adjust (or make new) the connecting bracket.
Perfectly feasible..if your not in a hurry you could cut it, send it to me and I'll weld it back up for you.
Frank
And Don at Airflow will probably get mad at me for this one but oh well..
So if you really want a 30 degree fitting..Simply remove the fitting thats there..Go down to your local hydraulic hose emporium and buy the same thing in steel (as opposed to stainless steel) cut the thing in half at the middle and grind a 10 to 15 degree angle on each cut face.
Then simply weld the two halves back together.
I have done this several times when I made fittings for my wingroot fuel pump system.
Somebody who is good with a TIG could probably do the same thing in SS, but I gas weld and carbon steel is what I'm comfortable with.
Of course you will have to adjust (or make new) the connecting bracket.
Perfectly feasible..if your not in a hurry you could cut it, send it to me and I'll weld it back up for you.
Frank
AX-O
Well Known Member
Talked with Don. He said I can remotely mount it on the other side of the engine (great idea). He said an 8 inch line or so would not make that much of a difference. By the way if you mount the purge valve remotely, you don't have to use stainless steel fittings. Alum AN fittings work fine. Don't ask me why. Thanks to all for the ideas.
frankh
Well Known Member
AX-O
Well Known Member
Do you guys have pics?
Have to go home and look but I will have to make some type of attachment just like the one for the spider/flow divider. I may be able to install the purge valve in a way that will make it easier to attach the control cable to it for operations. Have to go look at it some more.
frankh
Well Known Member
not specifically but here are multiple fittings welded together..pretty simple
http://img370.imageshack.us/my.php?image=short115ws0.jpg
http://img370.imageshack.us/my.php?image=short115ws0.jpg
Don Jones
Well Known Member
Welding
I for one am not comfortable with welded fittings on fuel, especially in a high vibration environment. I have seen too many professionally tig and gas welded things break on race cars and such from the vibration. Don at airflow doesn't come out and say it, but I will bet the requirement for stainless is because the aluminum fittings were cracking.
I for one am not comfortable with welded fittings on fuel, especially in a high vibration environment. I have seen too many professionally tig and gas welded things break on race cars and such from the vibration. Don at airflow doesn't come out and say it, but I will bet the requirement for stainless is because the aluminum fittings were cracking.
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frankh
Well Known Member
Of course each to their own level of comfort but and I can see how a sloppily TIG welded fitting could fail, but if its done with care there is no way such a fitting would break..for me I turn the gas down and oxy acetylene is a sloow process and this enables you to be sure you have proper flow into the joint.
I have hacksawed thru several of my test welds and they look like a single piece of steel..
If you take that approach then you would never hang an engine on an engine mount, let alone fly a rag and tube airplane as the whole fusalage is welded!..
As to the aluminium fitting..well yeah, its aluminium, not steel...But you can't compare that failure to a welded steel fitting as its waay stronger.
Frank
Don Jones
Well Known Member
Well....
I don't have a problem with welded stuff in general. My last race car was an all 4130 tube chassis that I tig welded together and it never broke. I also don't have any problem with the welds you did on your root mounted pumps. I just don't think a welded fitting should be used on a fuel component which is bolted to the engine (and shares some of the mounting loads as well). The risk of breaking is low, however, the results of the fitting breaking would almost certainly be a life threating event. The thing about welding something is not the weld its self, but what it does to the metal if it isn't done properly. Most fractures occur next to the weld in the original base metal and not in the weld.
Of course each to their own level of comfort but and I can see how a sloppily TIG welded fitting could fail, but if its done with care there is no way such a fitting would break..for me I turn the gas down and oxy acetylene is a sloow process and this enables you to be sure you have proper flow into the joint.
I have hacksawed thru several of my test welds and they look like a single piece of steel..
If you take that approach then you would never hang an engine on an engine mount, let alone fly a rag and tube airplane as the whole fusalage is welded!..
As to the aluminium fitting..well yeah, its aluminium, not steel...But you can't compare that failure to a welded steel fitting as its waay stronger.
Frank
I don't have a problem with welded stuff in general. My last race car was an all 4130 tube chassis that I tig welded together and it never broke. I also don't have any problem with the welds you did on your root mounted pumps. I just don't think a welded fitting should be used on a fuel component which is bolted to the engine (and shares some of the mounting loads as well). The risk of breaking is low, however, the results of the fitting breaking would almost certainly be a life threating event. The thing about welding something is not the weld its self, but what it does to the metal if it isn't done properly. Most fractures occur next to the weld in the original base metal and not in the weld.
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frankh
Well Known Member
Agreed
I certainly understand your caution and its well founded..certainly you don't give this fitting to the kid next door who's just got an arc welder for last Christmas..
Thats what I mean by improper procedures..Mose welds get crsytaline when they are cooled too fast so I play the torch over the weld a little to bring it down slowly and don't have any cold drafts going through the shop...Standard procedure for any A&P who should be able to weld up an engine mount.
The weight of the valve is low but the weight should be taken by the bracket anyway..I.e not the fitting..As Bob pointed out fittings are not really intended to take structural loads..But flex hydraulic hoses (which weigh a lot when full) are hung off the end of these fittings all the time on bulldozers and the like.
I think in this case its a perfectly acceptable application and the fact the fitting is welded or not (providing its done correctly) is neither here nor there. I mean think about it..the engine is hung off of welds..same high stress environment with a lot more load than this fitting will ever see.
Add to that an aluminium fitting has been used in this application with sucess until recently and the fatigue resistance of an 1/4" alu fitting will pale compared to a similar steel fitting, welded or not.
its just not an issue in this application I think.
Frank
I certainly understand your caution and its well founded..certainly you don't give this fitting to the kid next door who's just got an arc welder for last Christmas..
Thats what I mean by improper procedures..Mose welds get crsytaline when they are cooled too fast so I play the torch over the weld a little to bring it down slowly and don't have any cold drafts going through the shop...Standard procedure for any A&P who should be able to weld up an engine mount.
The weight of the valve is low but the weight should be taken by the bracket anyway..I.e not the fitting..As Bob pointed out fittings are not really intended to take structural loads..But flex hydraulic hoses (which weigh a lot when full) are hung off the end of these fittings all the time on bulldozers and the like.
I think in this case its a perfectly acceptable application and the fact the fitting is welded or not (providing its done correctly) is neither here nor there. I mean think about it..the engine is hung off of welds..same high stress environment with a lot more load than this fitting will ever see.
Add to that an aluminium fitting has been used in this application with sucess until recently and the fatigue resistance of an 1/4" alu fitting will pale compared to a similar steel fitting, welded or not.
its just not an issue in this application I think.
Frank
