Hose question

[jamesm]

I am having a discussion with another A&P & IA about hoses.  Had fuel pressure line  from carburetor to fuel pressure transducer on the engine monitor  CGR30 which is -2 diameter hose. it a -2 at carb and it's a -2 at the pressure transducer. the hose  started spraying to confirm it really was the hose, we removed it plugged one end and blew air soapy water and watched the soap bubble.  I have been down road a gazillion times but found no real definitive answer.  both the manifold pressure line and fuel pressure line off the carburetor has -2 fittings. problem is that the so called fuel rated hose material doesn't really start until you get to -3  diameter and larger diameters. If you use Aluminum line it work hardens I have happen to me twice. IMHO it would be stupid to run fuel through in such a small of diameter which would break frequent .  I suppose you put couplers and  reducers and enlargers  and you would have about 1/2 foot of fittings pron to leak. Maybe it's done out in field but I would suspect I would seen it all people 's pictures of their plane  photos. If  I look at Parker page the 193 hose is for vacuum and air on Mcfarlane web site. I have found plenty of Hose material compatible of supporting Fuel and Oil by haven't found one that supports that is -2 diameter  hose diameter. . What Guidance do I have or where would I go to find -2 diameter hose material that supports "Fuel".

Please advise,

James '67C

[N201MKTurbo]

Call a hose shop. 
 

If you look in the Stratoflex catalog, it shows all the different hose/fitting combinations.

[N201MKTurbo]

What does the IPC call for?

[jamesm]

I can't find it for such a small diameter.

 

[jamesm]

Here is what I found… https://aircrafthosestore.com/pages/how-to-choose-an-aircraft-hose

as expected no -2 hose are made for fuel pressure line from carburetor to fuel pressure gauge. I tried to find it in the Mooney maintenance manual and IPC. No luck

[N201MKTurbo]

28 minutes ago, jamesm said:

Here is what I found… https://aircrafthosestore.com/pages/how-to-choose-an-aircraft-hose

as expected no -2 hose are made for fuel pressure line from carburetor to fuel pressure gauge. I tried to find it in the Mooney maintenance manual and IPC. No luck

That is a tiny fraction of what’s in the Stratoflex catalog.

[Fly Boomer]

12 hours ago, jamesm said:

I can't find it for such a small diameter.

According to the Statoflex catalog, 124-3 is about a quarter-inch OD.  Yours is smaller?

[jamesm]

Yes if I recall correctly that the original fuel pressure/ manifold pressure gauge, used a -2 fittings on gauge and the firewall fittings to respective sources.  The manifold pressure gauge used an aluminum line (right/ wrong or indifferent) at least since the time the plane has been in the family since 1984. 

[Gee Bee Aeroproducts]

Milh5593 is not approved for fuel and oil .

I suggest and I have designed a female -2 to step -3 flare adapter for firewall

Then change fitting on carb to alloy -3

Next , I build tso Teflon hose -3 to your spec.

Firesleeve Black or Blue

I designed this for 1947 to 1971 Beechcraft models -2

oil psi

Fuel Psi

manifold psi

I have been designing hoses and adapters tso since 1987.

Iam the only tso PT6 hose supplier for aftermarket.

i dont do anything based on cost only quality.

 

last picture is tio541

20 hose assys

4775.00

i have to mfg the prop accumaltors next week .

these are engine

not airframe to engine 

 

 

 

Edited Wednesday at 09:52 PM by Gee Bee Aeroproducts

[N201MKTurbo]

https://www.parker.com/us/en/divisions/stratoflex-products-division.html
 

https://aircrafthosestore.com/pages/current-catalogs

 

[Gee Bee Aeroproducts]

Just a follow up

I can mfg a tso -2 Teflon , but the fittings are expensive, changing to -3 is half the cost .

Iam doing a -3 fuel vent tomorrow 

Gauge to firewall 

Firewall to baffle 

This is in case of fuel gauge failure and fuel goes overboard.

cost is 477.50 with anti chafe .

 

 

[jamesm]

How do I deal with fitting coming off the carburetor for fuel pressure line? it's a  -2 flare 90 degree  looks to be a aluminum ( blue) fitting. 

The current installation doesn't go through the firewall.  it  has a ~ 25"  long  -2 hose going into an EI CGR30C/P pressure transducer  which of course has a male fitting to a -2 hose flare fitting.  mounted on one of Engine mount tubes.

Can the carburetor fitting be aluminum? same with the EI transducer should be steel or aluminum or ???

 

Thanks for all the input.

James '67C

Edited Thursday at 08:41 PM by jamesm

[N201MKTurbo]

How about some pictures of what you have.

[Gee Bee Aeroproducts]

I stock

45 and 90 elbow -3 adapters

If you don't understand, consult your mechanic.

[Gee Bee Aeroproducts]

2 hours ago, jamesm said:

How do I deal with fitting coming off the carburetor for fuel pressure line? it's a  -2 flare 90 degree  looks to be a aluminum ( blue) fitting. 

The current installation doesn't go through the firewall.  it  has a ~ 25"  long  -2 hose going into an EI CGR30C/P pressure transducer  which of course has a male fitting to a -2 hose flare fitting.  mounted on one of Engine mount tubes.

Can the carburetor fitting be aluminum? same with the EI transducer should be steel or aluminum or ???

 

Thanks for all the input.

James '67C

The adapter screws on the -2 bulkhead fitting to convert to -3

hose Assy 

[Kelpro999]

193-2 is listed in Mooney parts manual. -2 is easy to assemble, light weight and meets minimum bend radius requirements for easy install. Hose specifications has me concerned also so it’s on a replacement schedule. 

[Gee Bee Aeroproducts]

4 minutes ago, Kelpro999 said:

193-2 is listed in Mooney parts manual. -2 is easy to assemble, light weight and meets minimum bend radius requirements for easy install. Hose specifications has me concerned also so it’s on a replacement schedule. 

Read the mil spec

193-2

306-2

milh5593

not for fuel and oil 

Safety is inexpensive.

[Kelpro999]

13 hours ago, Gee Bee Aeroproducts said:

Read the mil spec

193-2

306-2

milh5593

not for fuel and oil 

Safety is inexpensive.

 $25 and 15 minutes every few years seems to work okay. 

[cliffy]

I remember I went down the rabbit hole on this exact subject a few years ago

I found by reading the actual MIL spec (attached) that 193-2 hose (to MIL spec MIL-H- 5593) actually 

had to pass some hydrocarbon testing using hot MIL-5606 fluid.

Its contained in section 4.4.3.7  attached below

file:///C:/Users/72773/Downloads/MIL-H-5593C%20(1).pdf

It shows as a non-secure download but it down loads OK on my computer when forced

Just for a point of reference- maybe why Mooney used it   Its an old MIL spec

I do like the idea of upsizing to #3 hose though

[Skates97]

19 hours ago, jamesm said:

How do I deal with fitting coming off the carburetor for fuel pressure line? it's a  -2 flare 90 degree  looks to be a aluminum ( blue) fitting. 

The current installation doesn't go through the firewall.  it  has a ~ 25"  long  -2 hose going into an EI CGR30C/P pressure transducer  which of course has a male fitting to a -2 hose flare fitting.  mounted on one of Engine mount tubes.

Can the carburetor fitting be aluminum? same with the EI transducer should be steel or aluminum or ???

 

Thanks for all the input.

James '67C

Be careful with that fitting on the carburetor, it has a reducer inside it and is expensive. When I had my engine replaced a year ago it was broken. I replaced that hose I think during annual in 2024, I can check my logbooks to see what was used this weekend.

[jamesm]

This is what I found so far I  could be a stretch but   according to Mooney's Parts catalog that I have (see attached for photos as well) calls for AN6270-2-35 (#30 Part Cat). I am assuming ... -35 is length in inches and -2 is diameter of the hose.

Application:

Air or vacuum instrument systems, automatic pilots, and lines to pressure gauges used with these systems as specified in MS33620. Hose assemblies conform to AN6270. Hose conforms to MIL-DTL-5593. Fittings conform to MIL-DTL-38726 and MS27404. Supersedes AN773

For 306 

am I missing something? I know the Eaton 306 vacuum and pressure lines but since Mooney calls it out in there Parts catalog does make valid to use 306 Hose?

Thanks again for all the input and sorry for beating a dead horse over and over. I needed a reality check.

James '67C

carb_pressure_line.pdf

[Gee Bee Aeroproducts]

Read the mil spec of the hose 

mil H 5593

Rubber 

Copper was used in most -2 fuel psi applications.

The problem is it ages out 

From 1972 on up Beechcraft uses -3 on oil and manifold pressure 

-4 on fuel psi.

I have a Cnc bender to mfg 304 tubing 

There must be a flex hose on both side of a fuel transducer.

what was done in the past is not how it is done today.

Iam asked to design these brackets and tubes by various shops for installations.

 

 

 

[Skates97]

Checked the log entry, Stratoflex 193-2 was used, cut to length and ends installed. Spruce says it is not rated for fuel, McFarlane says "designed to withstand most aircraft fuel, oil, coolants, solvents,"

https://www.mcfarlaneaviation.com/products/193-2/?srsltid=AfmBOoro-aCvjgIVazwt5eDcDAtYm7lg2s_WWXCVvHJ4fh9kwkkTfnHf

https://www.desserhoses.com/dtr_hose_types_sizes.html#:~:text=Desser Hoses - Hose Types and,optioned with orange type firesleeve.

There's this old post from Clarence saying the IPC shows 193-2. The IPC calls for AN6270-2 which according to Dresser is is MIL-H-5593 and is also 193. Sure miss having Clarence around.

 

[Gee Bee Aeroproducts]

I only use rubber with clear shrink on early model master cylinder hoses as there is a clamp to attach the hose socket to airframe.

90% of the hoses we ship are tso Teflon in custom colors or shrink.

 

 

I stock all beech landing gear hoses / new master cylinders / hardlines and we always send new adapters .

 

PT6 hoses are 4775.00 to 9775.00 each / TSO Titeflex 

Since 1993 

I sell quality, not price

Other hose shops are limited on there capability based on there tso .

Aeroquip

Stratoflex

They cannot mfg PT6 hoses as there not tso spec from Pratt Whitney.

When all else fails, read the milspec and tso .