VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Model Specific > RV-7/7A
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #21  
Old 06-07-2017, 02:24 PM
Kyle Boatright Kyle Boatright is offline
 
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 2,846
Default

Isn't the other option that the fuel is going out the drain tube?
__________________
Kyle Boatright
Atlanta, GA
2001 RV-6 N46KB
Reply With Quote
  #22  
Old 06-07-2017, 03:11 PM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 4,531
Default

Just a note to Alex: In Alaska and other cold places without heated hangars, it is not uncommon for aircraft to have a system where they deliberately add gas to the oil, at shut down. The next (very cold) morning, they can crank the engine because the diluted oil is so thin. As the oil warms up, the avgas evaporates away. Of course I have no idea where your avgas is actually going, but out the oil breather is possible.
Reply With Quote
  #23  
Old 06-07-2017, 07:32 PM
DNeufeld DNeufeld is offline
 
Join Date: Aug 2016
Location: Coeur d Alene
Posts: 31
Default

So an easy way to determine if the diaphragm is leaking would be to install a vented collector on the fuel pump drain tube and go for a ride or ground run it. Nothing in it, it's not leaking. Right?
Maybe I missed it in an earlier post. Have you tested the fuel for ethanol?
__________________
Dues paid 2017

Last edited by DNeufeld : 06-07-2017 at 07:36 PM.
Reply With Quote
  #24  
Old 06-08-2017, 06:11 AM
BillL BillL is online now
 
Join Date: Sep 2007
Location: Central IL
Posts: 3,916
Default

Quote:
Originally Posted by ALMARTON View Post
Considering those do you still think it may be the fuel pump leakage the main reason for high fuel consumption?
My guess is yes, leakage was the major loss, then loss to the oil. It is a fact your diaphragms were leaking, so with replacement of the pump, it is a good time to recheck the flight fuel burn, and airspeeds. It is always possible for multiple things to be occurring, so a new baseline with the new pump is in order before taking additional action unless there is direct evidence of an issue.

If a lot of fuel was being lost to oil and evaporating, then an oil change would be warranted too.

Please report the performance at 2700, WOT and altitude conditions, with new pump.
__________________
Bill

99% at the hangar now
Reply With Quote
  #25  
Old 06-08-2017, 09:17 AM
JonJay's Avatar
JonJay JonJay is offline
 
Join Date: Jan 2007
Location: Battleground
Posts: 3,566
Default

Quote:
Originally Posted by Kyle Boatright View Post
Isn't the other option that the fuel is going out the drain tube?
Possibly, but that orifice is super tiny. I am not sure you could push that much fuel out of there but perhaps.
The OP stated there was fuel in the case. For fuel to get into the case, both diaphragms would have to be compromised. It is unlikely that the upper diaphragm would fail first, but I guess it is possible. More than likely it was the lower one and it was simply not noticed in preflight for a very long time before the upper burst.

I had a diaphragm failure and it was very obvious during preflight with the tell tale blue stain coming out of the drain, but it was a very small streak of fuel.

Check your fuel pump drain on every preflight folks.
__________________
Smart People do Stupid things all the time. I know, I've seen me do'em.

RV6 - Builder/Flying
Bucker Jungmann
Fiat G.46 -(restoration in progress, if I have enough life left in me)
RV1 - Proud Pilot.
Reply With Quote
  #26  
Old 06-08-2017, 10:34 AM
ALMARTON ALMARTON is offline
 
Join Date: Mar 2010
Location: BRAZIL
Posts: 130
Default INFO UP TO DATE

Quote:
Originally Posted by BillL View Post

My guess is yes, leakage was the major loss, then loss to the oil.
It is a fact your diaphragms were leaking, so with replacement of the pump, it is a good time to recheck the flight fuel burn, and airspeeds.
It is always possible for multiple things to be occurring, so a new baseline with the new pump is in order before taking additional action
unless there is direct evidence of an issue.

If a lot of fuel was being lost to oil and evaporating, then an oil change would be warranted too.

Please report the performance at 2700, WOT and altitude conditions, with new pump.
Yes I also think the main part of the fuel was leaking through the drain into the atmosphere, some
inside the engine but most outside.

I also think there are fuel burn problems associated , because of great fuel flow variation in cruise
indicated in the gauges.

The aircraft engine a ENGINE LYCOMING YIO-360-M1B 180HP SERIAL EL - 36628 - 51E WITH HORIZONTAL INDUCTION
is at the moment at the shop being service, things they will do:

- Replace fuel pump (damaged as in the pics: https://goo.gl/photos/bZpgHHfAyQjByk728).
Installing a new Lycoming 62B26931 fuel pump
- They will change the oil and filter
- Clean and inspect the fuel filters and lines
- Clean nozzles
- Inspect Divider : AVSTAR AVX 3015004-1 and fuel injector system FUEL INJECTION AVSTAR AVX-5VA1.
They ALREADY have some test data on that and told me the AVSTAR fuel injection were way out of max pph in
idle in WOT regimes , they are looking if it is only a question of recalibrating it to standards
- Inspect the mag ignition timing as very well stated/reminded by rv7charlie in this post
- Oil collected for lab analysis for lead , etc. There is a oil analysis history I wil post here
afterwards

I'm confident that all that done I will gain a bit of power to attain the normal performance for a RV
(most likely) and that is sure that will solve fuel consumption issues.

By the way does anyone have tech data on the AVSTAR injections I quoted? Either the tech manual or
AVSTAR manufacture contatc email for me to ask. The shop here in Brazil is used to is having trouble
getting it (technical manual for it, they are only used with BENDIX/ PRECISION RSA 5AD1 and others
mainly certified ones... That would help.

As one more piece of information for your analysis this airplane always operated with temps and
temperatures inside green arc - more to the cool side than to the hot spectrum of the green arc.
Since new it got cooler and cooler with time but always on green arc, oil pressures logging a
drop in its history but always within operation limits. Fuel pressure always very high and steady
about 29 psi. Fuel flow always erratic and fluctuating a lot during any phase of flight.

Drop in both magnets on pre flight checks where always about 90 rpm and equal on each.
Always used 100/130 LL AVGAS from what I believed to be reputed dealers can't affirm it anymore though.

Data log since new (all but the last 4 hours - the coolest ones): http://cirrusreports.com/flights/PRZTI

rv&charlie and rzbill I was a bit mistaken on describing the power settings , the G3X Garmin is calibrated
ok, the numbers was what I described wrong. Poor memory... don't worry with that. WOT best power (TAS adjust
mix) maximum at pressure altitude 6500ft = density altitude 8000 this day about only 155kts TAS with a fuel
flow in 14,6 gal/h range...that's the average history. Sometimes worse some slight better consumption numbers
but never faster than 155kts though. 147kts is a number I could rely on attain any day anything more was
depending on the conditions of the day.

Quote:
Originally Posted by airguy View Post
I'm not saying that all your fuel went into the crankcase instead of being burned as a rich mixture.
I'm saying that it's entirely possible that a good portion of it went into the crankcase and evaporated
out without you noticing it.

Yes, it will dilute the oil, but not necessarily to the point that you'll notice increased oil
temperature during operation. In fact, the opposite may be true to some degree - until you reach a point
of dilution where increased friction causes increased heating, you'll actually see a lower temperature
on the oil due to the cool fuel diluting it and the evaporation of that fuel carrying away heat.
Quote:
Originally Posted by N427EF View Post
I think you nailed it, particularly where you state that evaporation causes cooling.
I DO THING airguy nailed also , great piece of info all of them , about oil system, pump and ventilation. And
the cooling through evaporation. Excellent diagnoses/explanations.

With all that I think the problem performance and fuel consumtion was in order of cause:

1 - leakage throgh pump drain to the atmosfhere (firt diafragm rubber failure with maybe 100h)
2 - injection system pouring to much fuel into the cilinders (service shop bench test data today
confirmed they were out limits rich, but can't precise to what extent it would overall afect the high consumption)
3 - possible bad mag timming (2 and 3 causing a poor burning and excess gas being expelled through exhaust and some washed up into crankcase)
4 - latter in engine operation life from 100h to today 143h (1,8 years time spam) the second diafragm rubber in
the fuel pump failed/rupture leaking also some gas into crankase (can't precise it in time or quantities and its
relative contribution for the consumption problem)

All that summing up to a bad performance (in speed) and gas consumption about 15% - 20% mored than standard in
any regime.

**Bear in mind that up to 100h I was in engine break-in phase so operating almost WOT full rich and so unable
to give normal consumption numbers. After that I started to go 100-50 ROP or even 50 LOP (under 60%) to
see consumption and started to have some doubts about engine health.

It does have a lot of take off power though... strangely it used to take off with less runway than other rv7s I operate.
But cruise was bad and range was limited due to consumption to 389nm with very litte reserve (about 20 min reserves).

Quote:
Originally Posted by Leadnuut View Post
So an easy way to determine if the diaphragm is leaking would be to install a vented
collector on the fuel pump drain tube and go for a ride or ground run it. Nothing in it, it's not leaking. Right?
Maybe I missed it in an earlier post. Have you tested the fuel for ethanol?
Too late for that... Pump was replaced. Never noticed outside clues of it... But if you seen the pictures
(link above) of the replaced pump on its inspection you will agree that it sure was leaking (two enormous rips).

Quote:
Originally Posted by BobTurner View Post
Just a note to Alex: In Alaska and other cold places without heated hangars,
it is not uncommon for aircraft to have a system where they deliberately add gas to the oil, at shut down.
The next (very cold) morning, they can crank the engine because the diluted oil is so thin. As the oil warms up,
the avgas evaporates away. Of course I have no idea where your avgas is actually going, but out the oil breather is possible.
Great to know BobTurner it gives me a peace of mind that the leakage into crankase ought not to have
caused permanent damage ( as temps were always so cool)

Quote:
Originally Posted by BillL View Post
My guess is yes, leakage was the major loss, then loss to the oil.
It is a fact your diaphragms were leaking, so with replacement of the pump, it is a good time to recheck
the flight fuel burn, and airspeeds. It is always possible for multiple things to be occurring, so a new
baseline with the new pump is in order before taking additional action unless there is direct evidence of an issue.

If a lot of fuel was being lost to oil and evaporating, then an oil change would be warranted too.

Please report the performance at 2700, WOT and altitude conditions, with new pump.
Yes as soon as the repairs finishes and I get to flight testing it I will keep you posted. I really hope
to bring only good news and numbers... Hope the darn AVSTAR can get fixed. Too bad if I have to buy a new
one... This engine from new mind you. Bought zero hours in Lycoming had with 143 hours all kinds of problem!
To bad for their reputation. At least with this pilot that writes you. Forgot to say that I got it with
ZERO compression in one of the cilinders , that were replaced in guarantee with 25 hours because of that.


Quote:
Originally Posted by JonJay View Post
Possibly, but that orifice is super tiny. I am not sure you could push that much fuel out of there but perhaps.
The OP stated there was fuel in the case. For fuel to get into the case, both diaphragms would have to be compromised.
It is unlikely that the upper diaphragm would fail first, but I guess it is possible. More than likely it was the lower one and it was simply not noticed in preflight for a very long time before the upper burst.

I had a diaphragm failure and it was very obvious during preflight with the tell tale blue stain coming out of the drain, but it was a very small streak of fuel.

Check your fuel pump drain on every preflight folks.
Your theory would spoil mine... but you may be right.


Now the compressions are ok 78/80 psi on all cilinders, I hope that I will get it as a NEW LYCOMING ENGINE
should be.

Its just too bad luck for one man and such a new engine at a time.

Thanks again all help... If anyone has tech info on AVSTAR or their contact (I don't reside in US) please would be of great help also.

Keep you posted .
__________________
Alexandre "neck" Marton
Brazil
RV7A (8/2015 built by FLYER)
Lycoming 180 HP - YIO-360-M1B, Hartzell C2YR-1BFP/F7497 72, Garmin panel - G3X Touch, GTN650, GTS800, WX-500, BATT CONCORDE RG-25XC AEROBATIC SEALED.
-------------
Others: RV9A
Lycoming XIO320-D1A, Hartzell HC-C2YL-1BF/F7663-4 , CS GOVERNOR MTV-12-B, DYNON D180
AND GARMIN AVIONICS
(Sold with aprox 300hrs flown from Dec/2010 -- JUN/2014)

Last edited by ALMARTON : 06-08-2017 at 10:43 AM.
Reply With Quote
  #27  
Old 06-08-2017, 11:46 AM
Bubblehead's Avatar
Bubblehead Bubblehead is offline
 
Join Date: Jul 2007
Location: Keller, TX
Posts: 1,504
Default

Almarton 0 this statement does not make sense.

"WOT best power (TAS adjust mix) maximum at pressure altitude 6500ft = density altitude 8000 this day about only 155kts TAS with a fuel
flow in 14,6 gal/h range...that's the average history. "

You cannot be at best power if you are burning 14.6 gph. My RV-8 with IO-360 fuel injection 180 hp burns about 8.5 gph max power at 8000 ft density altitude. I do not think 6 gph is going into the oil. I would expect about 160 KTAS at that point. My RV-8 is not especially clean aerodynamically but 160 is not bad.

I've not read all the posts to see if EGTs are reacting to leaning the mixture. Have you yourself as pilot leaned the mixture to find peak EGT? If you did and it is burning 14.6 gph something is wrong. Probably the fuel flow transducer is not properly calibrated. Have you verified it by recording total fuel consumption for a flight on a full tank, and comparing total calculated fuel consumed with gallons pumped to refill the tank?
__________________
RV-8 180 hp IO-360 N247TD with 10" SkyView!

VAF Donation Made 7/2017 ------ "It has taken us this long just to get where we are!"
Reply With Quote
  #28  
Old 06-08-2017, 11:54 AM
ALMARTON ALMARTON is offline
 
Join Date: Mar 2010
Location: BRAZIL
Posts: 130
Default

Quote:
Originally Posted by Bubblehead View Post
Almarton 0 this statement does not make sense.

"WOT best power (TAS adjust mix) maximum at pressure altitude 6500ft = density altitude 8000 this day about only 155kts TAS with a fuel
flow in 14,6 gal/h range...that's the average history. "

You cannot be at best power if you are burning 14.6 gph. My RV-8 with IO-360 fuel injection 180 hp burns about 8.5 gph max power at 8000 ft density altitude. I do not think 6 gph is going into the oil. I would expect about 160 KTAS at that point. My RV-8 is not especially clean aerodynamically but 160 is not bad.

I've not read all the posts to see if EGTs are reacting to leaning the mixture. Have you yourself as pilot leaned the mixture to find peak EGT? If you did and it is burning 14.6 gph something is wrong. Probably the fuel flow transducer is not properly calibrated. Have you verified it by recording total fuel consumption for a flight on a full tank, and comparing total calculated fuel consumed with gallons pumped to refill the tank?
I Know! You did not understand me. Let me explain better.

To my knowledge best power adjust "by the book" should be somewhere at 50 to 100ºF Rich of Peak EGT

But as my airplane engine is not behaving normal... SO my best power adjust was based in results not standards.

What I did was go WOT full rich 2700 rpm and fiddling with the mixture until I got the best TAS speed possible 155kts but it was attained with an enormous consumption... that's it.

Can't see where it was wrong (best power = best performance speed) and the difference in numbers from that to an normal engine settings shows symptoms to how different my engine problems are to
corroborate to a diagnose.
__________________
Alexandre "neck" Marton
Brazil
RV7A (8/2015 built by FLYER)
Lycoming 180 HP - YIO-360-M1B, Hartzell C2YR-1BFP/F7497 72, Garmin panel - G3X Touch, GTN650, GTS800, WX-500, BATT CONCORDE RG-25XC AEROBATIC SEALED.
-------------
Others: RV9A
Lycoming XIO320-D1A, Hartzell HC-C2YL-1BF/F7663-4 , CS GOVERNOR MTV-12-B, DYNON D180
AND GARMIN AVIONICS
(Sold with aprox 300hrs flown from Dec/2010 -- JUN/2014)

Last edited by ALMARTON : 06-08-2017 at 11:57 AM.
Reply With Quote
  #29  
Old 06-08-2017, 12:07 PM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 2,154
Default

Alexandre,
Your 1st report specified 2500 rpm; your most recent says 2700 rpm. Did you re-fly the test, or mis-state the rpm in the 1st report?

Bubblehead,

Run your numbers. If you're making 75% on a 180 HP Lyc and only burning 8.5 GPH, you just need a couple more events for it to be the 1st Lyc qualified for sainthood. That would be .377 BSFC. Extremely unlikely with a stock Lyc.

Charlie
Reply With Quote
  #30  
Old 06-08-2017, 12:47 PM
ALMARTON ALMARTON is offline
 
Join Date: Mar 2010
Location: BRAZIL
Posts: 130
Default

Quote:
Originally Posted by rv7charlie View Post
Alexandre,
Your 1st report specified 2500 rpm; your most recent says 2700 rpm. Did you re-fly the test, or mis-state the rpm in the 1st report?
Kinda ignore first report . It has some confusion in the power percentages .

But trying to assert better it I do think , if I recall right, that WOT full rich with 2500 or 2700 rpm and adjusting mixture to attain the highest TAS possible I'll have only slight different results from 151kts (2500rpm) to 155kts (2700 rpm)

They just called my the injector servo had a broken spring, it being replaced and recalibrated. They will check now flow divider and nozzles. After reassemble in the engine and do mag timming ignition checks. By 24th I expect to go flight test it and fetch the airplane. They will do , off course, some ground tests.

I'll keep posting here the updates and data. Expecting a complete new performance now! Very Optimistic!
__________________
Alexandre "neck" Marton
Brazil
RV7A (8/2015 built by FLYER)
Lycoming 180 HP - YIO-360-M1B, Hartzell C2YR-1BFP/F7497 72, Garmin panel - G3X Touch, GTN650, GTS800, WX-500, BATT CONCORDE RG-25XC AEROBATIC SEALED.
-------------
Others: RV9A
Lycoming XIO320-D1A, Hartzell HC-C2YL-1BF/F7663-4 , CS GOVERNOR MTV-12-B, DYNON D180
AND GARMIN AVIONICS
(Sold with aprox 300hrs flown from Dec/2010 -- JUN/2014)
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 05:36 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.