Bladder Tank 10 Gallon Add-On

[rbridges]

1 hour ago, flyer7324 said:

Sorry C model here. But I usually fly above 8000 so I can get fuel flow down. (JPI 700 on board). Please provide me with your power settings/altitude.

 

He runs lean of peak, something we can't do very well in our C models (fuel injected vs carbureted).  

[ArtVandelay]

That and the J's aerodynamic improvements and angle valve engine make the difference. When LOP there are also no real power settings like you are used to using ROP that I can explain. You just set power by fuel flow. 

 

Can you explain how the angle valves make a difference in efficiency,

I thought they just allowed bigger valves and hence more HP?

[Hank]

1 hour ago, teejayevans said:

 

 

Try 8000-9000', 2200 RPM, FT, LOP...if you are at full gross, drop RPM down to 2000.

Yeah, that won't work for us C drivers--2200 is in the red zone (2000-2250 for me).

i generally do pretty well at altitude. Need to dip the tanks and see what I used coming here at 9000 msl at about 25° ROP last night. It was dark and I was tired last night . . .

[PTK]

I wonder what the bladders do to the resale value in view of the fact that they are irreversible and detract useful load. I guess it would depend on how the airplane is used as to how critical ul is?

[jetdriven]

I wonder what bladders do to resale value due to the fact they fix leaks permanently hence no risk of a future 8000$ reseal?  Also, never in the history of man has a group made such a big deal about 35lbs.  My J has a 967 lb useful load, with bladders.  What's yours, PTK?

[Piloto]

Flying high gives you longer range in no wind condition. But the reality is that there is always wind and weather. A higher power setting against headwind in many instances will give you better range. Best way is to compute range is to use ground speed instead of air speed.

José

[PTK]

Ot was just a question Byron!

Buf since you ask my ul is 176 pounds with full bladders and ~173 when empty! 

I've been told my resale value is high and getting higher by the day! It's highest with bladders  full!

[jetdriven]

4 minutes ago, PTK said:

Ot was just a question Byron!

Buf since you ask my ul is 176 pounds with full bladders and ~173 when empty! 

I've been told my resale value is high and getting higher by the day! It's highest with bladders  full!

Dentist math.  

[Hank]

2 hours ago, Piloto said:

Flying high gives you longer range in no wind condition. But the reality is that there is always wind and weather. A higher power setting against headwind in many instances will give you better range. Best way is The only way to compute range is to use ground speed instead of air speed.

José

FTFY.

[jetdriven]

2 hours ago, Piloto said:

Flying high gives you the same range in no wind condition. But the reality is that there is always wind and weather. A higher power setting against headwind in many instances will give you better range. Best way is to compute range is to use ground speed instead of air speed.

José

There. Fixed some more. Max conrad holds many long range records and all of them were set at low altitude. 

Also, ground speed has to get in the 100-110 knot range before flying faster becomes more efficient. 

Edited July 28, 2016 by jetdriven

[Piloto]

6 hours ago, Hank said:

FTFY.

Check with Charles Lindbergh, no ground references over the North Atlantic.

José

 

[Piloto]

7 hours ago, jetdriven said:

There. Fixed some more. Max conrad holds many long range records and all of them were set at low altitude. 

Also, ground speed has to get in the 100-110 knot range before flying faster becomes more efficient. 

As per Mooney POH Performance Chart the higher you go the longer the range.

Ground speeds in the 100-110 kts range are not rare when flying west bound during winter in the US, specially on an M20C doing 140kts against 30kts headwind. 

[Piloto]

1 hour ago, bluehighwayflyer said:

Sorry, Jose, but range increasing with altitude is a commonly held misperception, as is specifically confirmed by our POH. See and compare the attachments below for the max range available at economy cruise at sea level and 8,000', respectively, for example only.

Jim

Well per your own chart on the last two columns range appears to be longer for all equal power settings at 8,000ft. And for the M20R at 55% the difference from 2000ft to 12,000ft is 200nm. The higher the power plant the higher the range at altitude. Check the M20R POH Performance chart page 5-21. Same range at altitude may be applicable to low power planes (100hp) but not for 300hp planes.

BTW Max Conrad flew at low altitude for the same reason Lindbergh did, too much fuel weight to do any climbing.

José

Edited July 29, 2016 by Piloto

[Guest]

13 hours ago, jetdriven said:

There. Fixed some more. Max conrad holds many long range records and all of them were set at low altitude. 

Also, ground speed has to get in the 100-110 knot range before flying faster becomes more efficient. 

I was once told comparing Max Conrad's flights to a Mooney was wrong,  as he flew over gross weight and wasn't even in a Mooney.

He sure was a heck of a pilot though.

Clarence

[jetdriven]

Regarding those cruise power charts, where is the fuel used for the climb accounted for? So on the case of the 120nm extra range at 8000' and 2400 rpm and 156 knots, how much range do we subtract for the 6 gallons used in climb?

[Hank]

1 hour ago, jetdriven said:

Regarding those cruise power charts, where is the fuel used for the climb accounted for? So on the case of the 120nm extra range at 8000' and 2400 rpm and 156 knots, how much range do we subtract for the 6 gallons used in climb?

This is what's in my Owners Manual about fuel burn in the climb (see §1):

 

[Bob - S50]

I did quite a bit of playing with total fuel burn at cruise altitudes ranging from SL to 12,000' using book numbers and no wind.  What I found was:

1.  Out to about 200 NM it really doesn't matter what altitude you pick, the difference in burn will probably be less than 1 gallon.

2.  At about 300 NM, the edge goes to an altitude of 8000 - 12000 but the burn difference between that and SL is still less than 2 gallons.

3.  Way out at 800 NM:

     A.  The difference between SL and 12000 is about 7 gallons.

     B.  12000 is less than a gallon better than 10,000 and only about 2 gallons better than 8000.  That's only about a 4% difference it total burn.

To my mind, the best altitude is around 8000' +/-.  It is always competitive range wise.  It gives me a higher cruise speed than up high.  I find it is easier to keep the CHT's down because the air is thicker.  It's high enough to get above the thermal turbulence as long as it's 6000' AGL.  I don't spend forever in a high power, high noise, low ground speed climb.

Just my opinion of course.

Bob

[rbridges]

19 hours ago, PTK said:

I wonder what the bladders do to the resale value in view of the fact that they are irreversible and detract useful load. I guess it would depend on how the airplane is used as to how critical ul is?

I think it varies. Some people see bladders as a long term fix and feel it's worth the weight penalty. Others see it as a negative for the reasons you mentioned.  I remember garrison had bladders as a $1000 upgrade when appraising planes. Bottom line, I think it's a wash overall. 

[jetdriven]

On July 28, 2016 at 1:18 PM, PTK said:

Ot was just a question Byron!

Buf since you ask my ul is 176 pounds with full bladders and ~173 when empty! 

I've been told my resale value is high and getting higher by the day! It's highest with bladders  full!

Come on Peter, answer the question.  What's your useful load? Mine is 976 and that's with a WX1000 Stormscope, KN61 DME, and two KX170B radios, and yes, bladders.  

[PTK]

On July 29, 2016 at 8:11 PM, jetdriven said:

Come on Peter, answer the question.  What's your useful load? Mine is 976 and that's with a WX1000 Stormscope, KN61 DME, and two KX170B radios, and yes, bladders.  

Byron, this is not about the absolute value of my ul or yours! It's about the fact that once you go with bladders the airplane gains  the 40 pounds, or whatever the exact figure is, and can't go back. This may be important to some while others don't care. Depending on how ul critical the use of their plane is.

It will be a factor at resale that a potential buyer will have to consider. 

My Mooney is a perfect two place, full fuel and bags machine. If I wanted to be near gross and depending on weights it can be four place with some careful planning and modulating fuel quantity and bags. Those extra pounds would really help in the latter case. Yours being an early J does have a little higher ul.

But if you want to talk about absolute value of UL that's 35 or 40 pounds you don't have and can't never get back! 

My opinion is that there's no good reason to go to bladders knowing full well I'm permanently lowering my UL! I'd be condemning or handicapping a perfectly good airplane and I don't want to do that. If I'd do anything I'd much rather go with Monroy and give it extended range. 

 

 

 

 

[Bob_Belville]

I burned 52.4 gallons returning from KOSH Saturday. I chose to make a fuel stop, actually not a choice, but having the extra 10 gallons, I have the 54 gallon bladders, would have made non stop an option.

(I was @ 9000' burning ~8.3 GPH LOP most of the flight with no tail wind.)

I was able to do MRN-MSN non stop 7/22 with a head wind using 42 gallons with more direct routing.

So, I vaclilate. A human needs stop is not  bad thing.

[Piloto]

On ‎7‎/‎29‎/‎2016 at 7:18 AM, jetdriven said:

Regarding those cruise power charts, where is the fuel used for the climb accounted for? So on the case of the 120nm extra range at 8000' and 2400 rpm and 156 knots, how much range do we subtract for the 6 gallons used in climb?

If you descend at the same speed you climbed the fuel spent on the climb is recovered on the descent. The range tables allow for the fuel spent on the climb and the weight. But on an overweight condition climbing to high altitude is not practical. This is why the B747 and others do step climbing as they burn fuel for 10hrs flights.

José

[Bob_Belville]

4 hours ago, bluehighwayflyer said:

This has been my experience, too, Jose.  My total fuel burn per hour is consistently within .25 GPH of my cruise fuel burn per hour. 

+1

I usually climb at full throttle and about 120 kias. I reduce prop to 2550 and lean to ~ 200 ROP as I climb. The extra fuel is offset in the descent which is near red line conditions permitting.    

[ArtVandelay]

4 hours ago, bluehighwayflyer said: This has been my experience, too, Jose.  My total fuel burn per hour is consistently within .25 GPH of my cruise fuel burn per hour. 

+1

I usually climb at full throttle and about 120 kias. I reduce prop to 2550 and lean to ~ 200 ROP as I climb. The extra fuel is offset in the descent which is near red line conditions permitting.    

Your red line must be fairly low, I can drop 1000/min and stay out of the yellow.

[Bob_Belville]

42 minutes ago, teejayevans said:

Your red line must be fairly low, I can drop 1000/min and stay out of the yellow.

Yes, Vne (red line) in a vintage E is 164 kcas. Vno (top of the green) is only 130 kias. Below about 8000' our E models often cruise in the yellow.

(But we take some consolation knowing that our younger sisters have different ASIs and very few structural changes - e.g. ribbed elevator surfaces.)