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Speed Mods

Brian Scranton
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Brian Scranton Proficient

Brian Scranton

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So, I've been flying a lot lately. Maybe 75 hours in the last 3 months. Mostly with the family, dog, gear, high, hot, heavy...and I have found that my speed is consistently around 138-144KTAS in my turbo-normalized 1975 M20F (RayJay), running 24/2450, 12gph (100 ROP on the TIT) at 10,000-16,000ft with a VSI of 300-450 between 6000 and 12,000. 

Today I made a few speed mods. I left the wife, kid, dog and gear at home--and screamed up to 16,000 averaging 600-700fpm. Cruise was 148KTAS, 24/2450, 12gph ROP.

I get it. Weight makes such a huge difference. Not ready to drop carbs from my diet yet, but I am close. 

 

 

 

 

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carusoam Grand Master

carusoam

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Keep in mind.,.

Weight in the front seat is going to be more drag than weight in the back seat.

Drag is induced a couple of ways...

1) Adding weight at the center of lift will cause the need for an increased AOA to generate the added lift required to maintain level flight. The increased AOA will generate more drag....

2) Adding the same weight in the front seat not only increases the AOA but the tail plane has to be trimmed to pull more downforce to counteract the balance challenge...  weight + extra downforce = even larger change of AOA.....

Or so I was told....

PP thoughts only, not a CFI...

Best regards,

-a-

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aviatoreb Grand Master

aviatoreb

Posted
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7 hours ago, Raptor05121 said:

According to Mooney, 100lbs is 1.2mph

Guard: Halt! Who goes there?
King Arthur: It is I, Arthur, son of Uther Pendragon, from the castle of Camelot. King of the Britons, defeater of the Saxons, Sovereign of all England!
Guard: Pull the other one!
King Arthur: I am, and this is my trusty servant Patsy. We have ridden the length and breadth of the land in search of knights who will join me in my court at Camelot. I must speak with your lord and master.
Guard: What? Ridden on a horse?
King Arthur: Yes!
Guard: You're using coconuts!
King Arthur: What?
Guard: You've got two empty halves of coconut and you're bangin' 'em together.
King Arthur: So? We have ridden since the snows of winter covered this land, through the kingdom of Mercia, through...
Guard: Where'd you get the coconuts?
King Arthur: We found them.
Guard: Found them? In Mercia?! The coconut's tropical!
King Arthur: What do you mean?
Guard: Well, this is a temperate zone.
King Arthur: The swallow may fly south with the sun or the house martin or the plover may seek warmer climes in winter, yet these are not strangers to our land?
Guard: Are you suggesting that coconuts migrate?
King Arthur: Not at all. They could be carried.
Guard: What? A swallow carrying a coconut?
King Arthur: It could grip it by the husk!
Guard: It's not a question of where he grips it! It's a simple question of weight ratios! A five ounce bird could not carry a one pound coconut.
King Arthur: Well, it doesn't matter. Will you go and tell your master that Arthur from the Court of Camelot is here?
Guard: Listen. In order to maintain air-speed velocity, a swallow needs to beat its wings forty-three times every second, right?
King Arthur: Please!
Guard: Am I right?
King Arthur: I'm not not interested!
[A second guard approaches the parapet]
Guard 2: It could be carried by an African swallow!
Guard 1: Oh yeah. An African swallow, maybe -- but not a European swallow, that's my point.
Guard 2: Oh yeah, I agree with that.
King Arthur: [exasperated] Will you ask your master if he wants to join my court at Camelot?!
Guard 1: But, of course, African swallows are non-migratory.
Guard 2: Oh, yeah.
[Arthur begins to depart]
Guard 1: ...So they couldn't bring a coconut back anyway.
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Marauder Grand Master

Marauder

Posted
Posted
12 hours ago, Brian Scranton said:

So, I've been flying a lot lately. Maybe 75 hours in the last 3 months. Mostly with the family, dog, gear, high, hot, heavy...and I have found that my speed is consistently around 138-144KTAS in my turbo-normalized 1975 M20F (RayJay), running 24/2450, 12gph (100 ROP on the TIT) at 10,000-16,000ft with a VSI of 300-450 between 6000 and 12,000. 

Today I made a few speed mods. I left the wife, kid, dog and gear at home--and screamed up to 16,000 averaging 600-700fpm. Cruise was 148KTAS, 24/2450, 12gph ROP.

I get it. Weight makes such a huge difference. Not ready to drop carbs from my diet yet, but I am close. 

 

 

 

 

Brian -- what mods do you have on your F now? (other than the removable ones?). I know Guitarman's 1975 F has the lower cowl enclosure but not the windshield and he is averaging 147 KTAS. My 1975 F has the lower cowl enclosure, the 201 windshield and gap seals. I routinely will see 152 KTAS. 

 

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Nokomis449 Collaborator

Nokomis449

Posted
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I have the nose enclosure and a few other minor mods like gap seals and brake swap on my '68 G model.  Last week I flew the 3-legged GPS  course and input my speeds into the online computer, and it says I was getting 142 knots at 7,500 and 9,500.  I was pretty happy with that, considering I have 2,200 hours on a tired engine.

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MyNameIsNobody Grand Master

MyNameIsNobody

Posted
Posted
3 hours ago, Hyett6420 said:

If you dont want to drop the carbs, do high diving, like Tom Daley etc.  Trust me 4 hours of that a week and you tone and lose weight FAST!  

Obviously dont forget that the reason we get fat is that our mouth holes are bigger than our a holes. (As told to me by the regimental sergeant major of the Royal Artillary Company). 

Based on self observation and others input I am quite sure lower portal wins with me in the larger department...

:)

 

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Hank Grand Master

Hank

Posted
Posted
1 hour ago, Cooperd0g said:

How are you guys calculating your true air speed?

I've been using one of the back pages in my G430W. If the winds are decent this weekend, I'll do a GPS speed check coming back from the IMC club meeting and see how the two compare.

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Browncbr1 Grand Master

Browncbr1

Posted
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On 9/7/2017 at 1:32 AM, carusoam said:

Keep in mind.,.

Weight in the front seat is going to be more drag than weight in the back seat.

Drag is induced a couple of ways...

1) Adding weight at the center of lift will cause the need for an increased AOA to generate the added lift required to maintain level flight. The increased AOA will generate more drag....

2) Adding the same weight in the front seat not only increases the AOA but the tail plane has to be trimmed to pull more downforce to counteract the balance challenge...  weight + extra downforce = even larger change of AOA.....

Or so I was told....

PP thoughts only, not a CFI...

Best regards,

-a-

I always thought this as well and so, I always loaded with a little weight aft accordingly.   I noticed that the elevator has slight down deflection when trimmed for cruise with mid cg range loading.  So, today, I flew solo and noticed the same thing.  Empty plane, solo, cruise trim has down deflection.  This doesn't seem right.  

What about everyone else?

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Guitarmaster Veteran

Guitarmaster

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Posted
Weigh everything and do the math. How much did the CG actually change?
Easy inflight test:  stabilize and trim, record airspeed. Slide seat all the way back, does trim change, and record new speed. 
I gain 2-3 knots sliding my seat back.

Sent from my XT1585 using Tapatalk

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Shiny moose Proficient

Shiny moose

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In my 67F with 201 windshield, brakes rotated, lower cowl, I see 152kts true at 65% power 9500 ft density alt around 11500, burning 9.4 gal per hour. I use my trusty E6B during cruise. I have verified that it is correct with a 3 way GS calc before
I would think your TN would give you a bit better performance at altitude


Sent from my iPad using Tapatalk

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