Sabremech Cowling Mod Testing (Ongoing)

[Browncbr1]

13 hours ago, Guitarmaster said:

Riley and I went flying yesterday with the new induction system and the louvered bottom panel.

The induction system is great!  There is very little restriction now.  I am seeing only 0.6 - 0.7 inHg difference between ambient pressure and WOT on take-off.  Previous, I was seeing a delta around 1.2 inHg on take-off.  I think that is about as perfect as it gets for a NA airplane.  At altitude, the MP seems to be ~ 0.5 inHg different (lower) than my previous flights with RamAir open.  The conclusion is, with the new intake, the RamAir would create a negligible difference; at best, maybe 0.5 inHg difference.  That makes it unnecessary in my book.  With the removal of the RamAir, came a very clean installation under the hood (I will have pictures later) and it cleaned up the front nicely (see attached pic).
 A side-effect of the intake is that my engine idles very smoothly!  Before, it would run like a big-block Chevy at idle when warm.  That problem is long gone!  The fact that the induction boot was ripped probably had something to do with that.  Regardless, the engine loves the smooth intake air.
As those that have followed this thread for a while know, we are seeing increased CHT's with the removal of the third cowl flap.  We really wanted to keep it gone because it makes such a clean installation.  Unfortunately,  the latest test data indicates a simple louvered panel is not going to cut it.  David will be reinstalling the third cowl flap shortly and we will have results after that.
So the tweeking (not twerking) continues......  
 

 

that middle panel that is louvered is not open at all on my 67F.   Mine is completely closed.   I’ve not had CHT temp issues, but I have the oem guppy cowl.   Was the third cowl flap on yours a previous mod or something?

[Marauder]

 
that middle panel that is louvered is not open at all on my 67F.   Mine is completely closed.   I’ve not had CHT temp issues, but I have the oem guppy cowl.   Was the third cowl flap on yours a previous mod or something?

The third fixed cowl flap was factory original on the later F models. I had the guppy mouth as well before installing the Lasar cowl enclosure.

I wonder if the earlier F models had larger cowl flaps?


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[Bob_Belville]

The third fixed cowl flap was factory original on the later F models. I had the guppy mouth as well before installing the Lasar cowl enclosure.

I wonder if the earlier F models had larger cowl flaps?


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My E runs hotter than your late F. I suppose that's because of your extra exit air capacity. Based on Bob Kromer's data I have extended the range of the cowl flaps which should accomplish the same thing. Of course it also increases drag...

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[Browncbr1]

2 hours ago, Marauder said:

 

The third fixed cowl flap was factory original on the later F models. I had the guppy mouth as well before installing the Lasar cowl enclosure.

I wonder if the earlier F models had larger cowl flaps?


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If the 67F had larger cowl flaps, then I wouldn't understand why Mooney would have changed them to be smaller, but then have to add a third... The only thing I could think about is cowl flap speed.  Is your cowl flap speed on your 75F 150mph ?

[Marauder]

17 minutes ago, Browncbr1 said:

If the 67F had larger cowl flaps, then I wouldn't understand why Mooney would have changed them to be smaller, but then have to add a third... The only thing I could think about is cowl flap speed.  Is your cowl flap speed on your 75F 150mph ?

Cowl flap speed limitation is the same as yours. The limitation may be set due to the limitation of forces on the hardware (damage to the cowl flap extension mechanism working against higher airspeeds). The only other reason they could have went with the third fixed cowl flap was a heat related issue. My CHTs in the summer will sit in the low 300s. From 310 to 335. What are yours?

[Browncbr1]

1 minute ago, Marauder said:

Cowl flap speed limitation is the same as yours. The limitation may be set due to the limitation of forces on the hardware (damage to the cowl flap extension mechanism working against higher airspeeds). The only other reason they could have went with the third fixed cowl flap was a heat related issue. My CHTs in the summer will sit in the low 300s. From 310 to 335. What are yours?

in the summer, my hottest cylinder (#3) will be 310-320 running 65-70% at peak-15LOP (Hank's 47 method down low, or about 46 up high)..   I have collar probes on my tanis probes, which some say read about 20-30 degrees lower than bayonet cht probes.  This is with cowl flaps completely closed, but I usually have to crack them to keep oil temp in check. (oem oil cooler location)

[Marauder]

10 minutes ago, Browncbr1 said:

in the summer, my hottest cylinder (#3) will be 310-320 running 65-70% at peak-15LOP (Hank's 47 method down low, or about 46 up high)..   I have collar probes on my tanis probes, which some say read about 20-30 degrees lower than bayonet cht probes.  This is with cowl flaps completely closed, but I usually have to crack them to keep oil temp in check. (oem oil cooler location)

Interesting. If I ran at the same power settings, I would be in the same temp ranges as you. I run ROP and typically at 80 to 100 degrees ROP. I am using a JPI 900 with CHT probes (I have Reiff band heaters on the cylinder bases). I never need to open the cowl flaps to cool the oil. My typical oil temps are in the 180 to 195 range (typically closer to the lower end). 

[Hank]

59 minutes ago, Browncbr1 said:

in the summer, my hottest cylinder (#3) will be 310-320 running 65-70% at peak-15LOP (Hank's 47 method down low, or about 46 up high)..   I have collar probes on my tanis probes, which some say read about 20-30 degrees lower than bayonet cht probes.  This is with cowl flaps completely closed, but I usually have to crack them to keep oil temp in check. (oem oil cooler location)

I'm glad to see that some people value my advice . . . But the Key Number = 47 is for the O-360 in my C; it's a higher number for your F, I'll have to dig out my MAPA PPP notebook to look it up. I generally fly at 46 myself.

[Browncbr1]

26 minutes ago, Hank said:

I'm glad to see that some people value my advice . . . But the Key Number = 47 is for the O-360 in my C; it's a higher number for your F, I'll have to dig out my MAPA PPP notebook to look it up. I generally fly at 46 myself.

Yea, I always run 46 locally or 47 enroute.  Any higher and I run rich

[Aviationinfo]

5 hours ago, Browncbr1 said:

Yea, I always run 46 locally or 47 enroute.  Any higher and I run rich

Pls explain this method?  Thx.

[Guest]

33 minutes ago, Aviationinfo said:

Pls explain this method?  Thx.

I think that’s RPM plus MAP.

Clarence

[Browncbr1]

54 minutes ago, Aviationinfo said:

Pls explain this method?  Thx.

Rpm/1000 + MAP

[Hank]

4 minutes ago, Browncbr1 said:

Rpm/1000 + MAP

For those of us still flying steam, it's just the numbers from the tach added to MP. Keep at or below the Key Number and you will avkid the red box. For my O-360, the Key Number = 47, so at altitude, 20"/2500 is plenty fine but at 6000' where MP can be higher, I like 22"/2400 unless I'm in a hurry. 

[Aviationinfo]

Thank you!  Just recently I was looking for an easy way to avoid the red box and had resigned myself to constantly checking the POH for % power.   This is way better.    Sorry for the thread creep.

[Hank]

16 minutes ago, Aviationinfo said:

Thank you!  Just recently I was looking for an easy way to avoid the red box and had resigned myself to constantly checking the POH for % power.   This is way better.    Sorry for the thread creep.

I keep the Performance Tables on my kneeboard, but mostly use only three settings:

• Low, short hops, ~3000'     23/2300
• Medium, 4000-6500 +/-     22/2400
• Long distance, >7500        WOT-/2500

The "-" is on WOT because I pull throttle until the MP needle wiggles, to cut off the automatic enrichment circuit in my carburetor. Note that your settings will be different due to your fuel injected, 200 hp engine . . . and likely different prop restrictions. But once you get set up, these are also handy settings as ATC steps you down toward your destination. 

[Bob_Belville]

We should have our GDS (@Sabremech) cowl installation complete tomorrow! I replace the rest of the baffle seals while we were at it.

The baffling and fg duct is beautiful.

[jetdriven]

Panel, check. 

Fresh motor,  check. 

Updated cowl, check. 

Fresh paint, check..    

i think you’re done, Bob.  Nothing left to do now but sell it and buy a Bonanza..

[prflyer]

19 hours ago, Bob_Belville said:

We should have our GDS (@Sabremech) cowl installation complete tomorrow! I replace the rest of the baffle seals while we were at it.

The baffling and fg duct is beautiful.

Looking great Bob!  Question, did your 66E come out of the factory with baffles or did you convert it?  Mine is a 65 model (manufactured in December 1964) but has the doghouse.

Really looking forward to your tests with the new cowling.

Fernando

[Bob_Belville]

1 hour ago, prflyer said:

Looking great Bob!  Question, did your 66E come out of the factory with baffles or did you convert it?  Mine is a 65 model (manufactured in December 1964) but has the doghouse.

Really looking forward to your tests with the new cowling.

Fernando

I guess I don't know if the doghouse was still being used when my '66 was built. I've only had it 6 years. It got the ARI mod 20 years ago but I don't know the history of the baffling though the front has never been well sealed.

We finished putting on the cowl parts today. It was too windy to go flying and it was about 5:00 but I had to taxi around the ramp for 20 minutes and take a few pics...

I'm fired up!

 

[Sabremech]

HI Bob,

 I was concerned how it was going to fit not having the airplane in my shop, but it looks great from the pictures. I received your last e-mail and will touch base with you tomorrow. Looking forward to yours and Lynn's impression of my mod.

David

[Bob_Belville]

52 minutes ago, Sabremech said:

HI Bob,

 I was concerned how it was going to fit not having the airplane in my shop, but it looks great from the pictures. I received your last e-mail and will touch base with you tomorrow. Looking forward to yours and Lynn's impression of my mod.

David

We were both amazed it how well it fit, particularly around the spinner. We did have to remove 2 tabs/flanges on the new starter but as I mentioned in my email everything went very smoothly.

I wish we'd done a dental type impression before I redid the old seals around the baffling that you did not get. We've got a couple of folds to work out...

[Sabremech]

2 minutes ago, Bob_Belville said:

We were both amazed it how well it fit, particularly around the spinner. We did have to remove 2 tabs/flanges on the new starter but as I mentioned in my email everything went very smoothly.

I wish we'd done a dental type impression before I redid the old seals around the baffling that you did not get. We've got a couple of folds to work out...

Baffling is a pain in the butt!! 

[Bob_Belville]

1 minute ago, Sabremech said:

Baffling is a pain in the butt!! 

I've been fussing with mine for 6 years and it was still a mess.

[Browncbr1]

Bob, if you are out this way anytime, please give me a heads up..  I’d like to see it in person.  

I think I’ve worked out a bartering deal with a friend IA.. I’ll probably do the interior on his Beech35 and he will do my side windows, windshield, and cowl mods.  

[Mcstealth]

1 hour ago, Browncbr1 said:

Bob, if you are out this way anytime, please give me a heads up..  I’d like to see it in person.  

I think I’ve worked out a bartering deal with a friend IA.. I’ll probably do the interior on his Beech35 and he will do my side windows, windshield, and cowl mods.  

Not sure who gets the better end of that deal