Sabremech Cowling Mod Testing (Ongoing)

[carusoam]

Reminder for @Bob_Belville to check on that external cooling substance.... described above...  ^^^^

-a-

[Bob_Belville]

@carusoam, @Marauder, @jetdriven... thanks for the comments on oil leaks and fuel line. The pic I grabbed to show Chis where my EGTs were mounted happened to be from 10/2013. The engine has been off the plane twice since and the valve cover and other oil leaks addressed more than once. 

Here's a pic from 1/18.

[Guitarmaster]

[mention=9886]Marauder[/mention],[mention=7108]Bob_Belville,@Sabremech

 

Coming home tonight at 2700ft

 

148IAS.

 

100 ROP

 

Sent from my XT1585 using Tapatalk

 

 

 

 

 

 

 

 

[Bob_Belville]

8 hours ago, Guitarmaster said:

[mention=9886]Marauder[/mention],[mention=7108]Bob_Belville,@Sabremech

 

Coming home tonight at 2700ft

 

148IAS.

 

100 ROP

 

Matt, I think that's 151 tas at 81% HP.  I suppose your temps had stabilized... is that typical of what you're seeing with your SabreCowl?    

[cnoe]

Nice observation on the EGT placement...
High MAP and ROP, the flames will be pretty far down the exhaust tube continuously converting fuel to heat and exhaust getting hotter the whole way...
Balancing the getting hotter the whole way, the exhaust gasses will be expanding rapidly, providing adiabatic cooling...
To Make raw EGT number comparisons useable between engines would require standardizing the exact location of the EGT probes.  
In this case, Each mm counts.
The one place where raw EGT gets used is measuring the turbine inlet temp TIT.  This raw EGT data is in a standardized location.
More challenges for understanding comes with TIT...

• The TIT is further down the exhaust system.
• often reads higher than individual EGTs further up.
• Conversion of fuel is most complete further down.
• combined flow from multiple exhaust streams.
• EGT is an average over time.
• hot exhaust gasses come in waves, as the exhaust valve opens.
• A turbo keeps the exhaust pressure from dropping quickly.  Minimizing the adiabatic cooling effect.

The importance of the raw number here...  protecting the exhaust parts in contact with the waves of very high temps.  
Protecting the tubes and turbine blades from erosion....
For the NA engine... EGTs relative to peak tell 99% of the story in flight.
Other Questions.... what’s causing the stain running down Bob’s #4(?) exhaust tube?
PP thoughts only,
-a-

It’s of no importance but minor interest that JPI recommends placing EGT probes 2”-4” from the exhaust ports, EI suggests 1.5”, and Insight says 2”-3”. I vaguely recall installing mine at 2.5” or 2.75” and my hottest cylinder peaks at ~1,510 F.


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[Bob_Belville]

26 minutes ago, cnoe said:

 

It’s of no importance but minor interest that JPI recommends placing EGT probes 2”-4” from the exhaust ports, EI suggests 1.5”, and Insight says 2”-3”. I vaguely recall installing mine at 2.5” or 2.75” and my hottest cylinder peaks at ~1,510 F.


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My memory sure is suspect. I thought I remembered that probe was supposed to be 6" from flange but 2-4" is what the 930 manual recommends. (I guess we drilled the PFS headers to match what we had before the EDM... 

Thanks.

[Oscar Avalle]

On 3/10/2018 at 10:05 AM, Bob_Belville said:

With my old (ARI) cowl 1&3 CHTs were 30+ hotter than 2&4. Yesterday's flight had great CHTs for 2&4 with #1 much cooler and 3 much hotter. (Overall was fine - e.g. 255/310/346/307.) I'm headed to the airport now hopeful that the 2" deflector will warm #1 and cool #3. Pirep to follow.

I would love to have those CHTs....

[mike_elliott]

16 minutes ago, Oscar Avalle said:

I would love to have those CHTs....

and with David's cowl mod and new baffles, you probably can!

[Raptor05121]

On ‎3‎/‎10‎/‎2018 at 1:03 PM, Bob_Belville said:

 

Another short, 1 hour, test flight. The 2" tape on cyl 1 worked very well. E.g. at 65% power, LOP, 5000' Cowl flaps closed: CHTs 345/321/348/328. And @ 79% power CHTs were 351/334/365/331. (OAT much warmer than yesterday +4C at 5000'). I believe this is quite a bit lower than "before" for my E and quite acceptable. 

Oil Temp peaked at 220F in BTTW, high power climb and settled down to 200F in cruise.  This is similar to "before" and I'd like to improve but if not it too is acceptable. (50W straight oil and I took off with 5.75 qts indicated. I suppose lighter weight and more oil would lower temps a little.)

Speed... I don't think I can say much. I had alt hld on the autopilot and I'm flying on the lee side of the highest ridge of mountains east of the Rockies. Next time I'll trim level and let the altitude do its thing. But my gut is I won't see 6-8 ktas improvement. 

Short clip is while level at 5000', 65% power, LOP. (Turning the phone for wide angle in the middle of the scan did not work out very well!)

 

VID_20180310_112623405[1].mp4

Any update on the speed?

[Marauder]

1 hour ago, Bob_Belville said:

My memory sure is suspect. I thought I remembered that probe was supposed to be 6" from flange but 2-4" is what the 930 manual recommends. (I guess we drilled the PFS headers to match what we had before the EDM... 

Thanks.

Yeah it is 2 to 4". 

 

[Marauder]

11 hours ago, Guitarmaster said:

[mention=9886]Marauder[/mention],[mention=7108]Bob_Belville,@Sabremech

 

Coming home tonight at 2700ft

 

148IAS.

 

100 ROP

 

Sent from my XT1585 using Tapatalk

 

 

 

 

 

 

 

 

When I get a chance I will see if I can duplicate this. I think based on my experience flying that low, your temps are really high for the OAT and power/mixture setting.

[Browncbr1]

dang maurauder, your chts are as close together as can be... 

I flew a short hop today and with aluminum tape on #1 and found that it does seem to help a little bit, but it's still the coolest.  Perhaps it will have more effect up high in thinner air.. I was only at 3000 and OAT was 35.

 

[MB65E]

On 3/12/2018 at 12:00 PM, Bob_Belville said:

@carusoam, @Marauder, @jetdriven... thanks for the comments on oil leaks and fuel line. The pic I grabbed to show Chis where my EGTs were mounted happened to be from 10/2013. The engine has been off the plane twice since and the valve cover and other oil leaks addressed more than once. 

Here's a pic from 1/18.

Bob, it looks like you have cork gaskets on your valve covers. If you are still having leaks. I’ve had good luck with silicone gaskets on the angle valve engines. 

Matt- how close are your EGT probes? sorry if I missed it during your posts. That’s pretty warm even though it’s an arbartary number anyway. 

-Matt

[MyNameIsNobody]

4 hours ago, Marauder said:

When I get a chance I will see if I can duplicate this. I think based on my experience flying that low, your temps are really high for the OAT and power/mixture setting.

Totally agree.  I never see CHT’s that high.  Even in summer.

[Sabremech]

13 minutes ago, MyNameIsNobody said:

Totally agree.  I never see CHT’s that high.  Even in summer.

We’re working to bring the CHT’s down a bit. The data we’ve received from some people with the LoPresti cowling show we’re close to what they see with that cowling installation. Matt’s also talked with some RV owners and they see very similar temps. I don’t think we’re off by much, but working to improve it and see what makes the biggest difference in cooling. I was surprised to see Bob’s temps go down when essentially his and Matt’s are identical mods except for the plates in front of the cylinders. 

David

[Bob_Belville]

Okay, @Sabremech, @Marauder, @Guitarmaster... and interested fans of Wisconsin innovation, I just returned from the airport. I used aluminum tape to simulate the VAN deflectors in front of cyls 1&3 and to simulate the baffle used on Js to cover the back 1/3 of cyl 4. I did this 3 heading speed check: http://www.eaa62.org/technotes/speed.htm @ 7500' OAT -6C, 23.3", 2550 RPM, 75% HP. TAS 160. (Worksheet calculated to 159.96, wind 286 @ 32.60.)

I was in the middle of the yellow arc on the ASI and is was bumpy so I did not try to set up 75% at 5500'.

CHTs: 342, 334, 339, 315. at 75% HP, 11.5 gph.   

I am one happy camper. 

Oh, oil temp peaked at 214 in the climb and settled at 202 with cowl flaps closed. That's a measurable improvement.

[Bob_Belville]

5 hours ago, Marauder said:

Yeah it is 2 to 4". 

 

I was going on memory, bad idea, turns out my EGT probes are 5" from flange.

[Sabremech]

28 minutes ago, Bob_Belville said:

Okay, @Sabremech, @Marauder, @Guitarmaster... and interested fans of Wisconsin innovation, I just returned from the airport. I used aluminum tape to simulate the VAN deflectors in front of cyls 1&3 and to simulate the baffle used on Js to cover the back 1/3 of cyl 4. I did this 3 heading speed check: http://www.eaa62.org/technotes/speed.htm @ 7500' OAT -6C, 23.3", 2550 RPM, 75% HP. TAS 160. (Worksheet calculated to 159.96, wind 286 @ 32.60.)

I was in the middle of the yellow arc on the ASI and is was bumpy so I did not try to set up 75% at 5500'.

CHTs: 342, 334, 339, 315. at 75% HP, 11.5 gph.   

I am one happy camper. 

Oh, oil temp peaked at 214 in the climb and settled at 202 with cowl flaps closed. That's a measurable improvement.

Hi Bob,

What kind of speed did you gain? I forgot what your pre-mod number were.

Thanks,

David

[Bob_Belville]

Just now, Sabremech said:

Hi Bob,

What kind of speed did you gain? I forgot what your pre-mod number were.

Thanks,

David

David, I suppose upwards of 5 ktas. I seldom ever cruise at 75%, RoP but I think it would have been 155 or a little more. Today was pretty bumpy over our mountains so the margin of error of the speeds I logged was at least +/- 2 kts. Hopefully we'll get some better conditions to see more stabilized speeds this week before I take it to paint Monday.  

[Bob_Belville]

On 3/11/2018 at 8:11 PM, Marauder said:

 

Ok, here are my numbers from today:

Flew 7500 @ 70%, leaned to 80° ROP, FF 11.0, MP 21.7, RPM 2540, 152 KTAS

 

 

 

 

 

 

 

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Chris, was that full throttle? Your MAP at 7500' is 21.8. I just noticed that today mine was 23.3 at 7500. OAT may be part of it and PFS should help as well as my new Sabrecowl intake.

Since all our old air frames differ in many ways that affect drag/speed, perhaps BTTW MAP should be compared carefully to judge what improvement can be expected.  

Our EDMs have a MAP adjustment feature, not sure about our Aspens.

[Marauder]

56 minutes ago, Sabremech said:

We’re working to bring the CHT’s down a bit. The data we’ve received from some people with the LoPresti cowling show we’re close to what they see with that cowling installation. Matt’s also talked with some RV owners and they see very similar temps. I don’t think we’re off by much, but working to improve it and see what makes the biggest difference in cooling. I was surprised to see Bob’s temps go down when essentially his and Matt’s are identical mods except for the plates in front of the cylinders. 

David

I don't believe based on your earlier post that you have the Van's baffles installed yet on Matt's. Be curious what his temps will look like once afterwards. Based on my 27 years experience with the IO-360 in an F, he is running ~40 degrees hotter than I would expect based on the conditions. My obvious concern is what will happen when summer temps hit us. I went through all of my old photos and found all warmer weather temps were no higher than 340 for the hottest temps. If he can get into the 360 range on a hot summer flight, that will work. He will need to be more attentive during the climb if he wants to stay below 390 degrees.

You got the right guy for this testing. Anyone who would smear his plane with engine oil as a poor man's wind tunnel is serious about his testing.

[Marauder]

3 minutes ago, Bob_Belville said:

Chris, was that full throttle? Your MAP at 7500' is 21.8. I just noticed that today mine was 23.3 at 7500. OAT may be part of it and PFS should help as well as my new Sabrecowl intake.

Since all our old air frames differ in many ways that affect drag/speed, perhaps BTTW MAP should be compared carefully to judge what improvement can be expected.  

Our EDMs have a MAP adjustment feature, not sure about our Aspens.

Bob -- everything I do is at full throttle  I will take whatever MP I can get and adjust RPM to get to the percent power setting I want. We may be seeing a difference due to the efficiency of the Van's intake. One way to know for sure is to open my ram air at 7500' and see what I get. I went through my old photos and found another 7500' flight. I always run 80 degree ROP. 

The difference however could be due to different pressure. What was your barometric pressure on today's flight? The flight below was at 29.92", the one above was at 30.07". Could account for some of the difference?

[N6758N]

15 minutes ago, Marauder said:

I don't believe based on your earlier post that you have the Van's baffles installed yet on Matt's. Be curious what his temps will look like once afterwards. Based on my 27 years experience with the IO-360 in an F, he is running ~40 degrees hotter than I would expect based on the conditions. My obvious concern is what will happen when summer temps hit us. I went through all of my old photos and found all warmer weather temps were no higher than 340 for the hottest temps. If he can get into the 360 range on a hot summer flight, that will work. He will need to be more attentive during the climb if he wants to stay below 390 degrees.

You got the right guy for this testing. Anyone who would smear his plane with engine oil as a poor man's wind tunnel is serious about his testing.

You F' guys need to come fly a C in the summer before you start complaining about CHTs...

[Marauder]

Just now, N6758N said:

You F' guys need to come fly a C in the summer before you start complaining about CHTs...

Yes indeed. We hear you C owners can quickly fry an egg.

[Sabremech]

15 minutes ago, Marauder said:

I don't believe based on your earlier post that you have the Van's baffles installed yet on Matt's. Be curious what his temps will look like once afterwards. Based on my 27 years experience with the IO-360 in an F, he is running ~40 degrees hotter than I would expect based on the conditions. My obvious concern is what will happen when summer temps hit us. I went through all of my old photos and found all warmer weather temps were no higher than 340 for the hottest temps. If he can get into the 360 range on a hot summer flight, that will work. He will need to be more attentive during the climb if he wants to stay below 390 degrees.

You got the right guy for this testing. Anyone who would smear his plane with engine oil as a poor man's wind tunnel is serious about his testing.

We don't have the Van's air dams installed in front of his cylinders. We've decided to do a little at a time to see what makes a difference. We trimmed 1/2 an inch off of the #1 cylinder air dam today. We also worked on the baffle seals a bit. After Matt completes his annual, he'll fly it and see what progress we made. After that we'll remove the # 1 and 2 barrel air dams and test again. I'm glad Matt is as patient as he is about testing. I'm making small changes so we can see what really has an effect. 

Thanks,

David