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  #441  
Old 11-03-2019, 05:18 PM
charosenz's Avatar
charosenz charosenz is offline
 
Join Date: Aug 2009
Location: Longview, Wash
Posts: 363
Default Good results on hard run up to 40" hg MAP

After closing up all the air leaks in the intake system and calibrating the BOV and Waste gate release pressure I was able to do two hard run ups to 4400 rpm.

I am very please with the 72" 3 Bladed warp drive prop. It seerms to be a very good match for my set up. The prop had enough resistance when set at 20 degrees pitch that it held at 4400 rpm. It held at 4400 RPM at about 35 inches MAP. I increased to 40" hg, and the prop held firm at 4400 RPM static. These runs are of course on the ground.

Temps were real good as well. I started the run up at 170 degrees on the coolant and while on the ground with no radiator shroud, I can get several minutes above 30" MAP before it overheats. I can run at 25" MAP all day and it stays at 185 degrees. Very Happy with the radiator performance.

Unfortunately I regret I forgot to look at IAT. I sure wish I had looked but I was much more interested in MAP and RPM and Coolant temps. Running at that RPM in your parking lot is very nerve wracking.

After two runups, I pulled the plugs and they all looked very nice. I also did a compression test. The engine was still slightly warm . All cylinders were between 220-235 lbs. I am very happy with that.

This is really a good milestone for this project. The success it motivation to push forward.

Charlie
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  #442  
Old 11-04-2019, 12:08 PM
sblack sblack is offline
 
Join Date: Dec 2009
Location: Montreal
Posts: 1,409
Default

how can you have 2 runs at the same rpm but different MAP? This is a fixed pitch prop right? I don't know of a CS warp drive but I suppose nothing is impossible. Different MAP means different power being produced, so the RPM should be higher at the higher MAP. Something is strange here.
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Old school simple VFR RV 4, O-320, wood prop, MGL iEfis Lite
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  #443  
Old 11-04-2019, 01:26 PM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
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Default

Quote:
Originally Posted by sblack View Post
how can you have 2 runs at the same rpm but different MAP? This is a fixed pitch prop right? I don't know of a CS warp drive but I suppose nothing is impossible. Different MAP means different power being produced, so the RPM should be higher at the higher MAP. Something is strange here.
Prop blades could be partially stalled during the static run. Seen this many times on test stands so clubs are preferable.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 437.8 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi2.htm



Last edited by rv6ejguy : 11-05-2019 at 09:20 AM.
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  #444  
Old 11-04-2019, 03:21 PM
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charosenz charosenz is offline
 
Join Date: Aug 2009
Location: Longview, Wash
Posts: 363
Default Prop and MAP limitsq

Ross,

Yes, that is what I believe is happening at about 4100 RPM when the RPM no longer increases with the MAP in lockstep.

I will drop the pitch a degree or two to move up the static RPM to 4400-4500 with 5-7 lbs boost and call it good. I believe that would be ideal for this engine, PSRU and this airframe. My target max rpm in flight is 5000 RPM and cruise will be 4200-4600 rpm with about 5lbs boost.

With all the other systems.... Coolant, ECU, PSRU, etc all performing well, I plan to move on to some more mundane tasks like finishing the panel, pitot systems, control rigging, interior work etc.

Thanks.

Charlie
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  #445  
Old 11-04-2019, 08:49 PM
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charosenz charosenz is offline
 
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Location: Longview, Wash
Posts: 363
Default testing prop pitch and map and boost

I dropped the pitch to about 18.5 degrees and did a couple of short run ups.

As you would suspect I gained 300-400 RPM but the MAP was down a bit. At 4600rpm and about 36" map. This time I saw about 115*F IAT. EGT was 1200*F. PSRU was about 105*f.

I am still very happy with this set up. I believe 20* with 4100-4200 ish static RPM is a good place to start. RPM will increase some when the plane is air borne. From there, it will be time to do more testing.

I did expect (and hope) to see slightly higher MAP with this prop at that RPM and that pitch, but I am very close to those ideal numbers that I see nothing to change.

I did wonder if my turbo compressor reference line might have been pushing my waste gate actuator open a bit too early? Since I am only doing ground testing, I disconnected it to see what the system would do with no reference signal. Since the waste gate is set to move at about 9 lbs, I doubted this was happening but I just had to test it. My guess was correct. No change at all. Since the BOV is set to release at 10 lbs I am confident this is not limiting the boost as well.

The only other logic I can see would be that the turbine trim of this T3/T4 turbo is tad too large to produce boost as early as would be ideal.

But at this state I am still very happy with it and I need to move on to other tasks. One will be to build a shroud for the intercooler to take advantage of ram air once in flight.

Charlie

Last edited by charosenz : 11-04-2019 at 08:53 PM.
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  #446  
Old 11-05-2019, 05:59 AM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
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Location: Calgary, Canada
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What turbine wheel and housing are you running?

The prop won't be stalled once you're moving so you can expect quite a bit more rpm in flight. You're likely to find the FP prop won't be the best compromise in cruise flight, especially up high with the turbo since power doesn't drop off.

I have to add a lot more pitch when I level off up high, even at moderate MAP levels.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 437.8 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi2.htm



Last edited by rv6ejguy : 11-05-2019 at 09:21 AM. Reason: correction of terms used
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  #447  
Old 11-05-2019, 08:50 AM
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skylor skylor is offline
 
Join Date: Aug 2009
Location: Southern California
Posts: 792
Default Cavitation

Quote:
Originally Posted by rv6ejguy View Post
The prop won't cavitate once you're moving so you can expect quite a bit more rpm in flight.
Let's get one thing straight. Air propellers can not cavitate. EVER. Cavitation is specifically a phenomenon that occurs in liquids when localized pressures drop below the liquids' vapor pressure and gas bubbles form.

The phenomenon the you are calling "cavitation" is more likely aerodynamic stall of the blades which can occur during static run-up due to the high relative angle of attack of a propeller blade moving at high speed in still air. Forward motion of the aircraft reduces angle of attack of the propeller blades.

Skylor
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  #448  
Old 11-05-2019, 09:19 AM
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rv6ejguy rv6ejguy is offline
 
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Location: Calgary, Canada
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Default

My bad choice of terms here. You are correct.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 437.8 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi2.htm


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  #449  
Old 11-05-2019, 10:01 AM
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charosenz charosenz is offline
 
Join Date: Aug 2009
Location: Longview, Wash
Posts: 363
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Ross,

Here are the numbers for my turbo.

The Compressor is .60 A/R IN: 54.3mm EX:71mm
54.3 x 54.3 = 2950 71 x 71 = 5041
2950/5041 = 58 Trim on the compressor with a .60 A/R
Turbine is .63 A/R IN:65.25mm EX: 56mm
65.25 x 65.25 = 4257 56 x 56 = 3136
3136/4257 = 74 Trim on the Turbine with a .63 A/R


Charlie
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  #450  
Old 11-05-2019, 10:45 AM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
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Location: Calgary, Canada
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Default

All look reasonable here. I'd expect you should be able to make 40 inches at 4000 rpm easily
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 437.8 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi2.htm


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