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  #41  
Old 03-18-2016, 07:25 PM
rightrudder rightrudder is offline
 
Join Date: Mar 2014
Location: Laguna Hills, CA
Posts: 1,853
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Quote:
Originally Posted by bret View Post
Nice!...did you say 3500 FPM climb? that's impressive! now then, back to sanding my cowl......;-(
I wish!! But even 1500 fpm seems like a pretty wild elevator ride compared to the stuff I've rented. I couldn't believe how far I was above the desert floor after just a minute or so.

Sanding sucks....I hope you're done with it soon. The results of a good job make it worthwhile.

Today I determined some cruising speeds at various rpm, done at 6500' MSL. Done without the upper nose gear intersection fairing in place, so it might be a knot faster in full slippery mode:

2500 rpm.........143 KTAS
2600 rpm.........151 KTAS
2700 rpm..........157 KTAS

I think the sweet spot for a decent cruise speed and low noise is right around 2450, where it's doing right around 140 KTAS. My goal on a long trip was to reach a cruising ground speed of 160 mph, about twice what you can (semi-legally) do in a car, and the RV-9A achieves that perfectly.

Only 15.3 gal. burned over 2.8 hours on the Hobbs, so 5.5 gph! This does include some taxiing for a landing at Apple Valley, and from Cable's fuel station back to my hangar. And a leisurely throttled-back float from 8500 ft down the pass to the flatlands.
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Doug
RV-9A "slider"--sold in July 2021
Flew to Osh in 2017, 2018 & 2019!
Donation made for 2021
You haven't seen a tree until you've seen its shadow from the sky -- Amelia Earhart

Last edited by rightrudder : 03-18-2016 at 07:38 PM.
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  #42  
Old 03-24-2016, 05:48 PM
rightrudder rightrudder is offline
 
Join Date: Mar 2014
Location: Laguna Hills, CA
Posts: 1,853
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Getting there.... 27.4 on the Hobbs now. Today's flight was the longest yet at 2.9 hrs.

I redid the right inlet ramp to reduce CHTs for Nos. 1 & 3, shortening it by about 1.5 in. I cut it where it mates to the intake with a Dremel cut-off wheel, sanded down the dry micro with a mini die-grinder sander, then used the remaining shelf to anchor the shortened ramp.

Aft end was secured with a thick bead of flox, then a couple layers of 9 oz. cloth. I sanded down the remnants of the original attachment flush with the die grinder.

The temp variance wasn't all that bad to begin with, but the change seemed to help...all cylinders are now with 10 degrees or so in cruise. But No. 1 still gets the hottest in climb, so I'll have to either remove its air dam altogether, or cut it down by half again.

I'm getting lots of practice with leaning, as I buzz the practice area in one direction, pull a U-eee, richen, climb 1000 ft, lean, buzz the other direction, descend 1000 ft, richen, and so forth.

Did a couple of landings at Apple Valley, and the aircraft is really starting to fit like a glove. After running 'er hard, it's kinda peaceful to throttle way back and just putt-putt around the pattern.

One last thought....it's the little things that make it more fun to work on our planes. A long, skinny funnel I bought from HF slips right down the dipstick tube and stays put. Best $3.99 I've spent lately.







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Doug
RV-9A "slider"--sold in July 2021
Flew to Osh in 2017, 2018 & 2019!
Donation made for 2021
You haven't seen a tree until you've seen its shadow from the sky -- Amelia Earhart

Last edited by rightrudder : 03-24-2016 at 05:53 PM.
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  #43  
Old 03-24-2016, 07:30 PM
alpinelakespilot2000 alpinelakespilot2000 is offline
 
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Posts: 3,728
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Doug,

Did u just cut down the inlet portion of the ramp or did you completely remove it and trim both ends? Wondering if how yours looks now is the way DanH suggests.

Can you get a fist in both sides now? Is that about what you were going for? Any more ideas about how much it may have dropped the temps of 1&3 relative to the others?

I'm considering doing the same to mine.
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Ellensburg WA
RV-9 Flying, 0-320, Catto

Donation reminder: Jan. 2022
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  #44  
Old 03-24-2016, 08:07 PM
rightrudder rightrudder is offline
 
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Location: Laguna Hills, CA
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Hey Steve,

I removed it and trimmed both ends. And yes, I can get a fist in both sides, as the spacing from the cylinder heads to the inlet ramps is now approximately equal.

I'd say that the temps of 1 & 3 in cruise have dropped about 10 degrees, so not a huge change but worth doing. I'll pay closer attention on the next flight and write them down on the knee board.

In addition to the higher climb CHT of the No. 1 cylinder, No. 1's EGT is also the highest. I've heard that you can adjust fuel flow to individual cylinders, so maybe if cutting the air dam down doesn't do the trick, I'll seek the services of a professional to richen up No. 1 a little.
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Doug
RV-9A "slider"--sold in July 2021
Flew to Osh in 2017, 2018 & 2019!
Donation made for 2021
You haven't seen a tree until you've seen its shadow from the sky -- Amelia Earhart

Last edited by rightrudder : 03-24-2016 at 08:17 PM.
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  #45  
Old 03-24-2016, 08:16 PM
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Vlad Vlad is offline
 
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Location: Utah
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Quote:
Originally Posted by rightrudder View Post
Getting there.... 27.4 on the Hobbs now. Today's flight was the longest yet at 2.9 hrs.




. A long, skinny funnel I bought from HF slips right down the dipstick tube and stays put. Best $3.99 I've spent lately.




If you are ever stranded faraway and need to pour a quart in, a plastic bottle with bottom cut will work the same way. Good job on flight tests Doug!
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  #46  
Old 03-24-2016, 09:10 PM
rightrudder rightrudder is offline
 
Join Date: Mar 2014
Location: Laguna Hills, CA
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Thanks for the tip, Vlad (aka McGuyver!)

I'm probably waaaaayyy overthinking the CHT issue. Nothing is absurdly out of range, oil temp is totally under control, and I was able to do a glorious full throttle 1200-fpm climb from takeoff (3092' field elevation) to 8500' this morning, with No. 1 getting up to 410 degrees.

Yet, 400 degrees would be better.
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Doug
RV-9A "slider"--sold in July 2021
Flew to Osh in 2017, 2018 & 2019!
Donation made for 2021
You haven't seen a tree until you've seen its shadow from the sky -- Amelia Earhart
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  #47  
Old 03-24-2016, 10:41 PM
alpinelakespilot2000 alpinelakespilot2000 is offline
 
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Quote:
Originally Posted by rightrudder View Post
Yet, 400 degrees would be better.
Thanks Doug.

What are your OATs down there this time of year? I've been aiming for getting temps in cruise climb to stay below 400F on days where OATs are 90F or less. Not quite there yet, but gradually getting closer.

If your injected then, yes, you should be able to enrich one cylinder at a time. Dealing with temps as I have I've regretted not having that option with my O320. Oh well, next plane!
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Ellensburg WA
RV-9 Flying, 0-320, Catto

Donation reminder: Jan. 2022
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  #48  
Old 03-25-2016, 08:51 AM
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JonJay JonJay is offline
 
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Location: Battleground
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Have a look at where your baffling sits on the ramps. On mine, there was a direct path for the plenum air to go under the ramps and squirt out the other side. I closed off the inside of the ramp which now prevents this from happening.
Your baffles may hit the ramp just right and make that seal but it is worth checking.
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  #49  
Old 03-25-2016, 04:08 PM
rightrudder rightrudder is offline
 
Join Date: Mar 2014
Location: Laguna Hills, CA
Posts: 1,853
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Thanks, JonJay. I think I'm pretty good on the sealing, judging from feeling around in there, and the wear patterns that are starting to emerge from contact.

alp2000, the OATs are varying from about 80-82 F at takeoff from 1440' (yes, we're having a warm spring!) to as low as 45 F at 8500' in the practice area. On the hotter days, I can do a shallow cruise climb (say, 120 KIAS) and have a couple of cylinders just nudge above 400 F.

It'll be telling when summer rolls around to see how that affects temps. When I'm flying around in the LA/Orange County basin after Phase 1, I won't have to push it nearly as hard as I do now, flying up to my practice area. As it stands, it's a continuous climb from my home field to 8500' at the start of every flight, in an attempt to get above the turbulence caused by the mountain pass.

Right now, I'm having more of an issue with EGT variance. I'll post a question over in "engines" to get more eyeballs on it.
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Doug
RV-9A "slider"--sold in July 2021
Flew to Osh in 2017, 2018 & 2019!
Donation made for 2021
You haven't seen a tree until you've seen its shadow from the sky -- Amelia Earhart

Last edited by rightrudder : 03-25-2016 at 04:15 PM.
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  #50  
Old 03-25-2016, 05:00 PM
jfogarty jfogarty is offline
 
Join Date: Sep 2005
Posts: 121
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Thanks for sharing, what are you seeing on your EGT? I have number 1 just above 1501, and 2,3,4 below 1470. Outside air temp 34 F. MN flying. Do you think you are getting a reduction by cutting the dam back on the lower cowling?
Also, what is your oil temp running at? Thanks.
Jim Fogarty
RV-9A Flying
Dues paid 2016
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