RV9 200HP Yamaha Sidewinder

[Teal]

I would like to post pictures on my post. Can someone please tell me how to do that?

[pazmanyflyer]

Originally Posted by Teal

I would like to post pictures on my post. Can someone please tell me how to do that?

When you start your message there is a paperclip icon at the top next to a smiley face.
1. Click the icon.
2. Browse for and select the photo(s) you want to insert as the attachment(s).
3. Upload photo(s). (Repeat steps 2 and 3 for multiple photos.)
4. Close the window when you have finished uploading.
5. Click on the paperclip again to manage the attachments.
6. Choose the photo(s) you want to attach. They will be inserted into the body of your text with a [ATTACH]XXXXX[/ATTACH]. You can then add them to the end or insert them in between paragraphs, etc.
7. Hit submit reply to post.

If you want to add a link to a photo then you can use the Insert link icon (world with a link) under the smiley face. Be careful of Doug's rules when posting from a non-advertiser or outside web site. See his rules here so not to get into any trouble.

[gasman]

Originally Posted by Teal

I would like to post pictures on my post. Can someone please tell me how to do that?

Pictures must be in your computer file.
Click on this paper clip...


Click on choose a file...


Click on the picture file and click open.
Click upload. File will display....


Repeat for all pictures you want in the post.
Click on the post page location to clear the screen.
Type your message. Then place curser where you want
the picture. Click the paper clip again.


The files will show up. Pick the file you want in that spot.


The attached file will look like this.....


Now, preview your post....

[lr172]

Originally Posted by Teal

Ok, On this mornings flight I tried to duplicate some of the other RV9 cruise flight numbers.
At 8k ft and 150KTAS it was indicating 8.9GPH. at best RPM and manifold pressure which was 6300 RPM and 35.7INHg.
At 10k ft and 150KTAS it was indicating 8.5 GPH and 6300 , 35.3INHg.
Important to note that at these cruise numbers the AFR is still only 12.9-13. so there is much leaning to go in the tune at these manifold pressures. Also we are still tweaking on the fuel flow computer calcs each flight.
Perhaps of some importance is the above numbers represents about 20MPG (no winds). At the end of the last few flights I have drained the fuel and looked at total miles covered and it averages about 21MPG. That seems pretty good considering on the 1 hour flight I climbed to at least 12kft. Yes, I get some back on the glide descent but not equal.
In the end though my goal wasnt to try to get better fuel economy than the standard aircraft engine I think they do a great job of already.

With the big bore Lyc's, we are getting good fuel economy by running lean. These engines are turning low RPMs, so easy to get very lean. In the 10, I am cruising mostly at 50-75* LOP, which is probably about 17:1 or a bit less. Given you are turning higher RPMs and possibly can't get as lean, there may be better economy by running 15:1 with the higher speed. Not sure how lean you can get with 35" of MAP though. On my porsche boxer engine with turbo, I go quite lean in the tables with the closed loop mode, but it is in cruising condition at lower RPMs with no real boost involved. Never tried getting less than 12.5:1 on the 8 PSI of boost. Too scarry and not worth it for me as, unlike the plane in cruise, I don't spend great deals of time there. I would be quite cautious about anything below 13:1 when boosted. That said, I have no real experience to offer. Do you have an electronically controllable waste gate? Maybe an idea is to drop the boost way down and try lean settings at cruise. Lower RPMs with a coarser pitch may be a benefit given the limited blade area you referenced.

One thing I do know is that each combustion chamber design has different characteristics that limit AFR and advance, so be sure your tuner has experience with this engine if he is recommending AFRs lower than 13:1 on 35" of MAP. leaner AFR's can get things pretty hot at high MAPs. When speaking of pistons and rings, heat kills. Then again, many engines designed for high boost applications have pretty low dynamic compression ratios and therefore aren't producing a lot of heat at low boost levels and therefore don't need excess fuel there. Devil is in the details.

Larry

[rv6ejguy]

I'd generally agree with Larry here on leaning too far with this high specific output engine. Unless it has oil jetted, forged pistons, the heat flux into the piston crowns and upper ring land areas may make for short life when running near stoich.

Most automotive engines (also relatively high specific output) typically run in the 11 to 1 range at high power settings to keep the pistons alive.

A Lyc at 75% only has a specific output of 23hp/L. This engine would be at 135hp/L to match an O-360- almost 6 times the specific output.

[Teal]

Larry and Ross, Thank you for the advice.
The engine does have oil squirters cooling the pistons but I am not sure if they are forged.
The only comparative engine that I have data on is the fuel injected Rotax 912. I communicate often with Thomas Hauklien the owner of edge performance. They make an after market EFI and turbo system for these engines. He claims they run 1500-1550F on EGT's at cruise power settings and AFR of 14.5-14.9.
Currently I am at 1430-1450 at cruise power settings. I definitely will be proceeding with caution

[rv6ejguy]

Good stuff. Kudos for putting the "E" back in Experimental. A most interesting project.

We're all hoping it lasts well and could pave the way for a few more wishing for something different up front.

[bmille32]

Teal,
I looked at this at Oshkosh and it's very impressive. I'm interested in knowing the outcome of the prop issue you experienced with the airmaster. Have you considered a four blade prop to gain the extra surface area you where referring to in previous post? How are you controlling boost. I have so many questions but I will leave them for another time. Thanks for your work paving the path less followed.

[Canadian_JOY]

A local builder put a similar, non-turbo'd Yahama on his CH701 using a belted reduction drive. Throttle response was almost silly-fast and the power output was impressive. Visually these engines appear to be of very high quality. These are amazing engines and, if we can get the bugs worked out, likely represent one of the brightest spots in "non-aviation" engine conversions.

[Dad's RV-10]

Originally Posted by Teal

Larry and Ross, Thank you for the advice.
The engine does have oil squirters cooling the pistons but I am not sure if they are forged...

According to this article, the pistons are forged.