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Greater than 2000 fpm climb!

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I'm posting this in multiple places to see where the discussion may wind.


I've asked Keith Spreuer for permission to share his setup and performance data with the web forums, and Keith was kind enough to let me do this.


Anyway, Keith recently flew his long-in-progress Subaru-powered Cozy Mk. IV with an IVO Magnum prop, and got some startling performance. For some context, Keith found out that his engine had slipped timing before he acquired it ten years ago, and in the last three weeks, he was able to diagnose this problem and get flying. From Keith's e-mail to Marc's list:


I got it running Saturday and checked the static RPM with the IVO at it's flattest pitch. Three weeks ago it was 4000 RPM now it is 4500 RPM. There is so much thrust I can not hold it with the brakes! The nose dips down like it never did before. So the RPM increase is only due to the timing improvement. The 4500 PRM is about 900 more than I've seen on any of the other props. So I made 3 taxi runs to 75 kts (rotation speed) and stopped to inspect. All was looking good so I flew it. The acceleration to 75 kias was phenomenal at less than 1000 ft of runway. As I accelerated, the RPM increased to about 5300 at lift off so I pulled the nose up to hold 90 kts and keep from going over 5400 RPM (my personal limit and peak HP). The rate of climb was over 2000 fpm!. I did a few other flights and inspected between each. There is not an issue any more with acceleration or rate of climb. I increased the pitch in cruse. The IVO performed very nicely in manual mode. This weekend was very warm here in SoCAL. It was 82 deg at 4500ft. I could not exceed 18" MAP (that's only about 55% pwr) without hitting my coolant temp limit. So I could not test the high speed end too much. It appears that I have plenty of pitch control to not over speed at the high speed end but don't have good data there yet. Now I need to work the cooling system some more.

Keith's site is here.


-- Len

-- Len Evansic, Cozy Mk. IV Plans #1283

Do you need a Flightline Chair, or other embroidered aviation accessory?

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That's a great success story. From Keith's Web site:


Engine: Subaru EG33/Ross PSRU:

I pretty much blutantly copied Phil Johnsons installation but he was able to save more weight than me in several areas. I choose this engine primarily for reliablility, secondly for cost and third for power and efficiency. Having flown airplanes powered by Lycomings for 40 years, I am not impressed with their reliability compared to cars. I can't see spending over $18K for a IO-360 and ending up with less power and less efficiency. I have total of about $10K in my Subaru including everything firewall aft. It will put out 230 hp stock. I don't plan on using that much HP but I can go to WOT at 8000 feet (either for T/O or cruise) and get 172 HP where the O-360 would only put out 135 HP. This will give me better takeoff performance and cruise speed. The specific fuel consumption is expected to be about .45 lb/hp/hr compared to about .55 for a O-360. That's about 18% better fuel economy. Of course this is all pie in the sky at this point since I've barely strated flying.

Phil Johnson's Web site is here: http://www.canardzone.com/members/PhillipJohnson


They're both interesting in that they've chosen different engines than those being packaged by http://www.eggenfellneraircraft.com (can't seem to find prices on their Web anymore, but recall ~$35K).


Power! I hope it's safe. Will be interesting to see how Phil's performs.

Jon Matcho :busy:
Builder & Canard Zone Admin
Now:  Rebuilding Quickie Tri-Q200 N479E
Next:  Resume building a Cozy Mark IV

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I think one of the comments I read was that most of Keith's increased performance may have come from getting the engine timing right. Picking up 500 RPMs at the top, is a significant amount of HP.

Nathan Gifford

Tickfaw, LA USA

Cozy Mk IV Plans Set 1330

Better still --> Now at CH 9

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