Invitation - Power, Drag, Speed (before) Your New Prop / GFC "predictions"

[Howard Handelman]

Posted By:
Please see very nice article in CAFE blog. http://blog.cafefoundation.org/




Last year my presentation did not draw a big crowd, but I hope those that came enjoyed it and learned a bit. I picked up some helpful ideas from the audience. This year expands on last year's presentation and concentrates on three areas:
1. Using the "triangle tool" to match your airplane to your new prop. Get it right before you carve or buy.
2. Using the "triangle tool" to understand (and truth-test) and even predict how some Green Flight Challenge entrants will do.

3. Looking at how we estimate BHP for a given speed and altitude. The better we do this, the better we can match that prop.
The tool is a big improvement in user-friendliness from the prior spreadsheet. The tool, in its present form, can be found on this web page: http://home.cogeco.ca/~n17hh/Models/models.html It is the first bullet in the left hand box. Last year's presentation is at the top of the page. I hope to do live demo's of some airplanes, using the tool.

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7/29/2011 - 10:00 AM - 11:15 AM - Homebuilders Hangar Aircraft Spruce & Specialty - Map
Power, Drag, Speed and Propeller Design - Last year's talk was about how to find your airplane's drag curve. This year's will review, then provide tools to estimate power and match the prop to the airplane. You design your new prop to produce a specified net power or to overcome specified drag. That will be at a specified diameter, blade count, density altitude, TAS and RPM. But how do you know the BHP? How can you predict the TAS?

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I will post the PowerPoint presentation ahead of time (same page), but I'm still polishing it at this time.
I hope to see you there.

[steveinindy]

I am planning on attending. Since I am designing a new aircraft, I need to know some of this stuff a lot better than I currently do at the moment. If you have any materials besides the Powerpoint that you feel like sharing, it would be really greatly appreciated.

[Howard Handelman]

I am planning on attending. Since I am designing a new aircraft, I need to know some of this stuff a lot better than I currently do at the moment. If you have any materials besides the Powerpoint that you feel like sharing, it would be really greatly appreciated.

My stuff is better at analyzing existing planes. But, look on www.n17hh.net for lots of source material and I will post a new tool as soon as I figure it out - working on it now. I look forward to meeting you!

[steveinindy]

Thank you for the link. I will definitely check that out.

[sonex293]

I would have loved to attend the forum, but my schedule requires me to leave either Thursday or Friday morning ...... Dang it!

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Michael Crowder
Sonex N293SX

[sonex293]

Howard, How did the forum go? Due to weather, I left on Wednesday around 2pm.....just after the big rain showers ended. I feel I missed so much of the show. Oh well.

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Michael Crowder
Sonex N293SX

[Howard Handelman]

Howard, How did the forum go? Due to weather, I left on Wednesday around 2pm.....just after the big rain showers ended. I feel I missed so much of the show. Oh well.

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Michael Crowder
Sonex N293SX

The bad news is that only about a dozen people showed up. The good news is that most of them were pretty interested and asked good questions. The best news is that Jack Norris attended and (finally) said that it was good work and that he didn't get it at first. Jack is a friend, but this was extra. If anyone wants to review the presentation in its delivered form or the updated predictions, they are on the web at http://home.cogeco.ca/~n17hh/Models/GFC/ . Also, I'm available to do 1:1 over the phone for anyone who wants to.