Precious Metal - Page 9 - RC Groups
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Jan 02, 2013, 02:08 PM
Registered User
perttime's Avatar
Just saw this thread... It reminds me of a couple of things:

Tim Hooper's Blackburn B2 that he covered with aluminium builders tape (no hot irons)
http://www.modelflying.co.uk/forums/...s.asp?th=56199
(I don't think he did a build thread here)

Macchi 72 that has the forward prop of the contraprop freewheeling:
https://www.rcgroups.com/forums/show....php?t=1792749
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Jan 02, 2013, 04:23 PM
Gravity sucks.
mrittinger's Avatar
I've used foil tape on quite a few birds. It repilcates bare aluminum well. On this bird, it has a highly polished, mirror finish, so no go
Saw the thread on the macchi, post a nasa link in there that shows the facts regarding freewheeling props.

Mark
Jan 02, 2013, 05:00 PM
Mike Brinker
tr6world's Avatar
Fantastic job Mark. Sunglasses required to fly that bird!
Jan 02, 2013, 06:54 PM
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mrittinger's Avatar
Thanks, you'll be throwing it so.... lol

Score! Got the font for the lettering and numbers from none other than Thom Richard!
That will make things a LOT easier
Jan 03, 2013, 07:53 PM
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mrittinger's Avatar
Well it took an hour of fanagling to get the font from a PC into my ancient Mac Power PC G3, but I FINALLY got it to open and work, and it's going to make things really easy! I ahve a customer with a sign shop that said he can produce the lettering on his vinyl machine..a lot easier than cutting Monokote trim sheet!
Mark
Jan 03, 2013, 10:21 PM
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mrittinger's Avatar
A little more done
Jan 04, 2013, 08:39 AM
Veni Vidi Volavi
Brian Allen's Avatar
Mark

Looking very nice!! Really going to need your sunglasses on a sunny day when PM is all done!!

Brian Allen

Veni Vidi Volavi

I came I saw I flew
Jan 04, 2013, 09:21 AM
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mrittinger's Avatar
Thanks. I hope the yellow znd black lettering and stripes will help!
Jan 04, 2013, 10:14 AM
Mike Brinker
tr6world's Avatar
was thinking about the prop size Mark. Looking at this photo, it looks like the rear prop is smaller.... Also a nice view of how the lines are for the spinner to the fues.....
That chrome covering sure looks smooth!
Jan 04, 2013, 12:08 PM
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mrittinger's Avatar
Yes, the rear prop on PM is slightly smaller dia. Im seeing significantly higher amp draws on the rear prop, even with 2" different dia....
Jan 04, 2013, 05:12 PM
Registered User
stuntflyr's Avatar
The two photos above show the airplane with two different propellers. The older square clipped prop was much shorter and the difference between the front and rear lengths much greater. The new blades are a foot longer and have very little difference in length front and aft.
Chris...
Jan 04, 2013, 10:28 PM
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mrittinger's Avatar
There is a long discussion on FB fan page aboutt he props, and Thom has been on there a good bit.
Picking up 64 mph from last years speed has been mostly due to prop change. The largest difference is the sweept blades. Apparently it has something to do with high sub-mach numbers on the prop tips.
I found a NASA test paper that said, pretty much other than noise, there's not much of an efficiency reason to have a smaller dia second prop.
What I have found in testing is that even with a 12" front and 10" rear, the rear still pulls 5+ more amps.The paper also states a 1.1 to 5% increase in rear prop pitch to be optimal, so what I really need is a 12-8LH front, and a 10-8.5 rear ....wierd, I know!

I'll play around more with props

Mark
Jan 04, 2013, 10:39 PM
Gravity sucks.
mrittinger's Avatar
Incidently, PM has 2,387,200 watts on 9000 lbs, or 265.44 watts/lb
I hope to have about 700 watts on 4 lbs, or about 175 watts/lb

Jan 06, 2013, 12:15 AM
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mrittinger's Avatar
And a couple more hours on the sealing iron....
Jan 06, 2013, 08:14 AM
Wanted for breaking Ohm's Law
Dennis Sumner's Avatar
Looks great Mark.
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