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Old Apr 12, 2006, 03:57 PM
Who Put that Tree There?
Krashlnd's Avatar
Athens, Tennessee
Joined Jun 2003
505 Posts
Oops last question. Should I have one prop spinning the oposite direction?
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Old Apr 12, 2006, 04:25 PM
Registered User
Crossville, TN
Joined Dec 2004
2,907 Posts
It works on the P-38 , and some of the Piper twins had this feature. Cancels out the torque and the critical engine-out situation .
The problem will be in the reverse rotation prop availability.
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Old Apr 12, 2006, 05:34 PM
G G Ghost Pirates !!!
Vyceroy's Avatar
USA, NC, Gastonia
Joined Dec 2001
8,823 Posts
its not necessary .. i run my twins both in the same direction.. hard to find counter roating props
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Old Apr 12, 2006, 07:52 PM
Who Put that Tree There?
Krashlnd's Avatar
Athens, Tennessee
Joined Jun 2003
505 Posts
Vyceroy,
Give me an idea on how to tie both ecs's together to the rx.
Thanks Steve
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Old Apr 12, 2006, 08:21 PM
G G Ghost Pirates !!!
Vyceroy's Avatar
USA, NC, Gastonia
Joined Dec 2001
8,823 Posts
ok what i did was make a Y connector then pull the red pin on one of the connectors to shut the BEC off .. dont need 2 BECs .. thats how i did mine ..
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Old Apr 13, 2006, 07:01 PM
Who Put that Tree There?
Krashlnd's Avatar
Athens, Tennessee
Joined Jun 2003
505 Posts
awesome, thanks.
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Old Jun 20, 2006, 09:35 AM
Given up counting
alexeames's Avatar
Bicester, UK
Joined Sep 2005
2,372 Posts
Krashlnd,

have you finished your Puddle Twin II yet? How's it fly on BP21s? I would imagine that it has more than enough power.

I'm going to build one of these with two BP21's (more specifically two Tower Pro 2408-21's with second generation 15A controller and 2A BEC).
My motor supplier says not to use more than 7 * 6 prop with 3s and to keep the current max 12A. I suppose if it flies well on speed 400 and Gunther, then a 7 * 6 should be enough? I don't know if I will LiPo or not though.

The depron should be here soon. Looks like a lovely plane. I'm going abroad and wanted to take a plane with me. The best solution I came up with was to cut out the parts here and assemble when I get there.

Really looking forward to this build. Thanks for the plans Roland. I was originally put off by the fact that it needs two motors, but hey I suppose plenty of power for ROW shouldn't be a problem.
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Old Jun 20, 2006, 05:05 PM
Who Put that Tree There?
Krashlnd's Avatar
Athens, Tennessee
Joined Jun 2003
505 Posts
It flys great. Alot of power with the bp21s. Ill post some more pics after work.
Steve
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Old Jun 21, 2006, 02:13 AM
Given up counting
alexeames's Avatar
Bicester, UK
Joined Sep 2005
2,372 Posts
Did you go with the 8040 props? NiMH or LiPo? My depron's just arrived
How did you mount the BP21 motors?

I've cut out all the 6mm parts, just the 3mm to go. This is gonna be a bit frustrating because I want to build it straight away, but it's for a trip. So I need to make it as ready to assemble as possible without actually gluing it together.

I taped it together with scotch magic tape (which comes off really easily) just to see what it'll look like. WOW. It's much bigger than I thought. That tailplane is huge I put my Tx in the shot just to give it scale.

Couple of queries regarding the plan though as my German is very limited...

40mm washout at the wing tip?
65mm back from leading edge for centre of gravity? schwerpunkt (got that from my EasyStar manual)

I may have other questions. Please bear with me guys. This is going to be fun.
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Old Jun 23, 2006, 06:07 AM
Given up counting
alexeames's Avatar
Bicester, UK
Joined Sep 2005
2,372 Posts
Build pictures

Realised I didn't upload the pictures yesterday.

Got another question too. I can see that F20 is supposed to go at the front of the wing and with a couple of 5mm 10cm length carbon fibre rods poking through. What's that for? Is it to attach the wing to or is it to strengthen the internal structure?
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Old Jun 23, 2006, 07:22 AM
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rmerk's Avatar
Augsburg Muehlhausn, Germany
Joined Jul 2003
24 Posts
Hi,

nice to see that you buildt my Plane!

Your Questions:
- 40mm washout at the wing tip?

No washout is needed. This is the dihedral for each wing tip.

- 65mm back from leading edge for centre of gravity? schwerpunkt

Yes, "schwerpunkt" means centre of gravity.

- the carbon rod artwork

it is for attaching the wing. I have glued a piece of plywood (F20) with two holes in it to the former F3 and glued two carbon rods to the bottom of the wing. The wing is secured whith the nylon screw at the leading edge. If you prefer a other way to attach the wing please feel free to change it.

Perhaps i should translate the plans into english...

By the way: I have added airbrakes to my 1,1m Puddle Twin 2. Just to test the function on such a small plane. The landing speed is not significant lower but she is more stable if you slow her down. It is a nice gimmick

Greetings, Roland
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Old Jun 23, 2006, 07:35 AM
Given up counting
alexeames's Avatar
Bicester, UK
Joined Sep 2005
2,372 Posts
Excellent. Thank you Roland.

I saw your photo on page 3 of this thread where you were making the wing and the end was propped up. So it's actually a bit of dihedral and not washout. OK - clear now thank you

It would be really excellent to have the written bits in English actually. If you would like, I will take photos along the way which could be used in some kind of build guide. But I won't be assembling this plane until I get to Poland in a couple of weeks. We've got a house there and go there for a few weeks each summer. I fancied a waterplane as there is a large boating lake not far away from the house.

Hopefully, once it's flying I should be able to get some video as well.

I'm hoping to go with 2 BP21s and a 3s Lipo. I suppose it will have to go quite far forward to balance, but I'll cross that bridge when I get to it.

Thanks for your help Roland. Looks like a great fun plane.
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Old Jun 24, 2006, 12:07 PM
AMA 125691
wmcneal's Avatar
Jacksonville Florida
Joined Jul 2002
2,240 Posts
A friend of mine built one of these planes with two BP21s and 3s li-pos. I saw it fly for the first time today. It was awesome! It had plenty of power to take off from the grass field where we fly. At first the CG was too far back and it snap rolled on him and almost crashed, but he had enough altitude to pull out. After he landed he re-adjusted the cg forward and it flew beautifully. Also, since the tail has such a short moment compared to the wingspan it tended to drag the tail if he didn't co-ordinate some rudder in the turns. This one is definately going on my build list!
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Old Jun 24, 2006, 03:24 PM
Given up counting
alexeames's Avatar
Bicester, UK
Joined Sep 2005
2,372 Posts
Quote:
Originally Posted by wmcneal
A friend of mine built one of these planes with two BP21s and 3s li-pos. I saw it fly for the first time today. It was awesome! It had plenty of power to take off from the grass field where we fly.
Did he add wheels then, or did it just skid along the ground?
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Old Jun 25, 2006, 11:15 AM
AMA 125691
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Jacksonville Florida
Joined Jul 2002
2,240 Posts
He just skidded along the ground
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