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Jan 09, 2009, 11:10 AM
Flying electric since 1986
Mark Wolf's Avatar
Quote:
Originally Posted by Jim Young
Photos????
There are photos.
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Jan 09, 2009, 12:56 PM
Registered User
Ken Myers's Avatar
I see the photos.
Maybe we kept Jim up too late last night at the meeting.
Jan 09, 2009, 04:12 PM
Flying electric since 1986
Mark Wolf's Avatar
Quote:
Originally Posted by Ken Myers
I see the photos.
Maybe we kept Jim up too late last night at the meeting.
My momma always told me that if you play with your wing release lever too much you could go blind...
Jan 09, 2009, 06:16 PM
Designer/Builder
Jim Young's Avatar
Must be my PC at work! I'll have to complain to my boss about the defective equipment! Now where did a put that hobby knife?

-Jim
Jan 11, 2009, 11:29 AM
Flying electric since 1986
Mark Wolf's Avatar
Two of the formers in the forward fuselage "float" above the crutch assembly, held in place by 3 3/16 stringers and eventually 1/16 sheeting. I laid the stringers in place over the existing formers and dry fit the two floating formers in their approximate locations. When satisfied I glued the stringers to the full formers. I the double checked that the two new formers were square and in the correct locations before locking them in place with CA.







Last edited by Mark Wolf; Aug 03, 2011 at 10:23 AM.
Jan 12, 2009, 05:26 AM
Designer/Builder
Jim Young's Avatar
Can you still get the battery tray out?
Jan 12, 2009, 06:32 AM
Flying electric since 1986
Mark Wolf's Avatar
Quote:
Originally Posted by Jim Young
Can you still get the battery tray out?
Busted! I managed to get one drop of CA on the tray and locked it up tight.

Luckily I was able to get it free with some solvent and a good tug. All is well now.
Jan 13, 2009, 02:57 PM
senior member
sammy's Avatar
I'm hoping this model Wright Cyclone (Williams Bros) that I built decades ago will fit the YMF 45in. model. Some special aerobat airshow models had nine cylinders. I may modify the plane to something like a UPF-7. This model engine is just under 5 in. dia. This cowl has a diameter of just under 6 inches. . What do you think, Jim Young?

Sammy
Last edited by sammy; Jan 13, 2009 at 03:38 PM.
Jan 13, 2009, 06:48 PM
Flying electric since 1986
Mark Wolf's Avatar
The cowling on this model has an outside diameter on 5 inches. Obviously anything is possible, but using your dummy engine would likely require redesigning the cowl, firewall, and battery tray and/or cutting up your dummy engine to suit.
Jan 13, 2009, 08:17 PM
senior member
sammy's Avatar
Thanks, Mark...Obviously, my cowl won't fit, but the engine is actually 4.5 in. in diameter, so it may fit a built-up cowl, perhaps a hair larger. On second thought, I may get a vac formed engine from Dare, and not cut up the Williams Cyclone.
Jan 13, 2009, 09:42 PM
Flying electric since 1986
Mark Wolf's Avatar
Quote:
Originally Posted by sammy
Thanks, Mark...Obviously, my cowl won't fit, but the engine is actually 4.5 in. in diameter, so it may fit a built-up cowl, perhaps a hair larger. On second thought, I may get a vac formed engine from Dare, and not cut up the Williams Cyclone.
Fitting inside the cowl isn't the issue. You would still need to redesign the firewall. Jim has designed this so that the firewall itself is the dummy engine. If you want to use another dummy you'll have to modify the design to move the firewall back and come up with a new cowl mount.

Nothing impossible, just wanted to let you know it wouldn't be a plug and play deal.
Jan 14, 2009, 05:47 AM
Designer/Builder
Jim Young's Avatar
Take a look at post #17, and you'll see what Mark is talking about. You can add a simple balsa crankcase, and some aluminum tube for a reasonable dummy motor. Check out my Wedell-Williams Model 44 build for what I did there.

I like to mount outrunners from the front. This seems to me to be the best way (can of worms officially opened) to do it. I just don't like the idea of all that weight spinning in front of the firewall (magnet can and prop). I know a lot of designs do that, but I think they are susceptible to bent shafts and bent cans which could really mess up your motor. While you can still get a bent shaft mounting from the front, the damage shold be limited to the shaft.

$0.02

-Jim
Jan 14, 2009, 08:32 AM
Registered User
E-Challenged's Avatar
You really have to impact something hard to bend a shaft on an outrunner, I haven't done it yet in a number of crashes and prefer using the rear mounts and conventional firewalls. It is possible to damage bearings due to hard impacts. I like to attach ring cowls to the firewall with velcro for quick removal and easy access. On my Stinson Reliant, I had to have the lipo pack protrude through the firewall to get cg right and need to remove prop and cowl to remove/change packs.
Jan 14, 2009, 09:07 AM
Flying electric since 1986
Mark Wolf's Avatar
Both types of mounts have their pros and cons. I'd prefer to have a the option of a more detailed dummy engine, but Jim's method is very funtional and can be detailed as well.

Personally, I don't find outrunner shafts any more difficult to bend than an inrunner with an equal sized shaft. One of my models currently has an outrunner with a bent shaft. That model has never been crashed. The shaft bent from catching the prop on landing (belly landing, no gear on the model).
Jan 14, 2009, 06:00 PM
Flying electric since 1986
Mark Wolf's Avatar
Horizontal stab and elevators ready for hinging. Once I finish the hinges, I'll cut the elevators free and then cut both the elevators and stab in half at the center. The halves will plug into tubes fixed in the vertical stabilizer.

Last edited by Mark Wolf; Aug 03, 2011 at 10:23 AM.


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