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Apr 16, 2018, 11:00 AM
Retired CAD guy
birdofplay's Avatar
I hope this clears up any questions and provides a good focal point for further discussion.

If we need a another/different pdf of other parts , just let me know.

Bob @ Hoosier Cutout Service
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Apr 16, 2018, 02:56 PM
Registered User

Witch


Otto:
Bob sent me the PDF files today, which I tiled, and all of the parts that I have matched perfectly!
In your directions for laying out the position of the motor mount, it states from the front (the collar) - does that mean I should measure from the absolute forward end of the foam or from where the collar would be. That may be my problem with the correct position of the motor mount.
In my previous post, I asked about the light ply doublers.
Regards,
Don
Apr 16, 2018, 05:55 PM
Quote:
Originally Posted by dong727
Otto:
Bob sent me the PDF files today, which I tiled, and all of the parts that I have matched perfectly!
In your directions for laying out the position of the motor mount, it states from the front (the collar) - does that mean I should measure from the absolute forward end of the foam or from where the collar would be. That may be my problem with the correct position of the motor mount.
In my previous post, I asked about the light ply doublers.
Regards,
Don
I think you hit on the issue. The measurement is from where the 5.5 inch line intersects the collar.

I used light 3 ply 1/8 inch plywood. It is fairly cheap.

Otto
Apr 16, 2018, 06:14 PM
Retired CAD guy
birdofplay's Avatar
Does this pic help ?

https://static.rcgroups.net/forums/a...200-78-17a.jpg

It's from Post # 11 on page 2 of this thread.
https://www.rcgroups.com/forums/show...6&postcount=17

Post #19 has another variation and pic as well.
https://static.rcgroups.net/forums/a...15-108-22b.jpg
Jul 05, 2018, 11:34 AM
Registered User

Hat Flutter


Otto:
Have you made any progress on the hat flutter problem?
Regards,
Don
Jul 05, 2018, 03:58 PM
Quote:
Originally Posted by dong727
Otto:
Have you made any progress on the hat flutter problem?
Regards,
Don
If built according to the log, there is not a flutter issue.
Jul 21, 2018, 12:36 PM
Registered User

Witch Arms


Otto:
I just installed the arms on my witch and they appear to be vulnerable if she falls on her side. Any way to solve this problem or perhaps reinforce the arms?
Regards,
Don
Jul 21, 2018, 01:52 PM
Retired CAD guy
birdofplay's Avatar
Don,

Got your post.
I just them as they were designed.
I can't find a downside for being the same tho.

Bob
Last edited by birdofplay; Jul 21, 2018 at 01:58 PM.
Jul 21, 2018, 02:01 PM
Retired CAD guy
birdofplay's Avatar
Once again , for 2018,

It's never too early to start your Halloween projects.
It's only ~ 3 months away !!!

Bob @ Hoosier Cutout Service
Jul 21, 2018, 03:42 PM
Quote:
Originally Posted by dong727
Otto:
I just installed the arms on my witch and they appear to be vulnerable if she falls on her side. Any way to solve this problem or perhaps reinforce the arms?
Regards,
Don
With the cape attached the arms can't hit the ground, the edge of the cape will. Arms have been quite durable.
Jul 22, 2018, 04:31 PM
Registered User

Witch Arms


Otto:
The witch kit that I received from Bob had only two forearms of different dimensions. The longer arms appeared more feminine to me, so that's why I chose to duplicate the longer arm. Obviously, that was a mistake as the arms contact the surface before the cape. Should I assume that the shorter arms are the correct ones? If you look at the pictures, you will see that the elbows stick out further than the edge of the cape when it's on it's side. I plan to replace the arms to solve the problem. Any advice?
I asked Bob why he sent me two arms with different dimensions and he said that is what you sent him. You can see it in his most recent post.
Regarding flutter....on your post 30 you said that the witch's hat had a flutter problem at high speed and that you were going to try experimenting with different air foil shapes to solve the problem. That's why I asked the question. There was no further mention of it.
This project is a little more challenging than I thought it would be...and you warned me...you obviously put a lot of thought and time into producing it.
Best regards,
Don
Jul 22, 2018, 04:44 PM
Retired CAD guy
birdofplay's Avatar
Otto, I believe, was attempting to make it look Life Like, versus purely symmetrical.

The Kit comes WITH a short and long arm as shown in post 188 .

It looks like you are doing a a meticulous ans terrific build.

The Hat could be augmented with another layer of itself, for stiffness. Minimal weight gain !
Or some smaller version of the Hat for even less weigh gain.

I usually put "some" extra foam in with kits as I pack them .
If you don't have enough ? ...
I could send some more, larger pieces to experiment with.

Bob
Jul 22, 2018, 11:53 PM
The witch kit that I received from Bob had only two forearms of different dimensions. The longer arms appeared more feminine to me, so that's why I chose to duplicate the longer arm. Obviously, that was a mistake as the arms contact the surface before the cape. Should I assume that the shorter arms are the correct ones? If you look at the pictures, you will see that the elbows stick out further than the edge of the cape when it's on it's side. I plan to replace the arms to solve the problem. Any advice?

The arms were modeled on the female form so they are feminine. I like the look of the original arms in the air. I haven't had mine together since Halloween so my elbows may touch but trust me when I say they never contact the ground when she falls over on landing. Do whatever you want with the arms. She will still fly well.

I asked Bob why he sent me two arms with different dimensions and he said that is what you sent him. You can see it in his most recent post.

Regarding flutter....on your post 30 you said that the witch's hat had a flutter problem at high speed and that you were going to try experimenting with different air foil shapes to solve the problem. That's why I asked the question. There was no further mention of it.

The original design didn't have the top of the hat (peak) pivot. This is the part that fluttered and produced a sense of instability around neutral. Since pivoting the peak, the hat has had no issues.

This project is a little more challenging than I thought it would be...and you warned me...you obviously put a lot of thought and time into producing it.

Landings are the only real challenge with her. About 30% of the time there are minor repairs to be done. Most can be performed at the field with duct tape and permanently repaired back at the hangar.
Jul 29, 2018, 03:04 PM
Registered User

Control Throws & CG


Otto:
The control throws that you recommend of 3" and 5" : Is that the total movement or each direction?
How much lead did you add to get your CG correct? Mine is calling for about 9 oz.
Regards, Don
Jul 30, 2018, 12:51 AM
Quote:
Originally Posted by dong727
Otto:
The control throws that you recommend of 3" and 5" : Is that the total movement or each direction?
How much lead did you add to get your CG correct? Mine is calling for about 9 oz.
Regards, Don
Each direction and the elevator center is 1" up. I added about 4 oz on one of the three I've built. 9oz sounds like a lot. Maybe a long broom or a lot of paint to blame.


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